Point-of-care diagnostics

Lab on Chip technologies have enabled the possibility of novel μTAS devices (micro Total Analysis System) that could drastically improve health care services for billions of people around the world. However, serious drawbacks that reside in fluid handling technology currently available for these systems often restrict the commercialization of such devices. This work demonstrates a novel fluid handling method as a possible alternative to current micropumping techniques for disposable microfluidic chips. This technology is based on a single use, low cost, thermal micropumping system in which expandable microsphere mixtures are activated by commercial grade laser diodes to achieve flow rates as high as 2.2 μl/s and total volumes over 160 μl. With the addition of a volume dependent shut off valve, nanoliter repeatability is realized. Pressure and heat transfer related data are presented. Finally, the possible prospects and limitations of this technology as a core element in unified optofluidic systems are discussed.

Iron deficiency (ID) is an urgent public health problem that has devastating effects on maternal and child health. However, due to poor access and affordability, screening and diagnosis for ID is often limited to proxy hemoglobin measurements alone. Here, we report the development and validation of ironPhone, a mobile-device coupled portable diagnostics for quantification of serum ferritin concentrations, an iron status biomarker, within a few minutes, from a drop of fingerprick blood. The ironPhone diagnostic platform comprises of a smartphone accessory, an app, and a disposable lateral flow immunoassay test strip to quantify serum ferritin. For initial validation in the lab, we optimized and evaluated the performance of ironPhone with known ferritin concentrations in spiked buffer and serum samples. Following lab validation, we performed a human validation by collecting fingerprick whole blood samples from 20 participants to assess iron status using ironPhone and compared the results with the laboratory standard IMMULITE 2000 analyzer. Findings from the ironPhone for the buffer and spiked serum samples provided a calibration curve with R 2 values of 0.97 (n=27) and 0.93 (n=12), respectively. On comparison with the laboratory standard IMMULITE analyzer in whole blood samples, a correlation of 0.92 (P < 0.0001) was observed with a sensitivity of over 90% for predicting ID (ferritin < 15.0 µg/L) via the ironPhone, demonstrating its promise for iron status assessment at the point-of-care.

Objective: This study was done to assess the accuracy of Accutrend GCT meter in determining blood cholesterol levels in our setup, with an aim to recommend its use in clinical practice
Methods: This cross sectional study was conducted on 251 healthy volunteers from April to May 2013. Capillary whole blood samples were obtained using sterile lancets and cholesterol levels were measured using Accutrend GCT meter (Roche Diagnostics, Mannheim, Germany) using the standard technique. Three ml whole blood was also collected in plain tubes by the same operator without applying a tourniquet. Serum cholesterol levels were determined using Merck Microlab 300 Automated Clinical Chemistry Analyser the same day. The laboratory technician performing this test was blinded to results obtained with Accutrend GCT meter. The seven patients with readings beyond the analytic range of the Accutrend GCT meter were excluded, meaning that data analysis was performed on 244 results only.
Results: Results of 182 males and 62 females having a mean age of 38.54± 15.25 years were analysed. There was a significant difference in mean cholesterol levels measured by Accutrend GCT and Microlab-300 (4.73± 0.74mmol/l and 4.67± 0.86 mmol/l; p=0.021), producing a measurement bias of 1.43% with Accutrend GCT meter. A strong positive correlation was found between the results of the two techniques (r=0.852 ,p<0.001).
Conclusions: Accutrend GCT meter provides accurate measurement of blood cholesterol levels and its use should be encouraged for point-of-care measurements.

A Point of Care (POC) test for measurement of antibody or cortisol concentrations has given rapid feedback to coaches and support staff in Premier League soccer clubs within a matter of minutes from sample collection.  This has been useful in assessing fatigue levels, immune status and readiness to train / compete and offers a considerable time advantage over standard laboratory methods.  This current paper assesses a new POC reader, which is smaller, quicker and cheaper than the current model.
A total of 48 saliva samples taken during routine monitoring a cohort of English Premier League soccer players (23.5 ± 6.4 yrs) using IPRO OFC kits on two separate occasions for the measurement of cortisol on the standard IPRO ESE-Quant LFD reader and the new IPRO Cube reader.  The next week 50 samples from the same cohort were measured for sIgA concentration with the IPRO Cube reader and the same samples analysed the next day via ELISA.
The cortisol LFD showed good agreement on both readers; r = 0.96 (95% CI 0.93 – 0.98) with typical error of estimate 1.18 nM (95% CI 0.98 – 1.48) and no difference between the mean values on each reader: ESE-Quant 7.5 nM (range 2.73 – 23.5 nM) v Cube 7.1 nM (range 2.24 – 25.8).
The sIgA LFD measured with the Cube reader showed good agreement with ELISA r = 0.97 (95% CI 0.95 – 0.98) with typical error of estimate 33.24 μg/mL and no difference between the mean values on the Cube and ELISA: Cube mean 215.6 ± 163.8 μg/mL (range 34.7 – 621.1 μg/mL) v ELISA mean 205.4 ± 142.1 (range 34.91 600 μg/mL.
The new Cube POC device shows suitable validity for use in the sporting environment and represents savings in cost and analysis time in comparison to previous methods.

Herein we report the facile synthesis of a quaternary nanocomposite material (hemin–silver coated gold– graphene oxide) and evaluate its efficacy as a novel peroxidase mimetic. A strong synergistic coupling between the various components involved results in an excellent catalytic performance of this nanocomposite. A comparison of the different morphologies of the silver coated gold particles strongly indicates a greater sensitivity of the nanostar morphology over the nanoparticle morphology owing to its high surface-to-volume ratio. Furthermore, the immobilization of hemin and silver coated gold nanostars on a graphene oxide sheet framework imposes a nanoscale confinement, effectively augmenting the overall catalytic performance of the composite. The nanocomposite followed typical Michaelis–Menten theory and electrochemical analysis suggested facilitation of accelerated electron transfer between TMB and H 2 O 2. A K M value of 2.75 mM À1 suggested a high affinity of the nanocomposite towards TMB. Furthermore, a 2.8 times increase in the maximum reaction rate compared to HRP established the high catalytic activity of the nanocomposite. The nanocomposite demonstrates a nanomolar range sensitivity towards hydrogen peroxide and glucose (limit of detection ¼ 1.26 nM and 425 nM). The nanocomposites have also been employed to develop a paper-based point-of-care diagnostic device. The device has been utilized for detection of glucose in human blood serum samples with satisfactory results.

