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Introduction to Nanomedicine and Nanotechnology

Wayne State UniversitySeptember 8, 2015

Guangzhao MaoProfessor and Chair

Department of Chemical Engineering and Materials ScienceNanoengineering

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Course Organization

• Syllabus• Presentations• Final exam

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Length Scales (Part I)

Gold Nanoparticle3.5×10-9 m

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Length Scales (Part II)

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Length Scales (Part III)

Nanometer

US FDA

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What is nanotechnology?

• Narrow definition– “Nanotechnology is the engineering of functional systems

at the molecular scale.” -Center for Responsible Nanotechnology

• Broad definition– “Nanotechnology is the understanding and control of

matter at dimensions of roughly 1 to 100 nm.” -National Nanotechnology Initiative

• We will follow the broad definition for nanotechnology, since we need to understand the properties of small objects before we can build machines from them.

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Nanotechnology Products

• Nano ski wax (better performance)• Nano car wax (a shinier car)• Self-cleaning clothes (water repellent)• Nano-ceramic coatings on photo papers• Cell phones (data storage, LCD display, batteries)• Man-made skin grafts• Targeted drug delivery• Bandages with silver nanoparticleshttp://www.nnin.org/news-events/spotlights/nanotechnology-products

Advantages of Nanoconjugates over Free Drugs

Targeted therapy lowers drug dosage, toxicity, and unwanted distribution to tissues/organs.

Drug solubility can be improved by conjugation. Multivalent binding results in stronger and more contact

area with the cell membrane leading to more efficient cell entry.

Local concentration of drugs at target sites is increased. Conjugates remain at injection sites longer than free drugs. Fast vs. slow release to reduce the number of injections.

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Examples of Nano Research in the Mao Lab

• Targeted drug delivery– Gold nanoparticles– Biodegradable polymers

• Nanosensors– Organic conductors

• Nanotoxicity – Human embryonic stem cells

Targeted Delivery of Theophylline (THP)

Study design: IRB-approved, double blind, placebo-controlled, crossover study

Enrolled 24 patients over 2.5 years. Only 10 completed both arms (drug and placebo) of the study. Significant side effects: nausea, vomiting, restlessness,

insomnia. Caused by theophylline being exposed to all CNS neurons after

systemic injection.

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Our Approach and Innovation

Deliver theophylline exclusively to respiratory neurons to mediate diaphragm recovery by chemical conjugation to GNP carrier and WGA-HRP retrograde transport.

We are the only lab in the world using targeted nanotechnology to achieve motor recovery after spinal cord injury in rats.

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Collaborator: Dr. Harry Goshgarian (NIH HD-31550)

Nanoconjugate Synthesis

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Transmission Electron Microscopy

MSA-GNP20 nm

Final productMSA-GNP/pro-THP

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Nanoconjugate Characterization Transmission electron microscopy Atomic force microscopy Thermogravimetric analysis Zetasizer UV-vis spectroscopy

Final product size is 6.5-15 nm with one protein conjugated to 2 GNPs.

Lt Diaphr (top EMG) = injured side Rt Diaphr (bottom EMG) = uninjured side Horizontal Scale in Seconds, Vertical Scale in Volts AuHRP 16 Hemisection verification pre injection of nanoconjugate on Day 2

4 days after nanoconjugate injection

10 days after nanoconjugate injection

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Nanoconjugate with 3.5nm GNP

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Summary of Our Findings

Nanoconjugates based on GNP are effective in drug delivery targeted to spinal cord injury.

Dosage: dosage has been optimized for two drugs (THP and DPCPX).

THP: 0.06 mg/kg (conj.) vs. 15 mg/kg (free) or 0.4% DPCPX: 0.4 g/kg (conj.) versus 0.1 mg/kg (free) or 0.4%

GNP size: 3.5 nm and 15 nm GNPs both promote recovery. Drug release rate modulation.

