Nanomaterial-integrated injectable hydrogels for craniofacial bone reconstruction.

The complex anatomy and biology of craniofacial bones pose difficulties in their effective and precise reconstruction. Injectable hydrogels (IHs) with water-swollen networks are emerging as a shape-adaptive alternative for noninvasively rebuilding craniofacial bones. The advent of versatile nanomaterials (NMs) customizes IHs with strengthened mechanical properties and therapeutically favorable performance, presenting excellent contenders over traditional substitutes. Structurally, NM-reinforced IHs are energy dissipative and covalently crosslinked, providing the mechanics necessary to support craniofacial structures and physiological functions. Biofunctionally, incorporating unique NMs into IH expands a plethora of biological activities, including immunomodulatory, osteogenic, angiogenic, and antibacterial effects, further favoring controllable dynamic tissue regeneration. Mechanistically, NM-engineered IHs optimize the physical traits to direct cell responses, regulate intracellular signaling pathways, and control the release of biomolecules, collectively bestowing structure-induced features and multifunctionality. By encompassing state-of-the-art advances in NM-integrated IHs, this review offers a foundation for future clinical translation of craniofacial bone reconstruction.

Bio-inspired nanocomposite coatings on orthodontic archwires with corrosion resistant and antibacterial properties.

The corrosion resistance and antibacterial properties of fixed orthodontic devices are insufficient in the complex oral cavity, which delays tooth movement and causes enamel demineralization. To overcome the challenges, this research constructs a series of polydopamine-graphene oxide (PDA-GO) nanocoatings on representative NiTi archwires via self-assembly. The morphology, chemical structure, and multifunctional properties of coatings showed tunability dependent on the PDA/GO ratio. Optimized PDA-GO coatings with uniform and dense characteristics prolonged the diffusion path for the corrosive medium and reduced Ni dissolution in NiTi alloys. Meanwhile, the applied coatings endowed NiTi alloys with antibacterial activity against Streptococcus mutans due to the surface structures and inherent properties of PDA-GO. In vitro cytotoxicity tests further verified their good biocompatibility. This bio-inspired nanocomposite coating provides a practical reference for modification of dental metal surfaces to better behave in the intraoral environment.

Enhancing proliferation and osteogenic differentiation of HMSCs on casein/chitosan multilayer films.

Creating a bioactive surface is important in tissue engineering. Inspired by the natural calcium binding property of casein (CA), multilayer films ((CA/CS)n) with chitosan (CS) as polycation were fabricated to enhance biomineralization, cell adhesion and differentiation. LBL self-assembly technique was used and the assembly process was intensively studied based on changes of UV absorbance, zeta potential and water contact angle. The increasing content of chitosan and casein with bilayers was further confirmed with XPS and TOF-SIMS analysis. To improve the biocompatibility, gelatin was surface grafted. In vitro mineralization test demonstrated that multilayer films had more hydroxyapatite crystal deposition. Human mesenchymal stem cells (HMSCs) were seeded onto these films. According to fluorescein diacetate (FDA) and cell cytoskeleton staining, MTT assay, expression of osteogenic marker genes, ALP activity, and calcium deposition quantification, it was found that these multilayer films significantly promoted HMSCs attachment, proliferation and osteogenic differentiation than TCPS control.

Estimating glomerular filtration rates in elderly Chinese patients with chronic kidney disease: performance of six modified formulae developed in Asian populations.

OBJECTIVES: The aim of the present study was to evaluate modified glomerular filtration rate (GFR) prediction formulae in an elderly Chinese population with chronic kidney disease (CKD). METHODS: A total of 378 elderly Chinese patients with CKD were enrolled. The GFR was estimated with six modified GFR prediction formulae. The performances of the estimated GFRs were compared with those of the standard GFRs measured by technetium-99m diethyl-enetraminepentaacetic acid. RESULTS: Biases were similar for Chinese formula 1, the Asian formula, and Chinese formula 2 (median difference, 2.22 mL/min/1.73 m(2) and 2.59 mL/min/1.73 m(2) for Chinese formula 1 and the Asian formula, respectively, versus (vs) 3.69 mL/min/1.73 m(2) for Chinese formula 2 [P = 0.298 and P = 0.913, respectively]). Precision was improved with the Japanese formula (interquartile range of the difference, 3.14 mL/min/1.73 m(2) of the Japanese formula versus 15.53-23.06 mL/min/1.73 m(2) of the other formulae). The accuracy of Chinese formula 2 was the highest (30% accuracy, 59.3% vs range 37.8-54.0% [P < 0.05 for all comparisons]). However, none of the modified formulae surpassed the acceptable tolerance (>70%), and the GFR category misclassification rates for all the formulae exceeded 50%. CONCLUSION: Our findings suggest that all six modified formulae developed in Asian populations may show great bias in elderly Chinese patients with CKD. Also, our study suggests the need for uniform measures for the assessment of CKD in the elderly to guarantee better sensitivity and specificity.

Phosphatidylserine enhances osteogenic differentiation in human mesenchymal stem cells via ERK signal pathways.

Phosphatidylserine (PS) has been demonstrated to promote bone mineralization. It has also been used in bone repairing biomaterials as a functional molecule. However, the effect of PS on mesenchymal stem cells (MSCs) is not clear. In this study, we determined the effect of PS on the osteogenic differentiation of human MSCs (hMSCs) cultured in growth or osteogenic differentiation medium and the role of the ERK1/2 signaling pathway on PS activity. Cytotoxicity of PS was measured by MTT assay in growth medium for 5 days. Cell osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity analysis, Alizarin Red S staining and real-time PCR assay. Western blotting and ERK blocking assay were used to examine the role of ERK1/2 signaling pathway on PS activity. The results showed no cytotoxicity for the doses of PS administered. For 21 days, 50-100 µM PS increased ALP expression and mineralization of hMSCs. The expression of the osteogenic gene marker, ALP, osteocalcin (OC), and RUNX2 was enhanced by 50 µM PS treatment at day 14. Phospho-ERK was activated by 50 µM PS at 30 min and 1h in growth medium. In osteogenic medium, 50 µM PS extended phospho-ERK activation by osteogenic induction medium from 30 min to 8 h. U0126, an ERK inhibitor, suppressed the ALP expression induced by PS. Our data indicate that the ERK signal is potentially a mediator in the process of osteogenic differentiation of hMSCs induced by PS. PS, as a functional molecule, has high potential for use in bone repairing biomaterials and bone tissue engineering.