我们感谢美国国家科学基金会（职业CBET-1055379）和美国国立卫生研究院（1RC4EY021357，1R01EY019951）的鼎力支持。我们还认识到支持从宋炜中国国家留学基金管理委员会。

1。系统配置<ol><li> PAOM子系统 <ol><li>照明光源：Nd：YAG激光（SPOT-10-100，UK：Elforlight有限公司，20μJ/脉冲; 2纳秒脉冲持续时间; 30 kHz的最大脉冲重复频率）。 </li><li>输出激光波长为1064 nm倍频532 nm的β- - 硼酸钡（BBO）晶体（福建福晶科技，圣何塞，CA）。进一步分割通过激光线镜像后，交付532 nm的光通过单模光纤（P1-460A-FC-5，Thorlabs公司），和1064 nm激光记录由一个光电二极管（DET10A，Thorlabs公司），这将触发PA信号的采集。 </li><li>出来的单模光纤的激光光被传递到由检流计（GM，QS-7，Nutfield的技术）和一个望远镜配置视网膜抑制（f1 = 75毫米和f2 = 14毫米，爱特蒙特光学）6。 </li><li>未聚焦的针换能器（40-MHz的中心频率16 MHz的带宽，0.4×0.4 mm 2的有源元件的大小，NIH资源Center为超声换能器技术，美国南加州大学）被放置在接触眼睑的检测PA产生的信号从视网膜。超声波的硅胶（SONOTECH）之间施加良好的声学耦合的换能器的塞尖和动物眼睑。 </li><li> PA信号被放大由两个放大器ZFL-500LN +，Mini-Circuits公司，和5073PR，奥林巴斯，数字化的数据采集板（CS14200，测控应用）。 </li></ol></li><li> SD-OCT子系统的 <ol><li>低相干光源：一个宽带超发光二极管（IPSDD0804，InPhenix中心波长：840 nm的6 dB带宽为50nm），这就决定了轴向分辨率为6微米。 </li><li>的近红外光被分割的参考臂和样品臂由一个50×50定制的单模光纤耦合器（OZ光学）。 </li><li>由热镜（FM02，Thorlabs公司）的结合PAOM照明灯后，华侨城的样品臂共享相同的扫描和交付光学无线网络日PAOM 6。 </li><li>一个自制的光谱仪是用来记录的SD-OCT干扰信号，行扫描CCD相机，E2V（AVIIVA SM2）允许一个A线率24千赫。典型的光谱仪的设计可以从几个原样文献11和光纤耦合的SD-OCT光谱仪发现现在市售。 SD-OCT灵敏度的测量是更好的超过90分贝。 </li></ol></li><li> 扫描计划 <ol><li>极速的2-D的光栅扫描的检流计控制由一个模拟输出板（PCI-6731，美国国家仪器公司），这也同时触发PAOM的激光发射和华侨城光谱仪的信号采集。其结果是，数据采集在PAOM和OCT子系统是同步的。 </li><li>收购的PAOM数据所引发的光电二极管的记录PAOM激光序列（见1.1.2）。 </li><li> 3-D的容积图像或2-D眼底图像构造256 B-扫描图像（256线每个B扫描图像）。 </li></ol></li></ol> 2。系统调整<ol><li>最大化的BBO晶体的倍频效率和单模光纤的耦合效率。优化时，PAOM的照明光，穿LG3人员保护眼睛的护目镜（Thorlabs公司）。 </li><li>照准光纤输出的激光的PAOM至2.0毫米的直径。 </li><li>对齐合并的PAOM和SD-OCT同轴照明灯。 </li><li> 〜40 NJ /脉冲和SD-OCT设置PAOM激发光探测光〜0.8兆瓦，这两个据报道，人眼安全6,12。 </li></ol> 3， 在体内多模态视网膜成像<ol><li>大鼠转移到透明聚丙烯框，和异氟醚（凤凰制药公司）和正常空气中在1.5％的浓度，流速为2.0升/分钟和10分钟的混合物麻醉动物。 </li><li>抑制麻醉大鼠在homema五轴可调自由（ 图1），并保持它的体温通过加热的垫（Repti千卡，缩放的实验室，公司）在〜37℃的保持器与。整个实验过程中的浓度为1.0％和1.5升/分钟的流速与混合的异氟醚和正常的空气通过吸入气体维持麻醉。 </li><li>剪切的睫毛，用手术剪，1％托品滴眼液扩瞳，用0.5％盐酸丁卡因滴眼液虹膜括约肌瘫痪。的人工泪液下降（Systane，爱尔康公司），鼠眼每隔一分钟，防止角膜脱水和白内障的形成。监测动物的心率，呼吸和血氧脉搏血氧仪（8,600 V，燕牌医疗，MN）在成像过程中。 </li><li>打开SD-OCT照明灯和检查探测光〜0.8毫瓦。 </li><li>激活振镜扫描。对准SD-OCT照射的光传输大鼠视网膜上，视网膜的感兴趣区域（ROI），并确定调整的五轴动物持有人。这里，视盘是故意的视场的中心放置在，而的ROI的选择应基于不同的研究要求。 </li><li>进一步调整的动物保持器，直至达到最佳的光学聚焦在两个扫描方向（通过切换的光栅扫描方向），以优化的SD-OCT成像质量的视网膜截面。 </li><li>准备针换能器上的5轴的调节平台，应用超声波凝胶下降到换能器的前端，并轻轻地接触的振子的动物眼睑的小费。 </li><li>设置外部触发模式PAOM激光，开始检流计扫描，和激活的PAOM剖动物视网膜图像的实时显示。仔细调整换能器的方向，直到PAOM图像具有最佳的信号 - 噪声比（SNR），并在此期间，显示了一个均匀DISTributed PA振幅模式在两个扫描方向。 </li><li>设置扫描参数，并同时进行视网膜SD-OCT和PAOM的成像。重构三维图像SD-OCT和PAOM的离线。我们的重建代码写在Matlab和三维可视化实现uing一个免费的（Volview，Kitware）的。 SD-OCT重建算法，可以在文献中找到，11和在参考文献中可以找到为PAOM重建算法。6和号13。如果需要，重复步骤3.7）-3.9）。 </li><li>实验结束后，关闭SD-OCT探测光的，持有人立即将该动物，并保持温暖，直到它自然唤醒。动物保持在黑暗的环境为眼睛恢复加床小时。整个实验持续时间，包括动物麻醉和图像采集，是一个有经验的运营商不到30分钟。 </li></ol>

