Evaluation of biocompatibility of an experimental membrane for glucose sensors: the results of a prospective experimental controlled preclinical study involving laboratory animals

Abstract

An increase in the accuracy of monitoring of glucose concentration indicators and an increase in the running time of glucose sensors are promising directions in the field of diabetology. One of the ways to extend the lifetime of a sensor is its complete implantation excluding direct communication with the skin surface. For effective long-term functioning in the patient’s body, the surface of an implantable sensor should be highly biocompatibile: it should not induce allergic and inflammatory reactions as well as the demarcation reaction (formation of a dense connective tissue capsule). Earlier, a group of authors developed a glucose-permeable membrane and a biocompatible coating comprising a complex of nadroparin with transesterified polyethylene glycol and γ-aminopropyl triethoxysilane, which formed a protein repellent hydrogel on the membrane surface.
 Aims. To evaluate the biocompatibility of the experimental coated membrane implanted into laboratory animals.
 Methods. The experimental prospective controlled study involved 60 laboratory animals (Wistar albino rats). The animals were divided into 3 groups of 20 animals each. Animals of each group were implanted with the standard, or experimental, or experimental coated membrane. After implantation, the skin condition in the implantation area was visually assessed for 90 days. After 90 days, the tissue condition around the implant was evaluated histologically.
 Results. No serious allergic or inflammatory reactions in the implantation area were detected in all three groups of animals within 90 days of the follow-up period. In the case of the experimental coated membrane, a significantly low score was graded based on visual assessment of the skin reactions. In the histological analysis, the tissue condition in the implantation area of the coated membranes was characterized by significantly lower density of a connective tissue capsule and the presence of vascularization areas at the contact between of the membrane surface and the surrounding tissue.
 Conclusion. In experimental animals, the tested coating significantly inhibits formation of a connective tissue capsule around the implant and reduces the intensity of skin reactions after implantation. Further clinical studies of coated membranes in humans are required to verify their biocompatibility.