10:30 Micro-and Nano-Technologies That Will
Enable the Earliest Detection of the Signatures of Cancer and the Ability to
Provide Rapid and Specific Treatment
Mr. Ed Monachino
It has become clear that cancer is a set of diseases that result from
changes in the genome and the expressed products of the genome. The pathway of
technological opportunity resulting from this fundamental observation can have a
profound impact on the management and prevention of cancer.
The first step in this pathway requires
defining the molecular signatures of cancer. The National Cancer Institute has
launched initiatives, including the Innovative Molecular Analysis Technologies
(IMAT) program supporting research projects to develop and carry out pilot
applications of novel technologies that will enable the molecular analysis of
cancers and their host environments.
NCI is currently looking beyond these near term
goals and establishing programs that will pave the way to improved future
medical care. The NCI is implementing the Unconventional Innovations Program (UIP)
to support high impact, long range technological innovations. The UIP is
focused on the development of technology systems that couple minimally
invasive sensing of cancer signatures in patients with capabilities for
controlled and monitorable intervention specific for these signatures.
Based upon a shared vision for the future of
human health care, NASA and NCI have formed a partnership to jointly research
and develop biomolecular sensors that will revolutionize the practice of
medicine on earth and in space. NCI and NASA are supporting the development of
new minimally invasive technologies to scan the body for the earliest
signatures of emerging disease and support immediate, specific intervention.
These technologies will support a seamless interface between detection,
diagnosis and intervention.
11:00 Nanomolecular Biosensors:
Dr. James R. Baker, Jr., University of Michigan
We are developing nanoscale biosensors and bioactuators for use in
individual health and safety monitoring, in conjunction with external analytic
bioNEMS devices. This involves nanoscale polymer structures less than 20 nm in
diameter as the basis of the sensor/actuators. The structures would be designed
to target into specific cells of an individual and be able to monitor health
issues such as the exposure to radiation or infectious agents. These molecules
would also be able to administer therapeutics in response to the needs of the
individual, and act as actuators to remotely manipulate a person as necessary to
ensure their safety. An example of this latter capability would be to activate
muscle movement causing an unconscious person to walk out of harm's way. In
addition, these nanosensors could be used to develop cellular-based biochips
that would be useful as sensors for the remote detection of life or other
scientific analysis. These studies are performed by a multidisciplinary team,
involving a fusion of disciplines including nanotechnology-based materials
science, bioengineering, bioinformatics and medical sciences. We will use these
different disciplines to converge on the design and manipulation of the
nanosensors, and the development of non-invasive systems to interact with the
sensors through functional MRI or multispectral fluorescence imaging. This
latter task would require the engineering of wearable NEMS systems by engineers
involved in this project while other members of the project team would test the
efficacy of these systems using biologic models, such as experimental animals.
Because of these broad requirements, the research would involve the
multidisciplinary team from the Medical, Engineering and basic science
(LS&A) schools at the University of Michigan, and would train
multidisciplinary scientists at the pre-and postgraduate level.
11:30 Magnetic Resonance Molecular Imaging and
Targeted Drug Delivery with Site-specific Nanoparticles:
Dr. Gregory M. Lanza, Washington University School of Medicine
Angiogenesis plays a central role in cardiovascular disease and tumor
development. a n b 3 -integrin as a marker of angiogenic vessel endothelium. We
have reported the development of a ligand-directed perfluorocarbon nanoparticle
system for molecular imaging of angiogenesis as well as for detection of
intravascular thrombosis or inducible proteins, such as tissue factor, in
vivo with magnetic resonance imaging. These unique lipid encapsulated,
perfluorocarbon nanoparticles (~250nm) incorporate on their surface up to 60,000
Gd-DTPA complexes / nanoparticle to manifest very prominent T1
effects that overcome partial volume dilution effects at clinical resolutions
(1.5 T).
