Stacked Gold Nanodisks for Bimodal Photoacoustic and Optical Coherence Imaging.

Herein, we report on biological imaging nanoprobes: physically synthesized gold nanodisks that have inherent optical advantages-a wide range of resonant wavelengths, tunable ratio of light absorption-to-scattering, and responsiveness to random incident light-due to their two-dimensional circular nanostructure. Based on our proposed physical synthesis where gold is vacuum deposited onto a prepatterned polymer template and released from the substrate in the form of a nanodisk, monodisperse two-dimensional gold nanodisks were prepared with independent control of their diameter and thickness. The optical benefits of the Au nanodisk were successfully demonstrated by the measurement of light absorbance of the nanodisks and the application of stacked nanodisks, where a smaller sized Au nanodisk was laid atop a larger nanodisk, as bimodal contrast agents for photoacoustic microscopy and optical coherence tomography.