Controllability of Graphene Oxide Doxorubicin Loading Capacity Based on Density Functional Theory.

Graphene can be used as a drug carrier of doxorubicin (DOX) to reduce the side effects of doxorubicin. However, there is limited research on the surface chemical modifications and biological effects of graphene oxide (GO). Therefore, it is necessary to explore the DOX affinity of different oxygen-containing functional groups in the graphene system. We constructed graphene system models and studied the structure and distribution of epoxy and hydroxyl groups on the carbon surface. Based on molecular dynamics simulations and density functional theory (DFT), we investigated the interaction between DOX and either pristine graphene or GO with different ratios of oxygen-containing groups. The hydroxyl groups exhibited a stronger affinity for DOX than the epoxy groups. Therefore, the DOX loading capacity of graphene systems can be adjusted by increasing the ratio of hydroxyl to epoxy groups on the carbon surface.

Bias Evaluation of the Accuracy of Two Extraoral Scanners and an Intraoral Scanner Based on ADA Standards.

The spread and application of computer-aided design/computer-aided manufacturing (CAD/CAM) technology have contributed to the rapid development of digitalization in dentistry. The accuracy of scan results is closely related to the devising subsequent treatment plans and outcomes. Professional standards for evaluating scanners are specified in the American National Standard/American Dental Association Standard 132 (ANSI/ADA No. 132). The aims of this study were to use the three samples mentioned in ANSI/ADA No. 132 and evaluate the accuracy and reproducibility of two extraoral scanners and an intraoral scanner based on the inspection standards recommended by ANSI/ADA No. 132. In this study, two trained operators used two extraoral scanners (E4, 3Shape, Denmark & SHINING DS100+, Shining, China) and an intraoral scanner (TRIOS SERIES3, 3Shape, Denmark) to perform 30 scans of each of the three samples at a temperature of 25 ± 2°C and export standard tessellation language files and used reverse engineering software to perform measurements and iterative nearest point matching experiments. The measured values obtained were compared with the reference values measured by a coordinate measuring machine (NC8107, Leader Metrology, USA). We performed a normal distribution test (Shapiro-Wilk test), the nonparametric Kruskal-Wallis test, and an independent-samples t-test to analyze the reproducibility of each scan for different models. The experimental results indicate that the trueness and precision of the two extraoral scanners and the intraoral scanner had a slight mean deviation. The trueness and precision of the three scanners on the curved surface and groove areas are poor. The accuracy and reproducibility of E4 outperformed SHINING and TRIOS. The iterative closest point matching experiment also showed good matching results. The two extraoral scanners and the intraoral scanner in this study can meet the basic clinical requirements in terms of accuracy, and we hope that digital technology will be more widely used in dentistry in the future.

Research of weak interaction between water and different monolayer graphene systems.

Weak interactions play a very important role in the fields of supramolecular chemistry, molecular physics, materials science, etc. They have a great impact on the structure of the compounds in the gas, liquid and solid phases and the mechanism of some reaction processes. In this study, we visualized the intermolecular interactions between H2O and different graphene systems through density functional theory. Because the surface of Graphene oxide (GO) has epoxy groups, hydroxyl groups, and other oxygen-containing groups. These groups are prone to hydrogen bonding with hydrogen atoms of H2O, and we further explain some of them based on the acid-base theory. Also, we obtained the components of interactions between different graphene complex and H2O by energy decomposition. Then we found that for systems with moderate strength hydrogen bonding, such as hydroxyl functional group systems, electrostatic attraction is dominant while the dispersion attraction and induction function play an auxiliary role together.

MBD3 mediates epigenetic regulation on EPAS1 promoter in cancer.

Hypoxia-inducible factor 2α (HIF2α) plays critical roles in cancer progression. Although the mechanisms of HIF2α translation and degradation have been well studied, the mechanism for HIF2α regulation at transcriptional level is still not fully understood. Here, we present evidence that DNA methylation in promoter contributes to transcription of EPAS1 coding HIF2α. Methylated CpG binding protein 3 (MBD3) contributes to the intricate regulatory mechanism. We showed that MBD3 bound to the EPAS1 promoter in breast cancer cells and amplified EPAS1 transcription through demethylating CpG located around transcriptional start site in MDA-MB-468 cells. This enabled MDA-MB-468 cells to activate HIF2α-mediated angiogenesis. However, in 7860 cells, the demethylation function of MBD3 on EPAS1 was not observed because of the poor methylated-CpG promoter. Nevertheless, depletion of MBD3 induced by shRNA decreased EPAS1 transcription and therefore decreased HIF2α-mediated cellular response in both MDA-MB-468 and 7860 cancer cells. These results indicated that the endogenous MBD3 was involved in regulating the transcription and therefore the transcriptional activities of HIF2α, suggesting that MBD3 may be a potential therapeutic target of tumor.