ABSTRACT
[This corrects the article DOI: 10.1039/D2RA00311B.].
ABSTRACT
The incidence of articular cartilage defects is increasing year by year. In order to repair the cartilage tissue at the defect, scaffolds with nanofiber structure and biocompatibility have become a research hotspot. In this study, we designed and fabricated a bi-layer scaffold prepared from an upper layer of drug-dispersed gelatin methacrylate (GELMA) hydrogel and a lower layer of a drug-encapsulated coaxial fiber scaffold prepared from silk fiber (SF) and polylactic acid (PLA). These bi-layer scaffolds have porosity (91.26 ± 3.94%) sufficient to support material exchange and pore size suitable for cell culture and infiltration, as well as mechanical properties (2.65 ± 0.31 MPa) that meet the requirements of cartilage tissue engineering. The coaxial fiber structure exhibited excellent drug release properties, maintaining drug release for 14 days in PBS. In vitro experiments indicated that the scaffolds were not toxic to cells and were amenable to chondrocyte migration. Notably, the growth of cells in a bi-layer scaffold presented two states. In the hydrogel layer, cells grow through interconnected pores and take on a connective tissue-like shape. In the coaxial fiber layer, cells grow on the surface of the coaxial fiber mats and appeared tablet-like. This is similar to the structure of the functional partitions of natural cartilage tissue. Together, the bi-layer scaffold can play a positive role in cartilage regeneration, which could be a potential therapeutic choice to solve the current problems of clinical cartilage repair.
ABSTRACT
Using nerve guide conduits (NGCs) to promote the regeneration of PNI is a feasible alternative to autograft. Compared with NGCs made of single material, composite NGCs have a greater development prospect. Our previous research has confirmed that poly(D, L-lactic acid)/ß-tricalcium phosphate/hyaluronic acid/chitosan/nerve growth factor (PDLLA/ß-TCP/HA/CHS/NGF) NGCs have excellent physical and chemical properties, which can slowly release NGF and support cell adhesion and proliferation. In this study, PDLLA/ß-TCP/HA/CHS/NGF NGCs were prepared and used to bridge a 10 mm sciatic nerve defect in 200-250 g Sprague-Dawley (SD) rat to verify the performance of the NGCs in vivo. Substantial improvements in nerve regeneration were observed after using the PDLLA/ß-TCP/HA/CHS/NGF NGCs based on gross post-operation observation, triceps wet weight analysis and nerve histological assessment. In vivo studies illustrate that the PDLLA/ß-TCP/HA/CHS/NGF sustained-release NGCs can effectively promote peripheral nerve regeneration, and the effect is similar to that of autograft.
