Presentation Title

Simultaneous Detection and Decontamination of Organophosphates Using Mesoporous Silica Nanoparticles (MSNs)

Presenter's Name(s)

Michelle E. DiPintoFollow

Abstract

Based on their continuous presence and threat in the environment, a highly specific visual detection system for organophosphorus compounds is needed. For this purpose, we have been working to develop a molecular trigger system incorporating an enzyme-inhibitor release process. Mesoporous silica nanoparticles (MSNs) have valuable physical properties, such as a synthetically controllable pore diameter, a large surface area (300-1600 m2/g), and large pore volumes (> 1.0 cc/g) that are vital to this specific application. In addition, MSNs also boast chemical inertness, stability at a variety of temperatures, and can be easily functionalized with a variety of reactive groups. In the studies reported here, luciferin was loaded into the pores, which were then capped by tethering organophosphorus hydrolase (OPH) to diethyl 4-aminobenzyl phosphate (DEABP), a competitive inhibitor that was covalently bound to the external surface of the MSNs. OPH has the ability to hydrolyze a large range of organophosphate compounds, rendering them non-toxic. Luciferin is a bioluminescent molecule that can also be viewed under a UV light when luciferase, O2, Mg2+, and ATP are present. Upon addition of paraoxon (an organophosphorus compound) to an aqueous suspension of MSNs, the OPH detaches from the competitive inhibitor (DEABP), releasing the luciferin, which in turn can be visually detected using UV light and also more quantitatively with fluorescence spectroscopy.

Primary Faculty Mentor Name

Chris Landry

Status

Graduate

Student College

College of Arts and Sciences

Program/Major

Chemistry

Primary Research Category

Engineering & Physical Sciences

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Simultaneous Detection and Decontamination of Organophosphates Using Mesoporous Silica Nanoparticles (MSNs)

Based on their continuous presence and threat in the environment, a highly specific visual detection system for organophosphorus compounds is needed. For this purpose, we have been working to develop a molecular trigger system incorporating an enzyme-inhibitor release process. Mesoporous silica nanoparticles (MSNs) have valuable physical properties, such as a synthetically controllable pore diameter, a large surface area (300-1600 m2/g), and large pore volumes (> 1.0 cc/g) that are vital to this specific application. In addition, MSNs also boast chemical inertness, stability at a variety of temperatures, and can be easily functionalized with a variety of reactive groups. In the studies reported here, luciferin was loaded into the pores, which were then capped by tethering organophosphorus hydrolase (OPH) to diethyl 4-aminobenzyl phosphate (DEABP), a competitive inhibitor that was covalently bound to the external surface of the MSNs. OPH has the ability to hydrolyze a large range of organophosphate compounds, rendering them non-toxic. Luciferin is a bioluminescent molecule that can also be viewed under a UV light when luciferase, O2, Mg2+, and ATP are present. Upon addition of paraoxon (an organophosphorus compound) to an aqueous suspension of MSNs, the OPH detaches from the competitive inhibitor (DEABP), releasing the luciferin, which in turn can be visually detected using UV light and also more quantitatively with fluorescence spectroscopy.