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Passive ultrasound aided acoustic resolution photoacoustic microscopy imaging for layered heterogeneous media
摘要： Photoacoustic imaging reconstructions usually assume a known speed-of-sound (SOS) distribution; however, in most cases, the SOS distribution is not revealed and is dif?cult to estimate from photoacoustic signals. In this paper, we propose passive ultrasound aided acoustic resolution photoacoustic microscopy which simultaneously reconstructs SOS distributions and photoacoustic images for layered heterogeneous media. The passive ultrasound is a kind of laser-induced acoustic wave generated by a transducer absorbing the backscattered light. It can be used to measure the layer thicknesses due to its sensitivity to structural information and broad bandwidth and further determine the SOS distributions. After estimating the SOS distributions, a phase shift plus interpo- lation is employed to reconstruct the photoacoustic image for heterogeneous media. Without intro- ducing additional hardware, this method can be conveniently incorporated into a conventional photoacoustic imaging system. A curved shell immersed in water is adopted as a layered heteroge- neous phantom, and the proposed method reconstructs the targets (carbon rods) under this shell. Under the test of a 5 MHz focused transducer (NA 0.25), the maximum reconstruction deviation of 1.2 mm carbon rods is only 0.15 mm.
关键词： passive ultrasound,speed-of-sound distribution,acoustic resolution photoacoustic microscopy,layered heterogeneous media,photoacoustic imaging
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - From Nanostructured Piezoelectric Materials to Broadband Transducers for High Resolution Ultrasonic Imaging
摘要： One-dimensional (1D) piezoelectric nanotubes have been fabricated and integrated for producing high frequency nanotube array ultrasonic transducers for high resolution ultrasonic imaging. We find that the nanotube structural feature and the unique nanoconfinement-induced crystal and polarization orientation lead to outstanding piezoelectric material properties and the resulting superior transducer performance. The nanotube array ultrasonic transducers show a broad bandwidth of 126 % (-6 dB) at 108 MHz, with significantly improved sensitivity in comparison with conventional thin film transducers despite the size shrinkage. We further demonstrate high resolution scanning ultrasonic imaging and photoacoustic imaging using the obtained nanotube array transducers, exhibiting great application values.
关键词： piezoelectric nanotubes,high resolution imaging,ultrasonic transducers,photoacoustic imaging
更新于2025-09-04 15:30:14
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Evaluation of renal oxygen saturation using photoacoustic imaging for the early prediction of chronic renal function in a model of ischemia-induced acute kidney injury
摘要： To evaluate the utility of photoacoustic imaging in measuring changes in renal oxygen saturation after ischemia-induced acute kidney injury, and to compare these measurements with histological findings and serum levels of kidney function.
关键词： chronic renal function,ischemia-reperfusion,renal oxygen saturation,acute kidney injury,photoacoustic imaging
更新于2025-09-04 15:30:14
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Exosome-like Nanozyme Vesicles for H2O2-responsive Catalytic Photoacoustic Imaging of Xenograft Nasopharyngeal Carcinoma
摘要： Photoacoustic imaging (PAI) is an attractive imaging modality, which is promising for clinical cancer diagnosis due to its advantages on deep tissue penetration and fine spatial resolution. However, few tumor catalytic/responsive PAI strategies are developed. Here, we design an exosome-like nanozyme vesicle for in vivo H2O2-responsive PAI of nasopharyngeal carcinoma (NPC). The intrinsic peroxidase-like activity of graphene quantum dot nanozyme (GQDzyme) effectively converts the 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) into its oxidized form in the presence of H2O2. The oxidized ABTS exhibits strong near-infrared (NIR) absorbance, rendering it to be an ideal contrast agent for PAI. Thus, GQDzyme/ABTS nanoparticle is a novel type of catalytic PAI contrast agent which is sensitive to H2O2 produced from NPC cells. Furthermore, we develop an approach to construct exosome-like nanozyme vesicle via biomimetic functionalization of GQDzyme/ABTS nanoparticle with natural erythrocyte membrane modified with folate acid. In vivo animal experiments demonstrated that, this exosome-like nanozyme vesicle effectively accumulated in NPC and selectively triggered catalytic PAI for NPC. In addition, our nanozyme vesicle exhibits excellent biocompatibility and stealth ability for long blood circulation. Together, we demonstrate that GQDzyme/ABTS based exosome-like nanozyme vesicle is an ideal nanoplatform for developing deep-tissue tumor-targeted catalytic PAI in vivo.
关键词： photoacoustic imaging,nasopharyngeal carcinoma,H2O2-responsive,graphene quantum dot nanozyme,exosome-like vesicle,erythrocyte membranes
更新于2025-09-04 15:30:14
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Auto-fluorescent polymer nanotheranostics for self-monitoring of cancer therapy via triple-collaborative strategy
摘要： Aberrant regulation of angiogenesis supply sufficient oxygen and nutrients to exacerbate tumor progression and metastasis. Taking this hallmark of cancer into account, reported here is a self-monitoring and triple-collaborative therapy system by auto-fluorescent polymer nanotheranostics which could be concurrently against angiogenesis and tumor cell growth by combining the benefits of anti-angiogenesis, RNA interfere and photothermal therapy (PTT). Auto-fluorescent amphiphilic polymer polyethyleneimine-polylactide (PEI-PLA) with positive charge can simultaneously load hydrophobic antiangiogenesis agent combretastatin A4 (CA4), NIR dye IR825 and absorb negatively charged heat shock protein 70 (HSP70) inhibitor (siRNA against HSP70) to construct self-monitoring nanotheranostics (NPICS). NPICS can effectively restrain the expression of HSP70 to reduce their endurance to the IR825-mediated PTT, leading to an enhanced photocytotoxicity. In a xenograft mouse tumor model, NPICS show an effect of inhibition of tumor angiogenesis and also display a highly synergistic anticancer efficacy with NIR laser irradiation. Significantly, based on its inherent auto-fluorescence, PEI-PLA not only serves as the drug carrier, but also as the self-monitor to real-time track NPICS biodistribution and tumor accumulation via fluorescence imaging. Moreover, IR825 endows NPICS could also be used as photoacoustic (PA) agents for in vivo PA imaging. This nanoplatform shows enormous potentials in cancer theranostics.
关键词： photothermal therapy,gene silencing,self-monitoring,fluorescence/photoacoustic imaging,anti-angiogenesis therapy
更新于2025-09-04 15:30:14