<ol>
	<li>Kinyoun, J. L., Martin, D. C., Fujimoto, W. Y., Leonetti, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ophthalmoscopy+versus+fundus+photographs+for+detecting+and+grading+diabetic+retinopathy.">Ophthalmoscopy versus fundus photographs for detecting and grading diabetic retinopathy.</a> Invest. Ophthalmol. Vis. Sci. 33 (6), 1888-1893 (1992).</li><li>Schuman, J. S., Wollstein, G., Farra, T., Hertzmark, E., Aydin, A., Fujimoto, J. G., Paunescu, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+optic+nerve+head+measurements+obtained+by+optical+coherence+tomography+and+confocal+scanning+laser+ophthalmoscopy.">Comparison of optic nerve head measurements obtained by optical coherence tomography and confocal scanning laser ophthalmoscopy.</a> Am. J. Ophthalmol. 135 (4), 504-512 (2003).</li><li>Str&#248;m, C., Sander, B., Larsen, N., Larsen, M., Lund-Andersen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diabetic+macular+edema+assessed+with+optical+coherence+tomography+and+stereo+fundus+photography.">Diabetic macular edema assessed with optical coherence tomography and stereo fundus photography.</a> Invest. Ophthalmol. Vis. Sci. 43 (1), 241-245 (2002).</li><li>Hu, S., Maslov, K., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+Optical-resolution+Photoacoustic+Microscopy.">Three-dimensional Optical-resolution Photoacoustic Microscopy.</a> J. Vis. Exp. (51), e2729 (2011).</li><li>Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiscale+photoacoustic+microscopy+and+computed+tomography.">Multiscale photoacoustic microscopy and computed tomography.</a> Nat. Photonics. 3 (9), 503-509 (2009).</li><li>Jiao, S., Jiang, M., Hu, J., Fawzi, A., Zhou, Q., Shung, K. K., Puliafito, C. A., Zhang, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoacoustic+ophthalmoscopy+for+in+vivo+retinal+imaging.">Photoacoustic ophthalmoscopy for in vivo retinal imaging.</a> Opt. Express. 18 (4), 3967-3972 (2010).</li><li>Wei, Q., Liu, T., Jiao, S., Zhang, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+chorioretinal+vasculature+in+albino+rats+using+photoacoustic+ophthalmoscopy.">Image chorioretinal vasculature in albino rats using photoacoustic ophthalmoscopy.</a> J. Mod. Optic. 58 (21), 1997-2001 (2011).</li><li>Liu, T., Wei, Q., Wang, J., Jiao, S., Zhang, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=H.F+Combined+photoacoustic+microscopy+and+optical+coherence+tomography+can+measure+metabolic+rate+of+oxygen.">H.F Combined photoacoustic microscopy and optical coherence tomography can measure metabolic rate of oxygen.</a> Biomed. Opt. Express. 2 (5), 1359-1365 (2011).</li><li>Yu, D., Cringle, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxygen+distribution+and+consumption+within+the+retina+in+vascularised+and+avascular+retinas+and+in+animal+models+of+retinal+disease.">Oxygen distribution and consumption within the retina in vascularised and avascular retinas and in animal models of retinal disease.</a> Prog. Retin. Eye Res. 20 (2), 175-208 (2001).</li><li>Song, W., Wei, Q., Liu, T., Kuai, D., Burke, J. M., Jiao, S., Zhang, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrating+photoacoustic+ophthalmoscopy+with+scanning+laser+ophthalmoscopy,+optical+coherence+tomography,+and+fluorescein+angiography+for+a+multimodal+retinal+imaging+platform.">Integrating photoacoustic ophthalmoscopy with scanning laser ophthalmoscopy, optical coherence tomography, and fluorescein angiography for a multimodal retinal imaging platform.</a> J. Biomed. Opt. 17 (6), 061206 (2012).</li><li>Mark, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Brezinski Optical Coherence Tomography: Principles and Applications. , (2006).</li><li>Hu, S., Rao, B., Maslov, K., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Label-free+photoacoustic+ophthalmic+angiography.">Label-free photoacoustic ophthalmic angiography.</a> Opt. Lett. 35 (1), 1-3 (2010).</li><li>Zhang, H. F., Maslov, K., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+of+subcutaneous+structures+using+functional+photoacoustic+microscopy.">In vivo imaging of subcutaneous structures using functional photoacoustic microscopy.</a> Nature protocols. 2, 797-804 (2007).</li><li>Ling, T., Chen, S. L., Guo, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-sensitivity+and+wide-directivity+ultrasound+detection+using+high+Q+polymer+microring+resonators.">High-sensitivity and wide-directivity ultrasound detection using high Q polymer microring resonators.</a> Appl. Phys. Lett. 98 (20), 204103 (2011).</li><li>Xie, Z., Jiao, S., Zhang, H. F., Puliafito, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser-scanning+optical-resolution+photoacoustic+microscopy.">Laser-scanning optical-resolution photoacoustic microscopy.</a> Opt. Lett. 34, 1771-1773 (2009).</li></ol>

