SBIR-STTR Award

There is an increasing public concern about monitoring water quality in the entire drinking water supply system, especially at the point of use, spurred by recent water catastrophes, such as the one in Flint, Michigan that has caused severe health issues for thousands of children due to the unsafe level of lead in contaminated drinking water. Current quantitative detection methods for aqueous lead are often laboratory-based and are too expensive and time-consuming, unsuitable for end water users to perform fast and onsite detection. This project aims to investigate the feasibility of a handheld device for real-time, onsite detection of toxic lead in tap water. The device integrates a novel micro-sized sensor chip built upon a graphene-gold nanoparticle sensing platform with a portable digital signal meter for direct readout of testing results. This project intends to address the need for quantitative, real-time, in situ detection of total dissolved lead ions in tap water by developing a sensitive, specific, fast, portable, and cost-effective prototype handheld device that can be self-administered without any special training. Major innovations of the project lie in the use of an aqueous sensing platform with superior sensing performance (i.e., high sensitivity, excellent selectivity, and fast response under laboratory environment and in field settings) and the combination of the sensor with a digital meter for direct display of testing results in tens of seconds. The sensing platform consists of a multifunctional hybrid nanostructure (i.e., graphene as the sensing signal transduction channel and the support for gold nanoparticles functionalized with chemical probes), which is capable of differentiating lead ions from other aqueous ions (e.g., calcium and magnesium) through specific coupling events between the lead ion and the specially chosen chemical probe (i.e., glutathione) on the gold nanoparticle surface. Specific research aims of the project are to: (1) Determine the influence of pH value on the sensor performance so that sensing results can be interpreted properly; (2) Develop a model to estimate the total dissolved lead based on the measurement of free lead ion concentration in water and implement this model in the handheld device for reporting total dissolved lead concentration in water; (3) Study how potential interfering species in tap water (e.g., disinfection by-products) affect the sensing behavior of the handheld device and to identify possible strategies to minimize the undesirable interference. The technical and commercial feasibility of the handheld device and associated technology will be determined for future development and commercialization. The proposed activities will improve the sensing reliability and device integrity, maximizing the commercialization opportunities of the device. The availability of the device contributes to safeguarding the public drinking water safety, as this innovative sensing technology permits fast, onsite test of lead ions in water supply systems, particularly at the point of use. The framework of the device is also expandable with the potential to serve as the basis to build a sensing network for real-time water quality monitoring of the entire drinking water system, enhancing the public drinking water safety.

Public Health Relevance Statement:
PROJECT NARRATIVE The project aims to develop a handheld device for real-time, onsite detection of toxic lead in tap water. Lead can accumulate in the human body's soft tissue and bones, cause poisoning, and disrupt body processes, and is toxic to many internal organs. The primary source for lead in most drinking water supply stems from the leaching of lead from lead-bearing pipes in a water distribution system or the household plumbing/fixtures. Catalyzed by the unfortunate Flint Water Crisis, there is increasing public demand on water quality monitoring in the entire drinking water supply system, from the water treatment plant to the tap at the point of use. Current quantitative detection methods for aqueous lead are mostly laboratory-based and are too expensive and time-consuming, unsuitable for end water users to perform fast and onsite detection. This project will contribute to enhancing the public health by providing water users with a handheld device for real-time, onsite monitoring of lead in tap water.

Project Terms:
Address; Affect; Aging; aqueous; Bacteria; base; Behavior; Biological; bone; Brain; Calcium; Cations; Chemicals; Child; commercialization; Communication; Complex; contaminated drinking water; cost; cost effective; Coupling; Data; Detection; Development; Devices; digital; Disinfection; drinking water; Ensure; Environment; Event; Future; Glutathione; Gold; graphene; handheld equipment; Health; Health Benefit; Heart; Heavy Metals; Household; Human body; Hybrids; Immobilization; improved; In Situ; innovation; Intake; Ions; Kidney; Label; Laboratories; Lead; lead concentration; lead contamination; lead exposure; lead ion; Lead levels; Lead Poisoning; Legal patent; Magnesium; Measurement; Mercury; meter; Methods; Michigan; Modeling; Monitor; nanoparticle; nanosensors; Nanostructures; novel; operation; Organ; Oxides; Performance; Phase; Plants; Plumbing; Poisoning; portability; Preparation; Privatization; Process; Proteins; prototype; public drinking; Public Health; Reporting; Research; response; Risk; Safety; Sampling; Schools; Self-Administered; Sensitivity and Specificity; sensor; Signal Transduction; Small Business Technology Transfer Research; soft tissue; Source; stem; Structure; Surface; System; Technology; Test Result; Testing; Time; Training; United States Environmental Protection Agency; Water; water quality; Water Supply; water testing; water treatment; Wireless Technology; Wisconsin

