Gaurav Kulkarni1 Soumen Das1 Santanu Dhara1

1, School of Medical Science & Technology, IIT Kharagpur, Kharagpur, , India

In cell-based sensing, use of 2D films supporting the growing cells is an ongoing area of research. The real-time application of any biomaterial primarily requires it’s assessment concerning physical, mechanical and, biological characterizations. Impedance sensing has proved to be a low cost, label-free and, simple approach allowing real-time monitoring of cell growth. Evaluation of electrical performance of biomaterial is important for studying the bioimpedance of cell-based system in 2D biomaterial microenvironment. The detected information provides growth dynamics at the cellular level that is useful for tumour diagnosis by comparing the electrical properties of normal and cancerous cells. While gelatin based biomaterial is developed in authors’ lab for tissue engineering, a thorough investigation of different properties of this biomaterial is reported here. Gelatin is a well-studied biomaterial for its non-antigenicity, the presence of Arginyl-Glycyl-Aspartic acid (RGD) motif and, for simple processing. Dissolution resistance in cell culture medium was overcome by chemical crosslinking in 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/ N-Hydroxysuccinimide (EDC/NHS) and glutaraldehyde (GTA). The films after modification were tested using Ninhydrin assay for crosslinking index, rheological properties for change in gel strength and cytocompatibility of HaCaT cells for biocompatibility evaluation of 2D crosslinked gelatin films. AC conductivity was evaluated using dielectric constant of the material measured by capacitance method. The crosslinking index for EDC and GTA crosslinked films reached almost 80% at concentrations of about 200 mM and 50 mM respectively. Films crosslinked with GTA displayed more increase in storage modulus values compared to EDC films. The biocompatibility of EDC films was superior to GTA films due to cytotoxicity effects of GTA release. Cell proliferation rate on both types of films was slower with EDC group found to be more biocompatible than GTA. The AC conductivity for GTA films was higher than EDC films. The maximum conductivity obtained using capacitive method was 2 S.m-1. The concentrations of EDC and GTA which can be suggested for crosslinking gelatin films based on this study are 100 mM and 50 mM for cell-based sensing applications.