Gelsolin (GSN) is one of actin filament-severing proteins that play a key role in the actin cytos... more Gelsolin (GSN) is one of actin filament-severing proteins that play a key role in the actin cytoskeleton rearrangement and the modification of tumor cell proliferation and metastasis. TGF-beta has ...
Quantitative polymerase chain reaction (qPCR) is the most important quantitative sensing techniqu... more Quantitative polymerase chain reaction (qPCR) is the most important quantitative sensing technique for pathogens, especially for emerging pandemics such as coronavirus outbreak this year. The qPCR chip and device were investigated to meet the unmet needs of ultrafast inspection time, high accuracy, and small system volume. Therein, the fluorescence intensity was the most important signal in qPCR quantification of DNA amplifications, which is essential not only in the confirmative diagnosis of positive or negative infection, but also in the assessment of viral load for therapeutic and quarantine decision making. As the target DNAs got amplified, the interaction of fluorescence dye and double strand DNA will generate fluorescence signal proportional to amplified DNA in the intensity when excited by certain wavelength. A miniature spectro-detector was employed to receive the fluorescence scattering for digital output of the intensity in the qPCR chip in this study, and the optical simulation and actual experimental design and results according to the optical simulation results were performed to study the effect of the stray light shutter (SLS) in the improvement of the signal in fluorescence detection. The analysis results showed that the signal-to-noise ratio (SNR) of the fluorescence can be enhanced significantly for 5 times of the control using the SLS with a shape of extended component aperture, where the protruding structure was positioned away from the center. The experimental results showed that fluorescence intensity can be enhanced by 15.50% and 9.86% when adding the above shape of SLS in resin- and in glass-based chip, respectively. The results also demonstrated that the optical setup had good stability and repeatability in fluorescence detection, and variation was less than 1.00 %. Our results can provide important reference to the development of qPCR chip to obtain the high SNR fluorescence signal in DNA quantification process.
Quantitative polymerase chain reaction (qPCR) has been widely employed for the positive or negati... more Quantitative polymerase chain reaction (qPCR) has been widely employed for the positive or negative detection of bacteria or viruses, particularly SARS-CoV-2. Fluorescence signal and cycle threshold information is critical for the positive and negative detection of target test samples in qPCR systems. To determine viral concentration, the fluorescence intensity of each cycle must be recorded using a qPCR system. In general, the time points of fluorescence excitation and excitation light intensity affect fluorescence intensity. Thus, this study proposed an effective excitation method for enhancing fluorescence intensity. Several parameters, including excitation light intensity, the excitation time point, and the reaction time of the reagent at each temperature stage, were modified in assessing fluorescence performance and determining suitable parameters for fluorescence excitation in a qPCR system. Fluorescence intensity resulted in the most optimal fluorescence performance; specifically, excitation was triggered by using a 30 mA current, and the excitation light was activated when the temperature decreased to 60 °C. Total reaction time was 1 s, and the concentrated fluorescence value and suitable cycle threshold value were obtained. Overall, high efficiency, low fluorescence decay, and high light stability were observed. The present findings demonstrate that controlling the time point of excitation light can enhance the fluorescence efficiency and performance of qPCR systems, with relevant benefits in medical diagnostics and rapid viral detection, among other applications.
This study proposes an optical method to improve the yield efficiency of QPCR. The concept is tha... more This study proposes an optical method to improve the yield efficiency of QPCR. The concept is that the conversion efficiency of fluorescent dyes is not high, and the light intensity signal is weak and difficult to distinguish. Therefore, the intensity signal of the excitation light source is reduced to obtain the fluorescent signal. Using the DNA binding dye as a model, the excitation light signals captured by the different angles between the incident light and the speculary reflected light are used to determine the correct fluorescent detection position, and to explore the efficiency of the test tube diameter for capturing fluorescent signals. The simulation results show that the standard diameter test tube has a minimum noise interference at the 45 degree position, which means that the fluorescent signal can be intercepted most effectively. This method does not change any chemical configuration and process conditions, saves a lot of time and process steps, and has high stability and zero pollution.
