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PEGylated Gold Nanoparticles Conjugated to

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1 PEGylated Gold Nanoparticles Conjugated to
Monoclonal F19 Antibodies as Targeted Labeling Agents for Human Pancreatic Carcinoma Tissue February 26, 2009 Gary Craig Department of Chemical and Biological Engineering University of Maine

2 Sections of Talk 1. Pancreatic Cancer 2. Noble Metal Nanoparticles
3. Functionalization and Bio- Linking 4. Tissue Studies 5. Conclusions 6. Future Directions

3 Application to Pancreatic Cancer Detection
Pancreatic Cancer produces low density tumor masses: Not visible early by screening methods (CT scanning) During surgical removal, the tumor margins are difficult to find. Early diagnosis – whole animal imaging (x-ray tomography) Help the surgeon identify cancer margins during surgery.

4 Histology of Pancreatic Adenocarcinoma (Standard Diagnostic Method)
Standard Histology Stain Labeled for Cancer Stroma Healthy Pancreatic Tissue

5 Histology of Pancreatic Adenocarcinoma
Standard Histology Stain Cancer Stroma Labeled Pancreatic Cancer Tissue

6 Interconnected Themes of Interest in our Lab
Observation of (Bio)-Chemical processes at the single-molecule level in heterogeneous systems (1) Sample Driven Design Constraints: Question (material or animal system) Geometry Chemical/Physical Environment Time scale (3) Measurement (Tissue) Nanoprobe Photophysics – Understanding Chemical and Physical characteristics (2) Developing nanoprobes for imaging at the single molecule level (Engineering and synthesis) Development of imaging tools for single molecule detection

7 We are Engineers Design Requirements 1. Small, shape and size tunable
2. Non-toxic 3. Biocompatible (stable, non-aggregating). 4. Long-circulating in blood – not rapidly removed by the body 5. Target Specific (sticks only to “cancer”) 6. Significant improvement in image contrast 7. Cost effective (health care $$$) We are Engineers

8 Metallic Nanoparticles – Batch Synthesis
Metal salts are brought to boil in aqueous solution (HAuCl4.H2O for gold) A reducing agent is added (sodium citrate) and reaction proceeds for 2 minutes Excess reducing agent electro-statically stabilizes against aggregation 100 oC Ostwald Ripening Stirring time Au3+ Au0 Reducing Stable Colloid Size depends on the molar ratio of metal ion and reducing agent Rod shaped particles formed via surfactant templating (CTAB, TOAB)

9 Metallic Nanoparticles
Gold (spheres) Gold (Rods) We are interested in designing our own nanoprobes, to have engineered properties which enhance that capabilities of our imaging technique. This process is already underway in our group and part of a larger IMB effort. Photo-physics?? Size and geometry tunable (2.5 – 65 nm) Very expensive to buy (spheres), relatively cheap and easy to make

10 Systems Under Investigation
Metals: Silver Nitrate (AgNO3) Gold Acid Chloride (HAuCl4) Reducing Agents: Sodium citrate (mild) Sodium borohydride (strong) Surfactants: Cetyltrymethylammonium Bromide (CTAB) Polyethylene Glycol

11 Particle Stability Ideally particles should not agglomerate
Typical gold synthesis produces a stable colloid, but not stable enough to be used in vivo Changes in temperature, pH, concentration will cause agglomeration

12 Part I. Simple Light Scattering
Elastic Scattering (Rayleigh) – energy of the photon is unchanged A light induced oscillation of conduction electrons gives rise to a peak in the absorption curve (Plasmon Resonance). Small particles scatter shorter wavelengths, Larger particles scatter longer wavelengths

13 Metal Nanoparticle Light Scattering
100ms integration Full Color Scattering Spectra small large mixed 50 mm Mixed Sample Spectra Darkfield Scattering Image

14 Silver Nanorods

15 Surface Modification Covalently bonding a polymer to the surface of the particle sterically prevents agglomeration Thiol linked polyethylene glycol (PEG) is convenient for gold particles Provides point of attachment of targeting molecule Polyethylene Glycol Dithiol (Wolfgang Eck)

