Aptamer-Molecular Imprinted Polymer Hybrid Biosensors for Pathogen Detection in Water

Abstract

Waterborne pathogens and the diseases they cause have become a global problem. As these pathogens cause various diseases and deaths, countries allocate very high budgets for their prevention and treatment. Although bacteria, viruses and protozoa are the main waterborne pathogens, bacteria are the main cause of disease and outbreaks. Early diagnosis of infections and diseases caused by bacteria ensures that the right treatment methods are applied in a timely and effective manner. This early detection can only be possible by detecting the bacteria causing the disease accurately and in a short period of time. Various methods have been developed for the detection of bacteria to date. Most of these methods require sample preparation, trained personnel, costly reagents, and 2-4 days for identification. However, great progress has been made in this field with the use of biosensors.
The inherent properties of natural receptors used in biosensors negatively affect both the performance and cost of the sensor. The development of biosensors that will eliminate the disadvantages of natural bioreceptors and that allow the detection of multiple bacteria at the same time need to be low cost and have a fast response to bacterial detection.
Considering the need for fast, inexpensive, and sensitive biosensors for detecting multiple bacteria, this thesis presents electrochemical biosensors consisting of aptamers and molecularly imprinted polymers (Apta-MIP) as biorecognition elements that can detect E. coli DH5a and S. aureus both separately and in multiplexed formats in buffer solution (PBS), deionized water, and tap water. For E. coli DH5a Apta-MIP biosensor, detection limit values in PBS, DI water and tap water were found to be 2, 3, and 3.5 CFU/mL. For S. aureus Apta-MIP biosensor, these values were 4, 5, and 8 CFU/mL, respectively. The multiplexed detection of E. coli DH5a and S. aureus was successfully achieved with the fabricated biosensors. In addition to the Apta-MIP biosensors, aptamer-based and molecularly imprinted polymer-based biosensors were developed, and their E. coli DH5a and S. aureus detection performances were compared with those of the Apta-MIP electrochemical biosensors. It was determined that Apta-MIP sensors detected both bacteria more sensitively than the other biosensors. This study is one of the first examples of Apta-MIP-based electrochemical sensors produced for the multiplexed detection of bacteria in water samples.

Date of Award	25 Jun 2025
Original language	English
Awarding Institution	University of Bath
Sponsors	Ministry of National Education of the Republic of Turkey
Supervisor	Pedro Estrela (Supervisor), Hannah Leese (Supervisor) & Maisem Laabei (Supervisor)