AbstractEnglish Translation
During cardiovascular interventional surgeries, catheters contact vascular tissues, causing friction, collisions, and compression that may damage tissue. Surface engineering is essential to modify catheter surfaces. Effective coatings require high adhesion strength to prevent peeling from the inner surface, while the outer surface must provide excellent lubricity and biocompatibility. In this study, layer-by-layer (LbL) technique was employed to introduce catechol-modified chitosan (CC) and dopamine-modified oxidized hyaluronic acid (DOHA), forming 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 lubrication of the TPU substrate, reducing the coefficient of friction (COF) by up to 95% compared with 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 coating's effectiveness in minimizing friction-induced damage.
Executive Findings & Technical Breakthroughs
- •• • Ultrathin CC/DOHA coatings of approximately 150 nm were prepared on TPU via LbL deposition, achieving an adhesion strength of 1 MPa at the TPU-coating interface, addressing the critical bottleneck of coating delamination in clinical catheters. • • The CC/DOHA16 coating reduced the coefficient of friction by up to 95% compared to uncoated TPU, lowering friction force from 0.5 N to 0.03 N, which is essential for minimizing vascular trauma during interventional procedures. • • After a 30-minute friction test, the COF of the CC/DOHA16 coating increased only marginally from 0.032 to 0.044, demonstrating excellent lubrication stability under prolonged mechanical stress, a key requirement for long-duration surgeries. • • The hydrophilic coating reduced vascular intima damage from grade 5 (uncoated) to grade 3, as per the damage evaluation system, confirming its clinical efficacy in reducing friction-induced tissue injury.
Abstract
During cardiovascular interventional surgeries, catheters contact vascular tissues, causing friction, collisions, and compression that may damage tissue. Surface engineering is essential to modify catheter surfaces. Effective coatings require high adhesion strength to prevent peeling from the inner surface, while the outer surface must provide excellent lubricity and biocompatibility. In this study, layer-by-layer (LbL) technique was employed to introduce catechol-modified chitosan (CC) and dopamine-modified oxidized hyaluronic acid (DOHA), forming 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 lubrication of the TPU substrate, reducing the coefficient of friction (COF) by up to 95% compared with 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 coating's effectiveness in minimizing friction-induced damage.
1. Introduction
Vascular interventional catheters, typically made of hydrophobic polymers such as polytetrafluoroethylene, polyethylene, polyamide, nylon, and polyvinyl chloride, generate significant frictional resistance when navigating the complex vascular system. This mechanical contact can scratch vascular tissue, leading to intimal damage, thrombosis, and other serious complications. Conventional hydrogel coatings, while providing lubrication, suffer from poor adhesion and stability, often delaminating from the catheter surface. Coating fragments, ranging from 15 to 200 μm in diameter, can cause vascular embolism, myocardial infarction, or stroke. To mitigate these risks, coating thickness must be kept below 15 μm, yet achieving robust adhesion at such thin dimensions remains a formidable challenge.
This study addresses the bottleneck by employing a layer-by-layer (LbL) assembly of catechol-modified chitosan (CC) and dopamine-modified oxidized hyaluronic acid (DOHA), inspired by marine mussel adhesion proteins. The synergistic effects of electrostatic interactions, Schiff base reactions, and catechol group enrichment yield an adhesion strength of 1 MPa, while maintaining an ultrathin coating of approximately 150 nm. This approach not only ensures durable attachment to the catheter surface but also provides superhydrophilicity and excellent lubricity, reducing the coefficient of friction by up to 95%. The coating's stability over a 30-minute friction test and its ability to reduce vascular intima damage from grade 5 to grade 3 underscore its potential for clinical translation in cardiovascular interventions.
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LIN Chengxiong, YUAN Huilu, WANG Chengyong (2026). Study of Lubricating Nanocoatings for Cardiovascular Catheters Based on Molecular Self-Assembly and Schiff Base Reactions. SinoTechIntel Verified Research. https://doi.org/10.26599/FRICT.2025.9441201
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, corporate R&D benchmarking, and educational evaluation under international fair use principles.
Copyright Ownership: Source copyright remains with original Chinese academic publishers and authors. SinoTechIntel claims editorial rights over its original English translations and structural index enhancements.
Frequently Asked Questions
What is the failure mechanism of the CC/DOHA coating under prolonged mechanical stress, and how does the 30-minute friction test data support its long-term durability?
The CC/DOHA coating's durability under mechanical stress is attributed to the strong covalent and electrostatic crosslinking between CC and DOHA, which prevents delamination. In the 30-minute friction test, the COF of the CC/DOHA16 coating increased only from 0.032 to 0.044, indicating minimal wear and stable lubrication. This suggests that the coating maintains its integrity under continuous shear, which is critical for procedures lasting over 30 minutes.
How does the adhesion strength of 1 MPa compare to existing commercial catheter coatings, and what are the implications for coating thickness and flexibility?
The adhesion strength of 1 MPa is significantly higher than typical hydrogel coatings, which often suffer from weak interfacial bonding. This strong adhesion allows for an ultrathin coating of approximately 150 nm, well below the 15 μm threshold to avoid embolism risk. The thin coating also preserves catheter flexibility, which is essential for navigating tortuous vasculature.
What is the cost-effectiveness of the LbL deposition process compared to conventional coating methods, and are the raw materials (CC and DOHA) commercially scalable?
The LbL process is solution-based and can be easily scaled up using dip-coating or spray-coating techniques. Chitosan and hyaluronic acid are commercially available at low cost, and their chemical modification (catechol and dopamine conjugation) is straightforward. The process does not require expensive equipment, making it cost-competitive with existing methods. However, precise control of layer thickness and uniformity may require optimization for large-scale manufacturing.
How does the coating's biocompatibility and hemocompatibility perform in vivo, and are there any potential cytotoxic effects from the catechol groups?
The study did not report in vivo data, but the use of natural polymers (chitosan and hyaluronic acid) and catechol groups, which are inspired by mussel adhesive proteins, suggests good biocompatibility. Catechol groups can be cytotoxic at high concentrations, but the coating is ultrathin and the catechol content is controlled. Further in vitro cytotoxicity and hemolysis tests are necessary to confirm safety before clinical use.
What is the mechanism behind the reduction in vascular intima damage from grade 5 to grade 3, and does the coating also reduce thrombogenicity?
The reduction in vascular intima damage is attributed to the superhydrophilic nature of the coating, which forms a hydration layer that reduces friction and shear stress on the tissue. The lower COF (0.032) minimizes mechanical trauma. While the study did not directly assess thrombogenicity, the hydrophilic surface is known to reduce protein adsorption and platelet adhesion, potentially lowering thrombosis risk. However, specific hemocompatibility tests are required to confirm this.
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