RU 03. Biocompatibility of a PDMS - Coated micro - device: Bladder volume moniyoring sensor

Objective: We evaluated the biocompatibi lity of a dimethylpolysiloxane-coated micro-device which had been designed for monitoring real-time bladder volume in previous studies.

Materials and Methods: The extract assay with dimethylpolysiloxane which had been used for coating the micro-device to measure the bladder volume was performed as an in vitro cytotoxicity test. For in vivo biocompatibility testing, the inflammatory responses around the implantation site of the micro-device in subcutaneous tissue of rat were assessed by light microscope with H&E stain and fluorescence microscope with ED1 stain and von Willebrand factor stain.

Results: The averages of cell viability in dimethylpolysiloxane group were 84.6% and 82.3% at 24 h and 72 h incubation, respectively. The qualitative evaluations with light and fluorescence microscope revealed that the inflammatory changes were peaked during 2 weeks but were almost disappeared at 4 weeks after implantation of devices. The quantitative evaluations for granulation layer formation and neovascularization showed that the thickness of the layer in dimethylpolysiloxane group was peaked during 2 weeks but it came to be stabilized at 4 weeks as thin as at 2 weeks in control group, and the frequency of neovascularization was higher in dimethylpolysiloxane group than in control group but it was not increased with time.

Conclusions: The dimethylpolysiloxane-coated micro-device is thought be a reliable bio-medical device.