Progress 09/01/20 to 02/23/22
Outputs
Target Audience:Potential customers of our sensors include farmers, food production companies (Grande Cheese), end users or water, water and wastewater utilities, water equipment suppliers, and environmental protection agencies (EPA, DNR) at the municipal, state and federal level. During our Phase II proposal period, we plan to sellour fast, sensitive, selective, and cost-effective handheld devices to to our customers (farmers, food production companies and monitoring agencies). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project allowed training opportunity for our undergarduate intern Alina Urbansky. She gained training on water quality testing with our sensor which will be important in her career as an environmental engineer. She also gained vital research experience about pathogens and micro-organism and co-authored a presentation in Electrochemical Society (ECS) meeting on May 2021. Nanoaffix Employees also gained a lot of professional development opportunities during the course of this project. We presented our work ECSmeeting on May 2021. The presentation reached an audience of 5000+ viewers and archived in the meeting abstracts. On top of that the project also enabled us to explore Water Environment Federation Technical Expo (WEFTEC 2021) in Illinois on October 2021. WEFTEC provided us a glimpse of the water quality monitoring market and gave us an idea of our potential collaborators (and competitors). How have the results been disseminated to communities of interest?During the Phase I of our project, we have finished optimizing as aspects of our handheld device of E. coli monitoring. We presented our technology to the broader scientific community during the ECSmeeting on May 2021. During the initial Phase II period, we will do beta-testing for ourproduct with our potential customers (farmers, food production companies and monitoring agencies). By the end of Phase II, we hope to have a working handheld device ready for sale. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1.Improve the sensor sensitivity and stability of E. coli sensor chip An important feature in any sensor is the sensitivity. Increased sensitivity enables the detection of toxic pathogens at lower concentrations. The proposed sensing platform combines the outstanding properties of reduced graphene oxide (rGO) with sensing performance enhancement through the addition antibody and nanoparticles. The first research objective in this project is to increase sensitivity by optimizing the antibody concentration. Our results have suggested that having an optimized concentration of antibody and reactive ester groups improves sensitivity. After we have optimized the type of antibody and the concentration of antibody our sensitivity improves about 2-fold. Furthermore, when we optimize the reactive ester group our sensitivity improves around 3-fold. The stability and lifetime of the sensor are also critical for the commercialization of the E. coli sensor and needs to be determined prior to commercialization. Additionally, we tested for the optimum condition the sensors have to be stored. Results suggest that, storing them at 4°C gives us the best sensitivity performance. Furthermore, we have tested the sensitivity of our sensor devices over a period of 1 month. The results suggest that, the sensitivity of the sensors is stable for one week and their performance diminish significantly at the end of one month. With more optimized surface coating we make the sensors last for as long as 6 months. During our proposed Phase II period, we will continue to work on optimizing various parameters of sensor surface to make their shelf-life at least 6 months. 2. Investigate the specificity of the E. coli handheld device The specificity of the E. coli handheld device is critical for its application, and false positive signals from the meter will impair its commercialization potential. The sensor uses anti- E. coli which makes it highly specific to target i.e., E. coli. In our preliminary work we used generic E. coli antibody. Our results suggest that the sensors respond to E. coli O157:H7. However, since the antibody responds to all strains of E. coli, it also responded to other strains of E. coli like E. coli O111:B1. Additionally, this generic antibody sensors responded to other organisms like Salmonella (S. typhimurium) and Pseudomonas (P. aeruginosa). These results suggest a need for more selective sensors that will respond to E. coli O157:H7. To solve this issue, we experimented with specific antibody that will only respond to E. coli O157:H7. This is possible due to the fact that the sensor chip is a platform-based technology, and different antibodies can be easily linked to the graphene with Au NPs and chemical linkers. Our results suggest that the sensitivity improved with the use of a anti E. coli O157:H7. After making these modifications, the specificity data improves greatly. Our data shows that, once the specific antibody is used the sensors respond to E. coli O157:H7 only and is not responsive towards other bacteria (Salmonella and Pseudomonas) or other strains of E. coli (E. coli O111:B1). 3. Prototype a handheld device with improved reproducibility and calibration We have produced a prototype handheld device for E. coli detection in water. The prototype handheld device contains sensor chips in a sensor housing, a meter for current measurement and a phone with an app developed at NanoAffix. The meter was designed under the principle of being simplistic in nature, yet powerful enough to offer desired functions. The key hardware components of the meter include a potentiostat that can be connected to any phone or PC via USB or Bluetooth. The sensor housing is used to set the sensor chip securely, ensure appropriate amount of water sample during a test, and provide easy yet reliable connection/disconnection between the sensor and the meter. We have designed a test cell using 3D printing for rapid prototyping. The magnetic rod holds the sensors secure in place during the testing. This improves the stability of device with minimum external influence. This also increases the lifetime of the device since the housing is less prone to wear and tear than mechanical fittings. The meter communicates with