Prevention of bacterial adhesion onto electrospun fibroporous poly(carbonate) urethane membrane by embedding Graphene oxide Sudhin T. a,b, Maya N c., Vignesh M. a, Ramesh P.* aDepartment of Biotechnology, Indian Institute of Technology Madras, Bhupath & Jyoti Mehta school of biosciences, Chennai, 600036, T.N., ,India bPolymer Processing Laboratory, Sree Chitra Tirunal Institute for Medical Sciences and Technology, BMT Wing, Trivandrum, 695012, Kerala, India cDepartment of Microbial Technology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, BMT Wing, Trivandrum, 695012, Kerala, India
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Introduction
Objective
Biomaterial related infection affects millions of people worldwide, in the scenario of implantation these attract lots of bacteria which adhere to the device surface, colonize and form biofilm1. Thus infecting the surrounding healthy area leading to recalcitration or removal of the device which in many cases may not be feasible. Solution to this problem lies in the development of coatings and surface engineered materials. With this intent, hydrophobicity, morphology and topography of surface embedded GO (graphene oxide) membrane (GOPCU) has been exploited as a new approach for the development of bacterial anti-adhesive surfaces. In our study PCU(Polycarbonate Urethane) which is widely used as an implantable biomaterial has been selected. It was electrospun and GO was electrosprayed for surface modification and tested against Gram +ive bacteria Staphylococcus aureus (SA) and Gram –ve Psuedomonas aeruginosa (PA).
•Use of GO nanosheets to engineer surface property of fibroporous PCU membrane . •Prevention of bacterial adhesion on these surface engineered implantable biomaterial.
Materials and methods PCU (Grade Carbothane). GO was synthesized by an improved oxidation method2 using graphite flakes. Solutions for electrospinning was prepared by mixing PCU in DMF/THF (1:1) followed by electrospraying GO dispersed in DMF. Electrospun fibroporous membranes of PCU and GOPCU surface engineered membrane were characterized Morphology (SEM) Contact angle Confocal Raman spectra and Mapping In vitro bacterial adhesion test
Results Contact Angle
Raman Spectra and Mapping PCU
GOPCU
GO flakes PCU membrane Figure1: Contact angle of PCU 121.9±1.5° & GOPCU 92.8±4.2°
SEM
Figure2: Raman spectra and spectral mapping of GO on GOPCU membrane
PCU-SA
PCU-PA
In-vitro Bacterial adhesion study S.aureus adhesion
P.aeruginosa adhesion
5.00E+06 3.00E+07
GOPCU
GOPCU-SA
GOPCU-PA
3.00E+06
PCU
2.00E+06
GO embedded PCU
1.00E+06 0.00E+00
CFU/cm2
CFU/cm2
4.00E+06
2.00E+07
PCU
1.00E+07
GO embedded PCU
0.00E+00 Exp1
Exp2
Exp3
Membranes
Exp1
Exp2
Exp3
Membranes
Figure4: In vitro Bacterial adhesion test CFU/cm2 vs membrane plot, showing 85% reduction against SA and 64% reduction against PA adhesion to GOPCU
Figure3: SEM micrograph of bare membranes and after exposed to bacterial culture for 24h
Discussion and Conclusion GO embedded on electrospun PCU membrane formed a thin film like covering over the surface. Contact angle(fig.1) shifted by a margin of ~30° bringing the surface engineered membrane closer to the hydrophilic region . Raman Mapping using raman spectral peak of GO and PCU showed good GO distribution over the PCU membrane. GOPCU membrane was found to be efficient in reducing bacterial adhesion against both Gram +ve SA and Gram -ve PA. Surface embedded with GO reduced the bacterial adhesion by 85% in case of SA and by 64% against PA as seen in fig.3 and fig.4. Thus surface modification has been successfully adopted to alter the bacterial attachment to biomaterial surface.
Acknowledgements One of the authors Sudhin Thampi acknowledges IITM for the research fellowship. The authors are also thankful to Director SCTIMST for providing laboratory facilities to complete this work.
References 1. Busscher, Henk J., Henny C. van der Mei, Guruprakash Subbiahdoss, Paul C. Jutte, Jan JAM van den Dungen, Sebastian AJ Zaat, Marcus J. Schultz, and David W. Grainger. Science translational medicine, 2012, 153, 1-10. 2. Marcano, D. C.; Kosynkin, D. V; Berlin, J. M.; Sinitskii, A.; Sun, Z.; Slesarev, A.; Alemany, L. B.; Lu W. ; Tour J. M. ACS nano, 2010, 4, 4806–14.