DPCPX

Biodegradable Polymers for Localized DNA Delivery

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Implantable Substrate

PolycationDNA

PolycationDNA

PolycationDNA

PolycationDNA

Polycation

CellPolyplex

Filmdegradation

Collaborator: Dr. Wei-Zen Wei

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wks0 2 4 6 8 10

Bi-weekly electrovaccination with a mixture of 1-2 antigen DNA plus cytokine DNA

A Typical Vaccination Protocol

It may be advantageous to deliver individual antigen and cytokine genes in sequence, rather than at the same time.

Controlled and timed release of plasmids from a layer-by-layer (LbL) film may reduce or eliminate repeated vaccination.

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Sequential DNA Delivery from Layer-by-layer (LbL) Films

How to achieve sequential DNA release?– Use a non-diffusing polyelectrolyte– Use a PLGA barrier layer

How to increase transfection (in vitro)?– Achieve sequential DNA release– Cross-link film– Use cell adhesion protein/peptide

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(PAA/DNA)n Film Disassembly

0min 38min 54min 64min

72min 83min 86min 97min

10 μm

3 μm × 17 μm

6 μm × 19 μm

9 μm × 15 μm

0 17 23 38 54 64 72 83 86 970%

20%

40%

60%

80%

100%

0

100

200

300

400

500

600

Time (min)

Th

ickn

ess

Th

ickn

ess

(nm

)

Film disassembly is conducted in dithiothreitol (DTT) solution.

Film completes disassembly in 100 minutes.

Degraded film products are micron size particles.

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(PAA/DNA)n with Barrier Film Disassembly

Film completes disassembly in 5 days.

Degraded film products are nanometer particles.

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Summary of Our Findings

Sequential DNA release has been achieved by using a non-diffusing polyelectrolyte.

Dual-staged release has been achieved by PLGA spin coated layer.

DNA transfection from the film has been improved by:– Sequential DNA release– Cross-linking– RGD-b-PEI– Fibronectin – Hyaluronic acid

In vivo studies have not been conducted.

Developing Low-cost Nanowire Sensors Based on a Seed-

mediated Solution Process

Guangzhao Mao

“I am not aware of any experiments to determine the smallest amount of solid that is needed to make this procedure [that is, the crystallization] succeed.” – Wilhelm Ostwald (1897).

Seed-mediated Crystallization

• Crystallization is a key chemical engineering unit operation used to purify solid compounds from the liquid solution.

• Seed-mediated crystallization is used by chemical, pharmaceutical, and biotech industries to control the crystallization process.

• We are investigating seed-mediated crystallization when the seed is a nanoparticle.

Seed-Mediated Crystallization• A seed lowers nucleation

energy barrier and promotes nucleation at lower supersaturation.

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ationsupersatur :

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volumemolecular :

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Advances in Crystal Growth Research, Elsevier, 2001.

Nucleation capacity

Normalized seed size

Nanoparticle-mediated Growth of Carboxylic Acid Nanowires

250 nm

MUA:CdSe = 0.38:1Z-range = 5 nm

125 nm

MUA:CdSe = 0.50:1Z-range = 8 nm

Mao et al. J. Am. Chem. Soc. 2004, 126, 16290-16291.

• Radially oriented nanocrystals on highly curved seeds.

Cacciuto et al. Nature 2004, 428, 404.

5

sR

7

sR

Carboxyl-terminated NP

Methyl-terminated NP

Seed-mediated Nucleation

Conductive Nanowires by Electrocrystallization

Tetrathiafulvalene (TTF)-based charge transfer salts.

[100

[001]

eBrTTFBrTTF 76.076.0 76.0

Electron Donors Electron Acceptors

S

SS

S TTF

S

SS

S S

SS

S

BEDT-TTF

Se

Se

Se

Se

TMTSF

Br-

I-

PF6-

ClO4-

N

N

N

N TCNQ

Electrocrystallization of TTF Salt

10 μm

a b

100 nm

AuNP

(TTF)Br0.76

[001]

[100]

dc

1 μm

Mao et al. J. Phys. Chem. C, 118, 18771-18782, 2014.

