Model dsc7

The thermal stability test on parrotfish scales was carried out with a Perkin-Elmer differential scanning calorimeter (Model DSC7, Norwalk, CA, USA) under a nitrogen atmosphere. The procedure used in this work was pointed from the study of Kittiphattanabawon et al. [31 (link)]. Freeze-dried collagens were prepared for rehydration at a ratio of 1 : 40 (w/v) with distilled water and then incubated for two days in a refrigerator. Afterwards, the prepared samples were accurately weighed (ranging from 5 mg to 10 mg) into an aluminum volatile pan and then tightly sealed with a crimper. Prior to running the samples, a calibration step was performed with an indium. Subsequently, a sealed collagen sample and an empty pan were placed into sample and reference detectors, respectively, and then scanned from 20°C to 45°C at a rate of 1°C per minute. DSC rates were expressed in the maximum transition temperature (T_max) and the total denaturation enthalpy (ΔH).

The thermostability of PSSC, PSBC and PSCC was analyzed using a DSC apparatus (Perkin-Elmer, Model DSC7, Norwalk, CA, USA) based on the procedure by Kittiphattanabawon et al. [37 (link)]. Lyophilized collagens were rehydrated at a ratio of 1:40 (w/v) with de-ionized water. Rehydrates were then placed in a chiller for two days. Subsequently, the rehydrated fish collagens were weighed (between 5 mg and 10 mg) into an aluminum pan (Perkin-Elmer, Norwalk, CA, USA) and then tightly sealed. Before running the samples, the DSC machine was calibrated using indium as a standard. Furthermore, the sealed samples were scanned between 20 °C and 50 °C at a rate of 1 °C per minute. An empty pan was applied as a baseline. The maximum transition temperature (T_max) was recorded from the thermogram’s endothermic peak, whilst the total denaturation enthalpy (ΔH) was obtained from the thermogram’s area.

A DSC machine (Perkin-Elmer, Model DSC7, Norwalk, CA, USA) was used to obtain the thermostability value of the extracted collagens from the unicornfish bones. First, the prepared samples were hydrated by adding deionized water at a ratio of 1:40 (w/v) for 48 h in a chiller. The hydrates were then weighed from 5 mg to 10 mg into an aluminum pan (Perkin-Elmer, Norwalk, CA, USA), and tightly sealed. The DSC instrument was previously calibrated using an indium as a standard, and the sealed samples were subsequently scanned, ranging from 20 °C to 50 °C at a rate of 1 °C per minute. An empty pan was used as a reference. Thermostability in all samples was determined using the maximum transition temperature (T_max), which was collected from the endothermic peak of thermogram, and the total denaturation enthalpy (ΔH) was recorded from the area of thermogram [59 (link)].

DSC of acid-extracted skin collagens was conducted following the procedure described by Kittiphattanabawon et al. [59 (link)]. The freeze-dried samples were rehydrated with deionized water at a solid/solution ratio of 1:40. The rehydrated samples were then allowed to stand for 2 days in a chiller (4 °C) and weighed accurately into aluminum pans (6–12 mg) and sealed tightly. Before scanning, DSC instrument (Perkin-Elmer, Model DSC7, Norwalk, CA, USA) was calibrated using indium as a standard. Then, the sealed samples were scanned between the range of 20 °C and 50 °C with heating rate at 1 °C/min. An empty pan was prepared for the reference. The maximum transition temperature (T_max) was detected from the endothermic peak of thermogram. Total denaturation enthalpy (ΔH) was recorded by measuring the area of the DSC thermogram.

Differential scanning calorimeter (Perkin Elmer, Model DSC7, Norwalk, CA, USA) was used. Accurately weighed samples were loaded onto aluminum pans and sealed. Temperature scanning was performed at 10 °C/min over the range of −40 to 250 °C.

DSC thermograms were generated using a Model DSC 7 (Perkin Elmer^®, Norwalk, CT, USA), fitted with a PC control unit TAC 7 (Perkin Elmer^®, Norwalk, CT, USA) at a heating rate of 10 °C/min and a nitrogen flow rate of 20 mL/min. Approximately 3.0 mg of individual samples and 1:1 mixtures of the drugs and polymers to be tested for compatibility, were weighed directly into aluminum DSC pans and hermetically sealed prior heating at a constant rate using an empty pan as the reference. The samples were placed directly onto a micro hot stage DSC and thermograms were generated at temperatures between 30 and 440 °C. The DSC cell was calibrated for temperature and enthalpy with indium (mp. 156.6 °C; ΔH_fus = 28.4 j/g) and the resultant data were analyzed using Pyris^TM Manager Software (Perkin Elmer^®, Norwalk, CT, USA).