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Template to create a scientific poster
Design of Rheologically Consistent Artificial Sputum Medium Hope E. Wolterman, Uranbileg Daalkhaijav, Travis W. Walker School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR 97331 Background Cystic Fibrosis: • Caused by a genetic mutation in the cystic fibrosis transmembrane conductance regulators (CTFR) gene • Affects 70,000 people worldwide, 30,000 in the US • Causes a buildup in the lungs of viscous mucus Pseudomonas aeruginosa is a bacteria commonly found in the pulmonary system of humans. In cystic fibrosis patients, it www.bbc.co.uk. reaches heightened population densities and produces EPS, which causes a resistance to antibiotics. Creating Synthetic CF Sputum The following additives were chosen initially to mix with the ASM at one weight percent and tested • Guar gum (GG) • Xanthan gum (XG) • Sodium alginate (SA) • Locust bean gum (LBG) After xanthan gum was chosen, it was mixed with the other gums and 1 wt% xanthan gum tested. XG turned out to be the best additive when it was by itself. Substance Viscoelastic CF Sputum ASM Guar Gum Locust Bean Gum Xanthan Gum Sodium Alginate XG+GG XG+LBG XG+SA N Y N N N N N N N Conclusion Elastically Dominated Y N Y N Y N Y N Y Constant Frequency Sweep Modulus Y N N N Y N N N N Table 1. Comparison of different properties of CF sputum to various additives. Results Through mixing xanthan gum with ASM, we can now make a gel rheologically consistent to expelled cystic fibrosis sputum. After the objectives were obtained, further research can continue to attempt to understand how P. aeruginosa works and how it moves through the thick, netted mucus. Because of the mucus’ unique structure as a complex fluid, we may also get a glimpse of future ways drugs may be administered into a body and transported through the mucus. www.directindustry.com Acknowledgements Normal Airway Cystic Fibrosis Airway Travis Walker Research Website Treatments: • Gene Therapy • Chest Physiotherapy • Lung Transplantation • Aerosolized Medication www.nhlbi.nih.gov Currently, the best treatment for cystic fibrosis (CF) is through chest physiotherapy. Patients usually take a mucus thinner; then, percussion therapy is performed to loosen the mucus so that it can be expelled as phlegm. To study the infectious bacteria P. aeruginosa, it is grown in artificial sputum medium (ASM), a low viscosity fluid that acts as a food source to the bacteria. Objectives The main purpose of this project was to model the rheological properties of CF sputum by mixing ASM with gums. Making a suitable substitute of CF sputum will help us to: • Grow P. aeruginosa on a synthetic substance more similar to CF sputum than ASM • Take rheological measurements of grown bacteria • Study the microrheology of the mucus to better understand how P. aeruginosa behaves in a CF lung • Perfect the technique of using the rheometer and testing the new sputum substitute (ASM+) to get reliable and repeatable data Creating a substitute, ASM+, will help the lab collect valuable research data without having to use extracted CF sputum for every experiment. a. Strain amplitude sweep b. Frequency sweep c. Flow sweep Figure 1. Rheology of CF sputum, ASM, and ASM+XG (xanthan gum). (a) A strain amplitude sweep shows loss modulus (G’ ; open symbols) and storage modulus (G” ; closed symbols) versus percent strain () (=1/s). (b) A frequency sweep shows loss and storage modulus versus percent frequency () (CF and ASM+XG: = 1%; ASM: = 100%). (c) A flow sweep shows apparent viscosity () versus shear rate (). Rheology Research Group (Summer 2014 I would like to recognize Annika Gabriel for her help with this project. I would also like to thank Pete and Rosalie Johnson, Skip Rochefort, and Travis Walker for allowing me to have this great opportunity. Data from Dawson, Wirtz, and Hanes. J. Biol. Chem. 2003 Future Research Future research concerning the ASM+ will involve two different projects. Determination of the mechanical and electrochemical properties of P. aeruginosa biofilm formation in cystic fibrosis sputum • Exploring the correlation between mechanical changes of the mucosal environment and the release of quorum sensing molecules by P. aeruginosa can lead to better treatment of CF and prevention of secondary infections. • Actively grow bacteria in a double wall couette while taking rheological measurements Cartoon by Uranbileg Daalkhaijav Determination of the strengths of adhesion interactions and the ability for penetration of selectively coated micron spheres with mechanically-relevant synthetic pulmonary mucus • The aim of this project is to explore interactions of various types of particulates with excreted biofluids such as mucus, focusing on the differences in pulmonary mucus for people with CF. Cartoon by Ming Yang