西北大学实验动物护理和使用委员会的批准，所有实验动物的程序。

在这里，我们提出了一个详细的说明同时在体内视网膜大鼠的用眼PAOM结合SD-OCT成像。 ，或许，基于光散射SD-OCT视网膜成像3临床“金标准”，但是，这是不敏感的检测在视网膜上的光吸收。新开发的PAOM是基于光学吸收的唯一的眼科成像方式，提供的光吸收特性的视网膜6。 ，因为血红蛋白和黑色素是内生性较强的光吸收色素，PAOM使调查的解剖和功能的视网膜RPE /脉络膜血管...

integrated photoacoustic ophthalmoscopy and spectral-domain optical coherence tomography

极大地受益于各种非侵入性的眼科成像技术的重大眼部疾病的临床诊断和基本的调查。现有的视网膜成像方式，如共焦激光扫描眼底镜检查（CSLO）2，眼底照相，光学相干断层扫描（OCT），有显着贡献，监测疾病的起始和级数，并开发新的治疗策略。然而，它们主要依靠的背面反射的光子从视网膜。因此，在视网膜的光吸收特性，这通常是紧密联系在一起的视网膜病理生理状态，是无法由传统的成像技术。 “光声眼底镜检查（PAOM）是一种新兴的的视网膜成像方式，允许在眼内的光吸收对比检测，具有灵敏度高4-7。在PAOM南交付osecond激光脉冲通过瞳孔扫过的眼后诱导光声（PA）检测到的信号，这是由一个未聚焦的超声波换能器连接到眼睑。因为强烈的光吸收的血红蛋白和黑色素，PAOM是能够非侵入性成像视网膜和脉络膜vasculatures的，而视网膜色素上皮细胞（RPE）在高对比度的黑色素6,7。更重要的是，发达的光声光谱成像5,8的基础上，PAOM有可能映射在视网膜新生血管中的血红蛋白氧饱和度，它可以致盲性疾病，如糖 ​​尿病性视网膜病变的生理和病理研究的关键和新生血管性年龄相关性黄斑变性。 此外，现有的光学吸收为基础的眼科影像学检查方法，PAOM可以集成完善的临床眼科成像TEchniques实现多个光学对比6,10基础上的眼睛，更全面的解剖和功能的评价。在这项工作中，我们整合PAOM和谱域OCT（SD-OCT），用于同时在体内视网膜成像大鼠，其中揭示的视网膜的光的吸收和散射特性。的系统配置，系统校准和图像采集。

图2示出的2-D SD-OCT和PAOM白化病大鼠（A和B）和着色大鼠（C和D），分别在同时获得的眼底图像。在SD-OCT的眼底图像（ 图2A和2C），视网膜血管有深色的外观，由于探测光的血红蛋白吸收。 PAOM除了视网膜血管（ 图2B中的RV），可视化的的脉络膜vasculatures（CV在图2B）在白化病眼，因为缺乏RPE黑色素。由于色素的眼睛具有高黑?...

Watch this Scientific Journal Video about Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography at JoVE.com

Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography

光声眼科（PAOM）的，一个基于光学吸收的成像模态，提供了互补的评价的视网膜的当前可用的眼科成像技术。我们报告的使用PAOM集成与谱域光学相干断层扫描（SD-OCT），同时多式联运大鼠视网膜成像。

集成光声眼底镜检查和谱域光学相干断层扫描

Both the clinical diagnosis and fundamental investigation of major ocular diseases greatly benefit from various non-invasive ophthalmic imaging ...

integrated-photoacoustic-ophthalmoscopy-spectral-domain-optical

Research

JoVE Journal

Bioengineering

11.4K 次观看.  Northwestern University. 光声眼科（PAOM）的，一个基于光学吸收的成像模态，提供了互补的评价的视网膜的当前可用的眼科成像技术。我们报告的使用PAOM集成与谱域光学相干断层扫描（SD-OCT），同时多式联运大鼠视网膜成像。

视频: Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography

Three-dimensional Optical-resolution Photoacoustic Microscopy

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. 
The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)1, where the optical irradiation is focused to the diffraction limit to achieve cellular1 or even subcellular2 level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy3 or with optical-scattering-based OCT4 (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. 
Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology5, 6, ophthalmology7, 8, vascular biology9, and dermatology10. In this video, we teach the system configuration and alignment of OR-PAM as well as the experimental procedures for in vivo functional microvascular imaging.

Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.

三维光学分辨率的光声显微镜

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As ...

科研

生物工程

Detection and Isolation of Circulating Melanoma Cells using Photoacoustic Flowmetry

Circulating tumor cells (CTCs) are those cells that have separated from a macroscopic tumor and spread through the blood and lymph systems to seed secondary tumors1,2,3. CTCs are indicators of metastatic disease and their detection in blood samples may be used to diagnose cancer and monitor a patient&prime;s response to therapy. Since CTCs are rare, comprising about one tumor cell among billions of normal blood cells in advanced cancer patients, their detection and enumeration is a difficult task. We exploit the presence of pigment in most melanoma cells to generate photoacoustic, or laser induced ultrasonic waves in a custom flow cytometer for detection of circulating melanoma cells (CMCs)4,5. This process entails separating a whole blood sample using centrifugation and obtaining the white blood cell layer. If present in whole blood, CMCs will separate with the white blood cells due to similar density. These cells are resuspended in phosphate buffered saline (PBS) and introduced into the flowmeter. Rather than a continuous flow of the blood cell suspension, we induced two phase flow in order to capture these cells for further study. In two phase flow, two immiscible liquids in a microfluidic system meet at a junction and form alternating slugs of liquid6,7. PBS suspended white blood cells and air form microliter slugs that are sequentially irradiated with laser light. The addition of a surfactant to the liquid phase allows uniform slug formation and the user can create different sized slugs by altering the flow rates of the two phases. Slugs of air and slugs of PBS with white blood cells contain no light absorbers and hence, do not produce photoacoustic waves. However, slugs of white blood cells that contain even single CMCs absorb laser light and produce high frequency acoustic waves. These slugs that generate photoacoustic waves are sequestered and collected for cytochemical staining for verification of CMCs.

We have developed a flow cytometer using laser induced ultrasound to detect circulating melanoma cells as an early indicator of metastatic disease.

使用光声血流循环黑色素瘤细胞的检测和隔离

Circulating tumor cells (CTCs) are those cells that have separated from a macroscopic tumor and spread through the blood and lymph systems to seed ...

In vitro Synthesis of Native, Fibrous Long Spacing and Segmental Long Spacing Collagen

Collagen fibrils are present in the extracellular matrix of animal tissue to provide structural scaffolding and mechanical strength. These native collagen fibrils have a characteristic banding periodicity of ~67 nm and are formed in vivo through the hierarchical assembly of Type I collagen monomers, which are 300 nm in length and 1.4 nm in diameter. In vitro, by varying the conditions to which the monomer building blocks are exposed, unique structures ranging in length scales up to 50 microns can be constructed, including not only native type fibrils, but also fibrous long spacing and segmental long spacing collagen. Herein, we present procedures for forming the three different collagen structures from a common commercially available collagen monomer. Using the protocols that we and others have published in the past to make these three types typically lead to mixtures of structures. In particular, unbanded fibrils were commonly found when making native collagen, and native fibrils were often present when making fibrous long spacing collagen. These new procedures have the advantage of producing the desired collagen fibril type almost exclusively. The formation of the desired structures is verified by imaging using an atomic force microscope.

In vitro Synthesis of Native, Fibrous Long Spacing and Segmental Long Spacing Collagen

Simple and reproducible procedures are described for making three structurally distinct collagen assemblies from a common commercially available Type I collagen monomer. Native type, fibrous long spacing or segmental long spacing collagen can be constructed by varying the conditions to which the 300 nm long and 1.4 nm diameter monomer building block is exposed.

在体外合成的原住民，纤维长间距“和”分段长间距胶原蛋白

Collagen fibrils are present in the  extracellular matrix of animal tissue to provide structural scaffolding and  mechanical strength. These native ...

