Colorimetric Detection with Aptamer-Gold Nanoparticle Conjugates: Effect of Aptamer Length on Response
Interim rept. Feb 2008-Sep 2011
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN PERFORMANCE WING (711TH) HUMAN EFFECTIVENESS DIRECTORATE
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A riboflavin binding aptamer RBA was used in combination with gold nanoparticles AuNPs to detect riboflavin in vitro. The RBA-AuNPs responded colorimetrically to the presence of riboflavin and this response could be followed by the naked eye. We used this system as a model to study how modifications on the aptamer sequence affect the response of the aptamer-AuNP conjugates Apt-AuNPs to their target. To mimic primers and other sequence modifications typically used in aptamer work, the RBA was extended by adding random bases to its 5 end and the response of these Apt-AuNPs was evaluated. These extra bases were designed to avoid interactions with the RBA binding site. We observed that the length of the aptamer significantly affected the Apt-AuNPs stability and the magnitude of the detection response to riboflavin. The addition of thymine nucleotides instead of random tails to the RBA showed that the effects observed were not specific to the sequence used but rather general. This work shows that modifications of the aptamer sequence provide a means to improve the Apt-AuNPs sensing response.