While developing an effective vaccine can take months up to years, detection of infected patients seems like one of the best ideas for controlling the situation. The role of biosensors in containing highly pathogenic viruses, saving lives and economy is evident. A new competitive numerical platform specifically for designing microfluidic-integrated biosensors is developed and presented in this work. Properties of the biosensor, sample, buffer fluid and even the microfluidic channel can be modified in this model. This feature provides the scientific community with the ability to design a specific biosensor for requested point-of-care (POC) applications. First, the validation of the presented numerical platform against experimental data and then results and discussion, highlighting the important role of the design parameters on the performance of the biosensor is presented. For the latter, the baseline case has been set on the previous studies on the biosensors suitable for SARS-CoV, which has the highest similarity to the 2019 nCoV. Subsequently, the effects of concentration of the targeted molecules in the sample, installation position and properties of the biosensor on its performance were investigated in 11 case studies. The presented numerical framework provides an insight into understanding of the virus reaction in the design process of the biosensor and enhances our preparation for any future outbreaks. Furthermore, the integration of biosensors with different devices for accelerating the process of defeating the pandemic is proposed.

The development of good quality and affordable ultrasound machines has led to the establishment and implementation of numerous point-of-care ultrasound (POCUS) protocols in various medical disciplines. POCUS for major infectious diseases endemic in tropical regions has received less attention, despite its likely even more pronounced benefit for populations with limited access to imaging infrastructure. Focused assessment with sonography for HIV-associated TB (FASH) and echinococcosis (FASE) are the only two POCUS protocols for tropical infectious diseases, which have been formally investigated and which have been implemented in routine patient care today. This review collates the available evidence for FASH and FASE, and discusses sonographic experiences reported for urinary and intestinal schistosomiasis, lymphatic filariasis, viral hemorrhagic fevers, amebic liver abscess, and visceral leishmaniasis. Potential POCUS protocols are suggested and technical as well as training aspects in the context of resource-limited settings are reviewed. Using the focused approach for tropical infectious diseases will make ultrasound diagnosis available to patients who would otherwise have very limited or no access to medical imaging.

Low-and middle-income countries (LMICs) continue to face major challenges in providing high-quality and universally accessible health care. Researchers, policy makers, donors, and program implementers consistently strive to develop and provide innovative approaches to eliminate geographical and financial barriers to health care access. Recently, interest has increased in using mobile health (mHealth) as a potential solution to overcome barriers to improving health care in LMICs. Moreover, with use increasing and cost decreasing for mobile phones and Internet, mHealth solutions are becoming considerably more promising and efficient. As part of mHealth solutions, biomedical signals collection and processing may play a major role in improving global health care. Information extracted from biomedical signals might increase diagnostic precision while augmenting the robustness of health care workers' clinical decision making. This paper presents a high-level framework using biomedical signal processing (BSP) for tackling diagnosis of noncommunicable diseases, especially in LMICs. Researchers can consider each of these elements during the research and design of BSP-based devices, enabling them to elevate their work to a level that extends beyond the scope of a particular application and use. This paper includes technical examples to emphasize the applicability of the proposed framework, which is relevant to a wide variety of stakeholders, including researchers, policy makers, clinicians, computer scientists, and engineers.

INTRODUCTION: The use of tests to measure salivary biomarker responses has gathered momentum in sports, exercise and behavioural sciences.  A Point of Care (POC) platform using lateral flow (LFD) technology, which takes jus over 10 minutes to measure salivary IgA has previously been validated (Coad et al., 2015).  The ability to multiplex sampling would save processing time and speed up the delivery of data in the applied setting when assessment of more than one marker is desired.  Salivary alpha amylase (sAA) is another antimicrobial protein that can be measured in conjunction with IgA, using a novel antibody capture, rather than enzymatic, method.  The present study examines the performance of a dual IgA / sAA POC test within the sporting environment.
METHODS: A total of 56 saliva samples were taken from 3 cohorts of professional soccer players, from 3 English clubs, using Ipro oral fluid collector (OFC) kits (Ipro Interactive Ltd, Wallingford, UK), during standard monitoring procedures. The samples were assessed immediately for sIgA and sAA concentrations in the field using the POC LFD kits and reader.  The samples were then taken to a laboratory for subsequent analysis by ELISA. The measurement range on ELISA was 18.5 – 600 µg/ml for IgA and 20 – 4000 µg/ml for sAA; on the POC platform it was 18.5 -900 µg/ml for IgA and 20 – 4000 µg/ml for sAA. Six samples were run as six replicates to assess within assay reliability on the POC test.
RESULTS: The sIgA values ranged from 33 – 550 µg/ml on ELISA and 28 – 684 µg/ml on the POC test; whilst sAA values ranged from 68 – 1698 µg/ml on ELISA and 52 - 4000 µg/ml on the POC test. The Pearson correlation between test types was r = 0.87 (95% CI, 0.78 – 0.92) for sAA and r = 0.90 (95% CI, 0.84 – 0.94), showing good validity of the POC method for both assays. Reliability was better for IgA with the mean within CV for 6 replicates at 7.46% (range 3.42 – 14.42%) than sAA where the mean CV was 12.86% (range 9.91 – 15.54%).
CONCLUSION: The dual analyte IgA & sAA POC test showed good agreement with ELISA and good reliability.  Given the considerable time advantage over traditional methods, this new test is of benefit to applied practitioners in sports and exercises science who need rapid data.

