Di Kang
University of California, Santa Barbara
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Publication
Featured researches published by Di Kang.
Proceedings of the National Academy of Sciences of the United States of America | 2010
Fan Xia; Xiaolei Zuo; Renqiang Yang; Yi Xiao; Di Kang; Alexis Vallée-Bélisle; Xiong Gong; Jonathan D. Yuen; Ben B. Y. Hsu; Alan J. Heeger; Kevin W. Plaxco
We have demonstrated a novel sensing strategy employing single-stranded probe DNA, unmodified gold nanoparticles, and a positively charged, water-soluble conjugated polyelectrolyte to detect a broad range of targets including nucleic acid (DNA) sequences, proteins, small molecules, and inorganic ions. This nearly “universal” biosensor approach is based on the observation that, while the conjugated polyelectrolyte specifically inhibits the ability of single-stranded DNA to prevent the aggregation of gold-nanoparticles, no such inhibition is observed with double-stranded or otherwise “folded” DNA structures. Colorimetric assays employing this mechanism for the detection of hybridization are sensitive and convenient—picomolar concentrations of target DNA are readily detected with the naked eye, and the sensor works even when challenged with complex sample matrices such as blood serum. Likewise, by employing the binding-induced folding or association of aptamers we have generalized the approach to the specific and convenient detection of proteins, small molecules, and inorganic ions. Finally, this new biosensor approach is quite straightforward and can be completed in minutes without significant equipment or training overhead.
Analytical Chemistry | 2009
Di Kang; Xiaolei Zuo; Renqiang Yang; Fan Xia; Kevin W. Plaxco; Ryan J. White
Many electrochemical biosensor approaches developed in recent years utilize redox-labeled (most commonly methylene blue or ferrocene) oligonucleotide probes site-specifically attached to an interrogating electrode. Sensors in this class have been reported that employ a range of probe architectures, including single- and double-stranded DNA, more complex DNA structures, DNA and RNA aptamers, and, most recently, DNA-small molecule chimeras. Signaling in this class of sensors is generally predicated on binding-induced changes in the efficiency with which the covalently attached redox label transfers electrons with the interrogating electrode. Here we have investigated how the properties of the redox tag affect the performance of such sensors. Specifically, we compare the differences in signaling and stability of electrochemical DNA sensors (E-DNA sensors) fabricated using either ferrocene or methylene blue as the signaling redox moiety. We find that while both tags support efficient E-DNA signaling, ferrocene produces slightly improved signal gain and target affinity. These small advantages, however, come at a potentially significant price: the ferrocene-based sensors are far less stable than their methylene blue counterparts, particularly with regards to stability to long-term storage, repeated electrochemical interrogations, repeated sensing/regeneration iterations, and employment in complex sample matrices such as blood serum.
Angewandte Chemie | 2012
Di Kang; Alexis Vallée-Bélisle; Alessandro Porchetta; Kevin W. Plaxco; Francesco Ricci
Here we demonstrate two convenient methods to extend and narrow the useful dynamic range of a model electrochemical DNA sensor. We did so by combining DNA probes of different target affinities but with similar specificity on the same electrode. We were able to achieve an extended dynamic response spanning 3 orders of magnitude in target concentration. Using a different strategy we have also narrowed the useful dynamic range of an E-DNA sensor to only an 8-fold range of target concentrations.
Journal of the American Chemical Society | 2010
Fan Xia; Ryan J. White; Xiaolei Zuo; Adriana S. Patterson; Yi Xiao; Di Kang; Xiong Gong; Kevin W. Plaxco; Alan J. Heeger
Journal of the American Chemical Society | 2010
Fan Xia; Xiaolei Zuo; Renqiang Yang; Ryan J. White; Yi Xiao; Di Kang; Xiong Gong; Arica A. Lubin; Alexis Vallée-Bélisle; Jonathan D. Yuen; Ben Y. B. Hsu; Kevin W. Plaxco
Npg Asia Materials | 2012
Di Kang; Ryan J. White; Fan Xia; Xiaolei Zuo; Alexis Vallée-Bélisle; Kevin W. Plaxco
Journal of the American Chemical Society | 2010
Fan Xia; Xiaolei Zuo; Renqiang Yang; Yi Xiao; Di Kang; Alexis Vallée-Bélisle; Xiong Gong; Alan J. Heeger; Kevin W. Plaxco
Journal of the American Chemical Society | 2016
Hui Li; Netzahualcóyotl Arroyo-Currás; Di Kang; Francesco Ricci; Kevin W. Plaxco
Analytical Chemistry | 2016
Di Kang; Francesco Ricci; Ryan J. White; Kevin W. Plaxco
Journal of the American Chemical Society | 2017
Di Kang; Sheng Sun; Martin Kurnik; Demosthenes Morales; Frederick W. Dahlquist; Kevin W. Plaxco