The fluorescence signal of Sybr Green can represent the amount of target DNA copy numbers in the ... more The fluorescence signal of Sybr Green can represent the amount of target DNA copy numbers in the samples, thereby determine a positive or negative diagnostic results after polymerase chain reaction (PCR). For precision quantification of the target gene in the sample, the fluorescent signal should be recorded in each cycle. Traditionally, highly sensitive devices such as silicon photomultipliers and high-power light source such as laser diode were used to excite and detect the fluorescence from double strand DNA selective dyes. However, the costs of these components were too high to be widely applied for rapidly on-site screening of outbreak causing pathgens in local clinics and fields of tests. In this study, low-cost optical element such as LED and photodiode were used to implementan off-plane excitation method to enhance the fluorescence signal. Several parameters such as illumination angle between LED and photodiode in horizontal direction and tilted illumination in vertical direction were optimized in the experiment to ensure the performance. The results showed that the fluorescence intensity can be enhanced approximately 25 %. These results indicated that the developed illumination architecture had advantages of low background noise, high sensitivity and high fluorescence variation. This research has successfully demonstrated an off-plane excitation method for enhancing the resolution of qPCR system and applying in medical diagnostics, rapid screening and related applications.
Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous... more Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous microhardness analyses have introduced errors due to a substrate effect, and thereby could not substantiate the early loss of these deposits. To address this question, we applied Atomic Force Microscopy (AFM) and a nano-indentation technique in this study to characterize the nano-mechanical properties and topographic structure of enamel surfaces following topical fluoride treatment. The deposits were found to have a low nano-hardness and a high nano-wear depth, which explains the early loss of calcium-fluoride-like deposits. However, a 22% increase in the fluoride concentration could still be detected on the treated enamel surface following the removal of the surface deposits, justifying the long-term effectiveness of topical fluoride treatment.
Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Nanoparticles (NPs) are ... more Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Nanoparticles (NPs) are ideal vectors to deliver analytic probes or therapeutic agents into cells and subcellular compartments. Among many nanomaterials, gold NPs is widely used as a model platform for biomedical research because of their favorable physical and chemical properties. Thus, gold NPs has been employed for various applications, especially in medicine. Through surface modification of gold NPs with functional bio-macromolecules (i.e., peptides, nucleic acids and antibodies) may improve the ability of imaging, clinical diagnostics and therapeutics. Cellular uptake of gold NPs is highly dependent on their size, shape, and surface properties. For targeted therapy, the common strategy for specific cells or cellular compartments delivery is to modify NPs with peptides or lignads. The outcome is highly dependent on the peptide sequence and cell types. Therefore, we treated CaSKi, HeLa and SiHa cervical cancer cells with different peptide-modified gold NPs for 24 hours and determined the cellular localization of the NPs from laser confocal microscopy equipped with DIC channel. We found that gold NPs modified with the nuclear localization signal (NLS) peptide from SV40 virus (GNP-PEG/SV40) accumulated around the cytoplasmic side of nuclear membrane (perinuclear accumulation) in CaSKi and HeLa carcinoma cells and translocate into nucleus in SiHa squamous cells. For adenovirus (ADV) peptide modified NPs (GNP-PEG/ADV), nuclear localization was observed in all cervical cancer cells. We then performed cell survival test (MTT assay) for various time intervals (24 to 96 hours) to identify the relationship between NPs’ distribution and cellular response. The particles exhibited perinuclear and nuclear accumulation decreased cell survival greater than cell and particles control (GNP-PEG) did. For perinuclear accumulation in HeLa cells, through annexin V/PI stain, there was no increase in apoptosis after long-term treatment with GNP-PEG/SV40 particles, but a significant increase in LC3-II expression in the GNP-PEG/SV40-treated group, suggesting activation of autophagy. On the contrary, an apoptotic cell population was found in nuclear accumulated SiHa cells. These findings suggest that different cellular distribution of NPs may link with specific death pathways. In conclusion, this study may have implications in the development of new therapeutic modality for specific cancer cells or prevention of long-term toxicities from treatment with different peptide modified NPs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 375. doi:10.1158/1538-7445.AM2011-375
Gelsolin (GSN) is one of actin filament-severing proteins that play a key role in the actin cytos... more Gelsolin (GSN) is one of actin filament-severing proteins that play a key role in the actin cytoskeleton rearrangement and the modification of tumor cell proliferation and metastasis. TGF-beta has ...
