Measuring local properties inside a cell-mimicking structure using rotating optical tweezers.

Area of Science:

• Biophysics
• Cellular Mechanics
• Nanotechnology

Background:

• Investigating intracellular material rheology is crucial for understanding cellular and subcellular processes.
• Optical traps are valuable tools for manipulating micro/nano objects in biological fluid studies.
• Challenges exist in understanding probe particle mobility near cellular membranes and organelles.

Purpose of the Study:

• To investigate the rheological properties of intracellular materials using a biomimetic model.
• To theoretically and experimentally study the mechanical properties within a liposome using optical tweezers.
• To predict hydrodynamic interactions between membranes and internal probe particles at submicron distances.

Main Methods:

• Utilized liposomes (unilamellar lipid vesicles) as a biomimetic model for living cells.
• Employed optical tweezers to trap and rotate a probe particle within the liposome.
• Combined theoretical and experimental approaches to analyze rheological properties.

Main Results:

• Demonstrated the system's capability to predict hydrodynamic interactions between 3D membranes and internal probe particles.
• Quantified the influence of membrane proximity on probe particle mobility within submicron distances.
• Established a method for studying rheology in confined cellular environments.

Conclusions:

• The developed system accurately models hydrodynamic interactions in confined cellular environments.
• This approach has potential for designing high-resolution optical micro/nanorheology techniques for in vivo applications.
• Understanding these interactions is key to advancing studies of cellular mechanics and dynamics.