8400s spectrophotometer

Fourier transform infrared spectra were taken using an 8400S spectrophotometer (Shimadzu, Tokyo, Japan). KBr pellets were used, and the spectra were recorded in aqueous medium.
The morphology of the Fe₃O₄-HAp nanostructures was observed using a scanning electron microscope (ICON, Quanta 200 Mark II Environmental scanning electron microscope) with an acceleration voltage of 0.2–30 kV.
The thermal properties of the prepared nanocomposites were investigated using a thermal analyzer (STA 449 F3 Jupiter, Netzsch Gerätebau GmbH, Selb, Germany) along with thermogravimetry and differential scanning calorimetry in the temperature range of 28°C–1,100°C at a heating rate of 20°C per minute in a dry air atmosphere. Al₂O₃ was used as the reference material.
Diffuse reflectance spectroscopy was performed using a Specord 210 Plus (Analytik Jena, The Woodlands, TX, USA) between 190 and 1,100 nm at room temperature.
The superparamagnetic properties of the Fe₃O₄-HAp nanocomposites were studied using a 7410 vibrating sample magnetometer (Lake Shore, Westerville, OH, USA), in atmospheric air at room temperature.
The cytotoxic effects of the Fe₃O₄-HAp nanocomposites were evaluated using MG63 cells. The MTT assay was performed according to the procedure shown in Figure 2. The formazan was dissolved in dimethyl sulfoxide and the absorbance of the solution was quantified at 510 nm.

The formation Ag NPs capped with different concentrations of lipase was followed using UV-visible spectrophotometer (Shimadzu UV-3600 plus). Energy dispersive X-ray fluorescence (ED-XRF) studies were performed using Epsilon-1 Analytical instrument to ascertain the chemical identity of silver. Fourier Transform infrared (FT-IR) analyses of the synthesized Ag NPs were performed using Shimadzu 8400S spectrophotometer to confirm the lipase capping. Malvern Zeta Sizer Nano instrument was used to characterize the lipase capped Ag NPs to determine the hydrodynamic diameter. The morphological characteristics were analyzed using high-resolution transmission electron microscopy (HR-TEM, FEI, Tecnai G2, F30). For this, ∼10 μL of the lipase capped Ag NPs solution was dropped over the TEM grids and dried in a vacuum desiccator for overnight.

¹H NMR spectra were measured at 298 K on a Bruker Ultrashield Plus 400 MHz spectrometer. C, H, and N analyses were performed with a CHN–S Flash E1112 Thermo Finnigan analyzer. FT-IR spectra were obtained on KBr pellets and collected with a Shimadzu-8400S spectrophotometer. Electrospray Ionization Mass Spectrometry (ESI-MS) data were acquired on HPLC grade methanol by using a Thermo Scientific LCQ-Fleet mass spectrometer under electrospray ionization (Thermo Scientific, Austin TX, USA) by direct infusion with a 500 KL Hamilton microsyringe. Data were acquired over hundred scans after the stabilization of the ionic current for 5 min at a sample flow of 10 μl min^–1. The mass spectrometer parameters used were: sheet gas flow = 10, auxiliary gas flow = 0, sweep gas flow = 0, spray voltage = 5.00 kV, capillary tube temperature = 220 °C, and capillary voltage = 12.0 V.