Skip to main content

Journal for Biophysical Chemistry

Biointerphases Cover Image

Mixed poly (ethylene glycol) and oligo (ethylene glycol) layers on gold as nonfouling surfaces created by backfilling


Backfilling a self-assembled monolayer (SAM) of long poly (ethylene glycol) (PEG) with short PEG is a well-known strategy to improve its potential to resist fouling. Here it is shown, using xray photoelectron spectroscopy, contact angle, and atomic force microscopy, that backfilling PEG thiol with oligo (ethylene glycol) (OEG) terminated alkane thiol molecules results in underbrush formation. The authors also confirm the absence of phase separated arrangement, which is commonly observed with backfilling experiments involving SAMs of short chain alkane thiol with long chain alkane thiol. Furthermore, it was found that OEG addition caused less PEG desorption when compared to alkane thiol. The ability of surface to resist fouling was tested through serum adsorption and bacterial adhesion studies. The authors demonstrate that the mixed monolayer with PEG and OEG is better than PEG at resisting protein adsorption and bacterial adhesion, and conclude that backfilling PEG with OEG resulting in the underbrush formation enhances the ability of PEG to resist fouling.


  1. 1

    D. G. Castner and B. D. Ratner, Surf. Sci. 500, 28 (2002).

    CAS  Article  Google Scholar 

  2. 2

    I. Banerjee, R. C. Pangule, and R. S. Kane, Adv. Mater. 23, 690 (2010).

    Article  Google Scholar 

  3. 3

    K. Sauer, A. K. Camper, G. D. Ehrlich, J. W. Costerton, and D. G. Davies, J. Bacteriology 184, 1140 (2002).

    CAS  Article  Google Scholar 

  4. 4

    S. I. Jeon, J. H. Lee, J. D. Andrade, and P. G. De Gennes, J. Colloid Interface Sci. 142, 149 (1991).

    CAS  Article  Google Scholar 

  5. 5

    S. J. Sofia, V. Premnath, and E.W. Merrill, Macromolecules 31, 5059 (1998).

    CAS  Article  Google Scholar 

  6. 6

    L. D. Unsworth, H. Sheardown, and J. L. Brash, Biomaterials 26, 5927 (2005).

    CAS  Article  Google Scholar 

  7. 7

    L. D. Unsworth, H. Sheardown, and J. L. Brash, Langmuir 24, 1924 (2008).

    CAS  Article  Google Scholar 

  8. 8

    L. D. Unsworth, Z. Tun, H. Sheardown, and J. L. Brash, J. Colloid Interface Sci. 281, 112 (2005).

    CAS  Article  Google Scholar 

  9. 9

    P. Kingshott, J. Wei, D. Bagge-Ravn, N. Gadegaard, and L. Gram, Langmuir 19, 6912 (2003).

    CAS  Article  Google Scholar 

  10. 10

    N. Luo, J. B. Hutchison, K. S. Anseth, and C. N. Bowman, Macromolecules 35, 2487 (2002).

    CAS  Article  Google Scholar 

  11. 11

    P. Kingshott, H. Thissen, and H. J. Griesser, Biomaterials 23, 2043 (2002).

    CAS  Article  Google Scholar 

  12. 12

    W. Taylor and R. A. L. Jones, Langmuir 26, 13954 (2010).

    CAS  Article  Google Scholar 

  13. 13

    S. Minko, S. Patil, V. Datsyuk, F. Simon, K.-J. Eichhorn, M. Motornov, D. Usov, I. Tokarev, and M. Stamm, Langmuir 18, 289 (2002).

    CAS  Article  Google Scholar 

  14. 14

    K. Uchida et al., Biointerphases 2, 126 (2007).

    CAS  Article  Google Scholar 

  15. 15

    K. Uchida, H. Otsuka, M. Kaneko, K. Kataoka, and Y. Nagasaki, Anal. Chem. 77, 1075 (2005).

    CAS  Article  Google Scholar 

  16. 16

    T. Kakiuchi, K. Sato, M. Iida, D. Hobara, S.-I. Imabayashi, and K. Niki, Langmuir 16, 7238 (2000).

    CAS  Article  Google Scholar 

  17. 17

    G. G. Baralia, A.-S. Duwez, B. Nysten, and A. M. Jonas, Langmuir 21, 6825 (2005).

    CAS  Article  Google Scholar 

  18. 18

    T. M. Herne and M. J. Tarlov, J. Am. Chem. Soc. 119, 8916 (1997).

    CAS  Article  Google Scholar 

  19. 19

    S. Brunner et al., Langmuir 15, 6333 (1999).

    CAS  Article  Google Scholar 

  20. 20

    C.-Y. Lee, P. Gong, G. M. Harbers, D. W. Grainger, D. G. Castner, and L. J. Gamble, Anal. Chem. 78, 3316 (2006).