TTFBr0.76

Nanorod

Potentiostat

Referenceelectrode

Counterelectrode

HOPG

GNP

Workingelectrode

Nanowire Deposition on

Microelectrode

Figure . (a) Proposed microelectrodes for the electrochemical deposition of TTF-based nanowire crystals as interconnects. (b) Alternative design of microelectrodes that allows tuning of the separation distance between opposing contacts. (c) An actual substrate fabricated based on the design (b).

a

b

c

Impedance Vapor Sensors• Nanowire sensing is based on the change of nanowire electrical properties

(e.g., electrical conductance, resistance, and impedance) upon the adsorption of an analyte on the surface of the sensor.

• The high sensitivity of nanowire sensors is derived from their large surface-to-volume ratio.

• The impedance is equal to the voltage-time function divided by the current-time function. It consists of a real in-phase part (resistance, R) and an imaginary out-of-phase part (capacitance, C).

• Our nanowire sensors will detect vapors by impedance change and we will optimize the performance by selecting appropriate range for both R and C curves.

• Our applications will be governed by sensitivity, readout time, life span, pre-treatment, stability, and scaling.

• We are looking analytes of interest to our customers while doing proof-of-concept with generic analytes (acetone, ammonia, and hydrogen sulfide).

Impedance Response to Different Vapors

2 116 230 344 458 572 686 800 914 1028114212561370148415981712182619402054216822822396251026240.00E+00

5.00E+06

1.00E+07

1.50E+07

2.00E+07

2.50E+07

3.00E+07

impedance vs time

water MeOH EtOHiso propanol DCM Hexane

Repeatability

10 556 1102 1648 2194 2740 3286 3832 4378 4924 5470 6016 6562 7108 7654 8200 8746 9292 9838 10384109301147612022125680.00E+00

5.00E+06

1.00E+07

1.50E+07

2.00E+07

2.50E+07

3.00E+07

Repeatability - impedance

10 530 1050 1570 2090 2610 3130 3650 4170 4690 5210 5730 6250 6770 7290 7810 8330 8850 9370 9890 1041010930114501197012490

-120

-100

-80

-60

-40

-20

0

Repeatability -phase

Sensitivity

2 20 38 56 74 92 1101281461641822002182362542722903083263443623803984164344524704885065245425605785966140.00E+00

5.00E+06

1.00E+07

1.50E+07

2.00E+07

2.50E+07

3.00E+07

sensitivity

38% 20% 10% 7%

* The percentages stand for relative humidity.** The saturated water vapor pressure at test temperature (23.8 OC) is 2.95 kPa.

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Nanotoxicity Detection Using Stem Cells

www2.le.ac.uk

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Size-dependent Toxicity of Gold Nanoparticles

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Size-dependent Toxicity of Gold Nanoparticles

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Projects in the Mao Lab

• Targeted drug delivery– Reduce drug toxicity by targeting– Control drug release by polymer chemistry

• Nanosensor development– Synthesis nanowires on nanoparticle seeds–Manufacture low-cost nanowire sensors

• Nanotoxicity– Use stem cell technology to detect nanotoxicity– Ultrasmall gold nanoparticles are very toxic!

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Classes of Nanomaterials

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Classes of Nanomaterials

2. Nanowires (1D). One dimension larger than 100 nm.

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Classes of Nanomaterials

3. Thin films (2D). Two dimensions larger than 100 nm.

Graphene (image provided by Max Planck Institute)

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How can we see things on the nanoscale?

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Scanning Electron Microscope

• Use reflected electrons to image small objects.

Pollen grains courtesy of New Scientist AFM cantilever

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Transmission Electron Microscope

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Scanning Tunneling Microscope

Courtesy of the Grill group

Silicon atoms, Courtesy of the Munowitz group

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Atomic Force Microscope

Laser diode

PhotodiodeCantilever

Mirror

Piezotube

Liquid cell

Substrate

• Spatial resolution ~ 1 nm• Force sensitivity ~ 1 pN• Imaging in solution• Roughness, heterogeneity, forces, etc.

