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Polymer Chemistries for Cell-Chell Interactions - SynBioNT

"Polymer Chemistries for Cell-Chell

Interactions"

ChellNet and SynBioNT Meeting,

Nottingham, December 21-22 nd 2009

Cameron Alexander

School of Pharmacy, University of Nottingham, University Park,

Nottingham NG7 2RD UK

http://www.nottingham.ac.uk/pharmacy/


Polymers and Information content

• Structures of natural and

synthetic polymers.

• Monomer units (a,i) can be

assembled into defined (b) or

random (ii) sequences.

• Further complexity via

regions of selfcomplementarity

as in t-RNA

(c), or in block-co-polymers

(iii).

• Cross-linking of polymer

chains occurs in both natural

polymers via S-S links in

proteins (d) or in network

polymers (iv).

• Combinations of blocks with

complex architectures can be

found in glycoproteins (e) and

dendrimers (v)


Organisation and self-assembly

• Lengthscales and structures/architectures in synthetic

and natural systems of increasing complexity


Polymers in Pharmacy

Intelligent/Responsive Materials for Biomedical Applications

• What are intelligent materials and why do they

matter?

Examples of intelligent materials in nature

‘Smart’/responsive polymers and biomimicry

• Responsive polymers in biomedicine

Biomedical polymers and clinical needs

Responsive polymer complexes and nanoparticles

• Blurring the boundaries – where synthetic and

natural polymers converge

Controlling biological information transfer with ‘smart’

materials


Polymer switches – biomedical context

Why are these useful in biology and medicine?

• New functional materials (macromolecules and polymers)

required for:

• Biosensors

• Implants / structural biomaterials

• Controlled release materials

– Drug and gene delivery

– Polymer therapeutics

• Tissue engineering

– Biocompatible/biodegradable scaffolds

• Stimuli-responsive materials to change properties in

the dynamic biological environment

• Restore, replace or enhance biological function

• Switch leading to logic operations

• Towards a synthetic cell…..


Polymers in synthetic biology

• Polymer chemistries for cell

recognition

• Binding and release as ‘on-off’

logic operation

• Assembly of polymers into

supramolecular objects –

physical manifestation of

protocell

• Interaction of polymers with

cell-cell communication systems

• Self-assembled polymer ‘cells’

and cross-talk with real cell

communication systems


Responsive polymers and bacterial recognition

Testing the concept - polymers with glyco-ligands

• Can we switch ‘on’ and ‘off’ the signals from glycoligands

to cells (switchable glycocode)?

– Signaling pathways at cell-environment interface

– Specific ligand-receptor interactions

• Glycopolymers with defined ligand moieties to trigger

biological responses

– Optimum size for interaction with cellular organelles

– Multiple functionality

– ‘Soft’ in nature

– Supramolecular conformation / biological mimicking

– Multivalent interactions

• First generation model to probe cell targeting

modalities


Glycopolymers for ‘on-off’ cell

recognition

O NH O NH

O NH O NH

OH

AIBN THF

70 o C 24 h

AIBN THF

70 o C 24 h

*

n

O NH O NH

n

O NH O NH

*

m

OH

m

1- AcGLc DCM

Lewis acid 24 h

2- NaOMe / MeOH

EDC HEPES

pH 4.5 GlcAm

*

*

n m

O NH O N

H

n

O NH O N

H

m

P1

P2

O

H

N

O

HO

O

HO

O

OH

OH

OH

OH

OH

OH

OH

O

OH

O

Pasparakis, G. et al. J. Am. Chem. Soc. 2007, 129, 11014 – 11015


Polymer – E. Coli (MG1655 pGFP) interactions

45 o C

n

m

O NH O N

H

O

HO

O

OH

OH

OH

n

m

O NH O N

H

O

HO

H

N

O

OH OH

OH

25 o C

(white bar: 10μm)

Pasparakis, G. et al. J. Am. Chem. Soc. 2007, 129, 11014 – 11015


Repeat ‘Hide and Reveal’ binding cycles

(Polymer – E. Coli MG1655 pGFP interactions)

P1

P2

45

45

25

Temperature ( o C)

25

(white bar: 10μm)

Pasparakis, G. et al. J. Am. Chem. Soc. 2007, 129, 11014 – 11015


Towards polymer cell ‘cross-talk’…..

• Biocompatible vesicles as long-circulating carriers

• Polymer self-assembly into higher-order structures

• Cell-mimics with hydrophobic ‘cell-wall’ and

glycosylated surfaces

• Potential for cross-talk with biological cells


Responsive glycovesicles

Pasparakis, G. Angew Chem Int Ed. 2008 47 (26), 4847-4850


Responsive vesicles

Polymer M n /

kDa [a] M w

/M

[b]

n

x:y ratio [b] LCST ( o C)

P1 11.2 1.34 10:50 28

P2 15.2 1.11 28:36 28


Vesicle biorecognition

Pasparakis, G. Angew Chem Int Ed. 2008 47 (26), 4847-4850


‘Talking’ to cells with glycopolymers 1

0 0.1 nM 1 nM

0.01 mM

[Glucose]

Pasparakis, G. et al. J. Am. Chem. Soc. 2007, 129, 11014 – 11015

Pasparakis, G. Angew Chem Int Ed. 2008 47 (26), 4847-4850


‘Talking’ to cell-vesicle aggregates 2

Pasparakis, G. Angew Chem Int Ed. 2008, 47 (26), 4847-4850


Specificity of interaction

a) b)

c) d)


Dynamics of interaction

Pasparakis, G. Angew Chem Int Ed. 2008, 47 (26), 4847-4850


Polymer logic operators

• Combination of phase transitions and binding

events to describe logic gates


Polymer INH Gate

• P1- Alizarin Red

interactions at all

four possible input

combinations are

shown in a).

