Piezoelectricity, Pyroelectricity, and Ferroelectricity in Biomaterials and Biomedical Applications.

Piezoelectric, pyroelectric, and ferroelectric materials are considered unique biomedical materials due to their dielectric crystals and asymmetric centers that allow them to directly convert various primary forms of energy in the environment, such as sunlight, mechanical energy, and thermal energy, into secondary energy, such as electricity and chemical energy. These materials possess exceptional energy conversion ability and excellent catalytic properties, which have led to their widespread usage within biomedical fields. Numerous biomedical applications have demonstrated great potential with these materials, including disease treatment, biosensors, and tissue engineering. For example, piezoelectric materials are used to stimulate cell growth in bone regeneration, while pyroelectric materials are applied in skin cancer detection and imaging. Ferroelectric materials have even found use in neural implants that record and stimulate electrical activity in the brain. This paper reviews the relationship between ferroelectric, piezoelectric, and pyroelectric effects and the fundamental principles of different catalytic reactions. It also highlights the preparation methods of these three materials and the significant progress made in their biomedical applications. The review concludes by presenting key challenges and future prospects for efficient catalysts based on piezoelectric, pyroelectric, and ferroelectric nanomaterials for biomedical applications.

Pyrolysis temperature matters: Biochar-derived dissolved organic matter modulates aging behavior and biotoxicity of microplastics.

Microplastics (MPs) have emerged as a novel and highly concerning contaminant that is ubiquitous in the aqueous environment. However, the aging of MPs induced by dissolved organic matter (DOM), especially biochar-derived dissolved organic matter (BDOM), and the biological toxicity after aging are not fully understood. In this study, the effects of biochar-derived BDOMs on the photoaging and biotoxicity of MPs were investigated at different pyrolysis temperatures using micro-scale polyethylene (PE) as an example. The results showed that the amount of ·OH generated by the BDOM/PE systems was related to the molecular composition and structure of BDOMs. High temperature BDOM7/9 with less lignin-like (34.33 % / 41.80 %) and more lipid (24.58 % / 19.88 %) content could produce more ·OH by itself, and its binding ability with PE was weaker due to its less hydrophobic components (SUVA260 = 0.10 / 0.11), which resulted in a weaker shading effect and less inhibition of the system, thus resulting in more ·OH production in the high temperature BDOM7/9/PE system. However, the involvement of BDOM, although favoring the long-term stable ·OH production of the system, did not significantly promote the photoaging of MPs. Furthermore, combined in vivo and in vitro biotoxicity studies of MPs showed that photoaging PE with the involvement of BDOM greatly improved systemic inflammation and tissue damage, as well as reactive oxygen species (ROS, such as ·OH and -OH)-induced cell death. For example, the addition of BDOM5/PE-light reduced the cell death of human lung, liver, and kidney cells from 54.70 %, 69.39 %, and 48.35 % to 22.78 %, 33.13 %, and 25.83 %, respectively, compared to the PE-light group. The results of this study contribute to an in-depth understanding of the environmental behavior of BDOM and MPs systems.