the phone app via Bluetooth. The app communicates between the channels of the potentiostat, calculates resistance, determines the concentration of E. coli from the calibration model, sends the results to app and displays the concentration of E. coli. Our preliminary results have shown that, the app and the calibration algorithm give the E. coli concentration. For the testing, we have tested lab-prepared sample that had 100 cfu/mL E. coli solution and our device showed the value between 29-40 cfu/mL (# of trials =3). Please note that, we used heat-killed bacteria for sample preparation in our lab. We have enabled the phone app to store testing results, which will provide users with the convenience of data storage, instead of manually recording testing results. We have written the code in the app so that the meter runs and make it store all the E. coli testing data points, each of which will have information including sample number, date and time, the GPS data and E. coli concentration. The user can also add additional comments on the test if needed directly in the app. The user can retrieve the saved data from the meter when needed in the mobile app. 4. Test real water samples against the gold standard and seek EPA and FDA approval The NAFX E. coli handheld device is made for rapid detection in various fresh water sources, including surface water, groundwater, and process water. The major challenge in this task is the sensor selectivity for real water samples, since various constituents are present in water, including microorganisms, inorganic chemicals, organic chemicals, and disinfectants and disinfection byproducts (tap water). All these components may attach to the sensor surface during the test; however, because there are no specific links for the non-specific components, their binding with the sensor is anticipated to be very weak. We believe these additional components will not impact the function of the antibody on the sensor or the specific binding between the antibody and E. coli cells, which have been confirmed in this task. For the testing, we have tested lab-prepared sample that had 100 cfu/mL E. coli solution and our device showed the value between 29-40 cfu/mL (# of trials =3). Please note that, we used heat-killed bacteria for sample preparation in our lab. Our handheld device showed similar results when we tried to test with live E. coli O157:H7 in the UWM facility with our collaborators. The accuracy will improve when we optimize and implement a flow-cell that will erase further uncertainty in measurement. Please note that, one of the challenges we face in measuring of E. coli is the uncertainty of the number of bacteria in the solution. Since one 1µL of solution can contain any range of E. coli bacteria, it is often hard to quantify the amount. To solve this problem, we plan to implement a flow-cell type mechanism, where we will measure the amount of solution in 100mL of running water. We will optimize our current handheld meter to acceptable accuracy levels during our Phase II period. We will then compare the performance of our method will be compared with the EPA approved E. coli testing methods, such as Method 1603. We will also follow FDA's "Equivalent Testing Methodology for Agricultural Water" to validate our method in terms of accuracy, precision, and sensitivity in quantifying generic E. coli in agricultural water with the criteria described in § 112.44(a) or § 112.44(b).
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Md Imran Imran Hossain et al 2021 Meet. Abstr. MA2021-01 1530
|
Progress 09/01/20 to 08/31/21
Outputs
Target Audience:Potential customers of our sensors include farmers, food production companies (Grande Cheese), end users or water, water and wastewater utilities, water equipment suppliers, and environmental protection agencies (EPA, DNR)at the municipal, state and federal level. Before our final reporting period, we plan to invite them to test our handheld device in their water samples.We hope our fast, sensitive, selective, and cost-effective method or sensing platforms will be very beneficial for themto detectE. coli in water. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project allowed training opportunity for our undergarduate intern Alina Urbansky. She gained training on water quality testing with our sensor which will be important in her career as a environmental engineer. She also gained vital research experience about pathogens and micro-organism and co-authored a presentation in electrochemistry society (ECS) meeting on May 2021. Nanoaffix Employees also gained a lot of professional development opportunities during the course of this project. We presented our work inelectrochemistry society(ECS) meeting on May 2021. The presentation reached an audience of 5000+ viewers and archived in the meeting abstracts. On top of that the project also enabled us to explore Water Environment Federation Technical Expo (WEFTEC 2021) in Illinois on October 2021. WEFTEC provided us a glimpse of the water quality monitoring market and gave us an idea of our potential collaborators (and competitors). How have the results been disseminated to communities of interest?During the Phase I of our project, we have finished optimizing severalaspects of our handheld device of E. coli monitoring. We presented our technology to the broader scientific community during the electrochemistry society (ECS) meeting on May 2021. In the remaining time period for the project,we will test this product with our potential customers (farmers, food production companies and monitoring agencies). Those results will help us determine the accuracy of device and add/drop features according to customer feedback. What do you plan to do during the next reporting period to accomplish the goals?In the remaining time period, we will test this product with our potential customers (farmers, food production companies and monitoring agencies). On top of that, we want to keep doing research on one important aspect of E. coli sensors: sample pre-concentration. We plan to design a flow cell whereby we can have a continous flow of 100 mL water and detect E. coli concentration in the water. If we are successful in designing our flow cell laborious pre-concentration and filtration step will not be required.