Quantitative polymerase chain reaction (qPCR) is the most important quantitative sensing techniqu... more Quantitative polymerase chain reaction (qPCR) is the most important quantitative sensing technique for pathogens, especially for emerging pandemics such as coronavirus outbreak this year. The qPCR chip and device were investigated to meet the unmet needs of ultrafast inspection time, high accuracy, and small system volume. Therein, the fluorescence intensity was the most important signal in qPCR quantification of DNA amplifications, which is essential not only in the confirmative diagnosis of positive or negative infection, but also in the assessment of viral load for therapeutic and quarantine decision making. As the target DNAs got amplified, the interaction of fluorescence dye and double strand DNA will generate fluorescence signal proportional to amplified DNA in the intensity when excited by certain wavelength. A miniature spectro-detector was employed to receive the fluorescence scattering for digital output of the intensity in the qPCR chip in this study, and the optical simulation and actual experimental design and results according to the optical simulation results were performed to study the effect of the stray light shutter (SLS) in the improvement of the signal in fluorescence detection. The analysis results showed that the signal-to-noise ratio (SNR) of the fluorescence can be enhanced significantly for 5 times of the control using the SLS with a shape of extended component aperture, where the protruding structure was positioned away from the center. The experimental results showed that fluorescence intensity can be enhanced by 15.50% and 9.86% when adding the above shape of SLS in resin- and in glass-based chip, respectively. The results also demonstrated that the optical setup had good stability and repeatability in fluorescence detection, and variation was less than 1.00 %. Our results can provide important reference to the development of qPCR chip to obtain the high SNR fluorescence signal in DNA quantification process.
Quantitative polymerase chain reaction (qPCR) has been widely employed for the positive or negati... more Quantitative polymerase chain reaction (qPCR) has been widely employed for the positive or negative detection of bacteria or viruses, particularly SARS-CoV-2. Fluorescence signal and cycle threshold information is critical for the positive and negative detection of target test samples in qPCR systems. To determine viral concentration, the fluorescence intensity of each cycle must be recorded using a qPCR system. In general, the time points of fluorescence excitation and excitation light intensity affect fluorescence intensity. Thus, this study proposed an effective excitation method for enhancing fluorescence intensity. Several parameters, including excitation light intensity, the excitation time point, and the reaction time of the reagent at each temperature stage, were modified in assessing fluorescence performance and determining suitable parameters for fluorescence excitation in a qPCR system. Fluorescence intensity resulted in the most optimal fluorescence performance; specifically, excitation was triggered by using a 30 mA current, and the excitation light was activated when the temperature decreased to 60 °C. Total reaction time was 1 s, and the concentrated fluorescence value and suitable cycle threshold value were obtained. Overall, high efficiency, low fluorescence decay, and high light stability were observed. The present findings demonstrate that controlling the time point of excitation light can enhance the fluorescence efficiency and performance of qPCR systems, with relevant benefits in medical diagnostics and rapid viral detection, among other applications.
This study proposes an optical method to improve the yield efficiency of QPCR. The concept is tha... more This study proposes an optical method to improve the yield efficiency of QPCR. The concept is that the conversion efficiency of fluorescent dyes is not high, and the light intensity signal is weak and difficult to distinguish. Therefore, the intensity signal of the excitation light source is reduced to obtain the fluorescent signal. Using the DNA binding dye as a model, the excitation light signals captured by the different angles between the incident light and the speculary reflected light are used to determine the correct fluorescent detection position, and to explore the efficiency of the test tube diameter for capturing fluorescent signals. The simulation results show that the standard diameter test tube has a minimum noise interference at the 45 degree position, which means that the fluorescent signal can be intercepted most effectively. This method does not change any chemical configuration and process conditions, saves a lot of time and process steps, and has high stability and zero pollution.
