Synthesis of an aqueous, air-stable, superconducting 1T'-WS2 monolayer ink.

Liquid-phase chemical exfoliation can achieve industry-scale production of two-dimensional (2D) materials for a wide range of applications. However, many 2D materials with potential applications in quantum technologies often fail to leave the laboratory setting because of their air sensitivity and depreciation of physical performance after chemical processing. We report a simple chemical exfoliation method to create a stable, aqueous, surfactant-free, superconducting ink containing phase-pure 1T'-WS2 monolayers that are isostructural to the air-sensitive topological insulator 1T'-WTe2. The printed film is metallic at room temperature and superconducting below 7.3 kelvin, shows strong anisotropic unconventional superconducting behavior with an in-plane and out-of-plane upper critical magnetic field of 30.1 and 5.3 tesla, and is stable at ambient conditions for at least 30 days. Our results show that chemical processing can make nontrivial 2D materials that were formerly only studied in laboratories commercially accessible.

Mineralized Hydrogels Induce Bone Regeneration in Critical Size Cranial Defects.

Sequential mineralization enables the integration of minerals within the 3D structure of hydrogels. Hydrolyzed collagen-based hydrogels are sequentially mineralized over 10 cycles. One cycle is defined as an incubation period in calcium chloride dihydrate followed by incubation in sodium phosphate dibasic dihydrate. Separate cycles are completed at 30-minute and 24-hour intervals. For the gels mineralized for 30 min and 24 h, the compressive moduli increases from 4.25 to 87.57 kPa and from 4.25 to 125.47 kPa, respectively, as the cycle number increases from 0 to 10. As indicated by X-ray diffraction (XRD) and Fourier transform infrared analysis (FTIR) analyses, the minerals in the scaffolds are mainly hydroxyapatite. In vitro experiments, which measure mechanical properties, porous structure, mineral content, and gene expression are performed to evaluate the physical properties and osteoinductivity of the scaffolds. Real time-quantitative polymerase chain reaction (RT-qPCR) demonstrates 4-10 fold increase in the expression of BMP-7 and osteocalcin. The in vivo subcutaneous implantation demonstrates that the scaffolds are biocompatible and 90% biodegradable. The critical size cranial defects in vivo exhibit nearly complete bone regeneration. Cycle 10 hydrogels mineralized for 24 h have a volume of 59.86 mm3 and a density of 1946.45 HU. These results demonstrate the suitability of sequentially mineralized hydrogel scaffolds for bone repair and regeneration.

Mineralization of Biomaterials for Bone Tissue Engineering.

Mineralized biomaterials have been demonstrated to enhance bone regeneration compared to their non-mineralized analogs. As non-mineralized scaffolds do not perform as well as mineralized scaffolds in terms of their mechanical and surface properties, osteoconductivity and osteoinductivity, mineralization strategies are promising methods in the development of functional biomimetic bone scaffolds. In particular, the mineralization of three-dimensional (3D) scaffolds has become a promising approach for guided bone regeneration. In this paper, we review the major approaches used for mineralizing tissue engineering constructs. The resulting scaffolds provide minerals chemically similar to the inorganic component of natural bone, carbonated apatite, Ca5(PO4,CO3)3(OH). In addition, we discuss the characterization techniques that are used to characterize the mineralized scaffolds, such as the degree of mineralization, surface characteristics, mechanical properties of the scaffolds, and the chemical composition of the deposited minerals. In vitro cell culture studies show that the mineralized scaffolds are highly osteoinductive. We also summarize, based on literature examples, the applications of 3D mineralized constructs, as well as the rationale behind their use. The mineralized scaffolds have improved bone regeneration in animal models due to the enhanced mechanical properties and cell recruitment capability making them a preferable option for bone tissue engineering over non-mineralized scaffolds.