Impacts
What was accomplished under these goals?
1. Improve the sensor sensitivity and stability of E. coli sensor chip An important feature in any sensor is the sensitivity. Increased sensitivity enables the detection of toxic pathogens at lower concentrations. The proposed sensing platform combines the outstanding properties of reduced graphene oxide (rGO) with sensing performance enhancement through the addition antibody and nanoparticles. The first research objective in this project is to increase sensitivity by optimizing the antibody concentration. Preliminary results have suggested that having an optimized concentration of antibody and reactive ester groups improves sensitivity. We detected E. coli concentration as low as 100 cfu/mL. The stability and lifetime of the sensor are also critical for the commercialization of the E. coli sensor and needs to be determined prior to commercialization. Additionally, we tested for the optimum condition the sensors have to be stored. Results suggest that, storing them at 4°Cgives us the best sensitivity performance. Furthermore, we have tested the sensitivity of our sensor devices over a period of 1 month. The results suggest that, the sensitivity of the sensors is stable for one week and their performance diminish significantly at the end of one month. 2. Investigate the specificity of the E. coli handheld device The specificity of the E. coli handheld device is critical for its application, and false positive signals from the meter will impair its commercialization potential. The sensor uses anti- E. coli which makes it highly specific to target i.e., E. coli. In our preliminary work we used generic E. coli antibody. Our results suggest that the sensors respond to E. coli O157:H7. However, since the antibody responds to all strains of E. coli, it will also respond to other strains of E. coli like E. coli O111:B1. Additionally, this generic antibody sensors responded to other organisms like Salmonella (S. typhimurium) and Pseudomonas (P. aeruginosa). These results suggest a need for more selective sensors that will respond to E. coli O157:H7. To solve this issue, we experimented with specific antibody that will only respond to only E. coli O157:H7. This is possible due to the fact that the sensor chip is a platform-based technology, and different antibodies can be easily linked to the graphene with Au NPs and chemical linkers. Our results suggest that the sensitivity improved with the use of a specific antibody. Moreover, the specificity data is also promising. Our data shows that, once the specific antibody (that responds to E. coli O157:H7 only)is used, the sensors respond to E. coli O157:H7 only and is not responsive towards other bacteria (or other strains of E. coli) 3. Prototype a handheld device with improved reproducibility and calibration We have produced a prototype for handheld device for E. coli detection in water. The prototype handheld device contains sensor chips in a sensor housing, a meter for current measurement and a phone with an app developed at NanoAffix. The meter was designed under the principle of being simplistic in nature, yet powerful enough to offer desired functions. The key hardware components of the meter include a potentiostat that can be connected to any phone or PC via USB or Bluetooth. The sensor housing is used to set the sensor chip securely, ensure appropriate amount of water sample during a test, and provide easy yet reliable connection/disconnection between the sensor and the meter. We have designed a test cell using 3D printing for rapid prototyping. The magnetic rod holds the sensors secure in place during the testing. This improves the stability of device with minimum external influence. This also increases the lifetime of the device since the housing is less prone to wear and tear than mechanical fittings. The meter communicates with the phone app via Bluetooth. The app communicates between the channels of the potentiostat, calculates resistance, determines the concentration of E. coli from the calibration model, sends the results to app and displays the concentration of E. coli. Our preliminary results have shown that, the app and the calibration algorithm give the E. coli concentration We have enabled the phone app to store testing results, which will provide users with the convenience of data storage, instead of manually recording testing results. We have written the code in the app so that the meter runs and make it store all the E. coli testing data points, each of which will have information including sample number, date and time, the GPS data and E. coli concentration. The user will also be able to add additional comments on the test if needed directly in the app. The user will be able to retrieve the saved data from the meter when needed in the mobile app. 4. Test real water samples against the gold standard and seek EPA and FDA approval The NAFX E. coli handheld device is made for rapid detection in various fresh water sources, including surface water, groundwater, and process water. The major challenge in this task is the sensor selectivity for real water samples, since various constituents are present in water, including microorganisms, inorganic chemicals, organic chemicals, and disinfectants and disinfection byproducts (tap water). All these components may attach to the sensor surface during the test; however, because there are no specific links for the non-specific components, their binding with the sensor is anticipated to be very weak. We believe these additional components will not impact the function of the antibody on the sensor or the specific binding between the antibody and E. coli cells, which have been confirmed in this task. During the remaining time period, we will test out our handheld devices with our potential customers like Grande cheese, WI-DNR and report on the accuracy of our devices.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Md Imran Imran Hossain et al 2021 Meet. Abstr. MA2021-01 1530
|