Antibiofilm and antithrombotic hydrogel coating based on superhydrophilic zwitterionic carboxymethyl chitosan for blood-contacting devices

Abstract

Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections, thrombosis, and intimal lesions caused by surface friction. However, achieving effective prevention of both bloodstream-associated infections and thrombosis poses a challenge due to the conflicting nature of antibacterial and antithrombotic activities, specifically regarding electrostatic interactions. This study introduced a novel biocompatible hydrogel of sodium alginate and zwitterionic carboxymethyl chitosan (ZW@CMC) with antibacterial and antithrombotic activities for use in catheters. The ZW@CMC hydrogel demonstrates a superhydrophilic surface and good hygroscopic properties, which facilitate the formation of a stable hydration layer with low friction. The zwitterionic-functionalized CMC incorporates an additional negative sulfone group and increased negative charge density in the carboxyl group. This augmentation enhances electrostatic repulsion and facilitates the formation of hydration layer. This leads to exceptional prevention of blood clotting factor adhesion and inhibition of biofilm formation. Subsequently, the ZW@CMC hydrogel exhibited biocompatibility with tests of in vitro cytotoxicity, hemolysis, and catheter friction. Furthermore, in vivo tests of antithrombotic and systemic inflammation models with catheterization indicated that ZW@CMC has significant advantages for practical applications in cardiovascular-related and sepsis treatment. This study opens a new avenue for the development of chitosan-based multifunctional hydrogel for applications in blood-contacting devices.

Keywords: Antimicrobial; Blood-clotting; Hydrogel; Sepsis; Zwitterionic.

Graphical abstract

Scheme 1

(a) Comparison of the novel multifunctional ZW@CMC coating with conventional CMC coating for blood-contacting devices (Green circles, yellow triangle and red ex marks represent good, moderate, and poor, respectively). (b) Schematic illustration of the multifunctional activities of the ZW@CMC layer. (c) Optical photograph of the prepared multi-lumen PICCs, and microscopic image of the ZW@CMC coating on PICCs.

Fig. 1

(a) A schematic illustration of the synthesis procedure and hydrogel structure of ZW@CMC. (b–d) High-resolution XPS spectra of (b) C 1s, (c) N 1s, and (d) S 2p of CMC and ZW@CMC. (e) Contact angle measurement of hydrogel coatings using captive bubble method. (f) Time-dependent swelling ratio of the CMC and ZW@CMC coating. (g) Optical photograph of the water-absorption behaviors of the different catheter surfaces.

Fig. 2

(a) Microscopic fluorescence images of C2C12 myoblast cells after LIVE/DEAD cell staining. (b) Viability of C2C12 myoblast cells for different exposure times. (c) Hemolysis assay on erythrocytes with various materials (n = 3).

Fig. 3

(a) LIVE/DEAD bacterial staining assay comparing the efficiency of CMC and ZW@CMC solutions against E. coli and S. epidermidis. (b) Antimicrobial efficiencies of TPU, CMC, and ZW@CMC against E. coli and S. epidermidis (n = 3). (c) Antibiofilm activities of the TPU, CMC, and ZW@CMC coatings (green and white color represent biofilm- and non-fouling regions of the catheter surface, respectively). (d) Design of sepsis model test with systemic inflammation and antimicrobial catheter. (e) Complete blood count results and (f) flow cytometry and cell sorting results of the systemic inflammation model. (g) Bacterial counts of bacteremia blood after a day of sepsis model test (n = 3).

Fig. 4

(a) Fibrinogen adhesion on TPU, CMC-, and ZW@CMC-coated surfaces. (b) Relative extent of fibrinogen adhesion on different surfaces. (c) Surface potential measurement of the different surfaces using a Kelvin probe force microscope. (d) The molecular electrostatic potential map of CMC and ZW@CMC calculated using Gaussian 09 quantum mechanical calculation. Platelet adhesion test of (e) platelet and (f) activated platelet on the different surfaces (n = 3). Comparison of (g) activated partial prothrombin time (APTT) and (h) prothrombin time (PT) of plasma (control), CMC- and ZW@CMC-coated surfaces (n = 4). (i) Adhesion of clotting factor-active human plasma on different surfaces. (j) Optical images of blood adhesion on the different surfaces of PICCs. (k) SEM images of the in vitro antithrombosis test of citrated sheep whole blood against different surfaces.

Fig. 5

In vivo assessment of the catheter antithrombotic performance. (a) Photographic image of the catheterization in femoral vena cava implantation model of rat. (b) Photographic images of the extracted catheters after 1 week of catheterization. (c) Weight of blood clots on the catheter surfaces in femoral vena cava implantation model after 1 week (n = 3). (d) SEM images of blood clots on the surfaces of the catheters.

Fig. 6

(a) Photograph of the interventional devices testing equipment (IDTE) used to carry out the catheter friction test, with the passage of a standard template (ASTM F2394-07). (b) Results of the catheter friction test conducted with the IDTE. (c) Photograph of the artificial cardiovascular system model employed for simulating peripherally inserted central catheterization, during the catheter friction test. (d) Results of the peripherally inserted central catheterization simulation test. (e) Photograph of the wet friction test system. (f) Results of the cyclic wet friction test.