Development of anti-fouling endoscope tip hood for gastrointestinal endoscopy

The contamination of the endoscope tip lens results in poor endoscopic imaging. To prevent the adsorption of contaminants, we applied a soft contact lens made of 2-hydroxyethyl methacrylate hydrogel to the tip of a gastrointestinal endoscope. Additionally, a novel endoscopic hood with an upper surface composed of a single layer inside the hood cavity was developed. For in vitro anti-fouling performance testing using blood, changes in light transmittance were examined with hydrogel plates and compared to conventional quartz glass and surfactant-coated glass. The transmittance changes at a wavelength of 415 nm were 1.5% for the hydrogel plate, significantly lower than 82.9% for quartz glass and 85.2% for surfactant-coated glass (p < 0.001), demonstrating the hydrogel's high anti-fouling performance. Another in vitro quantitative assay, evaluated by exposure to blood, lipid, and mucin liquids, showed high anti-fouling performance in the order hydrogel plate > surfactant-coated glass > quartz glass. Moreover, an in vivo pig model performing gastric endoscopic submucosal dissection was used to evaluate anti-fouling performance by analyzing endoscopic images with Michelson contrast. The contrast value of the upper surface group (Hydrogel) was 0.97, significantly higher than 0.62 for the non-upper surface group (Surfactant) (P < 0.001). Therefore, the novel anti-fouling endoscope tip hood could be applied in future clinical applications.