Recent Posts

Multifunctional PtCuTe Nanosheets with Strong ROS Scavenging and ROS-Independent Antibacterial Properties Promote Diabetic Wound Healing

Author(s): Yaru Guo, Shuai Ding, Changshuai Shang, Chenguang Zhang, Menggang Li, Qinghua Zhang, Lin Gu, Boon Chin Heng, Shihan Zhang, Feng Mei, Ying Huang, Xuehui Zhang, Mingming Xu, Jiuhui Jiang, Shaojun Guo, Xuliang Deng, Lili Chen

Abstract

Nanozymes, as one of the most efficient reactive oxygen species (ROS)-scavenging biomaterials, are receiving wide attention in promoting diabetic wound healing. Despite recent attempts at improving the catalytic efficiency of Pt-based nanozymes (e.g., PtCu, one of the best systems), they still display quite limited ROS scavenging capacity and ROS-dependent antibacterial effects on bacteria or immunocytes, which leads to uncontrolled and poor diabetic wound healing. Hence, a new class of multifunctional PtCuTe nanosheets with excellent catalytic, ROS-independent antibacterial, proangiogenic, anti-inflammatory, and immuno-modulatory properties for boosting the diabetic wound healing, is reported. The PtCuTe nanosheets show stronger ROS scavenging capacity and better antibacterial effects than PtCu. It is also revealed that the PtCuTe can enhance vascular tube formation, stimulate macrophage polarization toward the M2 phenotype and improve fibroblast mobility, outperforming conventional PtCu. Moreover, PtCuTe promotes crosstalk between different cell types to form a positive feedback loop. Consequently, PtCuTe stimulates a proregenerative environment with relevant cell populations to ensure normal tissue repair. Utilizing a diabetic mouse model, it is demonstrated that PtCuTe significantly facilitated the regeneration of highly vascularized skin, with the percentage of wound closure being over 90% on the 8th day, which is the best among the reported comparable multifunctional biomaterials.

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Cancer Imaging Application Note

Cancer Detection and Monitoring with the TriTomTM

Photoacoustic imaging has become a popular tool in preclinical cancer research as a noninvasive technique for monitoring tumor growth and therapeutic response. Specifically, photoacoustic imaging can provide high-sensitivity images of both superficial and deep vasculature and quantitative assessment of blood oxygen saturation without exogenous contrast. The TriTom small animal imaging platform provides high-resolution photoacoustic tomography (PAT) images, enabling whole-body in vivo anatomical, functional, and molecular analysis for longitudinal cancer studies.

SYSTEM SPECIFICATIONS
Imaging System                   TriTomTM
Excitation Wavelengths     460 – 1300nm
Spatial Resolution               Up to 160 µm (PA)                            
Up to 70 µm (FL)
Acquisition Time                 36 s per scan
Monitoring Microvascular Development

The microvascular network of a tumor not only regulates the supply of nutrients that contribute to growth and metastasis but influences the response to anticancer therapies. Preclinical studies of tumor growth and neovasculature development are, therefore, critical to fundamental cancer research and therapeutic development. The TriTom is a 3D imaging platform that can resolve the complex and size-varying blood vessels supplying the tumor and quantify the local density of microvessels. Further, the TriTom’s superior spatial resolution in all three anatomical planes allows for visualization and monitoring of the microvascular network from any angle. This unique advantage enables longitudinal monitoring of tumor vasculature development and evaluation of therapies targeting cancer blood supply.

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Figure 1: (a) TriTom observation of a tumor-bearing hairless mouse model and (b) corresponding MIP coronal slab constructed from TriTom data acquired with 700 and 1064 nm laser excitation. The high-resolution image shows the local tumor environment (red ROI) and supplying vascular structures (blue arrows). Scale bar = 5 mm.
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Figure 2: MIP coronal slabs encompassing anterior structures up to 10 mm deep in healthy (top) and tumor-bearing (bottom) mice. The reconstructed TriTom volumes show the high-resolution vascular anatomy maps produced by the TriTom without exogenous contrast agents. Additionally, the superior resolution in all three anatomical planes enables in vivo monitoring of tumor (orange ROI) growth and microvascular development (purple arrows). 1. Superficial lateral vein, 2. Intestines, 3. Superficial abdominal arteries, 4. Deep circumflex iliac artery, 5. Common iliac artery, 6. External iliac artery, 7. Lateral caudal vein. Scale bar = 5mm.
Tumor Growth Monitoring

