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A PDMS-Based 2-Axis Waterproof Scanner for Photoacoustic Microscopy.

Kim JY, Lee C, Park K, Lim G, Kim C - Sensors (Basel) (2015)

Bottom Line: Finally, OR-PAM with high SNRs is demonstrated using the fabricated scanner, and the PA images of micro-patterned samples and microvasculatures of a mouse ear are successfully obtained with high-resolution and wide-field of view.OR-PAM equipped with the 2-axis PDMS based waterproof scanner has lateral and axial resolutions of 3.6 μm and 26 μm, respectively.This compact OR-PAM system could potentially and widely be used in preclinical and clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea. ronsan@postech.ac.kr.

ABSTRACT
Optical-resolution photoacoustic microscopy (OR-PAM) is an imaging tool to provide in vivo optically sensitive images in biomedical research. To achieve a small size, fast imaging speed, wide scan range, and high signal-to-noise ratios (SNRs) in a water environment, we introduce a polydimethylsiloxane (PDMS)-based 2-axis scanner for a flexible and waterproof structure. The design, theoretical background, fabrication process and performance of the scanner are explained in details. The designed and fabricated scanner has dimensions of 15 × 15 × 15 mm along the X, Y and Z axes, respectively. The characteristics of the scanner are tested under DC and AC conditions. By pairing with electromagnetic forces, the maximum scanning angles in air and water are 18° and 13° along the X and Y axes, respectively. The measured resonance frequencies in air and water are 60 and 45 Hz along the X axis and 45 and 30 Hz along the Y axis, respectively. Finally, OR-PAM with high SNRs is demonstrated using the fabricated scanner, and the PA images of micro-patterned samples and microvasculatures of a mouse ear are successfully obtained with high-resolution and wide-field of view. OR-PAM equipped with the 2-axis PDMS based waterproof scanner has lateral and axial resolutions of 3.6 μm and 26 μm, respectively. This compact OR-PAM system could potentially and widely be used in preclinical and clinical applications.

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In vitro PA imaging of gold micro-patterns using the 2A-PDMS-WP-OR-PAM. (a) Photograph of gold micro-patterns; (b) PA maximum amplitude projection image of the red boxed region of (a); (c) PA amplitude profile across the a-a′ line of (b) and fitted edge spread function (ESF) and line spread function (LSF). Full width at half maximum (FWHM) in the plot means a lateral resolution of the system.
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sensors-15-09815-f006: In vitro PA imaging of gold micro-patterns using the 2A-PDMS-WP-OR-PAM. (a) Photograph of gold micro-patterns; (b) PA maximum amplitude projection image of the red boxed region of (a); (c) PA amplitude profile across the a-a′ line of (b) and fitted edge spread function (ESF) and line spread function (LSF). Full width at half maximum (FWHM) in the plot means a lateral resolution of the system.

Mentions: To verify the performance of the 2A-PDMS-WP-OR-PAM system, a gold micro-patterned sample with a thickness of 200 nm on a glass plate (Figure 6a) is photoacoustically imaged (Figure 6b) in vitro. The gold micro-patterns are prepared by a conventional MEMS process, which includes a photolithography for micro-patterning and etching the gold film on a glass substrate. The smallest width of the gold micro-patterns is 20 μm on the center. The scanning range is 2 mm × 1.8 mm along the X and Y axes, respectively. As shown in Figure 6b, the gold micro-patterns are clearly visualized in the PA image. To quantify the lateral resolution, the PA amplitude profile along the a-a′ line is plotted in Figure 6c. The line spread function (LSF) is derived from the fitting curve of the edge spread function (ESF) in the range of from 0 to 18 μm. The calculated full width at half maximum (FWHM) of the LSF, a lateral resolution of the system, is 3.6 μm, and the value well matches with the theoretical estimation (i.e., 3.4 μm). The axial resolution is determined by the one-way acoustic bandwidth, approximately 26 μm [15].


