Understanding Nanomedicine Size and Biological Response Dependency: What Is the Relevance of Previous Relationships Established on Only Batch-Mode DLS-Measured Sizes?

PURPOSE: Most relationships between size and nanomedicine performance and safety were established before the early 2010s' when batch-mode dynamic light scattering (batch-mode DLS) was the only easy size measurement method for colloids available. They are basis for the rational design of nanomedicines, but misunderstood contrasting results are reported. This work aimed to investigate whether these relationships can be used with confidence knowing that batch-mode DLS can be tricky when measuring sizes of polydisperse systems. METHODS: A polydisperse dispersion of polymer nanoparticles ranging from 100 to 465 nm was synthesized. The particles were separated in 4 fractions by successive centrifugations. The capacity of each fraction and parent dispersion to activate the complement system was evaluated by Crossed immuno-electrophoresis. RESULTS: Each fraction was a population of particles with a distinct size. It showed a different capacity to activate the complement system. Particles of the fractions showing the strongest capacity to activate the complement systems had a different size evaluated by batch-mode DLS then that of the parent particles. CONCLUSION: Particles activating the complement system in the parent dispersion were not those that were detected by batch-mode DLS while measuring its size. This work pointed out that previously established relationships between nanomedicine size and their biological response should be taken with caution if sizes were only measured by batch-mode DLS.

Xylan in drug delivery: A review of its engineered structures and biomedical applications.

Xylan, an abundant biopolymer mainly extracted from plants and algae, is commonly studied for textile, food and biomedical applications. In this review, different approaches to obtain xylan-based products for drug delivery purposes were described. Investigations about xylan-based films, micro- and nanostructure, with the ability or not to swell (hydrogels), developed for biomedical applications, were summarized. Furthermore, a section on colon drug delivery and the methods that have been developed for the evaluation of these systems were presented.

Tuning complement activation and pathway through controlled molecular architecture of dextran chains in nanoparticle corona.

The understanding of complement activation by nanomaterials is a key to a rational design of safe and efficient nanomedicines. This work proposed a systematic study investigating how molecular design of nanoparticle coronas made of dextran impacts on mechanisms that trigger complement activation. The nanoparticles used for this work consisted of dextran-coated poly(isobutylcyanoacrylate) (PIBCA) nanoparticles have already been thoroughly characterized. Their different capacity to trigger complement activation established on the cleavage of the protein C3 was also already described making these nanoparticles good models to investigate the relation between the molecular feature of their corona and the mechanism by which they triggered complement activation. Results of this new study show that complement activation pathways can be selected by distinct architectures formed by dextran chains composing the nanoparticle corona. Assumptions that explain the relation between complement activation mechanisms triggered by the nanoparticles and the nanoparticle corona molecular feature were proposed. These results are of interest to better understand how the design of dextran-coated nanomaterials will impact interactions with the complement system. It can open perspectives with regard to the selection of a preferential complement activation pathway or prevent the nanoparticles to activate the complement system, based on a rational choice of the corona configuration.