The fluorescence signal of Sybr Green can represent the amount of target DNA copy numbers in the ... more The fluorescence signal of Sybr Green can represent the amount of target DNA copy numbers in the samples, thereby determine a positive or negative diagnostic results after polymerase chain reaction (PCR). For precision quantification of the target gene in the sample, the fluorescent signal should be recorded in each cycle. Traditionally, highly sensitive devices such as silicon photomultipliers and high-power light source such as laser diode were used to excite and detect the fluorescence from double strand DNA selective dyes. However, the costs of these components were too high to be widely applied for rapidly on-site screening of outbreak causing pathgens in local clinics and fields of tests. In this study, low-cost optical element such as LED and photodiode were used to implementan off-plane excitation method to enhance the fluorescence signal. Several parameters such as illumination angle between LED and photodiode in horizontal direction and tilted illumination in vertical direction were optimized in the experiment to ensure the performance. The results showed that the fluorescence intensity can be enhanced approximately 25 %. These results indicated that the developed illumination architecture had advantages of low background noise, high sensitivity and high fluorescence variation. This research has successfully demonstrated an off-plane excitation method for enhancing the resolution of qPCR system and applying in medical diagnostics, rapid screening and related applications.
Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous... more Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous microhardness analyses have introduced errors due to a substrate effect, and thereby could not substantiate the early loss of these deposits. To address this question, we applied Atomic Force Microscopy (AFM) and a nano-indentation technique in this study to characterize the nano-mechanical properties and topographic structure of enamel surfaces following topical fluoride treatment. The deposits were found to have a low nano-hardness and a high nano-wear depth, which explains the early loss of calcium-fluoride-like deposits. However, a 22% increase in the fluoride concentration could still be detected on the treated enamel surface following the removal of the surface deposits, justifying the long-term effectiveness of topical fluoride treatment.
Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Nanoparticles (NPs) are ... more Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Nanoparticles (NPs) are ideal vectors to deliver analytic probes or therapeutic agents into cells and subcellular compartments. Among many nanomaterials, gold NPs is widely used as a model platform for biomedical research because of their favorable physical and chemical properties. Thus, gold NPs has been employed for various applications, especially in medicine. Through surface modification of gold NPs with functional bio-macromolecules (i.e., peptides, nucleic acids and antibodies) may improve the ability of imaging, clinical diagnostics and therapeutics. Cellular uptake of gold NPs is highly dependent on their size, shape, and surface properties. For targeted therapy, the common strategy for specific cells or cellular compartments delivery is to modify NPs with peptides or lignads. The outcome is highly dependent on the peptide sequence and cell types. Therefore, we treated CaSKi, HeLa and SiHa cervical cancer cells with different peptide-modified gold NPs for 24 hours and determined the cellular localization of the NPs from laser confocal microscopy equipped with DIC channel. We found that gold NPs modified with the nuclear localization signal (NLS) peptide from SV40 virus (GNP-PEG/SV40) accumulated around the cytoplasmic side of nuclear membrane (perinuclear accumulation) in CaSKi and HeLa carcinoma cells and translocate into nucleus in SiHa squamous cells. For adenovirus (ADV) peptide modified NPs (GNP-PEG/ADV), nuclear localization was observed in all cervical cancer cells. We then performed cell survival test (MTT assay) for various time intervals (24 to 96 hours) to identify the relationship between NPs’ distribution and cellular response. The particles exhibited perinuclear and nuclear accumulation decreased cell survival greater than cell and particles control (GNP-PEG) did. For perinuclear accumulation in HeLa cells, through annexin V/PI stain, there was no increase in apoptosis after long-term treatment with GNP-PEG/SV40 particles, but a significant increase in LC3-II expression in the GNP-PEG/SV40-treated group, suggesting activation of autophagy. On the contrary, an apoptotic cell population was found in nuclear accumulated SiHa cells. These findings suggest that different cellular distribution of NPs may link with specific death pathways. In conclusion, this study may have implications in the development of new therapeutic modality for specific cancer cells or prevention of long-term toxicities from treatment with different peptide modified NPs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 375. doi:10.1158/1538-7445.AM2011-375
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