Abstract: Mercury Sensing with Doped Conjugated Polymer Nanoparticles

Hi Everyone!

My name is Sumaia Tabassum, and I am a rising junior. I am majoring in chemistry and I will be working in Dr. Harbron’s Organic Chemistry lab this summer. Our project has been ongoing for several years through the hands of various student faculty collaborations. They developed fluorescent nanoparticles that could detect mercury in water at concentrations as low as 0.7 parts per billion (ppb).  Created from conjugated polymers, these nanoparticles are small, stably suspended in water, and highly fluorescent in the green-yellow region of the spectrum (Childress and Roberts, 2012).  These nanoparticles can be doped with mercury-responsive dye molecules.  These dyes are non-fluorescent until  they come in contact with mercury, which transforms them into red-fluorescent dyes that quench the fluorescence of the nanoparticles by a mechanism called Fluorescence Resonance Energy.

The ratio of the green nanoparticles to red dyes can be used to study the concentration of mercury in water. Unfortunately, the dyes have some defects. They are impossible to purify completely in lab, and they become fluorescent without an encounter with mercury if they are held in solution in room temperature for an extended period.  Our current system is not stable enough to be tested in biological environments, for which a second-generation system must be created. My research tests whether dye-doped nanoparticle can be created to be stable enough for detecting sub-parts-per-billion levels of mercury in real-world samples such as lake water or fish tissues. I hope this summer is filled with many new discoveries and I am delighted to have this amazing opportunity to share my findings with you!