Imaging single chiral nanoparticles in turbid media using circular-polarization optical coherence microscopy.
Optical coherence tomography (OCT) is a widely used structural imaging method. However, it has limited use in molecular imaging due to the lack of an effective contrast mechanism. Gold nanoparticles have been widely used as molecular probes for optical microcopy based on Surface Plasmon Resonance (SPR). Unfortunately, the SPR enhanced backscattering from nanoparticles is still relatively weak compared with the background signal from microscopic structures in biological tissues when imaged with OCT. Consequently, it is extremely challenging to perform OCT imaging of conventional nanoparticles in thick tissues with sensitivity comparable to that of fluorescence imaging. We have discovered and demonstrated a novel approach towards remarkable contrast enhancement, which is achieved by the use of a circular-polarization optical coherence microscopy system and 3-dimensional chiral nanostructures as contrast agents. By detecting the circular intensity differential depolarization (CIDD), we successfully acquired high quality images of single chiral nanoparticles underneath a 1-mm-thick tissue -mimicking phantom.
1] Optical Bioimaging Lab, Department of Bioengineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576 [2].
Pengfei
P
Zhang
1] NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456 [2].
Kalpesh
K
Mehta
1] Optical Bioimaging Lab, Department of Bioengineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576 [2] BioSystems and Micromechanics IRG, Singapore MIT Alliance for Research and Technology, 1 Create Way, Singapore 138602.
Shakil
S
Rehman
1] Optical Bioimaging Lab, Department of Bioengineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576 [2] NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456.
Nanguang
N
Chen
D003287:Contrast Media / Q000737:chemistry; D003952:Diagnostic Imaging / Q000379:methods; D005453:Fluorescence; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D008853:Microscopy / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry; D019047:Phantoms, Imaging; D041623:Tomography, Optical Coherence / Q000379:methods*
D003287:Contrast Media; D006046:Gold