Evaluation of mucoadhesive nanoparticle based nasal vaccine

Lipid-Polymer Hybrid Nanoparticles Synthesized via Lipid-Based Surface Engineering for a robust drug delivery platform

Herein, lipid-polymer core-shell hybrid nanoparticles composed of poly(D,L-lactic-co-glycolic acid) (PLGA)/lecithin (PLNs) were synthesized through lipid-based surface engineering. Lipids were absorbed onto the surface of the PLGA core to enhance the advantages of polymeric nanoparticles and liposomes. The amounts of lipids and encapsulation of the drug nicardipine hydrochloride (NCH) in the PLNs were studied. NCH-loaded PLNs (NCH-PLNs) were produced in high yield (66%) with a high encapsulation efficiency (92%) and a size of 176 nm. The mass of phosphorus (P) on the NCH-PLN surface was qualitatively and quantitatively investigated using X-ray fluorescence spectroscopy, and lecithin addition increased the P mass percentage due to the phosphate group (PO43-) in its structure. These data confirmed the lipid-based surface engineering of NCH-PLNs. The zeta potential of NCH-PLN exceeded -30 mV, ensuring colloidal stability, and preventing precipitation through electrostatic stabilization. In vitro, NCH was continuously and slowly released from NCH-PLNs over 16 days. Furthermore, PSVK1 cells exhibited high viability after treatment with NCH-PLNs, indicating favorable cytocompatibility. After comparing various mathematical equations of drug release kinetics, the data best fit the Korsmeyer-Peppas model with R2 values of 0.989, 0.990, and 0.982 for 1.0, 3.0, and 5.0 mg/mL lecithin, respectively. The release exponents obtained ranged from 0.480 to 0.505, suggesting anomalous transport release. Thus, NCH-PLNs have potential as a robust drug delivery platform for the controlled administration of NCH, particularly for vasodilation during neurosurgery.

The Role of Mucoadhesion and Mucopenetration in the Immune Response Induced by Polymer-Based Mucosal Adjuvants

Mucus is a viscoelastic gel that acts as a protective barrier for epithelial surfaces. The mucosal vehicles and adjuvants need to pass through the mucus layer to make drugs and vaccine delivery by mucosal routes possible. The mucoadhesion of polymer particle adjuvants significantly increases the contact time between vaccine formulations and the mucosa; then, the particles can penetrate the mucus layer and epithelium to reach mucosa-associated lymphoid tissues. This review presents the key findings that have aided in understanding mucoadhesion and mucopenetration while exploring the influence of physicochemical characteristics on mucus-polymer interactions. We describe polymer-based particles designed with mucoadhesive or mucopenetrating properties and discuss the impact of mucoadhesive polymers on local and systemic immune responses after mucosal immunization. In future research, more attention paid to the design and development of mucosal adjuvants could lead to more effective vaccines.

Combating Intracellular Pathogens with Nanohybrid-Facilitated Antibiotic Delivery

BACKGROUND

Lipid polymer hybrid nanoparticles (LPHNPs) have been widely investigated in drug and gene delivery as well as in medical imaging. A knowledge of lipid-based surface engineering and its effects on how the physicochemical properties of LPHNPs affect the cell-nanoparticle interactions, and consequently how it influences the cytological response, is in high demand.

METHODS

Herein, we have engineered antibiotic-loaded (doxycycline or vancomycin) LPHNPs with cationic and zwitterionic lipids and examined the effects on their physicochemical characteristics (size and charge), antibiotic entrapment efficiency, and the in vitro intracellular bacterial killing efficiency against Mycobacterium smegmatis or Staphylococcus aureus infected macrophages.

