Nanotoxicological Assessments of Upconversion Nanoparticles

Upconversion nanoparticles (UCNPs) are highly efficient luminescent nanomaterials with emission in the visible spectra while being excited by near-infrared region light (NIR). With their unique properties such as high luminescence intensity, sharp emission peaks with narrow bandwidth, large anti-Stokes’ shift, and sizes smaller than 100 nm, UCNPs have emerged as promising candidates for diverse biomedical applications such as cancer detection and therapy, fluorescence imaging, magnetic resonance imaging (MRI), and drug delivery. The UCNPs are composed of a crystalline matrix doped with lanthanide ions that can absorb NIR light (~980 nm) and upconvert it to visible light. However, to achieve successful biomedical applications, proper functionalization, target-specific cell interaction, and biocompatibility are critical factors that must be considered. Additionally, a comprehensive nanotoxicological assessment is necessary to ensure that UCNPs are not cytotoxic or genotoxic. This assessment is particularly important for long-term studies of nanoparticles’ tracking in vivo. Therefore, this chapter aims to provide an in-depth evaluation of the nanotoxicological issues related to nanoparticles (NPs) and UCNPs in biomedical applications, and ensure their safety and efficacy as bioimaging and chemotherapeutic delivery tools

Nanotoxicological Assessments of Upconversion Nanoparticles

https://www.intechopen.com/online-first/nanotoxicological-assessments-of-upconversion-nanoparticlesUpconversion nanoparticles (UCNPs) are highly efficient luminescent nanomaterials with emission in the visible spectra while being excited by near-infrared region light (NIR). With their unique properties such as high luminescence intensity, sharp emission peaks with narrow bandwidth, large anti-Stokes’ shift, and sizes smaller than 100 nm, UCNPs have emerged as promising candidates for diverse biomedical applications such as cancer detection and therapy, fluorescence imaging, magnetic resonance imaging (MRI), and drug delivery. The UCNPs are composed of a crystalline matrix doped with lanthanide ions that can absorb NIR light (~980 nm) and upconvert it to visible light. However, to achieve successful biomedical applications, proper functionalization, target-specific cell interaction, and biocompatibility are critical factors that must be considered. Additionally, a comprehensive nanotoxicological assessment is necessary to ensure that UCNPs are not cytotoxic or genotoxic. This assessment is particularly important for long-term studies of nanoparticles’ tracking in vivo. Therefore, this chapter aims to provide an in-depth evaluation of the nanotoxicological issues related to nanoparticles (NPs) and UCNPs in biomedical applications, and ensure their safety and efficacy as bioimaging and chemotherapeutic delivery tools. RESUMEN Las nanopartículas de conversión ascendente (UCNP) son nanomateriales luminiscentes altamente eficientes con emisión en el espectro visible mientras son excitados por la luz de la región del infrarrojo cercano (NIR). Con sus propiedades únicas, como alta intensidad de luminiscencia, picos de emisión agudos con ancho de banda estrecho, gran desplazamiento anti-Stokes y tamaños inferiores a 100 nm, las UCNP se han convertido en candidatos prometedores para diversas aplicaciones biomédicas, como la detección y terapia del cáncer, imágenes de fluorescencia. , imágenes por resonancia magnética (MRI) y administración de medicamentos. Las UCNP están compuestas por una matriz cristalina dopada con iones de lantánidos que pueden absorber la luz NIR (~980 nm) y convertirla en luz visible. Sin embargo, para lograr aplicaciones biomédicas exitosas, la funcionalización adecuada, la interacción celular específica y la biocompatibilidad son factores críticos que deben considerarse. Además, es necesaria una evaluación nanotoxicológica integral para garantizar que las UCNP no sean citotóxicas ni genotóxicas. Esta evaluación es particularmente importante para estudios a largo plazo sobre el seguimiento de nanopartículas in vivo. Por lo tanto, este capítulo tiene como objetivo proporcionar una evaluación en profundidad de los problemas nanotoxicológicos relacionados con las nanopartículas (NP) y las UCNP en aplicaciones biomédicas, y garantizar su seguridad y eficacia como herramientas de bioimagen y administración quimioterapéutica

