Colosseum Combinatorial Chemistry Centre for Technology S.r.l (C4T), Via della Ricerca Scientifica snc, 00133 Rome, Italy.
Novagenit Srl, 38017 Mezzolombardo (TN), Italy.
Biomolecules. 2020 Oct 24;10(11):1478. doi: 10.3390/biom10111478.
The stability and the degradation of polymers in physiological conditions are very important issues in biomedical applications. The copolymer of hyaluronic acid and poly-D,L-lactic acid (made available in a product called DAC) produces a hydrogel which retains the hydrophobic character of the poly-D,L-lactide sidechains and the hydrophilic character of a hyaluronic acid backbone. This hydrogel is a suitable device for the coating of orthopedic implants with structured surfaces. In fact, this gel creates a temporary barrier to bacterial adhesion by inhibiting colonization, thus preventing the formation of the biofilm and the onset of an infection. Reabsorbed in about 72 h after the implant, this hydrogel does not hinder bone growth processes. In the need to assess stability and degradation of both the hyaluronan backbone and of the polylactic chains along time and temperature, we identified NMR spectroscopy as a privileged technique for the characterization of the released species, and we applied diffusion-ordered NMR spectroscopy (DOSY-NMR) for the investigation of molecular weight dispersion. Our diffusion studies of DAC in physiological conditions provided a full understanding of the product degradation by overcoming the limitations observed in applying classical chromatography approaches by gel permeation UV.
聚合物在生理条件下的稳定性和降解是生物医学应用中非常重要的问题。透明质酸和聚-D,L-乳酸的共聚物（称为 DAC）产生一种水凝胶，保留了聚-D,L-丙交酯侧链的疏水性和透明质酸主链的亲水性。这种水凝胶是一种用于骨科植入物表面结构涂层的合适装置。事实上，这种凝胶通过抑制定植来形成临时的细菌附着障碍，从而防止生物膜的形成和感染的发生。在植入物后约 72 小时被吸收，这种水凝胶不会阻碍骨生长过程。为了评估透明质酸主链和聚乳酸链在时间和温度下的稳定性和降解情况，我们确定 NMR 光谱是一种用于表征释放物质的特殊技术，并应用扩散排序 NMR 光谱（DOSY-NMR）研究分子量分布。我们在生理条件下对 DAC 的扩散研究通过克服经典凝胶渗透 UV 色谱方法所观察到的局限性，提供了对产品降解的全面理解。
