Endonuclease controlled aggregation of gold nanoparticles for the ultrasensitive detection of pathogenic bacterial DNA.
The development of an ultrasensitive biosensor for the low-cost and on-site detection of pathogenic DNA could transform detection capabilities within food safety, environmental monitoring and clinical diagnosis. Herein, we present an innovative approach exploiting endonuclease-controlled aggregation of plasmonic gold nanoparticles (AuNPs) for label-free and ultrasensitive detection of bacterial DNA. The method utilizes RNA-functionalized AuNPs which form DNA-RNA heteroduplex structures through specific hybridization with target DNA. Once formed, the DNA-RNA heteroduplex is susceptible to RNAse H enzymatic cleavage of the RNA probe, allowing the target DNA to liberate and hybridize with another RNA probe. This continuously happens until all of the RNA probes are cleaved, leaving the nanoparticles unprotected and thus aggregated upon exposure to a high electrolytic medium. The assay is ultrasensitive, allowing the detection of target DNA at femtomolar level by simple spectroscopic analysis (40.7 fM and 2.45fM as measured by UV-vis and dynamic light scattering (DLS), respectively). The target DNA spiked food matrix (chicken meat) is also successfully detected at a concentration of 1.2pM (by UV-vis) or 18.0fM (by DLS). In addition to the ultra-high sensitivity, the total analysis time of the assay is less than 3h, thus demonstrating its practicality for food analysis.
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 18-30 Malone Road, Belfast BT9 5BN, UK.
Claire
C
McVey
School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
Fumin
F
Huang
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 18-30 Malone Road, Belfast BT9 5BN, UK.
Christopher
C
Elliott
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 18-30 Malone Road, Belfast BT9 5BN, UK. Electronic address: c.cao@qub.ac.uk.
Cuong
C
Cao
D000818:Animals; D002169:Campylobacter Infections / Q000382:microbiology; D016123:Campylobacter jejuni / Q000302:isolation & purification*; D002645:Chickens; D003124:Colorimetry / Q000379:methods*; D015342:DNA Probes / Q000737:chemistry; D004269:DNA, Bacterial / Q000032:analysis*; D005504:Food Analysis / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009693:Nucleic Acid Hybridization / Q000379:methods; D011200:Poultry / Q000382:microbiology*; D015347:RNA Probes / Q000737:chemistry; D016914:Ribonuclease H / Q000737:chemistry
D015342:DNA Probes; D004269:DNA, Bacterial; D015347:RNA Probes; D006046:Gold; D016914:Ribonuclease H
Aggregation; DNA detection; Endonuclease enzyme; Gold nanoparticles; RNAse H