Based on the excellent laboratory facilities of NPMM, we have developed a convenient, efficient, energy-saving, and environmentally friendly electrochemical processing technique to process the surface of common precious metal materials into nanotopography structures, which shows excellent optical properties and can be used as SERS sensors.[1-3]The sensitivity of the SERS sensor prepared by this method is 100 times higher than that of the current commercial SERS probes, and the cost is tens of times lower than that of the current cheapest commercial SERS sensors(Figure 1). In addition, we have designed an optical adapter (for fixing the SERS sensor) and jointly developed a portable Raman instrument (for acquiring Raman signals) for use with the SERS sensor. The whole set of portable Raman system has the characteristics of good enhancement effect, low cost, easy to use, etc. It has wide application prospects in food safety, major diseases, public safety, environmental protection, etc. The related production technology, process, design and application have been granted seven U.S. patents and four Chinese patents have been granted and won the "Invention Entrepreneurship Award" issued by China Invention Association (National Science Award Social Certificate No. 0123).
Inspired by the ancient Chinese practice of "testing poison with a silver needle", we applied our self-developed portable Raman system for food safety and major disease detection (Figure 2). Unlike conventional SERS sensors, our silver needle-based SERS sensors can be used for non-destructive rapid detection of meat products, e.g., detecting malachite green residues in fish,[4] identifying different nutrients in meat products,[1] and detecting heavy metals in meat [5]. In addition, it can also be used for the rapid detection of dairy products, the identification of the authenticity of skin care products and the identification of prohibited additivies (Figure 3), and the on-site detection of pesticide residues on the surface of vegetables and fruits.
Since 2020, the novel coronavirus disease (COVID-19) has become a global public health emergency, with more than 500 million people infected worldwide by June 2022, including more than 6.3 million deaths. We have co-opera with Guangzhou Kingmed Ltd. (which has tested more than 170 million people for the new coronavirus), and developed a SERS-based fast screening technology for the new coronavirus. A patent (ZL202111108253.7) based on this technology has been granted. In order to investigate the SERS detection mechanism of novel coronavirus disease more deeply, we collaborated with Professor Zhiwei CHEN's team from HKU to study the detection of different subtypes of the virus based on platform of the State Key Laboratory of Emerging Infectious Diseases. In addition, we have conducted blind testing of clinical samples in collaboration with the BGI group and will continue to conduct rapid bacterial screening experiments based on the portable Raman system.
Cardiovascular disease (CVD) has the highest morbidity and mortality rates in the world, it is one of the costliest diseases in the health care system. One of the critical keys to reducing CVD mortality is the development of more effective detection methods for early prediction and intervention. In collaboration with the Hong Kong Centre for Cardiovascular Health Engineering (COCHE) and with funding from the InnoHK project, we have conducted an exploratory study on early screening methods for cardiovascular diseases based on our in-house developed portable Raman system. It was found to have excellent results in detecting uric acid (one of the markers of cardiovascular disease), which can initially identify urine and blood of cardiovascular patients.
In addition, based on the high-performance, surfactant-free and selfdeveloped SERS sensor, a series of research results on the reaction mechanism have been published. [6-8]
In conclusion, the portable Raman system developed by NPMM has great potential for applications in food safety, rapid screening of major diseases, authentication of daily consumer products, and mechanistic investigation of catalytic reactions.
Figure 1 (A) Comparison of self-developed and commercial probes; (B) Portable Raman systems.
Figure 2 Application case of self-developed portable Raman system.
Figure 3 Rapid detection of zinc pyrithione in real samples.
Reference
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2. Ou, W, Shen, J, Lyu, F, Xiao, X, Zhou, B, Lu, J & Li, YY 2021, 'Facile Surfactant-, Reductant-, and Ag Salt-free Growth of Ag Nanoparticles with Controllable Size from 35 to 660 nm on Bulk Ag Materials', Chemistry—An Asian Journal, vol. 16, no. 16, pp. 2249-2252.
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6. Zhou, B, Ou, W, Shen, J, Zhao, C, Zhong, J, Du, P, Bian, H, Li, P, Yang, L, Lu, J & Li, YY 2021, 'Controlling Plasmon-Aided Reduction of p-Nitrothiophenol by Tuning the Illumination Wavelength', ACS Catalysis, vol. 11, no. 24, pp. 14898-14905.
7. Ou, W, Zhou, B, Shen, J, Zhao, C, Li, YY & Lu, J 2021, 'Plasmonic metal nanostructures: concepts, challenges and opportunities in photomediated chemical transformations', iScience, vol. 24, no. 2, 101982.
8. Ou, W, Zhou, B, Shen, J, Lo, TW, Lei, D, Li, S, Zhong, J, Li, YY & Lu, J 2020, 'Thermal and Nonthermal Effects in Plasmon-Mediated Electrochemistry at Nanostructured Ag Electrodes', Angewandte Chemie - International Edition, vol. 59, no. 17, pp. 6790–6793.