title: Choline-induced selective fluorescence quenching of acetylcholinesterase conjugated Au@BSA clusters.
abstract: We have developed a highly selective sensitive fluorescent detection of acetylcholine (ACh) using bovine serum albumin (BSA) protected atomically precise clusters of gold. The gold quantum clusters (AuQC@BSA) synthesized using bovine serum albumin and conjugated with acetylcholinesterase (AChE), an enzyme specific for acetylcholine, resulting in AuQC@BSA-AChE. The enzyme, AChE hydrolyzes acetylcholine (ACh) to choline (Ch) which in turn interacts with AuQC@BSA-AChE and quenches its fluorescence, enabling sensing. We have carried out the real time monitoring of the hydrolysis of ACh using electrospray ionization mass spectrometry (ESI MS) to find out the mechanism of fluorescent quenching. The validity of present method for determination of concentration of acetylcholine in real system such as blood was demonstrated. Further, the sensor, AuQC@BSA-AChE can be easily coated on paper and an efficient and cheap sensor can be developed and detection limit for ACh is found to be 10nM. The fluorescent intensity of AuQC@BSA-AChE is sensitive towards acetylcholine in range of 10nM to 6.4µM. This suggests that AuQC@BSA-AChE has an excellent potential to be used for diagnosis of various neuropsychological and neuropsychiatric disorders.
authors.affiliation: Department of Chemistry, Indian Institute of Space Science and Technology, Valiyamala, Thiruvananthapuram 695547, India.
authors.forename: Meegle S
authors.initials: MS
authors.lastname: Mathew
authors.affiliation: DST Unit of Nanoscience (DST UNS), and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
authors.forename: Ananya
authors.initials: A
authors.lastname: Baksi
authors.affiliation: DST Unit of Nanoscience (DST UNS), and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India. Electronic address: Pradeep@iitm.ac.in.
authors.forename: T
authors.initials: T
authors.lastname: Pradeep
authors.affiliation: Department of Chemistry, Indian Institute of Space Science and Technology, Valiyamala, Thiruvananthapuram 695547, India. Electronic address: kjoseph.iist@gmail.com.
authors.forename: Kuruvilla
authors.initials: K
authors.lastname: Joseph
mesh_terms: D000109:Acetylcholine / Q000032:analysis / Q000097:blood*; D000110:Acetylcholinesterase / Q000737:chemistry*; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods; D002417:Cattle; D002794:Choline / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005453:Fluorescence; D006046:Gold / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D004800:Enzymes, Immobilized; D012710:Serum Albumin, Bovine; D006046:Gold; D000110:Acetylcholinesterase; D002794:Choline; D000109:Acetylcholine
keywords: Acetylcholine (ACh); Acetylcholinesterase (AChE); Choline; Fluorescence; Quantum Clusters; Quenching