Depth-multiplexed ptychographic microscopy for high-throughput imaging of stacked bio-specimens on a chip

Area of Science:

• Biomedical imaging
• Microscopy
• Optical sensing

Background:

• High-speed imaging of numerous bio-specimens is crucial for biomedical applications.
• Conventional methods involve sequential imaging of laterally positioned specimens, limiting throughput.
• There is a need for parallel imaging strategies to enhance efficiency.

Purpose of the Study:

• To introduce a novel on-chip imaging strategy, depth-multiplexed ptychographic microscopy (DPM), for high-speed parallel imaging and sensing.
• To demonstrate the capability of DPM for time-lapse cell culture monitoring and high-throughput cytometric analysis.
• To highlight DPM's advantages in data multiplexing and its compatibility with microfluidic devices.

Main Methods:

• Developed a DPM system by stacking multiple specimens axially and imaging them simultaneously.
• Modified a low-cost car mirror for programmable laser beam steering.
• Utilized a blood-coated image sensor for acquiring diffraction patterns and performed blind recovery for object reconstruction.

Main Results:

• Demonstrated time-lapse monitoring of 3 stacked microfluidic cell culture channels.
• Achieved high-throughput cytometric analysis of 5 stacked brain sections (205 mm² FOV) in approximately 50 seconds.
• Quantified cellular proliferation biomarkers on brain sections.

Conclusions:

• DPM enables parallel imaging of multiple specimens using a single detector, adding a new dimension to microscopy data multiplexing.
• The system achieved a 6-mm depth of field, one of the longest in microscopy.
• DPM offers an efficient on-chip sensing and imaging solution, complementing microfluidics for streamlined sample handling.