Optical Method for Detection and Analysis of Biological Molecules Faculty Mentor Dr. Anastasios Angelopoulos Associate Professor, School of Energy, Environmental, Biological and Medical Engineering Graduate Student Mentor Mr. Srivathsan Ravi Graduate Student in Chemical Engineering 1

INTRODUCTION:  Bradykinin (BK) is a 9-amino acid peptide that causes blood vessels to enlarge  Overactivation of BK causes swelling attacks in patients with Hereditary Angioedema  Studies indicate need for direct monitoring of BK in circulation to optimize drug-based therapy  Direct measurement of BK is challenging due to very low physiological (ppb) concentrations of BK and its rapid breakdown to metabolites.  The aim of this work is to determine whether a catalytic optode using perfluorosulfonic acid (PSA) polymer membranes would selectively respond to the presence of BK at sub-ppb levels 2

 PSA membranes are shown to catalyze reactions between immobilized dye molecules and various toxic reagents  Optical response arises from synthesis of unique products within the membrane  UV-Vis spectroscopy is used to calibrate the optical response of the dyed membrane to these reagents.  Sensing element is produced with optimum selectivity, sensitivity and dynamic response capable of incorporation into a hand-held device employing LED light sources  Sensing approach is previously applied to various reagents of interest (e.g., detection of trimellitic anhydride,acid-base condensation for acetone detection) BACKGROUND: 3 Figure 1. Catalytic optodes after exposure to indicated TMA concentrations

4.  Similar approach is employed to determine if a catalytic optode can be synthesized to selectively respond to the presence of BK at sub-ppb levels in various liquid environments.  Diffusion of high molecular weight polymers into the PSA membrane suggest the possibility of combining the catalytic properties of the membrane to react the resorcinol dye with a suitable pendant group on BK (specifically, a carboxylic acid) to alter the spectral response of the dye.  The proposed sensing reaction is  Preliminary data shows that the optical response from the reaction of BK with resorcinol interferes with the response of the control membrane which contains only resorcinol and is exposed to precisely the same conditions

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6 FUTURE WORK IN SUMMER:  Future work involves producing a sensing element response to BK and undertake a calibration of BK at various concentrations  For this purpose, PSA membranes will be immobilized with the concentrations of resorcinol and BK, which would give optimal response to BK in the visible region  UV/Vis spectrophotometer will be used to analyze the response of the reaction between BK and resorcinol  The key outcome of this effort will be to produce a sensing element with calibrated selectivity, sensitivity, and dynamic response to BK