Biofunctionalization, cytotoxicity, and cell uptake of lanthanide doped hydrophobically ligated NaYF4 upconversion nanophosphors

Abstract

Surface biofunctionalization of the hydrophobic lanthanide ion doped hexagonal phase NaYF4:Yb,Er upconversion nanophosphors (UCNPs) was achieved by introducing amino and carboxyl groups, respectively. Amino groups were added by using the 3-aminopropyltrimethoxysilane reaction after a thin layer of SiO2 coating. The carboxyl groups on surface were added directly by coating modified amphiphilic polyacrylic acid polymer. Experimental studies of cytotoxicity and cell uptake of UCNPs were conducted. The cytotoxicity analysis of the functionalized UCNPs was conducted by methylthiazol tetrazolium assays. Cell uptake was accomplished by incubating the UCNPs with human osteosarcoma cells and proved by transmission electron microscopy. The results showed that the functionalized UCNPs had very low toxicity compared with the control group, while UCNPs taken into the cells indicated that they had very high biocompatibility. The imaging of UCNPs, which were incubated with AB12 mouse mesothelioma cells and excited by 1 W 980 nm light, showed individual particles with visible light emission. These results exhibited promising applications of functionalized UCNPs in cell imaging and photodynamic therapy.

Optically stimulated heating using Nd3+ doped NaYF4 colloidal near infrared nanophosphors

“…The LHT relays on the introduction of small, nanometersize particles that are responsible for converting the delivered energy (i.e., photons, magnetic field) into heat, which is further transferred to the surrounding cells/tissue. The spatial localization is usually achieved by biofunctionalization of the nanoparticles (NPs) surface with antigens [7,9,10]. Biofunctionalized gold nanostructures (nanorods [11], nanocubes [12], nanocages [13,14], nanoshells [15] as well as hybrid Au-Fe3O4 [16]) or graphene [17] have been successfully applied as nanoheaters in many in-vitro studies and allowed to diminish most of the drawbacks of the original method.…”

“…A significant improvement in the management of HT treatment has been achieved with a LHT treatment [6][7][8]. The LHT relays on the introduction of small, nanometersize particles that are responsible for converting the delivered energy (i.e., photons, magnetic field) into heat, which is further transferred to the surrounding cells/tissue.…”

Dendritic upconverting nanoparticles enable in vivo multiphoton microscopy with low-power continuous wave sources

“…Conversely, UCNPs are commonly produced as complexes with hydrophobic capping ligands (23)(24)(25)(26), which later must be replaced by hydrophilic shells. Efforts toward obtaining water-soluble nanoparticles encompass exchange of the capping ligands for various macromolecules (27,28), encapsulation into SiO 2 layers and their subsequent modification (29)(30)(31), as well as wrapping of hydrophobic UCNPs with amphiphilic polymers (32). Overall, despite the significant progress, suboptimal stability of hydrophilic UCNPs still presents a major problem.…”

Nanopartikel für die Aufwärtskonversion

“…[42,45,62,201,221,246,464] Um die so modifizierten Partikel anschließend an Biomoleküle zu binden, sind reaktive Reste wie Amino-oder Carboxygruppen erforderlich. Im Fall von SiO 2 -beschichteten Partikeln können biofunktionale Aminogruppen durch die Reaktion der SiO 2 -Oberfläche mit 3-Aminopropyltrimethoxysilan eingeführt werden, wie Shan und Ju gezeigt haben.…”