Small angle X-ray scattering (SAXS),
electrospray ionization charge
detection mass spectrometry (CD-MS), dynamic light scattering (DLS),
and transmission electron microscopy (TEM) are used to characterize
poly(glycerol monomethacrylate)55-poly(2-hydroxypropyl
methacrylate)x (G55-Hx) vesicles prepared by polymerization-induced self-assembly
(PISA) using a reversible addition–fragmentation chain transfer
(RAFT) aqueous dispersion polymerization formulation. A G55 chain transfer agent is utilized to prepare a series of G55-Hx diblock copolymers, where the mean
degree of polymerization (DP) of the membrane-forming block (x) is varied from 200 to 2000. TEM confirms that vesicles
with progressively thicker membranes are produced for x = 200–1000, while SAXS indicates a gradual reduction in mean
aggregation number for higher x values, which is
consistent with CD-MS studies. Both DLS and SAXS studies indicate
minimal change in the overall vesicle diameter between x = 400 and 800. Fitting SAXS patterns to a vesicle model enables
calculation of the membrane thickness, degree of hydration of the
membrane, and the mean vesicle aggregation number. The membrane thickness
increases at higher x values, hence the vesicle lumen
must become smaller if the external vesicle dimensions remain constant.
Geometric considerations indicate that this growth mechanism lowers
the total vesicle interfacial area and hence reduces the free energy
of the system. However, it also inevitably leads to gradual ingress
of the encapsulated water molecules into the vesicle membrane, as
confirmed by SAXS analysis. Ultimately, the highly plasticized membranes
become insufficiently hydrophobic to stabilize the vesicle morphology
when x exceeds 1000, thus this PISA growth mechanism
ultimately leads to vesicle “death”.
AGuIX are sub-5 nm nanoparticles made of a polysiloxane matrix and gadolinium chelates. This nanoparticle has been recently accepted in clinical trials in association with radiotherapy. This review will summarize the principal preclinical results that have led to first in man administration. No evidence of toxicity has been observed during regulatory toxicity tests on two animal species (rodents and monkeys). Biodistributions on different animal models have shown passive uptake in tumours due to enhanced permeability and retention effect combined with renal elimination of the nanoparticles after intravenous administration. High radiosensitizing effect has been observed with different types of irradiations in vitro and in vivo on a large number of cancer types (brain, lung, melanoma, head and neck…). The review concludes with the second generation of AGuIX nanoparticles and the first preliminary results on human.
Advances in nanoparticle technology have recently offered new tools to the bioanalytical field of research. In particular, new nanoparticle‐based sensors have appeared able to give quantitative information about different species (ions, metabolites, biomolecules) in biosamples through ratiometric measurements. This article describes the methodologies developed so far in the design of such nanosensors. In particular, the different approaches to immobilize fluorescent chemosensor dyes to nanoparticles are presented. Concept designs of ratiometric nanosensors in terms of composition and architecture are also described and illustrated with examples taken from the literature.
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