    CAS  Article  Google Scholar 

  21. 21

    L. J. G. Chi Ying Lee, David W. Grainger, and David G. Castner, Biointerphases 1, 11 (2006).

    Article  Google Scholar 

  22. 22

    P. Harder, M. Grunze, R. Dahint, G. M. Whitesides, and P. E. Laibinis, J. Phys. Chem. B 102, 426 (1998).

    CAS  Article  Google Scholar 

  23. 23

    H. Otsuka, Y. Nagasaki, and K. Kataoka, Langmuir 20, 11285 (2004).

    CAS  Article  Google Scholar 

  24. 24

    D. G. Castner, K. Hinds, and D. W. Grainger, Langmuir 12, 5083 (1996).

    CAS  Article  Google Scholar 

  25. 25

    See supplementary material at url for the basis for calculating the value of inelastic mean free path of Au 4f photoelectrons through poly (ethylene glycol) using equation S1 and S2 is described in page 2. High resolution C 1s and S 2p x-ray photoelectron spectra of various mixed monolayer and control surfaces are presented in Figure S1. The contact angles for water, formamide and α-bromonapthalene measured on various mixed monolayer surfaces are shown in Table S1a. The Lifshitz van der Waals component (ie187-1), electron acceptor component (ie187-2), electron donor component (ie187-3 ) of water, formamide and α-Bromonapthalene, the solvents used to calculate surface energy components, are presented in Table S1b. Representative QCM plots showing the change in frequency upon exposure to 10 % FBS on various mixed monolayer and control surfaces are presented in Figure S2.

  26. 26

    P. J. Cumpson, Surf. Interface Anal. 31, 23 (2001).

    CAS  Article  Google Scholar 

  27. 27

    C. J. Van Oss, M. K. Chaudhury, and R. J. Good, Chem. Rev. 88, 927 (1988).

    Article  Google Scholar 

  28. 28

    K. Sweers, K. van der Werf, M. Bennink, and V. Subramaniam, Nanoscale Res. Lett. 6, 270 (2011).

    CAS  Article  Google Scholar 

  29. 29

    E. B. Troughton, C. D. Bain, G. M. Whitesides, R. G. Nuzzo, D. L. Allara, and M. D. Porter, Langmuir 4, 365 (1988).

    CAS  Article  Google Scholar 

  30. 31

    M. A. Cole, H. Thissen, D. Losic, and N. H. Voelcker, Surf. Sci. 601, 1716 (2007).

    CAS  Article  Google Scholar 

  31. 32

    B. Menz, R. Knerr, A. Göpferich, and C. Steinem, Biomaterials 26, 4237 (2005).

    CAS  Article  Google Scholar 

  32. 33

    M. R. Nejadnik, H. C. van der Mei, W. Norde, and H. J. Busscher, Biomaterials 29, 4117 (2008).

    CAS  Article  Google Scholar 

  33. 34

    S. Tokumitsu, A. Liebich, S. Herrwerth, W. Eck, M. Himmelhaus, and M. Grunze, Langmuir 18, 8862 (2002).

    CAS  Article  Google Scholar 

  34. 35

    E. Ostuni, R. G. Chapman, M. N. Liang, G. Meluleni, G. Pier, D. E. Ingber, and G. M. Whitesides, Langmuir 17, 6336 (2001).

    CAS  Article  Google Scholar 

Download references

Author information



Corresponding authors

Correspondence to Ryosuke Ogaki or Peter Kingshott.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lokanathan, A.R., Zhang, S., Regina, V.R. et al. Mixed poly (ethylene glycol) and oligo (ethylene glycol) layers on gold as nonfouling surfaces created by backfilling. Biointerphases 6, 180–188 (2011).

Download citation