Development of a bio-electrospray system for cell and non-viral gene delivery

Recent advances of electrospray technique for multiparticulate preparation: Drug delivery applications

The electrospray (ES) technique has proven to be an effective and a versatile approach for crafting drug delivery carriers with diverse dimensions, multiple layers, and varying morphologies. Achieving the desired particle properties necessitates careful optimization of various experimental parameters. This review delves into the most prevalent ES system configurations employed for this purpose, such as monoaxial, coaxial, triaxial, and multi-needle setups with solid or liquid collector. In addition, this work underscores the significance of ES in drug delivery carriers and its remarkable ability to encapsulate a wide spectrum of therapeutic agents, including drugs, nucleic acids, proteins, genes and cells. Depth examination of the critical parameters governing the ES process, including the choice of polymer, surface tension, voltage settings, needle size, flow rate, collector types, and the collector distance was conducted with highlighting on their implications on particle characteristics, encompassing morphology, size distribution, and drug encapsulation efficiency. These insights illuminate ES's adaptability in customizing drug delivery systems. To conclude, this review discusses ES process optimization strategies, advantages, limitations and future directions, providing valuable guidance for researchers and practitioners navigating the dynamic landscape of modern drug delivery systems.

Coaxial Synthesis of PEI-Based Nanocarriers of Encapsulated RNA-Therapeutics to Specifically Target Muscle Cells

In this work, we performed a methodological comparative analysis to synthesize polyethyleneimine (PEI) nanoparticles using (i) conventional nanoprecipitation (NP), (ii) electrospraying (ES), and (iii) coaxial electrospraying (CA). The nanoparticles transported antisense oligonucleotides (ASOs), either encapsulated (CA nanocomplexes) or electrostatically bound externally (NP and ES nanocomplexes). After synthesis, the PEI/ASO nanoconjugates were functionalized with a muscle-specific RNA aptamer. Using this combinatorial formulation methodology, we obtained nanocomplexes that were further used as nanocarriers for the delivery of RNA therapeutics (ASO), specifically into muscle cells. In particular, we performed a detailed confocal microscopy-based comparative study to analyze the overall transfection efficiency, the cell-to-cell homogeneity, and the mean fluorescence intensity per cell of micron-sized domains enriched with the nanocomplexes. Furthermore, using high-magnification electron microscopy, we were able to describe, in detail, the ultrastructural basis of the cellular uptake and intracellular trafficking of nanocomplexes by the clathrin-independent endocytic pathway. Our results are a clear demonstration that coaxial electrospraying is a promising methodology for the synthesis of therapeutic nanoparticle-based carriers. Some of the principal features that the nanoparticles synthesized by coaxial electrospraying exhibit are efficient RNA-based drug encapsulation, increased nanoparticle surface availability for aptamer functionalization, a high transfection efficiency, and hyperactivation of the endocytosis and early/late endosome route as the main intracellular uptake mechanism.

Core-shell microparticles: From rational engineering to diverse applications

Core-shell microparticles, composed of solid, liquid, or gas bubbles surrounded by a protective shell, are gaining considerable attention as intelligent and versatile carriers that show great potential in biomedical fields. In this review, an overview is given of recent developments in design and applications of biodegradable core-shell systems. Several emerging methodologies including self-assembly, gas-shearing, and coaxial electrospray are discussed and microfluidics technology is emphasized in detail. Furthermore, the characteristics of core-shell microparticles in artificial cells, drug release and cell culture applications are discussed and the superiority of these advanced multi-core microparticles for the generation of artificial cells is highlighted. Finally, the respective developing orientations and limitations inherent to these systems are addressed. It is hoped that this review can inspire researchers to propel the development of this field with new ideas.

