Dsc 4000 analyzer

To investigate the information about the phase transition behaviors of retinol-loaded lipid nanoparticles, such as denaturation and melting, DSC analysis was performed with the Perkin-Elmer DSC 4000 analyzer (Perkin Elmer, Wellesley, MA, USA). Approximately 10 mg of the sample were loaded on the closed-type aluminum sample pan and heated from 30 to 80 °C at a scan rate of 10 °C/min. The same empty pan was used as a reference. The temperatures of the melted peaks and enthalpies of the tested samples were calculated by the Pyris manager software, data analysis program supplied by Perkin-Elmer (Perkin Elmer, Wellesley, MA, USA).

The FTIR spectra of Li-MA and K-MA were obtained using an optics spectrometer (FT/IR-6700, JASCO, Osaka, Japan) in the frequency range 4000–400 cm⁻¹. Differential scanning calorimetry (DSC, PerkinElmer DSC-4000 analyzer, Akron, OH, USA) was used to measure the thermal behavior of MA, Li-MA, and K-MA under N₂ gas (flow rate: 50 mL min⁻¹) at a heating rate of 0.5 °C min⁻¹ in the temperature range from 30 to 400 °C. X-ray diffraction (XRD) was performed using a D₂ PHASER (Bruker, Karlsruhe, Germany) with Cu Kα radiation (λ = 1.5406 Å) at an energy of 8.04 keV with a uniform increment size (2θ) of 5° at a scan rate of 5° min⁻¹. The morphology of the electrodes was observed through field-emission gun scanning electron microscopy (SEM; JEOL JSM-6500, JEOL. Ltd., Tokyo, Japan) performed at an accelerating voltage of 15 keV.