Monday, October 31, 2016

12:00-12:50 pm, TRC 206

Sheniqua Brown (PhD student with Drs. Rao and Tolosa) 

Optical Biosensors for Detecting Micromolar Glucose & Glutamine in Biomedical & Bioprocess Applications

During prenatal development, a baby’s nutrient supply, through their mother, is a key factor in the regulation of fetal growth.  During birth when the umbilical cord is cut, transplacental glucose is interrupted which can lead to issues in the normal development and survival of the neonates mainly because glucose is their main energy source.   Likewise, when the metabolic balance of a newborn is disrupted by stressors (i.e. diabetes, premature birth, etc…) the likelihood of developing dangerous glucose levels increases.  Current technologies that aid in monitoring glucose levels in neonates are useful; however, all require painful, invasive blood draws that can increase the risk of infection.  For this reason, there is a need for a non-invasive technology that allows glucose levels to be analyzed in neonates while still maintaining the accuracy of the medical field’s established method. My research involves developing a non-invasive monitoring technique that uses a protein based sensor tagged with two fluorescent probes. This optical biosensor is capable of detecting micromolar glucose passively diffusion through human skin. Recent work has looked into the immobilization of the protein for consideration as a sensor rather than the assay setup previously used.  A portable spectrophotometer is being used as a potential point of care technology. The developed biosensor can also be used for glucose monitoring in cell culture. A similar sensor for glutamine detection is also being developed for cell culture applications.

Mehregan Jalalizadeh (PhD student, Ghosh Lab)

Actively shaken in situ passive sampler for measuring porewater concentrations of hydrophobic organic compounds

The freely dissolved concentration of hydrophobic pollutants in sediment porewater is an excellent predictor of sediment toxicity and bioaccumulation in benthic organisms, but extremely difficult to measure due to association with colloids. Passive sampling for the measurement of dissolved concentration in sediment porewater has emerged as a promising approach, but in situ measurements are challenged by slow mass transfer of strongly hydrophobic compounds in sediments and slow approach to equilibrium. We report an engineering innovation of adapting low-cost vibration motors to disrupt the diffusive boundary layer and enhancing the mass transfer of high molecular weight pollutants into passive samplers deployed in sediment. Through laboratory experiments and numerical mass transfer modeling we have demonstrated that the vibrating platform greatly improves the approach to equilibrium and accuracy of porewater measurements for strongly hydrophobic compounds.