Endovascular addressing improves the effectiveness of magnetic targeting of drug carrier. Comparison with the conventional administration method.

Many nanomedicine approaches are struggling to reach high enough effectiveness in delivery if applied systemically. The perspective is sought to explore the clinical practices currently used for localized treatment. In this study, we combine in vivo targeting of carriers sensitive to the external magnetic field with clinically used endovascular delivery to specific site. Fluorescent micron-size capsules made of biodegradable polymers and containing magnetite nanoparticles incorporated in the capsule wall were explored in vivo using Near-Infrared Fluorescence Live Imaging for Real-Time. Comparison of systemic (intravenous) and directed (intra-arterial) administration of the magnetic microcapsule targeting in the hindpaw vessels demonstrated that using femoral artery injection in combination with magnetic field exposure is 4 times more efficient than tail vein injection. Thus, endovascular targeting significantly improves the capabilities of nanoengineered drug delivery systems reducing the systemic side effects of therapy.

In Situ Synthesis of Fluorescent Carbon Dots/Polyelectrolyte Nanocomposite Microcapsules with Reduced Permeability and Ultrasound Sensitivity.

Designing and fabricating multifunctional nanocomposite microcapsules are considerable interests in both academic and industrial research aspects. This work first reports an innovative approach to in situ synthesize and assemble fluorescent carbon dots (CDs) into polyelectrolyte microcapsules, obtaining highly biocompatible nanocomposite microcapsules with excellent luminescence that facilitate imaging and identification in vitro, yet with the feasibility to load small molecules and ultrasound responsiveness to trigger their release. CDs are produced in situ in (PAH/PSS)4 microcapsule shells by carbonization of dextran molecules under relatively mild hydrothermal treatment. Compared with the collapsed and film-like (PAH/PSS)4 microcapsules, the novel composite microcapsules show a free-standing structure, smaller size, and thicker shell. CDs are proven to be fabricated and embedded in PAH/PSS multilayers, and the formed PAH/PSS/CD microcapsules are endowed with strong luminescence, as verified by the transmission electron microscopy, fluorescence spectra, and confocal laser scanning microscopy results. The in situ formation of CDs in capsule shells also empowers these capsules with ultrasound responsiveness and reduced permeability. The feasibility of encapsulation of small molecules (rhodamine B) and ultrasound-triggered release is also shown. Most importantly, due to the intrinsic biocompatible property and photostability of CDs, these fluorescent PAH/PSS/CD microcapsules show negligible cell toxicity and low photobleaching, which are impossible for capsules composited with conventional organic dyes and semiconductor quantum dots.