Droplet magnetic-controlled microfluidic chip integrated nucleic acid extraction and amplification for the detection of pathogens and tumor mutation sites

Ultra-simple nucleic acid extraction using a polystyrene microplastic particles-thermal lysis system for rapid detection of pathogen in nasal mucus

Respiratory infections are a leading cause of death and disability globally and have become an important issue of public concern. Nucleic acid amplification test (NAAT) has been recognized as the gold standard for respiratory infection diagnosis, and played a critical role in epidemic control during the COVID-19 pandemic. However, the laborious nucleic acid extraction limits the application of NAAT in the on-site respiratory infection diagnosis, an effective approach for disease control and prevention. Herein, a polystyrene microplastic particle (PSMP)-thermal lysis system was established to extract nucleic acids from nasal mucus in 4 min simply and rapidly without sacrificing sensing performance. The PSMP-thermal lysis system showed a strong protein adsorption capacity, by which nearly eliminating the interference of protein content in nasal mucus on amplification reaction. Moreover, the PCR using this PSMP-thermal lysis system showed excellent selectivity and anti-jamming ability, as well as the high sensitivity comparable to that using commercial kits based on commonly used solid-phase extraction in detecting target pathogens in sticky nasal mucus with protein content of 25.11 μg/μL. Furthermore, the practical use investigation indicated the PCR assay using this system could accurately identify respiratory infection patients by detecting corresponding pathogens in clinical nasal mucus samples. This PSMP-thermal lysis system has the potential for pathogen detection in various respiratory secretions and is anticipated to substantially simplify molecular diagnosis of respiratory infections.

EB-YOLO:An efficient and lightweight blood cell detector based on the YOLO algorithm

Blood cell detection is an important part of medical diagnosis. Object detection is trending for blood cell analysis, with research focusing on high-precision neural network models. However, these models have complex architectures and high computational costs. They cannot achieve rapid detection on low-end devices. Although lightweight models can greatly enhance the detection speed and achieve the real-time detection on low-end devices, their accuracy is poor in complex tasks. The development of efficient and highly accurate blood cell detectors for environments with limited computational resources is of great practical value. This study proposes an Efficient Blood Cell Detector based on YOLO (EB-YOLO) for blood cell detection. The model uses ShuffleNet as the backbone network for feature extraction to reduce the number of parameters and computational load. It incorporates the Convolutional Block Attention Module (CBAM) to enhance feature representation. In the neck network, Adaptive Spatial Feature Fusion (ASFF) is used for feature integration to improve multi-scale target feature extraction. Depth-wise separable convolution replaces standard convolution to reduce parameters while maintaining performance. Experimental results on the BCCD dataset show that the proposed model achieves 92.1 % mAP@50 %, the computational complexity is only 0.9 GFLOPs, and the number of parameters is 0.289M. The comparison results of the inference speed on Raspberry PI 5 show that the detection speed of the model is better than the classic YOLO algorithm model. The proposed method successfully balances lightweight design and high accuracy, which shows promise for deployment on low-end embedded systems.

CRISPR Digital Sensing: From Micronano-Collaborative Chip to Biomolecular Detection

The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) sensing technology proved to be valuable during the COVID-19 pandemic through its sensitivity, specificity, robustness, and versatility. However, issues such as overreliance on amplification, susceptibility to false positives, lack of quantification strategies, and complex operation procedures have hindered its broader application in bioanalysis and clinical diagnostics. The collision between micronano-collaborative chips and CRISPR technology has effectively addressed these bottlenecks, offering innovative solutions for diagnosis and treatment. Unlike conventional micronano chips, micronano digital chips enhance CRISPR's response to trace amounts of target molecules by leveraging highly controllable local environments and compartmentalized microreactors. This advancement improves detection efficiency and revolutionizes traditional in vitro bioanalytical processes. First, the working principles, fabrication techniques, and performance metrics of CRISPR-based digital droplet microfluidics and microarray chips are examined. Then, the applications of CRISPR digital sensing chips in bioassays are reviewed, emphasizing their importance in advancing in vitro detection systems for gene editing. Finally, the prospects of CRISPR digital sensing technology are explored, particularly its potential for body surface biomonitoring and its broader development opportunities in the biomedical field.

