The document discusses research at the Liu Nanobionics Lab, which focuses on biomaterials, tissue engineering, and nanotechnology. The lab aims to address tissue damage from disease or injury by developing regenerative approaches rather than just replacement. This includes designing scaffolds, surface modifications, and cell encapsulation techniques to facilitate tissue regeneration. The goal is to shift from static tissue replacement to stimulating the body's natural healing abilities.

1. Liu Nanobionics Lab
Biomaterials
Tissue Engineering
Nanotechnology

2. Biomaterials
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Biomaterials encompasses aspects of
medicine, biology, chemistry,
engineering and materials science.
Biomaterials are : “Non-viable
materials used in a medical devices
intended to interact with biological
systems” [D.F. Williams, 1987]

3. Human Tissue Damage
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Disease (e.g cancer, infection, degenerative
diseases).
Trauma (e.g accidental, surgery).
Congenital abnormalities (e.g birth defects).
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Current clinical treatment based on:
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Grafts and Transplants
Artificial Biomaterials

4. Tissue loss as a result of injury or
disease, provides reduced quality
of life for many at significant
socioeconomic cost.
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Thus a shift is needed from tissue
replacement to tissue regeneration by
stimulation the body’s natural
regenerative mechanisms.

5. Biomaterials: Examples
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Joint replacements
Bone plates
Bone cement
Hip Joint
Artificial ligaments
and tendons
Dental implants for
tooth fixation
Blood vessel
prostheses
Heart valves
Skin repair devices
Cochlear
replacements
Contact lenses
Heart valve
Knee joint
Hip joint
Skin

6. Biomaterials

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Prostheses have significantly
improved the quality of life ( Joint
replacement, Cartilage meniscal
repair, Large diameter blood vessels,
dental)
However, incompatibility due to
elastic mismatch leads to
biomaterials failure.

7. Tissue Engineering

National Science Foundation first defined
tissue engineering in 1987 as “ an
interdisciplinary field that applies the
principles of engineering and the life
sciences towards the development of
biological substitutes that restore,
maintain or improve tissue function”

8. Tissue engineering

Potential advantages:
 unlimited
supply
 no rejection issues
 cost-effective

9. Tissue Engineering
Expand number in culture
Remove cells from the
body.
Seed onto an appropriate
scaffold with suitable growth
factors and cytokines
Re-implant engineered
tissue repair damaged
site
Place into culture

11.  SCAFFOLDS

17. PLGA Scaffold

18. Synthetic polymers
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More controllable from a
compositional and materials
processing viewpoint.
Scaffold architecture are widely
recognized as important parameters
when designing a scaffold
They may not be recognized by cells
due to the absence of biological
signals.

19. Natural polymers
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Natural materials are readily
recognized by cells.
Interactions between cells and
biological materials are catalysts to
many critical functions in tissues
These materials have poor
mechanical properties.

21. Tissue engineering scaffold:
controlled architecture
Featured with:
Pre-defined channels;
with highly porous
structured matrix;
With suitable chemistry
for tissue growth –
Collagen or HA
No toxic solvent involved,
it offers a strong potential
to integrate cells/growth
factors with the scaffold
fabrication process.

22. Architecture of Hard Tissue
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Staggered mineral platelets
(hydroxyapataite) embedded in a
collagen matrix
Arrangement of platelets in
preferred orientations makes
biocomposites intrinsically
anisotropic
Under an applied tensile stress,
the mineral platelets carry most
of the tensile load
Protein matrix transfers the load
between mineral crystals via
shear

23. Tissue engineering scaffold:
Electrospinning
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This process involves the ejection of a charged polymer fluid onto an oppositely
charged surface.
Multiple polymers can be combined
Control over fiber diameter and scaffold architecture

24. Printing Techniques for Tissue Engineering

25. Techniques to study scaffolds:
Scanning Probe Microscopy
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Atomic Force
Microscopy :Surface
irregularities
Scanning Tunneling
Microscopy:
Conducting Surfaces
Adhesion Force
Microscopy:
Functionalised tips

26. Surface Modification of Biomaterials

27. Enhanced intrinsic biomechanical properties of osteoblastic
mineralized tissue on roughened titanium surface
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Nano-indentation
Acid-etched vs. Machined
surfaces
culturing osteoblasts on
rougher titanium surfaces
enhances hardness and
elastic modulus of the
mineralized tissue

28. Protecting Bionic Implants

29. Immunoisolation for Cell-encapsulation
therapy
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Liver Dysfunction: Encapsulation of
Hepatic Cells
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Pancreas Dysfunction: Encapsulation of
Islets of Langerham
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Disorders of the CNS: Parkinson’s,
Alzheimer’s
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Pre-requisites for cell encapsulation
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continued and optimal tissue/cell
supply
maintenance of cell viability and
function
successful prevention of immune
rejection
Nanoporous Silicone-based biocapsules
serves as Artificial Pancreas(Desai et
al. 2001)
What are the drawbacks of such an
artificial pancreas?

30. Nanoengineering Bio-analogous
Structures
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Bone-cartilage
composite ?
Muscle ?
Brain-machine
Interface ?

31. An Ink-Jet Printer for Tissue Engineering?