Promotion of neuronal regeneration by using self-polymerized dendritic polypeptide scaffold for spinal cord tissue engineering.

Tissue engineering technology is applicable for study of nerve regeneration after spinal cord injury. Many natural and artificial scaffold are not applicable because of poor mechanical properties and cell compatibility. Polypeptides with fine three-dimensional structure and cell compatibility and are widely used in tissue engineering research. The purpose of this study was to verify the neuronal differentiation of neural stem cells by using self-polymerize dendritic polypeptide for spinal cord tissue engineering. Neural stem cells were isolated from cerebral cortex of neonatal SD rats.Conventional media was triggered the 1wt% nano peptide solution self polymerizated to formed a nano gel. The gel was tested by scanning electron microscope and transmission electron microscope. Neural stem cells were inoculated onto gel or on Polylysine-coated slides with fetal bovine serum or not. SD rats were randomized divided into four groups. neural stem cells and self-polymerized peptide were transplanted into spinal cord injury models. Then we test the Density of NF-positive axons in the spinal cord injury area at 8 weeks after surgery and MS score of the locomotive function of hind limbs among mice of four groups. Neural stem cells were showed anti Nestin (+), anti NSE (+), anti GFAP (+). The gel tested by scanning electron microscope was showed thick wall structure, another one tested by transmission electron microscope was showed self-polymerized dendritic nanofibers, which contains several spacings. The cells in serum group were differentiate into neurons, but non serum group were not. These results suggest that the self-assembling peptide nanofiber scaffold(SAPNS) were cytocompatible to neural stem cells which were differentiated into neurons. A large number of axonal regeneration and recovery of joint function of hind limb were appeared. The self-polymerized Peptide maybe used as practical tissue engineering materials as future.

Fibrous scaffolds made by co-electrospinning soluble eggshell membrane protein with biodegradable synthetic polymers.

Soluble eggshell membrane protein (SEP), isolated from natural eggshell membrane, was co-electrospun with biodegradable synthetic polymers poly(propylene carbonate) (PPC) and poly(lactic acid) (PLA) in various proportions from 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solutions in order to prepare fibrous scaffolds having simultaneously good mechanical properties and biocompatibility. The fiber morphology was observed by field emission scanning electron microscopy, showing uniform fibers with diameter of 1.2-1.0 and 1.3-0.7 um for PPC/SEP and PLA/SEP blend fibers, respectively. Transmission electron microscopy observation shows that the blend fibers have domain-matrix phase morphology with fiber-like SEP domains in the PPC or PLA matrix, indicating the occurrence of phase separation, although interaction exists between PPC (or PLA) and SEP, as revealed by attenuated total reflectance Fourier transform infrared spectroscopy. The mechanical properties were evaluated by uniaxial tensile tests and showed that both the tensile strength and elongation at break increase with increasing incorporation of PPC (or PLA). The surface composition was investigated by X-ray photoelectron spectroscopy and SEP was found on the fiber surfaces, and as a result the surfaces of the fibrous scaffolds are superhydrophilic. NIH3T3 cell culture tests demonstrate that the PPC/SEP and PLA/SEP blend fibrous scaffolds have a much improved biocompatibility compared to pure PPC or PLA fibrous scaffolds.

Surface engineering of poly(D,L-lactic acid) by entrapment of soluble eggshell membrane protein.

Soluble eggshell membrane protein (SEP) is used to engineer poly(D,L-lactic acid) (PDL-LA) membrane surface by a physical entrapment method to enhance cytocompatibility. Attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle measurements are used to characterize SEP-modified PDL-LA membrane surface and confirm the formation of an even and stable layer of SEP on PDL-LA membrane surface. NIH3T3 cell lines are used as model cells to evaluate cytocompatibility of the SEP-modified PDL-LA membrane, which is much better than that of virgin PDL-LA membrane. The enhanced cytocompatibility facilitates potential application in tissue engineering.

Mechanical properties and biocompatibility of soluble eggshell membrane protein/poly(vinyl alcohol) blend films.

Poly(vinyl alcohol) (PVA) has been blended with soluble eggshell membrane protein (SEP) to improve the mechanical properties of SEP film that is brittle. Tensile strength and elongation-at-break increase with increasing amount of PVA. When the SEP/PVA proportion is 1:1, a strong and flexible film is obtained, having a tensile strength of 22.7 MPa and elongation-at-break of 106%. Although scanning electron microscopy observation of the freeze-fractured cross-section shows microphase separation, interaction between SEP and PVA exists, as revealed by FT-IR. NIH3T3 cell culture demonstrates that SEP/PVA blend films with up to 50% of PVA show biocompatibility comparable to pure SEP film.