The dielectric study of insulin-loaded reverse hexagonal (H(II)) liquid crystals

Area of Science:

• Materials Science
• Physical Chemistry
• Biophysics

Background:

• The hexagonal II (HII) mesophase, formed by GMO-TAG-water systems, is a promising carrier for drug delivery.
• Understanding its dielectric behavior is crucial for controlling drug release kinetics.

Purpose of the Study:

• To investigate the dielectric properties of an insulin-loaded HII mesophase.
• To elucidate the structural and dynamic changes induced by glycerol and insulin.
• To correlate these changes with controlled release mechanisms.

Main Methods:

• Dielectric spectroscopy was employed across a frequency range of 10(-2)-10(6) Hz and a temperature range of 290-333 K.
• Reference systems (empty HII mesophases) were used for comparison.
• Analysis focused on identifying relaxation processes and critical temperature points.

Main Results:

• Three distinct relaxation processes were observed, attributed to GMO polar heads, counterion movement, and TAG dynamics.
• Glycerol addition created a heterogeneous core-structure within HII cylinders.
• Heating revealed dehydration and energetic modification points, enabling controlled release.
• Insulin incorporation altered the GMO-water interface and reduced GMO headgroup mobility.

Conclusions:

• Insulin loading in the HII mesophase modifies its dielectric behavior and dynamics.
• The observed structural changes and relaxation processes are key to understanding and optimizing insulin delivery.
• The HII mesophase demonstrates potential for on-demand, controlled release applications.