A Facile Fabrication of a Potentiometric Arrayed Glucose Biosensor Based on Nafion-GOx/GO/AZO.

In this study, the potentiometric arrayed glucose biosensors, which were based on zinc oxide (ZnO) or aluminum-doped zinc oxide (AZO) sensing membranes, were fabricated by using screen-printing technology and a sputtering system, and graphene oxide (GO) and Nafion-glucose oxidase (GOx) were used to modify sensing membranes by using the drop-coating method. Next, the material properties were characterized by using a Raman spectrometer, a field-emission scanning electron microscope (FE-SEM), and a scanning probe microscope (SPM). The sensing characteristics of the glucose biosensors were measured by using the voltage-time (V-T) measurement system. Finally, electrochemical impedance spectroscopy (EIS) was conducted to analyze their charge transfer abilities. The results indicated that the average sensitivity of the glucose biosensor based on Nafion-GOx/GO/AZO was apparently higher than that of the glucose biosensor based on Nafion-GOx/GO/ZnO. In addition, the glucose biosensor based on Nafion-GOx/GO/AZO exhibited an excellent average sensitivity of 15.44 mV/mM and linearity of 0.997 over a narrow range of glucose concentration range, a response time of 26 s, a limit of detection (LOD) of 1.89 mM, and good reproducibility. In terms of the reversibility and stability, the hysteresis voltages (VH) were 3.96 mV and 2.42 mV. Additionally, the glucose biosensor also showed good anti-inference ability and reproducibility. According to these results, it is demonstrated that AZO is a promising material, which could be used to develop a reliable, simple, and low-cost potentiometric glucose biosensor.

The Analysis of the Urea Biosensors Using Different Sensing Matrices via Wireless Measurement System & Microfluidic Measurement System.

Two types of urea biosensors were integrated with a wireless measurement system and microfluidic measurement system. The two biosensors used were (i) a magnetic beads (MBs)-urease/graphene oxide (GO)/titanium dioxide (TiO2)-based biosensor and (ii) an MBs-urease/GO/ nickel oxide (NiO)-based biosensor, respectively. The wireless measurement system work exhibited the feasibility for the remote detection of urea, but it will require refinement and modification to improve stability and precision. The microchannel fluidic system showed the measurement reliability. The sensing properties of urea biosensors at different flow rates were investigated. From the measurement results, the decay of average sensitivity may be attributed to the induced vortex-induced vibrations (VIV) at the high flow rate. In the aspect of wireless monitoring, the average sensitivity of the urea biosensor based on MBs-urease/GO/NiO was 4.780 mV/(mg/dl) and with the linearity of 0.938. In the aspect of measurement under dynamic conditions, the average sensitivity of the urea biosensor based on MBs-urease/GO/NiO were 5.582 mV/(mg/dl) and with the linearity of 0.959. Both measurements performed NiO was better than TiO2 according to the comparisons.

The preparation and characterization of highly aligned poly(epsilon-caprolactone)/poly ethylene oxide/chitosan ultrafine fiber for the application to tissue scaffold.

The purpose of this study was to fabricate poly(epsilon-caprolactone) (PCL)/poly ethylene oxid (PEO)/chitosan (CS) ultrafine fiber in both aligned and random structures using electrospinning technique and their process parameters were optimized. The aligned and random PCL/PEO/chitosan ultrafine fibers were also used as scaffold for tissue engineering and their cell affinity was investigated. In the first part, we inspected the effect of environment conditions, solution properties, process parameters on PCL/PEO/chitosan ultrafine fiber. In the second part, the apparatus of electrospinning to manufacture highly aligned PCL/PEO/chitosan ultrafine fiber was developed. The effects of process parameters such as flow rate, design of collector and rotation speed of collecting drum on the morphology of ultrafine fiber were discussed. In addition, the cross link of PCL/PEO/chitosan ultrafine fiber by cross-linking agent was examined, too. The physical properties, chemical properties, and cell affinities of the aligned PCL/PEO/chitosan ultrafine fiber with or without cross link were measured. The chemical analysis and tensile strength of the ultrafine fiber were characterized using Fourier Transfer Infared Spectrophotometer and Universal Tensile Machine, respectively. The results show that the aligned PCL/PEO/chitosan ultrafine fibrous mat had the capacity to induce cellular alignment and enhance cellular elongation.

Creation of Chitosan-Based Nanocapsule-in-Nanofiber Structures for Hydrophobic/Hydrophilic Drug Co-Delivery and Their Dressing Applications in Diabetic Wounds.

