Covalently tethering siRNA to hydrogels for localized, controlled release and gene silencing

Abstract

Small interfering RNA (siRNA) has found many applications in tissue regeneration and disease therapeutics. Effective and localized siRNA delivery remains challenging, reducing its therapeutic potential. Here, we report a strategy to control and prolong siRNA release by directly tethering transfection-capable siRNA to photocrosslinked dextran hydrogels. siRNA release is governed via the hydrolytic degradation of ester and/or disulfide linkages between the siRNA and hydrogels, which is independent of hydrogel degradation rate. The released siRNA is shown to be bioactive by inhibiting protein expression in green fluorescent protein–expressing HeLa cells without the need of a transfection agent. This strategy provides an excellent platform for controlling nucleic acid delivery through covalent bonds with a biomaterial and regulating cellular gene expression, which has promising potential in many biomedical applications.

Designing biomaterials for the delivery of RNA therapeutics to stimulate bone healing

“…Importantly, chemical modification of RNA for covalent bonding may impede cell internalization as observed by Nguyen et al. [ 116 ] (see Section 4.3 ). Therefore, cleavage of covalently linked RNA should ideally release the RNA in unmodified form.…”

“…However, chemical modification of RNA may impede its cellular internalization, as illustrated by Nguyen et al. [ 116 ], who covalently bound thiol end-modified siRNA to a hydrogel of mono (2-acryloyloxyethyl) succinate–modified dextran using hydrolytically cleavable β-thioether ester linkages. They demonstrated that the delivery of covalently bound siRNA was significantly slower compared to unbound siRNA lacking this thiol modification (30% vs 68% release after 24 ​h for bound and unbound siRNA, respectively).…”

Hydrogel-Based Localized Nonviral Gene Delivery in Regenerative Medicine Approaches—An Overview

“…Likewise, in an effort to control the release kinetics and preserve the activity of therapeutic biomolecules, hydrogels have been widely investigated as gene delivery systems [ 15 ]. Various hydrogels systems based on natural polymers such as alginate [ 33 , 34 , 35 , 36 , 37 , 38 , 39 ]; cellulose [ 40 ]; chitosan [ 41 , 42 , 43 , 44 ] ( Table 1 ); collagen [ 45 , 46 , 47 ]; dextran [ 48 ]; fibrin [ 17 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ]; pullulan [ 56 ] ( Table 1 ); gelatin [ 57 , 58 , 59 , 60 ]; hyaluronic acid (HA) [ 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ] ( Table 1 ); or synthetic ones as polyethylene-glycol (PEG) [ 70 , 71 , 72 , 73 ,…”

“…Similarly, controlled delivery of RNA molecules from hydrogels networks may enhance local and sustained siRNA [ 43 , 44 , 48 , 49 , 56 , 59 , 71 , 75 , 76 , 78 , 79 , 85 , 86 ] and miRNA [ 46 , 47 , 60 , 62 , 63 , 80 , 81 , 82 , 84 , 92 ] delivery limiting undesired targets [ 14 ], and protect mRNA nanoparticles from the biological environment improving their cellular access [ 17 , 58 ].…”

Nanoparticle‐mediated siRNA delivery systems for cancer therapy

“…2 Given the challenges that RNAi-based drugs would encounter, using nanoparticles as vectors is likely to reduce these obstacles, followed by enhancing cellular uptake of siRNAs and optimizing silence efficacy. 9 Therefore, this mini-review aims to briefly describe the fundamental mechanisms of RNAi machinery and provide insights on the current status on the use of nanoparticles for siRNA delivery, as well as to discuss the applications of siRNA in cancer research and clinical therapy.…”