Natural Bletilla striata Polysaccharide-Based Hydrogels for Accelerating Hemostasis

Abstract

Most of the existing hydrogel dressings have inadequacies in mechanical performance, biological activities, compatibility, or versatility, which results in the development of rapid, green, and cost-effective approaches for hydrogels in biochemical and biomedical applications becoming a top-priority task. Herein, inspired by the inherent bioactivity, water retention properties, and biocompatibility of natural polysaccharide hydrogels, we have prepared self-healing gels. Using Bletilla striata polysaccharide (BSP), carboxymethyl chitosan (CMCS), and borax via borate ester linkages, we created hemostatic and self-healing Chinese herbal medicine hydrogels in varying concentrations (2.5%, 3.0%, and 4.0%). A rotational rheometer was used to describe the hydrogels' shape and rheological characteristics. At all concentrations, it was found that the hydrogels' elastic modulus (G') consistently and significantly outperformed their viscous modulus (G″), suggesting a robust internal structure. All of the hydrogels had cell viability levels as high as 100% and hemolysis rates below 1%, indicating the hydrogels' outstanding biocompatibility. Furthermore, the hydrogels demonstrated superior hemostatic qualities in an in vivo mouse tail amputation model, as well as in in vitro coagulation tests. The results show that the hydrogel possesses excellent self-healing properties, as well as a good biocompatibility and hemostatic performance, thus paving the way for the development of a potential hemostatic green hydrogel.

Keywords: Bletilla striata polysaccharide; borate ester bonds; hemostasis; hydrogels; natural.

Figure 1

Schematic diagram of the preparation of BSP hydrogel.

Figure 2

(a) Optical images of the hydrogel gelation; (b) FTIR spectra of BSP, CMCS, borax, and BSP hydrogel; (c) Representative SEM images of BSP hydrogels (scale bar: 100 μm).

Figure 3

(a) Macroscopic assessment of the hydrogel’s capacity for self-healing. (b) The step-strain behavior of hydrogels with high (500%) to low (1%) strains. (c) The strain sweep measurement of hydrogels at 0.1~1000% strain. (d) The dynamic frequency sweep measurements of hydrogels at 1% strain. (e) Adhesive capacity on different substrates.

Figure 4

(a–c) The viability of L929 cells cultured with BSP hydrogel extracts at 2.5%, 3.0%, and 4.0% concentrations (n = 3). (d) The corresponding live/dead staining images of these cells. Live cells are indicated by green fluorescence from Calcein-AM (AM), and dead cells are marked by red fluorescence from propidium iodide (PI).

Figure 5

(a) The hemolysis ratio of hydrogels (n = 3). (b) Hemostasis process images of hydrogels. (c) Bloodstain photographs of the mouse tail amputation model (n = 5). (d) Quantitative analysis regarding blood loss in the mouse tail model (n = 3, ** p < 0.01).