Electrospun nanofibrous scaffold has long been studied as skin substitutes for their structural resemblance to the dermal extracellular matrix. However, packed fibrous architecture with small pore size restricts cellular infiltration into nanofibrous mat. In this article, we report highly porous, nano-/microfibrous 3D structure using polycaprolactone-chitosan emulsion and its application in skin regeneration. Under the influence of electric field, the emulsion containing encapsulated charged chitosan droplets enhances charge of the spinning solution and residual charge in the core of the deposited fiber, thereby creating core–shell, cotton-like fluffy structure with average pore size 62 μm, fiber diameter ∼1.62 μm, contact angle of 72° and 80% water uptake capacity of the scaffold. Further, differential stirring period of the specific emulsion developed compact nanofibrous membrane with nanometer ranged pore size emphasizing the role played by emulsion droplet size and the charge carried thereafter. Presence of nanofibers with high-interconnected porosity promoted efficient cellular infiltration and proliferation from initial days of cell seeding. The scaffold supported extracellular matrix protein expression and stratified epithelialization in vitro. Effective integration and attachment of scaffold with margins of a full-thickness excision wound created in a rat model with accelerated healing within 3 weeks proved the efficiency of the scaffold as skin substitute. Additionally, gradual and prolong release of acidic chitosan from the core section benefitted wound healing by lowering the pH of wound environment. Simple technique with inexpensive raw materials endorsed the scaffold as a promising off-the-shelf matrix for skin tissue regeneration.

Mimicking skin extracellular matrix hierarchy, the present work aims to develop a bilayer skin graft comprising a porous cotton-wool-like 3D layer with membranous structure of PCL-chitosan nanofibers. Emulsion electrospinning with differential stirring periods of PCL-chitosan emulsion results in development of a bilayer 3D structure with varied morphology. The electrospun membrane has fiber diameter ∼274 nm and pore size ∼1.16 μm while fluffy 3D layer has fiber diameter ∼1.62 μm and pore size ∼62 μm. The 3D layer was further coated with collagen I isolated from Cirrhinus cirrhosus fish scales to improve biofunctionality. Surface coating with collagen I resulted in bundling the fibers together, thereby increasing their average diameter to 2.80 μm and decreasing pore size to ∼45 μm. The architecture and composition of the scaffold promotes efficient cellular activity where interconnected porosity with ECM resembling collagen I coating assists cellular adhesion, infiltration, and proliferation from initial days of fibroblast seeding, while keratinocytes migrate on the surface only without infiltrating in the membranous nanofiber layer. Anatomy of the scaffold arising due to variation in pore size distribution at different layers thereby facilitates compartmentalization and prevents initial cellular transmigration. The scaffold also assists in extracellular matrix protein synthesis and keratinocyte stratification in vitro. Further, the scaffold effectively integrates and attaches with third-degree burn wound margins created in rat models and accelerates healing in comparison to standard Tegaderm dressing™. The bilayer scaffold is thus a promising, readily available, cost-effective, off-the-shelf matrix as a skin substitute.

Presence of significantly higher amount of mercury, lead, cobalt, and cadmium in gallstones may play a pivotal role as risk factors in the development of gallbladder malignancy or pre-malignancy. 'Dense deposits' of these metals in the gallstones which is the first observation, may act as crucial doses of carcinogens.

Low strength and rapid biodegradability of Acellular Dermal Matrix (ADM) restrict 37 wider clinical application as rapid cell delivery platform in situ, for management of burn 38 wounds. Herein, extracted ADM was modified by dual cross-linking approach with ionic 39 crosslinking using chitosan (CTS) and covalent cross-linking using an iodine modified 2, 5-40 dihydro-2,5-dimethoxy-furan (DHF-I) cross-linker; termed as CsADM-Cl. In addition, 41 inherent growth factors and cytokines were found to be preserved in the CsADM-Cl, 42 irrespective of ionic/covalent crosslinking. CsADM-Cl demonstrated improvement in post 43 crosslinking stiffness with decreased biodegradation rate. This hybrid crosslinked hydrogel 44 supported adhesion, proliferation, and migration of human foreskin derived fibroblasts (HFCs) 45 and keratinocytes (HKC). Also, the angiogenic potential of CsADM-Cl was manifested by 46 chick chorioallantoic membrane (CAM) assay. CsADM-Cl showed excellent antibacterial 47 activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. 48 aureus). Moreover, CsADM-Cl treated full thickness (FT) burn wounds demonstrated rapid 49 healing marked with superior angiogenesis, well-defined dermal-epidermal junctions (DEJ), 50 mature basket weave collagen deposition, and development of more pronounced secondary 51 appendages. Altogether, the bioactive CsADM-Cl hydrogel established significant clinical 52 potential to support wound healing as an apt injectable antibacterial matrix to encounter unmet 53 challenges concerning critical burn wounds.

No abstract