Hydrodynamic electrospray ionization jetting of calcium alginate particles: effect of spray-mode, spraying distance and concentration

Cellulose nanocrystal-based hydrogel microspheres prepared via electrohydrodynamic processes for controlled release of bioactive compounds

Controlled release systems (CRSs) have been sought after as a compelling platform for site-specific delivery of bioactive compounds (BCs), including traditional drugs and food supplements. However, their potential is often hindered by challenges such as non-uniformity and structural instability. This study utilized an electrohydrodynamic (EHD) process to synthesize composites of cellulose nanocrystals (CNCs) (in two forms: colloidal (c) and crosslinked (x)) and alginate (ALG) to produce uniformly shaped hydrogel microspheres (HMs), serving as pH-sensitive CRSs for BC encapsulation. Hydrophobic and hydrophilic dyes, as model BCs, were loaded in HMs. Bead shapes were assessed by sphericity factors (values ≤0.05). Size depended on applied voltage, as it ranged from ∼1200 μm (voltage-OFF) to 300 μm (voltage-ON). Release mechanism of dye-loaded HMs was studied at pH 2.4 and pH 8.2 (to mimic acidic conditions in stomach and basic conditions in small intestine) using Korsmeyer-Peppas model. Release exponents (n) of dyes for different compositions indicated pH-dependent delivery through non-Fickian diffusion (0.43 ≤ n ≤ 0.85) and case-II transport (n ≥ 0.85) mechanisms. BC-loaded cCNC-ALG and xCNC-ALG composites, prepared via EHDs, demonstrated potential for designing efficient pH-sensitive CRSs for applications in various industries, ranging from nutraceutical and pharmaceutical to food and agriculture.

Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties

This study reports on the two-step manufacturing process of a filtration media obtained by first electrospinning a layer of polycaprolactone (PCL) non-woven fibers onto a paper filter backing and subsequently coating it by electrospraying with a second layer made of pure acidolysis lignin. The manufacturing of pure lignin coatings by solution electrospraying represents a novel development that requires fine control of the underlying electrodynamic processing. The effect of increasing deposition time on the lignin coating was investigated for electrospray time from 2.5 min to 120 min. Microstructural and physical characterization included SEM, surface roughness analysis, porosity tests, permeability tests by a Gurley densometer, ATR-FTIR analysis, and contact angle measurements vs. both water and oil. The results indicate that, from a functional viewpoint, such a natural coating endowed the membrane with an amphiphilic behavior that enabled modulating the nature of the bare PCL non-woven substrate. Accordingly, the intrinsic hydrophobic behavior of bare PCL electrospun fibers could be reduced, with a marked decrease already for a thin coating of less than 50 nm. Instead, the wettability of PCL vs. apolar liquids was altered in a less predictable manner, i.e., producing an initial increase of the oil contact angles (OCA) for thin lignin coating, followed by a steady decrease in OCA for higher densities of deposited lignin. To highlight the effect of the lignin type on the results, two grades of oak (AL-OA) of the Quercus cerris L. species and eucalyptus (AL-EU) of the Eucalyptus camaldulensis Dehnh species were compared throughout the investigation. All grades of lignin yielded coatings with measurable antibacterial properties, which were investigated against Staphylococcus aureus and Escherichia coli, yielding superior results for AL-EU. Remarkably, the lignin coatings did not change overall porosity but smoothed the surface roughness and allowed modulating air permeability, which is relevant for filtration applications. The findings are relevant for applications of this abundant biopolymer not only for filtration but also in biotechnology, health, packaging, and circular economy applications in general, where the reuse of such natural byproducts also brings a fundamental demanufacturing advantage.

Designing Advanced Drug Delivery Systems: Core-Shell Alginate Particles through Electro-Fluid Dynamic Atomization

Innovations in drug delivery systems are crucial for enhancing therapeutic efficiency. Our research presents a novel approach based on using electro-fluid dynamic atomization (EFDA) to fabricate core-shell monophasic particles (CSMp) from sodium alginate blends of varying molecular weights. This study explores the morphological characteristics of these particles in relation to material properties and process conditions, highlighting their potential in drug delivery applications. A key aspect of our work is the development of a mathematical model that simulates the release kinetics of small molecules, specifically sodium diclofenac. By assessing the diffusion properties of different molecules and gel formulations through transport and rheological models, we have created a predictive tool for evaluating the efficiency of these particles in drug delivery. Our findings underscore two critical, independent parameters for optimizing drug release: the external shell thickness and the diffusivity ratios within the dual layers. This allows for precise control over the timing and intensity of the release profile. This study advances our understanding of EFDA in the fabrication of CSMp and offers promising avenues for enhancing drug delivery systems by tailoring release profiles through particle characteristic manipulation.

