Our group is currently studying organic photovoltaics (polymer solar cells), quantum dots, and plasmonics using scanning probe microscopy, optical spectroscopy, single-molecule techniques, and Dip-Pen Nanolithography (DPN). We have invented techniques such as fast time-resolved electrostatic force microscopy (trEFM) and developed photoconductive atomic force microscopy (pcAFM). 1

Brief Summary Photo-induced melting properties of DNA strands conjugated to Au particles. Detection of DNA defect by using LSPRs. 2

Introduction Mirkin et al. (1996. Nature), for the first time, demonstrated assembling gold nanoparticles intomacroscopic materials. applying to biodiagnostic systems Elghanian et al., 1997. Science (in Chem. Rev.) 3

Purpose Method Realizing a stimulus responsive control by light Asanuma et al., 1999. Angew. Chem. 4

Results colorless aggregate 5

Control experiments not dehybridize 6

Phohtoswitchable DNA-nanoparticle conjugates also enable a unique new form of DNA-hybridization stringency. Before suggestion•••••• Basic investigation Nearly linear for small aggregation 7

Suggestion 8

Detection of single-mismatched base in a DNA strand 9

Single-base-mismatched DNAs dehybridize by UV light irradiation. 10

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