Surface plasmon resonance investigation of DNA hybridization on a sensor surface using gold nanoparticles modified by specific oligonucleotides

摘要

Aim. To investigate an influence of the oligonucleotide concentration on their immobilizationon the surface of gold nanoparticles (AuNPs), and to study interactions between the AuNPsmodified by various oligonucleotides and the oligonucleotides immobilized on the chip of theSPR-based DNA-sensor. Methods. Oligonucleotide immobilization on the surface of AuNPswas investigated by fluorescence spectrometry. The interactions of citrate-stabilized AuNPsmodified by oligonucleotides with the oligonucleotides immobilized on the chip of the DNAsensorwere studied by the surface plasmon resonance spectrometry. Results. The initial oligonucleotideconcentration influences the level of their immobilization on the surface of citratestabilizedAuNPs: up to 200 nM the dependence was close to linear, and then saturation wasobserved at ~ 26 molecules per particle or ~ 0.5×1013 molecules cm–2. In contrast, the efficiencyof immobilization gradually decreased with an increase in the initial oligonucleotideconcentration. Using the SPR-based DNA-sensor, the efficient hybridization between oligonucleotidesimmobilized on the sensor chip and complementary oligonucleotides of variouslength (short T2-11m and long T2-18m) immobilized on the surface of AuNPs was demonstrated.In case of AuNPs modified by short oligonucleotides, efficient thermal and chemicalregenerations of the bioselective element of the DNA-sensor were achieved.Conclusions. Oligonucleotide immobilization on the surface of AuNPs directly depends onthe initial oligonucleotide concentration, whereas the initial oligonucleotide concentration and the efficiency of their immobilization on the surface of AuNPs demonstrate the inverse relationship. The efficient hybridization of the oligonucleotides of various lengths immobilized on AuNPs with the oligonucleotides immobilized on the sensor surface as well as the possibility of thermal or chemical regeneration allow the sensor reuse and a strong amplification of the sensor signal.