Combination of microfluidic chip and electrostatic atomization for the preparation of drug-loaded core-shell nanoparticles

Coaxial electrostatic spray-based preparation of localization missile liposomes on a microfluidic chip for targeted treatment of triple-negative breast cancer

Due to triple-negative breast cancer (TNBC) lacking specific targets for efficient therapies, nanoparticles have been widely developed to enhance efficacy and reduce the toxicity of chemotherapeutics. We prepared unique liposomes containing PTX and DOX by microfluidics-based coaxial electrostatic spray method, which have a uniform particle size, high drug loading capacity, and good stability. Meanwhile, the cRGD peptide was fused with the lipid membrane to form PTX/DOX@cRGD-Lipo, which played a GPS role in locating tumor neovascularization and further targeting TNBC cells where both overexpress αvβ3. The PTX/DOX@cRGD-Lipo showed synergistic anti-tumor activity of double drugs and enhanced tumor cell apoptosis. Fluorescence microscopy and flow cytometry showed that the co-loaded targeted liposomes could be effectively absorbed by MDA-MB-231 and 4T1 cells and then released the content. In addition, the PTX/DOX@cRGD-Lipo presented excellent targeting biodistribution in vivo and a higher tumor growth inhibition rate in the orthotopic tumor mouse model. All results suggested that the double drug-loaded targeted liposome could be a promising treatment modality for TNBC.

The recent insight in the release of anticancer drug loaded into PLGA microspheres

Cancer is a series of diseases leading to a high rate of death worldwide. Microspheres display specific characteristics that make them appropriate for a variety of biomedical purposes such as cancer therapy. Newly, microspheres have the potentials to be used as controlled drug release carriers. Recently, PLGA-based microspheres have attracted exceptional attention relating to effective drug delivery systems (DDS) because of their distinctive properties for a simple preparation, biodegradability, and high capability of drug loading which might be increased drug delivery. In this line, the mechanisms of controlled drug release and parameters that influence the release features of loaded agents from PLGA-based microspheres should be mentioned. The current review is focused on the new development of the release features of anticancer drugs, which are loaded into PLGA-based microspheres. Consequently, future perspective and challenges of anticancer drug release from PLGA-based microspheres are mentioned concisely.

Progress in the application of sustained-release drug microspheres in tissue engineering

Sustained-release drug-loaded microspheres provide a long-acting sustained release, with targeted and other effects. There are many types of sustained-release drug microspheres and various preparation methods, and they are easy to operate. For these reasons, they have attracted widespread interest and are widely used in tissue engineering and other fields. In this paper, we provide a systematic review of the application of sustained-release drug microspheres in tissue engineering. First, we introduce this new type of drug delivery system (sustained-release drug carriers), describe the types of sustained-release drug microspheres, and summarize the characteristics of different microspheres. Second, we summarize the preparation methods of sustained-release drug microspheres and summarize the materials required for preparing microspheres. Third, various applications of sustained-release drug microspheres in tissue engineering are summarized. Finally, we summarize the shortcomings and discuss future prospects in the development of sustained-release drug microspheres. The purpose of this paper was to provide a further systematic understanding of the application of sustained-release drug microspheres in tissue engineering for the personnel engaged in related fields and to provide inspiration and new ideas for studies in related fields.

Microfluidic Nanoparticles for Drug Delivery

Nanoparticles (NPs) have attracted tremendous interest in drug delivery in the past decades. Microfluidics offers a promising strategy for making NPs for drug delivery due to its capability in precisely controlling NP properties. The recent success of mRNA vaccines using microfluidics represents a big milestone for microfluidic NPs for pharmaceutical applications, and its rapid scaling up demonstrates the feasibility of using microfluidics for industrial-scale manufacturing. This article provides a critical review of recent progress in microfluidic NPs for drug delivery. First, the synthesis of organic NPs using microfluidics focusing on typical microfluidic methods and their applications in making popular and clinically relevant NPs, such as liposomes, lipid NPs, and polymer NPs, as well as their synthesis mechanisms are summarized. Then, the microfluidic synthesis of several representative inorganic NPs (e.g., silica, metal, metal oxide, and quantum dots), and hybrid NPs is discussed. Lastly, the applications of microfluidic NPs for various drug delivery applications are presented.

Application of CFD Numerical Simulation Image Imaging Technology in the Study of Droplet Microfluidic Multiphase Flow Characteristics

In order to study the problem that the flow in the internal channel of the microfluidic chip is different from that of the macroscopic system by the FD numerical simulation image imaging technology. Taking the liquid-liquid extraction of microfluidic chip as the research object, this paper analyzes the theoretical basis, working principle, structural parameters, and the influence of working parameters on the fluid flow of liquid-liquid extraction. The results are as follows: when the inlet velocity of flowing liquid is 10^{^(-5)} m/s, the diffusion efficiency can still be maintained at 95%; the double ψ-type aqueous phase showed laminar flow, the two-phase contact interface increased compared with the bottom flow rate, and the extraction efficiency increased to 98%; the extraction efficiency of double ψ type is higher than that of double Y-type: when the flow velocity ratio increases from v _aq : v _oil=1 : 2 to v _aq : v _oil=5 : 1, the extraction efficiency increases to 99.8%; the experimental extraction efficiency is compared with the diffusion efficiency simulated by simulation. The diffusion efficiency of the cross type is 1.05 times that of the extraction efficiency, and that of the cylindrical type is 1.04 times that of the extraction efficiency. In this study, CFD is used to simulate the characteristics of droplet microfluidic multiphase flow, which enriches the theoretical method and research experience of liquid-liquid laminar flow.