RESULTS

The incorporation of cationic or zwitterionic lipids in the LPHNP formulation resulted in a size reduction in LPHNPs formulations and shifted the surface charge of bare NPs towards positive or neutral values. Also observed were influences on the drug incorporation efficiency and modulation of the drug release from the biodegradable polymeric core. The therapeutic efficacy of LPHNPs loaded with vancomycin was improved as its minimum inhibitory concentration (MIC) (2 µg/mL) versus free vancomycin (4 µg/mL). Importantly, our results show a direct relationship between the cationic surface nature of LPHNPs and its intracellular bacterial killing efficiency as the cationic doxycycline or vancomycin loaded LPHNPs reduced 4 or 3 log CFU respectively versus the untreated controls.

CONCLUSION

In our study, modulation of surface charge in the nanomaterial formulation increased macrophage uptake and intracellular bacterial killing efficiency of LPHNPs loaded with antibiotics, suggesting alternate way for optimizing their use in biomedical applications.

Biodegradable polymers for modern vaccine development

Most traditional vaccines are composed either of a whole pathogen or its parts; these vaccines, however, are not always effective and can even be harmful. As such, additional agents known as adjuvants are necessary to increase vaccine safety and efficacy. This review summarizes the potential of biodegradable materials, including synthetic and natural polymers, for vaccine delivery. These materials are highly biocompatible and have minimal toxicity, and most biomaterial-based vaccines delivering antigens or adjuvants have been shown to improve immune response, compared to formulations consisting of the antigen alone. Therefore, these materials can be applied in modern vaccine development.

Nasal vaccination with poly(β-amino ester)-poly(d,l-lactide-co-glycolide) hybrid nanoparticles

Mucosal vaccination stimulates both mucosal and systemic immunity. However, mucosal applications of vaccine antigens in their free form generally result in poor systemic immune responses and need adjuvantation. In this study, bovine serum albumin loaded, new hybridised poly(β-amino ester)-poly(d,l-lactide-co-glycolide) nanoparticles were prepared by double emulsion-solvent evaporation method, characterised and evaluated in vivo as nasal vaccine carriers. Cationic spherical particles with a mean size of 240nm, good physical stability and high encapsulation efficiency were obtained. Protein structure was not affected throughout preparation and minimal toxicity was shown in Calu-3 and A549 cells. Nasal vaccination with these nanoparticles revealed markedly higher humoral immune responses compared with free antigen following intranasal and subcutaneous immunisation. Mucosal immune response was also stimulated and cytokine titres indicated that Th1 and Th2 pathways were successfully activated. This study shows that the formulated hybrid nanoparticles can be a promising carrier for nasal immunisation of poor antigenic proteins.

Nasal Vaccine Delivery

The mucosal surfaces represent the major site of entry of many pathogens, and major challenges in vaccine development include safety and stability in a suitable dosage form. Micro- and nanocarrier-based delivery systems as nasal vaccines induce humoral, cellular, and mucosal immunity. The nasal route of vaccination could also offer immunity at several distant mucosal sites (oral, rectal, vaginal, and pulmonary), which is considered a simplified and cost-effective mode of vaccination with enhanced patient compliance. Most of the nasal vaccine delivery systems in the form of microparticulates, nanoparticulates, and liposomes are currently under development and prove to offer immunity in animal models. The importance and potential of the nasal route of administration for vaccines is unexplored, and this chapter outlines the opportunities, challenges, and potential delivery solutions to facilitate the development of improved nasal vaccines for infectious diseases.

Lipid-based surface engineering of PLGA nanoparticles for drug and gene delivery applications

The use of poly(lactic-co-glycolic acid) (PLGA)-based nanocarriers presents several major challenges, including their synthetic hydrophobic surface, low transfection efficiency, short circulation half-life, and nonspecific tissue distribution. Numerous engineering strategies have been employed to overcome these problems, with lipid-based surface functionalization of PLGA nanoparticles (NPs) showing promising results in the development of PLGA-based clinical nanomedicines. Surface engineering with different lipids enhances the target specificity of the carrier and improves its physicochemical properties as well as NP-cell associations, such as cellular membrane permeability, immune responses, and long circulation half-life in vivo. This review focuses on recent advances in the lipid-based surface engineering of PLGA NPs for drug and gene delivery applications.