Heater

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Nanotechnology Improves Quality of Life

• Biomedical– Targeted drug delivery with fewer side effects– Imaging for early detection– Biomedical coatings to reduce infection

• Materials Science– Stronger and lighter materials– Energy-saving windows and construction materials– Stain-resistant fabrics

• Computers– Smart tablets, phones, watches, etc.– Smaller transistors

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Why do we need nanotechnology for these things?

• Cells are a few microns in size, so nanometer sized objects can move through cell walls, into the cell nucleus.

• Nanoparticles have a very large surface area, making them useful for applications relying on the interface between different materials.

• Electronic components are already less than 100 nm; increasing their performance will rely on working at smaller length scales.

• The physical properties of materials at small length scales is very different than in bulk.

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HOW DO WE MAKE NANOMATERIALS?

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Top-down Approach

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Lithography

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Bottom-up Approach

• The object is constructed from molecules by intermolecular interactions (example: biomembrane).

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Self-assembly

Courtesy of Science Direct

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Combined Bottom-up and Top-down Nanotechnology

• Electrochemical nanowire sensor (the Mao lab)

Figure 8. Proposed micro-electrodes for the electrochemical deposition of TTF-based nanorods as interconnects.

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HOW DO THINGS CHANGE AT THE NANOSCALE?

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Mechanical Properties Change

Carbon fiber vs. carbon nanotube

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Electronic Properties Change

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Optical Properties Change

Gold nanoparticlesCourtesy of nanotech.blogspot.com

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Magnetic Properties Change

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Dynamic Properties Change

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Why does surface area matter for nanotechnology?

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Why does surface area matter for nanotechnology?

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CARBON NANOMATERIALS

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sp3 Hybridized Carbon Crystals

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sp2 Hybridized Carbon Crystals

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Comparison between sp3 and sp2 C

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sp2 Hybridized C Nanomaterials

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Carbon Nanotubes

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Structure vs. Properties

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sp2 Hybridized C Nanomaterials

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Carbon Nanostructures

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Properties of Carbon Nanotubes

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Biomedical Applications of Carbon Nanotubes

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Biomedical Applications for Nanoparticles

• Drug delivery.• Imaging and diagnostics.• Theranostics.

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TYPES OF NANOPARTICLES

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Iron Oxide Magnetic Nanoparticles

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CdSe Quantum Dots

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Gold Nanoparticles

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Dendrimers

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Liposomes

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NANOPARTICLE SYNTHESIS

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Colloidal Chemistry

Gold nanoparticle by citrate reduction

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Gold Nanoparticle Synthesis

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Hydrothermal Synthesis

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Microemulsion

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Homework 1 Assignment1. Use a table to list three types of nanoparticles, typical size range studied/used, being

used in clinical trial or not, if yes, list the year of its first clinical trial, being used in commercial products or not, if yes, list the year of the first product in the market, and list three potential applications.

2. Suppose that a cell (assume to be a sphere of 10 micrometer in diameter) contains 1,000,000 iron oxide nanoparticles of diameter 10 nm. What fraction of the total mass (cell plus nanoparticles) is provided by the nanoparticles? Assume that the cell density is 1 g/cm3 and the iron oxide density is 5 g/cm3.

3. Thermogravimetric analysis (TGA) is a nanomaterials characterization method to determine chemical composition. It works by measuring weight loss after burning off the organic drug part of an inorganic nanoparticle/drug conjugate. In one study, a 4 nm diameter gold nanoparticle is protected by a monolayer of a thiol of molecular weight 150 g/mol before it is conjugated to a drug of molecular weight of 366 g/mol. TGA measurement of weight loss of the thiol-protected gold nanoparticle is 93.85wt% (gold):6:15wt%(thiol). TGA measurement of weight loss of the thiol-protected gold nanoparticle conjugated to the drug is 100wt%(gold):6.6wt%(thiol):8.3wt%(drug). (1) Calculate the molecular weight of the gold nanoparticle in g/mol. (1) Calculate the number of thiol molecules attached to one gold nanoparticle. (2) Calculate the number of drug molecules attached to one gold nanoparticle.