Construction of a microfluidic SELEX platform for efficient screening of advanced glycation end products aptamer

Aptamers, as a kind of recognition molecules with stable nature and excellent binding ability, are usually obtained by systematic evolution of ligands by exponential enrichment (SELEX). However, the traditional SELEX suffers from the problems of low screening efficiency as well as excessive number of screening rounds, making the screening a cumbersome process, which greatly restricts the application and development of aptamers. Here, a microfluidic SELEX platform based on capture SELEX was designed and developed to make the screening more integrated and convenient. Nε-carboxymethyl lysine (CML) and Nε-carboxyethyl lysine (CEL), were selected as targets for screening, and candidate aptamers were identified after eight rounds of screening using the microfluidic SELEX platform. Following isothermal titration calorimetry (ITC) and SYBR GREEN I (SGI) analysis, aptamer S2 was identified with the highest affinity and specificity. Aptamer S2 was further optimized based on the binding sites explored by molecular docking. Eventually, the truncated aptamer S2-40 was obtained, which was superior to S2 in terms of affinity and specificity with dissociation constant (Kd) of 6.65 ± 3.07 μM (ITC) and 42.1 ± 9.34 nM (SGI), respectively. This indicated that the microfluidic SELEX platform offers a more integrated and convenient approach to aptamer screening.

Multiplexed Pathogenic Bacteria Detection via a Two-Dimensional Encoded Fluorescent Microsphere System

We developed an advanced microscopy imaging platform enabling amplification-free, multiplex detection of pathogenic bacteria in food and clinical samples, eliminating the need for DNA extraction. This platform leverages two-dimensional encoded polystyrene (PS) microspheres and an Argonaute-based decoding system to create multiplexed signal libraries. Each PS microsphere probe, encoded with spectrally distinct fluorophores and differing particle sizes, achieves high fluorescence through a tetrahedral DNA-enhanced hybridization chain reaction (TDNA-HCR), significantly enhancing signal intensity and reducing reaction time by 67%. Pathogenic bacteria identification relies on aptamer-specific recognition, which transduces pathogenic bacteria presence into guide DNA (gDNA) signals that activate Clostridium butyricum Argonaute (CbAgo) for precise DNA cleavage, encoding pathogenic bacteria type and concentration in the color, size, and count of fluorescent PS probes. A custom computer vision-powered algorithm processes these signals, offering sensitive detection at 102 CFU/mL within 1.5 h, demonstrating significant potential for food safety and clinical diagnostic applications.

An efficient, high-throughput enrichment system for the rapid detection of E. coli at low concentrations in water

Certain virulent strains of Escherichia coli (E. coli), notably the enterohemorrhagic serotype O157:H7, are recognized for causing diarrhea, gastroenteritis, and a range of illnesses that pose significant risks to public health and the safety of drinking water supplies. Early detection and management of E. coli, particularly at low concentrations, are critical for identifying potential sources of contamination. This proactive approach can prevent the spread of diseases, ensure the safety of drinking water, and maintain the hygiene of consumable products. However, detecting low concentrations of E. coli in water samples presents challenges, such as reduced sensitivity, prolonged analysis times, complex sample preparation, susceptibility to interferences, cost limitations, and result variability. To overcome these challenges, we developed an enrichment system that rapidly and efficiently concentrates low-concentration E. coli samples. This system consists of two modules: a primary enrichment module and a secondary enrichment module. The primary enrichment module uses Dean flow technology to enhance E. coli recovery through lateral flushing, achieving recovery rates between 82.7 % and 92.7 %. The secondary enrichment module employs double membrane filtration to further concentrate E. coli. This two-stage enrichment process can amplify E. coli concentrations up to 1000-fold, achieving a recovery rate of 61.8 % within just 30 min. This system enables ultra-high multiplicity enrichment of E. coli from low concentrations in water samples, providing small volumes of highly concentrated samples necessary for subsequent precise detection based on droplet microfluidic technology. The development of this system offers significant benefits for the enrichment and rapid detection of pathogenic bacteria in environmental samples.

