Versatile Bioconjugation Strategies of PEG-Modified Upconversion Nanoparticles for Bioanalytical Applications

Abstract

Lanthanide-doped upconversion nanoparticles (UCNPs) display highly beneficial photophysical features for background-free bioimaging and bioanalysis; however, they are instable in high ionic strength buffers, have no functional groups, and are nonspecifically interacting. Here, we have prepared NIR-excitable UCNPs that are long-term colloidally stable in buffered media and possess functional groups. Heterobifunctional poly(ethylene glycol) (PEG) linkers bearing neridronate and alkyne or maleimide were attached to UCNPs via a ligand exchange. Streptavidin (SA)-

Poly(N,N-dimethylacrylamide)-Coated Upconverting NaYF4:Yb,Er@NaYF4:Nd Core-Shell Nanoparticles For Fluorescent Labeling of Carcinoma Cells

“…The OA-stabilized CS-UCNP were ellipsoidal (Fig. 4b), in agreement with earlier described results [37].…”

“…Surface of the CS-UCNP was modi ed by Ner-PEG according to an earlier published report [37]. Ner-PEG (3.5 mg) was added to an aqueous dispersion of CS-UCNP (6 ml; 1.7 mg/ml) and the mixture was stirred at RT for 12 h. Resulting CS-UCNP@Ner-PEG were dialyzed against water using a cellulose membrane (MWCO 14 kDa) to remove excessive PEG-Ner.…”

Cationic Polymer-Coated Magnetic Nanoparticles with Antibacterial Properties: Synthesis and In Vitro Characterization

“…Morphology, size, and size distribution of the particles were analyzed with a Tecnai G2 Spirit Twin 12 transmission electron microscope (TEM; FEI; Brno, Czech Republic) [ 10 ]. Number-average diameter ( D n = ΣN i ∙D i /ΣN i ), weight-average diameter ( D w = ΣN i ∙D i 4 /ΣN i ∙D i 3 ), and dispersity ( Ð = D w / D n ) were calculated from at least 500 individual particles from the TEM micrographs using Atlas software (Tescan, Brno, Czech Republic).…”

“…Morphology, size, and size distribution of the particles were analyzed with a Tecnai G2 Spirit Twin 12 transmission electron microscope (TEM; FEI; Brno, Czech Republic) [10].…”

“…In a search for new, cheap, and simple solutions of these problems, a significant effort has been devoted to the development of antibacterial agents based on nanoparticles [ 5 , 6 , 7 ]. In contrast to conventional antibiotics, such materials possess a range of unique physicochemical and biological properties, e.g., high surface-to-volume ratio that increases contact area with microorganisms, high stability, possibility of easy modification with various functional groups, ligands, targeting agents and other biomolecules, enabling not only disinfection, but also its monitoring and targeting [ 8 , 9 , 10 ]. Particles possessing sterilization properties are typically based on silver, copper, various metal oxides or sulfides, or carbon nanotubes [ 11 ].…”