Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

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Biomedical Applications of Biodegradable Polymers

Biopolymer-based hydrogels as scaffolds for tissue engineering applications: a review

Oxygen vacancies in crystal have important impacts on the electronic properties of ZnO. With ZnO2 as precursors, we introduce a high concentration of oxygen vacancies into ZnO successfully. The obtained ZnO exhibits a yellow color, and the absorption edge shifts to longer wavelength. Raman and XPS spectra reveal that the concentration of oxygen vacancies in the ZnO decreased when the samples are annealed at higher temperature in air. It is consistent with the theory calculation. The increasing of oxygen vacancies results in a narrowing bandgap and increases the visible light absorption of the ZnO. The narrowing bandgap can be confirmed by the enhancement of the photocurrent response when the ZnO was irradiated with visible light. The ZnO with oxygen vacancies are found to be efficient for photodecomposition of 2,4-dichlorophenol under visible light irradiation.

Oxygen vacancy induced band-gap narrowing and enhanced visible light photocatalytic activity of ZnO.

Synthesis methods for nanosized hydroxyapatite with diverse structures.

Optical Waveguide Theory

Enhancement of mechanical strength and osteogenesis, and inhibition of osteoclastic activity for β-tricalcium phosphate bioceramics by incorporating calcium silicate and magnesium-strontium phosphate

In this letter, we demonstrate a lateral AlGaN/GaN Schottky barrier diode (SBD) on sapphire substrate with low turn-on voltage (Von) and high breakdown voltage (VBK). By using a double barrier anode (DBA) structure formed by the mixture of Platinum (Pt) and Tantalum (Ta), the Von of the SBD can be as low as 0.36 V with a leakage current of 2.5×10-6 A/mm. Supported by the high-quality carbon-doped GaN buffer on sapphire, the VBK can reach more than 10 kV with the anode-to-cathode spacing of 85 μm. Combining the VBK and the specific on-resistance (Ron,sp) of 25.1 mΩ·cm2, the power figure of merit (VBK2/Ron,sp) of the SBD can reach 4.0 GW/cm2, demonstrating a great potential for the application in ultra-high-voltage electronics.

A Lateral AlGaN/GaN Schottky Barrier Diode with 0.36 V Turn-on Voltage and 10 kV Breakdown Voltage by Using Double Barrier Anode Structure

Although yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) ceramics have been widely used as restorative materials due to their high mechanical strength, unique esthetic effect, and good biocompatibility, their general application to implant materials is still limited by their biological inertness and hydrothermal aging phenomenon. Existing studies have attempted to investigate how to enhance the bioactivity or hydrothermal aging resistance of Y-TZP. Still, more studies need to be done on the modification that combines these two aspects. In this study, Y-TZP was prepared by 77S bioactive glass (BG) sol and akermanite (AKT) sol infiltration and microwave sintering, which provided Y-TZP with high bioactivity while maintaining resistance to hydrothermal aging. Results of phase composition evaluation, microstructural characteristics, and mechanical property tests showed that modified Y-TZP specimens exhibited little or no tetragonal-to-monoclinic (t → m) transformation and maintained relatively high mechanical properties after accelerated hydrothermal aging treatment. The in vitro biological behaviors showed that the introduction of 77S BG and AKT significantly promoted cell adhesion, spreading, viability, and proliferation on the surface of modified Y-TZP ceramics. Therefore, this modification could effectively enhance the bioactivity and hydrothermal aging resistance of Y-TZP ceramics for its application in dental implant materials.

Jiandong Ye

Papers

Enhancement of mechanical strength and osteogenesis, and inhibition of osteoclastic activity for β-tricalcium phosphate bioceramics by incorporating calcium silicate and magnesium-strontium phosphate

A Lateral AlGaN/GaN Schottky Barrier Diode with 0.36 V Turn-on Voltage and 10 kV Breakdown Voltage by Using Double Barrier Anode Structure

Enhanced bioactivity and hydrothermal aging resistance of Y-TZP ceramics for dental implant.

Solitary fibrous tumor of the breast: A case report.

Hierarchically porous calcium phosphate scaffold with degradable PLGA microsphere network