鄰苯二酚殼聚醣-單寧酸複合水凝膠和冷凍凝膠 的抗菌和止血性質

Abstract

具備鄰苯二酚基團的水凝膠因具備強大的黏附性、內聚能力、生物相容性和止血能力，而受到生物醫學領域的關注。鄰苯二酚官能化殼聚醣有望於製備自組裝水凝膠。然而，這類水凝膠仍然存在凝膠化效率低落和膠體解構不穩定的問題。在本研究中，合成了高取代度（~28%）的鄰苯二酚殼聚醣（Chitosan-Catechol），並將CC與同樣含有鄰苯二酚官能基的單寧酸結合，形成具備自癒合能力的CC-TA水凝膠。富含鄰苯二酚的CC-TA複合水凝膠具備快速的凝膠效率和更佳的機械性質（剪切模量約110 Pa）。原位相干小角度X射線散射（SAXS）結合流變學分析得出了CC-TA水凝膠內會形成奈米尺度團簇（~20 nm）的形態特徵。這些團簇在大幅度的動態剪切壓力下會被破壞，而此現象與CC-TA水凝膠的應變依賴性相互對應。此外，該複合水凝膠具有滲透響應性和優秀的黏附性能。與此同時，透過簡單的凍融程序所製備的CC-TA複合冷凍凝膠展現了獨特的大孔結構（約200 µm）、高溶脹率（約7000%）和良好的壓縮模量（約8 kPa）。這種類海綿結構的冷凍凝膠具備製成止血棉花的潛力，並且展現了止血能力。CC-TA衍生複合物，無論是水凝膠還是冷凍凝膠形式都具有自由基清除能力、抗菌能力和細胞相容性，這些性質幫助其在進一步的生物應用中提供潛力。

Hydrogels containing catechol group have received attention in the biomedical field due to their robust adhesive/cohesive capabilities, biocompatibility, and hemostatic abilities. Catechol-functionalized chitosan holds promise for preparing self-assembly hydrogels. However, issues of inefficient gelation and instability still persist in these hydrogels. In the current study, we synthesized chitosan catechol (CC) of high catechol substitution (~28%) and combined CC with tannic acid (TA, which also contains catechol) to form self-healing CC-TA hydrogels. The catechol-enriched CC-TA composite hydrogels showed rapid gelation and mechanical reinforcement (shear modulus ~110 Pa). In situ coherent small-angle X-ray scattering (SAXS) coupled with rheometry revealed a morphological feature of nanoscale clusters (~20 nm) within CC-TA hydrogel. The clusters underwent dynamic destruction under large-amplitude oscillatory shear, corresponding with the strain-dependent and self-healing behavior of the CC-TA hydrogel. The composite hydrogel had osmotic-responsive and notable adhesive properties. Meanwhile, CC-TA composite cryogel prepared simply through freeze-thawing procedures exhibited distinctive macroporous structure (~200 µm), high water swelling ratio (~7000%), and favorable compressive modulus (~8 kPa). The sponge-like cryogel was fabricated into swabs, demonstrating hemostatic capacity. The CC-TA composites, in both hydrogel and cryogel forms, possessed ROS scavenging ability, antimicrobial activity, and cell compatibility with potentials in biological applications.