Nephrotoxicity Evaluation of Indium Phosphide Quantum Dots with Different Surface Modifications in BALB/c Mice

Exploration of risk analysis and elimination methods for a Cr(VI)-removal recombinant strain through a biosafety assessment in mice

Though recombinant strains are increasingly recognized for their potential in heavy metal remediation, few studies have evaluated their safety. Moreover, biosafety assessments of fecal-oral pathway exposure at country as well as global level have seldom analyzed the health risks of exposure to microorganisms from a microscopic perspective. The present study aimed to predict the long-term toxic effects of recombinant strains by conducting a subacute toxicity test on the chromium-removal recombinant strain 3458 and analyzing the gut microbiome. The available disinfection methods were also evaluated. The results showed that strain 3458 induced liver damage and affected renal function and lipid metabolism at 1.0 × 1011 CFU/mL, which may be induced by its carrier strain, pET-28a. Strain 3458 poses the risk of increasing the number of pathogenic bacteria under prolonged exposure. When 500 mg L-1 chlorine-containing disinfectant or 250 mg L-1 chlorine dioxide disinfectant was added for 30 min, the sterilization rate exceeded 99.9 %. These findings suggest that existing wastewater disinfection methods can effectively sterilize strain 3458, ensuring its application value. The present study can serve a reference for the biosafety evaluation of the recombinant strain through exposure to the digestive tract and its feasibility for application in environmental pollution remediation.

Metal-polyphenol networks-modified tantalum plate for craniomaxillofacial reconstruction

Using three-dimensional (3D) printing technology to make the porous tantalum plate and modify its surface. The physicochemical properties, cytocompatibility, antioxidant capacity, and histocompatibility of the modified materials were evaluated to prepare for the repair of craniomaxillofacial bone defects. The porous tantalum plates were 3D printed by selective laser melting technology. Tantalum plates were surface modified with a metal polyphenol network. The surface-modified plates were analyzed for cytocompatibility using thiazolyl blue tetrazolium bromide and live/dead cell staining. The antioxidant capacity of the surface-modified plates was assessed by measuring the levels of intracellular reactive oxygen species, reduced glutathione, superoxide dismutase, and malondialdehyde. The histocompatibility of the plates was evaluated by animal experiments. The results obtained that the tantalum plates with uniform small pores exhibited a high mechanical strength. The surface-modified plates had much better hydrophilicity. In vitro cell experiments showed that the surface-modified plates had higher cytocompatibility and antioxidant capacity than blank tantalum plates. Through subcutaneous implantation in rabbits, the surface-modified plates demonstrated good histocompatibility. Hence, surface-modified tantalum plates had the potential to be used as an implant material for the treatment of craniomaxillofacial bone defects.

An update on the biological effects of quantum dots: From environmental fate to risk assessment based on multiple biological models

Quantum dots (QDs) are zero-dimension nanomaterials with excellent physical and chemical properties, which have been widely used in environmental science and biomedicine. Therefore, QDs are potential to cause toxicity to the environment and enter organisms through migration and bioenrichment effects. This review aims to provide a comprehensive and systematic analysis on the adverse effects of QDs in different organisms based on recently available data. Following PRISMA guidelines, this study searched PubMed database according to the pre-set keywords, and included 206 studies according to the inclusion and elimination criteria. CiteSpace software was firstly used to analyze the keywords of included literatures, search for breaking points of former studies, and summarize the classification, characterization and dosage of QDs. The environment fate of QDs in the ecosystems were then analyzed, followed with comprehensively summarized toxicity outcomes at individual, system, cell, subcellular and molecular levels. After migration and degradation in the environment, aquatic plants, bacteria, fungi as well as invertebrates and vertebrates have been found to be suffered from toxic effects caused by QDs. Aside from systemic effects, toxicity of intrinsic QDs targeting to specific organs, including respiratory system, cardiovascular system, hepatorenal system, nervous system and immune system were confirmed in multiple animal models. Moreover, QDs could be taken up by cells and disturb the organelles, which resulted in cellular inflammation and cell death, including autophagy, apoptosis, necrosis, pyroptosis and ferroptosis. Recently, several innovative technologies, like organoids have been applied in the risk assessment of QDs to promote the surgical interventions of preventing QDs' toxicity. This review not only aimed at updating the research progress on the biological effects of QDs from environmental fate to risk assessment, but also overcame the limitations of available reviews on basic toxicity of nanomaterials by interdisciplinarity and provided new insights for better applications of QDs.

