Nanomedicine

1. Nanomedicine

2. First, a short video https://www.youtube.com/watch?v=2VcNpl8-PRI&feature=youtu.be From the European Nanomedicine Nanotechnology Platform http://www.etp-nanomedicine.eu/public

3. Introduction – Goals of Nanomedicine • End goal of nanomedicine is improved diagnostics, treatment and prevention of disease For a great review see: http://www.wtec.org/nano2/Nanotechnology_Research_Directions_to_2020/ See also https://commonfund.nih.gov/nanomedicine/index (US National Institutes of Health)

4. Introduction • Nanotechnology holds key to a number of recent and future breakthroughs in medicine

5. Nanoparticles for Pathogen Detection Fluorophore Release Nanoparticle Probe Targeted RNA • Gold nanoparticles can be functionalized with thiolated oligonucleatides. • Bound to the oligonucleatides are fluorophores which are quenched by their proximity to the nanoparticle. • When the targeted RNA (H2N2, HIV or a cancer) bindes to the oligonucleatide, the fluorophore is released and becomes fluorescence. • The fluorescence can be detected in a BioMEMS device. • Challenge is developing oligonucleatides with high selectivity for the target RNA.

6. Nanoparticles for Targeted Detection of Cancer Healthy Cells Breast Cancer Cells • As an example, nanoparticle probes were developed by Chad Mirkin at Northwestern Univ. that target the survivin RNA sequence known to exist in a certain breast cancers. • Experiments are done ex-vivo. • On the left, cancer cells fluoresce. • On the right, healthy cells show minimal fluorescence.

7. Nanoparticles for In-vivo Detection of Pathogens • Fluorescence is not a viable option in-vivo, but magnetic tagging works very well. • Harmless virus can used as a building block to produce contrast agents that can be used in Magnetic Resonance Imaging (MRI). • Here, magnetic metal ions are bonded to the virus as are molecules that bind to cancer cells. • A full body MRI scan detects these contrast agents and even very small tumors throughout the body

8. Targeted Delivery to Tumors • Goal is to inject treatment far from tumor and have large accumulation in tumor and minimal accumulation in normal cells/organs.

9. Cancer Treatments • Tumor penetration is a key issue for successful chemotherapy

10. Nanoparticle use in Cancer Treatments • Because of their small size, nanoparticles can pass through interstitial spaces between necrotic and quiescent cells. • Tumor cells typically have larger interstitial spaces than healthy cells • Particles collect in center bringing therapeutics to kill the tumor from inside out.

11. Nanoparticle Targeting and Accumulation • To maximize their effectiveness, the microenvironment of the tumor must be quantified and vectors developed to specifically target the tumor. • These treatment approaches have shown great promise in mice. Necrotic Quiescent Proliferating Therapeutic

12. First Successful Nanomedicine - Abraxane

13. Making Gold Nanoparticles • AuCl4- salts are reduced using NaBH4 in the presence of thiol capping ligands • The core size of the particles formed can be varied from <1 nm to ~ 8 nm • The surface functionality can be controlled through the choice of thiols • Diffusion speed can be controlled by length of thiols

14. Nanoparticles as Sensors and Therapeutics • Glutathione (GSH) provides a selective and tunable release mechanism • Once inside cells, fluorophores and drugs selectively dissociate

15. Nanoparticle Success • Both cationic and anionic particles penetrate and accumulate in tumors. • However, only cationic particles diffuse fully throughout the tumor. • Work of Neil Forbes and Vince Rotello at UMASS

16. Alternatives to Nanoparticles - Surfactants • Surfactants are composed of a hydrophilic head and a long hydrophobic tail • When dissolved in water above the critical micellar concentration (CMC) surfactants can self-assemble into large aggregate • Spherical micelles are around 10nm in size • Hydrophobic drugs can be encapsulated and in their core and delivered throughout the body or to a specific target.

17. Nanotechnology in Tissue Engineering – Cartilage Replacement • Samuel Stupp at Northwestern has shown that nanotechnology can be use to regenerate severed spinal cords. • Two polypeptides amphiphiles are used that when mixed in an aqueous solution self assemble into a nanotube • As seen on right, these nanotubes display peptide growth factors. • In mice, these systems have been shown to promote axonal outgrowth and bridging of injured areas (bottom right).

