Silk Fibroin Dip Coating as Drug Delivery Material for Medical Devices

Abstract

In recent years, developments in medical devices have led to research in drug release mechanisms. Although important advances have been made, some critical points still exist to investigate. Regarding materials to be used for drug purposes some natural materials seem to be a biocompatible future solution. Silk fibroin (SF) is one of the proposed candidates to satisfy the needs of drug release technologies due to its biodegradability in a tunable range of time with non-toxic end products. This work aims to study the dip coating process over stainless steel and polyurethane tubes to obtain micro-coating layers for drug release purposes. The effect on the number of cycles (2, 4, and 8) and evaporation time between cycles (10, 20, and 30 seconds) was studied. The layer thickness of the coating and the degradation rate in water were analyzed. Results showed that silk fibroin coatings at the microscale can be achieved. Furthermore, a strong influence of the evaporation time over the layer thickness with a maximum decrease of 66,1% as the evaporation time increases and an increase of 63,8% as the number of cycles increases. Results showed a high degradation rate in PBS with a 70,5% of weight loss relative to the initial weight of SF degraded within 3 hours.