Aminosilane Functionalization and Cytotoxicity Effects of Upconversion Nanoparticles Y2O3 and Gd2O3 Co-doped with Yb3+and Er3+

In this study, luminescent upconversion nanoparticles (UCNPs) Y2O3 and Gd2O3 co-doped with Yb3+ and Er3+ were prepared by the sol-gel method (SG). These NPs are able to absorb near infrared photons and upconvert them into visible radiation with a direct application in bioimaging, as an important tool to diagnose and visualize cancer cells. The UCNPs were coated with a thin silica shell and functionalized with amino groups for further folic acid conjugation to allow their interaction with folate ligands on the cell surface. Their physical properties were analysed by Transmission Electron Microscopy (TEM), Fourier trans‐ form infrared spectroscopy (FTIR) and photoluminescence (PL) measurements. The PL results revealed excellent luminescence properties on all core-shell UCNPs. Cytotox‐ icity experiments with concentrations of bare and amino‐ silane coated/functionalized UCNPs between 0.001 μg/mL to 1 μg/mL were tested on two different cell lines from human cervix carcinoma (HeLa) and human colorectal adenocarcinoma (DLD-1) with a colorimetric assay based on the reduction of MTT reagent (methy-134-thiazolylte‐ trazolium). The assays show that some concentrations of bare UCNPs were cytotoxic for cervical adenocarcinoma cells (HeLa); however, for human colorectal adenocarcino‐ ma all UCNPs are non-cytotoxic. After UCNPs functional‐ ization with silica-aminosilane (APTES/TEOS), all of the nanoparticles tested were found to be non-cytotoxic for both cell lines. The UCNPs functionalized in this work can be further conjugated with specific ligands and used as biolabels for detection of cancer cells

EPR and LC-MS studies on the mechanism of industrial dye decolorization by versatile peroxidase from Bjerkandera adusta

The mechanisms of industrial dye transformation by versatile peroxidase were elucidated. Purified versatile peroxidase from Bjerkandera adusta was able to decolorize different classes of dyes including azo and phthalocyanines, but unable to transform any of the anthraquinones tested. Kinetic constants for selected dyes were determined and the transformation products were analyzed by EPR spectroscopy and mass spectrometry. The EPR and MS analyses of the enzymatic decolorization products showed the cleavage of the azo bond in azo dyes and the total disruption of the phthalocyaninic ring in phthalocyanine dyes. The EPR analysis on two coppercontaining dyes, reactive violet 5 (azo) and reactive blue 72 (phthalocyanine), showed that the transformation can or not break the metal-ion coordination bond according the dye nature. The role of the catalytic Trp172 in the dye transformation by a long-range electron transfer pathway was confirmed and the oxidation mechanisms are proposed and discussed

Tryptophan-surface modification of versatile peroxidase from Bjerkandera adusta enhances its catalytic performance

Versatile peroxidase (VP) from the fungus Bjerkandera adusta is able to transport electrons from a catalytic tryptophan residue placed in the protein surface to the activated heme prosthetic group by a long range electron transfer (LRET) process. In this work, the protein surface of VP was covalently modified with tryptophan (W-VP) in order to increase the number of catalytic sites on the protein surface. The W-VP preparation showed an increase of 47% in the catalytic activity (kcat) with 2,6-dimethoxyphenol (DMP) and no change in the catalytic efficiency (kcat/KM). Importantly, the transformation of bulky substrate, Remazol Brilliant Blue R (RBBR), showed an increase of 60% for the kcat value and two-times higher value of kcat/KM. The activity on manganese II was drastically reduced in the modified preparation (W-VP) due to the disruption of the manganese coordination site in the protein. The creation of new superficial catalytic sites after Trp modification is supported by the EPR analysis of radical formation, and by 54% higher operational stability of W-VP in the transformation of bulky substrates. The effect of the covalent modification of the VP protein surface and the mechanism for enhanced activity and operational stability are discussed

