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.

/pdf/biomedical-applications-of-biodegradable-polymers-2db9gcyzxw.pdf

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

In this study, the origin and transport properties of high mobility carriers of two-dimensional electron gas (2DEG) at ZnMgO/ZnO interface have been investigated. It is found that the observed experimental dependence of carrier sheet density of 2DEG on ZnMgO thickness and Mg composition exhibits an excellent agreement with the theoretical calculations based on the surface charge model. It indicates that the mobile electrons in 2DEG are originated from the donor-like surface states. Moreover, the anomalous periodicity of Shubnikov-de Haas oscillations has been observed and the partial spin polarization feature of 2DEG has also been demonstrated, which exhibits the promising development in oxide spintronics applications. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Origin and transport properties of two-dimensional electron gas at ZnMgO/ZnO interface grown by MOVPE

Tensile-strained Ge photodetector is realized on Si-substrate using novel SiSiGe compliant layer with two-step Ge-process. Monolithic integration of p-i-n detectors with low dark current (0.4 nA), responsivity (190 mA/W) and high speed (5 GHz) on Ge-CMOS platform is demonstrated, with Ge pMOSFET showing 2X Si hole mobility.

Integration of Tensile-Strained Ge p-i-n Photodetector on Advanced CMOS Platform

Hydroxyapatite (HA) is well-known as one of the excellent bone repair biomaterials because of its chemical similarity with biological apatite. However, weak bioactivity obstructs its application. A...

Enhancing the Cell-Biological Performances of Hydroxyapatite Bioceramic by Constructing Silicate-Containing Grain Boundary Phases via Sol Infiltration.

The forming of Al2O3 ceramics was carried out by the colloidal in-situ consolidation using modified starch in this work. The effects of the modified starch content in the alumina suspensions on their rheological behavior, consolidation, microstructure and properties of the green bodies were investigated. The different shape and high relative density of ceramic green bodies were achieved by this method. The results indicated that the alumina suspensions with modified starch were easier to cast due to their low viscosity and high fluidity. After drying, the linear shrinkage of the green bodies was low, ranging between about 1.5% and 2.2% and their bulk density was higher than 57% of the theoretical density. The maximum bending strength of the dried green bodies reached to 8.2 MPa and the microstructure of the green bodies was uniform with a narrow unimodal distribution of pore size. It is concluded that the colloidal in-situ consolidation casting using modified starch can perform near-net shaping of ceramic components with high-performance and it is a potential forming technique for ceramics.

Colloidal In-Situ Consolidation Forming of Al2O3 Ceramics Using Modified Starch

The generation of p-type GaN through ion implantation is an attractive proposition in the massive production of GaN-based bipolar devices, whereas the removal of implantation induced lattice disturbances and defects is a difficult exercise and hampers the conversion of conductivity in GaN. Pulsed laser annealing is an effective annealing technique to recover lattice crystallinity and activate dopants with the preserved implanted profile. In this work, the effect of pulsed laser annealing on structural and optical recovery in high-dose magnesium (Mg) ion-implanted GaN has been investigated. The structural evolution and vibrational dynamics indicate an obvious structural recovery and partial strain release of Mg-implanted GaN during the pulsed laser annealing process, with a threshold laser fluence of 400 mJ/cm2, while rough surface structures are a result of the regrowth mechanism similar to liquid phase epitaxy. The enhanced donor–acceptor transition at 3.35 eV after pulsed laser irradiation is a sign of the effective activation of Mg from interstitial sites into the substitution of Ga ions. These results suggest that further optimization of the laser annealing technique has promising potential to manipulate the p-type conductivity of Mg-implanted GaN and to be implemented in GaN bipolar devices for practical applications.

Jiandong Ye

Papers

Origin and transport properties of two-dimensional electron gas at ZnMgO/ZnO interface grown by MOVPE

Integration of Tensile-Strained Ge p-i-n Photodetector on Advanced CMOS Platform

Enhancing the Cell-Biological Performances of Hydroxyapatite Bioceramic by Constructing Silicate-Containing Grain Boundary Phases via Sol Infiltration.

Colloidal In-Situ Consolidation Forming of Al2O3 Ceramics Using Modified Starch

Property manipulation through pulsed laser annealing in high dose Mg-implanted GaN