Uv vis spectrometer

Functional status of cell-free synthesized proteins was tested by mobility-shift assay using promoter-operator regions of T. maritima and E. coli. A putative promoter-operator region was obtained by PCR using IRDye-labeled primers (Supplementary Table S2) as described previously [28 (link)]. His-labeled proteins were diluted in binding buffer 10 mM Tris-HCl (pH 7.5), 250 mM KCl, 5 mM MgCl₂, 2.5 mM CaCl₂, 2.5% glycerol,0.5 mM DTT and then incubated labeled target DNA in the presence of a 100-fold of unlabeled sonicated herring sperm DNA at 37 °C for 30 min. Samples were loaded on a 2% (w/v) agarose gel prepared in TAE buffer (40 mM Tris-base (pH 8), 10 mM sodium acetate, 1 mM EDTA) and electrophoresed at room temperature at 12 V cm⁻¹ for one hour. DNA fragments were transferred from gels onto a nylon membrane (Qiagen). The concentration of labeled DNAs was measured with a UV/VIS spectrometer (Perkin Elmer, Villebon-sur-Yvette, France) and by comparison of fluorescent DNA bands in an agarose gel.

UV-vis spectroscopy was performed on the aqueous dispersions of AuNPs, in quartz cuvettes with 1 and 0.1 cm optical path length, in the wavelength range 200–700 nm, at 25 °C, with a spectral resolution of 1 nm on a Perkin Elmer UV-vis spectrometer (Lambda 2S, Waltham, MA, USA). Samples were pre-equilibrated prior to the initial scan for 2 min at RT. Particle size analysis was performed by dynamic light scattering (Horiba LB-550, Kyoto, Japan) and the results were presented as the mean of at least three measurements.

NMR spectra were recorded using a Bruker Avance DRX 400 spectrometer. Chemical shifts are reported in ppm with solvent as internal reference. Electronic absorption spectra were recorded using a PerkinElmer UV/Vis spectrometer.

The blood compatibility of the three redox-sensitive micelles was estimated by hemolysis assay. Succinctly, the obtained red blood cells (RBCs) were centrifuged at 4000 rpm for 5 min followed by resuspending with saline to obtain 2% suspension. Then equal volumes of RBCs suspensions (2%) were mixed with blank LC-Cys-OA, LC-Cys-DA or LC-Cys-CA micelles at the range of 0.5–2.0 mg/mL and incubated for 1 h in a thermostatic water bath at 37 °C. In parallel, a NaCl solution (0.9%) and deionized water were regarded as negative and positive control groups, which were treated with the same condition as the samples. Finally, all samples were measured using a UV-vis spectrometer (PerkinElmer, Waltham, MA, USA) at 540 nm. The hemolysis rate was calculated using the following equation: $$\mathrm{Hemolysis} \mathrm{rate} (\%)=\frac{({\mathrm{OD}}_{\mathrm{sample}} - {\mathrm{OD}}_{\mathrm{negative}})}{\left({\mathrm{OD}}_{\mathrm{positive}} - {\mathrm{OD}}_{\mathrm{negative}}\right)} \times 100$$
where OD_sample, OD_negative and OD_positive show the absorbance of 2% RBCs suspensions treated with all samples, NaCl solution (0.9%) and deionized water, respectively.

The adsorption capacities of BSNCs for MB were investigated in batch mode. The stock solution of MB was 1000 mg L⁻¹, which was prepared by dissolving 1 g of MB in 1 L deionized water. Different initial concentrations of MB were obtained through diluting the stock solution. The volume of MB solution was 50 mL and the given amount of the BSNCs was added to the MB solutions for each experiment. The conical flasks were fixed on a shaker with the speed of 200 rpm at 298 K. The remaining concentration of MB was determined at different time intervals of 10 min, 20 min, 30 min, 60 min, 120 min, 240 min and 360 min by UV-vis spectrometer (PerkinElmer, Waltham, MA, USA) at 665 nm. Three replicates of each experiment were performed.
The adsorbed amount of MB per unit mass of the adsorbent (q_e, mg g⁻¹) and the removal efficiency (R) of MB at equilibrium were calculated based on Equations (10) and (11).
$q_e = \frac{(C_0-C_e)V}{m}$
$Removal(\%)=\frac{C_0-C_e}{C_0} \times 100$
where C₀ and C_e are the initial and equilibrium concentrations of MB (mg L⁻¹), respectively. m is the mass of the adsorbent used (g), V is the volume of MB solution (L).