Waterborne illnesses reduce the quality of life of several million people worldwide. As with other developing countries, contaminated drinking water impacts the health of people in both rural and urban Pakistan; in 1998, more than 90% of water sources in rural areas of Punjab province and more than 60% of water sources in Lahore - the largest city in Punjab - were contaminated with bacteria. The first step in addressing drinking water safety is the rapid and efficient detection of the contaminating agent(s). Progress Reports
Efforts in the last year focused on developing effective test strips to rapidly and visually evaluate bacterial drinking water contamination. The team was able to develop strips that can detect as little as 1000 cell/mL. The ultimate goal is to create strips that detect 100 cell/mL. With this in mind, the team has been in the process of developing new nanoparticles to increase sensitivity. Once these improved test strips are available, field tests to analyze the particles in urban and rural locations in Pakistan will be carried out.
Significant investments in technological capability were made. The Pakistani team procured a Zetasizer Nano ZSP (by Malvern) to measure particle size, particle size distribution and zeta potential of nanoparticles. A multilabel plate reader (Perkin Elmer) was also purchased for the measurement of absorbance, fluorescence, and time resolved fluorescence of nanoparticles and fluorescent materials (organic or inorganic). In addition, they purchased a refrigerator and incubators to store the chemicals and samples. A laboratory technician at LUMS is currently being trained to operate both of these new pieces of equipment.
The educational impacts of this project during the last year were noticeable. Dr. Hussain recruited two Ph.D students, a fulltime researcher, and two undergraduate students to work on this project. The doctorate students, Shazia Mumtaz and Zill-e-Huma, are working on the synthesis and functionalization of magnetic iron oxide nanoparticles and their applications for bacterial detection. Ms. Mumtaz spent three months being trained on nanoparticle creation and inkjet printing.
Researcher Ibrahim Javed and two undergraduate students are also working on the synthesis of magnetic nanoparticles of different sizes and growing polymer brushes on their surface to enhance their interaction with bacterial cells and subsequent applications in bacteria detection and multi-drug resistance. In addition the Pakistani group was able to introduce a seminar course related to this project at LUMS. The course will be appropriate for senior undergraduate and graduate students, and at least four lectures on the findings of this project will be delivered to students to discuss the applications of nanoparticles, the biomedical sciences in general and bacterial detection in particular.>
On the U.S. side, six graduate students have been included in the project’s undertakings. Their tasks have involved inkjet printing, microbiology assistance and the development of catalysts including both the iron oxide particles discussed here as well as alternative catalysts for bacterial detection. Dr. Rotello’s team has also instituted weekly subgroup meetings at the university which focus on test strip development. Dr. Rotello, members of his team, and other colleagues also submitted an article on inkjet-printed test strips to the journal ACS Applied Interfaces and Materials.
2015: Research in 2014-2015 was focused on the development of effective test strips that can rapidly detect bacterial contamination in drinking water within minutes based on a visual change in color. Although there were some highly encouraging preliminary results, the teams have encountered challenges to generating a truly reliable and reproducible platform. New methods are now being systematically evaluated and developed to increase sensitivity without compromising the reproducibility of the sensor. The team expects to have a working and reliable prototype in the next annual reporting period.
2016: Research in 2015-2016 was focused on development of effective test strips to rapidly (within minutes) detect bacterial contamination in drinking water based on a visual change in color. We are now systematically evaluating and developing new methods to increase sensitivity without compromising the reproducibility of our sensor. We have achieved excellent sensitivity in solution sensing, and will be applying these systems to paper format in the coming months.
2017: Waterborne illness is a major issue worldwide. The World Health Organization estimates 1.2 billion people worldwide do not have access to safe drinking water, resulting in over 300 million illnesses and the death of an estimated 2 million children per year. Drinking water contamination is an important issue in both rural and urban Pakistan. In 1998, more than 90% of the water sources in rural areas of the Punjab province and more than 60% of the water sources in Lahore had bacterial contamination. The health impact of this contamination is magnified by the prevalence of antibiotic-resistant strains: a 2009 study showed that 400 of 625 drinking water samples from Lahore (64%) contained resistant strains. The first step in addressing drinking water safety is the rapid and efficient detection of contamination. Water quality can vary rapidly; however, with short-term peaks in bacteria levels leading to increased outbreaks of disease, requiring regular monitoring in the field. The widespread nature of drinking water contamination coupled with the need for regular monitoring necessitates robust, reliable and inexpensive bacterial sensing strategies.
In our research, we developed nanoparticle systems engineered to detect bacteria. This system catalyzes the formation of a colored dye in the absence of bacteria. In the presence of bacteria, catalysis is shut down and no color is generated. Over the course of our research, we focused on increasing the sensitivity of this turn-off process, ultimately producing a system capable of detecting 100 bacteria per mL. The iron oxide particles are very inexpensive to produce, providing the required low-cost sensor platform. The current system is solution-based, with planned research focusing on using these nanoparticles in a paper-based diagnostic.
