Redox‐Responsive Resilin‐Like Hydrogels for Tissue Engineering and Drug Delivery Applications

Abstract

Resilin, a protein found in insect cuticles, is renowned for its outstanding elastomeric properties. The authors' laboratory previously developed a recombinant protein, which consisted of consensus resilin‐like repeats from Anopheles gambiae, and demonstrated its potential in cartilage and vascular engineering. To broaden the versatility of the resilin‐like protein, this study utilizes a cleavable crosslinker, which contains a disulfide bond, to develop smart resilin‐like hydrogels that are redox‐responsive. The hydrogels exhibit a porous structure and a stable storage modulus (G′) of ≈3 kPa. NIH/3T3 fibroblasts cultured on hydrogels for 24 h have a high viability (>95%). In addition, the redox‐responsive hydrogels show significant degradation in a reducing environment (10 mm glutathione (GSH)). The release profiles of fluorescently labeled dextrans encapsulated within the hydrogels are assessed in vitro. For dextran that is estimated to be larger than the mesh size of the gel, faster release is observed in the presence of reducing agents due to degradation of the hydrogel networks. These studies thus demonstrate the potential of using these smart hydrogels in a variety of applications ranging from scaffolds for tissue engineering to drug delivery systems that target the intracellular reductive environments of tumors.

Resilin-mimetics as a smart biomaterial platform for biomedical applications

“… RLP 12 -RGD 2 -MMP-HBD, RLP 12 -RGD, RLP 12 -HBD, RLP 12 -MMP Cell-binding sequence (RGD), matrix metalloproteinase cleavable peptide (MMP), heparin-binding domain (HBD) Increase in cellular adhesion, biodegradation and metabolic activity (with no inflammatory response), and mechanical property Tissue engineering 17 , 63 , 64 REC or RLP 4 -ELP 7 -CLP 2 Elastin-like polypeptide (ELP), collagen-like polypeptide (CLP) Self-assembled network of flexible often aligned fibres (different to that of the twisted rope-helical structure) at physiological temperature Tissue engineering 41 An X -EGFP (where X = 4, 8, 16 and 32) Enhanced green fluorescence protein (EGFP) Autofluorescence. Bioimaging 42 RZ 10 -RGD, RZ 10 -BMP2, RZ 10 -QK Cell-binding sequence (RGD), bone morphogenetic peptide (BMP), vascular endothelial growth factor-mimicking domain (QK) Increase in cellular adhesion and differentiation, and mechanical property Tissue engineering 44 , 67 – 70 RLP n -SLP n (where n = 1, 4 and 8) Silk-like polypeptide (SLP) Spherical micelle (SLP core) to nanofibril to large coalescence with increase in temperature. Upshift in UCST and stiffness of hydrogel with increase in RLP length.…”

“…Conversely, hydrogels fabricated from RZ 10 -QK showed increased endothelial-specific markers and endothelial function and suggested that protein-engineered microenvironments are sufficient to promote endothelial differentiation in the absence of exogenous growth factors 68 . Recently, RZ 10 -RGD hydrogels were also fabricated using a redox-responsive crosslinker, 3,3′-dithiobis(sulfosuccinimidyl propionate) (DTSSP), which showed excellent NIH-3T3 fibroblast viability and proliferation, and potential in vitro degradation and drug (dextran) delivery applications 70 . However, the modular RLP hydrogels crosslinked with DTSSP exhibited shear storage modulus lower than the hydrogels crosslinked using THP 44 and TGase 69 .…”

“…The advantages of fusing therapeutic peptide to RLP-based carriers have the potential for a local therapy with improved delivery efficiency due to their temperature sensitivity and ability to self-assemble. Recently, Liu and co-workers 70 demonstrated the potential of using these smart hydrogels in a variety of applications ranging from scaffolds for tissue engineering to drug-delivery systems that target the intracellular reductive environments of tumours using redox-responsive hydrogels. RLP gels could be also tailored as nitric oxide (NO)-scavenging gel with NO-cleavable crosslinker, which has potential as a therapeutic material for various chronic inflammatory disorders (e.g, rheumatoid arthritis) when NO levels are upregulated for a long time 91 .…”

Recent trends in protein and peptide-based biomaterials for advanced drug delivery

“…Taking advantage of the recombinant nature of RLPs, Su et al engineered their novel RZ10-RGD hydrogel to respond to changes in redox [ 395 ]. They used 3,3′-dithiobis(sulfosuccinimidyl propionate) (DTSSP), a redox-responsive crosslinker, to create RLP hydrogels that degrade in a reducing environment ( Fig.…”

“…In non-reducing conditions, release rate decreased with an increase in dextran MW ( Fig. 22 B) [ 395 ]. The redox-responsiveness of this novel hydrogel makes it a promising candidate for tumor-specific drug delivery.…”