Department of Chemistry

Dr Rajapandiyan Panneerselvam, Assistant Professor, Department of Chemistry, and his team have developed a method using a portable Raman spectrometer to quickly identify six common pathogenic Vibrio species that can contaminate seafood. His latest research paper Intelligent convolution neural network-assisted SERS to realise highly accurate identification of six pathogenic Vibrio, has been published in the Q1 Nature Index journal Chemical Communications, having an Impact Factor of 6.0.

By using gold-silver nanoparticles, the study was able to accurately detect these harmful microorganisms. The new deep learning model called a convolutional neural network (CNN), outperformed traditional machine learning methods with a classification accuracy of 99.7%. The entire identification process only took 15 minutes. The researchers also discovered that the Raman signals emitted by Vibrio species are similar to signals from certain substances found in purine degradation, such as uric acid and adenine. This knowledge helps them explain why different Vibrio species produce slightly different Raman signals. Overall, the CNN-assisted Raman spectroscopy method offers a fast and accurate way to diagnose and identify harmful microorganisms responsible for food contamination.

Abstract

The utilisation of label-free Surface-Enhanced Raman Spectroscopy (SERS) technology enabled a comprehensive analysis of the connection between Raman signals emitted by pathogenic Vibrio microorganisms and purine metabolites. Through extensive research, a sophisticated Convolutional Neural Network (CNN) model was developed, demonstrating exceptional performance with an accuracy rate of 99.7% in the rapid identification of six common pathogenic Vibrio species within a mere 15-minute timeframe. This breakthrough offers a groundbreaking approach to pathogen identification, introducing a novel and efficient method to the field.

Practical Implementation of the Research

The practical implementation of label-free SERS technology combined with a deep learning CNN model enables rapid and accurate identification of pathogenic Vibrio microorganisms. This has important social implications, including improving public health and safety by quickly identifying and controlling outbreaks, enhancing food safety measures, and enabling real-time pathogen detection in resource-limited areas. The method’s speed and accuracy contribute to more informed decision-making, mitigating the spread of infectious diseases and ultimately creating a safer society.

Future Research Plans

Moving forward, future work in the field of label-free SERS technology for pathogen identification could focus on expanding the coverage to include a wider range of Vibrio species, increasing the diversity of the dataset used for training, conducting rigorous cross-validation and external validation studies, exploring integration with portable SERS devices for on-site detection, optimising the deep learning model for speed and efficiency, and investigating clinical and environmental applications. By pursuing these avenues, the research can further enhance the versatility, reliability, and real-world applicability of the method, leading to improved methods for rapid and accurate pathogen identification in various domains.

Collaborations

• Dr Jianfeng Li (College of Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Energy, School of Aerospace Engineering, Xiamen University, Xiamen 361005, China)
• Dr Lin Zhang (State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China)
• Dr Zehui Chen (Xiamen City Center for Disease Control and Prevention, Xiamen 361005, China)

The faculty of SRM University-AP have been awarded 10 projects worth 2.50 crores from the Science and Engineering Research Board  (SERB-SURE). Department of Science and Technology (DST) received a total of 2000 proposals, of which 466 were sanctioned. Among the 466 projects, 151 projects were awarded to Private Universities. Of the 151 projects approved to state private universities and colleges throughout India, the five-and-a-half-year young varsity was awarded 10 projects. 10 professors from various Science and Engineering Departments brought this incredible achievement to the university.

SERB-SURE is a research grant scheme initiated by the Science and Engineering Research Board (SERB) in India to provide financial support to young researchers in the early stages of their careers. The grants are intended to support research in basic and applied sciences, engineering, and technology and is typically granted for a period of three years.The SERB-SURE scheme is one of several initiatives by SERB to promote scientific research in India and support the development of a strong research community in the country.

“It is a milestone achievement that resonates with the University’s unparalleled commitment for excellence. We are striving towards research-intensive learning to build cutting-edge innovation for a transformative tomorrow”, commented Vice Chancellor, Prof. Manoj K Arora. The Executive Director-Research of SRM Group, Prof. Narayana Rao said that, “SRM University-AP has travailed hard to achieve the world-class scientific temperament that we now advocate, and this achievement is a testimonial recognition of all our efforts.” The prestigious grants were sanctioned to the faculty in the on-going domains of Quantum Kinetic Approach, Antimicrobial Resistance (AMR) Profiling and Changing of Hydroclimatic conditions in Bay of Bengal among 7 others.

