Plug-and-play polymer microfluidic chips for hydrated, room temperature, fixed-target serial crystallography

Area of Science:

• Structural Biology
• Biophysics
• Crystallography

Background:

• Serial X-ray crystallography (SX) requires efficient hydrated protein crystal delivery and minimized background scattering.
• Fixed-target devices offer advantages over jet injectors, including lower sample consumption and clog-free operation.
• Optimizing crystal density on-chip is crucial for improving hit rates in SX experiments.

Purpose of the Study:

• To develop versatile, inexpensive, and robust polymer microfluidic chips for routine room-temperature SX.
• To enable reliable serial X-ray measurements at synchrotrons and X-ray free electron lasers (XFELs).
• To provide a user-friendly platform for diffraction measurements with adaptable sample and beamline requirements.

Main Methods:

• Fabrication of polymer microfluidic chips with X-ray-transparent thin film layers to reduce scatter.
• Adaptable sample flow layers designed to match crystal size for optimal delivery.
• Benchmarking using serial oscillation crystallography at a microfocus synchrotron beamline (SSRL).

Main Results:

• High-resolution structures (1.3–2.7 Å) were determined for five different proteins.
• Chips demonstrated clog-free delivery, low sample consumption, and stability for extended periods.
• Modular fabrication allowed precise control over the X-ray beam path and chip adaptability.

Conclusions:

• The developed polymer microfluidic chips offer a robust and versatile solution for room-temperature serial X-ray crystallography.
• These chips facilitate user-friendly, straightforward diffraction measurements at various X-ray sources.
• The design enhances hit rates and sample utilization, advancing structural biology studies.