References
Coad, S., et al. (2015). Res. in Sports Med. DOI 10.1080/15438627.2015.1005300

Clostridium difficile is worldwide most common cause of health care associated diarrhea in children and infants and is considered significant morbidity and mortality. Little is known about it epidemiology in resource limited settings. The current study was conducted at The Children’s Hospital and The Institute of Child Health, Lahore from July 2017 to December 2017 to determine the frequency of Clostridium difficile infection in paediatric patients. A total number of 61 samples were selected for this study and subsequently collected from four different wards of the hospital and processed for routine microbiological analysis. The presence of toxin was identified by specific kit using Xpect kit for C.difficile toxin. From the total of 61 samples selected, 34 (55.7%) samples belong to male patients and 27 (44.3%) samples belong to female patients. Frequency of the reactive samples came up to be 3 (4.9%) and that of the non-reactive were 58 (95.1%). Although samples were taken from four different wards but most importantly 31 (50.8%) samples were taken from Gastroenterology ward, out of which 3 (4.9%) were reactive for C. difficile toxin and remaining 28 (45.9%) were non reactive. Our results demonstrated a significant occurrence of C. difficile infection in this hospital population. There is a need to further evaluate the role of C. difficile in causing antibiotic associated diarrhea.

In this work, a non-invasive Electrochemical
Impedance Spectroscopy (EIS) Point-of-Care (PoC) diagnostic
device to detect the creatinine concentration from the serum is
presented. A Micro-Electro-Mechanical Systems (MEMS)
sensor was used for measuring the electrochemical properties
of Sample Under Test (SUT). The EIS technique was utilised
along with the sensor to find out different creatinine
concentrations in heat-inactivated serum samples. Creatinine
specific Molecularly Imprinted Polymerization (MIP)-coated
sensor was used to measure the levels of creatinine followed by
the development of a LoRaWAN-based PoC diagnostic device.
In the next step, the results obtained from the diagnostic device
were cross-verified by using standard Creatinine Colorimetric
Assay Kit. The results were found to be promising to further
continue the research.

Despite the copious amount of research on the design and operation of micromixers, there are few works regarding manufacture technology aimed at implementation beyond academic environments. This work evaluates the viability of xurography as a rapid fabrication tool for the development of ultra-low cost microfluidic technology for extreme Point-of-Care (POC) micromixing devices. By eschewing photolithographic processes and the bulkiness of pumping and enclosure systems for rapid fabrication and passively driven operation, xurography is introduced as a manufacturing alternative for asymmetric split and recombine (ASAR) micromixers. A T-micromixer design was used as a reference to assess the effects of different cutting conditions and materials on the geometric features of the resulting microdevices. Inspection by stereographic and confocal microscopy showed that it is possible to manufacture devices with less than 8% absolute dimensional error. Implementation of the manufacturing methodology in modified circular shape-based SAR microdevices (balanced and unbalanced configurations) showed that, despite the precision limitations of the xurographic process, it is possible to implement this methodology to produce functional micromixing devices. Mixing efficiency was evaluated numerically and experimentally at the outlet of the microdevices with performances up to 40%. Overall, the assessment encourages further research of xurography for the development of POC micromixers.

Biosensors are promising tools for achieving point-of-care, real-time, human health, and performance monitoring. Nanotechnology can catalyze the process of biosensors miniaturization or can be used for inventing whole-new types of biosensors. The development of nanobiosensors, along with the maturation of artificial intelligence and Internet-of-Things applications, can inaugurate a new era for in-situ predictive diagnostics, telemedical practice, and general scientific understanding. This potential is of particular interest for medical fields responsible to ensure human health, safety, and performance in extreme environments, with utmost example: manned spaceflight and planets habitation. This review focuses on biosensing approaches in space, but extends further to biosensing applications in aviation, military, and sports, as other situations of extreme environmental conditions for the human body. Lastly, some miscellaneous types of nanobiosensors are mentioned, in order to provide an insight of the potential that future biosensing systems hold. Hopefully, this work will encourage nanobiosensor developers to work closely with the end-users, so that quality-by-design can be achieved, and thus the full potential of this next-generation technology can be harvested.

Background

Successful point-of-care testing, namely ensuring the completion of the test and treat cycle in the same encounter, has immense potential to reduce diagnostic and treatment delays, and impact patient outcomes. However, having rapid tests is not enough, as many barriers may prevent their successful implementation in point-of-care testing programs. Qualitative research on diagnostic practices may help identify such barriers across different points of care in health systems.

Methods

In this exploratory qualitative study, we conducted 78 semi-structured interviews and 13 focus group discussions in an urban and rural area of Karnataka, India, with healthcare providers (doctors, nurses, specialists, traditional healers, and informal providers), patients, community health workers, test manufacturers, laboratory technicians, program managers and policy-makers. Participants were purposively sampled to represent settings of hospitals, peripheral labs, clinics, communities and homes, in both the public and private sectors.

Results

In the Indian context, the onus is on the patient to ensure successful point-of-care testing across homes, clinics, labs and hospitals, amidst uncoordinated providers with divergent and often competing practices, in settings lacking material, money and human resources. We identified three overarching themes affecting point-of-care testing: the main theme is ‘relationships’ among providers and between providers and patients, influenced by the cross-cutting theme of ‘infrastructure’. Challenges with both result in ‘modified practices’ often favouring empirical (symptomatic) treatment over treatment guided by testing.

Conclusions

Even if tests can be conducted on the spot and infrastructure challenges have been resolved, relationships among providers and between patients and providers are crucial for successful point-of-care testing. Furthermore, these barriers do not act in isolation, but are interlinked and need to be examined as such. Also, a test alone has only limited power to overcome those difficulties. Test developers, policy-makers, healthcare providers and funders need to use these insights in overcoming barriers to point-of-care testing programs.

