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.

Vascular interventional surgery is a minimally invasive treatment. This method involves introducing catheters, guidewires, and other precision instruments into the human body to locally diagnose and treat internal diseases. However, mechanical contact, such as friction, compression, and collision, inevitably occurs during the intervention process. This can cause tissue damage. Currently, mechanical damage to vascular tissues is evaluated primarily in qualitative terms, which limits accurate reflection of both the extent of tissue damage and its influencing factors. This paper specifically studies friction injury between interventional catheters and vascular tissues. This study develops the first quantification model of injury between catheters and blood vessels. The results revealed that increases in the normal force led to increased coefficients of friction (COF) and greater energy dissipation between the friction head and vascular tissue. In contrast, varying speeds produced a trend where the COF and energy dissipation first increased and then decreased. A quantitative evaluation system for vascular tissue injury was established on the basis of indicators such as endothelial cells, glycoproteins, curled tissues, and intimal thickness on the vascular surface. Using this system, damage scores and damage grades were assigned to surface injuries in friction experiments. Pearson correlation analysis revealed a strong correlation between the COF and injury score. The link between the normal load and sliding velocity was even greater than that between the friction time and injury score. These experimental results lay the foundation for quantitative mechanical damage evaluation. They enable the mapping of relationships between mechanical factors and tissue damage.