16

17 Antibodies Proteins produced by the immune system
Used to target foreign material such as bacteria or viruses Convenient targeting mechanism

18 Monoclonal Antibody F19 Developed at the Ludwig Institute for Cancer Research Specific to FAP α (expressed in stroma) Coupled to PEG via NHS/EDC chemistry Purified by Size Exclusion Chromatography

19 Y Y Y Y Y Y Design Approach
mAb F19 functionalized gold nanoparticles for visualization of pancreatic cancer stromal cells Y Y Y Y Y Y Y The PEG coating enhances particle biocompatibility and eliminates agglomeration (Electro-static and Steric). Antibodies can be attached via the terminal carboxy groups using standard NHS/EDC coupling chemistry. F-19 antibody coupled via the carboxy moiety (Ludwig Institute) – Binds to glycoproteins on stromal cell surface

20 PEG Dithiol Synthesis Synthesizing our own allows us to control length and functionality

21 Gold Nanoparticles Narrow size distribution Broad size distribution
(40 mm images)

22 SEC Column Fractions The antibody-functionalized gold nanoparticles can be fractionated according to size and antibody content by size exclusion chromatography (SEC). They can be prepared free from any non-bound antibody and are fully stable over a period of at least several weeks.

23 TEM images of SEC fractions.

24 NIH 3T3 Cells Labeled with WGA conjugated Gold Nanoparticles

25 Cancer 40x + Au-PEG - Control
Cancer 40x + Au-IgG Control B 35 mm A 35 mm

26 A. B. Comparison of stained vs Au-mABF19 lableled
35 mm 35 mm A. B. Histological Staining Labeling with F19 Conjugate

27 Cell / Ex Vivo labeling - Preliminary
< 5 mm pancreatic tissue sections Negative control Immunohistochemically Stained F-19 Nanoparticle Labeled Optimization of nanoparticle geometry for optical contrast Reproducibility Lots of tissue studies Nanotoxicity (John Wise – USM)

28 Immunoelectron Microscopy
Gold Scatters Electrons! Labeling with Conjugates Fixation and Embedding Viewed by TEM Labeling or Tissue Expression?

29 Conclusions: Gold nanoconjugates have great potential in cancer diagnosis and treatment due to their optical contrast Pegylated gold is extremely stable MAB-F19 based conjugates show promise but more characterization is necessary.

30 Future Directions Hard to get F19
Problems with animal model – Different antibody? Other contrast mechanisms -CT Contrast

31 References W J Rettig, P Garin-Chesa, H R Beresford, H F Oettgen, M R Melamed, and L J Old. Cell-surface glycoproteins of human sarcomas: differential expression in normal and malignant tissues and cultured cells. Proc Natl Acad Sci U S A May; 85(9): 3110–3114. W. Eck, G. Craig, A. Sigdel, G. Ritter, L. Old, L. Tang, M. Brennan, P. Allen and M. Mason, PEGylated Gold Nanoparticles Conjugated to Monoclonal F19 Antibodies as Targeted Labeling Agents for Human Pancreatic Carcinoma Tissue. ACS Nano, 2(11): , November 2008. G.D. Kymionus, M.M. Konstadoulakis, E. Leandros, A. Manouras, A. Apostolou, D. Alexiou, S. Katsaragakis and G. ANDROULAKIS. J.R. Effect of Curative versus palliative surgical treatment for stage III pancreatic cancer patients . Coll.Surg.Edinb., 44, August 1999,

32 The Mason Group Thank You!
Gary Craig Matt King Ray Kennard Ed Allgeyer David Paul Sara Sterling Ben Freedman Sushil Kadka Aruna Sigdel Mike Browne Adam Pongan Eric Young Jennifer Brown Eben Estell Maria Collins Collaborators William DeSisto Sam Hess David Neivandt Peter Allen Wolfgang Eck Thank You! Support: NSF, Memorial Sloan Kettering Cancer Center

33 Excessive intake of Silver colloids (Argyria)
Questions?


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