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32 results on '"Canoura, Juan"'

4. Exploring the Landscape of Aptamers: From Cross-Reactive to Selective to Specific, High-Affinity Receptors for Cocaine

Author

Yang, Kyungae, primary, Alkhamis, Obtin, additional, Canoura, Juan, additional, Bryant, Alexandra, additional, Gong, Edward M., additional, Barbu, Mihaela, additional, Taylor, Steven, additional, Nikic, Dragan, additional, Banerjee, Saswata, additional, Xiao, Yi, additional, Stojanovic, Milan N., additional, and Landry, Donald W., additional

Published
2024
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5. Rapid Nuclease-Assisted Selection of High-Affinity Small-Molecule Aptamers

Author

Wang, Linlin, Alkhamis, Obtin, Canoura, Juan, Yu, Haixiang, and Xiao, Yi

Abstract

Aptamers are nucleic acid bioreceptors that have been widely utilized for a variety of biosensing applications, including in vivodetection methods that would not be possible with antibody-based systems. However, it remains challenging to generate high-quality aptamers for small molecule targets, particularly for use under physiological conditions. We present a highly effective aptamer selection technology for small-molecule targets that utilizes the nuclease EcoRI to remove nonspecific or weakly binding sequences in solution phase, rapidly enriching high-affinity target binders within just a few rounds of selection. As proof-of-concept, we used our nuclease-assisted SELEX (NA-SELEX) method to isolate aptamers for a synthetic cannabinoid, AB-FUBINACA. Within five rounds, we identified two highly specific aptamers that exhibit nanomolar affinity at physiological temperature. We also demonstrate the robustness and reproducibility of NA-SELEX by performing the same selection experiment with fresh reagents and libraries, obtaining the same two aptamers as well as two other high-quality aptamer candidates. Finally, we compare NA-SELEX against a conventional library-immobilized SELEX screen for AB-FUBINACA using the same screening conditions, identifying aptamers with 25–100-fold weaker affinity after 11 rounds of selection. NA-SELEX therefore could be an effective selection method for the isolation of high-quality aptamers for small-molecule targets.

Published
2024
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10. High-Affinity Aptamers for In Vitroand In VivoCocaine Sensing

Author

Alkhamis, Obtin, Canoura, Juan, Wu, Yuyang, Emmons, Nicole A., Wang, Yuting, Honeywell, Kevin M., Plaxco, Kevin W., Kippin, Tod E., and Xiao, Yi

Abstract

The ability to quantify cocaine in biological fluids is crucial for both the diagnosis of intoxication and overdose in the clinic as well as investigation of the drug’s pharmacological and toxicological effects in the laboratory. To this end, we have performed high-stringency in vitroselection to generate DNA aptamers that bind cocaine with nanomolar affinity and clinically relevant specificity, thus representing a dramatic improvement over the current-generation, micromolar-affinity, low-specificity cocaine aptamers. Using these novel aptamers, we then developed two sensors for cocaine detection. The first, an in vitrofluorescent sensor, successfully detects cocaine at clinically relevant levels in 50% human serum without responding significantly to other drugs of abuse, endogenous substances, or a diverse range of therapeutic agents. The second, an electrochemical aptamer-based sensor, supports the real-time, seconds-resolved measurement of cocaine concentrations in vivoin the circulation of live animals. We believe the aptamers and sensors developed here could prove valuable for both point-of-care and on-site clinical cocaine detection as well as fundamental studies of cocaine neuropharmacology.

Published
2024
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20. DNA Aptamer–Cyanine Complexes as Generic Colorimetric Small‐Molecule Sensors.

Author

Alkhamis, Obtin, Canoura, Juan, Bukhryakov, Konstantin V., Tarifa, Anamary, DeCaprio, Anthony P., and Xiao, Yi

Subjects
*APTAMERS, *DNA, *DETECTORS, *CYANINES
Abstract

Aptamers are promising biorecognition elements for sensors. However, aptamer‐based assays often lack the requisite levels of sensitivity and/or selectivity because they typically employ structure‐switching aptamers with attenuated affinity and/or utilize reporters that require aptamer labeling or which are susceptible to false positives. Dye‐displacement assays offer a label‐free, sensitive means for overcoming these issues, wherein target binding liberates a dye that is complexed with the aptamer, producing an optical readout. However, broad utilization of these assays has been limited. Here, we demonstrate a rational approach to develop colorimetric cyanine dye‐displacement assays that can be broadly applied to DNA aptamers regardless of their structure, sequence, affinity, or the physicochemical properties of their targets. Our approach should accelerate the development of mix‐and‐measure assays that could be applied for diverse analytical applications. [ABSTRACT FROM AUTHOR]

Published
2022
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