Laser ablation-based one-step generation and bio-functionalization of gold nanoparticles conjugated with aptamers

Abstract

<p>Abstract</p> <p>Background</p> <p>Bio-conjugated nanoparticles are important analytical tools with emerging biological and medical applications. In this context, <it>in situ </it>conjugation of nanoparticles with biomolecules via laser ablation in an aqueous media is a highly promising one-step method for the production of functional nanoparticles resulting in highly efficient conjugation. Increased yields are required, particularly considering the conjugation of cost-intensive biomolecules like RNA aptamers.</p> <p>Results</p> <p>Using a DNA aptamer directed against streptavidin, <it>in situ </it>conjugation results in nanoparticles with diameters of approximately 9 nm exhibiting a high aptamer surface density (98 aptamers per nanoparticle) and a maximal conjugation efficiency of 40.3%. We have demonstrated the functionality of the aptamer-conjugated nanoparticles using three independent analytical methods, including an agglomeration-based colorimetric assay, and solid-phase assays proving high aptamer activity. To demonstrate the general applicability of the <it>in situ </it>conjugation of gold nanoparticles with aptamers, we have transferred the method to an RNA aptamer directed against prostate-specific membrane antigen (PSMA). Successful detection of PSMA in human prostate cancer tissue was achieved utilizing tissue microarrays.</p> <p>Conclusions</p> <p>In comparison to the conventional generation of bio-conjugated gold nanoparticles using chemical synthesis and subsequent bio-functionalization, the laser-ablation-based <it>in situ </it>conjugation is a rapid, one-step production method. Due to high conjugation efficiency and productivity, <it>in situ </it>conjugation can be easily used for high throughput generation of gold nanoparticles conjugated with valuable biomolecules like aptamers.</p