Structural, Compositional, and Dielectric State Profiling in Label-Free Single-Cell Monitoring

Area of Science:

• Biophysics
• Cell Biology
• Analytical Chemistry

Background:

• Cellular functional states are crucial for drug response, disease, and manufacturing.
• Label-based measurements face limitations like photobleaching and phototoxicity.
• Label-free monitoring using intrinsic physical signals offers a promising alternative.

Purpose of the Study:

• To review and organize label-free single-cell monitoring modalities.
• To establish a physics-grounded framework linking intrinsic signals to cellular phenotypes.
• To evaluate current platforms and identify future requirements for scalable phenotyping.

Main Methods:

• Categorization of label-free monitoring into imaging-based, vibrational spectroscopy-based, and electrical sensing-based modalities.
• Analysis of measurement principles, drift sources, and feature spaces for each modality.
• Evaluation of representative platforms based on design, feature definition, performance, and validation.

Main Results:

• Each modality is linked to distinct intrinsic state variables (structural, molecular, dielectric).
• Dominant analytical constraints vary across modalities, suggesting integrative approaches.
• Shared requirements for calibration, standardization, and multimodal integration are identified.

Conclusions:

• Integrative architectures combining complementary modalities can resolve ambiguities.
• Future advancements require hardware miniaturization, edge inference, and AI for molecular attribution.
• Scalable quantitative single-cell phenotyping can be achieved through these advancements.