SETA BioMedicals

Plasmonics

Superior Seta Fluors for Plasmonics

Metal Enhanced Fluorescence (MEF)

Metal-enhanced fluorescence (MEF) is an important approach to increase the sensitivity thereby decreasing the detection limit of biomedical assays. There are two contributions to MEF. Firstly, under the influence of the incident light, the molecule goes to the excited state and interacts with the metal. Secondly, metal particles accelerate the fluorophore’s radiative decay rate and as a result enhance the emission. This emitter-antenna-like effect results in an increase of the quantum yield of the molecule and in a decrease of its lifetime. A simultaneous increase of the quantum yield and decrease of the lifetime is only possible when the radiative rate increases. Therefore this effect is also known as radiativedecay engineering (RDE).

SETA BioMedicals also offers superior dyes for plasmonic applications. While typical enhancement levels for conventional dyes on plasmonic platforms are in the order of 5-7-fold, SeTau-665 shows a 70-fold enhancement in ensemble measurements (Figure) and up to 400-fold in certain ‘hot spots’ in single molecule measurements [17]. Such enhancement levels have not been observed with any other type of dyes.

Dye	Absorption max. [nm]	Extinction Coefficient [M^–1cm^–1]	Emission max. [nm]	Quantum Yield [%]	Relative Photostability t_1/2 [min]
SeTau-647-di-NHS (K9-4142)	650	368,000	694	61	2614
SeTau-665-di-NHS (K9-4113)	665	140,000	715	62	9770

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While SeTau-665 exhibits excellent properties we recently developed an even brighter candidate (SeTau 647).

Emission spectra of SeTau-665 labeled antibody on a quartz (Glass) and self-assembled colloidal silver (SACS) surface.upper panels real-color photograph of labeled IqG spotted on the silver (left) and quartz (right) surfaces

Due to the large enhancements in single molecule (SM) level measurements, SM studies which were previously impossible can be successfully performed on such plasmonic platforms based on SeTau 665.

The large increase in brightness allows the reduction of the excitation power resulting in a reduced background and increased photostability. The remarkable fluorescence enhancements observed for SeTau 665 on our plasmonic platform substantially improves single molecule detection and to reduce the detection limits in sensing devices.

We offer these dyes in convenient 0.5 mg packaging for labeling of proteins and mono-reactive versions for labeling of other molecules.

Dye	Pack Size	Product Code
SeTau-647 NHS	0.5 mg	K9-4142-0.5 mg
SeTau-665 NHS	0.5 mg	K9-4113-0.5 mg
SeTau-647 NHS	0.5 mg	K9-4149-0.5 mg
SeTau-665 NHS	0.5 mg	K9-4119-0.5 mg

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Seta and SeTau dyes show much higher signal enhancement (SE) on silver surfaces (SIFs) compared to fluorophores such as Cy5, Alexa 647 or phycobillproteins (PE, APC):

SIF-coated vs. non-coated glass fluorescence signal ratio at various wavelengths tested in a model immunoassay for SeTau 665 (K9-4113) (SE ~ 70 times in bulk and SE ~ 400 times in single molecule measurements), Seta-670-mono-NHS (K8-1342), Seta-635-NH-mono-NHS (K8-1669), Seta-633-mono-NHS (K8-1663) or Seta-632-mono-NHS (K8-1642) (SE ~ 15 – 20 times) vs. Cy5, Alexa 647 or APC (SE ~ 6 - 7 times).

Product	Pack Size	Product Code
Seta-670-mono-NHS	1 mg	K8-1342-1mg
Seta-635-NH-mono-NHS	1 mg	K8-1669-1mg
Seta-633-mono-NHS	1 mg	K8-1663-1mg
Seta-632-mono NHS	1 mg	K8-1642-1mg

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Product Specifications:


		Excitation Light Sources								Free Dye					Dye Conjugate
Product Number	Product Name	380	405	436	488	532	594	635	670	Solvent	λ_Ab max. [nm]	ε [M^–1cm^–1]	λ_Em max. [nm]	QY [%]	Carrier PB 7.4	λ_Ab max. [nm]	λ_Em max. [nm]	QY [%]
K7-547	SeTau 405 NHS	•	•							PB 7.4	405	13800	518	80	BSA, D/P=8	406	518	20
K8-1342	Seta-670-NHS		•					•	•	PB 7.4	667	179000	688	7	BSA, D/P=1	681	695	35
K8-1641	Seta-632-Maleimide							•		PB 7.4	633	270000	642	5
K8-1642	Seta-632-NHS							•		PB 7.4	632	280000	641	6	IgG, D/P=1	637	647	18
K8-1663	Seta-633-NHS							•		PB 7.4	633	250000	644	7	IgG, D/P=1	637	647	26
K8-1669	Seta-635-NH-NHS							•		PB 7.4	638	136000	655	31
K8-1672	Seta-646-NHS							•		PB 7.4	646	207000	656	10	IgG, D/P=1	650	661	33
K8-1682	Seta-660-di-NHS							•		PB 7.4	661	151000	672	11	IgG, D/P=1	665	675	49
K9-4112	SeTau-655-di-NHS							•		PB 7.4	665	200000	673	25	IgG, D/P=1	657	675	31
K9-4113	SeTau-665-di-NHS	•							•	PB 7.4	665	140000	715	62	IgG, D/P=1	664	709	43
K9-4142	SeTau-647-di-NHS							•		PB 7.4	650	368000	694	65	IgG, D/P=0.5	649	691	58
K9-4149	Seta-647-NHS							•		PB 7.4	649	200000	695	61	IgG, D/P=1	648	694	59
K9-4119	SeTau-665-NHS	•	•						•	PB 7.4	664	160000	712	53	IgG, D/P=1.2	653	716	50