Molecular photo-thermal optical coherence phase microscopy using gold nanorods

Pai, Jing-Hong; Liu, Tianqing; Hsu, Hung-Yao; Wedding, A. B.; Thierry, Benjamin; Bagnaninchi, Pierre O.

doi:10.1039/c4ra03041a

Cited by 3 publications

(4 citation statements)

References 38 publications

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“…1 †), however, TEM fails to provide information on global distribution of NS in whole MTS. To evaluate the efficacy of our targeting, we used photothermal OCT (PTOCT) 20 as it allows intact MTS to be imaged with appropriate spatial resolution to show MTS targeting and does not require sectioning or staining. For PTOCT, nanosensors in the MTS were photothermally heated by a modulated laser (785 nm), which created a modu-lation in the phase of the OCT signal over time.…”

Section: Visualizing and Controlling 3d Nanosensor Distributionmentioning

confidence: 99%

“…The system used in this study was similar to the system used by Pai et al 20 The custom system is built around a commercial OCT engine (Callisto, Thorlabs) which consist of a spectrometer and a superluminescent laser diode (SLD) light source centred at λ o = 930 nm with a FWHM bandwidth of 90 nm, providing a resolution of 5 μm in tissue.…”

Section: Photothermal Octmentioning

confidence: 99%

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Targeted SERS nanosensors measure physicochemical gradients and free energy changes in live 3D tumor spheroids

et al. 2016

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Use of multicellular tumor spheroids (MTS) to investigate therapies has gained impetus because they have potential to mimic factors including zonation, hypoxia and drug-resistance. However, analysis remains difficult and often destroys 3D integrity. Here we report an optical technique using targeted nanosensors that allows in situ 3D mapping of redox potential gradients whilst retaining MTS morphology and function. The magnitude of the redox potential gradient can be quantified as a free energy difference (ΔG) and used as a measurement of MTS viability. We found that by delivering different doses of radiotherapy to MTS we could correlate loss of ΔG with increasing therapeutic dose. In addition, we found that resistance to drug therapy was indicated by an increase in ΔG. This robust and reproducible technique allows interrogation of an in vitro tumor-model's bioenergetic response to therapy, indicating its potential as a tool for therapy development.

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Section: Visualizing and Controlling 3d Nanosensor Distributionmentioning

confidence: 99%

Section: Photothermal Octmentioning

confidence: 99%

Targeted SERS nanosensors measure physicochemical gradients and free energy changes in live 3D tumor spheroids

et al. 2016

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“…The local geometric and refractive index changes alter the local optical path length (OPL) that can be directly detected by a phase sensitive OCT system. As a biomedical agent with great potential, GNRs have been used as contrast agents in PT-OCT for in vivo imaging and 3D imaging of tissue structure [30,33], and even for molecular imaging [34]. In these reports, however, the photothermal trapping effect of GNRs to Ti:Sa laser beams was discarded, and the photothermal trapping induced movements of GNRs in the tissue sample was ignored.…”

Section: Introductionmentioning

confidence: 99%

Photothermal optical coherence tomography for investigation and imaging photothermal trapping of gold nano-rods in clear media and biological tissue

Hu¹,

Podoleanu²,

Dobre³

2019

J. Opt.

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A quantitative spectrometer-based photothermal optical coherence tomography (PT-OCT) system is employed to investigate and image the photothermal trapping of gold nano-rods (GNRs) in clear and biological media. The PT-OCT system is calibrated through dynamic phase measurements of piezo motion with known driving parameters. We measure and compare the displacement sensitivities of the PT-OCT system at different camera exposure time settings in two configurations: with a distinct reference path; and with a common path. The displacement sensitivity of the system in the common path configuration is improved from 1.5 to 0.17 nm by performing Fourier analysis on the output phase. The minimum Ti:Sa power capable of inducing a detectable photothermal response of GNRs is measured to be 0.5 mW. This value agrees with the latest reported minimum Ti:Sa power for photothermal trapping GNRs. The PT-OCT system is used to generate en-face images of photothermal trapped GNRs in the water solution and in the biological tissue. By displaying the difference between successive en-face phase images, spatial distribution patterns of the aggregated GNRs, resulted from the photothermal trapping, are clearly outlined with great contrast. The photothermal trapping of GNRs in tissue shows a greater complexity than in the clear media. The limitation of the PT-OCT technology is discussed. The study proves the potential of PT-OCT for imaging the photothermal trapping of GNRs.

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“…Owing to this fact, conclusions regarding thermal energy dissipation in microscopic research have to be drawn based on fluorescence measurements. Recently, activity of several research groups has been concentrated on a design of a technique suitable for imaging of heat emission on a microscopic level. − In the present work, we propose an original idea of a photothermal imaging microscopy (PTIM) which can fill the gap in the arsenal of advanced techniques addressed to study molecular objects and processes associated with energy conversion and transmission.…”

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confidence: 99%

Photothermal Microscopy: Imaging of Energy Dissipation From Photosynthetic Complexes

et al. 2015

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An idea of a photothermal imaging microscopy (PTIM) is proposed, along with its realization based on a dependence of fluorescence anisotropy of dye molecules on heat emission in their nearest vicinity. Erythrosine B was selected as a fluorophore convenient to report thermal deactivation of the excited pigment-protein complex isolated from the photosynthetic apparatus of plants (LHCII), owing to the relatively large spectral gap between the fluorescence emission bands of chlorophyll a and a probe. Comparison of the simultaneously recorded images based on fluorescence lifetime of LHCII and fluorescence anisotropy of erythrosine shows a high rate of thermal energy dissipation from the aggregated forms of the complex and, possibly, thermal energy transmission along the protein supramolecular structures. Relatively high resolution of this novel microscopic technique, comparable to the fluorescence lifetime microscopy, enables its application in a nanoscale imaging and in nanothermography.

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Molecular photo-thermal optical coherence phase microscopy using gold nanorods

Abstract: A new evolution of OCT is termed molecular OCPM, which is capable of imaging the expression of molecular markers at the cellular level by using functionalized gold nanorods as imaging agents.

Cited by 3 publications

References 38 publications

Targeted SERS nanosensors measure physicochemical gradients and free energy changes in live 3D tumor spheroids

Targeted SERS nanosensors measure physicochemical gradients and free energy changes in live 3D tumor spheroids

Photothermal optical coherence tomography for investigation and imaging photothermal trapping of gold nano-rods in clear media and biological tissue

Photothermal Microscopy: Imaging of Energy Dissipation From Photosynthetic Complexes

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