Quantitative comparison of luminescence probes for biomedical applications.

Optical imaging holds great promise for the early-stage detection of diseases. It plays an important role in the process of protecting the patient's health. Most of the organic dyes suffer due to photobleaching, light scattering, short light penetration depth, and autofluorescence of specimen, thus, need to be replaced with alternative nanoprobes emitting light in the optical biological window (700-1350 nm).

Phthalocyanine-Conjugated Upconversion NaYF :Yb /Er @SiO Nanospheres for NIR-Triggered Photodynamic Therapy in a Tumor Mouse Model.

Photodynamic therapy (PDT) has garnered immense attention as a minimally invasive clinical treatment modality for malignant cancers. However, its low penetration depth and photodamage of living tissues by UV and visible light, which activate a photosensitizer, limit the application of PDT. In this study, monodisperse NaYF :Yb /Er nanospheres 20 nm in diameter, that serve as near-infrared (NIR)-to-visible light converters and activators of a photosensitizer, were synthesized by high-temperature co-precipitation of lanthanide chlorides in a high-boiling organic solvent (octadec-1-ene).

Multiband Monte Carlo modeling of upconversion emission in sub 10 nm β-NaGdF:Yb, Er nanocrystals-Effect of Yb content.

In this work, we report the results of theoretical modeling supported and confirmed by experimentally measured emission, emission decay curves, and power dependent emission spectra for sub 10 nm β-NaGdF:Er,Yb nanocrystals with different Yb content (0.5%-15%). For the theoretical analysis, we develop a stochastic Monte Carlo model which is based on two components: (i) formation of clusters composed of Er ion and Yb neighbors, which gives insight into the role of local parameters and (ii) a simplified kinetic model of excitation and relaxation phenomena in pairs of Erand Yb ions.

Size and shape effects in β-NaGdF: Yb, Er nanocrystals.

Three sets of β-NaGdF:Yb, Er nanocrystals (NCs) with different shapes (spherical and more complex flower shapes), different sizes (6-17 nm) and Yb concentrations (2%-15%) were synthesized by a co-precipitation method using oleic acid as a stabilizing agent. The uncommon, single-crystalline flower-shaped NCs were obtained by simply adjusting the fluorine-to-lanthanides molar ratio. Additionally, some of the NCs with different sizes have been covered by the un-doped shell.