Surface Plasmon Resonance Biosensors for Highly Sensitive Detection of Small Biomolecules

Mitchell, John S.; Wu, Yunqiu

doi:10.5772/7208

Cited by 5 publications

(1 citation statement)

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“…The steric hindrance can be described as the effect in which the physical presence of a ligand affects the relative positioning of a molecule and has been demonstrated to reduce biosensor performance [247,[249][250][251][252]. The steric hindrance could also occur between the analyte and the sensing surface [253], which causes a fouling surface and, hence, decreases the biosensor devices' sensitivity. The steric hindrance effect has been demonstrated in the literature to significantly reduce total aptamer binding at high target analyte concentrations [254].…”

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Carbon nanomaterials as platforms for biosensors and atomic switch network devices

Nguyen

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Carbon nanomaterials, such as carbon nanotubes (CNTs) and graphene, have attracted growing attention as sensing platforms for field effect transistor (FET) aptasensors due to their large surface area and real-time detection capability. Moreover, carbon nanotubes offer high levels of sensitivity for various analytes detection and use as network material to increase the stability in atomic switch network (ASN) devices. This thesis investigated the detection of small molecules using different carbon nanomaterial platforms, as well as the use of CNT networks for atomic switch networks. First, CNT FET aptasensors have been investigated for the detection of adenosine using two different aptamer sequences, a 35-mer and a 27-mer. Limits of detection were found for adenosine of 100 pM and 320 nM for the 35-mer and 27-mer aptamers, with dissociation constants of 1.2 nM and 160 nM, respectively. Upon analyte recognition, the 35-mer adenosine aptamer adopts a compact G-quadruplex structure, while the 27-mer adenosine aptamer changes to a folded duplex. Using the CNT FET aptasensor platform, adenosine could be detected with high sensitivity over the range of 100 pM to 10 µM, highlighting the suitability of the CNT FET aptasensor platform for high-performance adenosine detection. The aptamer restructuring format is critical for high sensitivity with the G-quadruplex aptasensor having a 130-fold smaller dissociation constant than the duplex forming aptasensor. Second, a comparison between CNT and graphene FET aptasensors has been conducted. CNT and graphene both showed high sensitivity over the detection range of 1 nM to 10 mM, with dissociation constants of 7.7 nM for CNT and 5.7 nM for graphene. Compared to graphene FET aptasensors, CNT FET showed eight times higher sensitivity. CNT FETs have also performed for the study of dose-dependent sensing to evaluate the feasibility of realizing accurate biosensors. Regardless of the initial ligand concentration, the real-time current responses showed a similar signal on the first added concentration. These sensing signals could be caused by CNT platforms with sensing hotspots between CNT junctions, or by over-detecting sensing sites, rather than accurately responding to analyte levels. Overall, the sensing performance of CNT FET aptasensors is influenced by the initial concentrations, with the sensitivity increasing for lower initial concentrations near the detection limit. Finally, distribution of silver nanowires (AgNWs) in the ASN device results in Joule heating at nanowire contact points, resulting in failure of AgNWs in the network. To solve this issue, a combination of CNTs has been used to improve the electrical conductivity of ASN devices. A simple fabrication and measurement method for ASN-based CNT devices has been developed. This technique involves drop-casting silver nanowires onto a patterned carbon nanotube network and then exposing it to sulfur gas to activate the nanowires. Because of the combination of AgNWs and carbon nanotubes, the ASN system improved contact resistance and switching events. This work is the first to introduce an Ag/Ag2S/Ag carbon nanotube that can be potentially applied to neural computing applications. Plans for future work are presented at the end of this thesis.

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Carbon nanomaterials as platforms for biosensors and atomic switch network devices

Nguyen

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Affinity-Based Nanoarchitectured Biotransducer for Sensitivity Enhancement of Surface Plasmon Resonance Sensors for In Vitro Diagnosis: A Review

Nangare

Patil

2020

ACS Biomater. Sci. Eng.

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Despite the indisputable benefits and advancement of science, technology, and civilization, early diagnosis of healthcare is still a challenging field for the scientific fraternity. The detection of biomarkers is a crucial attribute of prognosis and diagnosis of disease. Out of numerous techniques, surface plasmon resonance (SPR) bestows countless benefits, including in situ, label-free, and real-time assessment, etc., which authorizes the analysis of molecular binding occurrences between biotransducers and biomarkers. In addition, SPR with low-molecular-weight biomarkers lacks selectivity and sensitivity, which ultimately affects binding kinetics. This, in turn, leads to the remarkable development and implementation of numerous selectivity and sensitivity enhancement methods. Among the various noticeable strategies, because of selectivity and sensitivity enrichment substrate for SPR biosensors, affinity-based nanoarchitectured biotransducers stand out as being the best substitute. The present review elaborates significant advances made in the research based on affinity biotransducers for in vitro diagnosis using SPR biosensors for biomarker sensing. Moreover, most recent trends and challenges in designing and application of nanoarchitectured affinity biotransducer-based SPR biosensors for detecting low-concentration biomarkers have been reviewed comprehensively. This present review may assist the scientific fraternity in designing an ultramodern novel SPR approach based on affinity biotransducers, along with improved selectivity and sensitivity of SPR biosensors for in vitro and real-time diagnostic applications.

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ELISA Assay for estimation of Prednisolone Drug Using Bridge Heterology in Enzyme Conjugates

Sonkar

Kumar

Oberoi³

et al. 2023

Preprint

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The introduction of spacers in coating steroid protein complex and / or enzyme conjugates or immunogen is known to exert an influence on the sensitivity of steroid enzyme immunoassays. We have introduced different homobifunctional spacers between enzyme and prednisolone (PSL) moiety having atomic length 3 to 10 and studied their influence on functional parameters such as sensitivity and specificity of PSL enzyme immunoassays. In this study, four enzyme conjugates of PSL-21-HS and HRP were prepared by N-Hydroxy Succinimide mediated carbodiimide reaction, these were PSL-21-HS-adipic acid dihydrazide (ADH)-HRP, PSL-21-HS- carbohydrazide (CH)-HRP, PSL-21-HS-ehylenediamine (EDA)-HRP and PSL-21-HS- urea (U)-HRP. The assays were developed using these enzymes conjugate with antibody raised against PSL-21-HS-BSA immunogen. The sensitivity of the PSL assays after insertion of bridge in enzyme conjugate were 1.22 ng/mL, 0.59 ng/mL, 0.48 ng/mL and 0.018 ng/mL with ADH, CH, EDA and urea as spacer respectively. Among all four combinations, PSL-21-HS-BSA antibody and PSL-21-HS-U-HRP enzyme conjugate gave better sensitivity and showed cross-reaction with less number of steroids. The percent recovery of PSL from the exogenously spiked human serum pools was in the range of 88.32-102.50 %. The intra and inter assay CV % was < 8.46%. The PSL concentration was estimated in the serum samples of patients on PSL treatment. The serum PSL values obtained by this method correlated well with the commercially available kit (r2 = 0.98). The present study, suggests that the nature of the spacer is related to assay sensitivity and not the spacer length.

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Surface Plasmon Resonance Biosensors for Highly Sensitive Detection of Small Biomolecules

Cited by 5 publications

References 135 publications

Carbon nanomaterials as platforms for biosensors and atomic switch network devices

Carbon nanomaterials as platforms for biosensors and atomic switch network devices

Affinity-Based Nanoarchitectured Biotransducer for Sensitivity Enhancement of Surface Plasmon Resonance Sensors for In Vitro Diagnosis: A Review

ELISA Assay for estimation of Prednisolone Drug Using Bridge Heterology in Enzyme Conjugates

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