title: Comparison of the signaling and stability of electrochemical DNA sensors fabricated from 6- or 11-carbon self-assembled monolayers.
abstract: We have characterized the solution-phase and dry storage stability of electrochemical E-DNA sensors fabricated using mixed self-assembled monolayers (SAMs) composed of 6- or 11-carbon (C6 and C11, respectively) alpha,omega-thiol alcohols and the analogous C6- or C11-thiol-terminated stem-loop DNA probe. We find that the solution-phase and dry storage stability of C6-based E-DNA sensors are limited and poorly reproducible. The use of stabilizing agents bovine serum albumin plus either glucose or trehalose significantly improves the dry storage shelf life of such sensors: when using these preservatives, we observe only 7-9% sensor degradation after 1 month of storage in air at room temperature. In comparison, the stability of C11-based E-DNA sensors is significantly greater than that of the C6-based sensors; we observe only minor (5-8%) loss of signal upon storing these sensors for a week under ambient solution conditions or for more than a month in air in the presence of preservatives. Moreover, whereas the electron-transfer rate through C11 SAMs is slower than that observed for C6 SAMs, it is rapid enough to support good sensor performance. It thus appears that C11 SAMs provide a reasonable compromise between electron-transfer efficiency and sensor stability and are well suited for use in electronic DNA-sensing applications.
authors.affiliation: Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: Rebecca Y
authors.initials: RY
authors.lastname: Lai
authors.forename: Dwight S
authors.initials: DS
authors.lastname: Seferos
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Heeger
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Plaxco
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D006046:Gold / Q000737:chemistry; D008567:Membranes, Artificial; D009841:Oligonucleotides / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000438:Alcohols; D008567:Membranes, Artificial; D009841:Oligonucleotides; D013438:Sulfhydryl Compounds; D002244:Carbon; D006046:Gold; D004247:DNA