1. Impact Factor 6.378
Literature Meeting
M. Ehsan
Bionano Chemistry Lab

2. Introduction
Supramolecular Polymer
A supramolecular polymer is a polymer whose monomer repeat units are
held together by noncovalent bonds.
Coordination
π-π interactions
 hydrogen bonding
Quadruple hydrogen bonds
Hydrogen Bond Quadruple AngewChemIntEd 1998 v37 p75
EurJOrgChem page2565 year1998

3. • Peptide-amphiphiles are attractive candidate biomaterials for
bio-nanotechnology and tissue engineering
• applications ranging from controlled gene and drug release,
• skin care,
• nanofabrication,
• biomineralization,
• membrane protein stabilization
• 3D cell culture and tissue engineering.

4. Synthetic Strategy
Fig. 1 Schematic representation of the chemical structures of pyrenei midazolium labeled peptide and viologen
functionalised PNIPAAm and the formation of a ternary complex with CB[8].

5.  Cucurbiturils are macrocyclic molecules made of glycoluril (=C4H2N4O2)
monomers linked by methylene bridges.
 drug delivery, asymmetric synthesis, molecular switching, and dye tuning
 Cucurbit[8]uril (CB[8]) ternary complex system offers strong binding of
two complementary motifs (binding constants Keq = 1012 M-2) in water
 The CB[8] is an attractive choice for building stable, modular
supramolecular structures in an aqueous environment via a non-covalent
route.
Acta Crystallogr B, 1984, 382-387
Cucurbituril gyroscope AngewChemInt
Ed 2002 v41 p275

6. Supramolecular Polymeric Peptide Vesicle Formation
Fig. 2 Schematic representation of the temperature induced formation of a supramolecular
polymeric peptide vesicle.

8. Thermoresponsive Behaviour
Fig. Thermoresponsive behaviour of 1 + 2 with and without CB[8]
(0.05 mM).

9. TEM micrographs of supramolecular vesicles at 37 oC (solution concentration = 0.05
mM).
Particle size distributions of supramolecular vesicles at 37 oC.

10. Critical Aggregation Concentration (CAC)
Figure : Determination of the CAC of the supramolecular vesicles in (a) deionised water and
(b) 1X phosphate buffer saline (PBS) solution containing 1% fetal bovine serum (FBS) at pH
7.4

11. Basic fibroblast growth factor (bFGF)
 Basic fibroblast growth factor is a mitogenic cytokine protein
 Regulates many aspects of cellular activity, such as cell migration and
extracellular matrix metabolism.
 bFGF degrades rapidly when the external environment is above 40 oC or
when the pH is less than 5,
 Heparin is required to stabilise the protein and to
preserve its bioactivity
 The efficacy of bFGF in vivo is also limited
its short lifetime and
susceptibility to enzymatic degradation
http://en.wikipedia.org/wiki/Basic_fibroblast_growth_factor

12. • Various approaches have been proposed for the stabilization of bFGF.
• These include the
 Chemical modification techniques,
 Encapsulation in gels and
 Powder formulation.
• Vesicles are highly attractive carriers for proteins due to their hydrophilic
interior.
• minimises the risk of protein denaturation as it does not expose
the protein to extremes in temperatures or organic solvents

13. Encapsulation Effect on the Immunoreactivity of bFGF
Fig. 4 (a) Assessment of immunoreactive bFGF in vesicles after encapsulation
at various times

14. Bioactivity of bFGF
(b) Bioactivity of bFGF following storage in vesicles
after encapsulation at various times.
Effect of freeze-thaw denaturing conditions as compared to
heparin treatment on the bioactivity of bFGF encapsulated in the
vesicles.

15. Release Behavior
Figure : bFGF release (37 oC) from the vesicles made from the ternary complexes.

16. Conclusion
• Protein-friendly nature of the vesicles was demonstrated
by encapsulating bioactive bFGF into the supramolecular
nanocarriers without the use of stabilising agents
• The supramolecular vesicles could potentially be used as
injectable carriers for the release of bioactive cytokines for
tissue repair and other related applications