Biodegradable and Mechanically Resilient Recombinant Collagen/PEG/Catechol Cryogel Hemostat for Deep Non-Compressible Hemorrhage and Wound Healing

Abstract

Traumatic non-compressible hemorrhage and subsequent wound management remain critical challenges in military and civilian settings to this day. Cryogels have emerged as promising hemostatic materials for non-compressible hemorrhage due to their blood-triggered shape recovery. In this study, a biodegradable and mechanically resilient cryogel (CF/PD) was produced via cryopolymerization, employing methacrylated recombinant collagen as a macromolecular crosslinker alongside poly (ethylene glycol) diacrylate (PEGDA) and dopamine methacrylate (DMA). With its interpenetrating macro-porous structure and high hydrophilicity, the CF/PD rapidly absorbs blood and returns to its original shape within 1.5 s. In a rat liver defect model, CF/PD outperformed commercially available gelatin sponges, reducing hemostasis time by 74.4% and blood loss by 76.5%. Moreover, CF/PD cryogels facilitate in situ tissue regeneration by virtue of the bioactivity and degradability of recombinant collagen. This work establishes a bioactive recombinant collagen-driven cryogel platform, offering a transformative solution for managing non-compressible hemorrhage while enabling tissue regeneration.

Keywords: cryogel; hemostasis; recombinant collagen CF-1552; shape memory recovery; wound healing.

Scheme 1

The preparation of CF/PD cryogel for non-compressible hemorrhage.

Figure 1

(a) Recombinant collagen CF-1552 modification with glycidyl methacrylate; (b) chemical reactions during the formation of CF/PD cryogel; (c) FT-IR of CF-1552, CFGMA, and CF/PD. CF/PD cryogels: (d) swelling ratio (*, p < 0.05); (e) PBS absorption ratio; (f) the dry form and the form at swelling equilibrium; (g) time of recovery (T_r) and ratio of recovery (R_r) of cryogels in PBS/blood.

Figure 2

(a) Compression recovery cycle for the cryogels; (b) compression stress–strain curve at 80% compression of the cryogels; (c) percentage of recovery for the cryogels after 10th cyclic (**, p < 0.01, ***, p < 0.001); Compression curves at 80%: (d) CF−2/PD; (e) CF-3/PD; (f) CF-4/PD; (g) SEM results of the cryogels in its original, compressed, and recovered states, scale: 200 μm; (h) scatter plot of the pore size distribution of the cryogels; (i) porosity ratio of cryogels.

Figure 3

(a) Hemolysis ratio of the cryogels; (b) Sample diagram of hemolysis experiment; (c) Cellviability ratio of the cryogels at 24 h, 48 h, and 72 h (**, p < 0.01, ***, p < 0.001); (d) results of AO/EB staining of the cryogels, scale: 200 μm; liver implantation experiment in SD rats; (e) liver function tests on day 7; (f) H&E staining results of the liver implanted for 3rd and 7th day, scale: 1000 μm (left) 100 μm (right).

Figure 4

Coagulation experiment at 60s: (a) sample diagram; (b) blood coagulation index (BCI); (c) red blood cell adhesion; (d) platelet adhesion (*, p < 0.05, **, p < 0.01, ***, p < 0.001); (e) SEM of red blood cell and platelet adhesion; scale: 10 μm; (f) changes in prothrombin time (PT) and activated partial thromboplastin time (TT) in platelet plasma from rabbits with CF-3/PD and CF-4/PD; (g) fibrinogen (FIB) adsorption ratio; (h) schematic diagram of coagulation mechanisms of CF/PD cryogels.

Figure 5

Rat liver cylindrical injury model: (a) experimental schematic diagram; (b) hemostasis time; (c) blood loss volume (*, p < 0.05, ***, p < 0.001); (d) photograph of material removal after hemostasis in a rat liver cylindrical defect model.

Figure 6

(a) Wound healing experimental diagram; (b) wound shrinkage indentation plots; (c) wound area shrinkage graph; (d) H&E staining plots; (e) Masson staining; the scale bars in (d) and (e): 1000 μm. Statistical results of epithelial widths in the skin wound healing model for the control, gauze, gelatin, CF-3/PD, CF-4/PD: (f) 7th day; (g) 11th day (*, p < 0.05, ***, p < 0.001).

Figure 7

(a) In vitro degradation; (b) in vivo degradation.