ATTO 542, Yellow Emission

ATTO® 542 is a premium green-yellow fluorescent dye developed for demanding fluorescence imaging, molecular diagnostics, and analytical applications. The dye combines exceptional brightness, high fluorescence quantum yield, and excellent resistance to photobleaching, providing reliable signal intensity for both qualitative imaging and quantitative fluorescence measurements.

ATTO® 542 is commonly conjugated to DNA, RNA, PNA, LNA, siRNA, antisense oligonucleotides (ASOs), aptamers, peptides, proteins, and other amino-modified biomolecules using NHS ester chemistry, producing a stable amide bond with primary amino groups. Alternative conjugation strategies, including click chemistry and other orthogonal labeling methods, may also be employed depending on the application.

The dye exhibits excitation and emission maxima of approximately 542 nm and 562 nm, respectively, making it highly compatible with 532 nm, 543 nm, 552 nm, and 561 nm laser systems commonly found on confocal microscopes, fluorescence microscopes, imaging systems, and flow cytometers. ATTO® 542 provides excellent spectral separation from blue, red, far-red, and near-infrared fluorophores, making it particularly useful for multicolor fluorescence imaging and multiplex detection.

Bio-Synthesis offers ATTO 542 fluorescent dye oligonucleotide labeling services. ATTO 542 has out standing flourescence intensity, it can be used to replace, Cy3 and Cy3B. It can be excited efficiently in the range 520-555 nm.

ATTO 542  Replacement Dye

Dye	ABS [nm]	EM [nm]
ATTO 542	542	557
Cy3	550	562
Cy3B	559	570

Characteristic features of the label are strong absorption and high photostability. The dye shows a very high fluorescence quantum yield even after coupling to a bio-molecule. ATTO 542 is very suitable for oligonucleotide labeling, single-molecule detection applications and high-resolution microscopy (PALM, dSTORM, STED etc.). Additionally the dye strongly qualifies to be applied in flow cytometry (FACS), fluorescence in-situ hybridization (FISH) and many more.

ATTO 542 dye can be incorporated at any position within an Oligonucleotide. A primary amine modified oligonucleotide is used to covalently attach with dye via NHS conjugation chemistry; other cross-linking chemistries are also available depending on particular project specifications. Dual HPLC purification is used to remove failure sequences during first HPLC purification,  after labeling, the second HPLC is performed to remove unlabeled oligonucleotides and excessive dye in order to obtain a full length labeled oligonucleotide.

Bio-Synthesis offers custom ATTO® 542-labeled oligonucleotides for DNA, RNA, PNA, LNA, siRNA, ASOs, molecular beacons, aptamers, and other synthetic nucleic acids. ATTO® 542 can be incorporated at the 5′ end, 3′ end, or internal amino-modified positions, and may be combined with numerous additional modifications including quenchers, biotin, thiol modifiers, amino modifiers, PEG linkers, click chemistry handles, GalNAc, cholesterol, peptide conjugates, lipid conjugates, and other custom chemistries.

Each labeled oligonucleotide is synthesized under stringent quality standards and is available with optional HPLC purification, together with analytical characterization by HPLC, LC-MS, MALDI-TOF, UV-Vis spectroscopy, and fluorescence analysis to verify labeling efficiency, sequence identity, and product purity.

Property	Typical Value
Fluorophore	ATTO® 542
Fluorescence Color	Green-Yellow
Typical Reactive Group	NHS ester (or other conjugation formats)
Target Functional Group	Primary amino groups
Bond Formed	Stable amide bond
Excitation Maximum	542 nm
Emission Maximum	562 nm
Laser Compatibility	532 nm, 543 nm, 552 nm and 561 nm lasers
Filter Compatibility	Cy3 / TRITC filter sets
Compatible Oligos	DNA, RNA, PNA, LNA, siRNA, ASO, Aptamers
Typical Labeling Sites	5′ end, 3′ end, internal amino modifiers

Trademark Notice: ATTO® is a registered trademark of ATTO-TEC GmbH. Bio-Synthesis provides custom conjugation services using customer-specified or commercially available fluorescent dyes and is not affiliated with or endorsed by ATTO-TEC GmbH.