Enrichment and Detection of Rare Proteins with Aptamer-Conjugated Gold Nanorods

Abstract

Rare protein enrichment and sensitive detection hold great potential in biomedical studies and clinical practice. This work describes the use of aptamer-conjugated gold nanorods for the efficient enrichment of rare proteins from buffer solutions and human plasma. Gold nanorod (AuNR) surfaces were modified with a long PEG chain and a 15-mer thrombin aptamer for protein enrichment and detection. Studies of the effect of surface modification on enrichment efficiency of thrombin showed that a change of only one EG 6 linker unit, i.e., from 2EG 6 to 3EG 6 , could increase thrombin protein capture efficiency by up to 47%. Furthermore, a 1 ppm sample of thrombin in buffer could be enriched with around 90% efficiency using a low concentration (0.19 nM) of gold nanorod probe modified with 3EG 6 spacer, and with the same probe, effective capture was achieved down to 10 ppb (1 ng) thrombin in plasma samples. In addition to α-thrombin enrichment, prothrombin was also efficiently captured from plasma samples via gold nanorods conjugated with 15-mer thrombin aptamer. Our work demonstrates efficient enrichment of rare proteins using aptamer-modified nanomaterials, which can be used in biomarker discovery studies.

Reversible regulation of thrombin adsorption and desorption based on photoresponsive-aptamer modified gold nanoparticles

“…8A, an expected band can be seen in SDS-PAGE. This molecular weight of the band was around 68 KD, which indicated that this band may be the prothrombin that was also can be bind with APT15 [34]. From Fig.…”

Hybrid nanomaterial: biocolloidals

“…Rod-shaped AuNPs, known as "gold nanorods", show two LSPR bands that are defined as transverse and longitudinal bands. The transverse band is in the visible range of the spectrum, which is similar to that of a spherical AuNP, and longitudinal oscillation is in the NIR range of the spectrum (Herold et al, 2012;Yasun et al, 2012Yasun et al, , 2013Kang et al, 2015). The longitudinal band shifts to longer wavelengths (red shift) and shows stronger intensities when the aspect ratio increases.…”

“…Encapsulation of fluorescent dyes is one of the most important roles of SiO 2 NPs for bioimaging purposes. Huge loads of fluorophore molecules can be encapsulated in SiO 2 particles to act as a superfluorescent NPs (Kainz et al, 2010;Pergantis et al, 2012;Tan et al, 2012;Zhu et al, 2014;Helmbrecht et al, 2015;Luo et al, 2015). On the other hand, this encapsulation is also applicable to NPs that are not biocompatible.…”

BSA modification to reduce CTAB induced nonspecificity and cytotoxicity of aptamer-conjugated gold nanorods

“…The selected aptamer was modified with disulfide and fluorescein dye (FITC, FAM) at its 5`-terminus and 3`-terminus, respectively, using the same protocol that was previously reported. 31 …”