title: Facile synthesis of gold-silver alloy nanoparticles for application in metal enhanced bioluminescence.
abstract: In the present study we explored metal enhanced bioluminescence in luciferase enzymes for the first time. For this purpose a simple and reproducible one pot synthesis of gold-silver alloy nanoparticles was developed. By changing the molar ratio of tri-sodium citrate and silver nitrate we could synthesize spherical Au-Ag colloids of sizes ranging from 10 to 50 nm with a wide range of localized surface plasmon resonance (LSPR) peaks (450-550 nm). The optical tunability of the Au-Ag colloids enabled their effective use in enhancement of bioluminescence in a luminescent bacterium Photobacterium leiognathi and in luciferase enzyme systems from fireflies and bacteria. Enhancement of bioluminescence was 250% for bacterial cells, 95% for bacterial luciferase and 52% for firefly luciferase enzyme. The enhancement may be a result of energy transfer or plasmon induced enhancement. Such an increase can lead to higher sensitivity in detection of bioluminescent signals with potential applications in bio-analysis.
authors.affiliation: Fermentation Technology and Bioengineering Department, CSIR-Central Food Technological Research Institute, Mysore-570020, Karnataka, India. msthakur@cftri.res.in msthakur@yahoo.co.in.
authors.forename: K S
authors.initials: KS
authors.lastname: Abhijith
authors.forename: Richa
authors.initials: R
authors.lastname: Sharma
authors.forename: Rajeev
authors.initials: R
authors.lastname: Ranjan
authors.forename: M S
authors.initials: MS
authors.lastname: Thakur
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000818:Animals; D002951:Citrates / Q000737:chemistry; D003102:Colloids / Q000737:chemistry; D048888:Fireflies / Q000201:enzymology; D006046:Gold / Q000737:chemistry; D049453:Luciferases, Bacterial / Q000737:chemistry / Q000378:metabolism; D049409:Luciferases, Firefly / Q000737:chemistry / Q000378:metabolism; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D010776:Photobacterium / Q000201:enzymology; D012834:Silver / Q000737:chemistry; D012835:Silver Nitrate / Q000737:chemistry; D020349:Surface Plasmon Resonance
chemical_list: D000497:Alloys; D002951:Citrates; D003102:Colloids; C514290:trisodium citrate; D012834:Silver; D006046:Gold; D012835:Silver Nitrate; D049409:Luciferases, Firefly; D049453:Luciferases, Bacterial