Functional Polyaniline for Optical Biosensor and Tissue Engineering Applications
Diabetes mellitus is a worldwide public health problem. A typical treatment regimen maintains blood glucose concentrations close to the normal limits <180 mg/dl and >70 mg/dl. However, the current practice of "finger-stick" testing is a significant burden on these patients. As a result, dangerous spikes or dips in blood sugar levels between tests may still go unnoticed. We have developed a novel method of polyaniline based optical glucose sensor that utilizes the unique color-shifting properties of polyaniline, a biocompatible conducting polymer, at specific wavelengths of light that can pass easily through living tissue. A facile method of reprecipitation of emeraldine base form of polyaniline nanoparticles immobilized glucose oxidase (an enzyme that is naturally produced in vivo) from an aqueous-organic suspension was utilized for sensor fabrication. We expect that the sensor specificity for glucose and overall simplicity of fabrication will make it a viable, cost-efficient alternative to the traditional amperometric enzyme-electrode based sensors.
Electrical charges play an important role in stimulating various cell types such as neurons, osteoblasts, fibroblasts by either proliferation or differentiation. Our research group synthesized self-doped electrically conducting sulfonated polyaniline (SPAN) and fabricated interdigitated electrodes (IDEs) for stimulation of pre-osteoblast cell lines. These SPAN-based IDEs were found to facilitate the growth of osteoblasts – bone marrow stromal cells (BMSCs), pre-osteoblast cells (MC3T3-E1), and human osteosarcoma (HOS) cells. Under electric field stimulation of these osteoblasts, an enhanced cell proliferation and differentiation into a more mature, bone-forming phenotype was observed in vitro. These organic electrodes have potential utility as a temporary scaffold and as an electrical signal carrier for cell stimulation in tissue engineering applications.