Photoacoustic Cystography

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The risk of bladder cancers in children due to radiation exposure is more significant than many other cancers. Here we demonstrate the feasibility of nonionizing and noninvasive photoacoustic (PA) imaging of urinary bladders, referred to as photoacoustic cystography (PAC), using near-infrared (NIR) optical absorbents (i.e. methylene blue, plasmonic gold nanostructures, or single walled carbon nanotubes) as an optical-turbid tracer. We have successfully imaged a rat bladder filled with the optical absorbing agents using a dark-field confocal PAC system. After transurethral injection of the contrast agents, the rat's bladders were photoacoustically visualized by achieving significant PA signal enhancement. The accumulation was validated by spectroscopic PA imaging. Further, by using only a laser pulse energy of less than 1 mJ/cm2 (1/20 of the safety limit), our current imaging system could map the methylene-blue-filled-rat-bladder at the depth of beyond 1 cm in biological tissues in vivo. Both in vivo and ex vivo PA imaging results validate that the contrast agents were naturally excreted via urination. Thus, there is no concern regarding long-term toxic agent accumulation, which will facilitate clinical translation.

Photoacoustic cystography (PAC) has a great potential to map urinary bladders, a radiation sensitive internal organ in pediatric patients, without using any ionizing radiation or toxic contrast agent. Here we demonstrate the use of PAC for mapping urinary bladders with an injection of optical-opaque tracers in rats in vivo.

光声膀胱造影

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The ...

Preparation and Photoacoustic Analysis of Cellular Vehicles Containing Gold Nanorods

Gold nanorods are attractive for a range of biomedical applications, such as the photothermal ablation and the photoacoustic imaging of cancer, thanks to their intense optical absorbance in the near-infrared window, low cytotoxicity and potential to home into tumors. However, their delivery to tumors still remains an issue. An innovative approach consists of the exploitation of the tropism of tumor-associated macrophages that may be loaded with gold nanorods in vitro. Here, we describe the preparation and the photoacoustic inspection of cellular vehicles containing gold nanorods. PEGylated gold nanorods are modified with quaternary ammonium compounds, in order to achieve a cationic profile. On contact with murine macrophages in ordinary Petri dishes, these particles are found to undergo massive uptake into endocytic vesicles. Then these cells are embedded in biopolymeric hydrogels, which are used to verify that the stability of photoacoustic conversion of the particles is retained in their inclusion into cellular vehicles. We are confident that these results may provide new inspiration for the development of novel strategies to deliver plasmonic particles to tumors.

We show the preparation and address the feasibility of cellular vehicles containing gold nanorods for the photoacoustic imaging of cancer.

含有金纳米棒蜂窝车辆的制备及光声分析

Gold nanorods are attractive for a range of biomedical applications, such as the photothermal ablation and the photoacoustic imaging of cancer, thanks to ...

Computed Tomography and Optical Imaging of Osteogenesis-angiogenesis Coupling to Assess Integration of Cranial Bone Autografts and Allografts

A major parameter determining the success of a bone-grafting procedure is vascularization of the area surrounding the graft. We hypothesized that implantation of a bone autograft would induce greater bone regeneration by abundant blood vessel formation. To investigate the effect of the graft on neovascularization at the defect site, we developed a micro&#8211;computed tomography (&#181;CT) approach to characterize newly forming blood vessels, which involves systemic perfusion of the animal with a polymerizing contrast agent. This method enables detailed vascular analysis of an organ in its entirety. Additionally, blood perfusion was assessed using fluorescence imaging (FLI) of a blood-borne fluorescent agent. Bone formation was quantified by FLI using a hydroxyapatite-targeted probe and &#181;CT analysis. Stem cell recruitment was monitored by bioluminescence imaging (BLI) of transgenic mice that express luciferase under the control of the osteocalcin promoter. Here we describe and demonstrate preparation of the allograft, calvarial defect surgery, &#181;CT scanning protocols for the neovascularization study and bone formation analysis (including the in vivo perfusion of contrast agent), and the protocol for data analysis.
The 3D high-resolution analysis of vasculature demonstrated significantly greater angiogenesis in animals with implanted autografts, especially with respect to arteriole formation. Accordingly, blood perfusion was significantly higher in the autograft group by the 7th day after surgery. We observed superior bone mineralization and measured greater bone formation in animals that received autografts. Autograft implantation induced resident stem cell recruitment to the graft-host bone suture, where the cells differentiated into bone-forming cells between the 7th and 10th postoperative day. This finding means that enhanced bone formation may be attributed to the augmented vascular feeding that characterizes autograft implantation. The methods depicted may serve as an optimal tool to study bone regeneration in terms of tightly bounded bone formation and neovascularization.

