Preparation and characterization of silk fibroin/silica thermal insulation coatings on catheters

Clinical practice of therapeutic hypothermia for neuroprotection in acute cerebral ischemia has been hindered by the warming effect on the cold infusate along the pathway, which results from the poor thermal resistance of the traditional interventional catheter. In this study, thermal insulation coatings with different spray parameters and coating suspension compositions were prepared by air-spraying on a nylon substrate for biomedical application. The surface morphology and microstructure of coatings were investigated by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Silk fibroin (SF) and hollow silica-based nanospheres (HSBNSs) were successfully sprayed on the nylon substrate. The thermal conductivity of the coating measured by a light flash apparatus was down to 0.00105 W/(m K). The tape test indicated that the coatings containing SF, HSBNSs and glyceryl had good adhesion, showing that air-spraying is a promising method to enhance the thermal insulation performance of traditional catheters for cerebral hypothermia therapy.