Fluorescein PEG aldehyde

Fluorescein PEG Aldehyde, FITC-PEG-CHO

Fluorescein PEG Aldehde (FITC-PEG-CHO) is one of Nanocs’ reactive fluorescent PEG dyes that can react with N-terminal amines. Fluorescein is a bright green fluorescent dye with excitation/emission wavelength at 495 nm/515 nm. Aldehyde group is reactive toward amines, hydrazide or oxyamine groups from pH 5-9. Unlike amine reactive succinimidyl ester group (NHS), aldehyde can react with N-terminal amine groups at acidic pH, a condition sometimes required for certain bioconjugation reactions. Aldehyde reacts with amine group to form an intermediate Schiff bond. Further reduction with hydride will form a stable C-N bond. Reaction between aldhyde and other groups allows site-specific conjugation and labeling of fuorescein dyes to desired position on targeted molecules. Conjugated FITC dye can be easily detected by common fluorescent instruments under FITC channel. PEG linker between FITC and aldehyde offers higher water solubility, less steric hindrance and enhanced stability. Compared to other commonly used fluorescent dyes, Nanocs pegylated fluorescent dyes are more stable and easier to use.

Physical Properties:

• Appearance: Orange/yellow solid;
• Solubility: Soluble in water, DMSO, DMF;
• Reactive group: Aldehyde (-CHO);
• Reactive toward: N-terminal amines, primary amine, aminooxy, hydrazide, etc.;
• Ex/Em wavelength: 495 nm/515 nm;

Storage Conditions:

• Store at -20 ⁰C. Protect from light.

Reaction Procedures:

Generally, a 5- to 10-fold molar excess of Fluorescein PEG aldehyde over the amount of amine-containing molecules (such as protein or antibody) results in sufficient conjugation.

Materials Required:

• Pegylation buffer: Amine-free aqueous buffer, pH 5.0~6.5.
• FITC PEG aldehyde stock solution: 5-10 mg in 1 mL conjugation buffer.
• Washing solution: Distilled water or any aqueous buffer.

Reaction Steps:

Dissolve targeted moleculess in pegylation buffer. Estimate the concentration of primary amine groups on the targeted materials. Add FITC PEG aldehyde stock solution to the targeted conjugation materials with the final concentration keep at least 10 mg/mL. Allow mixture agitates at room temperature for 2~4 hrs at room temperature or overnight 4 ⁰C. After reaction, C=N bond can be reduced by sodium borohydride. Conjugate can be purified either by size exclusion chromatography or dialysis.