Aluminium Oxide Thin-Film Based In Vitro Cell-Substrate Sensing Device for Monitoring Proliferation of Myoblast Cells.

We demonstrate cell-substrate interaction on aluminium oxide thin-film in metal-insulator-metal structure followed by the change in dielectric characteristics of Al2O3 as a function of progression of cellular growth. The theoretical calculation of the fabricated biosensor reveals that the changes in the intrinsic elemental parameters are mainly attributed to the cell-induced behavioural changes.

Functional Behavior of the Primary Cortical Neuronal Cells on the Large Surface of TiO2 and SnO2 Based Biosensing Device.

In this study, we report the fabrication of poly-L-lysine (PLL) coated large surface TiO2 and SnO2 based biosensing devices to analyze the influence of the functional behaviour of primary cortical neuronal cells. Through frequency-dependent impedance study, we observed an increase in the impedance values initially most likely due to cell adhesion, proliferation and differentiation processes leading to an increase in both the single-cell mass as well as overall cellular mass; however, it got decreased eventually with the progression of various other cellular functions including neural activity, synapse formation and neuron-neuron communication. Typically, formation and regulation of the neuronal junction i.e., synapses noticeably affected the functional behaviour of the fabricated biosensing device by increasing the neuronal communication and thereby improving the flow of current by altering the thin film resistance and capacitance. Further, the neuro-electrical phenomenon is validated by fitting the experimental impedance data to an equivalent electrical circuit model. A significant shift in the Nyquist plot was also observed visually, which indicates that this alternation is primarily due to change in characteristic behaviour of the fabricated biosensing device. Hence, we anticipate that the fabricated PLL coated large surface TiO2 and SnO2 based biosensing device can serve as a promising tool to monitor the influence of the functional behaviour of neuronal cells.

Gelatin grafted poly(D,L-lactide) as an inhibitor of protein aggregation: An in vitro case study.

Amyloids are a group of proteins that are capable of forming aggregated amyloid fibrils, which is responsible for many neurodegenerative diseases including Alzheimer's disease (AD). In our previous study, synthesis and characterization of star-shaped poly(D,L-lactide)-b-gelatin (ss-pLG) have been reported. In the present work, we have extended our work to study ss-pLG against protein aggregation. To the best of our knowledge, this is the first report on the inhibition of amyloid fibrillation by protein grafted poly(D,L-lactide). Bovine serum albumin (BSA) was chosen as the model protein, which readily forms fibril under high temperature. We found that ss-pLG efficiently suppressed the fibril formation of BSA compared with gelatin (Gel), which was supported by Thioflavin T assay, circular dichroism (CD) spectroscopy and atomic force microscopy (AFM). In addition, ss-pLG significantly curtailed amyloid-induced hemolysis. We also found that incubation of ss-pLG with neuroblastoma cells (MC65) protected the cells from fibril-induced toxicity. The rescuing efficiency of ss-pLG was better than Gel, which could be attributed to the reduced lamella thickness in branched ss-pLG. These results suggest the significance of gelatin grafting, which probably allows gelatin to interact with the key residues of the amyloidogenic core of BSA effectively.

Changes in electrolyte concentrations alter the impedance during ischemia-reperfusion injury in rat brain.

OBJECTIVE: Ischemic stroke is a major cause of death and disability worldwide. Nowadays, electrical impedance spectroscopy is an emerging tool to differentiate between normal and stroke conditions. APPROACH: In this study, changes in the bio-impedance spectroscopy using a two-electrode method with varying frequencies from 100 to 35 kHz have been assessed in a model of global cerebral ischemia in anesthetized rats during normal, occlusion and reperfusion conditions. Global cerebral ischemia was induced by bilateral common carotid artery occlusion for 40 min following 40 min of reperfusion. The concentration of sodium, potassium, calcium and chloride ions in the whole rat brain was determined by electrolyte analyzer. For the interpretation of in vivo results, changes in electrical impedance with varying concentrations of sodium, potassium and calcium ions in artificial cerebrospinal fluid (aCSF) were also observed using the bio-impedance spectroscopy method. MAIN RESULTS: The in vivo bio-impedance analysis suggests that the impedance is consistently increased during occlusion as compared to the normal condition. The in vitro study revealed that the impedance escalates with an increase in the concentration of potassium and calcium ions and reduces with an increase in the concentration of sodium ions in aCSF. A further electrolyte analysis suggested that the level of sodium and chloride ions is significantly decreased and the level of calcium and potassium is significantly increased during occlusion as compared to the normal condition. SIGNIFICANCE: These findings suggest that the increase in impedance during occlusion may be due to changes in the ionic concentration of the rat brain. The above in vivo and in vitro studies successfully demonstrated and interrelated the change in impedance with corresponding changes in ionic concentration.

Alginate Bead Based Hexagonal Close Packed 3D Implant for Bone Tissue Engineering.

Success of bone tissue engineering (BTE) relies on the osteogenic microarchitecture of the biopolymeric scaffold and appropriate spatiotemporal distribution of therapeutic molecules (growth factors and drugs) inside it. However, the existing technologies have failed to address both the issues together. Keeping this perspective in mind, we have developed a novel three-dimensional (3D) implant prototype by stacking hexagonal close packed (HCP) layers of calcium alginate beads. The HCP arrangement of the beads lead to a patterned array of interconnected tetrahedral and octahedral pores of average diameter of 142.9 and 262.9 µm, respectively, inside the implant. The swelling pattern of the implants changed from isotropic to anisotropic in the z-direction in the absence of bivalent calcium ions (Ca2+) in the swelling buffer. Incubation of the implant in simulated body fluid (SBF) resulted in a 2.7-fold increase in the compressive modulus. The variation in the relaxation times as derived from the Weichert viscoelasticity model predicted a gradual increase in the interactions among the alginate molecules in the matrix. We demonstrated the tunability of the spatiotemporal drug release from the implant in a tissue mimicking porous semisolid matrix as well as in conventional drug release set up by changing the spatial coordinates of the "drug loaded depot layer" inside the implant. The therapeutic potential of the implant was confirmed against Escherichia coli using metronidazole as the model drug. Detailed analysis of cell viability, cell cycle progression, and cytoskeletal reorganization using osteoblast cells (MG-63) proved the osteoconductive nature of the implant. Expression of differentiation markers such as alkaline phosphatase, runx2, and collagen type 1 in human mesenchymal stem cell in vitro confirmed the osteogenic nature of the implant. When tested in vivo, VEGF loaded implant was found capable of inducing angiogenesis in a mice model. In conclusion, the bead based implant may find its utility in non-load-bearing BTE.