Toxicity Of Upconversion Nanoparticles Research Articles

Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells.

Upconversion nanoparticles (UCNPs), consisting of NaYF4 doped with 18% Yb and 2% Er, were coated with microporous silica shells with thickness values of 7 ± 2 and 21 ± 3 nm. Subsequently, the negatively charged particles were functionalized with N-(6-aminohexyl)-3-aminopropyltrimethoxysilane (AHAPS), which provide a positive charge to the nanoparticle surface. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements revealed that, over the course of 24h, particles with thicker shells release fewer lanthanide ions than particles with thinner shells. However, even a 21 ± 3 nm thick silica layer does not entirely block the disintegration process of the UCNPs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and cell cytometry measurements performed on macrophages (RAW 264.7 cells) indicate that cells treated with amino-functionalized particles with a thicker silica shell have a higher viability than those incubated with UCNPs with a thinner silica shell, even if more particles with a thicker shell are taken up. This effect is less significant for negatively charged particles. Cell cycle analyses with amino-functionalized particles also confirm that thicker silica shells reduce cytotoxicity. Thus, growing silica shells to a sufficient thickness is a simple approach to minimize the cytotoxicity of UCNPs.

Токсичность апконверсионных наночастиц. Обзор

Background and Objectives: The object of the study was the toxicity of upconversion nanoparticles. The aim is to overview the literature on the toxicity of various types of upconversion nanoparticles and to search for their maximum permissible concentration when administered to laboratory animals in vivo. Materials and Methods: The approach used has been the analysis of recent publications on the topic. Results: Upconversion particles are promising for visualization of the structure of biological tissues and organs in fluorescent light, as well as for use in diagnostics of diseases and photoinduced therapy. Nanoparticles with additional shells or functionalized by surface coating with targeted or photoactive molecules, allowing the creation of particles with several modalities, are considered. The phototoxicity of such particles is considered separately. When using nanoparticles for therapy or diagnostics of the state of living objects, the issue of toxicity is urgent. The toxic effect of upconversion nanoparticles on the body depends on their concentration upon administration, as well as on the total amount of nanoparticles correlated with the body weight. Conclusion: From the considered concentration dependences, based on the results of histological and biochemical studies, it was shown that, as a rule, no noticeable toxicity was observed in such particles, and the maximum permissible concentration of particles can be considered 2 mg/ml.

Upconversion nanoparticle as a theranostic agent for tumor imaging and therapy

Upconversion nanoparticles (UCNPs) as a promising material are widely studied due to their unique optical properties. The material can be excited by long wavelength light and emit visible wavelength light through multiphoton absorption. This property makes the particles highly attractive candidates for bioimaging and therapy application. This review aims at summarizing the synthesis and modification of UCNPs, especially the applications of UCNPs as a theranostic agent for tumor imaging and therapy. The biocompatibility and toxicity of UCNPs are also further discussed. Finally, we discuss the challenges and opportunities in the development of UCNP-based nanoplatforms for tumor imaging and therapy.