Folic acid-conjugated chromium(III) doped nanoparticles consisting of mixed oxides of zinc, gallium and tin, and possessing near-infrared and long persistent phosphorescence for targeted imaging of cancer cells

Abstract

Folic acid-conjugated luminescent nanomaterials have long been widely used in targeted bioimaging, often simultaneously acting as vehicles for drug delivery. They often require, however, intense light sources for photoexcitation, and this often results in photobleaching, strong luminescence background, and strong light scattering. This article describes the preparation of nanoparticles (NPs) of the type Zn 1.1 Ga 1.8 Sn 0.1 O 4 doped with Cr(III) ions and surfacemodified with folic acid. The functionalization of the NPs was monitored via measurement of zeta potentials, FTIR spectra and thermogravimetry. Cell viability and biocompatibility were tested using the MTT kit. The NPs have a size of 220 nm and were characterized by dynamic X-ray diffraction, light scattering, field emission scanning electron microscopy and high-resolution transmission electron microscopy. After annealing the NPs for 10 min at 300°C and irradiating them with 254 nm light for 10 min, they display deep red emission that persists for up to 10 h. The NPs are easily dispersed, small-sized, and crystalline. In our perception, the new material with its long decay time offers quite novel features in terms of targeted optical imaging in providing high resolution, weak disturbance by background luminescence, and the absence of light scattering. They were successfully applied to image MCF-7 and A549 cells.

Near-infrared long-persistent phosphor of Zn3Ga2Ge2O10: Cr3+ sintered in different atmosphere

“…Since their emissions are in the region of the biologically transparent window (650-1100 nm) [12,13], moreover, since the emission lifetime is sufficiently long to permit late time-gated imaging, long persistent phosphors (LPPs) are unique and superior to other labels [14][15][16][17][18]. In such a case, auto-fluorescence from tissue organic components during imaging can be completely avoided, which gives rise to an extraordinary high signal-to-noise ratio [19,20].…”

Dual mode NIR long persistent phosphorescence and NIR-to-NIR Stokes luminescence in La3Ga5GeO14: Cr3+, Nd3+ phosphor

“…and the entire, rapid, high-resolution and signal to noise ratio imaging to be taken in a long-term tracing [4][5][6]. To date, various novel fluorescent tags such as fluorescent dyes, semiconductor quantum dots, upconversion phosphors, and long persistent phosphors (LPPs) have been proposed and successfully applied in in vivo bio-imaging [7][8][9][10]. Among these fluorescent tags, long persistent phosphors in the region of biologically transparent window region (650-1100 nm) have been considered to be the most prominent candidates for this advanced biomedical application, since their emission lifetime is sufficiently long to permit late time-gated imaging [11][12][13].…”

SrAl12O19: Fe3+ @3‐aminopropyl triethoxysilane: Ambient aqueous stable near‐infrared persistent luminescent nanocomposites

“…Furthermore, if the operation waveband of PLNPs falls within the tissue transparency window in near-infrared (NIR) optical region, near-infrared PLNPs (N-PLNPs) can endow a long-term in vivo imaging with deeper tissue penetration and higher signal to noise ratio. [7][8][9][10] Therefore, increasing attention has been focused on the development of N-PLNPs. To date, some N-PLNPs have been successfully applied in nonbackground bio-imaging and detections, deep-tissue photodynamic therapy, and long-term biomolecule tracking.…”

“…Due to their unique optical property that no real‐time excitations required, PLNPs demonstrated exceptional performance in various industrial, biomedical, and ecological applications. Furthermore, if the operation waveband of PLNPs falls within the tissue transparency window in near‐infrared (NIR) optical region, near‐infrared PLNPs (N‐PLNPs) can endow a long‐term in vivo imaging with deeper tissue penetration and higher signal to noise ratio . Therefore, increasing attention has been focused on the development of N‐PLNPs.…”