InP/ZnS quantum dots cause liver damage in rare minnow (Gobiocypris rarus) larvae

InP/ZnS quantum dots (QDs) are widely used in biomedical imaging and light-emitting component manufacturing industries, but there are few studies on their biological toxicity. In this study, we conducted experiments with rare minnow larvae and found that InP/ZnS QDs can cause liver damage. InP/ZnS QDs appeared only in the intestine of larvae and were not enriched in other parts of the larvae. The activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AKP) increased, while the decrease in bile acid. InP/ZnS QDs caused hepatic cell nuclear lysis, abnormal cytoplasmic staining, and mitochondrial cristae reduction, swelling, and fragmentation. RNA-sequencing results revealed that InP/ZnS QDs exposure treatment affected the expression of genes involved in lipid metabolism, sterol synthesis, bile acid synthesis and other pathways. The excessive production of reactive oxygen species (ROS) induced by InP/ZnS QDs may be the main source of toxicity.

Exploration of Maternal and Fetal Toxicity Risks for Metronidazole-Related Teratogenicity and Hepatotoxicity through an Assessment in Albino Rats

Metronidazole is the primary antimicrobial drug for treating acute and chronic vaginal pathogens during pregnancy; however, there has been insufficient research on placental disorders, early pregnancy loss, and preterm birth. Here, the potential activity of metronidazole on pregnancy outcomes was investigated. 130 mg/kg body weight of metronidazole was orally given individually to pregnant rats on gestation days 0-7, 7-14, and 0-20. Pregnancy outcome evaluations were carried out on gestation day 20. It was demonstrated that metronidazole could induce maternal and fetal hepatotoxicity. There is a significant increase in the activities of maternal hepatic enzymes (ALT, AST, and ALP), total cholesterol, and triglycerides compared with the control. These biochemical findings were evidenced by maternal and fetal liver histopathological alterations. Furthermore, metronidazole caused a significant decrease in the number of implantation sites and fetal viability, whereas it caused an increase in fetal lethality and the number of fetal resorptions. In addition, a significant decrease in fetal weight, placental weight, and placental diameter was estimated. Macroscopical examination revealed placental discoloration and hypotrophy in the labyrinth zone and the degeneration of the basal zone. The fetal defects are related to exencephaly, visceral hernias, and tail defects. These findings suggest that the administration of metroniazole during gestation interferes with embryonic implantation and fetal organogenesis and enhances placental pathology. We can also conclude that metronidazole has potential maternal and fetal risks and is unsafe during pregnancy. Additionally, it should be strictly advised and prescribed, and further consideration should be given to the associated health risks.

Transepithelial transport and cytoprotection of novel antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham

As a traditional fermented meat product, dry-cured Xuanwei ham could be a rich source of bioactive peptides. This study intended to investigate the transepithelial transport and cytoprotection of antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham. Through ultrafiltration and gel filtration chromatography after simulated digestion, five new antioxidative cell-penetrating peptides (CPPs) with 16-27 amino acid residues were identified, and protective effects of the pretreatment with GHYTEGAELVDSVLDVVRK (GK-19) and TDEFQLHTNVNDGTEFGGSIYQK (TK-23) on H₂O₂-induced damaged HepG2 cells were investigated. The results showed that the peptide TK-23 at 0.5 mg mL^-1 showed a good antioxidant activity through upregulating the activity of antioxidant enzymes (CAT, SOD and GR) and decreasing the MDA level in H₂O₂-induced damaged HepG2 cells with a better protective effect compared to GSH. Our observations of novel antioxidant CPPs with 16-27 amino acid residues could enrich the antioxidative CPP database, and these findings could provide data support for further study of CPPs.

Photoactivated Indium Phosphide Quantum Dots Treat Multidrug-Resistant Bacterial Abscesses In Vivo

The increasing prevalence of drug-resistant bacterial strains is causing illness and death in an unprecedented number of people around the globe. Currently implemented small-molecule antibiotics are both increasingly less efficacious and perpetuating the evolution of resistance. Here, we propose a new treatment for drug-resistant bacterial infection in the form of indium phosphide quantum dots (InP QDs), semiconductor nanoparticles that are activated by light to produce superoxide. We show that the superoxide generated by InP QDs is able to effectively kill drug-resistant bacteria in vivo to reduce subcutaneous abscess infection in mice without being toxic to the animal. Our InP QDs are activated by near-infrared wavelengths with high transmission through skin and tissues and are composed of biocompatible materials. Body weight and organ tissue histology show that the QDs are nontoxic at a macroscale. Inflammation and oxidative stress markers in serum demonstrate that the InP QD treatment did not result in measurable effects on mouse health at concentrations that reduce drug-resistant bacterial viability in subcutaneous abscesses. The InP QD treatment decreased bacterial viability by over 3 orders of magnitude in subcutaneous abscesses formed in mice. These InP QDs thus provide a promising alternative to traditional small-molecule antibiotics, with the potential to be applied to a wide variety of infection types, including wound, respiratory, and urinary tract infections.