New study on temperature change induced structure recovery patterns could help drug delivery

Key Highlights:

• Scientists from the Raman Research Institute (RRI), an autonomous institute under the Department of Science and Technology (DST), discovered a method to induce momentary flow in jammed systems.
• This method involves applying sudden temperature shocks, which effectively erases "memory imprints" and controls "asymmetries" in these materials.
• The research utilized microgels, squishy particles capable of absorbing 300-500 times their weight in water.
• This breakthrough has significant implications for targeted drug delivery, where temperature-responsive materials are crucial.

Detailed Insights:

• Materials like glass exhibit solid-like mechanical properties but liquid-like structural characteristics and retain memory imprints.
• Researchers aimed to momentarily convert these glass-like systems to a liquid state to control their structure and erase memory.
• The experiment involved jam-packing microgel particles, which are thermo-responsive and used in products like diapers and sanitary napkins.
• They observed an "asymmetry" in the path the microgel suspension took during heating and cooling processes.
• Applying a sudden temperature ramp rate (thermal shock) caused particles to rearrange, leading to a temporary liquid state.
• This rearrangement obliterates the observed asymmetries and erases the system's memory of previous thermal paths.
• In drug delivery, microgels can be loaded with drugs when cool and then collapse above 34°C (below body temperature) to release medicine at targeted sites.
• Understanding how thermal shocks influence the structural recovery of these materials is vital for enhancing their utility in such applications.

Scientific/Technical Concepts Involved:

• Jammed Systems: Materials that behave mechanically like solids but have a disordered, liquid-like internal structure.
• Microgels: Soft, deformable polymer particles that can swell significantly in water and are sensitive to temperature changes.
• Structural Recovery: The process by which a system attempts to flow and reach its minimum energy configuration.
• Memory Imprints: Retained structural characteristics or past states within a material that influence its current behavior.