Executive Summary : | Antibiotics and their residues are emerging active pharmaceutical contaminants of water and food causing widespread toxicity to life. Nitrofurans and amphenicols are two such inexpensive, broad spectrum bactericidal antibiotics which are frequently used in aquaculture and livestock industries as preventive and therapeutic drugs. Nitrofurantoin (NTF) and chloramphenicol (CAP) are two of the most commonly used antibiotics in the classes: nitrofurans and amphenicols, respectively. Chronic ingestion of these drugs, and their metabolites is known to cause moderate to severe pathogenesis in humans. The food safety and standards authority of India (FSSAI), proscribes the use of these drugs in the food industry which includes meat products, poultry, eggs, seafood such as prawns, shrimps and fishes. The FSSAI has defined the maximum residual limit of 1 µg/kg and 0.3 µg/kg nitrofurans and chloramphenicol in food respectively. The gold standard technique for detection of these molecules are LC-MS based approaches which are laboratory based, cost and labor intensive. Hence, despite regulatory policies, due to lack of point of use assessment technologies, indiscriminate use of these antibiotics undermining human health continues. This also accounts to rejection of seafood exports causing significant losses as well as disrepute to India. There is thus a need to develop rapid, sensitive and reliable sensors for quantitative detection of NTF and CAP in animal and aquatic feed, as well as produce. Researchers propose to develop disposable, electrochemical sensors for voltammetric detection of NTF and CAP. Screen/inkjet printed carbon-based electrodes will be fabricated on inexpensive substrates, such as, cellulose/polymer. These would be modified with metal-organic framework (MOF)/metal nanoparticles for enhanced sensitivity. Biorecognition elements such as antibodies and aptamers immobilized on the working electrode will be used for specific detection of NTF and CAP. Molecular imprinted polymers shall also be experimented as a secondary choice of biorecognition element. The materials and methods of sensor design shall be optimized to achieve sensitivity, range and LoD of relevance in practical use case scenarios in India. Further, the sensor shall be calibrated for quantitative assessment of these compounds and validated with limited real samples characterized to contain these compounds by standard analytical practices involving LC-MS. In a parallel approach, we propose to develop molecularly imprinted plastic optical fibers for LSPR based detection of the said molecules. Preliminary experiments done on these lines exhibit promising prospects (in OTD file). Antibody encapsulated MOF on gold coated plastic optical shall also be deployed for SPR measurements. The final aim is the proposal is design of portable, robust, direct readout instrumentation system for the better of the two approaches defined earlier with minimal or no sample pre-processing requirements. |