New tools are needed to enable rapid detection, identification, and reporting of infectious viral and microbial pathogens in a wide variety of point-of-care applications that impact human and animal health. We report the design, construction, and characterization of a platform for multiplexed analysis of disease-specific DNA sequences that utilizes a smartphone camera as the sensor in conjunction with a hand-held " cradle " that interfaces the phone with a silicon-based microfluidic chip embedded within a credit-card-sized cartridge. Utilizing specific nucleic acid sequences for four equine respiratory pathogens as representative examples, we demonstrated the ability of the system to utilize a single 15 μL droplet of test sample to perform selective positive/negative determination of target sequences, including integrated experimental controls, in approximately 30 min. Our approach utilizes loop-mediated isothermal amplification (LAMP) reagents predeposited into distinct lanes of the microfluidic chip, which when exposed to target nucleic acid sequences from the test sample, generates fluorescent products that when excited by appropriately selected light emitting diodes (LEDs), are visualized and automatically analyzed by a software application running on the smartphone microprocessor. The system achieves detection limits comparable to those obtained by laboratory-based methods and instruments. Assay information is combined with the information from the cartridge and the patient to populate a cloud-based database for epidemiological reporting of test results.

A novel paper-based device for colorimetric detection of uric acid was developed based on the peroxidase-like activity of gold nanoparticles–graphene conjugates (AuNPs–GO). Theoretical models were utilized for designing a device that was further verified by simulation and experimentation. Detection of uric acid was then carried out by initially soaking the paper in an AuNPs–GO solution and subsequently pipetting TMB– H 2 O 2 solution on it. Detection was achieved by measuring the color change when uric acid interacted with AuNPs–GO. A significant reduction in the blue coloration of the paper to white color was observed in a brief time of 5 minutes. Moreover, a very low detection limit of 4 ppm for uric acid was obtained on paper by visualization with the naked eye. The assembly of AuNPs within the GO matrix resulted in many active sites, which were the reason for the low detection limit. The practicality of the device was also examined by testing it on several blood serum samples. The results were in agreement with clinical results and also showed a high selectivity towards uric acid. The device provides a real-time, rapid and easy-to-use platform for the detection of uric acid for clinical purposes.

Background
The core objective of any point-of-care (POC) testing program is to ensure that testing will result in an actionable management decision (e.g. referral, confirmatory test, treatment), within the same clinical encounter (e.g. POC continuum). This can but does not have to involve rapid tests. Most studies on POC testing focus on one specific test and disease in a particular healthcare setting. This paper describes the actors, technologies and practices involved in diagnosing major diseases in five Indian settings – the home, community, clinics, peripheral laboratories and hospitals. The aim was to understand how tests are used and fit into the health system and with what implications for the POC continuum.

Methods
The paper reports on a qualitative study including 78 semi-structured interviews and 13 focus group discussions with doctors, nurses, patients, lab technicians, program officers and informal providers, conducted between January and June 2013 in rural and urban Karnataka, South India. Actors, diseases, tests and diagnostic processes were mapped for each of the five settings and analyzed with regard to whether and how POC continuums are being ensured.

Results
Successful POC testing hardly occurs in any of the five settings. In hospitals and public clinics, most of the rapid tests are used in laboratories where either the single patient encounter advantage is not realized or the rapidity is compromised. Lab-based testing in a context of manpower and equipment shortages leads to delays. In smaller peripheral laboratories and private clinics with shorter turn-around-times, rapid tests are unavailable or too costly. Here providers find alternative measures to ensure the POC continuum. In the home setting, patients who can afford a test are not/do not feel empowered to use those devices.

Conclusion
These results show that there is much diagnostic delay that deters the POC continuum. Existing rapid tests are currently not translated into treatment decisions rapidly or are not available where they could ensure shorter turn-around times, thus undermining their full potential. To ensure the success of POC testing programs, test developers, decision-makers and funders need to account for such ground realities and overcome barriers to POC testing programs.

Without a doubt, the current global pandemic affects all walks of our life. It affected almost every age group all over the world with a disease named COVID-19, declared as a global pandemic by WHO in early 2020. Due to the high transmission and moderate mortality rate of this virus, it is also regarded as the panic-zone virus. This potentially deadly virus has pointed up the significance of COVID-19 research. Due to the rapid transmission of COVID-19, early detection is very crucial. Presently, there are different conventional techniques are available for coronavirus detection like CT-scan, PCR, Sequencing, CRISPR, ELISA, LFA, LAMP. The urgent need for rapid, accurate, and cost-effective detection and the requirement to cut off shortcomings of traditional detection methods, make scientists realize to advance new technologies. Biosensors are one of the reliable platforms for accurate, early diagnosis. In this article, we have pointed recent diagnosis approaches for COVID-19. The review includes basic virology of SARS-CoV-2 mainly clinical and pathological features. We have also briefly discussed different types of biosensors, their working principles, and current advancement for COVID-19 detection and prevention.

Halitosis (bad breath) can be a cause of anxiety, depression and psychosocial stress, with pathological changes in the oral
microbiota playing an important role in its development. Despite its prevalence, studies on the microbiology of halitosis are rare in Nigeria. This study determines the presence of five putative periodontal pathogens viz: Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola on the tongue dorsa of halitosis and non-halitosis patients using a 16S rDNA-directed polymerase chain reaction assay. Furthermore, an association of these bacteria with oral malodour [as assessed by volatile sulphur compounds (VSC) measurements] with
a portable sulphide monitor, the Halimeter (Interscan Corp, Chatsworth, California), was performed. The results showed that the prevalence of halitosis in this environment as defned by VSC level above 160 ppb is 14.9%. Halitosis is afected by gender with males having it more than the females. Males also tend to present more with self-reported complaints of halitosis than females. Age does not appear to contribute to the incidence of halitosis. Fusobacterium nucleatum, P. gingivalis,
P. intermedia are responsible for increased production of VSCs in halitosis patients while A. actinomycetemcomitans and T. denticola appear to play no part in the production of VSCs. Evaluation of halitogenic bacteria and VSCs may potentially become a surrogate biomarker for monitoring halitosis. Targeted assessment of putative halitogenic bacteria may provide a rapid point-of-care diagnostic tool for halitosis.

