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Gold Nanomaterials at Work in Biomedicine *
Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Xuan Yang, Miaoxin Yang, Pang Bo, Madeline Vara, Younan Xia
Either theoretical calculation or numerical simulation can be employed to obtain the extinction, absorption, and scattering cross sections of Au nanostructures. Experimentally, it is far more challenging to measure these optical parameters. In general, the extinction spectra of Au nanostructures can be recorded using a conventional UV-vis-NIR spectrometer. The extinction coefficient can be derived from the particle concentration of a suspension and the extinction measured using a conventional UV-vis-NIR spectrometer. In general, the Beer–Lambert law holds for suspensions of Au nanoparticles at a molar particle concentration of ~10 nM to ensure an optical density in the range of 0.1–1. Given that the concentration of Au nanoparticles can be calculated using the elemental content determined by ICP-MS in conjunction with the physical dimensions obtained by electron microscopy, one can obtain both the optical extinction coefficients and extinction cross sections at different wavelengths [366]. When combined with the computationally derived ratio between the scattering and absorption cross sections, the extinction cross section can then be separated into the two components responsible for scattering and absorption, respectively.
Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
The penetration depth is determined by the extinction coefficient, which characterizes the degree of absorption by individual molecules and concentration of the absorbing molecules by the equation: where ε is the extinction coefficient and c is concentration. The value of the extinction coefficient depends on the wavelength of light being absorbed. This means that the more absorbers present along a given pathway, the shorter the distance light travels before being absorbed – higher concentrations lead to shorter penetration depths. Similarly, the penetration depth is shorter if the extinction coefficient of the material is greater; both depend on wavelength. For example, for green light, blood-filled tissue absorbs light in a shorter distance than tissue containing little blood. Similarly, the lens of the eye has a long penetration depth for visible light. By contrast, visible wavelengths have short penetration depths in the retina, which has a high concentration of strongly absorbing visual pigments.
Chlorpyrifos-Induced Hepatotoxicity and Hematologic Changes in Rat: The Preventive Role of Commiphora mukul
Published in Anne George, Snigdha S. Babu, M. P. Ajithkumar, Sabu Thomas, Holistic Healthcare. Volume 2: Possibilities and Challenges, 2019
Kanika Aggarwal, Devinder Singh
Lactate dehydrogenase (LDH) activity was assayed spectrophoto-metrically in the PtMS by the method reported by Schatz and Segal.30 The results were expressed as μmoles of NADH oxidized/min/mg protein. The extinction coefficient (6.3 χ 103 μmol/L/min) was used to calculate the enzyme activity.
Dual-targeting triplebody 33-16-123 (SPM-2) mediates effective redirected lysis of primary blasts from patients with a broad range of AML subtypes in combination with natural killer cells
Published in OncoImmunology, 2018
Todd A. Braciak, Claudia C. Roskopf, Sarah Wildenhain, Nadja C. Fenn, Christian B. Schiller, Ingo A. Schubert, Uwe Jacob, Annemarie Honegger, Christina Krupka, Marion Subklewe, Karsten Spiekermann, Karl-Peter Hopfner, Georg H. Fey, Michael Aigner, Stefan Krause, Andreas Mackensen, Fuat S. Oduncu
The DNA construct coding for SPM-2 was synthesized by a commercial provider (Eurofins/MWG-Operon). To create this construct, the scFv subunits were disulfide-stabilized78-80 humanized81-83 and stability-engineered84 by standard procedures. The TransIT®-LT1 transfection reagent (Mirus Bio LLC, catalog # MIR 2300) was used for transfection according to the manufacturer´s protocol to generate a stable cell pool of FreestyleTM 293F cells (ThermoFisher Scientific, cat. # R79007) for protein expression. Cells were then cultured under continuous selection with hygromycin C. SPM-2 was captured from cell culture supernatants via its C-terminal hexahistidine tag by immobilized zinc ion affinity chromatography followed by anion exchange chromatography using a 1 ml (bed volume) HiTrap Q Sepharose HP column (GE Healthcare). The third purification step was a cation exchange (CEX) chromatography. Here, a 1 ml HiTrap SP Sepharose HP column (GE Healthcare) was used and connected to an Äkta liquid chromatography system (GE Healthcare). SPM-2 preparations were analyzed by size exclusion chromatography (Superdex S200 5/150 GL column, GE Healthcare) for quality control and by SDS polyacrylamide gel electrophoresis (SDS-PAGE) after the final purification step. The protein concentration was determined by UV absorption at 280 nm using a NanoDrop spectrometer (PeqLab). The theoretical extinction coefficient was calculated from the primary amino acid sequence with the computer program ProtParam (www.expasy.ch). A final yield after purification of approx. 2.5 to 5 mg SPM-2 per L of culture medium was achieved in several independent experiments.
Graphene oxide influence in soil bacteria is dose dependent and changes at osmotic stress: growth variation, oxidative damage, antioxidant response, and plant growth promotion traits of a Rhizobium strain
Published in Nanotoxicology, 2022
Tiago Lopes, Paulo Cardoso, Diana Matos, Ricardo Rocha, Adília Pires, Paula Marques, Etelvina Figueira
Protein carbonylation was determined according to the method described by Mesquita et al. (2014) with modifications proposed by Udenigwe et al. (2016). To 120 μL of supernatant, 120 μL 10 mM 2,4-Dinitrophenylhydrazine (DNPH) was added and incubated for 10 min at room temperature in a plate stirrer. After, 60 μL of 6 M sodium hydroxide (NaOH) was added and incubated for more 10 min in a plate stirrer. The absorbance was measured at 450 nm and the extinction coefficient of DNPH (ε = 22308 M−1 cm−1) was used. Results were expressed in nanomole carbonyl groups per million cells (nmol CG/M cells).
Methotrexate induced mitochondrial injury and cytochrome c release in rat liver hepatocytes
Published in Drug and Chemical Toxicology, 2018
Abdullah Al Maruf, Peter J. O’Brien, Parvaneh Naserzadeh, Rozhina Fathian, Ahmad Salimi, Jalal Pourahmad
H2O2 was measured in hepatocytes by adding FOX1 reagent. The FOX1 reagent consisted of 25 mM sulfuric acid, 250 μM ferrous ammonium sulfate, 100 μM xylenol orange and 100 mM sorbitol. Fifty microliters of hepatocytes suspension were added to 950 μL of the FOX1 reagent and incubated for 30 min at room temperature. Samples were then spectrophotometrically analyzed at 560 nm using an extinction coefficient 2.35 × 105 M−1 cm−1 (Ou & Wolff, 1996). H2O2 values were expressed as nmol/106 cells.