RNA extraction-free reduced graphene oxide-based RT-LAMP fluorescence assay for highly sensitive SARS-CoV-2 detection.

Infectious diseases have always been a seriously endanger for human life and health. A rapid, accurate and ultra-sensitive virus nucleic acid detection is still a challenge to deal with infectious diseases. Here, a RNA extraction-free reduced graphene oxide-based reverse transcription-loop-mediated isothermal amplification (EF-G-RT-LAMP) fluorescence assay was developed to achieve high-throughput, rapid and ultra-sensitive SARS-CoV-2 RNA detection. The whole detection process only took ∼36 min. The EF-G-RT-LAMP assay achieves a detection limit of 0.6 copies µL-1 with a wide dynamic range of aM-pM. A large number (up to 384) of samples can be detected simultaneously. Simulated detection of the COVID-19 pseudovirus and clinical samples in nasopharyngeal swabs demonstrated a high-throughput, rapid and ultra-sensitive practical detection capability of the EF-G-RT-LAMP assay. The results proved that the assay would be used as a rapid, easy-to-implement approach for epidemiologic diagnosis and could be extended to other nucleic acid detections.

Suppression of coffee rings by controllable nanoparticle enrichment through superhydrophobicity-enabled dynamic evaporation.

Coffee rings formed by evaporation of analyte-containing droplets are widely observed in micropatterning, bio-arrays, and trace detection. The coffee-ring effect caused by contact line pinning significantly affects the detection uniformity and sensitivity. Here, we propose a simple and operable method to effectively suppress coffee rings through controllable nanoparticles aggregation by superhydrophobicity-enabled dynamic evaporation. The gold nanoparticles (AuNPs) deposition footprint formed after dynamic evaporation on an integrated superhydrophobic surface was reduced by ∼3 orders of magnitude compared to that of non-interventional evaporation. Detailed experiments, numerical simulations, and theoretical studies have revealed that substrate wettability, temperature and droplet motion behaviors play significant roles in suppressing coffee-ring effect. More critically, based on the force mechanism of AuNPs at the interface/contact line, universal mathematical models and regime maps were established to classify the different deposition modes for AuNPs under different evaporation conditions by introducing dimensionless parameter G, revealing the enrichment mechanism of AuNPs in droplets under superhydrophobicity-enabled dynamic evaporation. The accuracy of the theoretical model and enrichment mechanism was demonstrated through the single-molecule detection of rhodamine 6G with excellent sensitivity (10-17 M, enhancement factor ∼1013) and perfect uniformity (relative standard deviation ∼5.57 %), which provides a valuable guide for research and applications of nanoparticle aggregation.

What Makes a Hospital Excellent? A Qualitative Study on the Organization and Management of Five Leading Public Hospitals in China.

Purpose: To summarize the organizational and management experiences and explore the organizational theoretical model of five leading public hospitals in China. Patients and Methods: Purposive sampling was used to select five leading hospitals in different regions of China under the National Health Commission and Provincial Health Commission as study hospitals for the study. From August 2021 to March 2022, 8 leaders and 39 managers from these hospitals were surveyed using semi-structured interviews. The data and information were analyzed in four dimensions using thematic analysis and grounded theory, focused on summarizing the experiences and practices of China's leading hospitals in organizational system, culture, operations and performance management, and employee development. This study complied with the COREQ guidelines for reporting qualitative research. Results: An organizational system model of the characteristics of hospital excellence was developed using four core attributes: organizational system, organizational culture, operations and performance management, and employee development; the model was named the System-Culture-Operation-Performance-Employee (SCOPE) model. Organization and management among leaders and managers in China's leading hospitals are based on the SCOPE process, resulting in employees' well-being, patients' positive outcomes, and organizational excellence. In terms of hospital culture, while adhering to the Hippocratic Oath, the hospital is deeply influenced by traditional Chinese culture, which emphasizes "benevolence" and "love", leading all staff to adhere to "patient-centered care and service." In terms of operations management, a separate operations management department is responsible for hospital operations and performance assessment. As for employee development, the staff's sense of reverence for their profession is emphasized and a reasonable salary system and good practice environment are established to promote staff motivation. Conclusion: The SCOPE model reveals the perspectives of leaders and managers in China's leading hospitals regarding organization and management under a Chinese cultural background. These findings can complement the existing literature on hospital management systems.

Laser-Induced Graphene Superhydrophobic Surface Transition from Pinning to Rolling for Multiple Applications.

The fabrication and applications of superhydrophobic surfaces (contact angle >150°, sliding angle <10°) have attracted worldwide interest with respect to materials and devices. In this work, the laser-induced graphene (LIG) superhydrophobic surface transition from pinning to rolling via an extremely simple solvent treatment of LIG in air is reported. By adding a certain solvent (e.g., ethanol) to the surface, the LIG superhydrophobic surface changes from pinning (sliding angle = 180°) to rolling (sliding angle <6°), which is attributed to the chemically changed surface properties and surface morphology of LIG. Three applications are demonstrated with the developed superhydrophobic LIG, including surface-enhanced Raman spectroscopy, water-oil separation, and anti-icing.