The aim of this study was to study the diagnostic parameters in
brain tuberculosis (meningeal and parenchymal)
Material and Methods: This study was conducted in the
department of Neurosurgery and Neurology SKIMS for a period
of two years. A total of 61 patients presenting with brain
tuberculosis admitted at skims during these two years were
included in the study.
Results: The most presenting symptom in our study was headache
found in 95.10% followed by vomiting found in 86.90% of
subjects, fever in 78.70%, altered sensorium in 49.20%, seizures in
19.70% and diplopia in18%. Out of 61 patients cranial nerve
involment was found in 34(55.73%) with 11 having more than two
cranial nerves involved. The most common cranial nerve involved
were 3rd and 6th. ADA was positive in 36 of 53 patients of TBM
with a sensitivity of 67.9% and a specificity of 75%. PCR proved
to be highly specific CT scan of head was abnormal in 56 out of
61 patients (91.8%). 12 (19.70%) were in stage I (meningeal
involvement only), 29 (47.50%) were in stage II (parenchymal
involvement only) and 15 (24.60%) were in stage III (both
parenchymal and meningeal invlolvement). The most common
finding in CT head was meningeal enhancement in 43 patients,
hydrocephalus in 37 patients and tuberculomas in 14 patients. The
most common sites of tuberculomas were frontal lobe (n=6;
42.8%), parietal lobe (n=4; 28.5%), followed by cerebellum in 2
patients and occipital in two. Nine patients had single and five
multiple tuberculomas. Of the 14 patients with tuberculomas,
hydrocephalus on CT was seen in 6 patients.
Conclusion: CT scan is a useful diagnostic tool even in very early
stages of TBM. Abnormalities reported on CT scan done are
hydrocephalus, infarcts, basal enhancement, and tuberculomas.
Normal study is reported in up to 20% of the cases.

We developed an affordable, highly sensitive, and specific paper-based microfluidic platform for fast multiplexed detections of important biomarkers in various body fluids, including urine, saliva, serum, and whole blood. The sensor array consisted of five individual sensing channels with various functionalities that only required a micro liter-sized sample, which was equally split into aliquots by the built-in paper microfluidics. We achieved the individual functionalizations of various bioreceptors by employing the use of wax barriers and 'paper bridges' in an easy and low-cost manner. Pyrene carboxylic acid-modified single-walled carbon nanotubes (PCA/SWNTs) were deposited by quantitative inkjet printing with an optimal 3-dimensional semiconductor density on a paper substrate. Multiple antibodies were immobilized onto the SWNTs surface for highly sensitive and specific field-effect transistor (FET)/chemiresistor (CR) biosensors. We explored the optimal sensing conditions for the paper-based CR biosensor to achieve high sensitivities and specificities towards the target biomarker proteins (human serum albumin (HSA) and human immunoglobulin G (HIgG)) and achieved an ultralow detectable concentration of HSA and HIgG at 1.5 pM. Besides, origami folding was employed to simplify the fabrication process further. The sensing platform described in this work was cost-effective, semi-automated, and user-friendly. It demonstrated the capability of having multiple sensing functions in one paper-based microfluidic sensing platform. It envisioned the potential of a point-of-care device with full-analysis for practical diagnostics in an ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to end-users) fashion for a quick test of targets of interest.

Humans are subjected to various diseases; hence, proper diagnosis helps avoid further disease consequences. One such severe issue that could cause significant damage to the human liver is the hepatitis C virus (HCV). Several techniques are available to detect HCV under various categories, such as detection through antibodies, antigens, and RNA. Although immunoassays play a significant role in discovering hepatitis viruses, there is a need for point-of-care tests (POCT). Some developing strategies are required to ensure the appropriate selection of POCT for HCV detection, initiate appropriate antiviral therapy, and define associated risks, which will be critical in achieving optimal outcomes. Though molecular assays are precise, reproducible, sensitive, and specific, alternative strategies are required to enhance HCV diagnosis among the infected population. Herein, we described and assessed the potential of various microfluidic detection techniques and confirmatory approaches used in present communities. In addition, current key market players in HCV chip-based diagnosis and the future perspectives on the basis of which the diagnosis can be made easier are presented in the present review.

Diagnostics (ISSN 2075-4418) is an international scholarly open access journal on medical diagnostics. It publishes original research articles, reviews, short communications, case reports and interesting images. There is no restriction on the length of the papers. Our aim is to encourage scientists to publish their experimental and theoretical
research in as much detail as possible. Full experimental and/or methodological details must be provided for research articles.

In this work, a simple, sensitive and selective label free colorimetric assay using palladium-gold nanorod as
nanozyme is reported for malathion detection. Study investigates the peroxidase potential of the nanozyme on
colorimetric substrates and explores the e ffect of selected organophosphates on their enzyme mimetic activity.
Palladium-gold nanozyme shows excellent peroxidase mimetic activity with O-phenylenediamine in the
presence of hydrogen peroxide. Its Kinetic parameters Km and kcat are better than horseradish peroxidase
which makes it a superior enzyme. Nanozyme is stable over a broad temperature range (4 –70 °C) and shows
high peroxidase activity from 2 to 6 pH. The peroxidase activity of nanozyme is selectively quenched with
increasing concentration of malathion and is the principle of developed assay. Assay has a lowest detection limit
of 60 ng/ml and shows no cross-reaction with other analogous organophosphates or metal salts. Validation on
tap water samples spiked with diff erent concentrations of malathion shows good recovery in the range of 80–
106%. Assay also displays good intra and inter-assay precision which lie in the range of 2.7– 6.1% and 3.2–5.9%
respectively. This study demonstrated the catalytic potential of palladium-gold nanorods, which can be
employed as nanozyme for developing highly sensitive detection methods

The goal of this project is to develop and utilize a microfluidic device to isolate and enrich tumor cells circulating in peripheral blood. Circulating tumor cells (CTCs) have been used as biomarkers for cancer diagnostics and prognosis. However, the rarity of these cells (roughly 1 in a billion) poses a technological challenge to sort and concentrate them. CTCs hold potential sources for early detection, characterization, monitoring of cancers, and development of personalized treatment. The project is currently funded by the US National Cancer Institute (NCI) of the National Institutes of Health (NIH).

