Photophysical Characterization Service

We first review the probe structure, intended application, and detection platform to define the appropriate characterization plan.

• Review the probe type, such as mitochondrial membrane potential probe, ROS/redox probe, ion probe, pH probe, metabolic probe, mitophagy probe, fusion/fission probe, MitoTimer-related reporter, or custom fluorescent dye.
• Confirm the intended detection platform, such as fluorescence microscopy, confocal imaging, two-photon imaging, plate reader, flow cytometry, high-content imaging, or NIR imaging.
• Clarify the intended readout format, such as turn-on fluorescence, ratiometric fluorescence, dual-channel emission, red/green ratio, NIR activation, fluorescence lifetime, or intensity-based detection.
• Define expected application conditions, including aqueous buffer, cell culture medium, serum-containing medium, organic cosolvent, pH range, temperature, and probe working concentration.
• Identify key risks, such as weak fluorescence, spectral overlap, aggregation, photobleaching, pH interference, poor aqueous compatibility, or high background signal.

We measure the basic optical profile of the probe to define its excitation and detection windows.

• Record UV–Vis absorption spectra under selected solvent or buffer conditions.
• Measure fluorescence emission spectra at optimized excitation wavelengths.
• Determine excitation maximum, emission maximum, Stokes shift, and spectral bandwidth.
• Compare spectral profiles across different solvents, buffers, pH conditions, or biological media.
• Evaluate spectral compatibility with standard filter sets, confocal laser lines, flow cytometry channels, and plate-reader optics.
• Identify potential overlap with other probes used in multicolor mitochondrial imaging.

We evaluate whether the probe produces sufficient fluorescence intensity for the intended assay.

• Estimate fluorescence quantum yield using appropriate reference standards or comparative methods.
• Assess relative brightness under matched excitation and detection conditions.
• Measure baseline fluorescence background before probe activation or target response.
• Evaluate signal-to-background ratio, fluorescence enhancement factor, or ratio-change amplitude.
• Compare probe performance in buffer, organic solvent, culture medium, and serum-containing environments.
• Recommend working concentration windows for downstream assay testing.

We assess whether the probe can withstand imaging or screening conditions without rapid signal loss.

• Measure fluorescence decay under continuous or repeated illumination.
• Compare photobleaching behavior under microscopy-like, plate-reader-like, or high-content imaging-like conditions.
• Evaluate photostability across different excitation intensities, exposure times, and imaging intervals.
• Test stability in aqueous buffer, culture medium, and biologically relevant environments.
• Identify whether the probe is suitable for time-lapse imaging, long-term live-cell monitoring, or endpoint assays.
• Provide imaging-condition recommendations to reduce photobleaching and phototoxicity.

We evaluate how environmental factors affect the probe's fluorescence behavior.

• Test pH-dependent fluorescence response across relevant acidic, neutral, and alkaline conditions.
• Evaluate solvent polarity, viscosity, ionic strength, and buffer composition effects.
• Assess stability in biological media, serum, protein-containing solutions, or assay additives.
• Test temperature-dependent signal stability when required.
• Evaluate concentration-dependent aggregation, self-quenching, excimer formation, or J-aggregate behavior.
• Identify whether environmental sensitivity may interfere with mitochondrial imaging interpretation.

For responsive probes, we characterize whether the intended signal mechanism is optically robust.

• Measure fluorescence response before and after target activation, analyte binding, enzymatic cleavage, oxidation, reduction, pH shift, or ion binding.
• Characterize turn-on response, turn-off response, dual-emission change, excitation ratio change, or red/green ratio conversion.
• Determine response kinetics, endpoint stability, dynamic range, and linear detection window.
• Evaluate whether the response is reversible or irreversible when relevant.
• Test spectral separation between inactive and activated states.
• Recommend quantitative readout methods for downstream functional characterization.

For specialized imaging applications, we can extend the characterization workflow to advanced optical parameters.

• Fluorescence lifetime measurement for lifetime-based imaging or phasor analysis.
• Two-photon excitation assessment for deep-tissue or brain imaging workflows.
• Far-red or NIR emission evaluation for low-background imaging.
• AIE behavior analysis for aggregation-induced emission probes.
• Time-resolved luminescence evaluation for lanthanide or long-lifetime probes.
• Multicolor compatibility analysis with mitochondrial markers, ROS probes, Ca²⁺ probes, pH probes, lysosome markers, nuclear dyes, and cell viability indicators.

After testing, we provide a structured report to support downstream probe development and assay planning.

• Absorption and emission spectra, excitation/emission maxima, and Stokes shift.
• Brightness, relative quantum yield, photostability, and photobleaching curves.
• pH, solvent, buffer, media compatibility, aggregation, and concentration-dependence observations.
• Response-mode characterization for activatable or ratiometric probes.
• Recommended excitation/emission settings and assay concentration range.
• Risk assessment and suggestions for further functional or biological validation.