Polymeric nanoparticles with tunable architecture formed by biocompatible star shaped block copolymer

An amphiphilic star shaped block copolymer, based on well known biocompatible components, was synthesized using branched poly(ε-caprolactone) as hydrophobic core and branched poly(ethyleneglycol) as hydrophilic corona. The composition of this macromolecule, based on two well differentiated blocks, conferred amphiphilic behavior to the whole system that acted as driving force for its self-assembling in aqueous media. Depending on the polymer concentration it was possible to obtain different architectures. The TEM micrographs permitted to follow the evolution of the system from single vesicles toward necklace entanglements. In this work, we discuss the mechanism that would be involved in the evolution of the system's morphology as a function of the block copolymer concentration. In addition, the proposed star shaped block copolymer presented good solubilizing properties that were used to disperse in water, poorly soluble molecules such as chlorine-carbazoles, which were used to investigate the suitability of the self-assembled nanostructures as drug nano-carriers.     

Infrared fluorescence imaging of infarcted hearts with Ag2S nanodots

Ag₂S nanodots have already been demonstrated as promising near-infrared (NIR-II, 1.0–1.45 μm) emitting nanoprobes with low toxicity, high penetration and high resolution for in vivo imaging of, for example, tumors and vasculature. In this work, we have systematically investigated the potential application of functionalized Ag₂S nanodots for accurate imaging of damaged myocardium tissues after a myocardial infarction induced by either partial or global ischemia. Ag₂S nanodots surface-functionalized with the angiotensin II peptide (ATII) have shown over 10-fold enhanced binding efficiency to damaged tissues than non-specifically (PEG) functionalized Ag₂S nanodots due to their interaction with the upregulated angiotensin II receptor type I (AT1R). It is demonstrated how the NIR-II images generated by ATII-functionalized Ag₂S nanodots contain valuable information about the location and extension of damaged tissue in the myocardium allowing for a proper identification of the occluded artery as well as an indirect evaluation of the damage level. The potential application of Ag₂S nanodots in the near future for in vivo imaging of myocardial infarction was also corroborated by performing proof of concept whole body imaging experiments.