Injectable bionanocomposite hybrid scaffolds with responsive control for enhanced osteochondral tissue regeneration

Abstract

Restoration of articular hyaline cartilage within osteochondral tissue defects has been a principal target in the field of tissue engineering due to poor functional regeneration of this avascular and heterogeneous tissue following current treatment options. The major focus thus far has been in constructing implantable scaffolds, which can be readily designed to offer appropriate mechanical properties. However, the use of implantable scaffolds requires open surgery and often cannot be readily applied to defects of irregular shape. Thus, it has become of high interest to develop minimally invasive and degradable hydrogel-based materials capable of delivering and maintaining encapsulated cells in a non-toxic manner and encouraging functional tissue regeneration. This paper reports on the synthesis and characterization of a novel class of injectable, thermally and chemically dual-gelling bionanocomposite hydrogels from thermogelling macromers (TGMs) based on poly(N-isopropylacrylamide) (pNiPAAm), degradable polyamidoamine (PAMAMs) crosslinking macromers, and functional hybrid inorganic iron oxide (Fe 3 O 4 ) nanoparticles capable of responding to an external magnetic field to stimulate cell activity and control the regenerative process in situ in a spatiotemporal manner.

Injectable hydrogels and nanocomposite hydrogels for cartilage regeneration

“…In the work of Regev et al addition of albumin fibers led to reduction of gelation time by about 20%. Adedoyin et al explained reduction of gelation time as a result of covalent attachment of Fe 3 O 4 NPs to the pNiPAAm backbone. Similar observation was found in the study of carboxymethyl chitosan and oxidized chondroitin sulfate hydrogel incorporated with bovine serum albumin (BSA)‐loaded chitosan microspheres .…”

“…As an ECM of native cartilage is composed of hydrated ground substance rich in proteoglycans, which are linked to collagen fibrils, using hydrogel combined with fibers seems to be a very promising approach. 124,125,130 An investigation by Coburn et al 124 indicates that mesenchymal stem cells embedded in PCL fiber-reinforced PEGDA hydrogel produced a greater amount of proteoglycan and collagen than hydrogel alone. Moreover, their proliferation was improved as the density of fibers was increased up to 40% of dry weight.…”

“…Fabrication of injectable hybrid hydrogels. Fabrication methods of nanocomposite hydrogels are based mostly on relatively simple mixing of gel precursors with nano/microparticles powder or solution, 3,118,121,123,124,129,130,136 which, according to the authors, allows to obtain homogenous hydrogels. Additional improvement of dispersion of silica nanofibers in buffer solution using an ultrasonic bath was performed by Buchtova et al 122 A more complicated fabrication method was used in the case of hydrogel incorporated with electrospun albumin fibers.…”