Selection and application resources for fluorescent dyes, labeling reagents and labeling services
33 articles
Learn how to calculate antibody degree of labeling from A280 and dye absorbance, apply the correct extinction coefficients, and troubleshoot free dye, incorrect corrections, and excessive labeling. Evaluate the result against performance in the intended assay.
Read more →Compare spectral compatibility, photostability, pH response and conjugation chemistry for FITC, Alexa Fluor 488 and Qihe SF488, with the limits of the available experimental evidence.
Read more →NHS Esters label primary amines, while maleimides label free thiols. Choose a route based on available functional groups, formulation and reduction requirements, then verify the labeled antibody's function.
Read more →Tris and glycine consume NHS dye. BSA and gelatin require separation from the target protein; routine buffer exchange is insufficient.
Read more →Check NHS hydrolysis and amine-containing additives, then distinguish low labeling from sample loss or reduced binding.
Read more →Calculate DOL with absorbance correction, distinguish input ratio from attached dye, and assess recovery and binding.
Read more →Cysteines may be disulfide-bound or protected. Confirm free thiols before deciding on reduction.
Read more →DTT and β-mercaptoethanol compete for maleimide; residual TCEP can also interfere.
Read more →Measure labeling density after removing free dye, then check function and changes during storage.
Read more →Use CuAAC for terminal alkynes and SPAAC for strained alkynes. Identify the handle before assessing copper compatibility.
Read more →Check reactive handles, catalyst components and copper-binding additives when conversion is low.
Read more →Use a no-handle control to distinguish labeling from adsorption, and address free dye and catalyst carryover during purification.
Read more →PEG4 and PEG12 differ in spacer length. Compare labeling, function and background at matched molar input.
Read more →Target-bound azides enable coupling; free azide reagents and sodium azide can compete for DBCO.
Read more →Use product analysis to separate low conversion from detection bias, and a no-azide control to check adsorption.
Read more →Annexin V binding requires Ca²⁺; residual EDTA or other chelators can reduce signal.
Read more →Annexin V positivity indicates accessible PS. Interpret it with membrane integrity and other apoptosis markers.
Read more →Discarding detached cells or varying collection times can change the observed Annexin V-positive fraction.
Read more →WGA labels accessible glycans. Check outline continuity for segmentation; intensity is not a direct measure of membrane amount.
Read more →WGA can be internalized by live cells. Interpret intracellular signal using timing and localization.
Read more →Fixation and permeabilization can change glycan accessibility. Compare outlines, intracellular signal and background separately.
Read more →CTB fluorescence reports GM1-associated distribution; puncta alone do not establish native lipid-raft structure.
Read more →Distinguish peripheral and intracellular CTB signals over time; one endpoint cannot establish a trafficking route.
Read more →Check conjugate-specific application data, tissue background and detection windows before assuming tracing suitability.
Read more →Free biotin occupies streptavidin-binding sites and can reduce detection of biotinylated targets.
Read more →Use unstained, streptavidin-only and non-biotinylated-probe controls to distinguish autofluorescence, endogenous biotin and adsorption.
Read more →Multivalent streptavidin can crosslink biotinylated targets, affecting live-cell motion and clustering measurements.
Read more →Couple the dye amine, isolate the intermediate and react it with target thiols; check free SMCC, competing reductants and small-molecule separation.
Read more →Distinguish free acids from NHS esters, plan carboxyl activation, amine coupling and product analysis, and retain positional-isomer identity for FAM and ROX.
Read more →NHS labels primary amines; maleimide labels free thiols. Additives and reduction requirements determine sample preparation.
Read more →Terminal alkynes pair with azides through CuAAC; DBCO pairs with azides through copper-free SPAAC.
Read more →Compare labeling density, sample recovery, specific signal and background after purification, rather than total fluorescence alone.
Read more →Compare detection windows, labeling chemistry, signal intensity, photobleaching and pH response separately.
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