Spray dried hydroxyapatite-based supraparticles with uniform and controllable size and morphology

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Hydroxyapatite (HAP) based materials are crucial in biomedical applications.
• Controlling the morphology of HAP supraparticles is essential for tailored properties.
• Spray drying offers a scalable method for supraparticle fabrication.

Purpose of the Study:

• To achieve uniform hydroxyapatite-based (HAP) supraparticles with controllable morphology.
• To investigate the influence of precursor suspension properties on supraparticle formation.
• To establish a relationship between processing parameters and final supraparticle shape.

Main Methods:

• Utilized microfluidic spray drying for HAP supraparticle preparation.
• Employed sodium polyacrylate (PAAS) to regulate inter-particle repulsive forces.
• Used sodium chloride (NaCl) to control electrostatic shielding effects in precursor suspensions.

Main Results:

• Supraparticle morphology was directly linked to suspension particle size (D50) and zeta potential.
• Low D50 (< 2 µm) and high absolute zeta potential (> 20 mV) resulted in deformed supraparticles due to ultralow shell permeability (k).
• High D50 (> 2 µm) and low absolute zeta potential (< 20 mV) yielded spherical supraparticles via high shell permeability (k).

Conclusions:

• Microfluidic spray drying parameters, specifically HAP to PAAS mass ratio (mH/mP) and NaCl concentration (CNacl), effectively control HAP supraparticle morphology.
• Suspension properties (D50, zeta potential) act as key mediators between processing conditions and final supraparticle shape.
• This method provides a pathway for fabricating HAP-based supraparticles with tunable characteristics for various applications.