Semiconducting polymer nanoparticles as photoacoustic molecular imaging probes in living mice

Abstract

Photoacoustic (PA) imaging holds great promise for the visualization of physiology and pathology at the molecular level with deep tissue penetration and fine spatial resolution. To fully utilize this potential, PA molecular imaging probes have to be developed. Herein we introduce near infrared (NIR) light absorbing semiconducting polymer nanoparticles (SPNs) as a new class of contrast agents for PA molecular imaging. SPNs can produce stronger signal than commonly used single-wall carbon nanotubes and gold nanorods on a per mass basis, permitting whole-body lymph node PA mapping in living mice at a low systematic injection mass. Furthermore, SPNs possess high structural flexibility, narrow PA spectral profiles, and strong resistance to photodegradation and oxidation, which enables development of the first NIR ratiometric PA probe for in vivo real-time imaging of reactive oxygen species—vital chemical mediators of many diseases. These results demonstrate SPNs an ideal nanoplatform for developing PA molecular probes.

H 2 O 2 -responsive liposomal nanoprobe for photoacoustic inflammation imaging and tumor theranostics via in vivo chromogenic assay

“…For example, many types of nanoparticles with strong and constant NIR absorbance are often used for enhanced blood pool imaging and PA imaging of tumors (15,16,19). In addition, smart PA imaging nanoprobes with their absorbance spectra responsive to certain physiological signals such as reactive oxygen species (ROS), pH, and enzymes have also received substantial interest in recent years (12,21,22), because such a type of imaging would provide critical information directly related to disease progression and mechanisms. However, a sensitive and biocompatible nanoprobe that can precisely detect H 2 O 2 in vivo by PA imaging has not yet been reported, to our best knowledge.…”

Multiplexed imaging for diagnosis and therapy

“…However, the customisable structure and composition of nanomaterials have motivated their status as perhaps the most 'engineerable' platforms for PAI, particularly for integrating photoacoustic imaging with MRI, OI and therapeutic strategies. Recent years have witnessed the successful application of approaches involving metal-based (nanoparticles, nanorods, nanoshells and nanocages) and carbon-based (carbon dots, nanotubes, nanopolymers and nanovesicles) nanomaterials for targeting cell-specific antigens or the microenvironment (pH, pO2 sensing), or for passive targeting (that is, by taking advantage of the enhanced permeability and retention effect) in PAI 94,[99][100][101][102][103][104][105][106] . Although PAI is limited by tissue-penetration depth of the requisite excitation light, its clinical outlook is terrific for the early detection and monitoring of superficial or near-surface lesions, as well as those accessible via endoscopy.…”

Polymeric nanoparticles: Recent development in synthesis and application

“…Also, the plasticizing effectiveness of PNPs was lower than that of PCE, which should be owing to their larger particle size and thicker adsorption layer on the surface of cement. Pu et al [91] introduced semiconducting PNPs (SPNs) as near-infrared photoacoustic contrast agents for photoacoustic molecular imaging. They selected poly(cyclopentadithio- Figure 12.…”