Polymer‐based activatable optical probes for tumor fluorescence and photoacoustic imaging

Abstract

Optical imaging including fluorescence imaging and photoacoustic imaging have been widely employed in early and accurate diagnosis of cancer. Compared to the “always on” optical probes, the molecular probes that could emit their signal in response to the tumor microenvironment exhibit the low background noise and high signal‐to‐background ratio, allowing sensitive and accurate cancer diagnosis. Polymer‐based activatable optical probes display the advantages of improved water solubility, good photostability, extended blood circulation time, and easy functionalization, which enable them to accumulate in tumor for early and accurate diagnosis. This review focuses on recent advances in the development of polymer‐based activatable optical probes for tumor fluorescence and PA imaging. The designs of polymer‐based optical probes are first discussed. Then the applications for tumor fluorescence and PA imaging using pH, hypoxia, reactive oxygen and nitrogen species, and enzymes responsive polymer‐based optical probes are discussed in details. At last, the present challenges and perspectives of polymer‐based activatable optical probes to further advance them into the clinical application are also suggested. This article is categorized under: Diagnostic Tools > In vivo Nanodiagnostics and Imaging Diagnostic Tools > Biosensing

Activatable Optical Probes for Fluorescence and Photoacoustic Imaging of Drug‐Induced Liver Injury

“…Optical imaging techniques, including fluorescence imaging (FLI) and photoacoustic imaging (PAI), can provide the visualization of physiological or pathological processes of various diseases at the molecular level in living organisms due to their high sensitivity and high spatiotemporal resolution. [11][12][13][14][15][16][17][18] To visualize molecular status or biological events in living organisms, optical probes are essential. [19][20][21][22] In particular, activatable optical probes that generate significant signal changes in response to a specific biomarker or stimuli have attracted much attention in the disease diagnosis field.…”

Intelligent Tumor Microenvironment-Activated Multifunctional Nanoplatform Coupled with Turn-on and Always-on Fluorescence Probes for Imaging-Guided Cancer Treatment

“…30 In contrast, the readout signal of the tumor-responsive probes can be specifically activated by the tumor-related targets (such as TME) to accurately monitor the dynamic variations in tumors for the guidance of the treatment process and the evaluation of the therapeutic efficacy. 31,32 Nevertheless, the tumor-responsive probes are incapable of tracking the real-time distribution of the material in the systemic normal tissue for the biosafety assessment on account of the inactive off-state. Therefore, the combination of tumor-activated and always-on fluorescence imaging plays an important role in monitoring the dynamic distribution of nanoplatforms in tumor and physiological systems.…”

“…Currently, imaging-guided theranostic nanosystems have garnered tremendous interest for simultaneously monitoring drug distribution and treatment processes in tumors. − Inorganic nanoparticles with superior optical characteristics, such as Au, quantum dots, CuS, upconversion nanoparticles, etc., have been extensively applied for imaging-guided therapy. − However, intricate and complex procedures were demanded to incorporate therapeutics into these nanoparticles for the lack of active binding sites. , Moreover, a majority of imaging-guided therapeutic nanoplatforms consists of “always-on” probes, which track the biodistribution of nanomaterials independent of the tumor-related factors, resulting in the nontumor-specific imaging . In contrast, the readout signal of the tumor-responsive probes can be specifically activated by the tumor-related targets (such as TME) to accurately monitor the dynamic variations in tumors for the guidance of the treatment process and the evaluation of the therapeutic efficacy. , Nevertheless, the tumor-responsive probes are incapable of tracking the real-time distribution of the material in the systemic normal tissue for the biosafety assessment on account of the inactive off-state. Therefore, the combination of tumor-activated and always-on fluorescence imaging plays an important role in monitoring the dynamic distribution of nanoplatforms in tumor and physiological systems.…”

A bioactivated in vivo assembly (BIVA) nanotechnology fabricated NIR probe for small pancreatic tumor intraoperative navigation imaging

“…[11] For a better speci city, researchers developed tumor microenvironment turn-on probe to response ROS, lack of oxygen, pH etc. [14][15][16] However, traditional small molecule uorescent dyes metabolize quickly and are easy to be removed by liver and kidney, which shortens the imaging detection time. [17] Secondly, the aggregation-caused quenching (ACQ) effect of such uorescence dyes limited the molecule accumulation in tumor and the photobleaching behavior also confused the imaging.…”