Materials Chemistry of Nanoultrasonic Biomedicine

Abstract

As a special cross-disciplinary research frontier, nanoultrasonic biomedicine refers to the design and synthesis of nanomaterials to solve some critical issues of ultrasound (US)-based biomedicine. The concept of nanoultrasonic biomedicine can also overcome the drawbacks of traditional microbubbles and promote the generation of novel US-based contrast agents or synergistic agents for US theranostics. Here, we discuss the recent developments of material chemistry in advancing the nanoultrasonic biomedicine for diverse US-based bio-applications. We initially introduce the design principles of novel nanoplatforms for serving the nanoultrasonic biomedicine, from the viewpoint of synthetic material chemistry. Based on these principles and diverse US-based bio-application backgrounds, the representative proof-of-concept paradigms on this topic are clarified in detail, including nanodroplet vaporization for intelligent/responsive US imaging, multifunctional nano-contrast agents for US-based multi-modality imaging, activatable synergistic agents for US-based therapy, US-triggered on-demand drug releasing, US-enhanced gene transfection, US-based synergistic therapy on combating the cancer and potential toxicity issue of screening various nanosystems suitable for nanoultrasonic biomedicine. It is highly expected that this novel nanoultrasonic biomedicine and corresponding high performance in US imaging and therapy can significantly promote the generation of new sub-discipline of US-based biomedicine by rationally integrating material chemistry and theranostic nanomedicine with clinical US-based biomedicine.

A Dual‐Model Imaging Theragnostic System Based on Mesoporous Silica Nanoparticles for Enhanced Cancer Phototherapy

“…To address these shortcomings, nanodroplets containing liquid perfluorocarbon (PFC) or perfluorohexane (PFH) have been recently developed, which are able to undergo a “liquid‐to‐gas” phase transformation in response to laser or high‐intensity US . This “small‐to‐large” strategy can integrate the advantages of NPs' tumor accumulation and MBs' high echogenic sensitivity, thus achieving intelligent and improved US imaging for cancer theranostics . Zheng's group developed PFH@PLGA/Fe 3 O 4 nanocapsules, which can transform PFH into MBs by the thermal effect of Fe 3 O 4 under NIR irradiation, thus achieving MRI/US imaging‐guided tumor photothermal therapy .…”

Gas‐Generating Nanoplatforms: Material Chemistry, Multifunctionality, and Gas Therapy

“…Therefore, they are only effective for ultrasonography within the blood vessel . One of the strategies to solve this critical issue is the fabrication of nanosized contrast agents for US imaging, but the small particle size in the range of nanometers has extremely low response to US, causing the poor echogenic sensitivity . Therefore, it is highly desirable to fabricate US contrast agents with the capability of simultaneous tumor penetration and desirable US‐imaging contrast.…”

“…The droplet vaporization is one of the most representative strategies for achieving the desirable US imaging, which originates from the concept of “small‐to‐big” transformation . Typically, acoustic droplet vaporization (ADV), optical droplet vaporization (ODV), and magnetic droplet vaporization (MDV) are the three representative strategies for achieving externally triggered US imaging ( Figure ).…”

A Yolk–Shell Nanoplatform for Gene‐Silencing‐Enhanced Photolytic Ablation of Cancer

“…However, some drawbacks such as the hyperthermia to normal tissues induced by high power density laser and the low therapeutic effects caused by instability of most photosensitizers largely restrict the development of these two modalities . Recently, an interesting strategy of optical droplet vaporization has been proposed to construct NIR light responsive cancer treatment platform . Instead of producing heat or reactive oxygen, plenty of gas microbubbles are generated under laser irradiation in this system.…”