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A large field-of-view and fast scanning of photoacoustic microscopy (PAM) relatively have been difficult to obtain due to the water-drowned structure of the system for the transmission of ultrasonic signals. Researchers have widely studied the achievement of a waterproof scanner for dynamic biological applications with a high-resolution and high signal-to-noise ratio. This Letter reports a novel, to the best of our knowledge, waterproof galvanometer scanner-based PAM system with a successfully attainable ${9.0}\;{\rm mm} \times {14.5}\;{\rm mm}$9.0mm×14.5mm scan region, amplitude scan rate of 40 kHz, and spatial resolution of 4.9 µm. The in vivo characterization of a mouse brain in intact-skull microvascular visualization demonstrated its capability in biomedical imaging and is anticipated to be an effective technique for various preclinical and clinical studies.

Ultrasound and photoacoustic imaging are highly complementary modalities since both use ultrasonic detection for operation. Increasingly, photoacoustic and ultrasound have been integrated in terms of hardware instrumentation. To generate a broadly accessible dual-modality contrast agent, we generated microbubbles (a standard ultrasound contrast agent) in a solution of methylene blue (a standard photoacoustic dye). This MB2 solution was formed effectively and was optimized as a dual-modality contrast solution. As microbubble concentration increased (with methylene blue concentration constant), photoacoustic signal was attenuated in the MB2 solution. When methylene blue concentration increased (with microbubble concentration held constant), no ultrasonic interference was observed. Using an MB2 solution that strongly attenuated all photoacoustic signal, high powered ultrasound could be used to burst the microbubbles and dramatically enhance photoacoustic contrast (>800-fold increase), providing a new method for spatiotemporal control of photoacoustic signal generation.

Chronic kidney disease (CKD) affects the morphological structure and causes significant degradation in kidney function, leading to renal replacement treatment in affected individuals. Vascular rarefaction is thought to be an important factor in accelerating kidney damage in CKD patients, therefore, the assessment of renal morphology and vasculature is crucial in nephrology. The objective of this study was to evaluate the morphological and vascular changes caused by CKD in mice kidneys. In this study, dual photoacoustic microscopy (PAM) and optical coherence microscopy (OCM) oriented wide-field high-resolution imaging modalities were employed for diseased renal imaging. The unilateral ureteral obstruction (UUO) model was used to prepare renal samples with CKD, and the developed wide-field dual imaging system was used to image both control and CKD-affected kidneys for assessing vascular and morphological changes during CKD progression. The obtained results reveal a gradual alteration in vascular intensity and pelvis space with the progress of UUO disease. Furthermore, a quantitative micro-vessel analysis was performed based on the node, junction, and mesh of the vessel, which provides details on the increasing microvascular-related characteristics in the peripheral area as the disease progresses. Thus, by concurrently employing the advantages of each optical imaging technique, the proposed method of assessing the OCM-based morphological and PAM-based vascular properties of the renal sample using a wide-field multimodal imaging system can be an efficient technique for whole volume analysis without any exogenous contrast agents in kidney histopathology. [ABSTRACT FROM AUTHOR]

To identify the vascular alteration by photodynamic therapy (PDT), the utilization of high-resolution, high-speed, and wide-field photoacoustic microscopy (PAM) has gained enormous interest. The rapid changes in vasculature during PDT treatment and monitoring of tumor tissue activation in the orthotopic pancreatic cancer model have received limited attention in previous studies. Here, a fully two-axes waterproof galvanometer scanner-based photoacoustic microscopy (WGS-PAM) system was developed for in vivo monitoring of dynamic variations in micro blood vessels due to PDT in an orthotopic pancreatic cancer mouse model. The photosensitizer (PS), Chlorin e6 (Ce6), was utilized to activate antitumor reactions in response to the irradiation of a 660 nm light source. Microvasculatures of angiogenesis tissue were visualized on a 40 mm2 area using the WGS-PAM system at 30 min intervals for 3 h after the PDT treatment. The decline in vascular intensity was observed at 24.5% along with a 32.4% reduction of the vascular density at 3 h post-PDT by the analysis of PAM images. The anti-vascularization effect was also identified with fluorescent imaging. Moreover, Ce6-PDT increased apoptotic and necrotic markers while decreasing vascular endothelial growth factor (VEGF) expression in MIA PaCa-2 and BxPC-3 pancreatic cancer cell lines. The approach of the WGS-PAM system shows the potential to investigate PDT effects on the mechanism of angiographic dynamics with high-resolution wide-field imaging modalities. [ABSTRACT FROM AUTHOR]

