title: Theophylline detection using an aptamer and DNA-gold nanoparticle conjugates.
abstract: A detection system for theophylline that combined the recognition properties of an aptamer and the plasmonic response of gold nanoparticles (AuNPs) is presented. The aptamer was used as a linker for AuNPs functionalized with complementary sequences to the aptamer (DNA-AuNPs), producing supramolecular complexes that disassemble when exposed to theophylline due to aptamer binding. The detection event was reported as a change in the AuNPs plasmonic peak and intensity. Addition of a spacer on the DNA immobilized on the AuNPs facing the aptamer binding site improved the aggregates' response, doubling the detection range of system response to theophylline. Modification of the oligonucleotides immobilized on the AuNPs that reduced the interparticle distance in the aggregated state suppressed their response to theophylline and addition of the spacer recovered it. This work demonstrated that the design of oligonucleotides immobilized on the AuNPs could be used to improve their plasmonic response without affecting aptamer performance.
authors.affiliation: Applied Biotechnology Branch, Human Effectiveness Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433, USA.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Chávez
authors.forename: Wanda
authors.initials: W
authors.lastname: Lyon
authors.forename: Nancy
authors.initials: N
authors.lastname: Kelley-Loughnane
authors.forename: Morley O
authors.initials: MO
authors.lastname: Stone
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013806:Theophylline / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D004247:DNA; D013806:Theophylline