Piezocatalytically-induced controllable mineralization scaffold with bone-like microenvironment to achieve endogenous bone regeneration.

Orderly hierarchical structure with balanced mechanical, chemical, and electrical properties is the basis of the natural bone microenvironment. Inspired by nature, we developed a piezocatalytically-induced controlled mineralization strategy using piezoelectric polymer poly-L-lactic acid (PLLA) fibers with ordered micro-nano structures to prepare biomimetic tissue engineering scaffolds with a bone-like microenvironment (pcm-PLLA), in which PLLA-mediated piezoelectric catalysis promoted the in-situ polymerization of dopamine and subsequently regulated the controllable growth of hydroxyapatite crystals on the fiber surface. PLLA fibers, as analogs of mineralized collagen fibers, were arranged in an oriented manner, and ultimately formed a bone-like interconnected pore structure; in addition, they also provided bone-like piezoelectric properties. The uniformly sized HA nanocrystals formed by controlled mineralization provided a bone-like mechanical strength and chemical environment. The pcm-PLLA scaffold could rapidly recruit endogenous stem cells, and promote their osteogenic differentiation by activating cell membrane calcium channels and PI3K signaling pathways through ultrasound-responsive piezoelectric signals. In addition, the scaffold also provided a suitable microenvironment to promote macrophage M2 polarization and angiogenesis, thereby enhancing bone regeneration in skull defects of rats. The proposed piezocatalytically-induced controllable mineralization strategy provides a new idea for the development of tissue engineering scaffolds that can be implemented for multimodal physical stimulation therapy.

Application of Piezoelectric Material and Devices in Bone Regeneration.

Bone injuries are common in clinical practice. Given the clear disadvantages of autologous bone grafting, more efficient and safer bone grafts need to be developed. Bone is a multidirectional and anisotropic piezoelectric material that exhibits an electrical microenvironment; therefore, electrical signals play a very important role in the process of bone repair, which can effectively promote osteoblast differentiation, migration, and bone regeneration. Piezoelectric materials can generate electricity under mechanical stress without requiring an external power supply; therefore, using it as a bone implant capable of harnessing the body's kinetic energy to generate the electrical signals needed for bone growth is very promising for bone regeneration. At the same time, devices composed of piezoelectric material using electromechanical conversion technology can effectively monitor the structural health of bone, which facilitates the adjustment of the treatment plan at any time. In this paper, the mechanism and classification of piezoelectric materials and their applications in the cell, tissue, sensing, and repair indicator monitoring aspects in the process of bone regeneration are systematically reviewed.

Cane Molasses Graphene Quantum Dots Passivated by PEG Functionalization for Detection of Metal Ions.

Poly(ethylene glycol) passivated graphene quantum dots (PEG-GQDs) were synthesized based on a green and effective strategy of the hydrothermal treatment of cane molasses. The prepared PEG-GQDs, with an average size of 2.5 nm, exhibit a brighter blue fluorescence and a higher quantum yield (QY) (up to approximately 21.32%) than the QY of GQDs without surface passivation (QY = 10.44%). The PEG-GQDs can be used to detect and quantify paramagnetic transition-metal ions including Fe3+, Cu2+, Co2+, Ni2+, Pb2+, and Mn2+. In the case of ethylenediaminetetraacetic acid (EDTA) solution as a masking agent, Fe3+ ions can be well selectively determined in a transition-metal ion mixture, following the lowest limit of detection (LOD) of 5.77 µM. The quenching mechanism of Fe3+ on PEG-GQDs belongs to dynamic quenching. Furthermore, Fe3+ in human serum can be successfully detected by the PEG-GQDs, indicating that the green prepared PEG-GQDs can be applied as a promising candidate for the selective detection of Fe3+ in clinics.

Risk factors and management of gestational diabetes.

Gestational diabetes mellitus (GDM) is considered to be a typical condition of glucose intolerance in which a woman previously undiagnosed with diabetes exhibits high levels of blood glucose during the third trimester of pregnancy. It can hence be defined as any degree of intolerance to glucose with its first recognition only during the pregnancy. Approximately 7 % of all cases of pregnancy are found to be variedly complicated with GDM and this result in more than 200,000 cases annually. In US only, GDM has been found to complicate about 7-14 % cases annually, and the trend seems to have increased by 35-100 % in the recent years. A history of GDM can be considered to be one of the sturdiest risk factors concerning the development of type 2 diabetes. Among women who have a history of GDM, the risk of developing classical type 2 diabetes usually ranges from 20 to 50 %. Evidences collected from various efficacy trials suggest that lifestyle interventions like weight management can modulate and prevent type 2 diabetes in at-risk individuals. The cornerstone of GDM management is glycemic control, and hence, it is attributed to be the main focus of attention for the therapy. In this review, we have tried to highlight the various risk factors associated with GDM along with the available therapeutic options in the treatment and management of the disease.

Blossoming of nanosheet structures via a disturbed self-assembly.

Nanofabrication has been critical in all kinds of nanotechnology, not only for achieving various nanostructures or nanosystems but also for the application of the nanotechnology. To achieve controllable but simple nanofabrication is one of the central aspirations for many research communities; here, for the first time, we report the growth of nanosheet structures simply by introducing internal disturbances (adding nanoparticles and surface tension) or external disturbances (deformations) to the self-assembly of copolymers induced by evaporation. Nanoparticles, curved surface, and deformations by such as writing or extension have been employed to demonstrate the sensitivity of the nanosheet structures to various disturbances. Finally, a physical model has been proposed to explain how the disturbances contribute to the formation of the nanosheet structures. These significant results indicate a scalable, writable, cost-effective and environmentally friendly nanotechnology that will stimulate new nanofabrication research.

Effects of a block copolymer as multifunctional fillers on ionic conductivity, mechanical properties, and dimensional stability of solid polymer electrolytes.

Solid polymer electrolytes with high ionic conductivities, good mechanical properties, dimensional stability, and easy processability were obtained from poly(ethylene oxide)-block-polyethylene (PEO-b-PE)-loaded poly(ethylene oxide) (PEO)/lithium perchlorate (LiClO(4)). In this article, we reported that the ionic conductivity and mechanical properties were remarkably increased due to the addition of the PEO-b-PE compared to that of PEO/LiClO(4) electrolyte. Scanning electron microscope (SEM), optical micrograph, and X-ray diffraction (XRD) results indicate that the addition of the copolymer, PEO-b-PE, decreased the defects of the PEO electrolyte films. Good dimensional stability was observed by dynamic rheological techniques up to 100 °C (higher than the melting point of PEO, 65 °C). A bicontinuous phase structure, that is crystalline PE domains within a matrix of PEO/salt, was proposed as the mechanism for such comprehensive enhancements in the ionic conductivity, mechanical properties, and dimensional stability obtained simultaneously in this study through a facile approach based on incorporation of a copolymer.