A PDMS-Based 2-Axis Waterproof Scanner for Photoacoustic Microscopy.

Kim JY, Lee C, Park K, Lim G, Kim C - Sensors (Basel) (2015)

In vitro PA imaging of gold micro-patterns using the 2A-PDMS-WP-OR-PAM. (a) Photograph of gold micro-patterns; (b) PA maximum amplitude projection image of the red boxed region of (a); (c) PA amplitude profile across the a-a′ line of (b) and fitted edge spread function (ESF) and line spread function (LSF). Full width at half maximum (FWHM) in the plot means a lateral resolution of the system.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481887&req=5

sensors-15-09815-f006: In vitro PA imaging of gold micro-patterns using the 2A-PDMS-WP-OR-PAM. (a) Photograph of gold micro-patterns; (b) PA maximum amplitude projection image of the red boxed region of (a); (c) PA amplitude profile across the a-a′ line of (b) and fitted edge spread function (ESF) and line spread function (LSF). Full width at half maximum (FWHM) in the plot means a lateral resolution of the system.
Mentions: To verify the performance of the 2A-PDMS-WP-OR-PAM system, a gold micro-patterned sample with a thickness of 200 nm on a glass plate (Figure 6a) is photoacoustically imaged (Figure 6b) in vitro. The gold micro-patterns are prepared by a conventional MEMS process, which includes a photolithography for micro-patterning and etching the gold film on a glass substrate. The smallest width of the gold micro-patterns is 20 μm on the center. The scanning range is 2 mm × 1.8 mm along the X and Y axes, respectively. As shown in Figure 6b, the gold micro-patterns are clearly visualized in the PA image. To quantify the lateral resolution, the PA amplitude profile along the a-a′ line is plotted in Figure 6c. The line spread function (LSF) is derived from the fitting curve of the edge spread function (ESF) in the range of from 0 to 18 μm. The calculated full width at half maximum (FWHM) of the LSF, a lateral resolution of the system, is 3.6 μm, and the value well matches with the theoretical estimation (i.e., 3.4 μm). The axial resolution is determined by the one-way acoustic bandwidth, approximately 26 μm [15].

Bottom Line: Finally, OR-PAM with high SNRs is demonstrated using the fabricated scanner, and the PA images of micro-patterned samples and microvasculatures of a mouse ear are successfully obtained with high-resolution and wide-field of view.OR-PAM equipped with the 2-axis PDMS based waterproof scanner has lateral and axial resolutions of 3.6 μm and 26 μm, respectively.This compact OR-PAM system could potentially and widely be used in preclinical and clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea. ronsan@postech.ac.kr.

ABSTRACT
Optical-resolution photoacoustic microscopy (OR-PAM) is an imaging tool to provide in vivo optically sensitive images in biomedical research. To achieve a small size, fast imaging speed, wide scan range, and high signal-to-noise ratios (SNRs) in a water environment, we introduce a polydimethylsiloxane (PDMS)-based 2-axis scanner for a flexible and waterproof structure. The design, theoretical background, fabrication process and performance of the scanner are explained in details. The designed and fabricated scanner has dimensions of 15 × 15 × 15 mm along the X, Y and Z axes, respectively. The characteristics of the scanner are tested under DC and AC conditions. By pairing with electromagnetic forces, the maximum scanning angles in air and water are 18° and 13° along the X and Y axes, respectively. The measured resonance frequencies in air and water are 60 and 45 Hz along the X axis and 45 and 30 Hz along the Y axis, respectively. Finally, OR-PAM with high SNRs is demonstrated using the fabricated scanner, and the PA images of micro-patterned samples and microvasculatures of a mouse ear are successfully obtained with high-resolution and wide-field of view. OR-PAM equipped with the 2-axis PDMS based waterproof scanner has lateral and axial resolutions of 3.6 μm and 26 μm, respectively. This compact OR-PAM system could potentially and widely be used in preclinical and clinical applications.

Show MeSH