Methods: In this report, paramagnetic molecular
imaging of angiogenesis in vivo and the potential for targeted,
quantifiable drug delivery are demonstrated. In part one, paramagnetic
nanoparticles either covalently complexed with an a n b 3 -integrin specific
ligand (targeted; n=3) or nontargeted (control; n=3) were injected
intravenously (ear vein) in New Zealand rabbits bearing hindleg Vx-2 carcinoma
tumors (~250 mm3). Tumor vasculature was imaged in vivo by
MRI (1.5 T) using a T1-weighted, fat-suppressed, 3-D, fast field
echo sequence. In part two, the antiproliferative effects and dissolution
release of paclitaxel (Taxol) from nanoparticles targeted with a specific
tissue factor (TF) antibody to cell-surface TF proteins on vascular smooth
muscle cells (VSMC) are presented.
Results: Angiogenesis was detected with a n b 3
-targeted nanoparticles in asymmetric regions along the outer tumor capsule
and in neighboring vessels and tissues. a n b 3 -targeted nanoparticles
enhanced 8.17 ± 0.86% of the tumor area vs. 1.65 ± 1.74% (p<0.05) in the
control (nonspecific accumulation). MRI signal from the angiogenic vasculature
increased 69.2 ± 3.4% over baseline. The overall contrast enhancement (CEI)
of targeted tumors was 8-fold greater than controls. Muscle did not enhance
with either targeted or control nanoparticles. Corresponding a n b 3
-expression was confirmed by immunohistochemistry (LM609).
VSMC were treated with either control or
paclitaxel nanoparticles that were targeted specifically to tissue factor
receptors or were co-incubated with without ligand targeting. Tissue factor
targeted paclitaxel-nanoparticles inhibited (p<0.05) VSMC proliferation
where as control or nontargeted paclitaxel nanoparticles had no effect on cell
growth. Fluorine spectroscopy was used to confirm the delivery of
nanoparticles to targeted cells and may be used to estimate delivered
paclitaxel nanoparticle concentrations.
Conclusion: Molecular imaging of angiogenesis,
whether stimulated by vascular disease (i.e., myocardial ischemia,
atherosclerotic plaque development, or peripheral vascular insufficiency),
tumors, wounds or therapy (i.e., pharmacological or gene therapy), may be
detected in vivo with ligand-targeted paramagnetic nanoparticles using
a clinical MRI scanner (1.5 T). Moreover, these nanoparticles present a unique
opportunity to treat this broad range of pathology with a targeted and
noninvasively quantifiable system.
12:00-1:30 Lunch (on your own)
1:30 Novel Implanted Drug Delivery Device
Based on Constrained Diffusion through Microfabricated NanoPORE™ Membranes:
Dr. Frank Martin, iMEDD, Inc.
Top-down microfabrication methods have been used to create
"NanoPORE"membranes with parallel rectangular channels which, in their
smallest aspect, range from 4-50 nm. Diffusion rates of various solutes through
such membranes have been measured. Figure 1 shows the cumulative flux of glucose
through NanoPORE membranes fabricated with channel widths ranging from 7 nm to
27 nm. For the 7 nm and 13 nm membranes, flux rates of glucose from one chamber
to a receiver chamber (which initially had no glucose) conform to zero-order
kinetics. That is, the cumulative movement of glucose through the membrane is
linear with time. This pattern is unexpected since the diffusion gradient is
decaying with time and thus the driving force for diffusion would be expected to
decay as well. At 20 nm and 27 nm, the glucose flux becomes Fickian, that is,
the rate slows in a predictable fashion as the gradient decays.
These data indicate that NanoPORE membranes can be engineered
to control rates of diffusion by adjusting channel width in relation to the size
of solutes. Moreover, when the proper balance is struck, zero-order diffusion
kinetics is possible. This discovery prompted us to develop a prototypical drug
delivery device (called NanoGATE™). The device consists of a
reservoir formed from a cylindrical enclosure capped at both ends with polymer
plugs. The tubing is fitted with a NanoPORE membrane as the only connection
between the internal reservoir of the device and the external medium (Figure 2).