Dean-SEAS, Prof. Ranjith Thapa said, “These research could be path-breaking and could offer a solution to many of the societal difficulties.” Prof. Jayaseelan Murugaiyan, Dr Sandeep Singh and Dr Pitchaiah Cherukuri of the Department of Biological Sciences; Dr Sabyasachi Chakrabortty, Dr V S Baswanth Oruganti of the Department of Chemistry; Dr Debabrata Pramanik, Dr Ravi Kumar and Dr Pankaj Bhalla  of the Department of Physics ; Dr Sandeep Kumar Verma of the Department of Mathematics; Dr Uma Maheswar Arepalli of the Department of Civil Engineering; and Dr Kousik Das of the Department of Environmental Science and Engineering were awarded the grants.

Exposure to international research opportunities promotes empirical learning at an impeccable level. International research ventures aid scholars to explore novel research avenues enabling a transformative progress for society through the field of science. The Department of Chemistry is glad to announce that Ms Jayasree K, PhD scholar, has been accepted for Short-Term Research Internship (STRI) for a period of six months from the Research Center of Environmental Medicine, Kaohsiung Medical University, Taiwan.

Ms Jayasree has been elevated in receiving the offer and delightfully keen on the new avenues she could explore through this opportunity. She is currently working in the field of surface-enhanced Raman spectroscopy (SERS). In this particular research area, her major research objective is the design and development of a novel SERS substrate for food and bioanalysis.

“My internship mentor, Prof. Vinoth Kumar, KMU University is an expert in mass spectroscopy and High-performance liquid chromatography (HPLC). Therefore, I have an option to hyphenate the Raman technique along with mass spectroscopy which leads Raman research to the next level for various applications”, commented Ms Jayasree on this incredible opportunity.

Her internship at Kaohsiung Medical University (KMU) is based on the motive of research on food and environmental toxicity which would provide guidance on her first research project in the field of food analysis.

She has offered her sincere gratitude to her supervisor, Dr Rajapandiyan JP, Department of Chemistry for his constant support and advice from the application process to proposal writing, experimental planning etc. She also thanked SRM University- AP in providing support through the process and extending travel allowance and guidance.

Ms Jayasree utilizes this great opportunity to explore and discover herself, developing both personally and professionally. Through this internship she hopes to learn new skills, expand her knowledge in the field of research and explore career options in Taiwan.

The Department of Chemistry is glad to announce that Dr Nimai Mishra, Assistant Professor, along with his research group comprising PhD scholars, Syed Akhil, Manoj Palabathuni, Subarna Biswas, Rahul Singh, have published an article titled Highly-Stable Amine-Free CsPbBr3 Perovskite Nanocrystals for Perovskite-Based Display Applications in the  journal ACS Applied Nano Materials published by the American Chemical Society, having an impact factor of 6.14.

Colloidally synthesised cesium lead halide (CsPbX3; X=Cl, Br, and I) perovskite nanocrystals (PNCs) often suffer from poor ambient and environmental stability conditions, limiting their practical applications. The commonly used surfactant oleylamine is converted to oleylammonium cation, which pulls out the halide anion from the PNCs surface, thus disrupting the nanocrystal’s structural integrity and stability.

The research group has developed a simple, completely amine-free colloidal synthesis with a hot injection method in open-atmospheric conditions and introduced bromooctane as a bromine precursor to overcome the above issues. These, as synthesized amine-free PNCs, showed a photoluminescence quantum yield (PLQY) of around 60 %, and the size of PNCs is ~25 nm. Moreover, these amine-free PNCs were highly stable in the colloidal solution and thin films for more than five months in ambient conditions, with 66% of its initial PLQY.

In addition, these PNCs have shown exceptional stability under different environmental conditions, with 44 % of initial PL even after 6 hours of water treatment and 28 % of initial PL under ethanol treatment for 120 minutes. Furthermore, it has exhibited excellent photostability for 96 hours and retained 36 % of its initial PL under ceaseless UV light irradiation at 365 nm (8 W/cm2). Additionally, these PNCs have good stability upon heat treatment and maintained 34 % of initial PL upon heating up to 90 ºC.

The research team has also successfully fabricated the green-emitting down-conversion LED using these amine-free PNCs. Thus, they visualize that these amine-free CsPbBr3 PNCs are perhaps the ideal candidates for perovskite-based display applications.

Read the full paper