Determination of urinary adenosine using resonance light scattering of gold nanoparticles modified structure-switching aptamer

A novel sensitive method has been developed for the detection of adenosine (AD) in human urine by using enhanced resonance light scattering (RLS). This method is based on the specific recognition and signal amplification of adenosine aptamer (Apt) coupled with gold nanoparticles (GNPs) via G-quartet-induced nanoparticle assembly, which was fabricated by triggering a structure switching of the 3' terminus G-rich sequence and aptamer duplex. RLS signal linearly correlated with the concentration of adenosine over the range of 6-115 nM. The limit of detection (LOD) for adenosine is 1.8 nM with relative standard deviations (RSD) of 2.90-4.80% (n = 6). The present method has been successfully applied to determination of adenosine in real human urine, and the obtained results were in good agreement with those obtained by the HPLC method. Our investigation shows that the combination of the excellent selectivity of aptamer with the high sensitivity of the RLS technique could provide a promising potential for aptamer-based small molecule detection, and be beneficial in extending the application of RLS. (C) 2009 Elsevier Inc. All rights reserved.