Sensitivity Limit of Nanoparticle Biosensors in the Discrimination of Single Nucleotide Polymorphism

Abstract

Detection of single nucleotide polymorphisms (SNP) by selective aggregation of nanoparticles offers a rapid determination of cancer biomarkers, detectable by the naked eye. The main factor limiting the sensitivity of such colloidal sensors is the number of available target DNA molecules that can induce aggregation and thereby transduce an optical output signal. Although particle size is an obvious parameter of choice toward the modulation of the target-to-particle ratio at constant metal concentration, it is often omitted due to difficulties in the synthesis of particles with suitable size or to the limited colloidal stability of large particles stabilized with DNA. We present here a systematic study of SNP detection using gold nanoparticles of various sizes (13, 46 and 63 nm), using a conventional sandwich assay. We found that a five-fold increase in particle size, at constant gold concentration, leads to an improvement in the limit of detection by three orders of magnitude, which is 5, 0.1, and 0.05 nM for 13, 46 and 63 nm, respectively. This assay allows the SNP detection down to 10.85 fmol within less than 10 minutes. We conclude that a target-to-particle ratio equal to 4 sets the limit of detection and sensitivity of the assay, regardless of particle size.

The response of citrate functionalised gold and silver nanoparticles to the addition of heavy metal ions

“…Au and Ag NPs are two of the most widely studied NPs, with applications being found within such fields as: Chemical and biological sensing, catalysts, electronics and photonics, [1][2][3][4][5][6][7][8][9] all of which make use of the applications of localised surface plasmon resonance (LSPR). 10,11 LSPR is the coherent oscillation of free electrons at the surfaces of the NPs and is spectrally observed as an intense absorbance maximum in the visible part of the electromagnetic spectrum.…”

Strategies for the Development of Metallic‐Nanoparticle‐Based Label‐Free Biosensors and Their Biomedical Applications

“…AuNP colorimetric detection of up to single base pair mismatched DNA difficultyi nthe adsorption of longer length DNA by AuNPs [43] AuNP colorimetric NP size effect in the detection of mismatched DNA and importance of target-to-particle ratio for aggregation of NPs interference from other biomolecules;atmospheric effects on the detection processwere not tested [47] AuNP colorimetric detection of mismatchedD NA in longer length ssDNA and dsDNA, as well as the effect of chemical modification of DNA on the detection process lower sensitivity and specificity in longer length DNA [49] AgNP fluorescence use of NC in the fluorescence detection of mutant genes LOD was little bit highert han other reported mechanism [59] AgNP fluorescence fluorescence turn-on sensor for the detection of AChEa ctivity impact of different lengths of DNA on fluorescence intensityo fDNA-Ag NCs was not studied [65] CuNP fluorescence methodt od etect sulfur-containing drugse ffect of the presenceo fa tmospheric thiol-containing compounds was not illustrated [80] CuNP fluorescence recognition of ALP activityP ie xtraction methodw as not presented because Pi inhibits ALP activity and can interfere with real data [82] AuNP SPR examined the entrance mechanism of AuNPs into HeLa cancer cell no band was observed if the concentration of AuNPs was very low and only 50 %o ft he area of an evanescent field sensor was coveredb ycells [94] AuNP SPR developed an on-chipL SPR-based biosensor for multiplex detection of breast cancer biomarkers LOD of CA125 and CEA protein biomarkers for breast cancer are higher than the clinically relevant amount [100] AgNP SPR used triangularAgNPs to sense serum p53 protein effect of other proteinsa nd concentrations on LSPR band shifting was not studied [104] AuNP SERS demonstrated away to prepare uniform AuNPs up to alarge area SERS shift near 518 cm À1 was not defined [117] AuNP SERS studied lipidconstitution and modificationinc ompositions after addition of CH groups by the attachment of AuNPs effect of various chemically stabilizedA uNPs was not represented [118] AgNP SERS studied site-specific drug delivery and intercellular molecular determination with Ag@NGO cell viability for normal cells was much lower than that of cancer cells [126] AgNP SERSr epresented the SERS-based cascade amplificationb ioassay methodf or the determination of miRNA involved multiple washinga nd ultracentrifugation steps, which could affectthe sensing performance [132] CuNP SERSd emonstrated the preparation of CuNPsb yP LAL method involved the oxidation of CuNPs, whichc ould affect the band position [137] AlNP MEFutilized AlNPs for increasing fluorescence of adenine spacing effect of NPs and analytea nd interference from foreign molecules werenot explored [152] AgNP MEFrevealedt he effect of spacing between fluorophorea nd AgNPs, density and interparticle distance, and spectral overlap between AgNPs and fluorophores on fluorescenceemission impact of d...…”

“…Although many methods exist for the detection of SNPs, these techniques suffer from a low discrimination ratio, which requires highly sensitive SNP detection. Sanromán‐Iglesias and co‐workers proposed the effect of particle size on the precise and specific detection of the BRCA1 mutant gene; this is a biomarker for the identification of breast and ovarian cancer . They followed the sandwich assay method, which involved the inclusion of target molecules to the mixture of probe AuNPs.…”

Streptavidin-Coated Au Nanoparticles Coupled with Biotinylated Antibody-Based Bifunctional Linkers as Plasmon-Enhanced Immunobiosensors

“…Many efforts have been made to understand the principle and the phenomena of nanoparticle aggregation and to utilize it for desirable sensing applications. So far, the size and shape of NPs have been investigated for their effect on enhancing the biosensor performance. − However, the effect of another potentially controllable property of NPs, namely their number density ( D n , number of particles in a given volume), has not been investigated.…”