Metal-organic frameworks (MOFs) are porous materials with huge specific surface area and abundant active sites, which are composed of metal ions or clusters and organic ligands in the form of coordination bonds. In recent years, MOFs have been successfully applied in many fields due to their excellent physical, chemical, and biological properties. Electrochemical sensors have advantages such as economy, portability, and sensitivity, making them increasingly valued in the field of sensors. Many studies have shown that the electrode materials will affect the performance of electrochemical sensors. Therefore, the research on electrode materials is still one of the hotspots. MOFs are also commonly used to construct electrochemical sensors. However, electrochemical sensors prepared from single MOFs have shortcomings such as insufficient conductivity, low sensitivity, and poor electrochemical catalytic ability. In order to compensate for these defects, a new type of nanocomposite material with very ideal conductivity was formed by adding metal nanoparticles (MNPs) to MOFs. The combination of the two is expected to be widely applied in the field of sensors. This review summarizes the applications of various MNPs/MOFs composites in the field of electrochemical sensors and provides some references for the development of MNPs/MOFs composites-based electrochemical sensors in the future.

As a new type of "zero-dimensional" fluorescent carbon nanomaterials, carbon dots (CDs) have some unique optical and chemical properties, they are being explored for a variety of applications in bio-related fields, such as bioimaging, biosensors, and therapy. This review mainly summarizes the recent progress of CDs in bioimaging. The overview of this review can be roughly divided into two categories: (1) In vitro bioimaging based on CDs in different cells and important organelles. (2) The distribution, imaging and application of CDs in mice and zebrafish. In addition, this review also points out the potential advantages and future development directions of CDs for bioimaging, which may promote the development of CDs in the field of bioimaging.

Coronavirus disease 19 (COVID-19) is still a major public health concern in many nations today. COVID-19 transmission is now controlled mostly through early discovery, isolation, and therapy. Because of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the contributing factor to COVID-19, establishing timely, sensitive, accurate, simple, and budget detection technologies for the SARS-CoV-2 is urgent for epidemic prevention. Recently, several electrochemical DNA biosensors have been developed for the rapid monitoring and detection of SARS-CoV-2. This mini-review examines the latest improvements in the detection of SARS-COV-2 utilizing electrochemical DNA biosensors. Meanwhile, this mini-review summarizes the problems faced by the existing assays and puts an outlook on future trends in the development of new assays for SARS-CoV-2, to provide researchers with a borrowing role in the generation of different assays.

Foodborne pathogens can cause serious food safety problems. Therefore, developing fast, sensitive, and economic strategies for the determination of foodborne pathogens have become of great significance for the food safety and clinical diagnosis of foodborne diseases. Compared with the traditional methods with time-consuming, inefficient, and expensiveness, the electrochemical biosensors have the advantages of simplicity, rapidity, high sensitivity, miniaturization, and low cost, which are more conducive to rapid detection of foodborne pathogens. For the past few years, carbon nanomaterials have been frequently used to construct electrochemical-based foodborne pathogens biosensors attribute to their high conductivity, stability, and biocompatibility. Herein, this review summarizes the challenges and opportunities faced by the application of electrochemical biosensors based on carbon nanomaterials for monitoring foodborne pathogens in the recent years (2015–2020), which will open up new horizons for their development in foodborne pathogens detection.

