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Optimizing Nanoplasmonic Biosensor Sensitivity with Orientated Single Domain Antibodies.

Raphael MP, Christodoulides JA, Byers JM, Anderson GP, Liu JL, Turner KB, Goldman ER, Delehanty JB - Plasmonics (2015)

Bottom Line: We demonstrate that orientated single domain antibodies (sdAb) can optimize nanoplasmonic sensitivity by comparing three anti-ricin sdAb constructs to biotin-neutravidin, a model system for small and highly orientated ligand studies.LSPR imaging of electrostatically orientated sdAb exhibited a ricin sensitivity equivalent to that of the biotinylated LSPR biosensors for neutravidin.These results, combined with the facts that sdAb are highly stable and readily produced in bacteria and yeast, build a compelling case for the increased utilization of sdAbs in nanoplasmonic applications.

View Article: PubMed Central - PubMed

Affiliation: Bioelectronics and Sensing, Code 6363, Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 USA.

ABSTRACT

Localized surface plasmon resonance (LSPR) spectroscopy and imaging are emerging biosensor technologies which tout label-free biomolecule detection at the nanoscale and ease of integration with standard microscopy setups. The applicability of these techniques can be limited by the restrictions that surface-conjugated ligands must be both sufficiently small and orientated to meet analyte sensitivity requirements. We demonstrate that orientated single domain antibodies (sdAb) can optimize nanoplasmonic sensitivity by comparing three anti-ricin sdAb constructs to biotin-neutravidin, a model system for small and highly orientated ligand studies. LSPR imaging of electrostatically orientated sdAb exhibited a ricin sensitivity equivalent to that of the biotinylated LSPR biosensors for neutravidin. These results, combined with the facts that sdAb are highly stable and readily produced in bacteria and yeast, build a compelling case for the increased utilization of sdAbs in nanoplasmonic applications.

No MeSH data available.


Ricin saturation activity versus ligand surface density for C8-zip and C8. Ligand surface density was calculated assuming a sensor calibration of 1 RU = 1 pg/mm2. The ricin concentration was 100 nM for all experiments
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Fig3: Ricin saturation activity versus ligand surface density for C8-zip and C8. Ligand surface density was calculated assuming a sensor calibration of 1 RU = 1 pg/mm2. The ricin concentration was 100 nM for all experiments

Mentions: To properly isolate the effect of orientation on A, care must be taken to work in the dilute ligand limit in order to minimize steric hindrance effects. If analyte molecules can repel one another at the surface, the result is a reduced activity value unrelated to ligand orientation. Figure 3 compares the activity of C8-zip to C8 for a range of surface ligand densities by exposing the surface to ligand concentrations of 0.25 to 10 μg/mL for 300 s. The ligand surface density was calculated assuming a sensor calibration of 1 RU = 1 pg/mm2 [35]. At higher surface densities, the activity values of the two ligands converge as expected for a surface dominated by steric hindrance. As the surface concentration is reduced, both exhibit marked increases with maximum C8-zip and C8 activities of 65 and 36 %, respectively. The results indicate that the positively charged tail of the C8-zip improved surface orientation and are consistent with the enhanced sensitivity measured in Fig. 2. We also observed improved sensitivity for the orientated sdAb when using SPR GLC sensor chips, designed by Bio-Rad for general amine coupling via a compact polymer layer with a binding capacity of approximately one protein monolayer (Supplementary Material).Fig. 3


Optimizing Nanoplasmonic Biosensor Sensitivity with Orientated Single Domain Antibodies.

Raphael MP, Christodoulides JA, Byers JM, Anderson GP, Liu JL, Turner KB, Goldman ER, Delehanty JB - Plasmonics (2015)

Ricin saturation activity versus ligand surface density for C8-zip and C8. Ligand surface density was calculated assuming a sensor calibration of 1 RU = 1 pg/mm2. The ricin concentration was 100 nM for all experiments
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4644190&req=5

Fig3: Ricin saturation activity versus ligand surface density for C8-zip and C8. Ligand surface density was calculated assuming a sensor calibration of 1 RU = 1 pg/mm2. The ricin concentration was 100 nM for all experiments
Mentions: To properly isolate the effect of orientation on A, care must be taken to work in the dilute ligand limit in order to minimize steric hindrance effects. If analyte molecules can repel one another at the surface, the result is a reduced activity value unrelated to ligand orientation. Figure 3 compares the activity of C8-zip to C8 for a range of surface ligand densities by exposing the surface to ligand concentrations of 0.25 to 10 μg/mL for 300 s. The ligand surface density was calculated assuming a sensor calibration of 1 RU = 1 pg/mm2 [35]. At higher surface densities, the activity values of the two ligands converge as expected for a surface dominated by steric hindrance. As the surface concentration is reduced, both exhibit marked increases with maximum C8-zip and C8 activities of 65 and 36 %, respectively. The results indicate that the positively charged tail of the C8-zip improved surface orientation and are consistent with the enhanced sensitivity measured in Fig. 2. We also observed improved sensitivity for the orientated sdAb when using SPR GLC sensor chips, designed by Bio-Rad for general amine coupling via a compact polymer layer with a binding capacity of approximately one protein monolayer (Supplementary Material).Fig. 3

Bottom Line: We demonstrate that orientated single domain antibodies (sdAb) can optimize nanoplasmonic sensitivity by comparing three anti-ricin sdAb constructs to biotin-neutravidin, a model system for small and highly orientated ligand studies.LSPR imaging of electrostatically orientated sdAb exhibited a ricin sensitivity equivalent to that of the biotinylated LSPR biosensors for neutravidin.These results, combined with the facts that sdAb are highly stable and readily produced in bacteria and yeast, build a compelling case for the increased utilization of sdAbs in nanoplasmonic applications.

View Article: PubMed Central - PubMed

Affiliation: Bioelectronics and Sensing, Code 6363, Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 USA.

ABSTRACT

Localized surface plasmon resonance (LSPR) spectroscopy and imaging are emerging biosensor technologies which tout label-free biomolecule detection at the nanoscale and ease of integration with standard microscopy setups. The applicability of these techniques can be limited by the restrictions that surface-conjugated ligands must be both sufficiently small and orientated to meet analyte sensitivity requirements. We demonstrate that orientated single domain antibodies (sdAb) can optimize nanoplasmonic sensitivity by comparing three anti-ricin sdAb constructs to biotin-neutravidin, a model system for small and highly orientated ligand studies. LSPR imaging of electrostatically orientated sdAb exhibited a ricin sensitivity equivalent to that of the biotinylated LSPR biosensors for neutravidin. These results, combined with the facts that sdAb are highly stable and readily produced in bacteria and yeast, build a compelling case for the increased utilization of sdAbs in nanoplasmonic applications.

No MeSH data available.