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Updated: May 25, 2026
Phthalic Acid Ester-Binding DNA Aptamer Selection, Characterization, and Application to an Electrochemical Aptasensor
Published on: March 21, 2018
Electrochemical sensing of aptamer-facilitated virus immunoshielding
Mahmoud Labib1, Anna S Zamay, Darija Muharemagic
1Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
Abstract:
Oncolytic viruses (OVs) are promising therapeutics that selectively replicate in and kill tumor cells. However, repetitive administration of OVs provokes the generation of neutralizing antibodies (nAbs) that can diminish their anticancer effects. In this work, we selected DNA aptamers against an oncolytic virus, vesicular stomatitis virus (VSV), to protect it from nAbs. A label-free electrochemical aptasensor was used to evaluate the degree of protection (DoP). The aptasensor was fabricated by self-assembling a hybrid of a thiolated ssDNA primer and a VSV-specific aptamer. Electrochemical impedance spectroscopy was employed to quantitate VSV in the range of 800-2200 PFU and a detection limit of 600 PFU. The aptasensor was also utilized for evaluating binding affinities between VSV and aptamer pools/clones. An electrochemical displacement assay was performed in the presence of nAbs and DoP values were calculated for several VSV-aptamer pools/clones. A parallel flow cytometric analysis confirmed the electrochemical results. Finally, four VSV-specific aptamer clones, ZMYK-20, ZMYK-22, ZMYK-23, and ZMYK-28, showed the highest protective properties with dissociation constants of 17, 8, 20, and 13 nM, respectively. Another four sequences, ZMYK-1, -21, -25, and -29, exhibited high affinities to VSV without protecting it from nAbs and can be further utilized in sandwich assays. Thus, ZMYK-22, -23, and -28 have the potential to allow efficient delivery of VSV through the bloodstream without compromising the patient's immune system.
Insights
DNA aptamers were developed to protect oncolytic viruses, like vesicular stomatitis virus (VSV), from neutralizing antibodies (nAbs). This protects the virus
Area of Science:
- Biotechnology
- Nanotechnology
- Virology
Background:
- Oncolytic viruses (OVs) show promise for cancer therapy by selectively targeting tumor cells.
- Neutralizing antibodies (nAbs) generated against OVs can limit their therapeutic efficacy upon repeated administration.
- Developing strategies to overcome nAb-mediated neutralization is crucial for enhancing OV treatment outcomes.
Purpose of the Study:
- To select DNA aptamers that can protect the oncolytic virus vesicular stomatitis virus (VSV) from nAbs.
- To develop and validate a label-free electrochemical aptasensor for evaluating the degree of protection (DoP) offered by aptamers.
- To identify specific VSV-aptamer clones with protective properties for potential therapeutic applications.
Main Methods:
- Fabrication of a label-free electrochemical aptasensor using a hybrid of a thiolated ssDNA primer and VSV-specific aptamers.
- Quantification of VSV using electrochemical impedance spectroscopy with a detection limit of 600 PFU.
- Evaluation of binding affinities and protection against nAbs using electrochemical displacement assays and parallel flow cytometry.
Main Results:
- The aptasensor successfully quantified VSV and evaluated binding affinities between VSV and aptamer pools/clones.
- Four VSV-specific aptamer clones (ZMYK-20, -22, -23, -28) demonstrated significant protective properties against nAbs, with dissociation constants in the nanomolar range.
- Four other aptamer clones (ZMYK-1, -21, -25, -29) showed high VSV affinity but lacked protective capabilities, suitable for sandwich assays.
Conclusions:
- Selected VSV-specific aptamer clones, particularly ZMYK-22, -23, and -28, can protect VSV from nAbs.
- These protective aptamers hold potential for enabling efficient VSV delivery via bloodstream without immune compromise.
- The developed electrochemical aptasensor is a viable tool for evaluating aptamer protection and affinity for OV therapeutics.
