Transcript Polyglycolide/lactides/caprolactone homo and copolymers

Our Facilities
We have modern laboratories which are equipped to
meet the requirements of a wide range of
experimental research. (But, we still lack a lot !!)
- Polymer synthesis laboratory
- Polymer characterization laboratory
- Cell-culture laboratory
- Imaging laboratory
- Nanofiltration
Our Research Topics
Involving Nanotechnology
• Biomaterials/tissue eng
• Drug/DNA/RNA delivery
• Nanomedicine
• Biosensors
• Biochips
• Imaging
• Biocatalyst Development
• Bioseparations (with emphasis on Nanotechniques)
Biomaterials & Tissue engineering
Microporous Biodegradable
Electruspun PCL Scaffolds
Microporous Biodegradable
PLLA-CL Scaffolds
prepared in supercritical CO2
NANOFIBROUS MATERIALS
By Electrospinning
Electrospinning
is a unique method
that produces
polymeric nanofibers
with diameter in the
range of nano to
a few microns
using electrically
driven jet of
polymer
solutions/
melts
Composites for Hard Tissue Repair
Poly(DL-Lactide/ε-caprolactone) with nano-size TCP
Aim: To prepare a hard
H3PO4
tissue filling material that is
biodegradable, easily
Ca(OH)2
applied
precipitate
HEAT + NH4OH
centrifugation
Average particle size;
Gel form: 300 nm
Dry form: 10 nm
TCP gel
Dring and Sintering
DRUG/DNA/RNA DELIVERY
At 28ºC
Gene Expression
Efficiency: 50%
Imaging at Nanoscale
SCANNING PROBE MICROSCOPIES
•
•
•
•
Scanning Tunnel Microscopy
Atomic Force Microscopy
SPR Microscopy
Imaging Ellipsometry
Scanning Tunnelling Microscopy
STM
Gerd Binnig & Heinrich Rohrer
NOBEL PRIZE in 1986
Binning and Rohrer, IBM
ONLY Conducting surfaces and
researcher’s in Switzerland
molecular
monolayers
described
the STM in 1981. It is
essentially a superfine stylus that
5 µHigh resolution
straightforward
sweeps over a surface like a blind
person’s walking stick. The stylus is
few atom widths away and it has a
molecularly or perhaps atomically
fine tip.
Atomic Force Microscopy (AFM)
The AFM head employs an
optical detection system in
which the tip is attached to
the underside of a reflective
cantilever. A diode laser is
focused onto the back of a
reflective cantilever.
As the tip scans the surface of
the sample, the laser beam is
deflected off the attached
cantilever. And the
photodetector measures the
difference in light intensities
between the upper and lower
photodetectors, and then
converts to voltage.
Contact mode
ATOMIC FORCE MICROSCOPY (AFM)
ATOMIC FORCE MICROSCOPY (AFM)
Erythrocytes
DNA
Antibody
Cromosome
SPR Microscope
SPR
CCD Camera
L4
PC/Framegrabber
Stages
Stage Controller
2Θ
(%)
Flow
Cell
100
Θ
L3
Prism
Filter
L2
L1
Polarizer
l/4 Waveplate
HeNe
Laser,
1.5 mW
Reflection Intensity
Substrate
0
I
II
Angle of Monitoring
Following: W. Knoll,Colloid Polym. Sci. 1988, 109, 244
Imaging Ellipsometry
Dextran on silicone
Polarizer
Analyzer
Objective
Compensator
Sample (e.g. film)
Substrate
Dye monolayer
Patterned surface
FORCE MEASUREMENTS
by using Modified AFM Tips
BIOSENSORS
ANALYTE
SIGNAL
BIORECEPTOR
TRANSDUCER
Enzyme
Antibody
Receptor
DNA
Electrochemical
Optical
Piezoelectric
The bioreceptor is a biomolecule that recognizes the target
analyte. The transducer converts the recognition event
into a measurable signal.
QUARTZ CRYSTAL MICROBALANCE
Quartz crystal plate
Contact
Au electrodes
UNIVERSAL SENSORS Inc.