Pores are the microscopic openings in the skin that emit oils and sweat. Pores can appear larger due to acne, sun damage, or increased sebum production, a waxy and oily substance that causes oily skin. Investigating and extracting sebum from facial pores is essential for treating skin issues as the enlargement of the pores causes higher susceptibility of the skin to microbe aggressions and inflammatory reactions. In this study, we assessed the volumetric size of pores before and after the sebum extraction using spectral domain optical coherence tomography (SD-OCT). To properly estimate the volume of the sebum before and after extraction, multiple cross-sectional OCT images were selected. The area of a single pixel was calculated from the OCT images using the scanning range. Furthermore, an algorithm was developed to use the pixel area to calculate the full volumetric size of the skin pore. This research illustrates the use of a high-resolution microscopic analysis using SD-OCT in dermatological research and can operate as a guideline for future research investigations in evaluating non-destructively wounded tissue analysis, underlying skin biochemistry, and facial statistical approaches in skin parameters for moisturizer treatment. [ABSTRACT FROM AUTHOR]

Rapid climate change has increased the incidence of various pests and diseases, and these threaten global food security. In particular, BLB (bacterial leaf blight) is caused by Xoo (Xanthomonas oryzae pv. oryzae) and its main characteristic is that the rice suddenly dries and withers. Recently, omics have been effectively used in agriculture. In particular, it is a key technology that can accurately diagnose diseases in the field. Until now, QTL (quantitative trait loci) mapping has been analyzed using only subjective phenotypic data by experts. However, in this study, diseases were accurately diagnosed using OCT (optical coherence tomography), and QTL mapping was performed using leaf thickness and leaf angles after Xoo inoculation. After Xoo inoculation of a 120 Cheongcheong/Nagdong double haploid (CNDH) population, QTL mapping was performed using the changing leaf angle, and OsWRKY34q1 was detected in RM811-RM14323 of chromosome 1. OsWRKY34q1 always had a higher expression level in the BLB-resistant population than in the susceptible population after Xoo inoculation. OsWRKY34q1 belongs to the WRKY family of genes. OsWRKY34q1 could be effectively used to develop BLB-resistant rice varieties in response to the current era of unpredictable climate change. [ABSTRACT FROM AUTHOR]

Photoacoustic imaging (PAI) is a hybrid non-invasive imaging technique used to merge high optical contrast and high acoustic resolution in deep tissue. PAI has been extensively developed by utilizing its advantages that include deep imaging depth, high resolution, and label-free imaging. As a representative implementation of PAI, photoacoustic microscopy (PAM) has been used in preclinical and clinical studies for its micron-scale spatial resolution capability with high optical absorption contrast. Several handheld and portable PAM systems have been developed that improve its applicability to several fields, making it versatile. In this study, we developed a laboratory-customized, two-axis, waterproof, galvanometer scanner-based handheld PAM (WP-GVS-HH-PAM), which provides an extended field of view (14.5 × 9 mm2) for wide-range imaging. The fully waterproof handheld probe enables free movement for imaging regardless of sample shape, and volume rate and scanning region are adjustable per experimental conditions. Results of WP-GVS-HH-PAM-based phantom and in vivo imaging of mouse tissues (ear, iris, and brain) confirm the feasibility and applicability of our system as an imaging modality for various biomedical applications. [ABSTRACT FROM AUTHOR]

• Optical coherence tomography utilization to evaluate the SLA 3D printing quality. • An image processing algorithm was developed for analyzing surface. • Spectrometer using half-order light from the HD grating was utilized. • Optical signal intensity is presented for varying printing temperatute. • Sorface roughness is presented of the 3D-printed samples. The term "additive manufacturing" refers to three-dimensional (3D) printing, a form of instant prototyping, a layered manufacturing technique that has significantly contributed to the healthcare sector. Stereolithography (SLA) is one of the most extensively utilized 3D printing technologies in dentistry which uses an ultraviolet laser along with resin to manufacture prosthetic models. Higher temperatures may cause crystallization in the interior structure and affect the roughness of the 3D denture models. Therefore, it is crucial to assess the surface roughness and inner-structure crystalization of the final product to ensure a defect-free dental prosthesis. In this study, the surface of an SLA-printed 3D denture was evaluated under various thermal conditions using a high-resolution, spectrometer-oriented, spectral domain optical coherence tomography (SD-OCT). A surface analysis algorithm was developed to analyze the inner structure of the 3D model using each pixel, and the average roughness (RA) value was calculated to measure the surface roughness. To improve the image quality, half-order light from the diffraction grating was used to enhance the spectrometer's performance allowing observation of the internal structure. After applying the surface analysis algorithm, the internal crystallization was observed at a depth of ∼ 10 µm below the sample's surface. This study demonstrates the feasibility of the OCT system along with a high-resolution spectrometer to detect structural deformation by determining the crystal structure inside the 3D sample at various printing temperatures. This research shows the potential use of a high-resolution microscopic analysis using OCT to evaluate the SLA 3D printing quality, which can serve as a guideline for future research investigations in evaluating 3D samples non-destructively. virus-transmitting mosquito specimens. [ABSTRACT FROM AUTHOR]

