It is generally accepted that biodegradable materials greatly influence the nearby microenvironment where cells reside; however, the range of interfacial properties has seldom been discussed due to technical bottlenecks. This study aims to depict biomaterial microenvironment boundaries by correlating interfacial H + distribution with surrounding cell behaviors. Using a disuse-related osteoporotic mouse model, we confirmed that the abnormal activated osteoclasts could be suppressed under relatively alkaline conditions. The differentiation and apatite-resorption capability of osteoclasts were "switched off" when cultured in titrated material extracts with pH values higher than 7.8. To generate a localized alkaline microenvironment, a series of borosilicates were fabricated and their interfacial H + distributions were monitored spatiotemporally by employing noninvasive microtest technology. By correlating interfacial H + distribution with osteoclast "switch on/off" behavior, the microenvironment boundary of the tested material was found to be 400 ± 50 μm, which is broader than the generally accepted value, 300 μm. Furthermore, osteoporotic mice implanted with materials with higher interfacial pH values and boarder effective ranges had lower osteoclast activities and a thicker new bone. To conclude, effective proton microenvironment boundaries of degradable biomaterials were depicted and a weak alkaline microenvironment was shown to promote regeneration of osteoporotic bones possibly by suppressing abnormal activated osteoclasts.
Bibliographical noteFunding Information:
This work was supported by grants from the National Natural Science Foundation of China (Nos 81672227, 31870956); the Strategic Priority Research Program A of the Chinese Academy of Sciences (XDA16021000); the Highlight Research of Frontier Science, the Chinese Academy of Sciences (No. QYZDB-SSW-JSC030); the Shenzhen Science and Technology Research Funding (Nos JCYJ20170413162104773, CXZZ20150401152251209, JSGG20151030140325149, JSGG20150331154931068, and CXZZ20140417113430716); the Youth Innovation Promotion Association of the CAS; Shenzhen Peacock Program (No. 110811003586331); and partially from the Hong Kong General Research Fund.
© 2019 American Chemical Society.
- biodegradable material
- bone regeneration
- interfacial pH
- microenvironment boundary