Probe Characterization Service

We begin by reviewing the probe structure, intended biological target, response mechanism, detection platform, and downstream application.

• Review probe type, target analyte, mitochondrial process, and expected signal output.
• Define whether the probe requires optical characterization, functional validation, or both.
• Clarify intended assay format, such as confocal imaging, live-cell imaging, flow cytometry, plate reader, high-content imaging, organoid imaging, or tissue imaging.
• Identify potential risks, including weak fluorescence, spectral overlap, photobleaching, poor solubility, nonspecific staining, pH interference, cross-reactivity, or cytotoxicity.
• Design a staged characterization plan to prioritize the most critical performance parameters.

We first evaluate the probe's optical properties under controlled conditions to determine whether it is suitable for the intended imaging or detection platform.

• Measure absorption and emission spectra.
• Determine excitation/emission maxima, Stokes shift, and spectral bandwidth.
• Evaluate fluorescence intensity, brightness, quantum yield, and signal-to-background ratio.
• Test photostability under imaging-like or plate-reader-like conditions.
• Assess solvent, buffer, pH, serum, culture medium, and temperature effects.
• Evaluate aggregation, self-quenching, concentration dependence, or AIE behavior.
• Recommend excitation/emission settings, filter compatibility, and working concentration ranges.

For responsive probes, we evaluate whether the probe reacts or responds correctly to the intended target while minimizing interference from related species.

• Test response to target analytes or triggers such as H₂O₂, O₂•⁻, GSH, Ca²⁺, Mg²⁺, pH shift, NADH, ATP/ADP, enzymes, or mitochondrial stress-related conditions.
• Measure response kinetics, dynamic range, detection limit, linear response range, and endpoint stability.
• Evaluate selectivity against interfering ions, ROS/RNS/RSS, thiols, cofactors, amino acids, proteins, and biological matrix components.
• Determine whether the response is reversible, irreversible, enzyme-triggered, binding-based, or environment-sensitive.
• Compare performance in buffer, cell culture medium, and other assay-relevant conditions.

We then evaluate whether the probe performs properly in cellular systems and localizes to the intended compartment.

• Optimize probe concentration, loading time, washing conditions, and imaging window.
• Evaluate cell permeability and intracellular retention.
• Assess cytotoxicity and phototoxicity under intended assay conditions.
• Perform co-localization imaging with mitochondrial markers.
• Check nonspecific accumulation in lysosomes, nuclei, cytosol, plasma membrane, or extracellular background.
• Evaluate whether mitochondrial localization depends strongly on membrane potential.
• Test fixation compatibility if the probe will be used in endpoint assays.

After localization and compatibility are confirmed, we test whether the probe responds correctly in biologically relevant perturbation models.

• Use positive and negative biological controls.
• Test mitochondrial uncouplers, oxidative stress inducers, antioxidants, ionophores, metabolic inhibitors, mitophagy inducers, lysosomal modulators, apoptosis inducers, or pathway-specific compounds.
• Compare probe signal with orthogonal readouts such as membrane potential, ROS, ATP/ADP, NADH/NAD⁺, Ca²⁺, pH, apoptosis, cell viability, oxygen consumption, or mitochondrial morphology.
• Establish dose-response and time-course relationships.
• Confirm whether signal changes reflect the intended biological event rather than nonspecific toxicity, autofluorescence, probe leakage, or cell death.

Probe characterization also supports conversion of a fluorescence response into a reproducible quantitative assay.

• Define quantitative metrics such as fluorescence intensity, fluorescence ratio, ΔF/F₀, red/green ratio, mitochondrial/cytosolic ratio, puncta count, co-localization coefficient, or morphology score.
• Optimize imaging parameters, plate format, seeding density, staining protocol, acquisition timing, and replicate design.
• Evaluate signal window, assay robustness, intra-plate variation, inter-day reproducibility, and sensitivity.
• Develop image-analysis workflows for mitochondrial segmentation, puncta detection, organelle overlap, or cell-level response profiling.
• Prepare assay recommendations for high-content screening, functional profiling, or downstream validation.