Presentation is loading. Please wait.

Presentation is loading. Please wait.

SERS Biosensor for Endocrine Disruption Biomarker: Vitellogenin Sachin Kumar Srivastava Department of Electro-optic Engineering, & Ilse Katz Institute.

Similar presentations


Presentation on theme: "SERS Biosensor for Endocrine Disruption Biomarker: Vitellogenin Sachin Kumar Srivastava Department of Electro-optic Engineering, & Ilse Katz Institute."— Presentation transcript:

1 SERS Biosensor for Endocrine Disruption Biomarker: Vitellogenin Sachin Kumar Srivastava Department of Electro-optic Engineering, & Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva, Israel Mentor: Prof. Ibrahim Abdulhalim

2 Outline Introduction Raman-/Surface Enhanced Raman- Spectroscopy (SERS) Biosensor Endocrine Disruption Compounds Nano-Sculptured Thin Films (n-STFs): Optimization of performance Fabrication : Steps involved in developing the sensor Results: Sensing and other characterizations Summary 2

3 "A small fraction of sunlight passing through a transparent medium is scattered in all directions, with a different wavelength than the incident radiation. These shifts depend upon the chemical structure of the molecules. "A new radiation", Indian J. Phys.,2(1928)387. Indian Physicist: C. V. RAMAN Nobel prize in Physics : 1930 Raman Spectroscopy v3v2v1v0v3v2v1v0 Stokes Anti-Stokes Virtual levels Lowest Electronic State Ground State Rayleigh Scattering Raman Scattering 1 in 10 7 photons is scattered inelastically Elastic 3 Raman Scattering: Rayleigh Scattering: Inelastic

4 Fingerprint of molecular bonds and crystalline structure Very low cross-section: Applications in real life are hindered Steps of Raman development Laser applications – Dramatically improved power of excitation and Raman signal SERS effect – Enhanced intensities up to factors of Raman microscope – Decreased probe volume (light spot diameter below 1 μm) What is SERS? Large local field enhancement on rough metallic surfaces due to plasmonic and charge transfer enhancement mechanisms 4 Incident light Enhanced Raman Scattering Adsorbed molecules SERS Substrate Nanosculptured Thin Films (nSTFs)

5 Biosensor 5 A device having the role of converting a change in one physical parameter into a change in magnitude of a second different parameter which can be measured more conveniently and perhaps more accurately. Sensor Bio-sensor Any device that uses specific biochemical reactions to detect chemical compounds in biological samples. A biosensor is a self-contained integrated device that is capable of providing specific quantitative or semi-quantative analytical information using a biological recognition element which is in direct soatial contact with a transduction element (IUPAC, 1996)

6 6 Components of a Biosensor / Optical Detector Molecule imprinted gel matrix Chemical interaction SPR/SERS etc

7 n m1

8 8 Endocrine System thymus-in-endocrine-system/attachment/function- of-thymus-in-endocrine-system/ Bond 1979, Biology of Fishes General Functions of Hormones

9 9 Metals (Pb, As, Hg, Ni, Cd) Suspected Endocrine Disruptors Industrial Chemicals (Bisphenol A) Synthetic and Natural Hormones (Phytoestrogens) Pharmaceutical Drugs (Corticosteroids) Pesticides, Herbicides etc. (DDT ) Personal Care Products (Phthalates, Benzaldehyde) Diabetes Endocrine Disruptors Growth inhibition Vg : Egg yolk protein in aquatic females, excreted during sex Elevated amounts: A sign of estrogenic contamination of aquatic environment. Representative of a kind of pollution in water/aquatic species

10 nSTF Fabrication GLAD Technique SEM Images (20, 30, 40, 60 % porosity) 10

11 11 Optimization of Performance Maximum 30% porosity SERS from 4-Aminothiophenol (4-ATP) adsorbed at the n-STF Highest SERS signal due to plasmons coupling Mutual interaction between the EM fields of the localized surface plasmons (LSPs) at the neighbouring nanorods Effective electromagnetic field of the LSPs in the voids Field in voids decreases with increase in porosity The number of adsorbed molecules increases, however. Trade off between the enhancement due to rods and voids

12 Sensor Chip Development 12

13 From Laser To Spectrometer SERS Probe Extended view of SERS Probe Anti-Vg Antibody Vitellogenin BSA Sensor Chip Experimental Setup 13