Accurate noninvasive measurements of tumor size and morphology are crucial to evaluating the effects of novel therapies. However, current modalities provide an incomplete picture of the tumor environment due to poor spatial resolution and limited imaging depth. The TriTom is a high-resolution 3D imaging technology with superior molecular sensitivity in deep tissue. As a result, the TriTom images provide a detailed view of the tumor morphology and enable accurate longitudinal assessment of tumor growth. These key features make the TriTom a powerful tool for monitoring tumor growth, metastasis, and therapeutic response in preclinical cancer research.

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Figure 3:  in vivo evaluation of tumor growth. (a) High-resolution MIP of the 700 nm and 1064 nm TriTom volumes showing the tumor and its immediate environment. (b) Axial cross-section of the tumor noted by the dashed line in (a). This region corresponds to the H&E-stained tumor section (c) with corresponding structures (orange and yellow ROIs) and tumor microvasculature (arrows) identified and readily available for quantitative measurements. Scale bar = 1 mm.

Laser-Synthesized Germanium Nanoparticles as Biodegradable Material for Near-Infrared Photoacoustic Imaging and Cancer Phototherapy

Author(s): Iaroslav B. Belyaev, Ivan V. Zelepukin, Polina A. Kotelnikova, Gleb V. Tikhonowski, Anton A. Popov, Alina Yu. Kapitannikova, Jugal Barman, Alexey N. Kopylov, Daniil N. Bratashov, Ekaterina S. Prikhozhdenko, Andrei V. Kabashin, Sergey M. Deyev, Andrei V. Zvyagin

Abstract

Biodegradable nanomaterials can significantly improve the safety profile of nanomedicine. Germanium nanoparticles (Ge NPs) with a safe biodegradation pathway are developed as efficient photothermal converters for biomedical applications. Ge NPs synthesized by femtosecond-laser ablation in liquids rapidly dissolve in physiological-like environment through the oxidation mechanism. The biodegradation of Ge nanoparticles is preserved in tumor cells in vitro and in normal tissues in mice with a half-life as short as 3.5 days. Biocompatibility of Ge NPs is confirmed in vivo by hematological, biochemical, and histological analyses. Strong optical absorption of Ge in the near-infrared spectral range enables photothermal treatment of engrafted tumors in vivo, following intravenous injection of Ge NPs. The photothermal therapy results in a 3.9-fold reduction of the EMT6/P adenocarcinoma tumor growth with significant prolongation of the mice survival. Excellent mass-extinction of Ge NPs (7.9 L g−1 cm−1 at 808 nm) enables photoacoustic imaging of bones and tumors, following intravenous and intratumoral administrations of the nanomaterial. As such, strongly absorbing near-infrared-light biodegradable Ge nanomaterial holds promise for advanced theranostics.

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The development of ionizing radiation acoustic imaging (iRAI) for mapping the dose deep in the patient body during radiation therapy

Author(s): Wei Zhang, Dale Litzenberg, Yaocai Huang, Kai-Wei Chang, Ibrahim Oraiqat, Scott Hadley, Eduardo G. Moros, Man Zhang, Paul L. Carson, Kyle C. Cuneo, Issam EI Naqa, Xueding Wang

Abstract

Ionizing radiation acoustic imaging (iRAI) provides the potential to map the radiation dose during radiotherapy in real time. Described here is the development of iRAI volumetric imaging system in mapping the three-dimensional (3D) radiation dose deposition of clinical radiotherapy treatment plan with patient receiving radiation to liver tumor. The real-time visualizations of radiation dose delivered have been archived in patients with liver tumor under a clinical linear accelerator. This proof-of-concept study demonstrated the potential of iRAI to map the dose distribution in deep body during radiotherapy, potentially leading to personalized radiotherapy with optimal efficacy and safety.

