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CUHK Develops New Microbiotic Diagnostic System

The Chinese University of Hong Kong (CUHK) has recently developed a fully automated, low cost and rapid microrobotic diagnostic system with comparable sensitivity and specificity to clinical detection methods.

Research team from CUHK is currently studying the application of this microrobotic system for multiple pathogens including SARS-CoV-2. This system has been developed by a collaborative research team led by Professor Zhang Li, Associate Professor, Department of Mechanical and Automation Engineering, Professor Margaret IP, Professor, Department of Microbiology, Professor Joseph Sung, Mok Hing Yiu Professor of Medicine and Director of the Institute of Digestive Disease, and Professor Sunny Wong, Associate Professor, Department of Medicine and Therapeutics.

Pathogen detention is essential for accurate diagnosis of diseases. The soaring demand for rapid testing was exacerbated by the COVID-19 pandemic, leading to heavy workload for laboratory personnel on an unprecedented scale. With longer the hospitalisation of patients, the patients are at higher risk of being infected by pathogens that can be fatal. Prompt clinical diagnosis is critical for patients showing signs of suspected infection.

Pressures of the COVID-19 pandemic and existing medical needs, shortages of medical manpower and resources including the laboratories may delay diagnosis, which can result in the suspension of other necessary medical procedures. Professor Margaret Ip said, “With globalisation, the spread of infectious diseases is not restricted to geographical areas. To enhance the diagnosis of infections and control, testing using automatic rapid detection systems is the general trend.”

Professor Zhang Li and his team developed an innovative microrobotic detection system, integrating the novel fluorescent microrobots with an external magnetic actuation system to accurately detect specific pathogens in a short time. The microrobotic sensing probes areG. lucidum spores coated by a layer of iron oxide nanoparticles and functionalized with carbon dots. By analysing the changes in the fluorescence signal of the microrobots under green light excitation, the system can determine the presence of pathogen in patients’ samples. The system uses an external magnetic field to remotely actuate the microrobots, speeding up the fluorescence quenching, shortening the detection time.

The first generation of microrobotic detection system, “QuickCAS”, aimed to detect Clostridium difficile, a common pathogen of nosocomial infection. The research team is now entering clinical trials, with the goal of testing in hospitals next year. In view of the pandemic disease, the team has worked closely with Professor Margaret Ip in utilising the microrobotic detection system for the COVID-19 diagnosis. The development of multiple pathogens detection using the microrobotic detection system is underway, covering common pathogens such asStreptococcus pneumoniae, Salmonella, pathogenic Escherichia coli and Helicobacter pylori, and it is expected to benefit medical institutions worldwide.

Current chemical detection methods rely on reactions between pathogen and biomolecular reagents. These bioreagents typically need to be refrigerated or frozen to preserve their structure and viability. By contrast, the microrobots are stable for transportation and storage under room temperature.

Professor Zhang Li said, “As QuickCAS uses physical detection methods, the reagents do not require refrigeration. It successfully breaks through the pain points of current chemical detection methods. In the future, medical centres in remote and poor areas or small-scale healthcare service providers will have the opportunity to provide accurate clinical diagnostic services.”

Existing methods of C. diff detection take 2 to 4 hours, in comparison, QuickCAS only takes 15 to 30 minutes to complete, and the cost has been greatly reduced from approximately HK$300 to about HK$50 per test. The automated system can not only provide hospitals with timely diagnosis and treatment for patients, but also reduce the workload and the risk of infection of medical staff during laboratory tests. Moreover, infection controls can be implemented earlier to prevent infection outbreak. Simplifying the testing procedures, can help in alleviating the pressure from the current shortage of experienced manpower. [APBN]