The study presents a LED-based optoacoustic system for estimating relative absorbers’ concentration in ink - gelatin phantoms. Results support that LED sources present high potential for the development of low-cost optoacoustic spectroscopy systems.
We demonstrate the application of an extended field of view microscope, combining photoacoustic and fluorescence label-free contrast modalities, for the ex vivo investigation of ocular tissues including the ciliary muscle in healthy rabbit eyes and surgical biopsies of benign nevi removed from human eyes. In the case of ciliary muscle samples, the intrinsic photoacoustic and the glutaraldehyde-induced autofluorescence signals were observed to be spatially complementary, offering specific and high resolution morphological information as regards to Pars plana and Pars plicata ciliary body portions, iris, and zonule fiber strands. On the other hand, the biopsy samples presented a remarkable spatial overlap of the two signals in the nevus region, indicating a positive correlation between them. The bimodal microscopy approach presented in this work, has the potential to contribute in the understanding of the physiological function of the eye involving the detailed study of the ocular accommodation system and the elucidation of ageing effects such as presbyopia. Finally, the proposed hybrid diagnostic approach could be employed for the differentiation between benign and malignant intraocular tumors of the uvea in surgical biopsies, simplifying the relevant procedures for this purpose.
We present a multi-scale imaging system that integrates five optoacoustic and multi-photon modalities into the same device. The hybrid microscope offers a unique zoom-in ability by allowing for optoacoustic microscopy and mesoscopy scans of the sample within the same imaging framework. Furthermore, by combining several label-free modalities, we are able to visualize a broad range of anatomical features, taking advantage of their complementary contrast mechanisms. We characterize the spatial resolution and relative orientation of the different sub-modalities and demonstrate the system’s performance by the imaging of several model organisms ex vivo. The presented ability to dynamically vary scanning volume and resolution together with its multi-contrast and label-free imaging capabilities make the hybrid microscope a promising tool for comprehensive biological imaging.
Many biological applications require a simultaneous observation of different anatomical features. However, unless potentially harmful staining of the specimens is employed, individual microscopy techniques do generally not provide multi-contrast capabilities. We present a hybrid microscope integrating optoacoustic microscopy and multiphoton microscopy, including second-harmonic generation, into a single device. This combined multiphoton and optoacoustic microscope (MPOM) offers visualization of a broad range of structures by employing different contrast mechanisms and at the same time enables pure label-free imaging of biological systems. We investigate the relative performance of the two microscopy modalities and demonstrate their multi-contrast abilities through the label-free imaging of a zebrafish larva ex vivo, simultaneously visualizing muscles and pigments. This hybrid microscopy application bears great potential for developmental biology studies, enabling more comprehensive information to be obtained from biological specimens without the necessity of staining.
KEYWORDS: Microscopy, Harmonic generation, In vivo imaging, Signal detection, Data acquisition, Diagnostics, Video, Second-harmonic generation, Femtosecond phenomena, Glasses
In this study, we demonstrate the potential of employing third harmonic generation (THG) imaging microscopy measurements for cell tracking studies in live Caenorhabditis elegans (C. elegans) embryos. A 1028-nm femtosecond laser was used for the excitation of unstained C. elegans samples. Different C. elegans embryonic stages (from two-cell to threefold) were imaged. Live biological specimens were irradiated for prolonged periods of time (up to 7 h), testifying to the nondestructive nature of this nonlinear imaging technique. Thus, THG image contrast modality is a powerful diagnostic tool for probing in vivo cell division during early embryogenesis.
A critical challenge for the broader implementation of laser cleaning interventions in
modern paintings is the assessment of the extent of any photochemical or structural
modifications induced in the original substrate following laser irradiation. For this reason, we
investigate several polymeric materials (PMMA, Paraloid B72) doped with aromatic
photosensitisers (PhenI, POPOP) of known photochemistry, coated with uniform layers of
acrylics of different thicknesses to simulate real case scenarios. Following laser irradiation, a
variety of spectroscopic techniques LIF, MPEF are employed for the in depth monitoring of
any photochemical and structural modifications induced in the bulk material.
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