Envoy mpd 5f catheter

The thermal resistance of the coatings with different thickness was initially evaluated by using a customized rectangular constant temperature water bath to screen out the optimized coating thickness. The Cordis Envoy® MPD 5F catheter was used as the control group. As illustrated in Fig. S1, the cold saline at 4 °C was pumped into interventional catheter soaked in 37 °C water baths. Saline was pumped with infusion rate of 20, 25, 30, 35, 40 mL/min into catheter. The length of catheter immersed into water bath was around 850 mm. The size of water bath is 600 mm in length, 340 mm in width and 260 mm in height. The variation of temperature at inlet and outlet of catheter was monitored by Applent multi-channel temperature meter AT4204 (Changzhou, Jiangsu).
After that, the resulting optimized catheter (TIC-P) and the control group were further analyzed through an in vitro artificial circulatory system. This equipment consists of a pulse pump, a temperature control water tank and transparent artificial blood vessels that 1:1 3D printed using silica gel (Fig. S2). The vascular models were filled with 5L/min simulated blood (56% glycerin and 44% DI water, 37 °C) and the 4 °C saline as infusate was injected into this circulatory system through the catheter by an infusion pump at different flow rates of 10–50 mL/min.

The LiBr, Na₂CO₃, SiO₂, NaOH, NaNO₃, H₃BO₃, dopamine hydrochloride and Tris-HCl buffer solution were purchased from Aladdin Co. Ltd (Shanghai, China). Nylon (PA66) plate, bombyx mori cocoons were purchased from Puhui Zhiyuan Co. Ltd (Beijing, China). The Spray gun (KHOKIA W-71) was used for spray coating. The Cordis Envoy® MPD 5F catheter was utilized as substrate for coatings that used for in vitro and in vivo animal studies.

Materials for spray coating were obtained by adding 1.5 g HSBP and 1 ml glycerol into 10 ml 2 wt% silk fibroin solution. The mixture was then stirred for 15min and filtered to remove denatured silk fibroin, followed by pouring into spray gun. Before the coating process, the PA66 substrates were ultrasonically washed in 70% alcohol and deionized water for 15 min. Both of the PA66 substrates and Cordis Envoy® MPD 5F catheter were surface-activated by immersion into 2 mg/mL dopamine hydrochloride solution in 10 mM Tris buffer (pH = 8.5) for 24 h at room temperature. For better atomization, the spraying pressure was selected as 0.7 MPa and Khokia W-71 spray gun was utilized. To control the spray parameter precisely, a customized rail and a rotor were made to deliver a constant spray distance at 35 cm and sweep speed of 35 mm/s. Rotational speed of rotor was controlled at 200 rpm. These silk fibroin and HSBP nanocomposite coatings were denoted as TIC (thermal insulation coatings). To further enhance the biocompatibility and integrity of the thermal insulation coating, the resulting samples were further coated by parylene-C using chemical vapor deposition method with the assistance from Zasen Nano tech Co. Ltd (Kun Shan, China) and denoted as TIC-P (parylene-C modified thermal insulation coatings).