Aptamer-based label-free detection of PDGF using ruthenium(II) complex as luminescent probe

Abstract

We report a simple, cost-effective, and label-free detection method, consisting of a platelet-derived growth factor (PDGF) binding aptamer and hydrophobic Ru(II) complex as a sensor system for PDGF. The binding of PDGF with the aptamer results in the weakening of the aptamer-Ru(II) complex, monitored by luminescence signal. A substantial enhancement in the luminescence intensity of Ru(II) complex is observed in the presence of aptamer due to the hydrophobic interaction. Upon addition of PDGF, the luminescence intensity is decreased, due to the stronger interaction between the aptamer and PDGF resulting in the displacement of Ru(II) complex to the aqueous solution. Our assay can detect a target specifically in a complex medium such as the mixture of proteins, at a concentration of 0.8 pM.

Interaction of oxovanadium(iv)–salphen complexes with bovine serum albumin and their cytotoxicity against cancer

“…Lo et al [21][22][23] and Rajagopal and co-workers [24][25][26] have extensively studied the BSA binding properties of luminescent Re(I)-complexes and used them for cell imaging studies. Rajagopal and co-workers have also used ruthenium(II)bipyridine-calixarene 27 and ruthenium(II)-aptamer systems 28,29 recently in our laboratory to investigate conformational changes of proteins.…”

Carbazole–azine based fluorescence ‘off–on’ sensor for selective detection of Cu2+ and its live cell imaging

“…Although many analytical techniques have been developed, they are time consuming and expensive, and a simple, distinct reaction of toxic metal ions via colorimetric quantification is required. Thus, the development of fluorescence‐based sensors for metal ions has attracted much interest among the research community …”

“…Thus, the development of fluorescence-based sensors for metal ions has attracted much interest among the research community. [22][23][24][25][26][27] Cu 2+ is well known among transition metals as a fluorescent quencher due to its paramagnetic nature. It is therefore practically difficult to develop fluorescent sensors for the detection of Cu 2+ .…”

Turning an Aptamer into a Light-Switch Probe with a Single Bioconjugation

“…If the intercalating dye itself is a light-switch, then the aptamer probe will also be one. The probe is thus devised to have a higher response than label-free intercalator-based systems, 13 while at the same time limiting bioconjugation to a single DNA strand. In this design, use of a dye that only luminesces while intercalated will result in a turn- off probe, while one that is quenched by stacking with base pairs will result in a turn- on probe.…”

“…In each case, most of the dyes are intercalated both in the absence and in the presence of the analyte. Consequently, the responses observed were small and also turn-off. − The other two limitations, multiplex detection and detection in a complex aqueous sample, could in theory be resolved with a lanthanide-based probe . The narrow emission bands and long luminescence lifetimes of lanthanide complexes make them uniquely suited for multiplex detection and quantitative analysis in complex media via time-gated measurements.…”