Optima 7000dv

Prior to analysis, solid sponge sample was dissolved in concentrated nitric acid, then adjusted to 14% v/v concentration of nitric acid using Milli-Q H₂O before undergoing microwave digestion and passing through a 0.4 µm syringe filter. Cadmium and zinc standards were prepared by diluting stock standard solutions to levels in the linear range for the instrument using the same acidified Milli-Q water used in the preparation of the sponge digestate. Inductively coupled plasma optical emission spectrometry (ICP-OES) analyses were performed on the Perkin-Elmer OPTIMA 7000 DV Inductively Coupled Plasma-Optical Emission Spectrometer equipped with an axial torch, cyclonic spray chamber, and Meinhard^® Type C concentric nebuliser. The operating conditions were RF Power 1300 W, plasma flow 15 L/min, auxiliary flow 0.2 L/min, nebuliser flow 0.8 L/min and a viewing distance of 15.0 mm. Each element was initially analysed by three spectral lines and then a single spectral line that exhibited low interference and high analytical signal and background ratios were selected for each element. These spectral lines were 228.804 nm (Cd) and 213.860 (Zn). Each element was quantified by the average of two readings.

The assessment of in vitro bioactivity of the five types of scaffolds was carried out in simulated body fluids (SBF) solution. The SBF solution has a composition and ionic concentration similar to that of human plasma. Each scaffold was soaked in 10 mL of SBF solution in a polyethylene bottle at 37°C for 1, 3, 7, and 14 days. SBF solution was refreshed every other day. Then the scaffolds were collected, washed gently with distilled water, and dried at 60°C. The sizes of all scaffolds were around Ø6 × 6 mm as they were prepared. SEM and electron dispersive spectrometer (EDS) (INCA Energy, Oxford Instruments, UK) were used to examine the mineralized apatite on the surface of the scaffolds. The ion concentration (Ca, P, and Si) of the solution taken after soaking was tested by ICP-AES (Perkin-Elmer Optima 7000DV).

Before NO and Cu ions release experiment, the NMPGA was numbered and cut into a square with an average area of 2 × 2 cm², and the weight was recorded. Similarly, the NMHK was also numbered and weighted by a certain mass. After that, the as-prepared samples (NMHK and NMPGA) were immersed into 30 mL PBS solution (pH = 7.4) at 37 °C in a shaker with a rotating speed of 80 rpm for 2 w. At each defined time point, 4 mL of the release medium was taken out for detection, and an equal volume of the fresh PBS solution was added. Then, the ultraviolet spectrophotometer (UV-300, Thermo Spectronic, USA) was used to evaluate the amount of NO released from the medium with Griess reagent at 520 nm absorption peak (n = 3) [15 (link), 25 (link)]. The concentrations of Cu ions released from the NMHK and NMPGA were determined by inductive coupled plasma atomic emission spectrometry (ICP-AES, Optima 7000 DV, Perkin-Elmer, USA) (n = 3).

Membranes with a diameter of 10 mm were immersed in 500 mL deionized water at 37°C for 1, 4, 7, 10, 13, 16, 19, and 22 days to measure the release of Ag and Mg ions from GT/PCL-Ag-Mg. The deionized water was refreshed at each time point. The concentrations of Ag and Mg in the collected deionized water were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES, PerkinElmer Optima 7000 DV).

The amount of silver released from the electrospun mats over time was monitored via inductively coupled plasma optical emission spectroscopy (ICP-OES) with a PerkinElmer Optima 7000 DV apparatus (PerkinElmer, Waltham, MA, USA). Three specimens per sample of approximately 15 mg were cut from the mats, placed into a centrifugation tube with 10 mL of phosphate-buffered saline (PBS) and then incubated at 37 °C under oscillation for up to 800 h. At different time intervals, the solutions were extracted and digested overnight with nitric acid at a 1:1 ratio by volume. Calibration was conducted using an external standard between 0.5 and 25 ppm.

The PEFS was characterized -in our previous work [37 (link)]. The inorganic elements in PEFS were investigated with the help of the inductively coupled plasma optical emission spectrometer (Perkin Elmer, model Optima 7000 DV, Waltham, MA, USA). An elemental analyser (Vario, Micro CHNS Analyser, Hesse, Germany) was used to study the weight percentages of carbon, hydrogen, nitrogen and sulfur in PEFS. The surface groups on PEFS were predicted with the help of Fourier transform infrared spectroscopy (FT-IR) by using the Perkin Elmer model Paragon 1000 PC spectrophotometer, Waltham, MA, USA. X-ray diffraction (XRD) patterns for PEFS were studied with an X-ray diffractometer Rigaku Smart Lab diffractometer, Tokyo, Japan. The surface morphology of PEFS was determined by field emission scanning electron microscopy (FE-SEM, Tescan Mira 3, Brno, Czech Republic).