The problem In severe burn injuries the skin is damaged

and the first defense against pathogens is

lost. Because of this, bacteria can easily

access deeper parts of the skin, which

provide a suitable habitat for bacterial

growth. The most common pathogens that

cause problems are Staphylococcus aureus

and Pseudomonas aeruginosa. If an

infection is suspected, wound swabs must be

taken to diagnose the pathogens. However,

antibiotics are often used preventively to fight

infections. Also, the treatment of burn

wounds is labor intensive, since the

bandages must be refreshed daily.

Therefore, we designed a smart bandage

which does not require daily refreshment or

treatment with antibiotics, but detects

pathogens and secretes Infection Preventing

Molecules (IPMs) upon detection.

Our Chassis

We introduced Lactococcus lactis in the

competition as a chassis because:

• It is known to be non-pathogenic

• It is a food grade bacterium (e.g.: cheese)

• It produces anti-microbial molecules

• There is no spore formation

This makes it a perfect bacterium for medical

purposes.

Detection Firstly, the pathogens are

detected by their quorum

sensing molecules, namely

AHLs (P. aeruginosa) and

AIPs (S. aureus). After detection the

secretion system is activated. Thereby, the

risk of antibiotic resistance is decreased.

1 Mark, B.L. et al. (2001). J. Biol. Chem. 276: 10330–10337

2 García-Contreras, R. et al. (2013) Appl. Environm. Microbiol. 79: 6840–6846

3 Papaioannou, E., et al. (2013) Microbiol. Mol. Biol. Rev. 77: 73–111

4 Kim, M.H. et al. (2005. PNAS 102

5 Dong, Y.H. et al. (2000. PNAS 97: 3526-3531

6 Wiedemann, I. (2001). J. Biol. Chem. 276: 1772-1779

LactoAid detects quorum

sensing molecules from

S. aureus and P. aeruginosa

and secretes the IPMs DspB,

AiiA and Nisin to prevent

infections in burn wounds.

Secretion of IPMs In response to detection, L. lactis will

produce three IPMs:

DspB degrades Biofilms 1

AiiA disrupts P. aeruginosa

quorum sensing 2-5

Nisin kills S. aureus 6

7 Boonmee, Mallika, et al. Biochemical Engineering Journal 14.2 (2003): 127-135

8 Shimizu, Hiroshi, et al. Applied and environmental microbiology 65.7 (1999):3134-

3141

9 Tong, Jane, and John L. Anderson. Biophysical journal 70.3 (1996): 1505-1513

10 Fischer, Hannes, et al. Protein Science 13.10 (2004): 2825-2828

Toolbox Since we introduced a new chassis for the

competition, a toolbox was designed which

makes the use of Lactococcus lactis easier

in the future. This toolbox consists of: a

vector, a set of constitutive promoters,

several genes from the nisin operon, and a

suitable fluorescent marker.

From Bacterium to Bandage To incorporate the bacterium in a safe way,

we enclosed it in a bandage consisting of

three layers:

• The top layer is transparent, hydrophobic

and permeable to gases.

• The middle layer of polyacrylamide

contains L. lactis.

• The bottom layer allows diffusion of IPMs

and quorum sensing molecules, while

isolating the wound from the bandage.

Results

Left: L. lactis expressing GFP showing

growth in the polyacrylamide gel. Right:

Polyacrylamide gel with nisin-secreting L.

lactis in a plate with a nisin-sensitive strain.

The zone of inhibition confirms that nisin

diffuses through the gel and kills bacteria.

Modelling

The dynamic model was discretized into

lattices each containing differential equations

for growth of bacteria and both diffusion and

production of molecules. 9-12

Six designs were

modelled to find

the best one.

Best design: Nisin diffuses out within 24

minutes, AiiA and DspB within 30 minutes.

Regulation and Public awareness

According to the Dutch Commission for

Genetic Modification LactoAid is a medical

product, which requires elaborate testing but

can be introduced in the market.

We increased awareness of our product and

synthetic biology on a number of events,

such as Discovery Festival and a TEDx event

and by educating high school students.

iGEM Groningen presents

LactoAid The Smart Bandage

AiiA DspB

DspB

A

B

D C

B

A

A

B

C

D

Team Members

1. Rick Elbert

2. Lisa Hielkema

3. Chandhuru

Jagadeesan

4. Anna Lauxen

5. Thomas Meijer

6. Sandra Mous

7. Aakanksha

Saraf

8. Otto Schepers

9. Oscar Smits

10. Andries de Vries

11. Lianne Wieske

12. Freek de Wijs

Supervisors

13. Ruud Detert

Oude Weme

14. Bayu Jayawardhana

15. Oscar Kuipers

16. Renske

van Raaphorst

17. Jan-Willem

Veening 1

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