title: Development of a label-free gold nanoparticle-based colorimetric aptasensor for detection of human estrogen receptor alpha.
abstract: The increasing demand for easily available and low-cost diagnostics has fuelled the development of aptasensors as platforms for rapid, sensitive, and point-of-care testing of target analytes. Recently, gold nanoparticle (AuNP)-based aptasensors have attracted wide recognition owing to their color transition properties which allow real-time rapid sensing of targets. In this study, we utilized the color transition property of aptamer-functionalized AuNPs to detect and quantify estrogen receptor alpha (ERα), a key biomarker protein in breast cancer. We found that the coating of AuNPs with unmodified ERα-RNA aptamer (GGGGUCAAGGUGACCCC) makes them resistant to salt-induced aggregation. However, addition of ERα to the aptamer-protected AuNPs results in their spontaneous aggregation as evident from a color transition from wine red to deep blue. On the basis of this, we developed an ERα aptasensor, with limits of detection and quantification of 0.64 and 2.16 ng/mL, respectively; the aptasensor can efficiently detect and quantify ERα in a working range of 10 ng/mL-5μg/mL protein. Validation of the aptasensor on cellular extracts of ERα-positive MCF-7 and ERα-deficient MDA-MB-231 breast cancer cells showed a target-selective response in ERα-positive samples but not in cellular extracts of ERα-deficient breast cancer cells. Further, the small size and simple fabrication chemistry of aptamers provide an additional benefit to make the ERα aptasensor a potentially useful and cost-effective tool in point-of-care analyses of ERα.
authors.affiliation: Department of Chemical and Systems Biology, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India.|CSIR-Institute of Genomics and Integrative Biology, Academy of Scientific and Innovative Research, Delhi, 110007, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Ahirwar
authors.affiliation: Department of Chemical and Systems Biology, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India. pnahar@igib.res.in.|CSIR-Institute of Genomics and Integrative Biology, Academy of Scientific and Innovative Research, Delhi, 110007, India. pnahar@igib.res.in.
authors.forename: Pradip
authors.initials: P
authors.lastname: Nahar
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods*; D047628:Estrogen Receptor alpha / Q000032:analysis* / Q000235:genetics; D006046:Gold / Q000737:chemistry; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D006046:Gold
keywords: Breast cancer; Colorimetric aptasensor; Estrogen receptor alpha; Gold nanoparticles; RNA aptamer