Preparation and characterisation of a novel silk fibroin/hyaluronic acid/sodium alginate scaffold for skin repair.

To mimic the natural structure of tissue extracellular matrix, a novel silk fibroin (SF)/hyaluronic acid (HA)/sodium alginate (SA) composite scaffold (92% in porosity) was prepared by freeze-drying. Fourier-transform infrared spectroscopy and Raman spectra indicated interactions among SF, HA, and SA molecules. Scanning electron microscopy showed that the prepared SF/HA/SA scaffold had soft, elastic characteristics, with an average pore diameter of 93 µm. Mechanical property, thermogravimetric analyses and degradation results indicated that the SF/HA/SA scaffold had good physical stability in body fluid and mechanical movement-related environments. Cell proliferation, morphological, and live-dead analyses showed that NIH-3T3 fibroblast cells were better able to attach, grow, and proliferate on the SF/HA/SA scaffold compared with SF, SF/HA, and SF/SA scaffolds. We evaluated the wound healing effects in a rat full-thickness burn model. The hematoxylin-eosin (H&E) and Masson's trichrome staining results from SF/HA/SA scaffold showed that improved re-epithelialization, enhanced extracellular matrix remodeling. Our findings showed that the prepared SF/HA/SA scaffold can provide a potential way as a wound dressing for skin repair.

Preparation and characterization of the collagen/cellulose nanocrystals/USPIO scaffolds loaded kartogenin for cartilage regeneration.

The regeneration of cartilage is a challenging problem for lack of innate abilities to mount a sufficient healing response. Kartogenin (KGN), an emerging chondroinductive non-protein small molecule, bound to the surface of the ultrasmall super-paramagnetic iron-oxide (USPIO) by innovational one-step technology, followed by being incorporated into the cross-linking collagen/cellulose nanocrystals (Col/CNC) bioactive scaffolds to stimulate an appropriate microenvironment for the growth and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs), thus facilitating the formation of chondrocyte. Herein, USPIO not only served as a carrier for small molecule drugs, but also as MRI contrast agents, which can non-invasively monitor the degradation of the scaffolds and the self-repair capacity of cartilage. In vitro studies showed that the KGN could release from the composite scaffolds in a sustained and stable manner and promote the chondrogenic differentiation of BMSCs based on UV spectrophotometry test, and specific markers analysis. Of note, USPIO labeled composite scaffolds retained their stability without loss of relaxation rate the composite scaffolds can be a promising biomaterials for cartilage repair, with the function of noninvasive visualization and semiquantitative analysis of scaffolds degradation and neocartilage.

Preparation and characterization of 3D porous conductive scaffolds with magnetic resonance enhancement in tissue engineering.

Magnetic resonance imaging (MRI), as a diagnostic tool in tissue engineering, has received widespread attention because of its ability to consistently provide degradation and absorption of implants in vivo. For some specific human tissues and organs, such as nerves, muscles and myocardium, their regeneration requires tissue engineering scaffolds have a good electrical conductivity. Graphene oxide (GO) has been extensively studied as a conductive biomaterial having mechanical reinforcement. Based on the above, we propose an MRI conductive scaffold containing gelatin (Gel)/gelatin-polycaprolactone (Gel-PCL)/ultra-small paramagnetic iron oxide (USPIO)/graphene oxide (GO) (Gel/Gel-PCL/USPIO/GO). Their physical and chemical properties as well as biocompatibility are measured in vitro. The purpose of doping USPIO was developed for non-invasive monitoring of tissue engineered implants and tissue reconstruction. Functional modification of GO to match electrophysiological requirement. Co-culture with bone marrow mesenchymal stem cells showed good biocompatibility. Blood experiments have also demonstrated the feasibility of scaffolds as tissue engineered implants. The USPIO-labeled conductive scaffold, as an effective image-guided and electrically stimulating implant, appears to be a reconstruction platform for specific tissues and organs.