The development of an effective method for detecting heavy-metal ions remains a serious task because of their high toxicity to public health and environments. Herein, a new electrochemical method based on a graphene aerogel (GA) and metal–organic framework (MOF) composites was developed for simultaneous detection of multiple heavy-metal ions in aqueous solutions. The GA-MOF composites were synthesized via the in situ growth of the MOF UiO-66-NH2 crystal on the GA matrix. GA not only serves as the backbone for UiO-66-NH2 but also enhances the conductivity of the composites by accelerating the electron transfer in the matrix. UiO-66-NH2 worked as a binding site for heavy-metal ions because of the interaction between hydrophilic groups and metal cations. The detection performance of the GA-UiO-66-NH2 composite-modified electrodes was determined. The developed electrochemical method can be successfully applied for individual and simultaneous detection of heavy-metal ions, namely, Cd2+, Pb2+, Cu2+,and Hg2+, in aqueous solutions with high sensitivity and selectivity. The method can also be used for simultaneous detection of Cd2+, Pb2+, Cu2+, and Hg2+ in river water and the leaching solutions of soil and vegetable with high accuracy and reliability. This work provides a new approach for simultaneous detection of multiple heavy-metal ions in practical applications.

Controllable manipulation of fluid flow is crucial for efficient particle separation, which is associated with plenty of biomedical and industrial applications. Microfluidic technologies have achieved promising progress in particle positioning depending on inertial force with or without the help of the Dean effect. Herein, we describe an inertial microfluidic system containing a spiral microchannel for various highly efficient particle separations. We demonstrated that Dean-like secondary flow can be regulated by geometric confinement in the microchannel. On the introduction of a library of micro-obstacles into the spiral microchannels, the resulting linear acceleration of secondary flow can be applied to remarkably enhance particle focusing in time and space. Further, multiple separating and sorting manipulations of particles including polymeric particles, circulating tumor cells, and blood cells, can be successfully accomplished in the dimension-confined spiral channels in a sheathless, high-throughput (typically 3 ml min), long-term (at least 4 h), and highly-efficient (up to 99.8% focusing) manner. The methodological achievement pointing to ease-of-use, effective, and high-throughput particle manipulations is useful for both laboratory and commercial developments of microfluidic systems in life and material sciences.

Background: It is well established that obesity is a disease of sustained low-grade inflammation. However, it is currently unknown if obesity plays a role in the clinical manifestations and prognosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients. In this study, we aimed to investigate whether obesity played a role in clinical manifestations and prognosis in patients infected with SARS-CoV-2. Methods: This is a retrospective multicenter clinical study. A total of 96 patients hospitalized with SARS-CoV-2 infection were enrolled from Dongguan People's Hospital, Nanfang hospital and the First Affiliated Hospital of Xiamen University between 23 January and 14 February 2020. Demographic and clinical data were extracted from medical records. Acute respiratory distress syndrome (ARDS) was defined as oxygenation index (PaO 2 /FiO 2 ) ≤ 300 mmHg. We grouped patients through the body mass index (BMI). Associations were examined using the t test, χ 2 test and multivariate logistic forward regression test. Results: Patients with BMI < 24 were significantly younger (P = 0.025) with lower creatine kinase (P = 0.013), lower diastolic pressure blood (P = 0.035), lower serum creatinine (P = 0.012), lower lactate dehydrogenase (P = 0.001) and higher platelet count (P = 0.002). The BMI level was 20.78 ± 3.15 in patients without pneumonia compared with the patients with pneumonia (23.81 ± 3.49, P = 0.001). For patients without ARDS, an average BMI level of 22.65 ± 3.53 was observed, significantly lower than patients with ARDS (24.57 ± 3.59, P = 0.022). The mean BMI was 22.35 ± 3.56 in patients experienced with relieving the clinical symptoms or stable condition by radiographic tests, lower than patients with disease exacerbation with 24.89 ± 3.17 (P = 0.001). In addition, lymphocyte count (r = − 0.23, P = 0.027) and platelet count (r = − 0.44, P < 0.001) were negatively correlated with BMI. While hemoglobin (r = 0.267, P = 0.008), creatine kinase (r = 0.331, P = 0.001), serum creatinine (r = 0.424, P < 0.001) and lactate dehydrogenase (r = 0.343, P = 0.001) were significantly positive correlated with BMI. Multivariate analysis showed that older age (OR = 1.046, P = 0.009) and BMI ≥ 24 (OR = 1.258, P = 0.005) were independent risk factors associated ICU admission while BMI ≥ 24 (OR = 4.219, P = 0.007) was independent risk factor associated with radiographic disease exacerbation.

The cellular heterogeneity of tumors has played important roles in various tumor-related research areas and applications such as the cellular biology, metastasis and clinical diagnosis of tumors. Although several microfluidics-based single-cell separation and analysis techniques have been used in research into the cellular heterogeneity of tumors, further investigation is still required for studying the effect of the biomechanical (e.g., size and deformability) heterogeneity of cells on their biological characteristics (e.g., drug resistance and tumor-initiating features). Here, we established an integrated microfluidic platform for the construction of single-cell arrays and analysis of drug resistance. Using this device, high-throughput single-cell arrays could be easily obtained according to the biomechanical (size and deformability) heterogeneity of cells. To demonstrate the capability of the microfluidic platform, a proof-of-concept experiment was implemented by determining the vincristine resistance of single glioblastoma cells with different biomechanical properties. The results indicated that the biomechanics of tumor cells had significant implications for cell drug resistance; that is, small and/or more deformable tumor cells had higher drug resistance than large and/or less deformable tumor cells. This device provides a new approach for the isolation of single cells according to the different biomechanical properties of cells. Also, it possesses practical potential for studies of tumors on a single-cell level.