Chemotherapy is one of the commonly used therapies for the treatment of malignant tumors. Insufficient drug-loading capacity is the major challenge for polymeric micelle–based drug delivery systems of chemotherapy. Here, the redox-responsive star-shaped polymeric prodrug (PSSP) and the dimeric prodrug of paclitaxel (PTX) were prepared. Then the dimeric prodrug of PTX (diPTX, diP) was loaded into the core of the star-shaped polymeric prodrug micelles of PSSP by hydrophobic interaction forming the redox-responsive prodrug micelles of diPTX@PSSP for intracellular drug release in tumor cells. The hydrodynamic diameter of diPTX@PSSP nanoparticles was 114.3 nm ± 2.1 (PDI = 0.219 ± 0.016), and the micelles had long-term colloidal stability and the drug-loading content (DLC) of diPTX and PTX is 16.7 and 46.9%, respectively. The prepared micelles could broke under the reductive microenvironment within tumor cells, as a result, the dimeric prodrug of diP and polymeric prodrug micelles of PSSP were rapidly disassembled, leading to the rapid release of intracellular drugs. In vitro release studies showed that under the condition of reduced glutathione (GSH) (10 mM), the release of PTX was significantly accelerated with approximately 86.6% released within 21 h, and the released PTX in cytoplasm could promote the disintegration of microtubules and induce cell apoptosis. These results indicated that the new type of this reduction-sensitive nanodrug delivery system based on dimeric prodrug@polymeric prodrug micelles would be a promising technology in chemotherapy.

Escherichia coli (E. coli) O157:H7 can cause many food safety incidents, which seriously affect human health and economic development. Therefore, the sensitive, accurate, and rapid determination of E. coli O157:H7 is of great significance for preventing the outbreak and spread of foodborne diseases. In this study, a carbon dots-Fe3O4 nanomaterial (CDs-Fe3O4)-based sensitive electrochemical biosensor for E. coli O157:H7 detection was developed. The CDs have good electrical conductivity, and the surface of carbon dots contains abundant carboxyl groups, which can be used to immobilize probe DNA. Meanwhile, the CDs can be used as a reducing agent to prepare CDs-Fe3O4 nanomaterial. The Fe3O4 nanomaterial can improve the performance of the electrochemical biosensor; it also can realize the recovery of CDs-Fe3O4 due to its magnetism. As expected, the electrochemical biosensor has excellent specificity of E. coli O157:H7 among other bacteria. The electrochemical biosensor also exhibited good performance for detecting E. coli O157:H7 with the detection range of 10–108 CFU/ml, and the detection limit of this electrochemical biosensor was 6.88 CFU/ml (3S/N). Furthermore, this electrochemical biosensor was successfully used for monitoring E. coli O157:H7 in milk and water samples, indicating that this electrochemical biosensor has good application prospect. More importantly, this research can provide a new idea for the detection of other bacteria and viruses.

目前,新型冠状肺炎(COVID-19)仍是世界各国面临的主要公共卫生问题.早发现、早隔离、早治疗是目前控制COVID-19传播的主要手段.因此,开发快速、灵敏、准确、简便、经济的新型冠状病毒(SARS-CoV-2)检测方法对于疫情的控制至关重要.本文综述了目前已有的部分快速检测手段(主要是针对核酸和蛋白检测)用于实现对SARS-CoV-2检测的最新进展.同时,本文针对已有的检测方法所面临的问题进行了总结,并对SARS-CoV-2检测方法的未来发展趋势进行了展望,以期为研究人员在新检测方法的开发方面提供借鉴作用.

Alzheimer's disease (AD) is the most common neurodegenerative disease, which seriously affects human health but lacks effective treatment methods. Amyloid β (Aβ) aggregates are considered a possible target for AD treatment. Evidence is increasingly showing that curcumin (CUR) can partly protect cells from Aβ-mediated neurotoxicity by inhibiting Aβ aggregation. However, the efficiency of targeted cellular uptake and bioavailability of CUR is very low due to its poor stability and water-solubility. In order to better improve the cell uptake efficiency and bioavailability of CUR and reduce the cytotoxicity of high-dose CUR, a novel CUR delivery system for AD therapy has been constructed based on the employment of the Fe3O4@carbon dots nanocomposite (Fe3O4@CDs) as the carrier. CUR-Fe3O4@CDs have a strong affinity toward Aβ and effectively inhibit extracellular Aβ fibrillation. In addition, CUR-Fe3O4@CDs can inhibit the production of reactive oxygen species (ROS) mediated by Aβ fibrils and the corresponding neurotoxicity in PC12 cells. More importantly, it can restore nerve damage and maintained neuronal morphology. These results indicate that the application of CUR-Fe3O4@CDs provides a promising platform for the treatment of AD.