Seriously interesting...

Seriously interesting material.

https://inflammregen.biomedcentral.com/articles/10.1186/s41232-018-0059-8

Boron nitrideBoron nitride nanotube has superior piezoelectric property than that of piezoelectric polymers [108]. Researchers are exploited BNNTs as nano vectors to carry electrical /mechanical stimuli on demand within a cellular system. After BNNT internalization, the electrical stimulation has conveyed to tissue or/ cell culture using a wireless mechanical source (i.e., ultrasound) (Fig. 3). Its cytocompatibility can be improved by improving its dispersibility in the solvents. It is reported that its dispersibility can be improved by non-covalent polymeric wrapping or by using non-toxic surfactants, which has been increased its potential for biomedical application [109]. The proper functionalization of BNNT with glycol-chitosan or the addition of surfactant poly-L-lysine (PLL) or polyethyleneimine (PEI) results in the formation of BNNT dispersion and improves the cytocompatibility of BNNT [110]. The studies have been demonstrated that biodegradable polymeric scaffold reinforced with BNNT has a positive influence on osteoblast proliferation and differentiation [111, 112]. The studies report that the BNNT has a negative influence on the chondrocytes, fibroblast and smooth muscle cells. It decreases the adhesion of chondrocytes, fibroblasts and smooth muscle cells while it can increase the adhesion of osteoblast cells [110]. Moreover, it has excellent mechanical properties and highly crucial for orthopedic applications [113]. Hence BNNT is an excellent material for bone tissue engineering.



Future prospectivePiezoelectric collagen fibers are present in cartilage and bone, but the function of piezoelectricity is not yet fully investigated. The piezoelectric material can act as a mechanoelectrical transducer. The electroactive scaffolds can generate the electric field in response to minute mechanical vibrations. Also the scaffold of piezoelectric material can be tuned the effective electric field characteristics of the natural ECM observed during development, regeneration or repair of the tissues. The scaffold can directly influence the osteoblast or chondroblast cells and can promote its adhesion and proliferation, further the production of ECM and thereby repair of damaged sites. Moreover it can stimulate the mesenchymal stem cells directly and further its differentiation into chondroblasts or osteoblasts. Therefore, the smart piezoelectric biomaterials require strong attention towards tissue engineering, particularly bone, cartilage and nerve regeneration. These materials will offer natural physiological conditions like ECM to regulate the signaling pathways to stimulate the regeneration mechanism. Significantly, the piezoelectric scaffolds can enhance the cell functionality without the addition of growth factors and drug molecules. The stimulating factors implanted treatments are highly expensive, highly instable (extra and random growth of tissue), complicated selection criteria (lack of dose optimization criteria) and dose related complications. Even more, the stimulating factors implanted scaffolds, further compacted the treatment procedure. Therefore, the smart piezoelectric material based scaffolds can be better alternative to aforementioned conventional therapies. The smart scaffold utilizes the functional loads as stimulating factor to regenerate the tissue by effect. The tissue regeneration can be regulated by natural feedback system to maintain the integration of the system. Hence, the class of piezoelectric materials has huge research and market scope for advanced tissue engineering therapies.ConclusionThe present review provides the brief insight about the importance of the alternative technologies like smart materials in regenerative medicine. The detailed information about various piezoelectric materials for bone and cartilage tissue engineering has been presented in the report. Numerous piezoelectric materials are available and proved its effectiveness in the field of sensors; actuators etc. while the exploration of their biomedical applications are exponentially increased in last decade. Piezoelectric polymers/ biopolymers like, PHBV, PLLA, PVDF, collagen and cellulose etc. have been discussed in detail in terms of applications and their physical properties. Piezoceramics have been debated for their applications for hard tissue regeneration with various forms. Hence, the piezoelectric smart materials are best possible futuristic materials for regenerative medicine.