Chemical Engineering

ABSTRACT The concept of a microfluidic biosensing device based on reflective interferometric spectroscopy (RIfS) is presented in this article. The key element of the sensor is a highly ordered nanoporous structure of anodic aluminium oxide (AAO) integrated into a microfluidic chip combined with an optical fiber spectrophotometer. AAO was prepared by electrochemical anodization of aluminium using 0.3 M oxalic acid. The structural and geometrical features of the AAO porous structures were controlled to provide optimal RIfS ...

Abstract Optimisation of reflective interferometric properties of nanoporous aluminium oxide (AAO) fabricated by electrochemical anodization using different conditions is presented. The influence of structural modification of pores including the changing of pore diameters and pore depth on interference pattern was investigated. Chemical modification of pore surface such as metal deposition and nanoparticle immobilisation was additionally used to further optimise interference properties of AAO. The results of this study will be used for ...

In this report, a label-free reflectometric interference spectroscopy (RIfS) based microchip biosensor for the detection of circulating tumour cells (CTCs) is demonstrated. Highly ordered nanoporous anodic aluminium oxide (AAO) fabricated by electrochemical anodization of aluminium foil was used as the RIfS sensing platform. Biotinylated anti-EpCAM antibody that specifically binds to human cancer cells of epithelial origin such as pancreatic cancer cells (PANC-1) was covalently attached to the AAO surface through multiple surface functionalization steps. Whole blood or phosphate buffer saline spiked with low numbers of pancreatic cancer cells were successfully detected by specially designed microfluidic device incorporating an AAO RIfS sensor, without labour intensive fluorescence labelling and/or pre-enhancement process. Our results show that the developed device is capable of selectively detecting of cancer cells, within a concentrations range of 1,000 to 100,000 cells/mL, with a detection limit of < 1000 cells/mL, a response time of <5 minutes and sample volume of 50 μL of. The presented RIfS method shows considerable promise for translation to a rapid and cost-effective point-of-care diagnostic device for the detection of CTCs in patients with metastatic cancer.

Nanoporous anodic aluminum oxide (AAO) has become one of the most popular materials with potential applications in numerous areas, including molecular separation, catalysis, energy generation and storage, electronics, photonics, sensing, drug delivery, and template synthesis.

The fabrication of AAO is based on simple, cost-effective, self-ordering anodization of aluminum, which yields vertically-aligned, highly-ordered nanoporous structures. Due to its unique optical and electrochemical properties, nanoporous AAO has been extensively explored as a platform for developing inexpensive, portable sensing and biosensing devices.

This article reviews AAO-based sensing and biosensing technologies, highlighting key examples of different detection concepts and device performance. We conclude with a perspective on the exciting opportunities for further developments in this research field.

In this report, the application of a label-free reflectometric interference spectroscopy (RIfS) using nanoporous anodic aluminium oxide (AAO) to study of binding kinetics of nickel ions to self-assembled monolayers (SAMs) of nitrilotriacetic (NTA) chelates is presented. Highly ordered nanoporous AAO fabricated by electrochemical anodization of aluminium foil was used as the RIfS sensing platform.

Improving the electrochemical stability of manganese oxide/multiwalled carbon nanotubes (MnO2/MWCNTs) nanocomposites is of great importance to many electrochemical supercapacitor applications. In this study, the electrochemical properties of MnO2 filled inside the cavity of MWCNTs were investigated for the first time. The prepared nanocomposite was characterized by means of X-ray photoelectron spectroscopy (XPS), X-ray diffraction patterns (XRD), transmission electron microscopy (TEM) images, scanning electron microscopy (SEM) together with energy dispersive X-ray spectroscopy (EDX) and thermogravimetric analyses (TGA). Electrochemical characterization has been performed using cyclic voltammetry (CV), galvanostatic charging/discharging (CD) test. The TEM image, XRD analysis confirmed the high structural stability and CD test complied the high electrochemical stability of the prepared nanocomposite. Besides, MnO2/MWCNTs nanocomposite supercapacitor showed superior cycling stability in the potential range of 0-1.0V due to the filling of the electroactive material inside the tubes and retained 96% of initial capacitance even over 200 cycles.

A novel ternary nanocomposite of nickel-manganese oxides/multi-walled carbon nanotubes (NMO/MWCNTs) coated with poly (3,4-ethylenedioxythiophene)(PEDOT) was prepared by chemical oxidation method. The filling of NMO particles inside MWCNTs and the uniform coating of NMO/MWCNTs with PEDOT intensified the capacitive behavior of MWCNTs. The lowest IR drop (0.1 V) and highest specific capacitance (SC) values of 526.55 F/g of NMO/MWCNTs/PEDOT imply it as highly efficient hybrid supercapacitor materials in 6 M KOH electrolyte.

Electrode materials are the most important factors to verify the properties of the electrochemical supercapacitor. In this paper, the storage principles and characteristics of electrode materials, including carbon-based materials, transition metal oxides and conducting polymers for supercapacitors are depicted in detail. Other factors such as electrode separator and electrolyte are briefly investigated. Recently, several works are conducted on application of multiwalled carbon nanotubes (MWCNTs) and MWCNTs-based electrode materials for supercapacitors. MWCNTs serve in experimental supercapacitor electrode materials result in specific capacitance (SC) value as high as 135 Fg -1. Addition of pseudocapacitive materials such as transition metal oxides and conducting polymers in the MWCNTs results in electrochemical performance improvement (higher capacitance and conductivity). The nanocomposites of MWCNTs and pseudocapacitive materials are the most promising electrode materials for supercapacitors because of their good electrical conductivity, low cost and high mass density. © 2012 World Scientific Publishing Company.

Abstract A municipal solid waste produced in urban and rural communities is a serious pollution source of water resource in developing country. One of the main problem in treatment of organic solid waste is its non-readily biodegradability due to the complexity of organic material especially hemicellolluse. This study reports Sodium Hydroxide (NaOH) thermochemical pretreatment of rice straw as a indicators of cellulosic compound to enhance its biodegradability.

ABSTRACT A municipal solid waste produced in urban and rural communities is a serious pollution source of water resource in developing country. One of the main problem in treatment of organic solid waste is its non-readily biodegradability due to the complexity of organic material especially hemicellolluse. This study reports Sodium Hydroxide (NaOH) thermochemical pretreatment of rice straw as a indicators of cellulosic compound to enhance its biodegradability.

Abstract: Nickel-manganese oxide/Poly (3, 4-ethylenedioxythiophene)(NMO/MWCNTs/PEDOT) nanocomposites have been prepared from emulsification of as-prepared NMO/MWCNT and aqueous acetonitrile solutions of EDOT by oxidation using Ferric chloride. The uniform coating of PEODOT on NMO/MWCNTs nanocomposite was confirmed by Energy dispersive x-ray (EDX) and scanning electron microscope (SEM) images.