Buzgo, M. | Search bioRxiv

bioRxiv2023

Topical siRNA therapy of diabetic-like wound healing

Non-healing wounds are a serious complication in diabetic patients. One of the detrimental factors contributing to limited wound healing is the accumulation of metalloproteinase-9 (MMP-9) in the wound. Selective inhibition of MMP-9 is one of the established therapeutic targets for diabetic wound healing and is therefore of great interest. Here we focused on development of gene silencing system for localized delivery of antisense siRNA against MMP-9 into the wound. We have developed a functional and biocompatible wound dressing allowing controlled release of a traceable vector loaded with the target siRNA. Specifically, the dressing consists of a degradable scaffold of polymer nanofibers embedded with the vector nanosystem, polymer-coated fluorescent nanodiamonds (FNDs). The biocompatible cationic polymer shell on FNDs was designed and optimized for binding of siRNA and formation of colloidally stable FND-siRNA complexes in physiological environment. A hybrid nanofiber scaffold consisting of poly(vinyl alcohol) and poly(caprolactone) ensured continuous release of FND-siRNA complexes from the dressing. The photostable luminescence of FNDs allowed us to monitor the vector system in the wound. Our dressing was tested on murine fibroblasts and also applied to wounds in a diabetic murine model to evaluate its suitability in terms of in vivo toxicity, biological efficacy and manipulation. The treatment resulted in significant local inhibition of MMP-9 and reduction of the wound healing time. The scar formation for treated diabetic-like animals became comparable with non-treated diabetes-free mice. Our results suggest that the application of our biocompatible dressing loaded with a non-toxic vector nanosystem is an effective and promising approach in gene therapy of non-healing wounds.

bioengineering↗

bioRxiv2021

Composite solid lipid nanoparticles with hydrogel core for delivering small hydrophilic molecules to the retina: an in vitro study using ARPE-19 and 661W cells

In this study, we developed a novel solid lipid nanoparticle (SLN) formulation for drug delivery of small hydrophilic cargo to the retina. The new formulation, based on a gel core and composite shell, allowed up to two times increase in the encapsulation efficiency. The type of hydrophobic polyester used in the composite shell mixture affects the particle surface charge, colloidal stability, and cell internalization profile. We validated the SLN capability as a drug delivery system by performing encapsulation of a hydrophilic neuroprotective cyclic guanosine monophosphate analogue, previously demonstrated to hold retinoprotective properties, and the best formulation resulted in particles with size of {+/-} 250nm, anionic charge > -20 mV, and an encapsulation efficiency value of {+/-}60%, criteria that are suitable for retinal delivery. In vitro studies using ARPE-19 and 661W retinal cell lines revealed a relatively low SLN toxicity, even when high particle concentration was used. More importantly, SLN could be uptaken by the cells and the release of the hydrophilic cargo in the cytoplasm was visually demonstrated. These findings suggest that the newly developed SLN with a gel core and composite polymer/lipid shell holds all characteristics suitable for drug delivery of small hydrophilic active molecules into retinal cell.

neuroscience↗