• Optical coherence tomography utilization to visualize internal organ structure. • An image processing algorithm was developed for quantitative assessment. • Depth enhancement utilization was evaluated. • Morphological segmentation is presented through 3D images. • Internal organ thickness and their depth position were presented. Mosquitoes transmit several fatal human diseases and constitute a global threat to the fight against infectious diseases. Thus, it is crucial to identify the diseases transmitted by mosquitoes, analyze their internal organs, investigate the life cycles of the viruses and pathogens they carry, and elucidate the anatomical changes they cause inside the host without dissecting them. Here we have demonstrated a method for label-free visualization of the internal organs of adult Anopheles , Aedes , and Culex mosquitoes using swept-source optical coherence tomography (SS-OCT). To overcome the limitation of depth-dependent signal-to-noise ratio (SNR) reduction, imaging was conducted using a dynamic rotational OCT scanner to acquire images of the top and bottom surfaces of the specimens. The internal structure and organ images of all the mosquito specimens had constant resolvability and higher SNR than in those obtained via conventional OCT. Furthermore, a depth profiling algorithm was developed to obtain quantitative information about the internal organs. Several internal organs, such as the salivary glands, heart, midgut, dorsal and ventral crop, and abdominal ganglia, were precisely identified and analyzed noninvasively using OCT. The average thicknesses of the heart, midgut, dorsal and ventral crop, and abdominal ganglia of Anopheles , Aedes, and Culex mosquitoes were 72.1, 107.3, 87.3, and 63.4 μm, respectively. This study demonstrates the applicability of OCT in entomology research for high-resolution microscopic analysis. The findings of this study can guide future studies requiring nondestructive assessment of internal organs to evaluate the morphological differences among various virus-transmitting mosquito specimens. [ABSTRACT FROM AUTHOR]

• Whole-body morphological structures of the ant were investigated using PAM. • Flattening post-pr algorithm procedure after shell removal to observe the internal structure of the ant was implemented. • Quantitative analysis for internal organs was non-invasively conducted through A-scan profiling. • The depth-resolved image analysis was performed to closely observe internal organs by applying the image post-processing algorithm. • This study demonstrates the feasibility of PAM for measuring morphological studies in the entomology field. Whole-body image analysis has been extensively applied in the field of entomology to identify differences in insect morphology. Although various conventional imaging techniques have been used for analyzing insect morphology, these often inflict damage on the sample during preparation and limitedly provide superficial information. To overcome the conventional limitations, in this study, we noninvasively observed the morphological structures of the ant Camponotus atrox , from the whole body to specific parts, over a wide scan range using optical-resolution photoacoustic microscopy (PAM). Based on the obtained photoacoustic maximum amplitude projection images, various structures of the ant, including the antenna, compound eyes, coxa, mandibles, mesonotum, propodeum, petiole, sting, and tergite, could be discerned by covering the entire ant body. In addition, we attained the morphological structures in detail by magnifying three specific parts, namely, the compound eyes, head, and thorax. Furthermore, we non-destructively analyzed the internal structure of various organs, such as the compound eyes, social stomach, and hindgut, via depth profiling of cross-sectional images. Finally, by implementing an algorithm, we visualized the depth-resolved en-face images of internal structures according to a constant depth interval. The findings established that the PAM system could identify not only each external morphological feature of the ant visible but also the sublayers of its internal structures. This study demonstrates the feasibility of PAM for contributing to performing morphological studies in entomological research. [ABSTRACT FROM AUTHOR]

• A new integrated system of surgical microscope and optical coherence tomography angiography for intraoperative applications. • Developed system simultaneously provides superficial, morphological, and blood vessel-related functional information. • Multiple information of surgical region are concurrently displayed on the ocular eyepiece by augmented reality. Intraoperative surgical microscopy integrated with optical coherence tomography (OCT) has improved the accuracy and safety of surgeries by providing a visualization of the sub-surface tissue structure. Although intraoperative OCT has resolved the conventional limitations of the surgical microscope, it is still remained to provide additional informative blood vessel-related data that is required to enhance the stability of surgery by minimizing bleeding and tissue damage. In this paper, we developed a virtual intraoperative OCT angiography integrated surgical microscope (VI-OCTA-SM) to simultaneously visualize morphological tissue structure and microvasculature data of the surgical region including tumor margin and blood vessel map. In addition, cross-sectional OCT and OCTA images and a three-dimensional maximum amplitude projection OCTA vascular map are concurrently displayed on the ocular eyepiece by augmented reality. The results of VI-OCTA-SM-based in-vivo imaging of mouse tissue (ear and brain) with different magnifications confirmed the capability of the VI-OCTA-SM to perform microvasculature imaging of small animals with an adjustable lateral resolution and scanning range according to the experimental conditions. Moreover, we successfully conducted melanoma resection as a simulated surgery following the guidance of the VI-OCTA-SM, which verified the applicability of the developed system to the surgical environment. Our proposed VI-OCTA-SM system has promising potential in various intraoperative applications including dermatological, ophthalmological, and neurological surgeries. [ABSTRACT FROM AUTHOR]