Rigor and reproducibility in polymer nanoparticle synthesis and characterization

Solid Lipid Nanoparticles Enhancing the Leishmanicidal Activity of Delamanid

Leishmaniasis, a zoonotic parasitic disease transmitted by infected sandflies, impacts nearly 1 million people yearly and is endemic in many countries across Asia, Africa, the Americas, and the Mediterranean; despite this, it remains a neglected disease with limited effective treatments, particularly in impoverished communities with limited access to healthcare. This study aims to repurpose approved drugs for an affordable leishmaniasis treatment. After the screening of potential drug candidates by reviewing databases and utilizing molecular docking analysis, delamanid was chosen to be incorporated into solid lipid nanoparticles (SLNPs). Both in cellulo and in vivo tests confirmed the successful payload release within macrophages and through the epidermis following topical application on murine skin. The evaluation of macrophages infected with L. infantum amastigotes showed that the encapsulated delamanid exhibited greater leishmanicidal activity compared with the free drug. The process of encapsulating delamanid in SLNPs, as demonstrated in this study, places a strong emphasis on employing minimal technology, ensuring energy efficiency, cost-effectiveness, and reproducibility. It enables consistent, low-cost production of nanomedicines, even on a small scale, offering a promising step toward more accessible and effective leishmaniasis treatments.

All-Aqueous, Surfactant-Free, and pH-Driven Nanoformulation Methods of Dual-Responsive Polymer Nanoparticles and their Potential use as Nanocarriers of pH-Sensitive Drugs

All-aqueous, surfactant-free, and pH-driven nanoformulation methods to generate pH- and temperature-responsive polymer nanoparticles (NPs) are described. Copolymers comprising a poly(methyl methacrylate) (PMMA) backbone with a few units of 2-(dimethylamino)ethyl methacrylate (DMAEMA) are solubilized in acidic buffer (pH 2.0) to produce pH-sensitive NPs. Copolymers of different molar mass (2.3-11.5 kg mol^-1 ) and DMAEMA composition (7.3-14.2 mol%) are evaluated using a "conventional" pH-driven nanoformulation method (i.e., adding an aqueous polymer solution (acidic buffer) into an aqueous non-solvent (basic buffer)) and a robotized method for pH adjustment of polymer dispersions. Dynamic light scattering, zeta-potential (ζ), and sedimentation-diffusion analyses suggest the formation of dual-responsive NPs of tunable size (from 20 to 110 nm) being stable for at least 28 days in the pH and temperature intervals from 2.0 to 6.0 and 25 to 50 °C, respectively. Ultraviolet-visible spectroscopic experiments show that these NPs can act as nanocarriers for the pH-sensitive dipyridamole drug, expanding its bioavailability and potential controlled release as a function of pH and temperature. These approaches offer alternative strategies to prepare stimuli-responsive NPs, avoiding the use of harmful solvents and complex purification steps, and improving the availability of biocompatible polymer nanoformulations for specific controlled release of pH-sensitive cargos.

Polymer nano-systems for the encapsulation and delivery of active biomacromolecular therapeutic agents

Biomacromolecular therapeutic agents, particularly proteins, antigens, enzymes, and nucleic acids are emerging as powerful candidates for the treatment of various diseases and the development of the recent vaccine based on mRNA highlights the enormous potential of this class of drugs for future medical applications. However, biomacromolecular therapeutic agents present an enormous delivery challenge compared to traditional small molecules due to both a high molecular weight and a sensitive structure. Hence, the translation of their inherent pharmaceutical capacity into functional therapies is often hindered by the limited performance of conventional delivery vehicles. Polymer drug delivery systems are a modular solution able to address those issues. In this review, we discuss recent developments in the design of polymer delivery systems specifically tailored to the delivery challenges of biomacromolecular therapeutic agents. In the future, only in combination with a multifaceted and highly tunable delivery system, biomacromolecular therapeutic agents will realize their promising potential for the treatment of diseases and for the future of human health.

Dual antibacterial drug-loaded nanoparticles synergistically improve treatment of Streptococcus mutans biofilms

Dental caries (i.e., tooth decay), which is caused by biofilm formation on tooth surfaces, is the most prevalent oral disease worldwide. Unfortunately, many anti-biofilm drugs lack efficacy within the oral cavity due to poor solubility, retention, and penetration into biofilms. While drug delivery systems (DDS) have been developed to overcome these hurdles and improve traditional antimicrobial treatments, including farnesol, efficacy is still modest due to myriad resistance mechanisms employed by biofilms, suggesting that synergistic drug treatments may be more efficacious. Streptococcus mutans (S. mutans), a cariogenic pathogen and biofilm forming model organism, has several key virulence factors including acidogenicity and exopolysaccharide (EPS) matrix synthesis. Flavonoids, such as myricetin, can reduce both biofilm acidogenicity and EPS synthesis. Therefore, a nanoparticle carrier (NPC) DDS with flexibility to co-load farnesol in the hydrophobic core and myricetin within the cationic corona, was tested in vitro using established and developing S. mutans biofilms. Co-loaded NPC treatments effectively disrupted biofilm biomass (i.e., dry weight) and reduced biofilm viability by ~3 log CFU/mL versus single drug-only controls in developing biofilms, suggesting dual-drug delivery exhibits synergistic anti-biofilm effects. Mechanistic studies revealed that co-loaded NPCs synergistically inhibited planktonic bacterial growth compared to controls and reduced S. mutans acidogenicity due to decreased atpD expression, a gene associated with acid tolerance. Moreover, the myricetin-loaded NPC corona enhanced NPC binding to tooth-mimetic surfaces, which can increase drug efficacy through improved retention at the biofilm-apatite interface. Altogether, these findings suggest promise for co-delivery of myricetin and farnesol DDS as an alternative anti-biofilm treatment to prevent dental caries.