X-ray driven and intrinsic dynamics in protein gels

Area of Science:

• Soft Matter Physics
• Biophysical Chemistry
• Materials Science

Background:

• Egg white protein gels exhibit complex viscoelastic properties.
• Understanding X-ray radiation effects on biological gels is crucial for various applications.

Purpose of the Study:

• Investigate the impact of X-ray dose and dose rate on the structure and dynamics of egg white protein gels.
• Determine the sensitivity of gels with varying viscoelastic properties to X-ray induced effects.
• Characterize the transition from equilibrium dynamics to beam-induced motion.

Main Methods:

• X-ray Photon Correlation Spectroscopy (XPCS) was employed.
• Analysis of structural changes and dynamics under varying X-ray conditions.
• Determination of X-ray fluence thresholds for beam-induced motion.

Main Results:

• Soft gels are more susceptible to X-ray induced fluidization and dynamical changes than high-temperature gels.
• A crossover from stress relaxation to heterogeneous dynamics was observed in soft gels at low X-ray doses (few kGy).
• X-ray fluence thresholds for beam-induced motion were determined, significantly lower for soft gels.

Conclusions:

• Viscoelastic properties govern the response of protein gels to X-ray radiation.
• Beam-induced motion in soft viscoelastic materials occurs at low fluences and is distinct from static damage.
• XPCS can differentiate intrinsic sample dynamics from X-ray driven motion.