Exploring In Vitro Biological Cellular Responses of Pegylated β-Cyclodextrins

βCDPEG5 and βCDPEG2 are two derivatives comprising seven PEG linear chains of 5 and 2 kDa, respectively, conjugated to βCD. As βCDPEGs display different physicochemical properties than their precursors, they could also trigger distinct cellular responses. To investigate the biological behavior of βCDPEGs in comparison to their parent compounds, we performed broad toxicological assays on RAW 264.7 macrophages, MC3T3-E1 osteoblasts, and MDCK cells. By analyzing ROS and NO2− overproduction in macrophages, we found that βCDPEGs induced a moderate stress response without affecting cell viability. Although MC3T3-E1 osteoblasts were more sensitive than MDCK cells to βCDPEGs and the parent compounds, a similar pattern was observed: the effect of βCDPEG5 on cell viability and cell cycle progression was larger than that of βCDPEG2; PEG2 affected cell viability and cell cycle more than βCDPEG2; cell post-treatment recovery was favorable in all cases, and the compounds had similar behaviors regarding ROS generation. The effect on MDCK cell migration followed a similar pattern. In contrast, for osteoblasts, the interference of βCDPEG5 with cell migration was smaller than that of βCDPEG2; likewise, the effect of PEG2 was shorter than its conjugate. Overall, the covalent conjugation of βCD and PEGs, particularly to yield βCDPEG2, improved the biocompatibility profile, evidencing that a favorable biological response can be tuned through a thoughtful combination of materials. Moreover, this is the first time that an in vitro evaluation of βCD and PEG has been presented for MC3T3-E1 and MDCK cells, thus providing valuable knowledge for designing biocompatible nanomaterials constructed from βCD and PEGs

Highly Antifungal Activity of Biosynthesized Copper Oxide Nanoparticles against <i>Candida albicans</i>

Candida albicans (ATCC SC5314) was exposed to biosynthesized copper oxide nanoparticles (CuONPs) to determine their inhibitory capacity. Nanoparticles were polydisperse of small size (5.8 ± 3.5 nm) with irregular shape. The minimum inhibitory concentration (MIC) against C. albicans was 35.5 µg/mL. The production of reactive oxygen species (ROS) of C. albicans was verified when exposed to different concentrations of CuONPs. Ultrastructural analysis of C. albicans revealed a high concentration of CuONPs in the cytoplasm and outside the cell; also, nanoparticles were detected within the cell wall. Cytotoxic analyses using fibroblasts (L929), macrophages (RAW 264.7), and breast (MCF-12) cell lines show good results of cell viability when exposed at the MIC. Additionally, a hemocompatibility analysis was carried out and was found to be below 5%, considered the threshold for biocompatibility. Therefore, it is concluded that the biosynthesized CuONPs have a high potential for developing a topical antifungal treatment

Design of a VLP-nanovehicle for CYP450 enzymatic activity delivery

Background: The intracellular delivery of enzymes for therapeutic use has a promising future for the treatment of several diseases such as genetic disorders and cancer. Virus-like particles offer an interesting platform for enzymatic delivery to targeted cells because of their great cargo capacity and the enhancement of the biocatalyst stability towards several factors important in the practical application of these nanoparticles. Results: We have designed a nano-bioreactor based on the encapsulation of a cytochrome P450 (CYP) inside the capsid derived from the bacteriophage P22. An enhanced peroxigenase, CYPBM3, was selected as a model enzyme because of its potential in enzyme prodrug therapy. A total of 109 enzymes per capsid were encapsulated with a 70% retention of activity for cytochromes with the correct incorporation of the heme cofactor. Upon encapsulation, the stability of the enzyme towards protease degradation and acidic pH was increased. Cytochrome P450 activity was delivered into Human cervix carcinoma cells via transfecting P22-CYP nanoparticles with lipofectamine. Conclusion: This work provides a clear demonstration of the potential of biocatalytic virus-like particles as medical relevant enzymatic delivery vehicles for clinical applications