Ultrasound-Triggered Delivery of Iproplatin from Microbubble-Conjugated Liposomes

Microfluidic fabrication of monodisperse microcapsules with gas cores

A facile strategy for efficient and continuous fabrication of monodisperse gas-core microcapsules with controllable sizes and excellent ultrasound-induced burst performances is developed based on droplet microfluidics and interfacial polymerization. Monodisperse gas-in-oil-in-water (G/O/W) double emulsion droplets with a gas core and monomer-contained oil layer are fabricated in the upstream of a microfluidic device as templates, and then water-soluble monomers are added into the aqueous continuous phase in the downstream to initiate rapid interfacial polymerization at the O/W interfaces to prepare monodisperse gas-in-oil-in-solid (G/O/S) microcapsules with gas cores. The sizes of both microbubbles and G/O/W droplet templates can be precisely controlled by adjusting the gas supply pressure and the fluid flow rates. Due to the very thin shells of G/O/S microcapsules fabricated via interfacial polymerization, the sizes of the resultant G/O/S microcapsules are almost the same as those of the G/O/W droplet templates, and the microcapsules exhibit excellent deformable properties and ultrasound-induced burst performances. The proposed strategy provides a facile and efficient route for controllably and continuously fabricating monodisperse microcapsules with gas cores, which are highly desired for biomedical applications.

Fabrication and Evaluation of Ultrasound-Responsive Emulsion Loading Paclitaxel for Targeted Chemotherapy

Chemotherapy is the most widely used cancer treatment, but it has several drawbacks such as adverse side effects and low bioavailability. To address these limitations, various drug delivery systems have been investigated, including liposomes, micelles, and emulsions. These drug delivery technologies have been improving the efficacy and safety of conventional chemotherapy. This study presents an emerging drug delivery technology for targeted chemotherapy using drug-loaded ultrasound-responsive emulsion (URE) as a drug carrier and ultrasound technology for external activation. URE was designed to be responsive to ultrasound energy and fabricated by using an emulsification technique. To investigate this technology, paclitaxel, as a model drug, was used and encapsulated into URE. The size distribution, morphology, and drug release behavior of paclitaxel-loaded URE (PTX-URE) were characterized, and the echogenicity of PTX-URE was assessed by using ultrasound imaging equipment. The cellular uptake and cytotoxicity of PTX-URE with ultrasound were evaluated in breast cancer cells (MDA-MB-231). Our in vitro results indicate that the combination of PTX-URE and ultrasound significantly enhanced cellular uptake by 10.6-fold and improved cytotoxicity by 24.1% compared to PTX alone. These findings suggest that the URE platform combined with ultrasound is a promising technology to improve the drug delivery efficiency for chemotherapy.

Evaluation of Doxorubicin-loaded Echogenic Macroemulsion for Targeted Drug Delivery

BACKGROUND

The latest technology trend in targeted drug delivery highlights stimuliresponsive particles that can release an anticancer drug in a solid tumor by responding to external stimuli.

OBJECTIVE

This study aims to design, fabricate, and evaluate an ultrasound-responsive drug delivery vehicle for an ultrasound-mediated drug delivery system.

METHODS

The drug-containing echogenic macroemulsion (eME) was fabricated by an emulsification method using the three phases (aqueous lipid solution as a shell, doxorubicin (DOX) contained oil, and perfluorohexane (PFH) as an ultrasound-responsive agent). The morphological structure of eMEs was investigated using fluorescence microscopy, and the size distribution was analyzed by using DLS. The echogenicity of eME was measured using a contrast-enhanced ultrasound device. The cytotoxicity was evaluated using a breast cancer cell (MDA-MB-231) via an in vitro cell experiment.

RESULTS

The obtained eME showed an ideal morphological structure that contained both DOX and PFH in a single particle and indicated a suitable size for enhancing ultrasound response and avoiding complications in the blood vessel. The echogenicity of eME was demonstrated via an in vitro experiment, with results showcasing the potential for targeted drug delivery. Compared to free DOX, enhanced cytotoxicity and improved drug delivery efficiency in a cancer cell were proven by using DOX-loaded eMEs and ultrasound.

CONCLUSION

This study established a platform technology to fabricate the ultrasound-responsive vehicle. The designed drug-loaded eME could be a promising platform with ultrasound technology for targeted drug delivery.

The role of acoustofluidics and microbubble dynamics for therapeutic applications and drug delivery

Targeted drug delivery is proposed to reduce the toxic effects of conventional therapeutic methods. For that purpose, nanoparticles are loaded with drugs called nanocarriers and directed toward a specific site. However, biological barriers challenge the nanocarriers to convey the drug to the target site effectively. Different targeting strategies and nanoparticle designs are used to overcome these barriers. Ultrasound is a new, safe, and non-invasive drug targeting method, especially when combined with microbubbles. Microbubbles oscillate under the effect of the ultrasound, which increases the permeability of endothelium, hence, the drug uptake to the target site. Consequently, this new technique reduces the dose of the drug and avoids its side effects. This review aims to describe the biological barriers and the targeting types with the critical features of acoustically driven microbubbles focusing on biomedical applications. The theoretical part covers the historical developments in microbubble models for different conditions: microbubbles in an incompressible and compressible medium and bubbles encapsulated by a shell. The current state and the possible future directions are discussed.

Characterization of PDL1 enhanced siRNA/albumin liposome for effective therapeutic function in lung cancer

PURPOSE

The applications of liposomes are limited due to poor structural stability and short drug circulation time. This study aims to build an albumin-based liposomal delivery system to provide strategies for tumor specificity, efficient gene delivery and effective release of albumin liposomes.

METHODS

In this study, siRNA loaded PDL1-targeted albumin liposome was constructed for the treatment of lung cancer and its function was evaluated. Physical parameters such as particle size, potential and infrared spectrum were detected and microscopic morphology was observed by electron microscopy to detect the binding and uptake capacity of albumin liposome with cells. The optimal preparation process and binding ratio of PDL1-targeted albumin liposome/siRNA complex were determined.

RESULTS

The constructed siRNA loaded PDL1-targeted albumin liposomes has low toxicity, high loading rate and tumor cell targeted gene therapy ability. Moreover, it increased T cell activation and down-regulated siRNA expression, effectively realizing the inhibition of lung cancer cells.

CONCLUSION

The results showed that the PDL1-targeted albumin liposome could be used as a high efficient delivery vector of siRNA, and was a high efficient and safe nano vector for tumor targeted gene therapy.