Atomization Characteristics of Hydrogen Peroxide Solutions in Electrostatic Field

Hydrogen peroxide (H₂O₂) can be considered as a sterilant or a green propellant. For a common use in industrial application, spray is an effective method to form fine H₂O₂ droplets. In this paper, electrostatic atomization based on the configuration of needle ring electrodes is proposed to produce H₂O₂ spray by minimizing its effective surface tension. The breakup performances of H₂O₂ ligaments can be improved by increasing the electric field intensity, reducing the nozzle size, and adjusting suitable volume flow rate. The smallest average diameter of breakup droplets for 35 wt. % concentration H₂O₂ solution reached 92.8 μm under optimum operation conditions. The H₂O₂ concentration significantly influenced the breakup performance owing to the concentration effect on comprehensive physical properties such as density, surface tension, viscosity, and permittivity. The average diameters of breakup droplets decreased with decreasing H₂O₂ concentration. At 8 wt. % concentration, the average breakup droplet diameter was reduced to 67.4 μm. Finally, electrostatic atomization mechanism of H₂O₂ solution was analyzed by calculating dimensionless parameters of Re, We, and Oh numbers with the combination of the operation conditions and physical properties for in-depth understanding the breakup behaviors. The calculation showed that the minimum average diameter of breakup droplets was obtained at 8 wt. % concentration at the investigated range of H₂O₂ concentration, which kept in agreement with the experimental results.

PLGA sustained-release microspheres loaded with an insoluble small-molecule drug: microfluidic-based preparation, optimization, characterization, and evaluation in vitro and in vivo

Microspheres play an important role in controlling drug delivery and release rate accurately. To realize the sustainable release of insoluble small-molecule drugs, a new three-phase flow-focusing microfluidic device was developed to produce the drug-loaded sustained-release microspheres which were prepared with bicalutamide (BCS class-II) as the model drug and poly(lactide-co-glycolide) (PLGA) as the carrier material. Under optimized prescription conditions, the microspheres showed a smooth surface and uniform size of 51.33 μm with a CV value of 4.43%. Sustained-release microspheres had a releasing duration of around 40 days in vitro without any initial burst release. The drug release mechanism of the microspheres was drug diffusion and polymer erosion. Meanwhile, the drug release of microspheres in vivo could be up to 30 days. Briefly, the microfluidic device in this study provides a new solution for the preparation of sustained-release microspheres for insoluble small-molecule drugs. PLGA sustained-release microspheres developed by the microfluidic device have good application prospects in precise delivery and sustainable release of insoluble small-molecule drugs.

Droplet Microfluidics for Tumor Drug-Related Studies and Programmable Artificial Cells

Anticancer drug development is a crucial step toward cancer treatment, that requires realistic predictions of malignant tissue development and sophisticated drug delivery. Tumors often acquire drug resistance and drug efficacy, hence cannot be accurately predicted in 2D tumor cell cultures. On the other hand, 3D cultures, including multicellular tumor spheroids (MCTSs), mimic the in vivo cellular arrangement and provide robust platforms for drug testing when grown in hydrogels with characteristics similar to the living body. Microparticles and liposomes are considered smart drug delivery vehicles, are able to target cancerous tissue, and can release entrapped drugs on demand. Microfluidics serve as a high-throughput tool for reproducible, flexible, and automated production of droplet-based microscale constructs, tailored to the desired final application. In this review, it is described how natural hydrogels in combination with droplet microfluidics can generate MCTSs, and the use of microfluidics to produce tumor targeting microparticles and liposomes. One of the highlights of the review documents the use of the bottom-up construction methodologies of synthetic biology for the formation of artificial cellular assemblies, which may additionally incorporate both target cancer cells and prospective drug candidates, as an integrated "droplet incubator" drug assay platform.

PLGA-based biodegradable microspheres in drug delivery: recent advances in research and application

Biodegradable microspheres have been widely used in the field of medicine due to their ability to deliver drug molecules of various properties through multiple pathways and their advantages of low dose and low side effects. Poly (lactic-co-glycolic acid) copolymer (PLGA) is one of the most widely used biodegradable material currently and has good biocompatibility. In application, PLGA with a specific monomer ratio (lactic acid and glycolic acid) can be selected according to the properties of drug molecules and the requirements of the drug release rate. PLGA-based biodegradable microspheres have been studied in the field of drug delivery, including the delivery of various anticancer drugs, protein or peptide drugs, bacterial or viral DNA, etc. This review describes the basic knowledge and current situation of PLGA biodegradable microspheres and discusses the selection of PLGA polymer materials. Then, the preparation methods of PLGA microspheres are introduced, including emulsification, microfluidic technology, electrospray, and spray drying. Finally, this review summarizes the application of PLGA microspheres in drug delivery and the treatment of pulmonary and ocular-related diseases.

Microfluidics for core-shell drug carrier particles - a review

Core-shell drug-carrier particles are known for their unique features. Due to the combination of superior properties not exhibited by the individual components, core-shell particles have gained a lot of interest. The structures could integrate core and shell characteristics and properties. These particles were designed for controlled drug release in the desired location. Therefore, the side effects would be minimized. So, these particles' advantages have led to the introduction of new methods and ideas for their fabrication. In the past few years, the generation of drug carrier core-shell particles in microfluidic chips has attracted much attention. This method makes it possible to produce particles at nanometer and micrometer levels of the same shape and size; it usually costs less than other methods. The other advantages of using microfluidic techniques compared to conventional bulk methods are integration capability, reproducibility, and higher efficiency. These advantages have created a positive outlook on this approach. This review gives an overview of the various fluidic concepts that are used to generate microparticles or nanoparticles. Also, an overview of traditional and more recent microfluidic devices and their design and structure for the generation of core-shell particles is given. The unique benefits of the microfluidic technique for core-shell drug carrier particle generation are demonstrated.