Acoustic-Based Theranostic Probes Activated by Tumor Microenvironment for Accurate Tumor Diagnosis and Assisted Tumor Therapy

Abstract

Acoustic-based imaging techniques, including ultrasonography and photoacoustic imaging, are powerful noninvasive approaches for tumor imaging owing to sound transmission facilitation, deep tissue penetration, and high spatiotemporal resolution. Usually, imaging modes were classified into "always-on" mode and "activatable" mode. Conventional "always-on" acoustic-based probes often have difficulty distinguishing lesion regions of interest from surrounding healthy tissues due to poor target-tobackground signal ratios. As compared, activatable probes have attracted attention with improved sensitivity, which can boost or amplify imaging signals only in response to specific biomolecular recognition or interactions. The tumor microenvironment (TME) exhibits abnormal physiological conditions that can be used to identify tumor sections from normal tissues. Various types of organic dyes and biomaterials can react with TME, leading to obvious changes in their optical properties. The TME also affects the selfassembly or aggregation state of nanoparticles, which can be used to design activatable imaging probes. Moreover, acoustic-based imaging probes and therapeutic agents can be coencapsulated into one nanocarrier to develop nanotheranostic probes, achieving tumor imaging and cooperative therapy. Satisfactorily, ultrasound waves not only accelerate the release of encapsulated therapeutic agents but also activate therapeutic agents to exert or enhance their therapeutic performance. Meanwhile, various photoacoustic probes can convert photon energy into heat under irradiation, achieving photoacoustic imaging and cooperative photothermal therapy. In this review, we focus on the recently developed TME-triggered ultrasound and photoacoustic theranostic probes for precise tumor imaging and targeted tumor therapy.

Theranostic Fluorescent Probes

“…When they enter the tumor microenvironment, the therapeutic probes are activated to produce imaging signals with high signal-to-noise ratios, and high sensitivity. 468 In order to improve the efficacy of SDT, theranostic fluorescence probes are necessary to enable an accurate clinical judgment by physicians. Small molecule drugs loaded on nanoplatforms can realize the purpose of precise tumor localization.…”

A copper-loaded self-assembled nanoparticle for disturbing the tumor redox balance and triple anti-tumor therapy

“…The tumor-bearing mice were randomly divided into six groups with three mice in each group. The corresponding drugs were injected on the 1st, 4th, 7th and 10th days respectively: (1)…”

“…Cancer remains a serious condition affecting human health worldwide. [1][2][3] Conventional cancer therapies, such as surgery, chemotherapy, and radiotherapy display limited therapeutic effects and often lead to severe side effects. 4,5 Recently, novel emerging strategies, including photodynamic therapy (PDT), sonodynamic therapy (SDT) and chemodynamic therapy (CDT), have been significantly applied in precise cancer therapy due to their relatively low toxicity toward normal cells.…”

The Three Laws of Nano-Robotics

“…But enhancing an image is just one of many sensory features that have been incorporated into nanoparticles. A major focus of ACS Sensors is on incorporating chemical or biochemical sensors into nanoparticles. − While many of these more sophisticated sensing features emphasize in vivo applications, many others focus on applications outside the body, such as in the laboratory, ,, or the clinical setting. ,− The term “theranostics” refers to a linking of a diagnostic product with a pharmaceutical treatment, and theranostic nanoparticles try to couple the nanosensing systems with nanotherapeutics, combining the surveillance and the warhead functions into a single entity . Such integration represents one of the major challenges of nanotechnology today.…”

“…33,37−39 The term "theranostics" refers to a linking of a diagnostic product with a pharmaceutical treatment, 40 and theranostic nanoparticles try to couple the nanosensing systems with nanotherapeutics, combining the surveillance and the warhead functions into a single entity. 30 Such integration represents one of the major challenges of nanotechnology today.…”