No abstract

Diabetes has made it challenging to repair alveolar bone defects. A successful method for bone repair utilizes a glucose-sensitive osteogenic drug delivery. This study created a new glucose-sensitive nanofiber scaffold with controlled dexamethasone (DEX) release. DEX-loaded polycaprolactone/chitosan (PCL/CS) nanofibers scaffolds were created using electrospinning. The nanofibers had high porosity (>90%) and proper drug loading efficiency (85.51 ± 1.21%). Then, glucose oxidase (GOD) was immobilized on the obtained scaffolds by a natural biological cross-linking agent, genipin (GnP), after soaking in the mixture solution containing GOD and GnP. The enzyme properties and glucose sensitivity of the nanofibers were investigated. The results showed that GOD was immobilized on the nanofibers and exhibited good enzyme activity and stability. Meanwhile, the nanofibers expanded gradually in response to the increase in glucose concentration, followed by the release of DEX increased. The phenomena indicated that the nanofibers could sense glucose fluctuation and possess favorable glucose sensitivity. In addition, the genipin nanofibers group showed lower cytotoxicity in the biocompatibility test compared with a traditional chemical cross-linking agent. Lastly, the associated osteogenesis evaluation found that the scaffolds effectively promoted MC3T3-E1 cells' osteogenic differentiation in high-glucose environments. As a result, the glucose-sensitive nanofibers scaffolds offer a viable treatment option for people with diabetes with alveolar bone defects.

Three-dimensional (3D) printing of hydrogels to form complex structures has been widely used in tissue engineering. Projection-based 3D printing (PBP) has faster printing, lower cell damage, and higher printing resolution compared with other 3D printing methods, providing a potential strategy for printing elaborate 3D hydrogel structures. In this review, we introduced the composition and printing process of PBP. We then discuss the study of hydrogels for PBP, including chemical structure modification and property optimization.More importantly, we highlight the potential applications of PBP-based hydrogels in regenerative medicine and tissue engineering, and discuss the current challenges and future prospects of PBP-based hydrogels. Ideas are provided for the study of PBP, hydrogel bioinks, and related fields.

In the complicated process of bone regeneration, osteogenic differentiation and angiogenesis are crucial. In this study, a novel dual small molecule composite electrospun scaffold was prepared using polycaprolactone embedded with angiogenic factor tauro-ursodeoxycholic acid and osteogenic factor dexamethasone to promote early angiogenesis and osteogenesis. Additionally, the related properties, angiogenic activity, and osteogenic activity analyses were conducted for the scaffold. The results demonstrated that the composite scaffold possessed proper mechanical properties and hydrophilicity. During the initial drug release, the release rate of the hydrophilic drug tauroursodeoxycholic acid was higher compared to the hydrophobic drug dexamethasonethe. The drugs were slowly sustained released for more than 528 h.The composite scaffold boosted cell proliferation and accelerated osteogenic differentiation up to 21 days. The alkaline phosphatase activity and mineral deposition were comparatively higher on dual drug-releasing fibers compared to control scaffolds. Wound healing migration assay and tube formation assay for further in vitro revealed that the composite scaffold exhibited higher efficiency in promoting cell migration and the angiogenesis ductive. Hence, the composite scaffold had a high potential for promoting bone regeneration by enhancing angiogenesis.

The effective treatment of Ga-containing wastewater from the Bayer process is a promising strategy for the sustainable development of the gallium resource. Among the adsorption materials, nanofibers play indispensable roles in the recovery of gallium with their adsorption capacity. However, developing facile, easy scale-up, and low-cost grafting methods for polyacrylonitrile nanofiber membranes (PAN NFs) is still challenging in view of the traditional grafting methods with lower grafting rates and strict requirement of fiber flexibility. In this study, a newly and highly efficient amidoxime nanofiber membrane preparation method with electrostatic spinning technology was explored to apply in the Ga­(III) adsorption from Ga-containing wastewater. The results of Ga­(III) adsorption studies by amidoxime polyacrylonitrile nanofiber membranes (AOPAN NFs) showed that Ga­(III) was remarkably consistent with the Langmuir isotherm, with a maximum adsorption capacity of 39.80 mg/g of Ga­(III) at 30 °C, a gallium concentration of 200 mg/L, a solid to liquid ratio of 1.0 mg/mL, and a solution pH of 12, which is generally higher than those of other materials. The kinetic adsorption experiment demonstrated that the adsorption process was controlled by a chemical reaction and followed the pseudo-second-order kinetic model. Furthermore, the adsorption mechanism of AOPAN NFs was proposed, and the oxime group played an essential role in the adsorption process. This strategy combines the advantages of AOPAN NFs to open up a new way to develop the next generation of gallium adsorption materials.