Infectious diseases remain the world's top contributors to death and disability, and, with recent outbreaks of Zika virus infections there has been an urgency for simple, sensitive and easily translatable point-of-care tests. Here we demonstrate a novel point-of-care platform to diagnose infectious diseases from whole blood samples. A microfluidic platform performs minimal sample processing in a user-friendly diagnostics card followed by real-time reverse-transcription loop-mediated isothermal amplification (RT-LAMP) on the same card with pre-dried primers specific to viral targets. Our point-of-care platform uses a commercial smartphone to acquire real-time images of the amplification reaction and displays a visual read-out of the assay. We apply this system to detect closely related Zika, Dengue (types 1 and 3) and Chikungunya virus infections from whole blood on the same pre-printed chip with high specificity and clinically relevant sensitivity. Limit of detection of 1.56e5 PFU/mL of Zika virus from whole blood was achieved through our platform. With the ability to quantitate the target nucleic acid, this platform can also perform point-of-care patient surveillance for pathogen load or select biomarkers in whole blood.

Nano-textured super hydrophobic (SH) surfaces can achieve very high droplet contact angles (typically >150 •) and are furthermore associated with reduced surface adsorption of enzymes and other macro-molecules. The advantages of such SH surfaces have already been explored for electrostatic based digital microfluidic (DMF) devices where the high CA and the reduced surface adsorption largely benefits the handling and manipulation of complex biochemical samples/reagents. Liquid dielectrophoresis (LDEP) based digital microfluidic (DMF) technology has demonstrated its capability for achieving combinato-rial assays on standard hydrophobic surfaces. However, such devices suffer from similar issues as DMF devices when it comes to handling bio-reagents/samples where off-chip sample handling steps (wash-ing/buffer exchange) are often required prior to the on-chip bio-assay. In this work, we have optimized a comprehensive fabrication protocol to develop a nano-textured SH surface topology for LDEP device applications. The static and transient behavior of LDEP actuation over the SH surface has been investigated using an improved lumped model and furthermore experimentally verified using specifically tailored liquid samples. The developed SH surface has also been analyzed for liquid actuation of TAQ DNA polymerase enzyme which is a key component of most nucleic acid amplification assays. The performance of LDEP actuation of tailored liquid samples is analyzed and compared for both hydrophobic and SH surfaces. The reported work demonstrates that specific textured SH surfaces can successfully achieve reliable LDEP actuation and furthermore dispense/manipulate TAQ DNA polymerase enzyme and various other aqueous samples.

Early-stage diagnosis of a disease is important for better revival. Kidney function can be qualitatively as well as quantitatively checked by monitoring levels of creatinine in urine or serum samples. Thus, fast, portable, cost and time-effective Point-of-Care (PoC) devices are in high demand. In the current paper, an Internet of Thing (IoT) - associated creatinine specific, precise, fast and cost and time-effective PoC diagnostic device for the monitoring of creatinine levels from serum. An interdigital sensor coated with creatinine selective Molecularly Imprinted Polymer (MIP) by using Electrochemical Impedance Spectroscopy (EIS) for determining capacitance and resistive properties of the sample under test. A low power microcontroller-associated diagnostic device was manufactured for the quantitative measuring of creatinine levels from serum which transfers data to an IoT-associated cloud server. The collected data can be stockpiled and it is accessible to concern oncologist/ nephrologist located over distance for a long-distance patient healthcare facility. The developed sensing system covers a wide range of 5 - 12 ppm (normal) up to 50 ppm (highest upper limit of detection) which is over thrice the acceptable creatinine range in serum levels. It is suitable for prognostic and prophylactic PoC care facility for kidney patients. The presented biosensor system is fast, easy, handy but sensitive detection testing by using the presented PoC diagnostic device and the verification of the device is performed using standard Creatinine Colorimetric Assay Kit.

Microfluidics allows for the miniaturization of laboratory processes onto a compact disc (CD). A microfluidic CD provides a cost-effective, portable and automated diagnostic platform without the use of bulky equipment and complex machinery. This reduction in the cost, footprint, and user input allows for the development of tools suitable for point-of-care applications. One of the criteria for point-of-care applications is the ability to have long storage life. During storage, the reagents/chemicals in typical microfluidic CDs might evaporate and mix together before actual usage, compromising on the integrity of the result. To complement the use of capillary valves, this paper presents various available valves for vapor control, and introduces a hybrid capillary-flap valve for use in microfluidic CDs for point-of-care applications. © 2011 Springer-Verlag.

http://link.springer.com/chapter/10.1007/978-3-642-21729-6_144

Fungal diseases of plants are of great economic importance causing 70-80% of crop losses associated with microbial plant pathogens. Advanced on-site disease diagnostics is very important to maximize crop productivity. In this study, diagnostic systems have been developed for simultaneous detection and identification of six fungal pathogens using 48-well microarrays (micromatrices) for qPCR. All oligonucleotide sets were tested for their specificity using 59 strains of target and non-target species. Detection limit of the developed test systems varied from 0.6 to 43.5 pg of DNA depending on target species with reproducibility within 0.3−0.7% (standard deviation). Diagnostic efficiency of test systems with stabilized and freeze-dried PCR master-mixes did not significantly differ from that of freshly prepared microarrays, though detection limit increased. Validation of test systems on 30 field samples of potato plants showed perfect correspondence with the results of morphological identification of pathogens. Due to the simplicity of the analysis and the automated data interpretation, the developed microarrays have good potential for on-site use by technician-level personnel, as well as for high-throughput monitoring of fungal potato pathogens.

