Surface Functionalisation of Upconversion Nanoparticles with Different Moieties for Biomedical Applications

Abstract

Lanthanide ion-doped upconversion nanoparticles (UCNPs) that can convert low-energy infrared photons into high-energy visible and ultraviolet photons, are becoming highly sought-after for advanced biomedical and biophotonics applications. Their unique luminescent properties enable UCNPs to be applied for diagnosis, including biolabeling, biosensing, bioimaging, and multiple imaging modality, as well as therapeutic treatments including photothermal and photodynamic therapy, bio-reductive chemotherapy and drug delivery. For the employment of the inorganic nanomaterials into biological environments, it is critical to bridge the gap in between nanoparticles and biomolecules via surface modifications and subsequent functionalisation. This work reviews the various ways to surface modify and functionalise UCNPs so as to impart different functional molecular groups to the UCNPs surfaces for a broad range of applications in biomedical areas. We discussed commonly used base functionalities, including carboxyl, amino and thiol moieties that are typically imparted to UCNP surfaces so as to provide further functional capacity.

Preparation and properties of electrospun NaYF4: Yb3+, Er3+‐PLGA‐gelatin nanofibers

“…Furthermore, the FT‐IR spectrum presented C═O stretching vibration peak appeared at 1632 cm −1 , and there was slight shift in the C═O stretching vibration peak compared with pure oleic acid (1711 cm −1 ), which was consistent with the results reported in some previous literatures 27–29 . This could be attributed to the lateral interaction and ordered effect of the long chain structure of oleic acid molecules, which has a strong effect on the C═O stretching vibration peak of the longer carboxyl group, thus causing the deviation of the diffraction peak position 30,31 . The fabricated NaYF 4 NPs were covered with oleic acid molecules which might induce the surface hydrophobicity.…”

“…[27][28][29] This could be attributed to the lateral interaction and ordered effect of the long chain structure of oleic acid molecules, which has a strong effect on the C═O stretching vibration peak of the longer carboxyl group, thus causing the deviation of the diffraction peak position. 30,31 The fabricated NaYF 4 NPs were covered with oleic acid molecules which might induce the surface hydrophobicity.…”

Monodisperse Core-Shell NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-GGGRGDSGGGY-NH2 Nanoparticles Excitable at 808 and 980 nm: Design, Surface Engineering, and Application in Life Sciences

“…Such polymers include poly(acrylic acid), poly(ethylene glycol) (PEG) and its derivatives (e.g., PEG-neridronate), poly(vinylpyrrolidone), polyethyleneimine, poly(maleic anhydride-alt-1-octadecene), chitosan, dextran, etc. (Wilhelm et al, 2015;Gee and Xu, 2018;Mandl et al, 2019;Patsula et al, 2019).…”

Latest Trends in Lateral Flow Immunoassay (LFIA) Detection Labels and Conjugation Process

“…A series of functionalization methods have been developed in order to overcome the instability of UCNPs in aqueous solutions and to introduce functional groups on their surface, for the binding of different biomolecules. The main strategies are: ligand modification; layer-by-layer assembly; ligand attraction; and polymerization ( Gee and Xu, 2018 ).…”