Enhanced biocompatibility of polyimide film by anti-inflammatory drug loading

Abstract

Polyimide (PI) has been used as a substructure in the electronics industry for several decades due to its excellent thermal, mechanical, and chemical properties as well as its relatively low dielectric constant. Micro-fabricated neural prosthetic devices, which are used for chronic recording and stimulation of nervous system tissues, are in the early stages of design and development. The interface between neural microelectrodes and neural tissue plays an important role in chronic in vivo recording. However, when these devices are implanted into brain tissue for long-term recording, they lose electrical connectivity due to immune response. To enhance biocompatibility of polyimidebased neural electrodes, we performed anti-inflammatory drug loading by soaking the PI in drug loaded solvent. The drug loaded PI films were subcutaneously implanted in a rat model. The biocompatibility of the PI film was analyzed using cytotoxicity assays, RT-PCR, and H&E staining. The solvent-extracted and drug loaded PI film shows better short term biocompatibility as compared to control and non-treated PI film. This anti-inflammatory drug loading method can be used to increase the biocompatibility of neural electrodes.