Calcium Glycerophosphate

Insufficient levels of nitric oxide may lead to chronic and acute wounds. Additionally, it is crucial that nitric oxide is prepared in a controlled-release manner due to its gaseous nature and short half-life. To address this issue, utilizing nitric oxide donors, particularly S-nitrosothiols such as S-nitrosoglutathione (GSNO), could efficiently overcome instability and aid in biomedical applications. Decellularized human amniotic membranes are also best known for their anti-inflammatory, angiogenic, and antimicrobial properties to promote wound epithelization. In this study, a novel nitric oxide-generated wound dressing based on an amniotic membrane was investigated. This construct consisted of a chitosan/β-glycerophosphate thermosensitive hydrogel covered with a decellularized human amniotic layer embedded with GSNO-loaded polylactic acid microparticles. The structure of GSNO was confirmed by spectrometric, elemental, and chemical analyses. The GSNO-loaded microparticles had a diameter of 40.66 ± 6.92 µm, and an encapsulation efficiency of 45.6 ± 6.74%. The hybrid construct and GSNO-loaded microparticles enhanced the long-term stable release of GSNO compared to free GSNO. The construct released nitric oxide ranging from 24 to 68 nM/mg during 7 days. The thermosensitive hydrogel was formed at 32.7 ± 1 °C and had a porous structure with a pore size of 41.76 ± 9.76 µm. The MTT and live/dead assays performed on human dermal fibroblast cells demonstrated suitable cell viability and adhesion to the final construct. Further, hemolysis analysis revealed less than a 5% hemolysis rate due to negligible blood cell adhesion. Overall, the prepared hybrid construct demonstrated suitable characteristics as a potential active wound dressing capable of controlled nitric oxide delivery.

The immune response dominated by macrophages plays a pivotal role in the regeneration of bone tissue. In this work, an injectable temperature-responsive hydrogel composed of geniposide-loaded mesoporous bioactive glass, chitosan and β-glycerophosphate (G-M Gel) was prepared, showing robustly networks, uniform pore structure, excellent biocompatibility, immunomodulatory effect and osteogenic potential. In an inflammatory microenvironment elicited by lipopolysaccharide (LPS), the proportion of M1 and M2 macrophages measured by flow cytometry were 33.17 % and 2.07 %, respectively. After G-M Gel treatment, the proportion of M1 macrophages decreased to 14.4 %, while the proportion of M2 macrophages increased significantly to 16.2 %. LPS treated macrophage conditioned medium inhibited the expression of osteogenic related factors (OCN, OPN, Runx2), alkaline phosphatase (ALP) and alizarin red S (ARS) in MC3T3-E1 cells. In contrast, LPS + G-M Gel treated macrophage conditioned medium significantly increased the expression of osteogenic related factors, ALP and ARS. These results demonstrated that G-M Gel can augment bone formation by promoting the polarization of M2 macrophages, showing great potential clinical application of G-M Gel in bone regeneration field.