Low-Fouling Surface Plasmon Resonance Sensor for Highly Sensitive Detection of MicroRNA in a Complex Matrix Based on the DNA Tetrahedron

Abstract

Antifouling surfaces that could reduce nonspecific adsorption from a complex matrix are a great challenge in surface plasmon resonance (SPR) sensors. An antifouling surface made by the covalent attachment of DNA tetrahedron probes (DTPs) onto gold surfaces demonstrated superior antifouling property against protein and cell. DTPmodified Au (DTPs−Au) film for two single protein samples (1 mg/mL myoglobin, 48 mg/mL HSA) and five complex matrices (100% serum, 100% plasma, 9.85 × 10 8 red cells/mL, 5% whole blood, and cell lysate) had low or ultralow adsorption amounts (≤8.0 ng/cm 2 ). More interestingly, DTPs−Au film could also avoid Au deposition on the surface in the process of the catalytic growth of gold nanoparticles (AuNPs). Thus, a low-fouling and sensitive SPR sensor for miRNA detection in a complex matrix was developed by integrating DTPs−Au film with the catalytic growth of AuNPs. Exploiting the amplification of catalytic growth of AuNPs, the detection limit was 0.8 fM toward target let-7a. Moreover, the SPR sensor revealed excellent selectivity and could distinguish let-7a from homologous family. More importantly, the SPR sensor could be feasible for determining miRNA in 100% human serum and cancer cell lysates, and the results of detecting miRNA from cancer cells were in excellent accord with the results obtained using qRT-PCR. This assay may have great potential as an miRNA quantification method in complex samples.

DNA nanotechnology approaches for microRNA detection and diagnosis

“…Target microRNA binds and releases the fluorophore-containing strand in the duplex, releasing it from the quenching nanoparticle and increasing fluorescence. In another version, Wang and co-workers used DNA tetrahedral probes on gold electrodes and combined it with gold nanoparticles to detect microRNAs using surface plasmon resonance (SPR) (117). In this strategy the SPR signal can further be enhanced by deposition of gold on the nanoparticles.…”

Low-Fouling Substrates for Plasmonic Sensing of Circulating Biomarkers in Biological Fluids

“…However, nonspecific binding results in low signal-to-noise ratios and lower sensitivity analysis [34,37]. Specifically, the adhesion of nonspecific matter to the bioactive surface of sensor chips may generate large noise signals that disrupt the biosensing response, hindering the read-out triggered by the target analyte [40]. Therefore, further attempts need to be concentrated on the development of biointerfaces capable of preserving the activity of the biorecognition element immobilized on the nanostructured surface while maintaining unaltered the sensitivity and signal response.…”

“…Since the analytical performance of plasmonic biosensors enables biomarker detection in the nanomolar to picomolar range, antifouling coatings should confer excellent stability and compatibility to the immobilized biological receptor in order to allow analyte recognition at very low concentrations with the sufficient accuracy and sensitivity. Hence, the design of antifouling materials should rely on the formation of hydration layers and/or the utilization of long-chain polymers where steric hindrance may contribute to both suppress undesired fouling and resist nonspecific adsorption [11,34,40].…”

DNA-Programmed Chemical Synthesis of Polymers and Inorganic Nanomaterials

“…When the complementary oligonucleotides were positioned at the desired distances along the DNA duplex, defined AuNP dimers and trimers with controllable spacing could be achieved [64]. Since then, the self-assembly of inorganic nanoparticles templated by DNA oligonucleotide chains has advanced rapidly, and has found broad application in the construction of diagnostic tools for nucleic acid, protein and bacteria [65][66][67][68][69], as intracellular probes [70][71][72][73], and as selective detection biosensors [74][75][76] and gene regulators, etc. [77].…”