A novel microfluidic chip for on-site radiation risk evaluation

Area of Science:

• Biomedical Engineering
• Radiation Biology
• Microfluidics

Background:

• Conventional DNA double-strand break (DSB) assays require extensive laboratory space and complex procedures.
• On-site biological effect evaluation of radiation exposure is crucial for rapid risk assessment.

Purpose of the Study:

• To develop a microfluidic chip for on-site radiation risk evaluation.
• To simplify the DNA double-strand break (DSB) assay using immunofluorescence staining for phosphorylated histone, H2AX (γ-H2AX).

Main Methods:

• A microfluidic chip was designed to separate and trap lymphocytes from whole blood using size-based separation and a unique trap structure.
• The γ-H2AX assay was performed directly on the chip.
• Bead experiments and cell-based assays using human lymphoblastoid TK6 cells were conducted to validate the chip's performance.

Main Results:

• The chip successfully separated beads of different sizes (10 μm and 27 μm) using centrifugal force and passive structures.
• Over 95% of 10 μm beads were trapped in the lymphocyte trap structures (LTSs).
• TK6 cells were effectively trapped, and γ-H2AX foci, indicating DSBs, were observed on the chip.

Conclusions:

• The proposed microfluidic chip simplifies the γ-H2AX assay protocol.
• This novel method enables on-site biological effect evaluation of radiation exposure, overcoming the limitations of conventional laboratory-based assays.