Recently, electrical stimulation as a physical stimulus draws lots of attention. It shows great potential in disease treatment, wound healing, and mechanism study because of significant experimental performance. Electrical stimulation can activate many intracellular signaling pathways, and influence intracellular microenvironment, as a result, affect cell migration, cell proliferation, and cell differentiation. Electrical stimulation is using in tissue engineering as a novel type of tool in regeneration medicine. Besides, with the advantages of biocompatible conductive materials coming into view, the combination of electrical stimulation with suitable tissue engineered scaffolds can well combine the benefits of both and is ideal for the field of regenerative medicine. In this review, we summarize the various materials and latest technologies to deliver electrical stimulation. The influences of electrical stimulation on cell alignment, migration and its underlying mechanisms are discussed. Then the effect of electrical stimulation on cell proliferation and differentiation are also discussed.

No abstract

A biocompatible hydrogel of hyaluronic acid with the neurite-promoting peptide sequence of IKVAV was synthesized. The characterization of the hydrogel shows an open porous structure and a large surface area available for cell interaction. Its ability to promote tissue repair and axonal regeneration in the lesioned rat cerebrum is also evaluated. After implantation, the polymer hydrogel repaired the tissue defect and formed a permissive interface with the host tissue. Axonal growth occurred within the microstructure of the network. Within 6 weeks the polymer implant was invaded by host-derived tissue, glial cells, blood vessels and axons. Such a hydrogel matrix showed the properties of neuron conduction. It has the potential to repair tissue defects in the central nervous system by promoting the formation of a tissue matrix and axonal growth by replacing the lost tissue.

The mechanical properties of hydroxyapatite (HAp) bioceramic material were improved significantly by adding tetragonal-zirconia-polycrystalline (TZP) powder coated with Al 2 O 3 . The coating was done by dispersing the TZP powder in a boehmite suspension and adjusting the pH to cause heterocoagulation. The coating effectively reduced the deleterious reaction between the HAp and the TZP that tended to form tricalcium phosphate (TCP) and fully stabilized cubic zirconia. When 15 vol% zirconia and 30 vol% alumina were added to the HAp by the coating method, the strength and the fracture toughness of the composite were 300 MPa and 3 MPa⅐m 1/2 , respectively, which are about 3 times higher than those of pure HAp.

Microtomographic techniques are widely used for studying the trabecular architectures in the orthopedics and elucidation of tooth micromorphology in the field of dentistry. Its application to assess the osseointegration of dental implants has been studied as a non-invasive method, contrary to several conventional methods. The aim of this study is to evaluate the possibility of microtomography as a tool for assessing osseointegration. Twenty-four titanium dental implants (3.75 mm in diameter and 7 mm in total length) were installed in the tibia of New Zealand white rabbits, and retrieved with the surrounding bone after 3 months. The specimens were analyzed by three-dimensional microtomogram images (Skyscan 1074) and compared with the conventional histomorphography. The correlation coefficient was found to be 0.855, which means the two data sources are significantly correlated statistically. To predict the histomorphometric data using microtomographic data, a linear regression model was applied. These results showed some promise of using microtomograms for non-invasive osseointegration assessment if the methods can be calibrated more precisely by further study.