LSPR TRANSDUCERS FOR SENSING

PROTEIN-CARBOHYDRATE INTERACTIONS

Giuliano Bellapadrona,1 Alexander B. Tesler,1 Dan Grünstein,2,3 Laila Hossain,2 Kikkeri Raghavendra,2

Alexander Vaskevich,1 Peter H. Seeberger,2,3 Israel Rubinstein1

1 Dept. of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel2 Max Planck Institute of Colloids and Interfaces, Department of Biomolecular Systems, 14476 Potsdam, Germany

3 Freie Universität Berlin, Institute for Chemistry and Biology, 14195 Berlin, Germany

Enhancement of the signal and detection limit with Mannose-nanoparticles

Signal amplification

Man-NPs

IntroductionUltrathin gold island films prepared by evaporation on glass slides and annealing, combined with synthetically-modified carbohydrates, areused to develop localized surface plasmon resonance (LSPR) transducers for monitoring and imaging of protein-carbohydrate interactions.Specific recognition of mannose by Concanavalin A (Con A) is presented as a model for sensing using stationary and dynamic configurations.

Conclusion

Simple preparation of thetranducers.

Highly specific response.

Determination of kineticparameters.

Low detection limit.

linker

Materials

Concanavalin A( )

Gold island film( )

Mannose-linker ( )

Galactose-linker ( )

PEG-silane ( )

Wavelength (nm)

Preparation of LSPR transducers

Glass slides

Gold evaporation

Annealing* Gold island film

* 10 hours at 570 C. † Nominal thickness of the initially evaporated film.

2.5 nm†

5 nm†

15 nm†

400 600 800

0.05

0.10

0.15

400 600 800

0.05

0.10

0.15

0.20

400 600 800

0.3

0.4

0.5

Wavelength (nm)

200 nm

Extinc

tion

(abs.

u.)

Sensing of Con A – carbohydrate interactions

Blocking the glass

PEG-Silane

ReceptorSAM*

Carbohydrate

Recognition Con A

Sensing scheme

*SAM = self assembled monolayer

400 500 600 700 800

0.05

0.10

0.15

0.20

PEG-silane

Galactose SAM

1 M Con A

Extinctio

n (

abs. u

.)

Wavelength (nm)

400 500 600 700 800

0.05

0.10

0.15

0.20

PEG-silane

Mannose SAM

1 M Con A

Extinction (

abs. u.)

Wavelength (nm)

LSPR HRSEM

MannoseSAM

Galactose SAM

FTIR

Optimization Con A binding kinetics

0 300 600 900 1200 15000.00

0.01

0.02

Bu

ffe

r

Buffer

Extinction

54

5 n

m (

abs. u.)

Time (sec)

Mannose SAM

Galactose SAM

0.5 M

Con A

kon = 2.0 104 M-1 s-1 , koff = 2.6 10-3 s-1

ext t   ext   [1 exp ( t / )]

on off1/    k Con A k

0.00

0.02

0.04

0.06

0.08

0.10

0.12

(A)

(B)

(C)

(D)

5 nM Con A 50 nM Con A 500 nM Con ANo Con A

1.5 M BSA 1.5 M BSA 1.5 M BSA

Extin

ctio

n (

ab

s.

u.)

BSA + Con A

Man-NPs

1.5 M BSA

+ Con A

+ Con A