Nanofiber meshes (NFMs) loaded with therapeutic agents are very often employed to treat hard-to-heal wounds such as diabetic wounds. However, most of the NFMs have limited capability to load multiple or hydrophilicity distinctive-therapeutic agents. The therapy strategy is therefore significantly hampered. To tackle the innate drawback associated with the drug loading versatility, a chitosan-based nanocapsule-in-nanofiber (NC-in-NF) structural NFM system is developed for simultaneous loading of hydrophobic and hydrophilic drugs. Oleic acid-modified chitosan is first converted into NCs by the developed mini-emulsion interfacial cross-linking procedure, followed by loading a hydrophobic anti-inflammatory agent Curcumin (Cur) into the NCs. Sequentially, the Cur-loaded NCs are successfully introduced into reductant-responsive maleoyl functional chitosan/polyvinyl alcohol NFMs containing a hydrophilic antibiotic Tetracycline hydrochloride. Having a co-loading capability for hydrophilicity distinctive agents, biocompatibility, and a controlled release property, the resulting NFMs have demonstrated the efficacy on promoting wound healing either in normal or diabetic rats.

Preparation of uniaxially aligned TiO2 ultrafine fibers by electrospinning.

TiO2 nanofibers are often produced by electrospinning using a collector consisting of two parallel electrodes. In this work, a high speed rotating drum was used as a collector to produce uniaxially aligned TiO2 ultrafine fibers. The apparatus to manufacture uniaxially aligned TiO2 ultrafine fiber consisted of a high-speed roller, a high-voltage power supply, a controllable syringe pump and a syringe. Titanium (IV) isopropoxide and polyvinylpyrrolidone were used as precursor and auxiliary, respectively. Titanium (IV) isopropoxide and polyvinylpyrrolidone were well mixed with other essential reagents to form the polymer solution. The polymer solution was poured into the syringe and pumped at various flow rates. The electrospun ultrafine fibers collected on the roller were heat treated up to 600 degrees C and the uniaxially aligned TiO2 ultrafine fibers were formed and characterized using scanning electron microscope and X-ray diffraction.

Fabrication and Characterization of Nylon 66/PAN Nanofibrous Film Used as Separator of Lithium-Ion Battery.

In recent years, portable electronic devices have flourished, and the safety of lithium batteries has received increasing attention. In this study, nanofibers were prepared by electrospinning using different ratios of nylon 66/polyacrylonitrile (PAN), and their properties were studied and compared with commercial PP separators. The experimental results show that the addition of PAN in nylon 66/PAN nanofibrous film used as separator of lithium-ion battery can enhance the porosity up to 85%. There is also no significant shrinkage in the shrinkage test, and the thermal dimensional stability is good. When the Li/LiFePO4 lithium battery is prepared by nylon 66/PAN nanofibrous film used as separator, the capacitor can be maintained at 140 mAhg-1 after 20 cycles at 0.1 C, and the coulombic efficiency is still maintained at 99%, which has excellent electrochemical performance.

Investigation of Flexible Arrayed Lactate Biosensor Based on Copper Doped Zinc Oxide Films Modified by Iron-Platinum Nanoparticles.

Potentiometric biosensors based on flexible arrayed silver paste electrode and copper-doped zinc oxide sensing film modified by iron-platinum nanoparticles (FePt NPs) are designed and manufactured to detect lactate in human. The sensing film is made of copper-doped zinc oxide (CZO) by a radio frequency (RF) sputtering system, and then modified by iron-platinum nanoparticles (FePt NPs). The surface morphology of copper-doped zinc oxide (CZO) is analyzed by scanning electron microscope (SEM). FePt NPs are analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The average sensitivity, response time, and interference effect of the lactate biosensors are analyzed by voltage-time (V-T) measurement system. The electrochemical impedance is analyzed by electrochemical impedance spectroscopy (EIS). The average sensitivity and linearity over the concentration range 0.2-5 mM are 25.32 mV/mM and 0.977 mV/mM, respectively. The response time of the lactate biosensor is 16 s, with excellent selectivity.

Preparation and characterization of acrylic bone cement with high drug release.

Drug-loaded bone cement is used as an application method to prevent and treat prosthesis-related infection. Despite the commercial availability of drug-loaded bone cement, low release rate of drugs from drug-loaded bone cement may result in the emergence of drug-resistant coagulase-negative staphylococci in subsequent deep infection. This work presents a method to control and increase both the drug release rate and total release amounts of drugs for drug-loaded bone cement without losing the mechanical properties of cement. A novel drug-loaded bone cement is also developed by introducing cross-linked poly(methylmethacrylate-acrylic acid sodium salt) particles into bone cement. Capable of increasing the hydrophilicity of the cement and allowing fluids to pass into the cement, the bone cement developed here supplements both the drug release rate and total release amounts of drugs.