Implantation of autologous and allogeneic bone grafts constitute accepted approaches to treat major craniofacial bone loss. Yet the effect of graft composition on the interplay among neovascularization, cell differentiation and bone formation is unclear. We present a multimodal imaging protocol aimed to elucidate the angiogenesis-osteogenesis interdependence at the graft proximity.

计算机断层扫描和成骨血管生成耦合光学成像评估头盖骨自体移植和移植物的整合

A major parameter determining the success of a bone-grafting procedure is vascularization of the area surrounding the graft. We hypothesized that ...

Switchable Acoustic and Optical Resolution Photoacoustic Microscopy for In Vivo Small-animal Blood Vasculature Imaging

Photoacoustic microscopy (PAM) is a fast-growing invivo imaging modality that combines both optics and ultrasound, providing penetration beyond the optical mean free path (~1 mm in skin) with high resolution. By combining optical absorption contrast with the high spatial resolution of ultrasound in a single modality, this technique can penetrate deep tissues. Photoacoustic microscopy systems can have either a low acoustic resolution and probe deeply or a high optical resolution and probe shallowly. It is challenging to achieve high spatial resolution and large depth penetration with a single system. This work presents an AR-OR-PAM system capable of both high-resolution imaging at shallow depths and low-resolution deep-tissue imaging of the same sample in vivo. A lateral resolution of 4 &#181;m with 1.4 mm imaging depth using optical focusing and a lateral resolution of 45 &#181;m with 7.8 mm imaging depth using acoustic focusing were successfully demonstrated using the combined system. Here,&#160;in vivo&#160;small-animal blood vasculature imaging is performed to demonstrate its biological imaging capability.

Switchable Acoustic and Optical Resolution Photoacoustic Microscopy for In Vivo Small-animal Blood Vasculature Imaging

Here a switchable acoustic resolution (AR) and optical resolution (OR) photoacoustic microscopy (AR-OR-PAM) system capable of both high resolution imaging at shallow depth and low resolution deep tissue imaging on the same sample in vivo is demonstrated.

可切换声光学分辨率光声显微镜<em&gt;体内</em&gt;小动物血液血管成像

Photoacoustic microscopy (PAM) is a fast-growing invivo imaging modality that combines both optics and ultrasound, providing penetration beyond the ...

A High-performance Compact Photoacoustic Tomography System for In Vivo Small-animal Brain Imaging

In vivo small-animal imaging has an important role to play in preclinical studies. Photoacoustic tomography (PAT) is an emerging hybrid imaging modality that shows great potential for both preclinical and clinical applications. Conventional optical parametric oscillator-based PAT (OPO-PAT) systems are bulky and expensive and cannot provide high-speed imaging. Recently, pulsed-laser diodes (PLDs) have been successfully demonstrated as an alternative excitation source for PAT. Pulsed-laser diode PAT (PLD-PAT) has been successfully demonstrated for high-speed imaging on photoacoustic phantoms and biological tissues. This work provides a visualized experimental protocol for in vivo brain imaging using PLD-PAT. The protocol includes the compact PLD-PAT system configuration and its description, animal preparation for brain imaging, and a typical experimental procedure for 2D cross-sectional rat brain imaging. The PLD-PAT system is compact and cost-effective and can provide high-speed, high-quality imaging. Brain images collected in vivo at various scan speeds are presented.

