Many kinds of antibacterial coatings have been designed to prevent the adherence of bacteria onto the surface of a fixed orthodontic device of brackets. However, the problems such as weak binding force, undetectable, drug resistance, cytotoxicity and short duration needed to be solved. Thus, it has great value in developing novel coating methods with long-term antibacterial and fluorescence properties according to the clinical application of brackets. In this study, we synthesized blue fluorescent carbon dots (HCDs) using the traditional Chinese medicinal honokiol, which could cause irreversible killing effects on both gram-positive and gram-negative bacteria through positive charges on the surface and inducing reactive oxygen species (ROS) production. Based on this, the surface of brackets was serially modified with polydopamine and HCDs, taking advantage of the strong adhesive properties as well as the negative surface charge of polydopamine particles. It is found that this coating exhibits stable antibacterial properties in 14 days with good biocompatibility, which can provide a new solution and strategy to solve the series of hazards caused by bacterial adhesion on the surface of orthodontic brackets. Graphical Abstract

With the excellent ability to transform near-infrared light to localized visible or UV light, thereby achieving deep tissue penetration, lanthanide ion-doped upconversion nanoparticles (UCNP) have emerged as one of the most striking nanoscale materials for more effective and safer cancer treatment. Up to now, UCNPs combined with photosensitive components have been widely used in the delivery of chemotherapy drugs, photodynamic therapy and photothermal therapy. Applications in these directions are reviewed in this article. We also highlight microenvironmental tumor monitoring and precise targeted therapies. Then we briefly summarize some new trends and the existing challenges for UCNPs. We hope this review can provide new ideas for future cancer treatment based on UCNPs.

DNA fragmentation into internucleosomal fragments is the best recognized biochemical event of apoptosis. Two major caspase pathways have been identified in the signal transduction leading to DNA fragmentation: the receptor pathway and the mitochondrial pathway. DNA fragmentation factor (DFF) has been identified as a major apoptotic endonuclease in the internucleosomal DNA fragmentation process. However, the potential roles of caspases and DFF in internucleosomal DNA fragmentation induced by specific stimuli still need to be investigated since caspaseindependent pathways and nuclease(s) other than DFF also play important roles during this process. In the present study, we investigated the activity of GP7 (4-[4"-(2",2",6",6"-tetramethyl-l"-piperidinyloxy) amino]-4'-demethyl epipodophyllotoxin), a new spin-labeled derivative of podophyllotoxin semi-synthesized by our university, to induce apoptosis of the human leukemia cell line NB4. GP7 induced the release of cytochrome-c from mitochondria, activations of caspase-3,-8, and-9, cleavage of DFF45/inhibitor of caspase-activated DNase, activation of DFF40/caspase-activated DNase, and apoptotic DNA fragmentation in NB4 cells. The broadspectrum caspase inhibitor zVAD-fmk abrogated GP7induced caspase-3,-8, and-9 activations but could not inhibit GP7-induced apoptotic DNA fragmentation in NB4 cells. Our findings suggest that GP7-induced apoptotic DNA fragmentation in NB4 cells is independent of caspase activation and DFF, although they are closely involved in this process.

Human pluripotent stem cells (hPSCs) have the potential of long‐term self‐renewal and differentiation into nearly all cell types in vitro. Prior to the downstream applications, the design of chemically defined synthetic substrates for the large‐scale proliferation of quality‐controlled hPSCs is critical. Although great achievements have been made, Matrigel and recombinant proteins are still widely used in the fundamental research and clinical applications. Therefore, much effort is still needed to improve the performance of synthetic substrates in the culture of hPSCs, realizing their commercial applications. In this review, we summarized the design of reported synthetic substrates and especially their limitations in terms of cell culture. Moreover, much attention was paid to the development of promising peptide displaying surfaces. Besides, the biophysical regulation of synthetic substrate surfaces as well as the three‐dimensional culture systems were described.

The success rate of dental implants is limited by peri-implant infection and insufficient osseointegration. Therefore, reducing the occurrence of peri-implantitis and promoting osseointegration are in demand. A roughened surface has commonly been applied to improve the osseointegration of implants, but it will accelerate the attachment of bacteria. We have developed novel antibiotic-decorated titanium (Ti) surfaces by the immobilization of dopamine and cefotaxime sodium (CS) simultaneously. Moreover, the surface roughness of the polydopamine (PDA)/CS coating was controlled by the changes in polymerization times as determined by atomic force microscopy. Then, all antibiotic-grafted Ti surfaces could effectively prevent the adhesion and proliferation of both Escherichia coli and Streptococcus mutans in comparison to the pristine control. For the culture and osteogenic differentiation of human umbilical mesenchymal stem cells (hUMSCs) on the substrate surface, PDA/CS coating with polymerization times less than 30 min showed acceptable biocompatibility, but the upregulation of marker genes and proteins was detected when the polymerization time was more than 30 min. Moreover, the best calcium deposition results were found in the 30 min PDA/CS group with or without the addition of osteogenic factors. Therefore, our PDA/CS coating with a polymerization time of 30 min holds great potential to design dental implants with dual bacteriostatic and osteogenic properties.