Regenerative Engineering of the Nail: The Development of a Novel Nano-Based Matrix

Acute traumatic nail injury treatment repair procedures are commonly conducted in emergency departments and primary care offices. Current repair methods use nail splints which are inserted within the nail root to prevent the fusion of the proximal nail fold and the matrix tissue. Splints also provide a protective barrier overlying the nail bed soft tissue during recovery periods, but uncertain prognoses (i.e., aesthetic and functional disadvantages) reveal a need for improvement in nail repair techniques [1]. In this study, we used a coaxial electrospinning method to produce hybrid poly(lactide-co-glycolide) (PLGA) (85:15) and gelatin nanofibers to mimic the fibrous nature of the nail’s extracellular matrix. Optimal conditions to yield Hybrid₁ (PLGA shell, gelatin core) and Hybrid₂ (gelatin shell, PLGA core) fibrous matrices showed average fiber diameters of 540 ± 118 nm and 2215 ± 1135 nm, respectively. Hybrid₂ nanofibrous matrices were crosslinked at 5, 15, and 25% glutaraldehyde (GA) vapor concentrations and results revealed a decrease in average fiber diameter as GA concentration increases. Nail stem cells (NSCs) were positive for stem cell markers CD90 and CD29 and NSC marker Lgr6. K15, K14, and Anpep (CD13) expression was found in proximal matrix tissue, however, consistent CD13 expression was observed when NSCs were cultured with 0 mM, 0.15 mM, and 1.87 mM of CaCl₂ conditioned media. In vitro bioactivity observation of hybrid scaffolds loaded with nail stem cells (NSCs) isolated from rat proximal matrices were viable and showed preferred attachment to Hybrid₂ matrices at 24 hours. A regenerative engineered nail matrix may aid to improve cosmetic appearance and function of injured nail organ and the development of suitable animal models for nail regeneration will allow for study of in vivo performance. Future work will evaluate subcritical nail injury models along with regenerative engineering strategies to regenerate the nail matrix in vivo.