Cationic liposomes produced via ethanol injection method for dendritic cell therapy

Anti-Obesity Drug Delivery Systems: Recent Progress and Challenges

Obesity has reached an epidemic proportion in the last thirty years, and it is recognized as a major health issue in modern society now with the possibility of serious social and economic consequences. By the year 2030, nearly 60% of the global population may be obese or overweight, which emphasizes a need for novel obesity treatments. Various traditional approaches, such as pharmacotherapy and bariatric surgery, have been utilized in clinical settings to treat obesity. However, these methods frequently show the possibility of side effects while remaining ineffective. There is, therefore, an urgent need for alternative obesity treatments with improved efficacy and specificity. Polymeric materials and chemical strategies are employed in emerging drug delivery systems (DDSs) to enhance therapy effectiveness and specificity by stabilizing and controlling the release of active molecules such as natural ingredients. Designing DDSs is currently a top priority research objective with an eye towards creating obesity treatment approaches. In reality, the most recent trends in the literature demonstrate that there are not enough in-depth reviews that emphasize the current knowledge based on the creation and design of DDSs for obesity treatment. It is also observed in the existing literature that a complex interplay of different physical and chemical parameters must be considered carefully to determine the effectiveness of the DDSs, including microneedles, for obesity treatment. Additionally, it is observed that these properties depend on how the DDS is synthesized. Although many studies are at the animal-study stage, the use of more advanced DDS techniques would significantly enhance the development of safe and efficient treatment approaches for obese people in the future. Considering these, this review provides an overview of the current anti-obesity treatment approaches as well as the conventional anti-obesity therapeutics. The article aims to conduct an in-depth discussion on the current trends in obesity treatment approaches. Filling in this knowledge gap will lead to a greater understanding of the safest ways to manage obesity.

The role of dendritic cells in the immunomodulation to implanted biomaterials

Considering the substantial role played by dendritic cells (DCs) in the immune system to bridge innate and adaptive immunity, studies on DC-mediated immunity toward biomaterials principally center on their adjuvant effects in facilitating the adaptive immunity of codelivered antigens. However, the effect of the intrinsic properties of biomaterials on dendritic cells has not been clarified. Recently, researchers have begun to investigate and found that biomaterials that are nonadjuvant could also regulate the immune function of DCs and thus affect subsequent tissue regeneration. In the case of proteins adsorbed onto biomaterial surfaces, their intrinsic properties can direct their orientation and conformation, forming “biomaterial-associated molecular patterns (BAMPs)”. Thus, in this review, we focused on the intrinsic physiochemical properties of biomaterials in the absence of antigens that affect DC immune function and summarized the underlying signaling pathways. Moreover, we preliminarily clarified the specific composition of BAMPs and the interplay between some key molecules and DCs, such as heat shock proteins (HSPs) and high mobility group box 1 (HMGB1). This review provides a new direction for future biomaterial design, through which modulation of host immune responses is applicable to tissue engineering and immunotherapy.

Enhanced anti-breast cancer efficacy of co-delivery liposomes of docetaxel and curcumin

The successful treatment of breast cancer is hampered by toxicity to normal cells, impaired drug accumulation at the tumor site, and multidrug resistance. We designed a novel multifunctional liposome, CUR-DTX-L, to co-deliver curcumin (CUR) and the chemotherapeutic drug docetaxel (DTX) for the treatment of breast cancer in order to address multidrug resistance (MDR) and the low efficacy of chemotherapy. The mean particle size, polydispersity index, zeta potential, and encapsulation efficiency of CUR-DTX-L were 208.53 ± 6.82 nm, 0.055 ± 0.001, -23.1 ± 2.1 mV, and 98.32 ± 2.37%, respectively. An in vitro release study and CCK-8 assays showed that CUR-DTX-L has better sustained release effects and antitumor efficacy than free drugs, the antitumor efficacy was verified by MCF-7 tumor-bearing mice, the CUR-DTX-L showed better antitumor efficacy than other groups, and the in vivo pharmacokinetic study indicated that the plasma concentration-time curve, mean residence time, and biological half-life time of CUR-DTX-L were significantly increased compared with free drugs, suggesting that it is a promising drug delivery system for the synergistic treatment of breast cancer.

