Fluorescence labeling has been essential research tool in the biological researches and diagnostics since antibodies have been widely used to detect and quantify antigens. Various fluorescent materials are being conjugated to specific site of antibodies. The most common labeling site is primary amine of tyrosine residues, followed by thiol of cysteine residues. Carbohydrates that located on the Fc region where distant from the antigen binding site are considered as ideal conjugate targets, but labeling them requires extra oxidation step that converting their hydroxyls to aldehyde or ketone. Selection of suitable labeling method by balancing the advantages and limitations is the critical issue for creating an ideal fluorescent primary antibody.

Detection and tracking of proteins and other biomolecules with aptamer is high priority in the field of medical diagnostics, drug development, biological research, forensic investigations, etc. Owing to their high affinity and specificity, fluorescent aptamers are utilized in a variety of research field. Fluorescence labeling of an existing aptamer can create a powerful detecting agent, aptasensor, which enable to detect environmental pollutes, pathogens, disease markers, as well as various other chemicals/biologics/materials.

BioActs offers custom antibody/protein/aptamer fluorescence labeling service base on our accumulated bioconjugation technology. Our custom fluorescent labeling service consists of accumulated conjugation expertise, a wide selection of reactive dyes, along with choice of proper labeling technology. BioActs provide superior fluorescent dyes that display excellent fluorescence intensity, high quantum yield and photostability, and fluorescence intensity after binding to antibody/protein/aptamer maintains still excellent. Our fluorescent dyes equipped with a variety of reactive groups and cover the complete fluorescence spectral range from UV to beyond NIS region.

Fluorophores	Ex* (nm)	Em* (nm)	Spectrally similar dyes
FSD Fluor™ 488	Ex* (nm) : 495	Em* (nm) : 519	Spectrally similar dyes : Alexa Fluor 488, FAM, DyLight 549, Cy2, ATTO 550, CF 555
Flamma® Fluors 488	Ex* (nm) : 495	Em* (nm) : 519	Spectrally similar dyes : Alexa Fluor 488, FAM, DyLight 549, Cy2, ATTO 550, CF 555
FSD Fluor™ 555	Ex* (nm) : 554	Em* (nm) : 565	Spectrally similar dyes : Alexa Fluor 555, DyLight 549, Cy3, ATTO 550, CF 555
FSD Fluor™ 555	Ex* (nm) : 550	Em* (nm) : 565	Spectrally similar dyes : Alexa Fluor 555, DyLight 549, Cy3, ATTO 550, CF 555
FSD Fluor™ 594	Ex* (nm) : 591	Em* (nm) : 617	Spectrally similar dyes : Alexa Fluor 594, DyLight 594
Flamma® Fluors 581	Ex* (nm) : 581	Em* (nm) : 596	Spectrally similar dyes : Alexa Fluor 594, DyLight 594
FSD Fluor™ 647	Ex* (nm) : 650	Em* (nm) : 667	Spectrally similar dyes : Alexa Fluor 647, Cy5, ATTO 647N, DyLight 650
Flamma® Fluors 648	Ex* (nm) : 648	Em* (nm) : 663	Spectrally similar dyes : Alexa Fluor 647, Cy5, ATTO 647N, DyLight 650
Flamma® Fluors 675	Ex* (nm) : 675	Em* (nm) : 691	Spectrally similar dyes : Alexa Fluor 680, DyLight680, Cy5.5, IRDye680, CF680
FSD Fluor™ 750	Ex* (nm) : 749	Em* (nm) : 774	Spectrally similar dyes : Alexa Fluor 750, DyLight755, Cy7, IRDye 750
Flamma® Fluors 749	Ex* (nm) : 749	Em* (nm) : 774	Spectrally similar dyes : Alexa Fluor 750, DyLight755, Cy7, IRDye 750
Flamma® Fluors 774	Ex* (nm) : 774	Em* (nm) : 806	Spectrally similar dyes : Cy7.5, CF 770, DyLight 800, IRDye 800
FSD Fluor™ 800	Ex* (nm) : 774	Em* (nm) : 790	Spectrally similar dyes : Cy7.5, CF 770, DyLight 800, IRDye 800

Table 1. List of available fluorophores

BioActs provides a variety of labeling chemistry to meet any requirement in fluorescence labeling of primary antibody.

For labeling of amines : primary amine of tyrosine residues is the most common labeling site; BioActs provides NHS ester, Sulfo-NHS ester and Vinylsulfone reactive groups for amine labeling.

For labeling of thiols : depending on the structure of antibody, labeling thiol of cysteine might be a good option; BioActs provides maleimide for thiol labeling.

For click chemistry : Bioorthogonal azide-alkyne cycloaddition can introduce the label to specific region of antibodies; priori to labeling, counterpart alkyne or azide should be introduced by chemical modification.hyde, a carboxylate, a hydroxyl, or introducing a label via crosslinker are also available.

Other labeling methods : other labeling methods such as labeling an aldehyde, a carboxylate, a hydroxyl, or introducing a label via crosslinker are also available.

Once you have determined your requirements, please complete the Request form for custom antibody/protein fluorescence labeling quote and email it to the address on the form or fax to +82-32-818-8206. For questions, please contact us at support@bioacts.com.