14 14 Comparison of SERS Sensor vs 4-ATP Small range effect (~ 2-3 nm) Dieringer and van Duyne et al., Faradey Discuss., 2006, 132, 9-26 Negligible effect of further added molecules

15 15 Sensor Response for Varying Vg Concentration

16 16 Control Experiments Confirmation for the specificity of the sensor to vitellogenin. Another similar protein called Fetuin was used for study. Reusability and Repeatability A number of sensor chips were prepared and experiments were performed over a period of three months at different days, times and ambient conditions The sensor surface was regenerated by immersing in 50mM glycine buffer for 2 minutes in between two sensing events. Each chip was used at least three times for full sample concentration range to ensure the repeatability and reusability.

17 17 Sensor Response Curve

18 18 Summary A highly sensitive, fast Vg sensor chip utilizing SERS has been fabricated SERS can be used for sensing of bigger molecules in non-direct mode of sensing Vitellogenin concentrations as small as 5pg/ml can be detected The sensor is specific to Vg only. The repeatability, reusability and shelf life of the sensor are reasonably good For more detailed discussion of the presented results, please see SERS Biosensor Using Metallic Nano-Sculptured Thin Films for the Detection of Endocrine Disrupting Compound Biomarker Vitellogenin, SMALL (Wiley), DOI: /smll

19 19 Other Contributors/Co-authors Dr. Atef Shalabney, Laboratoire des Nanostructures, ISIS - Institut de Science et d'Ingénierie Supramoléculaires,Université de Strasbourg, 8 allée Gaspard Monge Strasbourg, Cedex Dr. Isam Khalaila, The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University, Beer Sheva-84105, Israel Dr. Christoph Grüner and Prof. Bernd Rauschenbach Leibniz Institute of Surface Modification, Permoserstrasse 15, Leipzig and University Leipzig, Institute for Experimental Physics II, Linnéstr.5, Leipzig, Germany Prof. Ibrahim Abdulhalim Department of Electro optic Engineering and Ilse Katz Institute for Nanoscale Sciences and Technology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel & School of Materials Science and Engineering, Nanyang Technological University, , Singapore

20 20 Thank You Acknowledgements 1.Council of Higher Education of the Government of the State of Israel for PBC post-doctoral fellowship 2.Singapore National Research Foundation (CREATE programme) 3.German Excellence Initiative of the Deutsche Forschungs Gemeinschaft (DFG).

21 21

22 22

23 23

24 24 I( l ) >> I S >> I aS 1 >> >> Intensity Values at ~ 1500 cm -1 α 0 - molecule equilibrium polarizability E 0 - maximum electric field ν 0 & ν - excitation and vibrational frequency, respectively r max - maximum vibrational amplitude Modulation of linear optical polarizabiliy due to presence of internal vibrations Dipole moment in a molecule

25 Mechanism of Enhancement in SERS Induced dipole moment in a molecule The molecular polarizability increases due to the formation of charge transfer (CT) metal-molecule complex. The CT band is in resonance with both the incident and scattered light. The local electric field experienced by the adsorbed molecule increases due to excitation of localized surface plasmons by both the incident and scattered photons Electromagnetic Mechanism Chemical Mechanism SERS depends on the local field to the fourth power ( ) in the vicinity of an adsorbate molecule. It is a small range effect (~ 2-3 nm). Enhancement Contribution: Enhancement Contribution:

26 26 Endocrine system is an ensemble of glands which secrete different types of hormones directly into the blood stream to maintain homeostasis. The endocrine system regulates many vital processes in a living organism, such as development, growth, reproduction and metabolism. Extrogeneous agents that interfere with the production, release, transport, metabolism, binding, action or elimination of natural hormones in the body responsible for the maintenance of homeostasis and regulation of developmental processes Endocrine System Endocrine Disruptors Chemical /Industrial waste, Natural reasons/factors Preservatives, processed food, unbalanced metabolism Pesticides, etc. Possible Factors Detection of Vg is important to understand the estrogenic contamination of aquatic environment. Representative of a kind of pollution in water/aquatic species


Download ppt "SERS Biosensor for Endocrine Disruption Biomarker: Vitellogenin Sachin Kumar Srivastava Department of Electro-optic Engineering, & Ilse Katz Institute."

Similar presentations


Ads by Google