Magnetic-, Acoustic-, and Optical-Triple-Responsive Microbubbles for Magnetic Hyperthermia and Pothotothermal Combination Cancer Therapy

Summary

Presented here is a protocol for the fabrication of iron oxide nanoparticle-shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform for magnetic hyperthermia and photothermal combination cancer therapy.

Abstract

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has been challenged. Here, we fabricate iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. Iron oxide nanoparticles serve as both magnetic and photothermal agents. Once intravenously injected, NSMs can be magnetically guided to the tumor site. Ultrasound triggers the release of iron oxide nanoparticles, facilitating the penetration of nanoparticles deep into the tumor due to the cavitation effect of microbubbles. Thereafter, magnetic hyperthermia and photothermal therapy can be performed on the tumor for combinational cancer therapy, a solution for cancer resistance due to the tumor heterogeneity. In this protocol, the synthesis and characterization of NSMs including structural, chemical, magnetic and acoustic properties were performed. In addition, the anti-cancer efficacy by thermal therapy was investigated using in vitro cell cultures. The proposed delivery strategy and combination therapy holds great promise in cancer treatment to improve both delivery and anticancer efficacies.

Introduction

Cancer is one of the deadliest diseases, causing millions of deaths every year worldwide and huge economic losses¹. In clinics, conventional anticancer therapies, such as surgical resection, radiotherapy, and chemotherapy still cannot provide a satisfactory therapeutic efficacy². Limitations of these therapies are high toxic side effects, high recurrence rate and high metastasis rate³. For example, chemotherapy is suffered from the low delivery efficiency of chemo drugs precisely to the tumor site⁴. The inability of drugs to penetrate deep into the tumor tissue across the b....

Protocol

All animal experiments were performed in accordance with the protocols approved by the OG Pharmaceutical guidelines for Animal Care and Use of Laboratory Animals. The protocols followed the guidelines of Ethics Committee for laboratory animals of OG Pharmaceutical.

1. Nanoparticle shelled microbubbles (NSMs) synthesis

1. Disperse magnetic nanoparticles (Fe₃O₄, iron oxide) in deionized water to form a 10 mg/mL stock solution.
2. Place the tube containing the IONPs solution in an ultrasonic cleaning machine for 20 min. Obtain a uniformly dispersed IONPs solution before use.
3. Add 150 μL of de....

Results

The triple-responsive nanoparticle-shelled microbubbles (NSMs) used in this study were prepared by agitating the mixture of the surfactant and IONPs. The IONPs (50 nm) self-assembled at the interface of liquid and gas core, to form a densely packed magnetic shell. The morphology of NSMs is shown in Figure. 1A. The resulted NSMs presented a spherical shape and with an average diameter of 5.41 ± 1.78 μm (Figure 1B). The results indicated the NSMs were prepared successfully. When stored in .......

Discussion

Here, we presented a protocol of fabricating iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. The IONPs were densely packed around the air core to form a magnetic shell, which can be controlled by the external magnetic field for targeting. Once delivered, the release of IONPs can be achieved by ultrasound trigger. The released IONPs can be activated by both NIR light and AFM for PTT and MHT, or the combin.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
808 nm laser power	Changchun New Industries Optoelectronics Tech	MDL-F-808-5W-18017023
Calcein-AM	Thermo Fisher SCIENTIFIC	C3099
Fetal bovine serum	Invitrogen	16000-044
Fluorescence Microscope	Olympus	IX71
Function generator	Keysight	33500B series	20 MHz, 2 channels with arbitrary waveform generation capability
Gelatin gel	Sigma	9000-70-8
Heating machine	Shuangping	SPG-06- II
Homemade focused transducer			Frequency=855, R-X=36.2W+5.8W, |Z|-θ=37W+8°
Homogenizer	SCILOGEX	D-160	8000-30000 rpm
Hydrophone	T&C	NH1000
ICR male mice	OG Pharmaceutical. Co. Ltd		8-week-old
Inductively coupled plasma optical emission spectrometry	PerkinElmer
Infrared thermal imaging camera.	FLIR	E50
Iron(II,III) oxide	Alfa Aesar	1317-61-9	50-100nm APS Powder
Laser power meter	Changchun New Industries Optoelectronics Tech
Oscilloscope	Keysight	DSOX3054T	Bandwidth 500 MHz, Sampling Rate 5 GS/S, 4 channels
RF Power Amplifier	T&C	AG1020	The signal source can also be connected to an external signal source. The gain can be adjusted from 0 to 100%. It has multiple functions such as frequency sweep, pulse, and triangle.
Roswell Park Memorial Institute-1640	KeyGEN BioTECH	KGM31800
Sodium dodecyl sulfate	Sigma	151-21-3