Massively parallel spectroscopy (MPS) of many single nanoparticles in an aqueous dispersion is reported. As a model system, bioconjugated photon-upconversion nanoparticles (UCNPs) with a near-infrared excitation are prepared. The UCNPs are doped either with Tm3+ (emission 450 and 802 nm) or Er3+ (emission 554 and 660 nm). These UCNPs are conjugated to biotinylated bovine serum albumin (Tm3+-doped) or streptavidin (Er3+-doped). MPS is correlated with an ensemble spectra measurement, and the limit of detection (1.6 fmol L-1) and the linearity range (4.8 fmol L-1 to 40 pmol L-1) for bioconjugated UCNPs are estimated. MPS is used for observing the bioaffinity clustering of bioconjugated UCNPs. This observation is correlated with a native electrophoresis and bioaffinity assay on a microtiter plate. A competitive MPS bioaffinity assay for biotin is developed and characterized with a limit of detection of 6.6 nmol L-1. MPS from complex biological matrices (cell cultivation medium) is performed without increasing background. The compatibility with polydimethylsiloxane microfluidics is proven by recording MPS from a 30 μm deep microfluidic channel.

• MeSH
• nanočástice * chemie   MeSH
• spektrální analýza MeSH
• streptavidin MeSH
• umělá inteligence * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• streptavidin MeSH

The detection of cancer biomarkers in histological samples and blood is of paramount importance for clinical diagnosis. Current methods are limited in terms of sensitivity, hindering early detection of disease. We have overcome the shortcomings of currently available staining and fluorescence labeling methods by taking an integrative approach to establish photon-upconversion nanoparticles (UCNP) as a powerful platform for cancer detection. These nanoparticles are readily synthesized in different sizes to yield efficient and tunable short-wavelength light emission under near-infrared excitation, which eliminates optical background interference of the specimen. Here we present a protocol for the synthesis of UCNPs by high-temperature co-precipitation or seed-mediated growth by thermal decomposition, surface modification by silica or poly(ethylene glycol) that renders the particles resistant to nonspecific binding, and the conjugation of streptavidin or antibodies for biological detection. To detect blood-based biomarkers, we present an upconversion-linked immunosorbent assay for the analog and digital detection of the cancer marker prostate-specific antigen. When applied to immunocytochemistry analysis, UCNPs enable the detection of the breast cancer marker human epidermal growth factor receptor 2 with a signal-to-background ratio 50-fold higher than conventional fluorescent labels. UCNP synthesis takes 4.5 d, the preparation of the antibody-silica-UCNP conjugate takes 3 d, the streptavidin-poly(ethylene glycol)-UCNP conjugate takes 2-3 weeks, upconversion-linked immunosorbent assay takes 2-4 d and immunocytochemistry takes 8-10 h. The procedures can be performed after standard laboratory training in nanomaterials research.

• MeSH
• imunosorbenty MeSH
• lidé MeSH
• nádorové biomarkery MeSH
• nádory * diagnóza   MeSH
• nanočástice * chemie   MeSH
• oxid křemičitý chemie   MeSH
• polyethylenglykoly chemie   MeSH
• streptavidin MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• imunosorbenty MeSH
• nádorové biomarkery MeSH
• oxid křemičitý MeSH
• polyethylenglykoly MeSH
• streptavidin MeSH

"All-in-one" multifunctional nanomaterials, which can be visualized simultaneously by several imaging techniques, are required for the efficient diagnosis and treatment of many serious diseases. This report addresses the design and synthesis of upconversion magnetic NaGdF4:Yb3+/Er3+(Tm3+) nanoparticles by an oleic acid-stabilized high-temperature coprecipitation of lanthanide precursors in octadec-1-ene. The nanoparticles, which emit visible or UV light under near-infrared (NIR) irradiation, were modified by in-house synthesized PEG-neridronate to facilitate their dispersibility and colloidal stability in water and bioanalytically relevant phosphate buffered saline (PBS). The cytotoxicity of the nanoparticles was determined using HeLa cells and human fibroblasts (HF). Subsequently, the particles were modified by Bolton-Hunter-neridronate and radiolabeled by 125I to monitor their biodistribution in mice using single-photon emission computed tomography (SPECT). The upconversion and the paramagnetic properties of the NaGdF4:Yb3+/Er3+(Tm3+)@PEG nanoparticles were evaluated by photoluminescence, magnetic resonance (MR) relaxometry, and magnetic resonance imaging (MRI) with 1 T and 4.7 T preclinical scanners. MRI data were obtained on phantoms with different particle concentrations and during pilot long-time in vivo observations of a mouse model. The biological and physicochemical properties of the NaGdF4:Yb3+/Er3+(Tm3+)@PEG nanoparticles make them promising as a trimodal optical/MRI/SPECT bioimaging and theranostic nanoprobe for experimental medicine.

• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Development of upconverting nanomaterials which are able to emit visible light upon near-infrared excitation opens a wide range of potential applications. Because of their remarkable photostability, they are widely used in bioimaging, optogenetics, and optoelectronics. In this work, we demonstrate the influence of several experimental conditions as well as a dopant concentration on the luminescence properties of upconverting nanocrystals (UPNCs) that need to be taken into account for their efficient use in the practical applications. We found that not only nanoparticle architecture affects the optical properties of UPNCs, but also factors such as sample concentration, excitation light power density, and temperature may influence the green-to-red emission ratio. We performed studies on both the single-nanoparticle and ensemble levels over a broad concentration range and found the heterogeneity in the optical properties of UPNCs with low dopant concentrations.

• Publikační typ
• časopisecké články MeSH

Lanthanide-doped upconversion nanoparticles (UCNPs) have a unique capability of upconverting near-infrared (NIR) excitation into ultraviolet, visible, and NIR emission. Conventional UCNPs composed of NaYF4:Yb3+/Er3+(Tm3+) are excited by NIR light at 980 nm, where undesirable absorption by water can cause overheating or damage of living tissues and reduce nanoparticle luminescence. Incorporation of Nd3+ ions into the UCNP lattice shifts the excitation wavelength to 808 nm, where absorption of water is minimal. Herein, core-shell NaYF4:Yb3+/Er3+@NaYF4:Nd3+ nanoparticles, which are doubly doped by sensitizers (Yb3+ and Nd3+) and an activator (Er3+) in the host NaYF4 matrix, were synthesized by high-temperature coprecipitation of lanthanide chlorides in the presence of oleic acid as a stabilizer. Uniform core (24 nm) and core-shell particles with tunable shell thickness (~0.5-4 nm) were thoroughly characterized by transmission electron microscopy (TEM), energy-dispersive analysis, selected area electron diffraction, and photoluminescence emission spectra at 808 and 980 nm excitation. To ensure dispersibility of the particles in biologically relevant media, they were coated by in-house synthesized poly(ethylene glycol) (PEG)-neridronate terminated with an alkyne (Alk). The stability of the NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk nanoparticles in water or 0.01 M PBS and the presence of PEG on the surface were determined by dynamic light scattering, ζ-potential measurements, thermogravimetric analysis, and FTIR spectroscopy. Finally, the adhesive azidopentanoyl-modified GGGRGDSGGGY-NH2 (RGDS) peptide was immobilized on the NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk particles via Cu(I)-catalyzed azide-alkyne cycloaddition. The toxicity of the unmodified core-shell NaYF4:Yb3+/Er3+@NaYF4:Nd3+, NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk, and NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-RGDS nanoparticles on both Hep-G2 and HeLa cells was determined, confirming no adverse effect on their survival and proliferation. The interaction of the nanoparticles with Hep-G2 cells was monitored by confocal microscopy at both 808 and 980 nm excitation. The NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-RGDS nanoparticles were localized on the cell membranes due to specific binding of the RGDS peptide to integrins, in contrast to the NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk particles, which were not engulfed by the cells. The NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-RGDS nanoparticles thus appear to be promising as a new non-invasive probe for specific bioimaging of cells and tissues. This development makes the nanoparticles useful for diagnostic and/or, after immobilization of a bioactive compound, even theranostic applications in the treatment of various fatal diseases.

• Klíčová slova
• 808 nm excitation, Hep-G2 and HeLa cells, PEG-neridronate, RGDS peptide, core-shell, luminescence, upconversion nanoparticles,
• Publikační typ
• časopisecké články MeSH