Detection of Micrometer-Sized Virus Aerosols by Using a Real-Time Bioaerosol Monitoring System

This study investigates a real-time handheld bioaerosol monitoring system for the detection of biological particles using UV-LED and light-induced fluorescence technology. Biological particles produce both scattering and fluorescence signals simultaneously, which can help distinguish them from general particles. The detected scattering, fluorescence, and simultaneous signals are then converted into photon signals and categorized based on predetermined criteria. A reliable biological particle generator was required to validate the performance of the system. This study explores the use of an M13 bacteriophage as a virus simulant of biological agents and employs a customized inkjet aerosol generator to produce M13 bacteriophage aerosols of a specific size by controlling the concentration of M13. We confirmed that micro-sized, narrowly dispersed M13 aerosols were efficiently generated. Additionally, we confirmed the performance of this real-time handheld bioaerosol monitoring system by detecting viruses.

Electrosprayed Particles Loaded with Kartogenin as a Potential Osteochondral Repair Implant

The restoration of cartilage damage is a slow and not always successful process. Kartogenin (KGN) has significant potential in this space-it is able to induce the chondrogenic differentiation of stem cells and protect articular chondrocytes. In this work, a series of poly(lactic-co-glycolic acid) (PLGA)-based particles loaded with KGN were successfully electrosprayed. In this family of materials, PLGA was blended with a hydrophilic polymer (either polyethyleneglycol (PEG) or polyvinylpyrrolidone (PVP)) to control the release rate. Spherical particles with sizes in the range of 2.4-4.1 µm were fabricated. They were found to comprise amorphous solid dispersions, with high entrapment efficiencies of >93%. The various blends of polymers had a range of release profiles. The PLGA-KGN particles displayed the slowest release rate, and blending with PVP or PEG led to faster release profiles, with most systems giving a high burst release in the first 24 h. The range of release profiles observed offers the potential to provide a precisely tailored profile via preparing physical mixtures of the materials. The formulations are highly cytocompatible with primary human osteoblasts.

Conductive and Adhesive Granular Alginate Hydrogels for On-Tissue Writable Bioelectronics

Conductive hydrogels are promising materials in bioelectronics that ensure a tissue-like soft modulus and re-enact the electrophysiological function of damaged tissues. However, recent approaches to fabricating conductive hydrogels have proved difficult: fixing of the conductive hydrogels on the target tissues hydrogels requires the aids from other medical glues because of their weak tissue-adhesiveness. In this study, an intrinsically conductive and tissue-adhesive granular hydrogel consisting of a PEDOT:PSS conducting polymer and an adhesive catechol-conjugated alginate polymer was fabricated via an electrohydrodynamic spraying method. Because alginate-based polymers can be crosslinked by calcium ions, alginate-catechol polymers mixed with PEDOT:PSS granular hydrogels (ACP) were easily fabricated. The fabricated ACP exhibited not only adhesive and shear-thinning properties but also conductivity similar to that of muscle tissue. Additionally, the granular structure makes the hydrogel injectable through a syringe, enabling on-tissue printing. This multifunctional granular hydrogel can be applied to soft and flexible electronics to connect humans and machines.

Alginate-Based Smart Materials and Their Application: Recent Advances and Perspectives

Nature produces materials using available molecular building blocks following a bottom-up approach. These materials are formed with great precision and flexibility in a controlled manner. This approach offers the inspiration for manufacturing new artificial materials and devices. Synthetic artificial materials can find many important applications ranging from personalized therapeutics to solutions for environmental problems. Among these materials, responsive synthetic materials are capable of changing their structure and/or properties in response to external stimuli, and hence are termed "smart" materials. Herein, this review focuses on alginate-based smart materials and their stimuli-responsive preparation, fragmentation, and applications in diverse fields from drug delivery and tissue engineering to water purification and environmental remediation. In the first part of this report, we review stimuli-induced preparation of alginate-based materials. Stimuli-triggered decomposition of alginate materials in a controlled fashion is documented in the second part, followed by the application of smart alginate materials in diverse fields. Because of their biocompatibility, easy accessibility, and simple techniques of material formation, alginates can provide solutions for several present and future problems of humankind. However, new research is needed for novel alginate-based materials with new functionalities and well-defined properties for targeted applications.

