Study of lubricating nanocoatings for cardiovascular catheters based on molecular self-assembly and Schiff base reactions

During cardiovascular interventional surgeries, catheters come into mechanical contact with vascular tissues, resulting in friction, collisions, and compression that can damage the tissue. To address this, surface engineering is essential for modifying the catheter surface. Effective catheter coatings require high adhesion strength to prevent peeling or delamination from the inner surface, whereas the outer surface must provide excellent lubricity and biocompatibility. In this study, we used the layer-by-layer (LbL) technique to introduce catechol-modified chitosan (CC) and dopamine-modified oxidized hyaluronic acid (DOHA), which form a nanoscale, superhydrophilic, strongly adhesive, and biocompatible coating on cardiovascular catheters. Tight binding of CC and DOHA results from electrostatic interactions, chemical reactions, and catechol group enrichment, yielding an adhesion strength of up to 1 MPa. These CC/DOHA multilayers greatly enhance the lubrication performance of the TPU substrate, reducing the coefficient of friction (COF) by up to 95% compared with that of the uncoated state. After a 30-min friction test, the COF of the CC/DOHA₁₆ coating only slightly increased from 0.032 to 0.044, demonstrating excellent stability. Evaluations revealed a reduction in vascular intima damage from grade 5 without coating to grade 3, confirming the effectiveness of the coating in minimizing friction-induced damage.