ATOMIC FORCE MICROSCOPY
As molecular sensors
ATOMIC FORCE MICROSCOPY
As molecular sensors
Representative
fluorescence microscopy
images: (A) and (B)
before ssDNA
immobilization; (C) and
(D) carrying the
immobilized ligand
ssDNA
MAGNETICALLY LOADED
NANOPARTICLES
Nanoparticles take on special properties
because of their small size.
Nanoparticles can be use as carriers or
labels with a variety of markers,
transported through various media, and
interfaced both in vivo and in vitro.
Nanoparticle technology over the last
decade plays an important role in the
diagnosis and treatment of cancer.
Biomedical Applications
Early disease detection
As reporter platforms
Imaging
As contrast enhancing agents
Drug delivery
As a vehicle
MAGNETIC NANOPARTICLES
Magnetic and Superparamagnetic
Particles
– Colloid size: 1-5 µm
– Magnetite (Fe3O4), Maghemite (γ- Fe2O3)
Colloidal Magnetic Particles
– Colloid size: 50-500 nm
– Ferrofluids
BIOCHIPS
Thousands of genes and their products (i.e., proteins) in a
given living organism function in a complicated and
orchestrated way that creates the mystery of life
Traditional methods in
molecular biology generally
work on a "one gene in one experiment" basis, which
means that the throughput is very limited and the "whole
picture" of gene function is hard to obtain
Biochips, or also so-called “micro arrays”
are “Labs on Chips” and allows simultaneous analysis
of multiple samples
DNA-CHIPS
PROTEIN-CHIPS
SURFACE PLASMON RESONANCE
Microarray-based studies of
Protein-DNA Interactions Using SPR
dsDNAs with
Different sequences
DNA binding
proteins
Stealth
printhead/pin
Substrate
Substrate
platform
Microtiter
plate
• Protein binding shifts SPR minimum to a
higher angle.
• Adsorption and desorption monitored by
tracking SPR angle changes.
• SPR response can be converted to a surface
coverage.
Proteins in buffer
dsDNA array
Sensing surface
 % Reflectivity
Vacuum
manifold
Water
bath
Sonicator
Blotter
Adsorption
Adsorption
Time
Desorption
Selection and characterization of peptides specific to
Platinum surfaces by phage display and preparation of
their light sensitive nano-hybrid forms
 Identification of peptide sequences specific to inorganics (Platinum metal) via phage
display and physical and chemical characterization of selected peptides
 Preparation of nanostructures consisting of Pt/putative peptide/light sensitive molecule
(azobenzene)
Ligand for
any target
Light-sensitive
molecule
Peptide
Pt Substrate
N
N
N
N
360 nm
N
N
470 nm
Control of ligand-target interaction
N
N
I. Peptide selection via phage display
Characterization of selected peptides
Statistical analysis
Alignment (Clustal W)
Charge, (http://us.expasy.org/tools/pi),
Hydrophilicity
Fluorescence microscopy
Cross-specificity with powders and arrays
Binding characteristics with QCM, SPR
SD152
PTSTGQA
b) Coupling of peptide to azobenzene molecule
Characterization:
Functional Grup analysis (FTIR, 1H-NMR,
13C-
NMR)
Ninhydrin assay,
Absorption behaviour,
Binding study with QCM ( ka, kd)
Contact angle, elipsometer, AFM on Platinum
surfaces
-Δf (Hz)

time (s)
GENE THERAPY
AIM: To avoid restenosis by Gene Therapy
Proliferation of smooth
muscle cells are stopped by
blocking the MMP-2
enzyme.
For this purpose, inhibitor
gene is transfected to the
smooth muscle cells.
100 µl (1mg/ml) polymer
pH 5.95
10 g plasmid in NaCI
60x 103 smc/ well
GENE EXPRESSION OF SMOOTH
MUSCLE CELLS
ea
b
f
SMC’s transfected with Poly(NIPA-co-MAH)/plasmid
DNA complex (e) light microscope image (f)
Fluorescence microscope image.