The diffusion-driven microfluidic process to manufacture lipid-based nanotherapeutics with stealth properties for siRNA delivery

Our study investigated the manufacturing of lipid-based nanotherapeutics with stealth properties for siRNA delivery by employing a diffusion-driven microfluidic process in one or two-steps strategies to produce siRNA-loaded lipid nanocarriers and lipoplexes, respectively. In the one-step synthesis, siRNA in the aqueous phase is introduced from one inlet, while phospholipids dispersed in anhydrous ethanol are introduced from other inlets, generating the lipid nanocarriers. In the two-steps strategies, the pre-formed liposomes are complexed with siRNA. The process configuration with an aqueous diffusion barrier exerts a significant effect on the nanoaggregates synthesis. Dynamic light scattering data showed that lipid nanocarriers had a bigger particle diameter (298 ± 24 nm) and surface charge (43 ± 6 mV) compared to lipoplexes (194 ± 7 nm and 37.0 ± 0.4 mV). Moreover, DSPE-PEG(2000) was included in the formulation to synthesize lipid-based nanotherapeutics containing siRNA with stealth characteristics. The inclusion of PEG-lipid resulted in an increase in the surface charge of lipoplexes (from 33.7 ± 4.4-54.3 ± 1.6 mV), while a significant decrease was observed in the surface charge of lipid nanocarriers (30.3 ± 8.7 mV). The different structural assemblies were identified for lipoplex and lipid nanocarriers using Synchrotron SAXS. Lipid nanocarriers present a lower amount of multilayers than lipoplexes. Lipid-PEG insertion significantly influenced lipid nanocarriers' characteristics, drastically decreasing the number of multilayers. This effect was not observed in lipoplexes. The association between process configuration, lipid composition, and its effect on the characteristics of lipid-based vector systems can generate fundamental insights, contributing to gene-based nanotherapeutics development.

Hybrid polymer/lipid vesicle synthesis: Association between cationic liposomes and lipoplexes with chondroitin sulfate

The association of cationic carriers with different anionic mucoadhesive biopolymers has been widely explored as an alternative to improve their delivery routes and specific targeting. This work presents a complete analysis of the association between chondroitin sulfate (CS) and cationic liposomes (CLs)/lipoplex (CL-pDNA). In this study, plasmid DNA (pDNA) was used as a genetic cargo for association with carriers. Firstly, we measured the stoichiometry of pseudo complexes and evaluated their colloidal properties, structural and morphological characteristics. Optimized CL-pDNA lipoplexes (positive z-potential) and CL-CS / CL-pDNA-CS (negative z-potential with CS mass ratio of 9% (w/w)) were further studied in detail. Small-angle X-ray scattering analysis and cryo-transmission electron microscopy micrographs revealed that the electrostatic interaction between CS and CL / CL-pDNA easily reorganized the lipid bilayers resulting in nanoscale uni/multilamellar vesicles. A high CS mass ratio (9% (w/w)) led to the reassembly of liposomal structure, wherein the pDNA was easily exchanged for CS chains, forming more than 50% of dense multilamellar vesicles. This data evidenced that the association between CS and CLs is not a conventional coating process since it generates complex and hybrid structures. We believe that these obtained colloidal data may be used in the future to investigate polymer-tailored nanocarriers and their production process. In brief, the colloidal study of hybrid structures may open interesting perspectives for developing novel carriers for drug and gene delivery applications.

