Thermoacoustic Imaging and Therapy Guidance based on Ultra-short Pulsed Microwave Pumped Thermoelastic Effect Induced with Superparamagnetic Iron Oxide Nanoparticles

Abstract

Multifunctional nanoparticle-mediated imaging and therapeutic techniques are promising modalities for accurate localization and targeted treatment of cancer in clinical settings. Thermoacoustic (TA) imaging is highly sensitive to detect the distribution of water, ions or specific nanoprobes and provides excellent resolution, good contrast and superior tissue penetrability. TA therapy is a potential non-invasive approach for the treatment of deep-seated tumors. In this study, human serum albumin (HSA)-functionalized superparamagnetic iron oxide nanoparticle (HSA-SPIO) is used as a multifunctional nanoprobe with clinical application potential for MRI, TA imaging and treatment of tumor. In addition to be a MRI contrast agent for tumor localization, HSA-SPIO can absorb pulsed microwave energy and transform it into shockwave via the thermoelastic effect. Thereby, the reconstructed TA image by detecting TA signal is expected to be a sensitive and accurate representation of the HSA-SPIO accumulation in tumor. More importantly, owing to the selective retention of HSA-SPIO in tumor tissues and strong TA shockwave at the cellular level, HSA-SPIO induced TA effect under microwave-pulse radiation can be used to highly-efficiently kill cancer cells and inhibit tumor growth. Furthermore, ultra-short pulsed microwave with high excitation efficiency and deep penetrability in biological tissues makes TA therapy a highly-efficient anti-tumor modality on the versatile platform. Overall, HSA-SPIO mediated MRI and TA imaging would offer more comprehensive diagnostic information and enable dynamic visualization of nanoagents in the tumorous tissue thereby tumor-targeted therapy.

Thermo-Sensitive Nanomaterials: Recent Advance in Synthesis and Biomedical Applications

“…The shockwaves produced by the thermal expansion can be acquired by an ultrasound transducer and reconstructed to form TA images. Wen and collaborators have recently studied human serum albumin (HSA) functionalized superparamagnetic iron oxide nanoparticles (HSA-SPIO) as a theranostic nanosystem with potential application for MRI, TA imaging, and treatment of tumors [ 196 ]. The authors intravenously injected HSA-SPIO in 4T1 tumor-bearing mice that were localized by MRI.…”

“…( c ) HSA-SPIO as a TA therapeutic agent for tumor therapy. Reproduced with permission from [ 196 ]. Copyright Ivyspring International Publisher, 2017.…”

Precise Tumor Photothermal Therapy Guided and Monitored by Magnetic Resonance/Photoacoustic Imaging using A Safe and pH‐Responsive Fe(III) Complex

“…[1][2][3] Therefore, it's still urgent to develop alternative cancer treatment modalities with high efficacy and low side effects. In recent years, innovative treatment approaches, such as microwave therapy, radiofrequency therapy, ultrasound therapy, and phototherapy have attracted increasing interest [4][5][6][7][8] Among them, phototherapy modalities have received the most attention owing to their high efficiency, spatial specificity, noninvasive or minimally invasive feature, and remote control capability. [9,10] In particular, photothermal therapy (PTT), which relies on converting light energy into heat via irradiation of photothermal agents (PTAs), is an attractive and non-invasive technique for treating cancers.…”

Remotely Activated Nanoparticles for Anticancer Therapy

“…A possibility is to employ nanomaterials that, in synergy with MWs, improve the temperature absorbing energy [ 21 ] and may promote a Joule heating effect [ 92 ]. Additionally, it is reported that some nanotools, e.g., iron oxide NPs and carbon nanotubes, are able to produce shock waves under a MW input, provoking a mechanical stimulation of the cells [ 93 , 94 ]. The presence of these NPs moreover tunes both the thermal and electrical conductivities of the tissue, increasing the thermal ablation efficiency [ 95 ], but the operating mechanism is still unclear [ 96 ].…”