Innovative low-cost optical sensor platform for water quality monitoring

水是生命所必需的。在发达国家，获得安全饮用水可能是常态，但在印度等发展中国家，20亿人获得清洁水的机会有限，根据世卫组织的数据，与水相关的疾病的死亡率每年超过500万人。来自地质来源的废水含有砷、氟等污染物或工业、农业农场排放的污染物，生活垃圾含有制药、重金属、农药、化肥、有机废物和排入江湖的粪便。水源性疾病是由致病微生物引起的，这些微生物大多在受污染的淡水中传播，并因洗澡、洗涤、饮用和准备食物而引起。细菌病原体导致严重腹泻，导致数百万本可避免的死亡，给儿童带来更多痛苦。重金属等工业废物对海洋生物是有毒的，对食用导致出生缺陷和癌症的人来说也是有毒的。许多工业废物的影响可能非常缓慢，往往发现得很晚。废弃的有机物、化肥和营养物质会耗尽水中的氧气，导致鱼类和其他水生生物窒息，最终导致人类食用这些受感染的鱼类。City拥有制造FBG和LPG的优良设施，与IISC的专业知识相辅相成。可以在同一根光纤上制作多个级联的光栅，同时检测多个物种，每个光栅可以制作成不同的选择性，具有不同的布拉格波长用于多路复用。先进的微纤维、微结和微球也可以功能化，以实现更紧凑的光学传感器。另一方面，硅纳米光子学是一个令人兴奋的新兴研究和创新领域，它利用了高度成熟的半导体行业开发的成熟的CMOS技术。奇特的缝隙波导将光限制在低折射率区域，可以很容易地将其功能化，以实现更紧凑的光学传感器，通常只有几微米长。半径小于5微米的高灵敏度硅环谐振器可以检测10E-5的折射率变化，直径2微米的微谐振器支持回声廊模式，能够检测单个分子。这样的微型传感器可以大规模生产，成本大大降低，数百个传感器放在一个毫米见方的晶片中，然后通过一条500 nm的纳米线光学总线进行多路复用和激励，以实现快速的多参数传感。IISC在功能和生物传感方面拥有专业知识，补充了城市在物理和化学感官方面的专业知识。目前覆盖整个印度的水质监测系统，从大都市到小城镇和偏远村庄，质量各不相同。对于界定各种主要污染物的安全限度，缺乏标准化的标准。一些污染物的影响可能非常缓慢，例如重金属的影响，在低污染水平下甚至更难识别，直到人们长期遭受痛苦。解决这一问题的一个方法是改进对快速作用的生物病原体和缓慢作用的化学污染物的监测系统，实现这一点的方法之一是开发方法，快速、现场、准确和连续地监测水质，并在能够从许多可以避免的重大疾病的爆发中识别出任何潜在的水质控制故障。本研究计划的目的是开发经济、紧凑的多通道光学传感器，用于创新和经济高效地开发多种物种，快速、可靠和选择性地检测蛋白质、肽、细胞因子、从细菌和病毒病原体和化学残留物，用于现场和实时饮用、通用和废水监测，可部署到大城市到小农村社区。

Water is essential to life. Access to safe drinking water may be norm in developed countries, but two billion people in developing countries, like India have limited access to clean water and according to the WHO, mortality of water associated diseases exceeds 5 million people per year. Waste water from geological sources contains pollutants like arsenic and fluorides or discharge from industries, agricultural farms, and household wastes contain pharmaceutical, heavy metals, pesticides, fertilisers, organic waste, and faeces discharged to rivers and lakes. Waterborne diseases are caused by pathogenic microorganisms that mostly are transmitted in contaminated fresh water and results from bathing, washing, drinking and in the preparation of food. Bacterial pathogens, cause major diarrhoea, resulting in millions of avoidable deaths, with more suffering of children. Industrial wastes such as heavy metals are toxic to marine life and subsequently to humans who eat those causing birth defects and cancers. Effect of many industrial wastes can be very slow, often identified very late. Waste organic matter, fertilisers, and nutrients deplete oxygen from water and cause suffocation to fish and other aquatic organisms and ultimately human consuming these infected fish. CITY has excellent facilities for fabricating FBG and LPG, complements IISc expertise. Several concatenated gratings can be fabricated on the same optical fibres to detect several species simultaneously and each grating can be prepared for different selectivity with different Bragg wavelengths for multiplexing. Advanced micro-fibres, micro-knots and micro-spheres can also be functionalised for more compact optical sensors. On the other hand, silicon nanophotonics is an exciting emerging area of research and innovation, which exploits the well developed CMOS technology developed by highly matured semiconductor industries. Exotic slot waveguide, where light is confined in a low-index region, can easily be functionalised for much more compact optical sensors, often just several micron long. Highly sensitive silicon ring resonator less than 5 micron in radius which can detect 10E-5 refractive index change and 2 micron diameter micro-resonators supporting whispering gallery modes are capable of detecting a single molecule. Such tiny sensors can be mass manufactured at vastly reduced cost, hundreds of them in a mm-square wafer, and then multiplexed and excited by a single 500 nm nanowire optical bus for rapid multi-parameters sensing. IISc has expertise in functionalisation and bio-sensing complements CITY expertise in physical and chemical sensing.The present water quality monitoring systems over the whole India, from large metropolis to small towns and remote villages are of diverse quality. There is a lack of standardised criteria for defining the safe limits of various key pollutants. Effect of some pollutants can be very slow, such as that of heavy metals, and this can be even more difficult to identify at a low level of contaminations until prolonged suffering by people. A solution to this problem is to improve the surveillance systems, both for fast acting bio-pathogens and slow-acting chemical pollutants and one way to achieve this is to develop methods to rapidly, in-situ, accurate and continuous monitoring of water quality and identify any potential breakdown in quality control well before it can be identified from the outbreak of any major diseases with many avoidable sufferings.The objective of this research proposal is to develop frugal, compact multi-channel optical sensors for innovative and cost-effective development of multi species rapidly, reliably and selectively to detect protein, peptides, cytokine, from bacterial and viral pathogens and chemical residues for in-situ and real-time drinking, general use and waste water monitoring, which can be deployable to large metropolis to small rural community.