Development of Optical Biosensing Methods for Detection of Toxins Produced by Algae
A PhD research study by Rukaiah Al-Ammar
Microcystin-LR is a toxin which is released by algae in water and difficult to remove by traditional treatment for drinking water, like adding chlorine and alum to raw water. MC-LR is stable and resistant to chemical hydrolysis or oxidation near neutral pH. It remains potent even after boiling. Coagulation, flocculation, and filtration are frequently used in drinking water treatment. These technologies are effective in removing particulate cyanobacterial cells, but not effective for dissolved toxins like microcystin-LR, reports that chemical treatment and mechanical agitation may cause damage to cyanobacterial cells, and result in an additional release of the toxin. Treatment using chlorination requires high doses and long contact times, and may produce carcinogenic substances such as trihalomethane and other mutagens.
Rukaiah's work focuses on detection of microcystin-LR (MC-LR) in direct immunoassay with specific monoclonal antibody (MC10E7) using optical technique of total internal reflection ellipsometry (TIRE) as well as direct UV-vis spectra measurements. The concentration of MC-LR toxin produced naturally by algae microcystis aeruginosa was evaluated using calibration data obtained for solutions of spiked with known concentrations of commercially available MC-LR. The detection limit for MC-LR between 0.1 and 1ng/ml was achieved using TIRE detection. The role of environmental factors (temperature, pH, nutrition contents, salinity) on the efficiency of production of MC-LR by microcystis aeruginosa was studied.
Purification of solutions contaminated with MC-LR (both commercial and naturally produced) was achieved using MnCO3 microparticles coated with polyelecrolytes and functionalised with MC10E7 antibodies as an absorbent for MC-LR. Also, the concentration of MC-LR in solutions was reduced as a result of direct electrolyses.
Professor Alexei Nabok, was Rukaiah's Director of Studies. He commented
'Dr. Rukaiah Al-Ammar defended recently (December 2014) her PhD thesis entitled “Development of optical bio-sensing methods for detection of toxins produced by algae”. She did very well during 4 years PhD study at MERI combining her study with family duties (bringing up four children, one was born here in Sheffield during her PhD study). Rukaiah produced a good research work in collaboration with BMRC (Prof. T. Smith); she published four journal papers, presented her work on several International conferences, and twice (in 2011 and 2013) was given 3rd prize for her posters at MERI/BMRC research conferences.'