Planar Photonic Crystal Biosensor for Quantitative Label-Free Cell Attachment Microscopy.

Area of Science:

• Biomedical Engineering
• Materials Science
• Cell Biology

Background:

• Cell-surface interactions are crucial for understanding cellular processes.
• Existing biosensors can introduce artifacts due to substrate topography.
• Label-free imaging techniques are needed to observe cellular behavior without external modulation.

Purpose of the Study:

• To demonstrate a planar-surface photonic crystal (PC) biosensor for quantitative, kinetic, label-free imaging of cell-surface interactions.
• To create a biosensor surface that minimizes external stimuli to cells, mimicking in vitro smooth environments.
• To compare cellular responses on planar versus structured surfaces.

Main Methods:

• Fabrication of a planar PC biosensor using nanoreplica molding and horizontal dipping.
• Utilizing the PC biosensor for label-free imaging of live cell-substrate interactions.
• Comparing cell morphology and attachment behavior on planar and grating-structured PC biosensors.

Main Results:

• The planar PC biosensor achieved high detection sensitivity for monitoring live cell-substrate interactions.
• Spatial resolution was sufficient to observe intracellular attachment strength gradients and filopodia extension.
• Planar surfaces eliminated directionally biased cellular attachment observed on grating-structured surfaces.

Conclusions:

• The planar PC biosensor accurately reflects smooth surface environments, reducing artifacts.
• This technology enables label-free observation of cellular processes with high spatial resolution.
• The development advances label-free techniques for studying cellular behavior without unintended environmental modulation.