The BRICK is a compact, benchtop-ready single-molecule spectrometer for FCS or smFRET experiments. It’s designed to be simple and accessible; just unbox, plug in, and let it auto-calibrate. Unlike traditional setups, it does not require specialized rooms or complex infrastructure. With a small footprint (20 × 20 cm, 6 kg) and a single USB connection for power and data, it can be placed directly on a standard lab bench.

Fluorescence Correlation Spectroscopy (FCS) is a technique that measures fluctuations in fluorescence as molecules diffuse through a tiny detection volume. By analyzing these fluctuations, FCS provides information about molecular concentration, diffusion speed, size, and interactions.

It is conceptually similar to Dynamic Light Scattering (DLS), but instead of measuring bulk scattering from many particles at once, FCS detects single fluorescent molecules, offering much higher sensitivity and resolution.

Single-molecule Förster Resonance Energy Transfer (smFRET) is used to study structural changes and molecular interactions at the nanometer scale. By attaching two fluorescent dyes to specific sites on a biomolecule, smFRET acts as a molecular ruler: the efficiency of energy transfer between the dyes reveals how their distance changes.

This makes smFRET especially powerful for investigating conformational dynamics, folding pathways, binding events, and interactions that are difficult to resolve with bulk methods.

The BRICK is designed for simplicity. It performs auto-calibration on its own, so you don’t need any expertise in optics or physics. The included software also takes care of data processing and analysis, so you only need to extract the values that matter for your research.

For diffusion-based measurements, there is no strict “incorrect height” as long as the observation volume is inside the droplet of your sample. The BRICK uses an objective that automatically corrects for z-positioning, so minor variations don’t affect the measurement.

The only way positioning can go wrong is if the focus is outside the droplet. To prevent this, the BRICK includes a bright calibration sample used for auto-calibration. Its high fluorescence is hard to miss, so once you have found it, simply replace the calibration sample with your own sample and start measuring.

Not exactly. If you perform a smFRET measurement, you can also extract FCS information by autocorrelating the donor and acceptor fluorescence time traces. However, a standard FCS experiment cannot be used to generate smFRET data, since it lacks the specific donor–acceptor labeling required for energy transfer measurements. Additionally, the sample concentration in FCS may not be at the single-molecule level, so it doesn’t capture “one molecule at a time” events the way smFRET does.

Not exactly. While the BRICK uses a confocal detection volume similar to a microscope, it is a dedicated single-molecule spectrometer designed specifically for FCS and smFRET experiments. It does not provide imaging like a traditional microscope .

Its focus is on measuring molecular behavior and interactions at the single-molecule level.

Yes, long-term upgrades are planned. We are exploring the directions the BRICK could take, and user feedback will help guide future development. For now, our focus is on supporting FCS and smFRET, but additional features may be added over time.

For FCS, the only requirement is that your biomolecule produces a fluorescence signal. Proteins tagged with GFP are ready to use, or you can label them with an organic dye. Common labeling strategies include NHS chemistry to target lysines or maleimide chemistry to target cysteines. When labeling, it is important to ensure that the targeted amino acids do not participate in functional regions such as binding pockets, to avoid altering the protein’s behavior.

For smFRET, labeling is more specific and requires site-directed attachment of donor and acceptor dyes. This is usually achieved by introducing cysteine residues at defined positions via mutagenesis. When choosing labeling sites, consider the following criteria:

• Residues should be surface-exposed for accessibility.

• Mutations should not disrupt conserved or functionally critical regions.

• The donor–acceptor pair should provide a good dynamic range, meaning their distance changes noticeably between conformational states.

To simplify this process, the Cordes Lab developed theLabelizer, a tool that analyzes a protein’s structure (PDB file) and suggests optimal residues for smFRET labeling. By following these guidelines, you can ensure reliable measurements and meaningful single-molecule insights using the BRICK.

• For experts: The raw data can be converted into HDF5 files, a standard format compatible with academic analysis pipelines such as FRETbursts or PAM, allowing advanced users to perform custom analyses.

• For everyone else: FluoBrick Solutions provides its integrated, streamlined analysis software, which automatically processes the data and delivers results immediately, so you can focus on your research without needing specialized analysis skills.