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Toward in vivo dosimetry in external beam radiotherapy using x-ray acoustic computed tomography: A soft-tissue phantom study validation

Author(s): Hao Lei, Wei Zhang, Ibrahim Oraiqat, Zhipeng Liu, Jun Ni, Xueding Wang, Issam El Naqa

Abstract

Purpose: To study, using phantoms made from biological tissues, the feasibility and practical challenges of monitoring the position of the radiation beam and the deposited dose by x-ray acoustic computed tomography (XACT) during external beam radiotherapy delivery.

Material and methods: A prototype XACT system with a single immersion ultrasound transducer, which was positioned around the target sample driven by a motor-controlled rotation stage, was used to acquire the x-ray acoustic (XA) signals produced by a medical linear accelerator (Linac) to form an XACT image of the irradiated phantom. To investigate the feasibility of XACT in tracking the position of radiation dose, a large piece of veal liver with embedded fat tissue was imaged and beam misalignments were measured. Next, we explored the sensitivity of XACT in monitoring and quantifying the delivered dose, in which a block of porcine gel was embedded with equally spaced lard cylinders and imaged. The doses on the lard cylinders modulated by physical wedges were quantified from the XACT image and were verified by comparison to measurements from radiochromic films as the gold standard. Then, to simulate how XACT can perform in a targeted tissue in the human body, a porcine gel phantom with lard cylinders covered by different materials (bone, muscle, and air gap, respectively) was also imaged.

Results: The reconstructed XACT images of the phantoms show congruence with the boundaries of the beam field and the interfaces between the different tissue materials. The beam displacement from the target was tracked properly by the reconstructed XACT images. An intensity difference as small as 2.9% in delivered dose region can be measured from XACT images P = 0.02. The intensities of XACT images were highly correlated to the film measurements with an R2 better than 0.986. The expected variances of dose delivered to different target regions as a result of the difference in attenuation were successfully captured by the XACT images.

Conclusions: This study validated the feasibility of XACT in accurately obtaining relative dose maps of tissue-mimicking phantoms. XACT offers a practical method for verifying the beam position against the target and quantifying the relative dose delivered to the target during external beam radiotherapy.

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Custom Systems & Algorithms

PhotoSounds OEM line of products is an ideal starting point for the development of custom systems where the parallel acquisition of multiple channels is required. All our ADCs are streaming and allow the continuous acquisition of data straight to the receiving computer for processing or storage.

PhotoSound’s ADCs are feature-rich, they have multiple electronic and optical trigger inputs as well as programmable outputs that allow the timing control of additional devices. It is possible to combine multiple ADCs in parallel. Simultaneous acquisition of 4096 channels has been realized routinely.
Access to raw data as well as a user-friendly SDK allows for the easy development of any software and reconstruction algorithms.

PhotoSound Products Used

Legion ADC

Deep Learning Enabled Real-Time Photoacoustic Tomography System via Single Data Acquisition Channel

Y-Net: Hybrid Deep Learning Image Reconstruction for Photoacoustic Tomography In Vivo

TriTom

Spatiotemporal image reconstruction to enable high-frame-rate dynamic photoacoustic tomography with rotating-gantry volumetric imagers

GPU-Accelerated 3D Volumetric X-Ray-Induced Acoustic Computed Tomography

Author(s): Donghyun Lee, Eun-Yeong Park, Seongwook Choi, Hyeongsub Kim, Jung-joon Min, Changho Lee, and Chulhong Kim

ABSTRACT

X-ray acoustic imaging is a hybrid biomedical imaging technique that can acoustically monitor X-ray absorption distribution in biological tissues through the X-ray induced acoustic effect. In this study, we developed a 3D volumetric X-ray-induced acoustic computed tomography (XACT) system with a portable pulsed X-ray source and an arc-shaped ultrasound array transducer. 3D volumetric XACT images are reconstructed via the back-projection algorithm, accelerated by a custom-developed graphics processing unit (GPU) software. Compared with a CPU-based software, the GPU software reconstructs an image over 40 times faster. We have successfully acquired 3D volumetric XACT images of various lead targets, and this work shows that the 3D volumetric XACT system can monitor a high-resolution X-ray dose distribution and image X-ray absorbing structures inside biological tissues.