The NanoPORE membrane serves to control release rates of drugs loaded into the
reservoir. We reckoned that the device would be useful for delivering small
molecular weight organic drugs as well as larger peptide- and protein-based
biopharmaceuticals. To test the system we selected bovine albumin (MW 60,000
daltons) as a surrogate of a fairly large protein biopharmaceutical. In vitro
release of 125I-labeled albumin for NanoPORE membranes of two sizes,
13 nm and 26 nm, is shown in Figure 3. The rates in both cases are zero-order.
Interestingly, the rate of albumin diffusion through the 13 nm membrane is
approximately twice that of the 26 nm membrane. Note that in both cases the
rates deviate from those predicted by Fickian diffusion principles. We next
tested the performance of NanoGATE in vivo. Devices fitted with 13 nm membranes
and filled with 0.5 mg of 125I-albumin were implanted subcutaneously
in the backs of 3 rats. The devices were adjusted to have an in vitro output
rate of about 5 g/day and thus were designed to release the albumin for
100 days. The pharmacokinetics of the labeled albumin in blood was measured and
compared to a dose of albumin delivered by a standard subcutaneous bolus
injection. Figure 4 shows the mean values for blood levels over a period of 46
days after implantation. In the case of the NanoGATE implant group, following an
initial period of decline (during the first 9 days), albumin concentration in
the central compartment leveled off for the ensuing 4 weeks. The initial decline
is attributed the equilibration of the radiolabeled albumin appearing in blood
with the albumin pool in the interstitial fluid volume. This equilibration has
been reported to have a half-life of 17 days, which is in line with our results.
In comparison to the standard subcutaneous injection, albumin delivered in the
NanoGATE device was detectable for a substantially longer period. As expected,
when the devices were recovered from experimental animals they were encapsulated
in fibrous capsule, but the NanoPORE membrane itself was free of any cellular or
protein intrusion. The foreign body response did not appear to retard the
bioavailability of the albumin released from the device. Moreover, about half
the labeled albumin was recovered in each NanoGATE device, which conforms to
expectation that half the drug would be released during the 7-week in-life
period.
These results encourage us to believe that delivery of a wide
range of drugs can be regulated by devices fitted with such NanoPORE membranes.
Moreover, since the mechanism of release is attributable to a novel constrained
diffusion mechanism provided by the precise geometry of the NanoPORE membranes,
and no moving parts such as pistons are required, we believe that drugs can
loaded into the device reservoir in a range of physical states including
solutions, and crystalline or micronized suspensions. Such flexibility with
respect to the physical form of encapsulated drugs provides options to
substantially increase the loaded dose and duration of therapy as well as
approached to increase the stability of proteins which are intrinsically
unstable in aqueous solution at body temperature.
2:00 Photonic Nano-Explorers: From Subcellular
Chemical Imaging to Cancer Detection and Therapy:
Dr. Martin A. Philbert, University of Michigan
Live cells exhibit a complex chemistry, which literally determines life,
disease and death. While much has been learned by analytical methods that
destroy the cell, many important aspects (e.g., the role of oxygen and free
radicals) require reliable sensors that are nonperturbative to the cell, both
physically and chemically. This has been achieved with nano-devices called
PEBBLEs (Probes Encapsulated By Biologically Localized Embedding). These are
complex nanoparticles, with biocompatible matrices and with synergistically
active interior components, tailor-made for spectrally, spatially and
temporally resolved chemical imaging. Similar nano-explorers detect cancer
cells (or their vasculature) using tailor-made molecular recognition elements
("molecular targets"). The location is reported via MRI contrast
enhancement. Laser light activates the photodynamic components of the nano-platform,
turning normal oxygen into singlet (killer) oxygen. In the dark these nano-particles
are non-toxic and have a reasonable vascular circulation time.
2:30 Roundtable Discussion: The Clinical
Perspective
Moderated by Dr. Carol A. Dahl, Biospect, Inc.
Dr. Michael Caligiuri, Medical Oncologist, The Ohio State University
Dr. Wolfgang Sadee, Department of Pharmacogenomics, The Ohio State University
3:00 Refreshment Break with Exhibit and Poster
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