Pegylated carbon nitride nanosheets for enhanced reactive oxygen species generation and photodynamic therapy under hypoxic conditions.

The application of photodynamic therapy (PDT) is of ever-increasing importance in the treatment of malignant tumors; however, there are several major constraints that make it impossible to achieve optimal therapeutic effects. Our objective is to develop a novel photosensitizing drug for skin cancer. In the experiment, we fabricated four-arm-poly ethylene glycol modified amino-rich graphite phase carbon nitride nanosheets (AGCN-PEG), which have good stability in physiological solution and show selective accumulation in tumor cells. Under hypoxic conditions, the AGCN-PEG induced PDT can effectively inhibit growth on A431 human epidermoid carcinoma cells in vivo and in vitro. What's more, after being combined with TMPyP4, the therapeutic effect of AGCN-PEG was greatly improved.

Effect of femtosecond laser ablate ultra-fine microgrooves on surface properties of dental zirconia materials.

OBJECTIVES: Zirconia is an important dental implant material, yet it surfaces milling method is still under investigation. To explore the feasibility of laser etching in processing fine micro grooves on the surface of zirconia and to observe fine micro groove structure' influence on mouse embryonic osteoblasts, the survey was conducted. METHODS: 31 zirconia discs were made and polished to mirror surface. Then, they were divided into 3 groups: the mirror group, the femtosecond laser ablated microgroove group and the air blasted + acid etched group. Then, the surface properties of zirconia discs were analyzed by Scanning Electron Microscope/Energy Dispersive Spectrometer (SEM/EDS), X-Ray Diffraction (XRD), Atomic Force Microscope (AFM), water contact angle test and micro-Vickers hardness test. The biocompatibility of each machined zirconia was tested by cell proliferation test and SEM analyze of cell morphology. Then, the effect of these surface treatment to MC-3T3-E1's osteogenic differentiation was evaluated by Q-PCR test. RESULTS: SEM image showed that the femtosecond laser is a reliable method for forming regular-arranged microgrooves with pitch width of around 5 µm. EDS and XRD indicated that there were stable and purified tetragonal crystal system on the laser-roughened surface. AFM suggested that laser machining generated rougher surface (Ra) (271.7 ± 67.2 nm) than other groups. Furthermore, the contact angle showed laser ablated grooves induced anisotropic wetting. The micro-Vickers hardness test ascertained that laser-ablation strengthened zirconia surface. In vitro experiment showed that MC-3T3-E1 grown along the long axis of microgrooves on the first day. Besides, Real time PCR implied that osteogenesis-related gene expression OPN and ALP was much higher than the rest groups. SIGNIFICANCE: Femtosecond laser is able to machine zirconia with ultra-fine microgrooves (around 2.5 µm). These structures promoted MC-3T3-E1 cell to line along the microstructure and differentiate into osteogenic cells. Thus, femtosecond laser might be a potential processing options for zirconia micro-texturing.

Generation of a pHSPA6 gene-based multifunctional live cell sensor.

Biosensors utilizing intact live cells can report responses to certain stimuli rapidly and sensitively and have attracted a great deal of attention. The expression pattern of HSPA6, a little studied HSPA family member, has contributed to the development of multifunctional and intelligent whole-cell sensors. Herein, a new pHSPA6-based EGFP fluorescent reporter cell line was designed and developed via a CRISPR/Cas9-mediated knock-in strategy. The fluorescent reporter cell line has a precise EGFP integration site and gene copy number, and no selectable marker genes were introduced during the selection processes. Stimulation experiments with HSPA6-specific stressors indicated that EGFP fluorescent reporter cells could rapidly and effectively convert stress signals into EGFP fluorescent signals. Furthermore, cell proliferation and gene expression pattern analysis showed that the fluorescent reporter cells grew well and that both the integrated EGFP gene and the pHSPA6 gene were expressed rapidly and sensitively in response to stimulation. This study provides a new strategy for the construction of a cell model for HSPA6 expression/interaction and an intelligent live cell sensor, which can potentially be applied to numerous fields, such as those focusing on cellular models of HSPA6 signaling cascades, biomaterials, food security, environmental assessment, and drug screening.