In vitro and in vivo investigations of upconversion and NIR emitting Gd2O3:Er3+,Yb3+ nanostructures for biomedical applications

Abstract

The use of an "over 1000-nm near-infrared (NIR) in vivo fluorescence bioimaging" system based on lanthanide containing inorganic nanostructures emitting in the visible and NIR range under 980-nm excitation is proposed. It may overcome problems of currently used biomarkers including color fading, phototoxicity and scattering. Gd(2)O(3):Er(3+),Yb(3+) nanoparticles and nanorods showing upconversion and NIR emission are synthesized and their cytotoxic behavior is investigated by incubation with B-cell hybridomas and macrophages. Surface modification with PEG-b-PAAc provides the necessary chemical durability reducing the release of toxic Gd(3+) ions. NIR fluorescence microscopy is used to investigate the suitability of the nanostructures as NIR-NIR biomarkers. The in vitro uptake of bare and modified nanostructures by macrophages is investigated by confocal laser scanning microscopy. In vivo investigations revealed nanostructures in liver, lung, kidneys and spleen a few hours after injection into mice, while most of the nanostructures have been removed from the body after 24 h.

Er3+ ‐Doped Y2O3 Nanophosphors for Near‐Infrared Fluorescence Bioimaging Applications

“…The mixture was stirred at 50°C for 6 h and the surface‐modified nanoparticles were collected by centrifugation, washed at least three times with distilled water and dried at room temperature. Temperature, time, concentration of polymer, pH, stirring, and sonication parameters were investigated to improve the PEG‐ b ‐PAAc grafting on the surface of nanostructures and was reported in our earlier publications …”

“…The laser power was set to be 5 W with a laser diode (KLD‐6.5 ALT; YAMAKI, Tokyo, Japan). Diagrammatic representation of the NIR imaging setup and further explanation of the in vivo FBI system are given in our recent publication . For the histological analysis, organ samples were fixed with paraffin wax and Hematoxylin–Eosin (H&E) stainings were performed for each samples.…”

“…In recent years, we have been developing NIR–NIR FBI systems by using NIR fluorescence at 1550 nm under 980 nm excitation which can be efficiently emitted from erbium‐ and ytterbium‐doped Gd 2 O 3 /Y 2 O 3 nanoparticles . To apply the UC process to FBI, the desirable size of the RED‐CNP should be less than a few hundred nanometers and the size distribution should be narrow.…”

Upconversion nanoparticles conjugated with curcumin as a photosensitizer to inhibit methicillin-resistant Staphylococcus aureus in lung under near infrared light

“…The UCNPs-curcumin improve the stability of curcumin and will have better effects in vivo. The lung, an internal organ, cannot be affected by visible light, since its penetrating depth is 10 mm; 29 only NIR can reach the lung without harm 30 and become an excellent light source to activate the UCNPs-curcumin in the lung.…”

Preparation and biocompatibilities of luminescent europium-doped yttria and titania nanoparticles

“…Yb 3+ nanoparticles into mice through the tail vein, then the biodistribution was determined using an in vivo fluorescence bioimaging system. 33) 3.3 Photophysical properties of the nanoparticles in the PMMA matrix…”