Platelet rich fibrin and simvastatin-loaded pectin-based 3D printed-electrospun bilayer scaffold for skin tissue regeneration.

Designing multifunctional wound dressings is a prerequisite to prevent infection and stimulate healing. In this study, a bilayer scaffold (BS) with a top layer (TL) comprising 3D printed pectin/polyacrylic acid/platelet rich fibrin hydrogel (Pec/PAA/PRF) and a bottom nanofibrous layer (NL) containing Pec/PAA/simvastatin (SIM) was produced. The biodegradable and biocompatible polymers Pec and PAA were cross-linked to form hydrogels via Ca2+ activation through galacturonate linkage and chelation, respectively. PRF as an autologous growth factor (GF) source and SIM together augmented angiogenesis and neovascularization. Because of 3D printing, the BS possessed a uniform distribution of PRF in TL and an average fiber diameter of 96.71 ± 18.14 nm was obtained in NL. The Young's modulus of BS was recorded as 6.02 ± 0.31 MPa and its elongation at break was measured as 30.16 ± 2.70 %. The wound dressing gradually released growth factors over 7 days of investigation. Furthermore, the BS significantly outperformed other groups in increasing cell viability and in vivo wound closure rate (95.80 ± 3.47 % after 14 days). Wounds covered with BS healed faster with more collagen deposition and re-epithelialization. The results demonstrate that the BS can be a potential remedy for skin tissue regeneration.

Core-shell nanofibers containing L-arginine stimulates angiogenesis and full thickness dermal wound repair.

Despite the advances in medicine, wound healing is still challenging and piques the interest of biomedical engineers to design effective wound dressings using natural and artificial polymers. In present study, coaxial electrospinning was employed to fabricate core-shell nanofiber-based wound dressing, with core composed of polyacrylamide (PAAm) and shell comprising 0.5 % solution of L-Arginine (L-Arg) in aloe vera and keratin (AloKr). Aloe vera and keratin were added as natural polymers to promote angiogenesis, reduce inflammation, and provide antibacterial activity, whereas PAAm in core was used to improve the tensile properties of the wound dressing. Moreover, L-Arg was incorporated in shell to promote angiogenesis and collagen synthesis. The fiber diameter of PAAm/(AloKr/L-Arg) core-shell fibers was (93.33 ± 35.11 nm) with finer and straighter fibers and higher water holding capacity due to increased surface area to volume ratio. In terms of tensile properties, the PAAm/(AloKr/L-Arg) core-shell nanofibers with tensile strength and elastic modulus of 2.84 ± 0.27 MPa and 62.15 ± 5.32 MPa, respectively, showed the best mechanical performance compared to other nanofibers tested. Furthermore, PAAm/(AloKr/L-Arg) exhibited the highest L-Arg release (87.62 ± 3.02 %) and viability of L929 cells in vitro compared to other groups. In addition, the highest rate of in vivo full thickness wound healing was observed in PAAm/(AloKr/L-Arg) group compared to other groups. It significantly enhanced the angiogenesis, neovascularization, and cell proliferation. The prepared PAAm/(AloKr/L-Arg) core-shell nanofibrous dressing could be promising for full-thickness wound healing.

Nanostructured magnetic Mg2SiO4-CoFe2O4 composite scaffold with multiple capabilities for bone tissue regeneration.

Multifunctional magnetic 3D scaffolds are recently of particular interest because of their applications in hyperthermia-based therapy and localized drug delivery beside of their basic properties to be applied in bone tissue regeneration. In the current study, a magnetic nanocomposite is designed and synthesized through a two-step synthesis strategy in which CoFe2O4 nanoparticles are prepared via sol-gel combustion method and then they are coated through sol-gel method with Mg2SiO4. The characterization relates to the nanocomposite shows that Mg2SiO4-CoFe2O4 is successfully synthesized and it has a core-shell structure. Then, 3D scaffolds are fabricated through polymer sponge technique from the nanocomposite. Physiochemical and biological properties of the scaffolds are assessed in vitro amongst which bioactivity, biodegradability, mechanical properties, hyperthermia capability, controlled release potential, antibacterial activity, cell compatibility and attachment can be mentioned. The results demonstrate that the scaffolds have high porous structure with interconnected porosity and desirable mechanical properties close to cancellous bone. The magnetic scaffold is biodegradable and bioactive and exhibits controlled release of rifampin as an antibiotic drug up to 96 h. Moreover, in the exposure of different magnetic fields it has potential to produce heat for different kinds of hyperthermia-based therapies. The antibacterial activity of drug-loaded scaffold is assessed against S. aureus bacteria. The results suggest that Mg2SiO4-CoFe2O4 nanocomposite scaffold with multiple capabilities has a great potential to be applied in the case of large bone defects which are caused by tumors to not only eradicate remained cancerous tissues, but also prevent infection after surgery and regenerate bone defect.