Detrimental health impacts of lead are largely attributed to long-term exposures to undetected lead, which are particularly troublesome and problematic because of the neurological damage to children, a situation that should not be tolerated by an advanced society like the U.S. The Flint Water Crisis and many other water catastrophes could have been avoided if early warning can be made possible through timely detection of lead in drinking water at the point of use. Our extensive customer interviews unambiguously suggest that current options for lead detection are unsatisfactory for on-site testing, as they represent two extremes: one being accurate but expensive, slow, and hard to use; and the other being low-cost, fast, and easy to use but inaccurate. NanoAffix Science LLC (NAFX) proposes to address the above unmet need and niche market product gap by empowering water users (particularly those in economically disadvantaged communities) and water service providers with a low-cost, easy-to-use, and accurate handheld tester for rapid detection of total lead in the tap water, right from the kitchen sink. The handheld lead tester combines a novel proprietary micro-sized sensor chip embedded in a proprietary test cell with a portable digital meter for direct readout of testing results. The Phase I project has successfully established the feasibility for detection of soluble lead in the tap water using an earlier version of the prototype handheld tester. The Phase II project will continue to develop the handheld tester toward total lead detection, better device uniformity, pilot scale-up manufacturing, and accurate calibration. At the end of the Phase II project, NAFX plans to produce 20 beta units of the handheld lead tester meeting all performance specifications for field validation by 10 initial customers (e.g., schools/daycares, end water users, and well water drillers). Major innovations of the proposed approach include accurate prediction of the particulate lead through partial digestion based on lead digestion kinetics, and strategic and synergistic improvement of the ultimate sensor prediction accuracy by (1) improving the physical sensor device uniformity (both intra-wafer and inter-wafer) through innovative device configuration and rigorous quality control; and (2) improving the calibration accuracy through innovative theoretical equilibrium chemistry modeling and machine learning data analytics. The NAFX handheld lead tester is the first of its kind to (1) offer all three features sought by customers: accurate, cheap, and fast; and (2) to simultaneously report all three types of lead: total lead (indicative of overall toxicity), soluble lead (indicative of slow leaching of lead), and particulate lead (indicative of sporadic flaking of lead), which thus can not only alert customers to the lead hazard in their drinking water but also enable customers to identify possible causes and most effective solutions to mitigate the lead contamination. Therefore, the project will result in not only considerable economic impact but also immense societal impact. The regular use of NAFX handheld tester - even if intermittently - will virtually eliminate the chance of chronic exposure to undetected lead, thereby accruing significant and predictable public health impact, especially in locations with the highest risk.

Public Health Relevance Statement:
PROJECT NARRATIVE The NanoAffix Phase II project aims to continue the development of a handheld lead tester for accurate and low- cost onsite detection of total lead in tap water by untrained users, based on the success of the Phase I project. The project will contribute to enhancing the public health by offering an accessible tool for quantitative monitoring of all three types of lead: total lead (indicative of overall toxicity), soluble lead (indicative of slow leaching of lead), and particulate lead (indicative of sporadic flaking of lead) in tap water. The regular use of NanoAffix handheld tester - even if intermittently - will virtually eliminate the chance of chronic exposure to undetected lead, thereby accruing significant and predictable public health impact, especially in locations with the highest risk.

NIH Spending Category:
Bioengineering; Lead Poisoning; Nanotechnology

Project Terms:
Address; Algorithms; aqueous; base; Calibration; Cations; Cells; Chemistry; Child; Chronic; Communication; Communities; Complex; Contracts; cost; Data; Data Analytics; Detection; Development; Devices; Digestion; digital; Disinfection; drinking water; economic impact; Economically Deprived Population; empowered; Equilibrium; Equipment; Exposure to; Goals; Gold; graphene; hazard; Health; high risk; improved; innovation; International; Interview; Kinetics; Laboratories; Lead; lead concentration; lead contamination; Lead Poisoning; Location; Machine Learning; manufacturing scale-up; Measurement; meetings; meter; Michigan; Modeling; Monitor; nanosensors; Nervous System Trauma; novel; operation; Paper; Particulate; Performance; Phase; portability; Procedures; Process; prototype; Public Health; Quality Control; rapid detection; real time monitoring; Reporting; Research; response; sample collection; Schools; Science; sensor; service providers; Site; Societies; Specialist; success; System; Test Result; Testing; Time; tool; Toxic effect; Training; Uncertainty; Validation; Variant; virtual; Water; water quality; Water Supply; well water; Wireless Technology