Dual spinneret electrospun nanofibrous/gel structure of chitosan-gelatin/chitosan-hyaluronic acid as a wound dressing: In-vitro and in-vivo studies.

Structural and compositional similarity to the natural extracellular matrix (ECM) is a main characteristic of an ideal scaffold for tissue regeneration. In order to resemble the fibrous/gel structure of skin ECM, a multicomponent scaffold was fabricated using biopolymers with structural similarity to ECM and wound healing properties i.e., chitosan (CS), gelatin (Gel) and hyaluronic acid (HA). The CS-Gel and CS-HA nanofibers were simultaneously electrospun on the collector through dual-electrospinning technique. The presence of polymers, possible interactions, and formation of polyelectrolyte complex were proven by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA). The noncomplex component of CS-HA fibers formed a gel state when the scaffold was exposed to the aqueous media, while the CS-Gel fibers reserved their fibrous structure, resulting in formation of fibrous/gel structure. The CS-Gel/CS-HA scaffold showed significantly higher cell proliferation (109%) in the first 24 h comparing with CS (90%) and CS-Gel (96%) scaffolds. Additionally, the initial cell adhesion improved by incorporation of HA. The in-vivo wound healing results in rat elucidated more wound healing capability of the CS-Gel/CS-HA scaffold in which new tissue with most similarity to the normal skin was formed.

Hyaluronic acid coated electrospun chitosan-based nanofibers prepared by simultaneous stabilizing and coating.

Chitosan (CS) and hyaluronic acid (HA) are two oppositely charged natural polysaccharides used widely for preparation of nanofibrous scaffolds for tissue engineering applications. Here, we prepared composite fibers composed of CS and HA by electrospinning and subsequent coating. In this regard, two approaches were applied for coating CS nanofibers by HA. In the first method, electrospun nanofiner was first neutralized and then coating was done (HA/CS1), while in the second approach, neutralization and coating were carried out simultaneously (HA/CS2). The overall fibrous structure of the mats was preserved after coating through both methods and there was no remarkable morphological difference between HA/CS1 and HA/CS2 samples. The presence of HA and possible interactions between CS and HA were demonstrated in both HA coated nanofibers by FTIR and thermal gravimetric analysis. However, HA/CS2 nanofibers indicated more interactions between HA and CS. Contact angel measurement revealed differences in the wettability of resultant fibers. Although both scaffolds showed high wettability, the HA/CS2 had lower wettability than HA/CS1. More importantly, there was a difference in cytocompatibility of the scaffolds. Both HA coated scaffolds showed improvement in cell proliferation. However, cell proliferation and adhesion were more when HA was coated through a direct simultaneous method.