Valency driven modulation of SDS-insulin complexation: A physicochemical study with biorelevant electrolytes

Area of Science:

• Biochemistry
• Physical Chemistry
• Materials Science

Background:

• Electrolytes play active roles in biological systems, influencing molecular interactions.
• Understanding electrolyte effects is vital for optimizing drug delivery and protein stability.

Purpose of the Study:

• To investigate how cation valency affects the complexation of sodium dodecyl sulphate (SDS) with insulin.
• To elucidate the impact of physiologically relevant cations (Na+, K+, Zn2+, Co2+) on micellization and protein-surfactant binding.

Main Methods:

• Conductometric measurements to analyze specific conductance and ion sequestration.
• Tensiometric measurements to determine critical micelle concentration (CMC) and interfacial parameters.
• UV-Visible spectroscopy to study complex formation and binding interactions.

Main Results:

• Divalent cations (Zn2+, Co2+) significantly enhance SDS micellization and SDS-insulin binding compared to monovalent ions.
• Electrolyte addition reduced CMC and altered surface tension, indicating improved molecular packing.
• Thermodynamic analysis confirmed spontaneous binding and partitioning, with Zn2+ and Co2+ showing stronger stabilization.

Conclusions:

• Cation valency critically influences electrolyte-surfactant-protein interactions, affecting micelle formation and stability.
• Findings provide mechanistic insights for designing electrolyte-tuned biotherapeutic systems.
• Enhanced protein-surfactant complexation suggests improved performance and stability for biotherapeutics.