Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Reproducibility of the capsaicin-induced dermal blood flow response as assessed by laser Doppler perfusion imaging

What is already known about this subjectCapsaicin rapidly produces local neurogenic inflammation (characterized by oedema and erythema) when locally administered to the human skin by binding to the TRPV1 receptor present on dermal sensory nerve endings.In nonhuman primates, a pharmacodynamic assay has been described and validated using capsaicin-induced dermal vasodilation measured by laser Doppler perfusion imaging to assess calcitonin gene-related peptide antagonist activity.Laser Doppler perfusion imaging has also been shown to be a reliable method for characterizing microvascular changes in the human skin.What this study addsCapsaicin induces a reproducible within-subject arm-to-arm increase in dermal blood flow (DBF) when applied to the human skin.This is the first study to describe a non-invasive pharmacodynamic model in humans using capsaicin-induced neurogenic inflammation and allowing repeated, reproducible measurements of DBF to be performed.This model might therefore be utilized in the early clinical evaluation of antagonists of putative mediators involved in capsaicin-induced dermal vasodilation

Optical Monitoring

SCOPUS: ch.binfo:eu-repo/semantics/publishe