Biomolecular uptake effects on chitosan/tripolyphosphate micro- and nanoparticle stability

Area of Science:

• Biomaterials Science
• Nanotechnology
• Drug Delivery Systems

Background:

• Colloidal chitosan/tripolyphosphate (TPP) particles are investigated as delivery vehicles for drugs, genes, and vaccines.
• Previous studies indicate these particles may disintegrate at physiological pH and ionic strength.
• A hypothesis suggests that bioactive payloads might stabilize chitosan/TPP particles.

Purpose of the Study:

• To investigate if association with model anionic proteins (α-lactalbumin, BSA) and DNA enhances chitosan/TPP particle stability.
• To evaluate particle stability in physiological ionic strength conditions (150 mM NaCl, pH 5.5 and 1× PBS, pH 6.0).

Main Methods:

• Utilized light scattering and UV-vis spectroscopy to assess particle stability.
• Examined the effect of incorporating anionic proteins and DNA on chitosan/TPP particle dissolution.
• Investigated payload association during and after particle formation.

Main Results:

• Anionic protein association did not significantly impact chitosan/TPP particle stability due to weak binding and rapid release.
• DNA incorporation, in certain compositions, increased the persistence of complexed chitosan fractions.
• DNA remained largely complexed with chitosan under all tested conditions.

Conclusions:

• Most bioactive payloads do not bind strongly enough to stabilize chitosan/TPP particles against dissolution.
• Polyanions, such as DNA, can enhance the stability of chitosan/TPP particles in physiological media.
• This finding has implications for optimizing chitosan-based delivery systems.