Development of novel gene carrier using modified nano hydroxyapatite derived from equine bone for osteogenic differentiation of dental pulp stem cells

Hydroxyapatite (HA) is a representative substance that induces bone regeneration. Our research team extracted nanohydroxyapatite (EH) from natural resources, especially equine bones, and developed it as a molecular biological tool. Polyethylenimine (PEI) was used to coat the EH to develop a gene carrier. To verify that PEI is well coated in the EH, we first observed the morphology and dispersity of PEI-coated EH (pEH) by electron microscopy. The pEH particles were well distributed, while only the EH particles were not distributed and aggregated. Then, the existence of nitrogen elements of PEI on the surface of the pEH was confirmed by EDS, calcium concentration measurement and fourier transform infrared spectroscopy (FT-IR). Additionally, the pEH was confirmed to have a more positive charge than the 25 kD PEI by comparing the zeta potentials. As a result of pGL3 transfection, pEH was better able to transport genes to cells than 25 kD PEI. After verification as a gene carrier for pEH, we induced osteogenic differentiation of DPSCs by loading the BMP-2 gene in pEH (BMP-2/pEH) and delivering it to the cells. As a result, it was confirmed that osteogenic differentiation was promoted by showing that the expression of osteopontin (OPN), osteocalcin (OCN), and runt-related transcription factor 2 (RUNX2) was significantly increased in the group treated with BMP-2/pEH. In conclusion, we have not only developed a novel nonviral gene carrier that is better performing and less toxic than 25 kD PEI by modifying natural HA (the agricultural byproduct) but also proved that bone differentiation can be effectively promoted by delivering BMP-2 with pEH to stem cells.

Electrospray: More than just an ionization source

Electrospraying (ES) is a potential-driven process of liquid atomization, which is employed in the field of analytical chemistry, particularly as an ionization technique for mass spectrometric analyses of biomolecules. In this review, we demonstrate the extraordinary versatility of the electrospray by overviewing the specifics and advanced applications of ES-based processing of low molecular mass compounds, biomolecules, polymers, nanoparticles, and cells. Thus, under suitable experimental conditions, ES can be used as a powerful tool for highly controlled deposition of homogeneous films or various patterns, which may sometimes even be organized into 3D structures. We also emphasize its capacity to produce composite materials including encapsulation systems and polymeric fibers. Further, we present several other, less common ES-based applications. This review provides an insight into the remarkable potential of ES, which can be very useful in the designing of innovative and unique strategies.

Electrospray for generation of drug delivery and vaccine particles applied in vitro and in vivo

Also known as electrospray, electrohydrodynamic atomization has been used extensively in the last 15 years to develop polymer-based particles for drug delivery in cell and animal models. More recently, novel core-shell, multi-axial, and other electrospray particles have been developed from an array of polymers for a variety of biomedical applications. This review focuses on electrospray as a novel method of particle fabrication for drug delivery, specifically highlighting the applications of these particle systems in cell culture and animal models while also discussing polymers used for particle fabrication. Applications of electrospray particles to treat glioma, ovarian cancer, and breast cancer are reviewed. Additionally, delivery of antibiotics, gene therapy, and bacterial cells formulated in electrospray particles is discussed. Finally, vaccines as well as drug eluting particles for differentiation of stem cells and tissue engineering are highlighted. The article concludes with a discussion of where the future of electrospray technology can go to strengthen its foothold in the biomedical field.

Numerical simulations of wall contact angle effects on droplet size during step emulsification

Terrace-based microfluidic devices are currently used to prepare highly monodisperse micro-droplets. Droplets are generated due to the spontaneous pressure drop induced by the Laplace pressure, and so the flow rate of a dispersed phase has little effect on droplet size. As a result, control over the droplet is limited once a step emulsification device has been fabricated. In this work, a terrace model was established to study the effect of the wall contact angle on droplet size based on computational fluid dynamics simulations. The results for contact angles from 140° to 180° show that a lower contact angle induces wall-wetting, increasing the droplet size. The Laplace pressure equations for droplet generation were determined based on combining pressure change curves with theoretical analyses, to provide a theoretical basis for controlling and handling droplets generated through step emulsification.

A study on the effects of wall contact angle makes it more flexible to predict and control the size of droplets generated in step emulsification.