Repair of osteochondral defects mediated by double-layer scaffolds with natural osteochondral-biomimetic microenvironment and interface

Fabrication of biphasic cartilage-bone integrated scaffolds based on tissue-specific photo-crosslinkable acellular matrix hydrogels

“…Currently, photo-crosslinkable hydrogels based on tissue-specific decellularized extracellular matrix (dECM) have been considered one of the most suitable choices to fabricate biomimetic scaffolds, because of the spatiotemporal controllability of the photo-crosslinking method [ [21] , [22] , [23] , [24] , [25] , [26] ] and the accurate microenvironment biomimic of tissue-specific dECM with respect to intricate composition, architecture, and topological structure [ [27] , [28] , [29] , [30] , [31] ]. To date, photo-crosslinkable dECM-derived scaffolds have mainly focused on soft tissue and organs, such as kidney or muscle [ 30 , 31 ], and few studies have reported constructing dECM-derived photo-crosslinkable hydrogels based on hard tissue, such as cartilage or bone [ [32] , [33] , [34] , [35] ].…”

Recent development in multizonal scaffolds for osteochondral regeneration

“…3 A). The ideal structure of OC scaffolds must exhibit (i) a chondrogenic microenvironment for cartilage formation; (ii) an osteogenic microenvironment for subchondral bone regeneration; (iii) a cartilage layer – bone layer interface; (iv) a good integration with the native tissue [ 23 , 66 ]. This last point is typically facilitated by pressing fit the scaffold into the subchondral bone defect for better integration [ 18 ].…”

“…A common strategy for the design of bilayered scaffolds with both chondrogenicity and osteogenicity is to use polymers as the cartilage layer and polymer-embedded bioceramics as the bone layer [ 21 , 57 , 59 , [69] , [70] , [71] , [72] , [73] , [74] , [75] , [76] , [77] ]. Studies reported bilayered scaffolds coupling polymer-camphene [ 78 ], two different polymers [ 68 ], polymer-bioglass [ 79 ], and decellularized cartilage matrix-decalcified bone matrix [ 66 , 80 ] to promote both osteogenesis and chondrogenesis. In some cases, osteoconductive metals are used for the bone layer [ [81] , [82] , [83] , [84] , [85] ].…”

“…Guo et al [ 89 ] have also utilized a gentle pre-cross-linking strategy on a loosely cross-linked cellulose network to retain a strong integrality of a bilayered osteochondral scaffold. In the case of ECM-based bilayered scaffolds, laser drilling was an effective approach to achieve both ideal pore size and strong adhesive strength of the bilayered scaffold [ 66 , 80 ]. .…”

“…The structure and composition of the extracellular matrix (ECM) of the OC tissue vary in the superficial, transition, deep, and subchondral bone zones [ 22 ]. Creating a multilayered scaffold mimicking the structural variations appears to be a feasible approach to reproduce the spatial organization of OC tissue, and addition of corresponding growth factors and cells further generates suitable microenvironments for cartilage and subchondral bone formation [ 23 , 24 ]. Still, it remains a challenge to attain such a structure with optimal osteochondral regeneration potential.…”