Characterization of nanomedicines’ surface coverage using molecular probes and capillary electrophoresis

A comprehensive investigation of the interactions of human serum albumin with polymeric and hybrid nanoparticles

Nanoparticles (NPs) engineered as drug delivery systems continue to make breakthroughs as they offer numerous advantages over free therapeutics. However, the poor understanding of the interplay between the NPs and biomolecules, especially blood proteins, obstructs NP translation to clinics. Nano-bio interactions determine the NPs' in vivo fate, efficacy and immunotoxicity, potentially altering protein function. To fulfill the growing need to investigate nano-bio interactions, this study provides a systematic understanding of two key aspects: (i) protein corona (PC) formation and (ii) NP-induced modifications on protein's structure and stability. A methodology was developed by combining orthogonal techniques to analyze both quantitative and qualitative aspects of nano-bio interactions, using human serum albumin (HSA) as a model protein. Protein quantification via liquid chromatography-mass spectrometry, and capillary zone electrophoresis (CZE) clarified adsorbed protein quantity and stability. CZE further unveiled qualitative insights into HSA forms (native, glycated HSA and cysteinylated), while synchrotron radiation circular dichroism enabled analyzing HSA's secondary structure and thermal stability. Comparative investigations of NP cores (organic vs. hybrid), and shells (with or without polyethylene glycol (PEG)) revealed pivotal factors influencing nano-bio interactions. Polymeric NPs based on poly(lactic-co-glycolic acid) (PLGA) and hybrid NPs based on metal-organic frameworks (nanoMOFs) presented distinct HSA adsorption profiles. PLGA NPs had protein-repelling properties while inducing structural modifications on HSA. In contrast, HSA exhibited a high affinity for nanoMOFs forming a PC altering thereby the protein structure. A shielding effect was gained through PEGylation for both types of NPs, avoiding the PC formation as well as the alteration of unbound HSA structure.

Bioinspired zwitterionic triblock copolymers designed for colloidal drug delivery: 2 - Biological evaluation

In this work, poly(lactide) nanoparticles were equipped with a bioinspired coating layer based on poly[2-(methacryloyloxy)ethyl phosphorylcholine] and then evaluated when administered to the lungs and after intravenous injection. Compared to the plain counterparts, the chosen zwitterionic polymer shell prevented the coated colloidal formulation from aggregation and conditioned it for lower cytotoxicity, protein adsorption, complement activation and phagocytic cell uptake. Consequently, no interference with the biophysical function of the lung surfactant system could be detected accompanied by negligible protein and cell influx into the bronchoalveolar space after intratracheal administration. When injected into the central compartment, the coated formulation showed a prolonged circulation half-life and a delayed biodistribution to the liver. Taken together, colloidal drug delivery vehicles would clearly benefit from the investigated poly[2-(methacryloyloxy)ethyl phosphorylcholine]-based polymer coatings.

Shape stability of ellipsoidal nanomaterials prepared by physical deformation

The nonspherical shape of nanomaterials (NMs) represents a key attribute for controlling their biological behaviors. Analyzing shape stability over time represents a significant concern because nonspherical NMs are likely to rearrange into a thermodynamically more stable spherical shape. In this investigation, ellipsoidal NMs were designed by physical deformation of core/shell nanospheres composed of poly(isobutylcyanoacrylate) and chitosan or a mixture of chitosan and thiolated chitosan. After optimizing the process parameters for designing ellipsoidal NMs, the shape stability during storage was investigated for 6 months at different temperatures (4 °C, 20 °C and 40 °C). The NM shape was examined by analyzing the aspect ratio from images obtained by electron microscopy techniques. The results demonstrated the feasibility of designing shape-persistent ellipsoidal NMs by physical deformation of spherical particles.

Real-time visualization of morphology-dependent self-motion of hyaluronic acid nanomaterials in water

Drug delivery to target sites is often limited by inefficient particle transport through biological media. Herein, motion behaviors of spherical and nonspherical nanomaterials composed of hyaluronic acid were studied in water using real-time multiple particle tracking technology. The two types of nanomaterials have comparable surface compositions and surface potentials, and they have equivalent diameters. The analysis of nanomaterial trajectories revealed that particles with flattened morphology and a high aspect ratio, designated nanoplatelets, exhibited more linear trajectories and faster diffusion in water than nanospheres. Fitting the plots of mean square displacement vs. time scale suggests that nanoplatelets exhibited hyperdiffusive behavior, which is similar to the motion of living microorganisms. Furthermore, at 37 °C, the surface explored by a nanoplatelet was up to 33-fold higher than that explored by a nanosphere. This investigation on morphology-dependent self-motion of nanomaterials could have a significant impact on drug delivery applications by increasing particle transport through biological media.

A journey through the emergence of nanomedicines with poly(alkylcyanoacrylate) based nanoparticles

Starting in the late 1970s, the pioneering work of Patrick Couvreur gave birth to the first biodegradable nanoparticles composed of a biodegradable synthetic polymer. These nanoparticles, made of poly(alkylcyanoacrylate) (PACA), were the first synthetic polymer-based nanoparticulate drug carriers undergoing a phase III clinical trial so far. Analyzing the journey from the birth of PACA nanoparticles to their clinical evaluation, this paper highlights their remarkable adaptability to bypass various drug delivery challenges found on the way. At present, PACA nanoparticles include a wide range of nanoparticles that can associate drugs of different chemical nature and can be administered in vivo by different routes. The most recent technologies giving the nanoparticles customised functions could also be implemented on this family of nanoparticles. Through different examples, this paper discusses the seminal role of the PACA nanoparticles' family in the development of nanomedicines.