**5. Conclusions**

The molecular weight of chitosan was successfully reduced using microwave treatment. LMW chitosan generated small sized nanoparticles with positive surface charge and good dispersibility with the drug embedded inside the core of nanoparticles, thus facilitating sustained drug release in vitro through the mechanism of Fickian diffusion. The vibrational spectroscopic and thermal analysis results revealed that the chitosan main structure remained unaffected with microwave treatment but physical properties like transition temperature were significantly reduced. LMW chitosan-curcumin nanoparticles (F2) exerted synergistic antibacterial activity, with no significant cytotoxicity and enabled significantly faster scratch filling as well as cell confluence within 24 h post application comparable to control and/or blank treatment. LMW chitosan-curcumin nanoparticles with added synergistic antimicrobial activity and negligible cytotoxicity may prove beneficial in efficient delivery of curcumin into skin to hasten skin tissue regeneration following burn wounds.

**Author Contributions:** Conceptualization, N.R.K., H.K. and S.-F.N.; methodology, N.R.K. and H.K.; software, H.M.B., N.R.K. and S.-F.N.; validation, H.M.B., N.R.K., and H.K.; formal analysis, H.M.B., N.R.K., M.C.I.M.A., H.K., S.-F.N.; investigation, H.M.B. and H.K.; resources, N.R.K., M.C.I.M.A. and S.-F.N.; data curation, N.R.K., writing—original draft preparation, H.M.B., N.R.K.; writing—review and editing, H.M.B., N.R.K. and S.-F.N.; visualization, N.R.K., M.C.I.M.A., H.K. and S.-F.N.; supervision, S.U.S., N.R.K., M.C.I.M.A. and S.-F.N.; project administration, N.R.K., M.C.I.M.A. and S.-F.N.; funding acquisition, S.U.S., H.M.B. and N.R.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Higher Education Commission of Pakistan, Grant Number 7493 and APC was funded partly by UKM Malaysia and partly by Higher Education Commission of Pakistan.

**Acknowledgments:** The authors acknowledge the Gomal University Pakistan, Higher Education Commission of Pakistan for facility and financial support. The authors also acknowledge the Universiti Kebangsaan Malaysia for facility support.

**Conflicts of Interest:** The authors report no possible conflict of interest in this work.
