Download TMS Meeting, 3/04

Nanotechnology –
The Enabling Tool for the 21st Century
Jackie Y. Ying
Institute of Bioengineering and Nanotechnology
Agency for Science, Technology and Research
Singapore
www.ibn.a-star.edu.sg
Grand Challenges for the 21st Century
14 Grand Challenges in Engineering to Impact
Sustainability, Health, Vulnerability, and Joy of Living
www.engineeringchallenges.com
National Academy of Engineering, U.S.A.
• Engineering Better Medicine → Nanomedicine
• Early Diagnosis of Diseases → Nanodevices
• Sequestration of Green House Gases → Nanocatalysts
• Making Solar Energy Economical → Nanomaterials
Stimuli-Responsive Drug Delivery Systems
Encapsulated
substrate
Encapsulated
substrate
Substrate
release
pH
temperature
time
hydrolysis
Polymer
degradation
Substrate
release
Hydrogel particle
Conventional Release Mechanism
• Constant or exponential release over time
• Responsive to pH or temperature change
Need for Stimuli-Responsive Drug Delivery
• Insulin delivery to patients with diabetes mellitus
– Insulin release in response to glucose concentration
– Mimic physiological secretion
– Eliminate the need for patient blood sugar monitoring
Polymer swelling
Stimuli-Responsive Drug Delivery Systems
• Insulin delivery to patients with diabetes mellitus
– Insulin release in response to glucose concentration
– Mimic physiological secretion
– Eliminate the need for patient blood sugar monitoring
• Glucose-sensitive polymers
– Tetravalent glucose-binding protein (e.g. Con A)
– Polymer containing glucosyl groups (e.g. Dextran)
1. Free glucose
diffuses into matrix
2. Free glucose competes with
polymeric glucose
3. Crosslinking protein releases polymer chains
4. Matrix degrades allowing substrate release
Tailoring of Insulin Delivery Nanoparticles
Glucose-sensitive polymers as insulin carrier
Protect insulin to enable oral or nasal delivery
Degrade only at high blood glucose concentration
Cumulative Insulin Release
120%
Formulation
of polymer as
[glucose] (mg/dl)
400
nanoparticles
100%
Small enough
to escape macrophage
80%
digestion
60%
Enhance systemic absorption
100 and
40%
50
bioavailability
20%
0%
0
50
100
150
Time (min)
Dextran 70K
200 nm
200
250
Cumulative Dex-Insulin Release
Insulin released upon polymer degradation
120%
[glucose] (mg/dl)
100%
400
80%
60%
40%
20%
50, 100
0%
0
50
100
150
Time
Time(min)
(min)
Dextran-Insulin
200
250
MicroKit for Infectious Disease Diagnosis
Challenge – Rapid, accurate diagnosis of infectious diseases (Market: $2.1B)
Solution – A fully integrated, portable system: MicroKit
• Disposable polymer cartridges with self-contained
reagents
• Automated sample processing
→ Rapid isolation of purified RNA and/or DNA from
tissues and body fluids
• Automated microfluidics and RT-PCR detection
Impact – Early detection and subtyping of influenza
(H1N1) and other viral infections in ~ 2 hours
• Spinoff: SG Molecular Diagnostics
• New platform for the simultaneous diagnosis of
multiple samples for up to 25 diseases in 1 hour
• Focus on diagnosis of bacterial infection
→ Critical in treatment of “superbugs”
Lab on a Chip (2010)
Carbon Dioxide Utilization and Conversion
Challenge – 5500 MT/year of carbon emissions causing global warming
Solution ‒ Utilize CO2 as a cheap, sustainable C1 feedstock
Methanol CO
CO2
R-C≡C-COOH R-C═C-COOH
Green Energy: Methanol (Market: 70 MT/year)
• Highly effective carbene organocatalyst
N
N
→ Ambient reaction with > 90% yield
→ Oxygen-tolerant, metal-free catalyst
→ Heterogeneous polycarbene catalyst allows for ease of recycling
Green Synthesis of Pharmaceuticals and Chemicals
• Propiolic acid, acrylic acid (US Market: 1.3 MT/year)
Impact – Environmental protection against global warming
– Green synthesis of chemicals
Advanced Materials for Energy Applications
Hollow PtRu
Alloy
Ru/Hollow Pt
Bell-cage Pt-Ru
CdSe@Pt
Core-Shell
Nat. Mater. (2009), J. Am. Chem. Soc. (2010)
PbS–Au
Nanocomposites of metals, semiconductors, oxides
– Unique size effects and synergism between components
– Unprecedented control of microstructures, morphologies
→ Materials with superb activity, selectivity, efficiency
Clean, efficient energy conversion and storage
• Fuel cells
• Solar cells
• Batteries
PtFe–Au
Nanonecklace