Controllable Nanoparticle Aggregation through a Superhydrophobic Laser-Induced Graphene Dynamic System for Surface-Enhanced Raman Scattering Detection.

Surface-enhanced Raman scattering (SERS) is widely used for low-concentration molecular detection; however, challenges related to detection uniformity and repeatability are bottlenecks for practical application, especially as regards ultrasensitive detection. Here, through the coupling of bionics and fluid mechanics, a lotus-leaf effect and rose-petal effect (LLE-RPE)-integrated superhydrophobic chip is facilely developed using laser-induced graphene (LIG) fabricated on a polyimide film. Dense and uniform aggregation of gold nanoparticles (AuNPs) in droplets is realized through a constant contact angle (CCA) evaporation mode in the dynamic enrichment process, facilitating reliable ultrasensitive detection. The detection chip consists of two components: an LLE zone containing an ethanol-treated LIG superhydrophobic surface with a low-adhesive property, which functions as an AuNP-controllable aggregation zone, and an RPE zone containing an as-fabricated LIG superhydrophobic surface with water-solution pinning ability, which functions as a droplet solvent evaporation and a AuNP blending zone. AuNPs realize uniform aggregation during rolling on the LLE zone, and then get immobilized on the RPE zone to complete evaporation of the solvent, followed by Raman detection. Here, based on dense and uniform AuNP aggregation, the detection system achieves high-efficiency (242 s/18 µL) and ultralow-concentration (10-17 M) detection of a target analyte (rhodamine 6G). The proposed system constitutes a simple approach toward high-performance detection for chemical analysis, environmental monitoring, biological analysis, and medical diagnosis.

Mechanical Stress Induces a Transient Suppression of Cytokine Secretion in Astrocytes Assessed at the Single-Cell Level with a High-Throughput Microfluidic Chip.

Brain cells are constantly subjected to mechanical signals. Astrocytes are the most abundant glial cells of the central nervous system (CNS), which display immunoreactivity and have been suggested as an emerging disease focus in the recent years. However, how mechanical signals regulate astrocyte immunoreactivity, and the cytokine release in particular, remains to be fully characterized. Here, human neural stem cells are used to induce astrocytes, from which the release of 15 types of cytokines are screened, and nine of them are detected using a protein microfluidic chip. When a gentle compressive force is applied, altered cell morphology and reinforced cytoskeleton are observed. The force induces a transient suppression of cytokine secretions including IL-6, MCP-1, and IL-8 in the early astrocytes. Further, using a multiplexed single-cell culture and protein detection microfluidic chip, the mechanical effects at a single-cell level are analyzed, which validates a concerted downregulation by force on IL-6 and MCP-1 secretions in the cells releasing both factors. This work demonstrates an original attempt of employing the protein detection microfluidic chips in the assessment of mechanical regulation on the brain cells at a single-cell resolution, offering novel approach and unique insights for the understanding of the CNS immune regulation.

Continuous Movement Mechanism of Oil Droplets Adhered on Surfaces with Different Wettability in the Flow Field.

In this aticle, the continuous movement patterns and characteristic parameters of oil droplets on surfaces with different wettability immersed in a laminar flow field were observed, and the change rules of the geometric parameters of oil droplets under different experimental conditions were obtained. Then, the factors influencing the continuous moving behaviors of the oil droplets were analyzed, and the continuous movement velocity of the oil droplets under different experimental conditions was demonstrated. On this basis, the change law of the continuous movement velocity of oil droplets with the flow velocity was discussed. In addition, the coupling effect of the oil drops' height, surface properties, and water flow velocity on the continuous movement of oil droplets was studied, and the critical conditions for the continuous movement were obtained. According to the critical conditions, the mathematical model which described the law of continuous motion of the oil droplets adhered on surfaces with different wettability in the laminar flow field was established. The quantitative relationships among the average continuous moving velocity of oil droplets, physical properties, geometric parameters, water flow velocity, and surface wettability were obtained, which defined the necessary conditions for the uniform and accelerated movement of oil droplets, providing an important basis for choices of suitable surface wettability and flow field conditions in practical engineering applications.

Migration and Adherence of Oil Droplets on Surfaces with Different Wettability in a Laminar Flow Field.

In this article, the rising trajectories of oil droplets near the substrates of small channels in the laminar flow field were observed using a high-speed camera. Chemical modifications were made on the surfaces of the brass sheets to change the surface properties, and the controllable regulation of the superoleophilic-superoleophobic wettability gradient was achieved. The adhesion behaviors of the oil droplets on surfaces with different wettabilities at different flow velocities were observed as well. According to the adhesion behaviors of oil droplets on surfaces with different wettabilities, a mathematical model was established to analyze water film thinning and the adherence of oil droplets on the wall in the laminar flow field. Then the quantitative relationships among the adhesion times tf of oil droplets on different wetting surfaces, oil and water properties, and surface wettability were acquired.