Recent advances in co-delivery nanosystems for synergistic action in cancer treatment

Nanocarrier delivery systems have been widely studied to carry unique or dual chemical drugs. The major challenge of chemotherapies is to overcome the multidrug-resistance (MDR) of cells to antineoplastic medicines. In this context, nano-scale technology has allowed researchers to develop biocompatible nano-delivery systems to overcome the limitation of chemical agents. The development of nano-vehicles may also be directed to co-deliver different agents such as drugs and genetic materials. The delivery of nucleic acids targeting specific cells is based on gene therapy principles to replace the defective gene, correct genome errors or knock-down a particular gene. Co-delivery systems are attractive strategies due to the possibility of achieving synergistic therapeutic effects, which are more effective in overcoming the MDR of cancer cells. These combined therapies can provide better outcomes than separate delivery approaches carrying either siRNA, miRNA, pDNA, or drugs. This article reviews the main design features that need to be associated with nano-vehicles to co-deliver drugs, genes, and gene-drug combinations with efficacy. The advantages and disadvantages of co-administration approaches are also overviewed and compared with individual nanocarrier systems. Herein, future trends and perspectives in designing novel nano-scale platforms to co-deliver therapeutic agents are also discussed.

Artificial neural networks in tandem with molecular descriptors as predictive tools for continuous liposome manufacturing

The current study utilized an artificial neural network (ANN) to generate computational models to achieve process optimization for a previously developed continuous liposome manufacturing system. The liposome formation was based on a continuous manufacturing system with a co-axial turbulent jet in a co-flow technology. The ethanol phase with lipids and aqueous phase resulted in liposomes of homogeneous sizes. The input features of the ANN included critical material attributes (CMAs) (e.g., hydrocarbon tail length, cholesterol percent, and buffer type) and critical process parameters (CPPs) (e.g., solvent temperature and flow rate), while the ANN outputs included critical quality attributes (CQAs) of liposomes (i.e., particle size and polydispersity index (PDI)). Two common ANN architectures, multiple-input-multiple-output (MIMO) models and multiple-input-single-output (MISO) models, were evaluated in this study, where the MISO outperformed MIMO with improved accuracy. Molecular descriptors, obtained from PaDEL-Descriptor software, were used to capture the physicochemical properties of the lipids and used in training of the ANN. The combination of CMAs, CPPs, and molecular descriptors as inputs to the MISO ANN model reduced the training and testing mean relative error. Additionally, a graphic user interface (GUI) was successfully developed to assist the end-user in performing interactive simulated risk analysis and visualizing model predictions.

Emerging advances in cationic liposomal cancer nanovaccines: opportunities and challenges

Advancements in the field of cancer therapeutics have witnessed a recent surge in the use of liposomes. The physicochemical characteristics of the liposomes and their components, including the lipid phase transition temperature, vesicular size and size distribution, surface properties, and route of administration, play a significant role in the modulation of the immune response as an adjuvant and for loaded antigen (Ag). Cationic liposomes, concerning their potential ability to amplify the immunogenicity of the loaded Ag/adjuvant, have received enormous interest as a promising vaccine delivery platform for cancer immunotherapy. In the present review, the physicochemical considerations for the development of Ag/adjuvant-loaded liposomes and the cationic liposomes' effectiveness for promoting cancer immunotherapy have been summarized.

Bulk and Microfluidic Synthesis of Stealth and Cationic Liposomes for Gene Delivery Applications

This chapter describes the synthesis of stealth and cationic liposomes and their complexation with plasmid DNA to generate lipoplexes for gene delivery applications. Two techniques are presented: a top-down approach which requires a second step of processing for downsizing the liposomes (i.e., ethanol injection method) and a microfluidic technique that explores the diffusion of ethanol in water to allow the proper lipid self-assembly. The synthesis of stealth liposomes is also a challenge since the use of poly(ethylene glycol) favors the formation of oblate micelles. In this protocol, the stealth cationic liposome synthesis by exploring the high ionic strength to overcome the formation of secondary structures like micelles is described. Finally, the electrostatic complexation between cationic liposomes and DNA is described, indicating important aspects that guarantee the formation of uniform lipoplexes.