Alginate Nanoformulation: Influence of Process and Selected Variables

Nanocarriers are defined as structures and devices that are constructed using nanomaterials which add functionality to the encapsulants. Being small in size and having a customized surface, improved solubility and multi-functionality, it is envisaged that nanoparticles will continue to create new biomedical applications owing to their stability, solubility, and bioavailability, as well as controlled release of drugs. The type and physiochemical as well as morphological attributes of nanoparticles influence their interaction with living cells and determine the route of administration, clearance, as well as related toxic effects. Over the past decades, biodegradable polymers such as polysaccharides have drowned a great deal of attention in pharmaceutical industry with respect to designing of drug delivery systems. On this note, biodegradable polymeric nanocarrier is deemed to control the release of the drug, stabilize labile molecules from degradation and site-specific drug targeting, with the main aim of reducing the dosing frequency and prolonging the therapeutic outcomes. Thus, it is essential to select the appropriate biopolymer material, e.g., sodium alginate to formulate nanoparticles for controlled drug delivery. Alginate has attracted considerable interest in pharmaceutical and biomedical applications as a matrix material of nanocarriers due to its inherent biological properties, including good biocompatibility and biodegradability. Various techniques have been adopted to synthesize alginate nanoparticles in order to introduce more rational, coherent, efficient and cost-effective properties. This review highlights the most used and recent manufacturing techniques of alginate-based nanoparticulate delivery system, including emulsification/gelation complexation, layer-by-layer, spray drying, electrospray and electrospinning methods. Besides, the effects of the main processing and formulation parameters on alginate nanoparticles are also summarized.

Magnetically-guided hydrogel capsule motors produced via ultrasound assisted hydrodynamic electrospray ionization jetting

Hydrogel capsules are a potential candidate for drug delivery and an interesting alternative to polyelectrolyte multilayer capsules which are under investigation since 20 years. Recently introduced polyelectrolyte complex capsules produced by spraying are non-biodegradable and not biocompatible, which limits their practical application, while biodegradable alginate capsules require complex coaxial electrospray ionization jetting. In this work, biodegradable alginate capsules cross-linked by calcium are successfully produced by hydrodynamic electrospray ionization jetting with the assistance of low frequency ultrasound. The size and shape of most capsules show significant differences with respect to different spraying distance, spraying mode, electrode shape and spraying concentration. Capsules in the shape of vase, mushrooms and spheres were successfully produced. Average capsule size can be adjusted from 10 μm to 2 mm. These capsules are used to encapsulate a model drug. Encapsulated paramagnetic particles enable defined directional motion under the propulsion of a rotating magnetic field, while model drugs can be released by ultrasound.

Biodistribution, Safety and Organ Toxicity of Docetaxel-Loaded in HER-2 Aptamer Conjugated Ecoflex® Nanoparticles in a Mouse Xenograft Model of Ovarian Cancer

BACKGROUND

Docetaxel is a notably efficient anticancer drug administered for several types of malignancies including ovarian cancer. However, various side effects caused either by the nonspecific distribution of the active ingredient or by high contents of Tween 80 and ethanol in the currently marketed formulations, could even deprive the patients of the treatment.

OBJECTIVES

In the current study, a novel targeted delivery system composed of Ecoflex® polymeric nanoparticles loaded with docetaxel and equipped with HER-2 specific aptamer molecules was evaluated regarding blood and tissue toxicity, and biodistribution.

METHOD

The tumor-bearing nude mice, achieved by subcutaneous injection of SKOV-3 cells, were divided into four groups treated with normal saline, Taxotere®, targeted docetaxel nanoparticles, and non-targeted docetaxel nanoparticles. Few patents were alos cied in the article.

RESULTS

According to the results of hematologic evaluations, almost all hematologic parameters were in normal range with no significant difference among the four groups. Histopathological studies revealed that treatment with targeted nanoparticles caused a remarkable reduction in mitosis in tumor sections and overall reduced organ toxicity compared with Taxotere®. The only exception was spleen in which more damage was caused by the nanoparticles. The results of the biodistribution study were also in accordance with pathological assessments, with significantly lower drug concentration in non-tumor tissues, except for spleen, when targeted nanoparticles were used compared with Taxotere®.

CONCLUSION

These results could evidence the efficiency of the targeted delivery system in concentrating the drug cargo mostly in its site of action leading to the elimination of its adverse effects caused by exposure of other tissues to the cytotoxic agent.