Encapsulated Conjugated Oligomer Nanoparticles for Real‐Time Photoacoustic Sentinel Lymph Node Imaging and Targeted Photothermal Therapy

Abstract

Noninvasive and nonionizing imaging of sentinel lymph nodes (SLN) is highly desirable for the detection of breast cancer metastasis through sentinel lymph node biopsy. Photoacoustic (PA) imaging is an emerging imaging technique that can serve as a suitable approach for SLN imaging. Herein, novel conjugated oligomer based nanoparticles (NPs) with strong NIR absorption, good biocompatibility, excellent PA contrast, and good photothermal conversion efficiency are reported. Real-time PA imaging of SLN reveals high resolution of the NPs via injection from the left forepaw pad. In addition, the surface functionalized NPs can target breast cancer cells and kill them efficiently and specifically through photothermal therapy upon 808 nm laser irradiation. This work shows great potential of the nanoparticle PA contrast agent to serve as a multifunctional probe for photothermal therapy at SLNs to achieve the inhibition of cancer cell metastasis in the near future.

Active Lymphatic Drainage From the Eye Measured by Noninvasive Photoacoustic Imaging of Near-Infrared Nanoparticles

“…50,53-58 Rare studies were able to quantify lymphatic drainage of intradermally injected nanoparticle contrast agents, such as gold nanocages 33 and oligomer nanoparticles, 35 to a peripheral node by photoacoustic imaging. Our approach to measuring ocular fluid drainage into the lymph nodes has multiple advantages.…”

“…Earlier work in skin lymphatics employed photoacoustic technology with a single element ultrasonic transducer that required longer scanning time to acquire a three-dimensional image. 33,35 In our study, the advanced photoacoustic tomography used a 128-element ultrasonic array, which allowed multispectral whole-body tomographic imaging with the capacity to separate the tracer signal from endogenous chromophores in the eye and lymph nodes. Furthermore, we used albumin, the most abundant natural plasma transport protein rather than oligomer nanoparticles 35 and gold nanocages 33 with unknown biocompatibility.…”

“…33,35 In our study, the advanced photoacoustic tomography used a 128-element ultrasonic array, which allowed multispectral whole-body tomographic imaging with the capacity to separate the tracer signal from endogenous chromophores in the eye and lymph nodes. Furthermore, we used albumin, the most abundant natural plasma transport protein rather than oligomer nanoparticles 35 and gold nanocages 33 with unknown biocompatibility. 59 Albumin as a tracer has been previously used to study lymphatic function 37 and to measure aqueous humor flow 60 and its drainage via conventional, and uveoscleral pathways, 60,61 including the uveolymphatic pathway.…”

“…23,26 Photoacoustic imaging has recently been used to map lymphatic drainage and spread of tumors to sentinel nodes using near-infrared contrast agents. [27][28][29][30][31][32][33][34][35] Even so, quantitative data have rarely been reported. 33,35 To our knowledge, there is no method available to measure lymph flow from the eye noninvasively.…”

“…[27][28][29][30][31][32][33][34][35] Even so, quantitative data have rarely been reported. 33,35 To our knowledge, there is no method available to measure lymph flow from the eye noninvasively. Here, for the first time, we detect and quantify lymphatic drainage from the mouse eye in the live state by photoacoustic tomography.…”