Notice of Retraction A Preliminary Investigation on Microrheological Responses of Short ssDNA in Brownian Motion

Microrheological measurements were made to characterize the viscoelastic behavior of short single-stranded DNA (ssDNA) at room temperature using video particle tracking method. The linear shear moduli which consist of the elastic storage modulus (G') and viscous loss modulus (G') of ssDNA was obtained. The data show that when the frequency is relatively low( ;10 Hz), G' rise abruptly and become comparable to G', showing an obvious behavior of viscoelasticity. The microrheological responses of short ssDNA seem to be rather different from that of double-stranded DNA (dsDNA) reported in literatures. We suggest that the frequency-dependent microrheological responses of short ssDNA perhaps implicate some novel mechanical property of ssDNA presumable at nanoscale.