MediShield™ Biocompatible Coatings

For implantable / indwelling medical devices and biosensors, biofouling is a major problem that can lead to device malfunctioning, foreign body reaction, and infection. The biofouling process starts with protein binding to the surface, followed by cells attaching to the proteins on the surface. To mitigate biofouling, a hydrogel coating is used to resist protein binding, as protein binding is minimized, cell attachment is reduced as a result, and biofouling is therefore mitigated. This will allow the devices to work better and safer in vivo. Medical Surface has developed the MediShield™ Biocompatible Coatings (an innovative hydrogel coating) to effectively limit the Foreign Body Response and to significantly extend the life of implanted devices and biosensors.

The binding of host proteins to the surface of implanted medical devices is recognized to be the beginning of the biofouling process. The MediShield™ Biocompatible Coating has been specifically designed to resist protein adsorption and has significantly lower protein binding compared to traditional coated hydrogels.

The adsorption of host proteins onto the implant surface, including complement related proteins leads to an initial inflammatory response at the implant site. Monocytes and macrophages recruit other cells, resulting in the adhesion of cells to the implanted device. The MediShield™ Biocompatible Coating has been shown to resist adhesion of cells during prolonged period of contacting blood samples.

The MediShield™ Biocompatible Coating has been tested for the ability to resist bacterial adhesion. This tests were performed according to ISO 22196. Two types of bacteria were tested: S. aureus and E. coli. In both cases, no detectable bacteria were found to adhere on MediShield™ coated surface.

Biosensor coatings not only need to create an effective barrier against host cells and proteins, but also need to be permeable to host analytes that are being measured. The MediShield™ Biocompatible Coating has been shown to be highly permeable to glucose which is essential to glucose biosensor functionality. In this test, uncoated and coated dialysis membranes (3.5kD MWCO) were compared side-by-side for permeability to glucose. MediShield™ Biocompatible Coating was found to have no significant effect on the permeation of glucose across the dialysis membrane.