Acetylcholinesterase-Based Organophosphate Nerve Agent Sensing Photonic Crystal

• Published in: Analytical chemistry (Washington) Vol. 77; no. 6; pp. 1596 - 1600
• Main Authors: Walker, Jeremy P, Asher, Sanford A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.03.2005
• Subjects: Acetylcholinesterase - metabolism; Analytical chemistry; Aqueous solutions; Arrays; Biosensing Techniques - methods; Chemical Warfare Agents - analysis; Chemistry; Colloids; Crystallization; Crystals; Exact sciences and technology; General, instrumentation; Parathion - analysis; Phosphorus content; Polymers; Parathion; Enzyme; Ultratrace compound; Pesticides; Esterases; Acetylcholinesterase; Chemical sensor; Carboxylic ester hydrolases; Photonic crystal; Molecular recognition; Hydrolases; Organophosphorus compounds; Hydrogel; Aqueous solution
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac048562e

We developed a polymerized crystalline colloidal array (PCCA) photonic crystal sensing material that senses the organophosphorus compound parathion at ultratrace concentrations in aqueous solutions. A periodic array of colloidal particles is embedded in a hydrogel network with a lattice spacing such that it Bragg diffracts visible light. The molecular recognition agent for the sensor is the enzyme acetylcholinesterase (AChE), which binds organophosphorus compounds irreversibly, creating an anionic phosphonyl species. This charged species creates a Donnan potential, which swells the hydrogel network, which increases the embedded particle array lattice spacing and causes a red-shift in the wavelength of light diffracted. The magnitude of the diffraction red-shift is proportional to the amount of bound parathion. These AChE-PCCAs act as dosimeters for parathion since it irreversibly binds. Parathion concentrations as low as 4.26 fM are easily detected.