Nanotechnology-based drug delivery systems can enhance drug permeation through the skin and improve the drug stability. The biodegradability and biocompatibility of cellulose nanocrystals have made these nanoparticles good candidates to use in biomedical applications. The hyperpigmentation is a common skin disorder that could be caused by number of reasons such as sun exposure and pregnancy. Hydroquinone could inhibit the production of melanin and eliminate the discolorations of skin. This study is aimed at introducing cellulose nanocrystals as suitable carriers for drug delivery to skin. Prepared cellulose nanocrystals were characterized by dynamic light scattering and atomic force microscopy. The size of cellulose nanocrystals determined using dynamic light scattering was 301 ± 10 nm. Hydroquinone-cellulose nanocrystal complex was prepared by incubating of hydroquinone solution in cellulose nanocrystals suspension. The size of hydroquinone-cellulose nanocrystal complex determined using dynamic light scattering was 310 ± 10 nm. The hydroquinone content of the hydroquinone-cellulose complex was determined using UV/vis spectroscopy. Hydroquinone was bound to cellulose nanocrystals representing 79.3 ± 2% maximum binding efficiency when 1.1 mg hydroquinone was added to 1 mL of cellulose nanocrystals suspension (2 mg cellulose nanocrystal). The hydroquinone-cellulose nanocrystal complex showed an approximately sustained release profile of hydroquinone. Approximately, 80% of bound hydroquinone released in 4 h.

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Nanofiber-based wound dressings have attracted much attention in wound care owing to their unique properties such as high aspect ratio and three-dimensional structure. Arginine is a precursor of nitric oxide that plays an important role in the wound-healing process. Therefore, in this study, we have developed a gel which contains lignin nanofibers (Lig-NFs) that were surface modified by arginine molecules via electrostatic interaction (Arg-Lig-NF gel). The effect of pH on the amount of arginine attached on Lig-NF surface was evaluated at three different pH values-5, 6, and 7. Fourier transform infrared spectroscopy and zeta potential of Lig-NFs before and after surface modification confirmed the surface modification of Lig-NFs with arginine molecules. The optimum gel composed of uniform Arg-Lig-NFs with diameter ranging from 100 to 250 nm. There was 184.60 ± 4.85 mg arginine in each gram of optimum gel. The release of arginine from Arg-Lig-NF gel showed a sustained release manner, and about 86.28 ± 3.50% of attached arginine were released after 24 h. Moreover, the optimum gel presented suitable viscosity and spreadability for topical application. The in vivo full thickness wound-healing assay carried out in rats demonstrated that the optimum Arg-Lig-NF gel can accelerate wound closure and increase re-epithelialization, collagen deposition, and angiogenesis significantly in Arg-Lig-NF gel-treated wounds compared to Lig-NF gel and arginine solution. Overall, these findings demonstrate that Arg-Lig-NF gel can be a promising material for the future development of effective hydrocolloid wound dressings used in the treatment of acute and chronic wounds.