Oleyl-hyaluronan micelles loaded with upconverting nanoparticles for bio-imaging

Abstract

Hyaluronan (HA) represents an interesting polymer for nanoparticle coating due to its biocompatibility and enhanced cell interaction via CD44 receptor. Here, we describe incorporation of oleatecapped b-NaYF 4 :Yb 3? , Er 3? nanoparticles (UCNP-OA) into amphiphilic HA by microemulsion method. Resulting structures have a spherical, micelle-like appearance with a hydrodynamic diameter of 180 nm. UCNP-OA-loaded HA micelles show a good stability in PBS buffer and cell culture media. The intensity of green emission of UCNP-OA-loaded HA micelles in water is about five times higher than that of ligand-free UCNP, indicating that amphiphilic HA effectively protects UCNP luminescence from quenching by water molecules. We found that UCNP-OA-loaded HA micelles in concentrations up to 50 lg mL -1 increase cell viability of normal human dermal fibroblasts (NHDF), while viability of human breast adenocarcinoma cells MDA-MB-231 is reduced at these concentrations. The utility of UCNP-OA-loaded HA micelles as a bio-imaging probe was demonstrated in vitro by successful labelling of NHDF and MDA-MB-231 cells overexpressing the CD44 receptor. NHDF (d) incubated with UCNP-OA-loaded oleyl-HA micelles and excess of oleyl-HA (2 mg mL -1 ) served as controls. Green and blue colours represent upconversion emission and Hoechststained cell nuclei, respectively. (Color figure online)

Synthesis of NaGdF4:Er3+/Yb3+ Upconversion Particles as Exogenous Contrast Agent for Swept-Source Optical Coherence Tomography: In Vitro Animal Tissue Imaging

“…The TG analysis provides a shred of additional evidence that samples are capped with organic moieties. 38 Samples were also tested for colloidal stability, and the recorded zeta potential curves are shown in Figure 5a. The zeta potential of ethanol-dispersed NaGdF-I and NaGdF-II samples is recorded as +14.9 mV and −15.9 mV, respectively.…”

Widefield imaging of upconverting nanoparticles on epifluorescence microscopes adapted for laser illumination with top-hat profile

“…Nanocrystals of β-NaY 0.80 Yb 0.18 Er 0.02 F 4 capped with oleic acid were synthesized through a thermal decomposition of corresponding rare-earth oleates; details of the synthesis are described in our previous work. 29 An aliquot of chloroform colloid of purified UCNP was then mixed with polyvinylpyrrolidone (PVP) with molecular weight of 2 MDa. The particle to PVP weight ratio was 1:3.…”

“…Finally, water-soluble micelles were prepared by combining peptide-bearing oleylhyaluronan derivative with UCNP-OA (mean diameter 25 nm) by the procedure described previously. 29 Micelles without peptide were also prepared as a control.…”

“…A detailed synthesis of UCNP and their following incorporation into amphiphilic HA derivatives were reported elsewhere. 29 Electron microscopy and dynamic light scattering (DLS) were used to characterize size and morphology of UCNP incorporated into oleyl-hyaluronan micelles bearing targeting peptide. Drystate STEM revealed UCNP clusters within polymer particles of oleyl-hyaluronan derivative with diameter 56 AE 14 nm [ Fig.…”

Optimization of cell growth on palmitoyl‐hyaluronan knitted scaffolds developed for tissue engineering applications

“…For example, esterification of HA with fatty acid residues could be applied to prepare water‐insoluble fibers . Good biocompatibility of this material was confirmed in vitro as this type of HA modification has been tested as a drug delivery carrier, coating of luminescent upconverting nanoparticles, non‐adhesive thin‐film for TE or in vivo in a form of SPION‐loaded carrier system . However, the surface interaction of these fibers with cellular components was highly restricted.…”