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Spatiotemporal Image Reconstruction to Enable High-Frame-Rate Dynamic Photoacoustic Tomography with Rotating-Gantry Volumetric Imagers

Author(s): Refik Mert Cam, Chao Wang, Weylan Thompson, Sergey A. Ermilov, Mark A. Anastasio, Umberto Villa

ABSTRACT

Significance

Dynamic photoacoustic computed tomography (PACT) is a valuable imaging technique for monitoring physiological processes. However, current dynamic PACT imaging techniques are often limited to two-dimensional spatial imaging. Although volumetric PACT imagers are commercially available, these systems typically employ a rotating measurement gantry in which the tomographic data are sequentially acquired as opposed to being acquired simultaneously at all views. Because the dynamic object varies during the data-acquisition process, the sequential data-acquisition process poses substantial challenges to image reconstruction associated with data incompleteness. The proposed image reconstruction method is highly significant in that it will address these challenges and enable volumetric dynamic PACT imaging with existing preclinical imagers.

Aim

The aim of this study is to develop a spatiotemporal image reconstruction (STIR) method for dynamic PACT that can be applied to commercially available volumetric PACT imagers that employ a sequential scanning strategy. The proposed reconstruction method aims to overcome the challenges caused by the limited number of tomographic measurements acquired per frame.

Approach

A low-rank matrix estimation-based STIR (LRME-STIR) method is proposed to enable dynamic volumetric PACT. The LRME-STIR method leverages the spatiotemporal redundancies in the dynamic object to accurately reconstruct a four-dimensional (4D) spatiotemporal image.

Results

The conducted numerical studies substantiate the LRME-STIR method’s efficacy in reconstructing 4D dynamic images from tomographic measurements acquired with a rotating measurement gantry. The experimental study demonstrates the method’s ability to faithfully recover the flow of a contrast agent with a frame rate of 10 frames per second, even when only a single tomographic measurement per frame is available.

Conclusions

The proposed LRME-STIR method offers a promising solution to the challenges faced by enabling 4D dynamic imaging using commercially available volumetric PACT imagers. By enabling accurate STIRs, this method has the potential to significantly advance preclinical research and facilitate the monitoring of critical physiological biomarkers.

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Water-Soluble Fe(II) Complexes for Theranostic Application: Synthesis, Photoacoustic Imaging, and Photothermal Conversion

Authors: Maeva Delcroix, Dr. Anil Reddy Marri, Stéphane Parant, Dr. Philippe C. Gros, Dr. Mathilde Bouché

ABSTRACT

Significant effort focused on developing photoactivatable theranostics for localized image guided therapy of cancer by thermal ablation. In this context iron complexes were recently identified as photoactivatable theranostic agents with adequate biocompatibility and body clearance. Herein, a series of FeII complexes bearing polypyridine or N-heterocyclic carbenes is reported that rely on rational complex engineering to red-shift their MLCT based excited-state deactivation via a straightforward approach. The non-radiative decay of their MLCT upon irradiation is exploited for theranostic purposes by combining both tracking in photoacoustic imaging (PA) and photothermal therapy (PTT). The influence of structural modifications introduced herein on the solubility and stability of the complexes in biorelevant aqueous media is discussed. The relationship between complexes’ design, production of contrast in photoacoustic and photothermal efficiency are explored to develop tailored PA/PTT theranostic agents.

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LIVE PRODUCT DEMONSTRATION AT THE PHOTOSOUND BOOTH 8539 DURING THE BiOS EXHIBITION

Visit the PhotoSound’s booth #8539 to meet our Production Manager, Sam Toler. Sam will have live product demonstrations featuring the MoleculUSTM, our dual-modality ultrasound and photoacoustic data acquisition unit that allows the simultaneous collection of ultrasound and photoacoustic channels sharing the same probe elements.

The MoleculUSTM can use linear, convex, and endocavitary handheld probes. Stop by PhotoSound’s booth #8539 to see live product demonstrations of the MoleculUSTM during the BiOS EXPO in San Francisco from January 27-28 2024.

We are excited to announce that PhotoSound Technologies Inc. has been selected as a finalist for the 2024 SPIE Prism Award for our new product, the MoleculUSTM, in the Biomedical category.

The SPIE Prism Awards recognize the best new photonics products and technologies on the market. We are honored to be among the finalists alongside such innovative companies at this year’s BIOS Exhibition at Photonics West.