Generation, manipulation, detection and biomedical applications of magnetic droplets in microfluidic chips

Microfluidic systems incorporating magnetic droplets have emerged as a focal point of significant interest within the biomedical domain. The allure of these systems lies in their capacity to offer precise control, enable contactless operation, and accommodate minimal sample concentration requirements. Such remarkable features serve to mitigate errors arising from human operation and other factors during cell or molecular detection. By providing innovative solutions for molecular diagnostics and immunoassay applications, magnetic droplet microfluidics enhance the accuracy and efficiency of these procedures. This review undertakes a comprehensive examination of the research progress in microfluidic systems centered around magnetic droplets. It adheres to a sequential presentation approach, commencing from the fundamental operation principles, specifically the generation of magnetic droplets on the microfluidic chip, and proceeding to their transmission and mixing within the microchannel via an array of operating techniques. Additionally, the relevant detection technologies associated with magnetic drop microfluidics and their numerous applications within the biomedical field are systematically classified and reviewed. The overarching objective of this review is to spotlight key advancements and offer valuable insights into the future trajectory of this burgeoning field.

Implementation of Rapid Nucleic Acid Amplification Based on the Super Large Thermoelectric Cooler Rapid Temperature Rise and Fall Heating Module

In the rapid development of molecular biology, nucleic acid amplification detection technology has received more and more attention. The traditional polymerase chain reaction (PCR) instrument has poor refrigeration performance during its transition from a high temperature to a low temperature in the temperature cycle, resulting in a longer PCR amplification cycle. Peltier element equipped with both heating and cooling functions was used, while the robust adaptive fuzzy proportional integral derivative (PID) algorithm was also utilized as the fundamental temperature control mechanism. The heating and cooling functions were switched through the state machine mode, and the PCR temperature control module was designed to achieve rapid temperature change. Cycle temperature test results showed that the fuzzy PID control algorithm was used to accurately control the temperature and achieve rapid temperature rise and fall (average rising speed = 11 °C/s, average falling speed = 8 °C/s) while preventing temperature overcharging, maintaining temperature stability, and achieving ultra-fast PCR amplification processes (45 temperature cycle time < 19 min). The quantitative results show that different amounts of fluorescence signals can be observed according to the different concentrations of added viral particles, and an analytical detection limit (LoD) as low as 10 copies per μL can be achieved with no false positive in the negative control. The results show that the TEC amplification of nucleic acid has a high detection rate, sensitivity, and stability. This study intended to solve the problem where the existing thermal cycle temperature control technology finds it difficult to meet various new development requirements, such as the rapid, efficient, and miniaturization of PCR.

A point-of-care testing platform for on-site identification of genetically modified crops

Genetically modified (GM) food is still highly controversial nowadays. Due to the disparate policies and attitudes worldwide, demands for a rapid, cost-effective and user-friendly GM crop identification method are increasingly significant for import administration, market supervision, etc. However, as the most-recognized methods, nucleic acid-based identification approaches require bulky instruments, long turn-around times and trained personnel, which are only suitable in laboratories. To fulfil the urgent needs of on-site testing, we develop a point-of-care testing platform that is able to identify 12 types of GM crops in less than 40 minutes without using laboratory settings. Our system integrates sample pre-treatment modules in a microfluidic chip, performs DNA amplification via a battery-powered portable kit, and presents results via eye-recognized colorimetric change. A paraffin-based reflow method and a slip plate-based fluid switch are developed to encapsulate and release amplification primers in individual microwells on demand, thus enabling identification of varied targets simultaneously. Our system offers an efficient, affordable and convenient tool for GM crop identification, thus it will not only benefit customs and market administration bureaus, but also satisfy demands of numerous consumers.