A research group from the Indian Institute of Technology Guwahati, have developed a miniaturized nanochip from laboratory waste material for the detection of hydrogen peroxide in blood samples. The team, led by Professor Pranjal Chandra including the Ph.D. students; Buddhadev Purohit, Kuldeep Mahato, and Ashutosh Kumar of the Department of Biosciences and Bioengineering, IITG has recently published the research work in Microchimica Acta.

Biomarkers are molecules or chemical entities, which are found in the body at different concentrations under the diseased conditions than the healthy persons. The altered concentrations enable us to know the onset as well as the progression of the diseases inside the body. Hydrogen peroxide, a biomarker is very crucial for the growth and development of the human body as it is associated with various metabolic processes. It is generated as a byproduct of several enzymes and is found in the blood in the range of nanomole to subnanomole. But, when the concentration of hydrogen peroxide rises, it binds to the proteins in its periphery and alters their activity. It has been reported earlier that the concentration of hydrogen peroxide in the blood rises to micromolar level (10-100 times more than healthy individuals) under various fatal diseases like cancer, diabetes, cardiovascular diseases, neurodegenerative disorders, etc. Therefore, by detecting the fluctuation of hydrogen peroxide levels, the occurrence and progression of such diseases can be accessed. So, the analytical methods, which can detect the level of hydrogen peroxide in blood or other biological samples has tremendous large scale implications. The traditional detection systems are able to detect the presence of hydrogen peroxide, but they majorly suffer due to the involvement of sophisticated instruments, trained personals, multistep time-consuming protocols, and use of various chemicals. In order to address these problems, the scientists at IIT Guwahati has developed for the first time a sputtering assisted label-free biosensing approach using a laboratory waste material for the detection of hydrogen peroxide in biological/chemical samples. The developed nanochip in the laboratory contained nanostructures with fern-like morphology, known as dendrites, were tested for their potential beneficial use. To characterize and optimize the development of the nanostructure chip, electron microscopy is an inseparable method, where the metallic sputtering of particles is essential. However, such sputtering introduces various defects on the nanochip, eventually made it trash.

In this work, the detection system used the hydrogen peroxide cleaving action (commonly termed as peroxidase activity) by the sputtered dendritic nanostructures in the nanochip. The developed sensor based on such sputtering was capable of detecting hydrogen peroxide in merely = 1.0 s. The total time required to fabricate the final sensor form the raw materials was less than 30 minutes. The developed nanochip was able to detect hydrogen peroxide in a wider detection range (10^-12 to 10 ^-5 molar), hence it can be applied for various clinical conditions where the levels of hydrogen peroxide fluctuate greatly. The sensor nanochip also found to detect hydrogen peroxide efficiently in the presence of various other molecules commonly found in biological samples like glucose, urea, uric acid, and various amino acids. The sensor was also able to detect the level of hydrogen peroxide in the blood samples with 96% accuracy. The sensor chip can be used for sensing application multiple times without losing its efficiency. 

Professor Chandra, who leads the research group told that the developed nanochip is able to detect hydrogen peroxide in clinical settings in = 1.0 s with very high efficiency and precision. It can be further used for various clinically important experiments where the measurements of hydrogen peroxide content are important. In the future, the nanochip can be integrated with various miniaturized interfaces like smartphones to develop portable handheld devices using the sensing principles demonstrated in this work. Further, the system can also be modified to use in other clinically important samples such as serum, urine, tear, etc. to measure hydrogen peroxide level. 

This work revolves around the concept of ÂWASTE TO VALUEÂ, where a sample meant to be thrown away has been reused for the development of a sensor chip. Using such technological innovation, in future various analytical systems can be developed from trash to be used in industries for point-of-care analysis of other clinically important molecules.