Artemisinin Loaded mPEG-PCL Nanoparticle Based Photosensitive Gelatin Methacrylate Hydrogels for the Treatment of Gentamicin Induced Hearing Loss

Objective: Artemisinin (ART) is a natural anti-malarial sesquiterpene lactone which has the ability to treat and activate the CLRN1 pathway to play a pivotal role in hearing loss and hair cell function. To investigate the therapeutic effect of ART in hearing loss induced by gentamicin (GM), an ART-loaded poly(ethylene glycol)-b-poly(epsilon-caprolactone) mPEG-PCL nanoparticle-based photosensitive hydrogel was developed and tested in this study. Materials and Methods: Artemisinin-loaded mPEG-PCL nanoparticles (mPEG-PCL-ART-NPs) were prepared by a double emulsion method and the formulation was optimized by an orthogonal experimental design. The particle size, zeta potential, morphology and in vitro dissolution of the mPEG-PCL-ART-NPs were well characterized. Biocompatibility of the mPEG-PCL-ART-NPs were tested on HeLa cells with an MTT assay. The photo-crosslinkable biodegradable gelatin methacrylate (GeIMA) hydrogel was prepared and its physicochemical properties (such as substitution, photocrosslinking efficiency, cell viability morphology, mechanical and swelling properties) were evaluated. Finally, mPEG-PCL-ART-FITC-NPs, loaded mPEG-PCL-ART-NPs, and loaded mPEG-PCL-ART-NPs-GelMA hydrogels were fabricated and a GM toxicity-induced guinea pig ear damage model was established to determine the effectiveness of the materials on returning auditory function and cochlea pathomorphology. Results: The zeta potential of the mPEG-PCL-ART-NPs was about -38.64 +/- 0.21 mV and the average size was 167.51 +/- 1.87 nm with an encapsulation efficacy of 81.7 +/- 1.46%. In vitro release studies showed that the mPEG-PCL-ART-NPs possessed a sustained-release effect and the MTT experiments showed good biocompatibility properties of the drug-loaded nanoparticles. The results indicated that the 5% GelMA with MA-4% hydrogel had a better crosslinking density and 3D structure for drug loading and drug delivery than controls. Skin penetration results showed that the mPEG-PCL-ART-NPs increased adhesive capacity and avoided fast diffusion in the skin. Most importantly, auditory brainstem response results indicated that the mPEG-PCL-ART-NPs-GelMA hydrogel alleviated hearing loss induced by GM. Conclusion: These results suggested that the presently fabricated mPEG-PCL-ART-NPs-GelMA hydrogels are promising formulations for the treatment of hearing loss induced by GM and lay the foundation for further clinical research of inner ear induction therapy.