title: In situ induced metal-enhanced fluorescence: a new strategy for biosensing the total acetylcholinesterase activity in sub-microliter human whole blood.
abstract: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities (i.e., total AChE) in human blood are biomarkers for theranostic monitoring of organophosphate neurotoxin-poisoned patients. We developed an ultra-sensitive method to detect the total AChE activity in sub-microliter human whole blood based on in situ induced metal-enhanced fluorescence (MEF). Both AChE and BChE can catalyze the hydrolysis of the acetylthiocholine (ATCh) substrate and produce positively-charged thiocholine (TCh). TCh can reverse the negatively-charged surface of core-shell Ag@SiO2 nanoparticles (NPs). The negatively-charged fluorescent dye (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) is then confined to the surface of Ag@SiO2 NPs and generates an enhanced fluorescence signal in situ. Changes in the surface charge of Ag@SiO2 NPs are monitored by Zeta potential, and the MEF effect is confirmed by the measurements of fluorescence time decay. AChE activity has a dynamic range of 0 U/mL to 0.005 U/mL and a detection limit of 0.05 mU/mL. The total AChE activity in the sub-microliter human whole blood could be determined; the results were further validated. Therefore, combining the AChE catalytic reaction with MEF provides a simple, ultra-sensitive, and cost-effective "in situ MEF" approach to determine the total AChE activity in human whole blood sample down to sub-microliters without matrix interferences. The strategy also allows potential usage in other tissues and other fields.
authors: Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Xi'an 710062, PR China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors: KeKe
authors: K
authors: Ma
authors: Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Xi'an 710062, PR China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors: Lu
authors: L
authors: Lu
authors: Lab Center, the Third Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors: Zongli
authors: Z
authors: Qi
authors: Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Xi'an 710062, PR China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors: Jingjing
authors: J
authors: Feng
authors: Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Xi'an 710062, PR China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors: Caixia
authors: C
authors: Zhuo
authors: Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Xi'an 710062, PR China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China. Electronic address: ydzhang@snnu.edu.cn.
authors: Yaodong
authors: Y
authors: Zhang
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood / Q000302:isolation & purification*; D000122:Acetylthiocholine / Q000737:chemistry / Q000378:metabolism; D015374:Biosensing Techniques; D002384:Catalysis; D002800:Cholinesterase Inhibitors / Q000737:chemistry; D005453:Fluorescence; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D002800:Cholinesterase Inhibitors; D000122:Acetylthiocholine; D012822:Silicon Dioxide; D000110:Acetylcholinesterase
keywords: Acetylcholinesterase; Activity; Alzheimer's disease; Butyrylcholinesterase; Metal-enhanced fluorescence