The physicochemical interactive mechanism between nanoparticles and raffinose during freeze-drying

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Maintaining nanoparticle size during drying is crucial for applications.
• Limited research exists on preserving nanoparticle dimensions through drying processes.

Purpose of the Study:

• To investigate the interaction mechanism between raffinose and nanoparticles during freeze-drying.
• To evaluate the effect of freeze-drying on nanoparticle size stability.

Main Methods:

• Comparative analysis of freeze-dried and normally dried nanoparticle-raffinose mixtures.
• Particle size measurement before and after drying.
• Powder X-ray diffraction (PXRD) analysis.
• Differential scanning calorimetry (DSC) to detect thermal events.

Main Results:

• Freeze-dried nanoparticles with raffinose maintained their size (170.5 nm rehydrated vs. 156.1 nm initial).
• PXRD showed a halo pattern for freeze-dried samples, indicating amorphous structure, versus crystalline for normal-dried.
• DSC revealed no endothermic peak for freeze-dried raffinose, unlike normal-dried samples.

Conclusions:

• Raffinose acts as a cryoprotectant, preserving nanoparticle size during freeze-drying.
• The drying method significantly influences the interaction and structural outcome between nanoparticles and raffinose.
• Immobilization in ice during freeze-drying prevents molecular rearrangement and aggregation.