ABSTRACT
BACKGROUND: Glucose sensors have been extensively researched in patent studies and manufactured a tool for clinical diabetes diagnosis. Although some kinds of electrochemical enzymatic glucose sensors have been commercially successful, there is still room for improvement, in selectivity and reliability of these sensors. Because of the intrinsic disadvantages of enzymes, such as high fabrication cost and poor stability, non-enzymatic glucose sensors have recently been promoted as next generation diagnostic tool due to their relatively low cost, high stability, prompt response, and accuracy. OBJECTIVE: In this research, a novel free standing and binder free non-enzymatic electrochemical sensor was manufactured using in situ grown copper (Cu) and cobalt (Co) on a silicon (Si) substrate. METHODS: Scanning High-Energy Electron Diffraction (SHEED) and Edward deposition methods were used to synthesise the sensors. RESULTS: Morphological observations showed that Cu and Co homogeneously formed nanorod-like shapes over the Si substrate. The elemental composition and structure of the prepared sensors were identified by Reflection High-Energy Electron Diffraction (RHEED). In terms of electrochemical properties, for the enzyme-free glucose sensor, voltammograms showed that the peak currents increased when the glucose solution was injected into the electrolytic cell. The electrical relation of voltage versus current was linear, as shown in the experimental data. Another effective parameter changed the magnetic field; and the linear behaviour of the electrical resistance of Co remained unaltered. CONCLUSION: In the optimum annealing temperature, where the magnetic field increased, the properties of the samples remained constant. In other words, in the selected annealing temperature, resistance and stability of the layers increased in a significant manner.
Subject(s)
Biosensing Techniques , Cobalt/chemistry , Copper/chemistry , Glucose/analysis , Nanotubes/chemistry , Catalysis , Electrochemical Techniques , Electrodes , Microscopy, Atomic Force , Oxidation-Reduction , Patents as Topic , Silicon/chemistryABSTRACT
In this study, we present a novel chitosan-intercalated montmorillonite/poly(vinyl alcohol) (OMMT/PVA) nanofibrous mesh as a microenvironment for guiding differentiation of human dental pulp stem cells (hDPSCs) toward neuronlike cells. The OMMT was prepared through ion exchange reaction between the montmorillonite (MMT) and chitosan. The PVA solutions containing various concentrations of OMMT were electrospun to form 3D OMMT-PVA nanofibrous meshes. The biomechanical and biological characteristics of the nanofibrous meshes were evaluated by ATR-FTIR, XRD, SEM, MTT, and LDH specific activity, contact angle, and DAPI staining. They were carried out for mechanical properties, overall viability, and toxicity of the cells. The hDPSCs were seeded on the prepared scaffolds and induced with neuronal specific differentiation media at two differentiation stages (2 days at preinduction stage and 6 days at induction stage). The neural differentiation of the cells cultured on the meshes was evaluated by determining the expression of Oct-4, Nestin, NF-M, NF-H, MAP2, and ßIII-tubulin in the cells after preinduction, at induction stages by real-time PCR (RT-PCR) and immunostaining. All the synthesized nanofibers exhibited a homogeneous morphology with a favorable mechanical behavior. The population of the cells differentiated into neuronlike cells in all the experimental groups was significantly higher than that in control group. The expression level of the neuronal specific markers in the cells cultured on 5% OMMT/PVA meshes was significantly higher than the other groups. This study demonstrates the feasibility of the OMMT/PVA artificial nerve graft cultured with hDPSCs for regeneration of damaged neural tissues. These fabricated matrices may have a potential in neural tissue engineering applications.