Background: Depending on a country's diagnostic infrastructure, patients and providers play different roles in ensuring that correct and timely diagnosis is made. However, little is known about the work done by patients in accessing diagnostic services and completing the 'test and treat' loop. Objective: To address this knowledge gap, we traced the diagnostic journeys of patients with tuberculosis, diabetes, hypertension and typhoid, and examined the work they had to do to arrive at a diagnosis. Methods: This paper draws on a qualitative study, which included 78 semi-structured interviews and 13 focus group discussions with patients, public and private healthcare providers, community health workers, test manufacturers, laboratory technicians, program managers and policy-makers. Data were collected between January and June 2013 in rural and urban Karnataka, South India, as part of a larger project on barriers to point-of-care testing. We reconstructed patient diagnostic processes retrospectively and analyzed emerging themes and patterns. Results: The journey to access diagnostic services requires a high level of involvement and immense work from patients and/or their caretakers. This process entails overcoming cost and distance, negotiating social relations, continuously making sense of their illness and diagnosis, producing and transporting samples, dealing with the social consequences of diagnosis, and returning results to the treating provider. The quality and content of interactions with providers were crucial for completion of test and treat loops. If the tasks became overwhelming, patients opted out, delayed being tested, switched providers and/or reverted to self-testing or self-treatment practices. Conclusion: Our study demonstrated how difficult it can be for patients to complete diagnostic journeys and how the health system works as far as diagnostics are concerned. If new point-of-care tests are to be implemented successfully, policymakers, program officers and test developers need to find ways to ease patient navigation through diagnostic services.

We present a new concept for rapid and fully portable Prostate Specific Antigen (PSA) measurement, termed “Lab-in-a-Briefcase”, which integrates an affordable microfluidic ELISA platform utilising a melt-extruded fluoropolymer Micro Capillary Film (MCF) containing 10 bore, 200 m internal diameter capillaries, a disposable multi-syringe aspirator (MSA) plus a sample tray pre-loaded with all required immunoassay reagents, and a portable film scanner for colorimetric signal digital quantitation. Each MSA can perform 10 replicate microfluidic immunoassays on 8 samples, allowing 80 measurements to be made in less than 15 minutes based on semi-automated operation and no requirement of additional fluid handling equipment. An assay was optimised for measurement of a clinically relevant range of PSA from 0.9 to 60.0 ng/ml in 15 minutes with CVs in the order of 5% based on intra-assay variability when read using a consumer flatbed film scanner. The PSA assay performance in the MSA remained robust in the presence of undiluted or 1:2 diluted and non-diluted human serum and or whole blood, where and the matrix effect could simply be overcome by extending the sample incubation times of the samples beyond 2 min. The PSA "Lab-in-a-briefcase" is particularly suited to a low-resource health setting where diagnostic labs and automated immunoassay systems are not accessible, by allowing PSA measurement outside the laboratory using affordable equipment.

This work describes a device for electrochemical ELISA designed for low-resource settings and diagnostics at the point of care. The device is fabricated entirely in hydrophobic paper, produced by silanization of paper with decyl trichlorosilane, and comprises two zones separated by a central crease: an embossed microwell, on the surface of which the antigen or antibody immobilization and recognition events occur, and a detection zone where the electrodes are printed. The two zones are brought in contact by folding the device along this central crease; the analytical signal is recorded from the folded configuration. Two proof-of-concept applications—an electrochemical direct ELISA for the detection of rabbit IgG as a model antigen in buffer, and an electrochemical sandwich ELISA for the detection of malarial histidine-rich protein from P. falciparum (Pf HRP2) in spiked human serum— show the versatility of this device. The limit of detection of the electrochemical sandwich ELISA for the quantification of Pf HRP2 in spiked human serum was 4 ng mL-1 (10^2 pmol L-1)—a value within the range of clinical relevant
concentrations.

This paper reports for the first time printed-circuit-board (PCB)-based label-free electrochemical detection of bacteria. The demonstrated immunosensor was implemented on a PCB sensing platform which was designed and fabricated in a standard PCB manufacturing facility. Bacteria were directly captured on the PCB sensing surface using a specific, pre-immobilized antibody. Electrochemical impedance spectra (EIS) were recorded and used to extract the charge transfer resistance (R ct) value for the different bacteria concentrations under investigation. As a proof-of-concept, Streptococcus mutans (S. mutans) bacteria were quantified in a phosphate buffered saline (PBS) buffer, achieving a limit of detection of 10 3 CFU/mL. Therefore, the proposed biosensor is an attractive candidate for the development of a simple and robust point-of-care diagnostic platform for bacteria identification, exhibiting good sensitivity, high selectivity, and excellent reproducibility.

