BMES Annual Meeting 2011 10/15/2011Hannah BarberNanofibrous Texturizing for Prevention ofBacterial Infection on Biomedical Implants Hannah Barber1,4, Mehdi Kargar2, John Haught2, Amrinder Nain, Ph.D. 2,3, and Bahareh Behkam, Ph.D. 2,3 Biological Sciences Department1, Mechanical Engineering Department2, School of Biomedical Engineering and Sciences3, Scieneering Program4 Virginia Tech, Blacksburg VA
2 Hannah Barber, MicroN BASE 10/15/11 Introduction- The Biofilm Problem Image courtesy of MedScape.comA biofilm developing around the eyehole of a latex catheter. Thecatheter had been removed from a patient 5 days after insertion.
3 Hannah Barber, MicroN BASE 10/15/11Motivation- Catalyst for a Solution• Current treatment for biofilm-associated infections: ▫ Surgical replacement of the implant; ▫ Long-term antibiotic therapy.• We need NEW treatments because: ▫ Current treatments are expensive; ▫ They compound the antibiotic-resistance problem.
5 Hannah Barber, MicroN BASE 10/15/11Inspiration- Taking a Queue from NatureA B A:The naturally antifouling surface of M. edulis; B: the sub- micron topography of the priostracum of M. edulis. Bers, A. V. and Wahl, M., Biofouling, 2004. 20(1): 43-51. C: The C D Image courtesy of medGadget.com Galapagos shark; D: the micro- topography features of the shark’s skin. Image courtesy of FlickRiver.com
6 Hannah Barber, MicroN BASE 10/15/11Objective- Aspiration for a Design• To investigate and characterize the antifouling properties of varying nanofibrous surface topographies.• We used polystyrene (PS) fibers with diameter 500 nm, spaced 2000 nm apart on PS substrates.
7 Hannah Barber, MicroN BASE 10/15/11STEP Fiber Manufacturing* 200 µm Pseudo-dry spinning 200 µm method, STEP, manufacturing platform used for fabrication of nanofibrous surfaces. *Nain, A. S., et al. Macromolecular Rapid Communications, 2009. 30(16) : 1406-1412.
8 Hannah Barber, MicroN BASE 10/15/11Bacterial Assay • Experimental parameters: ▫ Model organism is Pseudomonas aeruginosa (PAO1 strain) ▫ Culture is presented to samples at OD600 = 0.65 ▫ Incubated at 37°C ▫ Incubated for 16 hours Retention assay with suspended sample substrate.
9 Hannah Barber, MicroN BASE 10/15/11 Imaging- Illuminating the Databare single-layer double-layer 5 μm 5 μm 5 μm ImageJ was used to quantify: 1. Areal density of attached bacteria 2. Areal density of bacterial colonies 3. Cluster size
10 Hannah Barber, MicroN BASE 10/15/11 Results- Understanding the Information Bacterial Attachment 0.05 areal density (bacteria/µm2) 0.045 0.04 0.035 • Change in bacterial attachment: 0.03 0.025 ▫ 59% decrease from bare to single 0.02 0.015 ▫ 62% decrease from bare to double 0.01 0.005 0 bare single double Bacterial Cluster Formation• Change in number of clusters: 10 9 ▫ 17% decrease from bare to single 8 and to double 7 6 number of clusters 5 4• Change in bacteria per cluster: 3 bacteria per cluster ▫ 21% decrease from bare to single 2 1 ▫ 24% decrease from bare to double 0 bare single double
11 Hannah Barber, MicroN BASE 10/15/11 Conclusions and Future Work• We can conclude that both the single-layer and double-layer topographies are capable of decreasing both bacterial attachment and cluster formation.• In the future, our team will study the effects of surface topography on gene expression in pathogenic bacteria.