18. Nanotechnology in Tissue Engineering – Cartilage Replacement • Because cartilage doesn’t have vasculature and cannot repair itself, accepted treatments have been mostly mechanical in their approach. • Joint lubricants: • Simple and effective at short-term pain relief but do not address cause of the problem or repair any damage. • Debridement/lavage/microfracture: • Small lesions are repaired by shaving or shaping contour of cartilage. • Microfracture penetrates subchondral plate (bone) and actually causes growth of fibrocartilage – a lesser form, not desirable. • Total joint replacement: • Addresses problem and generally allows full repair, but • Very invasive procedure, native tissue removed • Prostheses do not last a lifetime in active patients. • Nanotechnology approach • Regrow patient’s own cartillage in-vivo to repair damage www.hughston.com/hha/

19. ACT Methods • A popular tissue engineering approach has been to introduce new cells, via autologous chondrocyte transplantation/implantation (ACT/ACI). • Some of the earliest work by Benya and Shaffer (1982) showed it was possible to isolate and culture chondrocytes. • More interesting result was that when cultured in vitro, the cells differentiated and changed their phenotype to produce a lesser quality collagen. • Need better tissue scaffolds – nanotech. Important to tissue engineering:Cells will differentiate purely based on mechanical stimulus. Genzyme ACT method: FDA approved 1997 biomed.brown.edu

20. Hydrogels – Self Assembly • Hydrogels have applications in drug delivery and tissue engineering • Regenerating cartilage and other tissue requires scaffolds with similar modulus and other mechanical properties → Need to develop stiffer, tunable hydrogels • We investigated Polylactide-Polyethylene Oxide-Polylactide triblock copolymers. • Systems are biocompatible with a hydrophobic ends (PLA) and a hydrophilic center (PEO) which self-assembles in water and can form a gel under the right conditions Reinforced Through Addition of Nanoparticles Gelation CMC Micelle Triblock Copolymer Gel

21. Rheology of Hydrogels • The hydrogels formed are very stiff with elastic modulus on the order of 1-10 kPa. • Within range of moduli of several human tissues including cartilage. • Gels formed from polymers with higher degree of polymerization maintain a high storage modulus even at physiological temperatures (370C). • In-vivo applications feasible. • Rheological response of these polymers can be easily tuned by varying the crystallinity or block length of PLA or through addition of nanoparticles. R-Lactide Amorphous Core L-Lactide Crystalline Core Khaled et al. Biomaterials (2003)

22. Photocrosslinking Hydrogels for Cartilage Replacement • An alternate approach is to make the hydrogel from polymers that can be crosslinked after injection. • From Jennifer Elisseeff’s lab at Johns Hopkins University. • Photo-polymerizing the hydrogel increases its modulus, allowing the appropriate phenotype of cartilage to be expressed and protecting damaged area from wear.

23. Keeping Things Clean – Antimicrobial Surfaces • Silver is an excellent anti-microbial agent • Silver nanoparticles are now being added to fibers of clothing and bandages as well as being incorporated into surfaces in hospitals to reduce the rate of bacterial infections • When co-extruded with a polymer like PLLA, the silver is released slowly over time and has been shown to effectively kill bacteria

24. Introduction – Goals of Nanomedicine • One goal is to ultimately integrate detection, diagnostics, treatment and prevention of disease into a personalized single platform

25. BioMEMS for Screening and Diagnostics • Goal is to develop handheld diagnostic devices for personalized medical testing and treatment Biomedical Analysis and Communication System Disposable Diagnostic BioChip

26. BioMEMS – Micro and Nanofluidics

27. UMass Institute for Applied Life Sciences (IALS) http://www.umass.edu/ials/ See also the IALS Center for Personalized Health Care Monitoring http://www.umass.edu/cphm/

28. Extra slides

29. Nanoparticle Encapsulation for Drug Delivery • Nanoparticle shells can be formed around spherical droplets • A.D. Dinsmore, et al., Science 298, 1006 (2002), Y. Lin, et al., Science 299, 226 (2003) • Shells are porous at lengthscales much smaller than size of nanoparticle. A: Scanning electron microscope of a dried 10-μm-diameter colloidosome composed of 0.9- μm-diameter polystyrene spheres.

30. Why Particles Adsorb to Interfaces [Pickering (1907); Pieranski PRL 45, 569 (1980)] I. Particle (P) away from interface: Interfacial Area = A P surface tension (Oil) Energy = AgO/W + 4pR2gP/O (Water) II. Particle sitting astride the interface (half-in, half-out): Energy = (A-pR2)gO/W + 2pR2gP/O+ 2pR2gP/W • If |gP/O –gP/W| < gO/W/2, then adsorption reduces surface energy.

31. oil-nanoparticle suspension, w/ droplets water droplet: mm to mm nm Nanoparticles At Interfaces • Nanoparticles can be functionalized, cross linked or sintered to make shell permanent, strengthen shell or change shell permeability.

32. Nano-Encapsulation for Drug Delivery • By making the holes between nanoparticles approximately the same size as the drug you want to administer you can get a constant release rate – avoids spikes in dosage. • Can also allow encapsulation of hydrophobic drugs which are difficult to get into you mostly water body. Standard Diffusion Based Drug Delivery Nano-Encapsulated Drug Delivery Drug Concentration in Patient Time