Micronutrient deficiencies such as those of vitamin A and iron affect a third of the world's population with consequences such as night blindness, higher child mortality, anemia, poor pregnancy outcomes, and reduced work capacity. Many efforts to prevent or treat these deficiencies are hampered by the lack of adequate, accessible, and affordable diagnostic methods that can enable better targeting of interventions. In this work, we demonstrate a rapid diagnostic test and mobile enabled platform for simultaneously quantifying iron (ferritin), vitamin A (retinol-binding protein), and inflammation (C-reactive protein) status. Our approach, enabled by combining multiple florescent markers and immunoassay approaches on a single test, allows us to provide accurate quantification in 15 min even though the physiological range of the markers of interest varies over five orders of magnitude. We report sensitivities of 88%, 100%, and 80% and specificities of 97%, 100%, and 97% for iron deficiency (ferritin <15 ng/mL or 32 pmol/L), vitamin A deficiency (retinol-binding protein <14.7 µg/mL or 0.70 µmol/L) and inflammation status (C-reactive protein >3.0 µg/mL or 120 nmol/L), respectively. This technology is suitable for point-of-care use in both resource-rich and resource-limited settings and can be read either by a standard laptop computer or through our previously developed NutriPhone technology. If implemented as either a population-level screening or clinical diagnostic tool, we believe this platform can transform nutritional status assessment and monitoring globally. micronutrient deficiency diagnostics | smartphone | point-of-care diagnostics | multicolor lateral flow | fluorescence immunoassay I ron deficiency (ID) and vitamin A deficiency (VAD) are two of the most prevalent micronutrient deficiencies worldwide. ID affects 2 billion people and is a common cause of anemia , which may reduce physical work capacity in adults or lead to impaired brain development in children (1). VAD causes night blindness, mostly among children and pregnant women, affecting about 29% of the population in low-and mid-income countries (2). VAD also negatively affects the immune system and results in lowered erythropoiesis (3). Moreover, ID and VAD often coexist (4) and the interaction between ID and VAD may exacerbate each deficiency (5-7). Therefore, simultaneous access to iron and vitamin A status among populations at risk is important. ID and VAD due to dietary inadequacy can be potentially effectively treated at early stages by changing diet and/or taking supplements (8-10), although it can be challenging at the population level. Measuring ID and VAD status represents an important first step in managing these deficiencies. Ferritin and retinol-binding protein (RBP) in serum are common biomarkers used for assessment of iron and vitamin A status. Ferritin serves to store and transport iron in blood, an indicator of ID (11). The normal range of ferritin in serum is between 15 ng/mL (32 pmol/L) and 150 ng/mL (316 pmol/L) for females or 200 ng/mL (421 pmol/L) for males, while the cutoff for depleted iron storage in children less than 5 y old is <12 ng/mL (26 pmol/L) and <30 ng/mL (63 pmol/L) if inflammation presents. Nearly all retinol, the circulating form of vitamin A in serum, is bound to RBP, so RBP concentrations in blood can be used as an indicator of vitamin A status (12). However , different RBP cutoffs such as 14.5 µg/mL (0.69 µmol/L), 14.7 µg/mL (0.70 µmol/L), and 17.4 µg/mL (0.83 µmol/L) for a diagnostic of VAD have been proposed (13-16), because the molar ratio between retinol and RBP depends on many factors. For the purposes of this paper, we consider a serum RBP concentration lower than 14.7 µg/mL (0.70 µmol/L) as vitamin A deficient. This cutoff corresponds to the diagnostic standard for VAD at 0.70 µmol/L of serum retinol concentration, assuming a 1:1 retinol to RBP ratio in circulation (17), which has also been demonstrated in previous research (15, 18). A challenge to diagnosing ID and VAD, however, is that RBP and ferritin are both acute phase proteins. This means that RBP concentrations in blood can be temporarily reduced and ferritin concentrations can be temporarily increased by acute infection and inflammation (19-21). Therefore, readings taken during acute infection or inflammation periods can result in a false deficiency/sufficiency diagnosis. As such, C-reactive protein (CRP) or similar markers of inflammation should also be measured, to correctly interpret iron and vitamin A status. For people with moderate infection , serum CRP concentration is usually higher than 5.0 µg/mL Significance We demonstrate a technology that we believe could transform the way nutritional deficiency testing is done worldwide. Micronutrient deficiencies such as vitamin A and iron affect a third of the world's population with consequences such as blindness, higher child mortality, anemia, poor pregnancy outcomes, and reduced work capacity. Our testing platform simultaneously quantifies concentrations of ferritin, retinol-binding protein, and C-reactive protein, allowing one to diagnose iron and vitamin A deficiency and inflammation status (to better inform and help with the interpretation of the result) in about 15 min. Our approach combines multiple florescent markers and immunoassay approaches on a single test strip, allowing us to span the five orders of magnitude difference in the physiological range of these markers.

We demonstrate freely suspended graphene-based nanomechanical membranes (NMMs) as acoustic sensors in the audible frequency range. Simple and low-cost procedures are used to fabricate NMMs with various thicknesses based on graphene layers grown by graphite exfoliation and solution processed graphene oxide. In addition, NMMs are grafted with quantum dots (QDs) for characterizing mass sensitive vibrational properties. Thickness, roughness, deformation, deflection and emissions of NMMs with attached QDs are experimented and analyzed by utilizing atomic force microscopy, Raman spectroscopy, laser induced deflection analyzer and spectrophotometers. Förster resonance energy transfer (FRET) is experimentally achieved between the QDs attached on NMMs and nearby glass surfaces for illustrating acousto-optic utilization in future experimental implementations combining vibrational properties of NMMs with optical emission properties of QDs. This property denoted as vibrating FRET (VFRET) is previously introduced in theoretical studies while important experimental steps are for the first time achieved in this study for future VFRET implementations. The proposed modeling and experimental methodology are promising for future novel applications such as NMM based biosensing, photonics and VFRET based point-of-care (PoC) devices.

A B S T R A C T We demonstrate the fabrication of fully printed microfluidic CD4 counting chips with complete on-chip sample preparation and their applicability as a CD4 counting assay using samples from healthy donors and HIV-infected patients. CD4 counting in low-income and resource-limited point-of-care settings is only practical and affordable, if disposable tests can be fabricated at very low cost and all manual sample preparation is avoided, while operation as well as quantification is fully automated and independent of the skills of the operator. Here, we show the successful use of (inkjet) printing methods both to fabricate microfluidic cell counting chambers with controlled heights, and to deposit hydrogel layers with embedded fluorophore-labeled antibodies for on-chip sample preparation and reagent storage. The maturation process of gelatin after deposition prevents antibody wash-off during blood inflow very well, while temperature-controlled dissolution of the matrix ensures complete antibody release for immunostaining after the inflow has stopped. The prevention of antibody wash-off together with the subsequent complete antibody release guarantees a homogeneous fluorescence background, making rapid and accurate CD4 counting possible. We show the successful application of our fully printed CD4 counting chips on samples from healthy donors as well as from HIV-infected patients and find an excellent agreement between results from our method and from the gold standard, flow cytometry, in both cases.