Label-free Protein Analysis
Label-free Protein Analysis - Related Videos
12:19
ReAsH/FlAsH Labeling and Image Analysis of Tetracysteine Sensor Proteins in Cells
0 Views •
Cited by 10 •
2011
The biarsenical dyes FlAsH and ReAsH bind specifically to tetracysteine motifs in proteins and can selectively label proteins in live cells. Recently this labeling strategy has been used to develop sensors for different protein conformations or oligomeric states. We describe the labeling approach and methods to quantitatively analyze binding.
08:36
AirID-Based Proximity Labeling for Protein-Protein Interaction in Plants
0 Views •
Cited by 2 •
2022
Here, we present a step-by-step protocol for performing the proximity labeling (PL) experiment in cucumber (Cucumis sativus L.) using AT4G18020 (APRR2)-AirID protein as a model. The method describes the construction of a vector, the transformation of a construct through agroinfiltration, biotin infiltration, protein extraction, and purification of biotin-labeled proteins through affinity purification technique.
06:48
Antibody Labeling with Fluorescent Dyes Using Magnetic Protein A and Protein G Beads
0 Views •
Cited by 3 •
2016
The on-bead method for labeling antibodies with small molecules enables labeling of a small amount of antibodies directly from cell media. This method is compatible with amine and thiol chemistry, and can handle multiple samples in parallel, manually or using automated platforms.
09:38
Fluorescence Labeling to Visualize Low-Expressed Proteins in Zebrafish
0 Views •
2025
Here, we present a protocol to label proteins with a fluorescence protein tag in zebrafish larvae, a newly developed and modified in vivo system especially useful for visualizing low-abundance proteins in zebrafish.
09:19
Simultaneous Label-Free Autofluorescence Multi-Harmonic Microscopy
0 Views •
Cited by 6 •
2025
This protocol presents a step-by-step guide for the Simultaneous Label-free Autofluorescence Multi-harmonic (SLAM) microscopic technique, including details on how to generate the laser light source, prepare a tissue sample, conduct imaging, and analyze the data. SLAM advances nonlinear microscopy by measuring four complementary label-free contrasts to investigate the tissue microenvironment.
FAQs
The selected signal determines which protein property the assay can monitor. Mass provides molecular information, while size and charge help distinguish physical characteristics. Refractive-index changes and sensor-surface responses can indicate protein accumulation or binding. Matching the detection principle to the question helps engineers evaluate concentration, interactions, stability, or binding behavior.
Maintaining native properties helps measurements reflect the protein's behavior in its unmodified state. Added fluorescent, radioactive, or enzymatic tags can increase assay complexity and may introduce labeling artifacts. Label-free measurements therefore support more direct evaluation of protein interactions and stability, which is important when designing formulations, bioprocesses, or biomaterials.
When proteins bind to a sensor surface, the interaction can produce a measurable change at that surface. Tracking the response over time provides information about whether binding occurs and how the interaction progresses. This makes optical sensing and biosensor platforms useful for studying binding kinetics and comparing interaction behavior under engineered assay conditions.
A practical workflow begins by selecting a platform whose intrinsic signal matches the measurement goal, such as mass, refractive index, or a surface response. The protein is then assessed through the instrument or sensor, and the resulting signal is interpreted for concentration, stability, binding kinetics, or interactions. The chosen readout guides subsequent engineering decisions.
Engineering researchers can apply these methods when developing or evaluating bioprocesses, therapeutic formulations, biomaterials, and diagnostic devices. The measurements help determine whether proteins remain stable, reach the intended concentration, or interact as designed. Because the approach can provide real-time information, it also supports monitoring during development rather than relying only on a final endpoint.
Tagged assays attach a fluorescent, radioactive, or enzymatic marker, whereas label-free approaches measure properties already associated with the protein or its interaction environment. Avoiding a tag can reduce assay complexity and limit labeling artifacts while preserving native interactions. This comparison is especially relevant when engineers need measurements that reflect protein behavior without modifying the analyte.