Innovative low-cost optical sensor platform for water quality monitoring

水是生命所必需的。获得安全饮用水在发达国家可能是常态，但在发展中国家，如印度，有20亿人获得清洁水的机会有限，根据世界卫生组织的数据，每年与水有关的疾病死亡人数超过500万人。来自地质来源的废水含有砷和氟化物等污染物，或来自工业、农业农场的排放物，以及含有药物、重金属、农药、化肥、有机废物和粪便的家庭废物排放到河流和湖泊中。水传播疾病是由病原微生物引起的，这些病原微生物大多在受污染的淡水中传播，并在洗澡、洗涤、饮用和准备食物时产生。细菌性病原体引起严重腹泻，导致数百万本可避免的死亡，儿童遭受更多痛苦。重金属等工业废物对海洋生物有毒，随后对食用这些废物的人类有毒，导致出生缺陷和癌症。许多工业废物的影响可以很慢，往往很晚才发现。废弃的有机物、肥料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的优秀设施，补充了IISc的专业知识。可以在相同的光纤上制造多个级联光栅以同时检测多个物种，并且每个光栅可以针对不同的选择性与不同的布拉格波长进行制备以用于复用。先进的微纤维、微结和微球也可以用于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工业开发的成熟CMOS技术。光被限制在低折射率区域的奇特缝隙波导可以很容易地被功能化，用于更紧凑的光学传感器，通常只有几微米长。半径小于5微米的高灵敏硅环形谐振器（其可以检测10 E-5折射率变化）和支持回音壁模式的2微米直径微谐振器能够检测单个分子。这样的微型传感器可以以大大降低的成本大规模制造，在一个平方毫米的晶片上有数百个传感器，然后通过单个500 nm纳米线光学总线进行多路复用和激发，以实现快速多参数传感。IISc拥有功能化和生物传感方面的专业知识，补充了CITY在物理和化学传感方面的专业知识。目前，从大型大都会到小城镇和偏远村庄，整个印度的水质监测系统质量各异。目前缺乏界定各种主要污染物安全限值的标准化标准。一些污染物的影响可能非常缓慢，例如重金属，在低污染水平下甚至更难识别，直到人们长期遭受痛苦。解决这个问题的一个办法是改进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，实现这一点的一种方法是开发快速、原位、准确和持续的水质监测，并确定任何潜在的质量控制故障之前，可以确定任何重大疾病的爆发，许多可以避免的痛苦。这项研究的目的本发明提出了一种用于快速、可靠和选择性地对多物种进行创新和成本有效的开发的简单、紧凑的多通道光学传感器，以检测来自细菌和病毒病原体的蛋白质、肽、细胞因子和化学残留物，用于原位和实时饮用、一般用途和废水监测，其可以部署到大大都会到小的农村社区。

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.