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Tuning the selectivity and sensitivity of an OmpG nanopore sensor by adjusting ligand tether length.

ABSTRACT: We have previously shown that a biotin ligand tethered to the rim of an OmpG nanopore can be used to detect biotin-binding proteins. Here, we investigate the effect of the length of the polyethylene glycol tether on the nanopore's sensitivity and selectivity. When the tether length was increased from 2 to 45 ethylene repeats, sensitivity decreased substantially for a neutral protein streptavidin and slightly for a positively charged protein (avidin). In addition, we found that two distinct avidin binding conformations were possible when using a long tether. These conformations were sensitive to the salt concentration and applied voltage. Finally, a longer tether resulted in reduced sensitivity due to slower association for a monoclonal anti-biotin antibody. Our results highlight the importance of electrostatic, electroosmotic and electrophoretic forces on nanopore binding kinetics and sensor readout.

SUBMITTER: Fahie MA

PROVIDER: S-EPMC4972499 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Tuning the selectivity and sensitivity of an OmpG nanopore sensor by adjusting ligand tether length.

Fahie Monifa A MA Yang Bib B Pham Bach B Chen Min M

ACS sensors 20160330 5

We have previously shown that a biotin ligand tethered to the rim of an OmpG nanopore can be used to detect biotin-binding proteins. Here, we investigate the effect of the length of the polyethylene glycol tether on the nanopore's sensitivity and selectivity. When the tether length was increased from 2 to 45 ethylene repeats, sensitivity decreased substantially for a neutral protein streptavidin and slightly for a positively charged protein (avidin). In addition, we found that two distinct avidi ...[more]

PMID: 27500277

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