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Single step nanoplasmonic immunoassay for the measurement of protein biomarkers.

Prabhulkar S, de la Zerda A, Paranjape A, Awdeh RM - Biosensors (Basel) (2013)

Bottom Line: This nanoplasmonic immunoassay can act as a simple, selective, sensitive strategy for effective disease diagnosis.It offers advantages such as wide detection range, increased speed of analysis (due to fewer incubation/washing steps), and no label development as compared to traditional immunoassay techniques.Our future goal is to incorporate this detection strategy onto a microfluidic platform to be used as a point-of-care diagnostic tool.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Miami-Bascom Palmer Eye Institute, Miami, FL 33136, USA; E-Mails: sprabhulkar@med.miami.edu (S.P.); asparanjape@gmail.com (A.P.).

ABSTRACT
A nanoplasmonic biosensor for highly-sensitive, single-step detection of protein biomarkers is presented. The principle is based on the utilization of the optical scattering properties of gold nanorods (GNRs) conjugated to bio-recognition molecules. The nanoplasmonic properties of the GNRs were utilized to detect proteins using near-infrared light interferometry. We show that the antibody-conjugated GNRs can specifically bind to our model analyte, Glucose Transporter-1 (Glut-1). The signal intensity of back-scattered light from the GNRs bound after incubation, correlated well to the Glut-1 concentration as per the calibration curve. The detection range using this nanoplasmonic immunoassay ranges from 10 ng/mL to 1 ug/mL for Glut-1. The minimal detectable concentration based on the lowest discernable concentration from zero is 10 ng/mL. This nanoplasmonic immunoassay can act as a simple, selective, sensitive strategy for effective disease diagnosis. It offers advantages such as wide detection range, increased speed of analysis (due to fewer incubation/washing steps), and no label development as compared to traditional immunoassay techniques. Our future goal is to incorporate this detection strategy onto a microfluidic platform to be used as a point-of-care diagnostic tool.

No MeSH data available.


Related in: MedlinePlus

Extinction spectrum of gold nanorods (GNRs) (black line) and relative intensity of (optical coherence tomography) (OCT) imaging light (red line). Inset: transmission electron microscopy (TEM) image of bare GNRs corresponding to longitudinal peak of 840 nm.
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biosensors-03-00077-f001: Extinction spectrum of gold nanorods (GNRs) (black line) and relative intensity of (optical coherence tomography) (OCT) imaging light (red line). Inset: transmission electron microscopy (TEM) image of bare GNRs corresponding to longitudinal peak of 840 nm.

Mentions: GNRs were selected as the indicator label for the immunoassay due to their tunable aspect ratios and high quality factor [6,15]. The tunability of optical resonances is of crucial importance, where nanostructures have to be configured to a selected wavelength such as the central wavelength of the illumination source. The dimensions of the GNRs are closely related to their light scattering and absorbing capabilities. The working principle of OCT is related to the capture and analysis of light backscattered from sample, thus we are interested in preferentially scattering nanoparticles [12]. The extinction spectra of the GNRs is characterized by two peaks, the larger/dominant peak corresponding to the longitudinal surface plasmon resonance, and the shorter peak obtained at a lower wavelength corresponding to the axial surface plasmon resonance. The dominant longitudinal peak can be tuned by carefully controlling the GNR synthesis procedure [34]. GNR formulations, corresponding to longitudinal peak of 840 nm, were synthesized using the seed-mediated procedure. The plasmon peak as designed to overlap with the blue edge of the OCT imaging spectral band is shown in Figure 1, to provide a steep wavelength-dependent response [35]. TEM imaging of the GNRs corresponding to a longitudinal peak of 840 nm shown in Figure 1 (inset), reveals rod-shaped well-dispersed nanoparticles 45 ± 6 nm in length and 12 ± 2 nm in width.


Single step nanoplasmonic immunoassay for the measurement of protein biomarkers.

Prabhulkar S, de la Zerda A, Paranjape A, Awdeh RM - Biosensors (Basel) (2013)

Extinction spectrum of gold nanorods (GNRs) (black line) and relative intensity of (optical coherence tomography) (OCT) imaging light (red line). Inset: transmission electron microscopy (TEM) image of bare GNRs corresponding to longitudinal peak of 840 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263591&req=5

biosensors-03-00077-f001: Extinction spectrum of gold nanorods (GNRs) (black line) and relative intensity of (optical coherence tomography) (OCT) imaging light (red line). Inset: transmission electron microscopy (TEM) image of bare GNRs corresponding to longitudinal peak of 840 nm.
Mentions: GNRs were selected as the indicator label for the immunoassay due to their tunable aspect ratios and high quality factor [6,15]. The tunability of optical resonances is of crucial importance, where nanostructures have to be configured to a selected wavelength such as the central wavelength of the illumination source. The dimensions of the GNRs are closely related to their light scattering and absorbing capabilities. The working principle of OCT is related to the capture and analysis of light backscattered from sample, thus we are interested in preferentially scattering nanoparticles [12]. The extinction spectra of the GNRs is characterized by two peaks, the larger/dominant peak corresponding to the longitudinal surface plasmon resonance, and the shorter peak obtained at a lower wavelength corresponding to the axial surface plasmon resonance. The dominant longitudinal peak can be tuned by carefully controlling the GNR synthesis procedure [34]. GNR formulations, corresponding to longitudinal peak of 840 nm, were synthesized using the seed-mediated procedure. The plasmon peak as designed to overlap with the blue edge of the OCT imaging spectral band is shown in Figure 1, to provide a steep wavelength-dependent response [35]. TEM imaging of the GNRs corresponding to a longitudinal peak of 840 nm shown in Figure 1 (inset), reveals rod-shaped well-dispersed nanoparticles 45 ± 6 nm in length and 12 ± 2 nm in width.

Bottom Line: This nanoplasmonic immunoassay can act as a simple, selective, sensitive strategy for effective disease diagnosis.It offers advantages such as wide detection range, increased speed of analysis (due to fewer incubation/washing steps), and no label development as compared to traditional immunoassay techniques.Our future goal is to incorporate this detection strategy onto a microfluidic platform to be used as a point-of-care diagnostic tool.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Miami-Bascom Palmer Eye Institute, Miami, FL 33136, USA; E-Mails: sprabhulkar@med.miami.edu (S.P.); asparanjape@gmail.com (A.P.).

ABSTRACT
A nanoplasmonic biosensor for highly-sensitive, single-step detection of protein biomarkers is presented. The principle is based on the utilization of the optical scattering properties of gold nanorods (GNRs) conjugated to bio-recognition molecules. The nanoplasmonic properties of the GNRs were utilized to detect proteins using near-infrared light interferometry. We show that the antibody-conjugated GNRs can specifically bind to our model analyte, Glucose Transporter-1 (Glut-1). The signal intensity of back-scattered light from the GNRs bound after incubation, correlated well to the Glut-1 concentration as per the calibration curve. The detection range using this nanoplasmonic immunoassay ranges from 10 ng/mL to 1 ug/mL for Glut-1. The minimal detectable concentration based on the lowest discernable concentration from zero is 10 ng/mL. This nanoplasmonic immunoassay can act as a simple, selective, sensitive strategy for effective disease diagnosis. It offers advantages such as wide detection range, increased speed of analysis (due to fewer incubation/washing steps), and no label development as compared to traditional immunoassay techniques. Our future goal is to incorporate this detection strategy onto a microfluidic platform to be used as a point-of-care diagnostic tool.

No MeSH data available.


Related in: MedlinePlus