• Fluorescence output

is recorded as

output in b) and

construction of the

INHIBIT truth table

• Pasparakis, G.; et al. Soft Matter 2009, 5, 3839 – 3841.


Polymer AND Gate

• P2-AR-PBA

interactions at all

four possible input

combinations are

shown in a)

• Fluorescence

emission is recorded

as output in b) with

construction of the

AND truth table.

• Pasparakis, G.; et al. Soft Matter 2009, 5, 3839 – 3841.


Polymer Logic and Quorum Sense

• AI-2 and QS-capture

polymers and

polymer QS

scavenging

networks:

• (b) Alizarin Red S

reporter assay for

polymer-boronate

complexation

• (c) polymer

interactions with AI-

2 or boronate

analogues for QS

switching in Vibrio

species

Pasparakis, G.; Gardner, P.; Davis, B.G.; et al unpublished


Vibrio bioluminescence in

presence of polymers

• Vibrio harveyi BB170

in the absence and

presence of PVA (a),

GAL (b) and GEMA

(c). Bioluminescence

curves in the absence

of polymer are shown

in red - insets show

expansions of the

delay time of

luminescence onset.

In (d) optical

densities of

suspensions

containing Vibrio with

and without polymers

are shown.

Pasparakis, G.; Gardner, P.; Davis, B.G.; et al unpublished


Quorum quenching?

• Light production maxima in presence of PVA, GAL and GEMA

polymers for Vibrio harveyi strains BB170 (a) and MM32 (b).

Controls refer to light production in absence of polymers

without (a) and with (b) added AI-2

Pasparakis, G.; Gardner, P.; Davis, B.G.; et al unpublished


A Turing test for CHELLs

(a) Representation of the

classic Turing test with an

intelligent interrogator (i.e.

person, interacting with two

compartments, each

containing either a computer

or a person, the location of

which is unknown to the

interrogator).

(b) Extension of this

interrogator or interaction

between cells and Chemical

cELLs (‘Chell’s) containing

signal-intercepting polymers


Enacting the Turing Test....


Future Directions

• Synthetic Biology needs ‘intelligent’ materials

• New polymer chemistries offer unprecedented control over carrier

vehicle structure and properties

– Easier formulation

– Reduced complexity in regulatory issues

• Truly ‘smart’ in situ diagnostics and therapeutics will soon be made in

the lab – what else can we do with these materials?


Acknowledgements

Dr Wenxin Wang, Dr

George Pasparakis, Aram

Omer Saeed, Dr Ji-Won

Pack, Mahmoud Soliman,

Johannes Magnusson,

Liang He, Felicity Heath,

Sabrina Dey, Driton

Vlasaliu, Racha Cheikh

Al-Ghanami, Samer

Abulateefeh, Dimitra

Nikolaidi,

Xuan Xue, Robyn Fowler,

Mario Ferrugia

University of Nottingham

School of Pharmacy

Professor Kevin Shakesheff

Professor Martyn Davies,

Dr Stephanie Allen

Dr Jon Aylott, Dr Weng Chan, Dr

Felicity Rose, Dr James Ellis, Dr

Martin Garnett

School of Chemistry

Professor Steve Howdle

Institute of Infection and Immunity

Dr Alan Cockayne

University of Nottingham

School of Computer Science and IT

Dr Natalio Krasnogor

University of Oxford

Professor Ben Davis

Paul Gardner

University of Glasgow

Professor Lee Cronin,

Dr Geoff Cooper

University of Padova

Department of Pharmaceutical

Sciences

Professor Paolo Caliceti

Dr Stefano Salmaso,

Dr Sara Bersani

Cardiff University

School of Chemistry

Dr Pete Griffiths

Renuka Nilmini

CHELLNet

University of Manchester

Materials Science

Dr Brian Saunders,

Dr Alberto Saiani

Dr Aline Miller

University of Durham

Department of Chemistry

Professor Neil Cameron

University of Queensland

Dr Kris Thurecht (AIBN)

Prof Andrew Whitaker


Publications

• Polymers in medical applications

Polymer-biopolymer conjugates

Responsive nanoparticles

Chem. Soc. Rev. 2010, 39, 286 - 300

Soft Matter 2009, 5, 3839 - 3841

Chem Commun 2009, 6068 – 6070

J. Mater. Chem 2009 19, 4529 - 4535

Biomacromolecules 2009 10, 822-828

Adv. Mater. 2009 21(18), 1809-1813.

J. Mater. Chem 2009 19, 1608-1615.

J Am Chem Soc 2008 130, 10852 - 10853

Chem Commun 2008 4433-4435

Langmuir 2008 24, 7761-7768.

Angew Chem Int Ed. 2008 47, 4847-4850.

Mol. BioSyst 2008 4, 741 - 745.

Nature Mater. 2008, 7 ,767-768

Biomacromolecules 2008 9, 1170-1178.

J. Control. Release 2008, 132, (3), e48-e50

J. Am. Chem. Soc. 2007, 129 (36), 11014 –

11015.

Chem Commun 2007 4602 – 4604

J. Gene Medicine 2007, 9, (1), 44-54.

Langmuir, 2007, 23, (1), 41-49.

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