Remote sensing the liquid-liquid interface: detecting micro-transport across cell membrane

for better drug delivery

1Tapas Goswami, 2Debabrata Goswami

1School of Technology, The Glocal University, Saharanpur2Department of Chemistry, Indian Institute of Technology Kanpur

1

Interface

Neat water

Dye solutionin DCM solvent

Cell membrane

Drug delivery

Objective

Quantronix coherent

Ultrafast Laser

mimic

bulk

Affected cell

Blood

2

indocyanine green dye (IR-125)

Molecules of Choice

indole maroon dye (IR-144) (Tricarbocyanine dye)

IR125 dye is used in medical diagnosis

Has potential application in photodynamic therapy

S0

S1

T

Journal of Photochemistry and Photobiology A: Chemistry 128 (1999) 101–109

triplet-state molecules could convert ground-state triplet-oxygen to excited singlet-state oxygen with high cell killing potential

3

triplet-state

Interface Setup

T. Goswami S.K.K. Kumar, A. Dutta, D. Goswami, J. Phys. Chem. B 113 (2009) 16332-39

Quantronix coherent

Ultrafast Laser

4

Experimental Schematic

Laser system

5

Excited state life time of the dye @ Different Positions with respect to the Interface

0 2000 4000 6000 8000 10000

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Nor

mal

ized

Pro

be T

rans

mit

tanc

e

Probe Delay (fs)

raw data Z= -3mm fitted data Z= -3mm raw data Z= -700m fitted data Z= -700m raw data Z= -500m fitted data Z= -500m raw data Z= -300m fitted data Z= -300m raw data Z= -100m fitted data Z= -100m

Bulk

Interface

S0

S1

T

Bulk

interface

T. Goswami S.K.K. Kumar, A. Dutta, D. Goswami, J. Phys. Chem. B 113 (2009) 16332-39 6

-3000 -2500 -2000 -1500 -1000 -500 00

500

1000

1500

2000

2500

3000

3500

exc

ited s

tate

life

tim

e ( fs

)

Z (m)

Excited State Lifetime for IR125 in DCM interfaced with water at different Z-Positions

InterfaceBulk

Exc

ited

stat

e lif

e tim

e (f

s)

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Proposed Mechanism

Water layer

DCM layer

(a) (b)

Water layer

DCM layer

Interface

Bulk

T. Goswami S.K.K. Kumar, A. Dutta, D. Goswami, J. Phys. Chem. B 113 (2009) 16332-39 8

Conclusion

1. Excited state relaxation rate is observed to be significantly slower in case of interfacially perturbed dye molecules near the DCM-water interface compared to that in the bulk solution.

2. Near the interface the excited state life time of the dye molecule is more.

3. Interfacially perturbed molecule has more triplet state lifetime, so more effective for photodynamic therapy.

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THANKS

10