A High-performance Compact Photoacoustic Tomography System for In Vivo Small-animal Brain Imaging

A compact pulsed-laser diode-based photoacoustic tomography (PLD-PAT) system for high-speed in vivo brain imaging in small animals is demonstrated.

高性能紧凑型光声层析成像系统<em&gt;体内</em&gt;小动物脑成像

In vivo small-animal imaging has an important role to play in preclinical studies. Photoacoustic tomography (PAT) is an emerging hybrid imaging modality ...

Multimodal Volumetric Retinal Imaging by Oblique Scanning Laser Ophthalmoscopy (oSLO) and Optical Coherence Tomography (OCT)

While fluorescence imaging is widely used in ophthalmology, a large field of view (FOV) three-dimensional (3D) fluorescence retinal image is still a big challenge with the state-of-the-art retinal imaging modalities because they would require z-stacking to compile a volumetric dataset. Newer optical coherence tomography (OCT) and OCT angiography (OCTA) systems overcome these restrictions to provide three-dimensional (3D) anatomical and vascular images, but the dye-free nature of OCT cannot visualize leakage indicative of vascular dysfunction. This protocol describes a novel oblique scanning laser ophthalmoscopy (oSLO) technique that provides 3D volumetric fluorescence retinal imaging. The setup of the imaging system generates the oblique scanning by a dove tail slider and aligns the final imaging system at an angle to detect fluorescent cross-sectional images. The system uses the laser scanning method, and therefore, allows an easy incorporation of OCT as a complementary volumetric structural imaging modality. In vivo imaging on rat retina is demonstrated here. Fluorescein solution is intravenously injected to produce volumetric fluorescein angiography (vFA).

Multimodal Volumetric Retinal Imaging by Oblique Scanning Laser Ophthalmoscopy oSLO and Optical Coherence Tomography OCT

Here, we present a protocol to get a large field of view (FOV) three-dimensional (3D) fluorescence and OCT retinal image by using a novel imaging multimodal platform. We will introduce the system setup, the method of alignment, and the operational protocols. In vivo imaging will be demonstrated, and representative results will be provided.

斜扫描激光检眼镜 (奥斯陆) 与光学相干层析成像 (OCT) 的多模态视网膜成像

While fluorescence imaging is widely used in ophthalmology, a large field of view (FOV) three-dimensional (3D) fluorescence retinal image is still a big ...

Nondestructive Monitoring of Degradable Scaffold-Based Tissue-Engineered Blood Vessel Development Using Optical Coherence Tomography

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial bypass. Characterization of the growth dynamics and remodeling process of degradable polymer scaffold-based tissue-engineered blood vessels (TEBVs) with pulsatile stimulation is crucial for vascular tissue engineering. Optical imaging techniques stand out as powerful tools for monitoring vascularization of engineered tissue enabling high-resolution imaging in real-time culture. This paper demonstrates a nondestructive and fast real-time imaging strategy to monitor the growth and remodeling of TEBVs in long-term culture by using optical coherence tomography (OCT). Geometric morphology is evaluated, including vascular remodeling process, wall thickness, and comparison of TEBV thickness in different culture time points and presence of pulsatile stimulation. Finally, OCT provides practical possibilities for real-time observation of the degradation of polymer in the reconstructing tissues under pulsatile stimulation or not and in each vessel segment, by compared with the assessment of polymer degradation using scanning electron microscopic(SEM) and polarized microscope.

A step by step protocol for nondestructive and long-period monitoring the process of vascular remodeling and scaffold degradation in real-time culture of biodegradable polymeric scaffold-based tissue-engineered blood vessels with pulsatile stimulation using optical coherence tomography is described here.

基于光学相干断层扫描的可降解支架组织工程血管发育的无损监测

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial ...