Double protein functionalized poly-ε-caprolactone surfaces: in depth ToF–SIMS and XPS characterization



In biomaterial research, great attention has focussed on the immobilization of biomolecules with the aim to increase cell-adhesive properties of materials. Many different strategies can be applied. In previously published work, our group focussed on the treatment of poly-ε-caprolactone (PCL) films by an Ar-plasma, followed by the grafting of 2-aminoethyl methacrylate (AEMA) under UV-irradiation. The functional groups introduced, enabled the subsequent covalent immobilisation of gelatin. The obtained coating was finally applied for the physisorption of fibronectin. The successful PCL surface functionalization was preliminary confirmed using XPS, wettability studies, AFM and SEM. In the present article, we report on an in-depth characterization of the materials developed using ToF–SIMS and XPS analysis. The homogeneous AEMA grafting and the subsequent protein coating steps could be confirmed by both XPS and ToF–SIMS. Using ToF–SIMS, it was possible to demonstrate the presence of polymethacrylates on the surface. From peak deconvoluted XPS results (C- and N-peak), the presence of proteins could be confirmed. Using ToF–SIMS, different positive ions, correlating to specific amino-acids could be identified. Importantly, the gelatin and the fibronectin coatings could be qualitatively distinguished. Interestingly for biomedical applications, ethylene oxide sterilization did not affect the surface chemical composition. This research clearly demonstrates the complementarities of XPS and ToF–SIMS in biomedical surface modification research.


Gelatin Polymethacrylates Ethylene Oxide Sterilization Surface Modification Strategy Double Protein 



The authors would like to thank Ghent University (UGent, BOF project), the UGent Multidisciplinary Research Partnership Nano- and biophotonics (2010-2015) and the Catholic University of Louvain-la-Neuve for financial support. A special thanks to Claude Poleunis for performing ToF–SIMS, to Michel Genet for his support in the XPS interpretation and to Thomas Billiet for the interesting discussions.


  1. 1.
    Desmet T, Schacht E, Dubruel P. Rapid prototyping as an elegant production tool for polymeric tissue engineering scaffolds: a review. In: Barnes SJ, Harris LP, editors. Tissue engineering: roles, materials and applications. New York: Nova Science Publishers, Inc.; 2008; p. 141–189.Google Scholar
  2. 2.
    Desmet T, Morent R, De Geyter N, Leys C, Schacht E, Dubruel P. Nonthermal plasma technology as a versatile strategy for polymeric biomaterials surface modification: a review. Biomacromolecules. 2009;10(9):2351–78.CrossRefGoogle Scholar
  3. 3.
    Goddard JM, Hotchkiss JH. Polymer surface modification for the attachment of bioactive compounds. Prog Polym Sci. 2007;32(7):698–725.CrossRefGoogle Scholar
  4. 4.
    Jagielski J, Turos A, Biefinski D, Abdul-Kader AM, Platkowska A. Ion-beam modified polymers for biomedical applications. Nucl Instrum Method Phys Res Sect B-Beam Interact Mater Atoms. 2007;261(1–2):690–3.CrossRefGoogle Scholar
  5. 5.
    Marletta G, Ciapetti G, Satriano C, Pagani S, Baldini N. The effect of irradiation modification and RGD sequence adsorption on the response of human osteoblasts to polycaprolactone. Biomaterials. 2005;26(23):4793–804.CrossRefGoogle Scholar
  6. 6.
    Sioshansi P, Tobin EJ. Surface treatment of biomaterials by ion beam processes. Surf Coat Technol. 1996;83(1–3):175–82.CrossRefGoogle Scholar
  7. 7.
    Zhu AP, Zhao F, Ma T. Photo-initiated grafting of gelatin/N-maleic acyl-chitosan to enhance endothelial cell adhesion, proliferation and function on PLA surface. Acta Biomater. 2009;5(6):2033–44.CrossRefGoogle Scholar
  8. 8.
    Truica-Marasescu F, Wertheimer MR. Vacuum-ultraviolet photopolymerisation of amine-rich thin films. Macromol Chem Phys. 2008;209(10):1043–9.CrossRefGoogle Scholar
  9. 9.
    Farquet P, Padeste C, Solak HH, Gursel SA, Scherer GG, Wokaun A. EUV lithographic radiation grafting of thermo-responsive hydrogel nanostructures. Nucl Instrum Method Phys Res Sect B-Beam Interact Mater Atoms. 2007;265(1):187–92.CrossRefGoogle Scholar
  10. 10.
    Wirsen A, Sun H, Albertsson AC. Solvent-free vapor-phase photografting of acrylamide onto poly(ethylene terephthalate). Biomacromolecules. 2005;6(5):2697–702.CrossRefGoogle Scholar
  11. 11.
    Bullett NA, Bullett DP, Truica-Marasescu FE, Lerouge S, Mwale F, Wertheimer MR. Polymer surface micropatterning by plasma and VUV-photochemical modification for controlled cell culture. Appl Surf Sci. 2004;235(4):395–405.CrossRefGoogle Scholar
  12. 12.
    Mathieson I, Bradley RH. Improved adhesion to polymers by UV/ozone surface oxidation. Int J Adhes Adhes. 1996;16(1):29–31.CrossRefGoogle Scholar
  13. 13.
    Siow KS, Britcher L, Kumar S, Griesser HJ. Plasma methods for the generation of chemically reactive surfaces for biomolecule immobilization and cell colonization: a review. Plasma Process Polym. 2006;3(6–7):392–418.CrossRefGoogle Scholar
  14. 14.
    Desmet T, Billiet T, Berneel E, Cornelissen R, Schaubroeck D, Schacht E, Dubruel P. Post-plasma grafting of AEMA as a versatile tool to biofunctionalise polyesters for tissue engineering. Macromol Biosci. 2010;10:1484–94.CrossRefGoogle Scholar
  15. 15.
    Chim H, Hutmacher DW, Chou AM, Oliveira AL, Reis RL, Lim TC, Schantz JT. A comparative analysis of scaffold material modifications for load-bearing applications in bone tissue engineering. Int J Oral Maxillofac Surg. 2006;35(10):928–34.CrossRefGoogle Scholar
  16. 16.
    Hsu SH, Yen HJ, Tseng CS, Cheng CS, Tsai CL. Evaluation of the growth of chondrocytes and osteoblasts seeded into precision scaffolds fabricated by fused deposition manufacturing. J Biomed Mater Res Part B-Appl Biomater. 2007;80B(2):519–27.CrossRefGoogle Scholar
  17. 17.
    Olah L, Filipczak K, Jaegermann Z, Czigany T, Borbas L, Sosnowski S, Ulanski P, Rosiak JM. Synthesis, structural and mechanical properties of porous polymeric scaffolds for bone tissue regeneration based on neat poly(epsilon-caprolactone) calcium carbonate. Polym Adv Technol. 2006;17(11–12):889–97.CrossRefGoogle Scholar
  18. 18.
    Perale G, Pertici G, Giordano C, Daniele F, Masi M, Maccagnan S. Nondegradative microextrusion of resorbable polyesters for pharmaceutical and biomedical applications: the cases of poly-lactic-acid and poly-caprolactone. J Appl Polym Sci. 2008;108(3):1591–5.CrossRefGoogle Scholar
  19. 19.
    Savarino L, Baldini N, Greco M, Capitani O, Pinna S, Valentini S, Lombardo B, Esposito MT, Pastore L, Ambrosio L, Battista S, Causa F, Zeppetelli S, Guarino V, Netti PA. The performance of poly-epsilon-caprolactone scaffolds in a rabbit femur model with and without autologous stromal cells and BMP4. Biomaterials. 2007;28(20):3101–9.CrossRefGoogle Scholar
  20. 20.
    Shor L, Guceri S, Wen XJ, Gandhi M, Sun W. Fabrication of three-dimensional polycaprolactone/hydroxyapatite tissue scaffolds and osteoblast-scaffold interactions in vitro. Biomaterials. 2007;28(35):5291–7.CrossRefGoogle Scholar
  21. 21.
    Wang F, Shor L, Darling A, Khalil S, Sun W, Guceri S, Lau A. Precision extruding deposition and characterization of cellular poly-epsilon-caprolactone tissue scaffolds. Rapid Prototyping Journal. 2004;10(1):42–9.CrossRefGoogle Scholar
  22. 22.
    Zein I, Hutmacher DW, Tan KC, Teoh SH. Fused deposition modeling of novel scaffold architectures for tissue engineering applications. Biomaterials. 2002;23(4):1169–85.CrossRefGoogle Scholar
  23. 23.
    Hutmacher DW, Schantz T, Zein I, Ng KW, Teoh SH, Tan KC. Mechanical properties and cell cultural response of polycaprolactone scaffolds designed and fabricated via fused deposition modeling. J Biomed Mater Res. 2001;55(2):203–16.CrossRefGoogle Scholar
  24. 24.
    Cheng ZY, Teoh SH. Surface modification of ultra thin poly (epsilon-caprolactone) films using acrylic acid and collagen. Biomaterials. 2004;25(11):1991–2001.CrossRefGoogle Scholar
  25. 25.
    Amato I, Ciapettia G, Pagani S, Marletta G, Satriano C, Baldini N, Granchi D. Expression of cell adhesion receptors in human osteoblasts cultured on biofunctionalized poly-(epsilon-caprolactone) surfaces. Biomaterials. 2007;28(25):3668–78.CrossRefGoogle Scholar
  26. 26.
    Gabriel M, Amerongen GPV, Van Hinsbergh VWM, Amerongen AVV, Zentner A. Direct grafting of RGD-motif-containing peptide on the surface of polycaprolactone films. J Biomat Sci-Polym Ed. 2006;17(5):567–77.CrossRefGoogle Scholar
  27. 27.
    Ma ZW, He W, Yong T, Ramakrishna S. Grafting of gelatin on electrospun poly(caprolactone) nanofibers to improve endothelial cell spreading and proliferation and to control cell orientation. Tissue Eng. 2005;11(7–8):1149–58.CrossRefGoogle Scholar
  28. 28.
    Marletta G, Ciapetti G, Satriano C, Perut F, Salerno M, Baldini N. Improved osteogenic differentiation of human marrow stromal cells cultured on ion-induced chemically structured poly-epsilon-caprolactone. Biomaterials. 2007;28(6):1132–40.CrossRefGoogle Scholar
  29. 29.
    Tiaw KS, Goh SW, Hong M, Wang Z, Lan B, Teoh SH. Laser surface modification of poly(epsilon-caprolactone) (PCL) membrane for tissue engineering applications. Biomaterials. 2005;26(7):763–9.CrossRefGoogle Scholar
  30. 30.
    Wirsen A, Sun H, Emilsson L, Albertsson AC. Solvent free vapor phase photografting of maleic anhydride onto poly(ethylene terephthalate) and surface coupling of fluorinated probes, PEG, and an RGD-peptide. Biomacromolecules. 2005;6(4):2281–9.CrossRefGoogle Scholar
  31. 31.
    Zhu YB, Gao CY, Liu XY, Shen JC. Surface modification of polycaprolactone membrane via aminolysis and biomacromolecule immobilization for promoting cytocompatibility of human endothelial cells. Biomacromolecules. 2002;3(6):1312–9.CrossRefGoogle Scholar
  32. 32.
    Yu TT, Shoichet MS. Guided cell adhesion and outgrowth in peptide-modified channels for neural tissue engineering. Biomaterials. 2005;26(13):1507–14.CrossRefGoogle Scholar
  33. 33.
    Yang Q, Xu ZK, Hu MX, Li JJ, Wu J. Novel sequence for generating glycopolymer tethered on a membrane surface. Langmuir. 2005;21(23):10717–23.CrossRefGoogle Scholar
  34. 34.
    Yang Q, Xu ZK, Ulbricht M. Surface modification of polypropylene microporous membrane by the immobilization of dextran. Chem J Chin Univ-Chin. 2005;26(1):189–91.Google Scholar
  35. 35.
    Yu HY, He JM, Liu LQ, He XC, Gu JS, Wei XW. Photoinduced graft polymerization to improve antifouling characteristics of an SMBR. J Membr Sci. 2007;302(1–2):235–42.CrossRefGoogle Scholar
  36. 36.
    Thompson KL, Read ES, Armes SP. Chemical degradation of poly(2-aminoethyl methacrylate). Polym Degrad Stab. 2008;93(8):1460–6.CrossRefGoogle Scholar
  37. 37.
    Van Vlierberghe S, Cnudde V, Dubruel P, Masschaele B, Cosijns A, De Paepe I, Jacobs PJS, Van Hoorebeke L, Remon JP, Schacht E. Porous gelatin hydrogels: 1 Cryogenic formation and structure analysis. Biomacromolecules. 2007;8(2):331–7.CrossRefGoogle Scholar
  38. 38.
    Ulubayram K, Eroglu I, Hasirci N. Gelatin microspheres and sponges for delivery of macromolecules. J Biomater Appl. 2002;16(3):227–41.CrossRefGoogle Scholar
  39. 39.
    Ren JR, Wang J, Sun H, Huang N. Surface modification of polyethylene terephthalate with albumin and gelatin for improvement of anticoagulation and endothelialization. Appl Surf Sci. 2008;255(2):263–6.CrossRefGoogle Scholar
  40. 40.
    Shin YM, Kim KS, Lim YM, Nho YC, Shin H. Modulation of spreading, proliferation, and differentiation of human mesenchymal stem cells on gelatin-immobilized poly(l-lactide-co-epsilon-caprolactone) substrates. Biomacromolecules. 2008;9(7):1772–81.CrossRefGoogle Scholar
  41. 41.
    Zhu YB, Gao CY, He T, Shen JC. Endothelium regeneration on luminal surface of polyurethane vascular scaffold modified with diamine and covalently grafted with gelatin. Biomaterials. 2004;25(3):423–30.CrossRefGoogle Scholar
  42. 42.
    Zhu YB, Gao CY, Liu XY, He T, Shen JC. Immobilization of biomacromolecules onto aminolyzed poly(l-lactic acid) toward acceleration of endothelium regeneration. Tissue Eng. 2004;10(1–2):53–61.CrossRefGoogle Scholar
  43. 43.
    Zhu YB, Gao CY, Shen JC. Surface modification of polycaprolactone with poly(methacrylic acid) and gelatin covalent immobilization for promoting its cytocompatibility. Biomaterials. 2002;23(24):4889–95.CrossRefGoogle Scholar
  44. 44.
    Vlierberghe SV, Vanderleyden E, Dubruel P, Vos FD, Schacht E. Affinity study of novel gelatin cell carriers for fibronectin. Macromol Biosci. 2009;9(11):1105–15.CrossRefGoogle Scholar
  45. 45.
    Chi YS, Lee JK, Lee KB, Kim DJ, Choi IS. Biosurface organic chemistry: Interfacial chemical reactions for applications to nanobiotechnology and biomedical sciences. Bull Korean Chem Soc. 2005;26(3):361–70.CrossRefGoogle Scholar
  46. 46.
    Vogel, V. Fibronectin in a surface-adsorbed state. In: Horbett TA, Brash JL, editors. Proteins at interfaces II, fundamentals and applications. Washington: American Chemical Society; 1995.Google Scholar
  47. 47.
    Altankov G, Thom V, Groth T, Jankova K, Jonsson G, Ulbricht M. Modulating the biocompatibility of polymer surfaces with poly(ethylene glycol): effect of fibronectin. J Biomed Mater Res. 2000;52(1):219–30.CrossRefGoogle Scholar
  48. 48.
    Badylak S, Liang A, Record R, Tullius R, Hodde J. Endothelial cell adherence to small intestinal submucosa: an acellular bioscaffold. Biomaterial. 1999;20(23–24):2257–63.CrossRefGoogle Scholar
  49. 49.
    Detrait E, Lhoest JB, Bertrand P, de Aguilar PV. Fibronectin-pluronic coadsorption on a polystyrene surface with increasing hydrophobicity: relationship to cell adhesion. J Biomed Mater Res. 1999;45(4):404–13.CrossRefGoogle Scholar
  50. 50.
    Suzuki M, Kishida A, Iwata H, Ikada Y. Graft-copolymerization of acrylamide onto a polyethylene surface pretreated with a glow-discharge. Macromolecules. 1986;19(7):1804–8.CrossRefGoogle Scholar
  51. 51.
    Chong MSK, Lee CN, Teoh SH. Characterization of smooth muscle cells on poly(epsilon-caprolactone) films. Mater Sci Eng C-Biomimetic Supramol Syst. 2007;27(2):309–12.CrossRefGoogle Scholar
  52. 52.
    Genet M, Dupont-Gillain C, Rouxhet P. XPS analysis of biosystems and biomaterials. In: Matijevi′c E, editor. Medical applications of colloids. New York: Springer; 2008, p. 177–307.Google Scholar
  53. 53.
    Briggs D, Surface analysis of polymers by XPS and static SIMS. Cambridge: Cambridge University Press; 1998, p xiii+198.Google Scholar
  54. 54.
    Canavan HE, Graham DJ, Cheng XH, Ratner BD, Castner DG. Comparison of native extracellular matrix with adsorbed protein films using secondary ion mass spectrometry. Langmuir. 2007;23(1):50–6.CrossRefGoogle Scholar
  55. 55.
    Vickerman JC, Briggs D, Henderson A. The Wiley static SIMS library. Chichester: Wiley; 1996, p. v.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • T. Desmet
    • 1
  • C. Poleunis
    • 2
  • A. Delcorte
    • 2
  • P. Dubruel
    • 1
  1. 1.Polymer Chemistry & Biomaterials Research GroupGhent UniversityGhentBelgium
  2. 2.Institute of Condensed Matter and Nanosciences (IMCN)-Bio and Soft Matter (BSMA)Université Catholique de Louvain (UCL)Louvain-la-NeuveBelgium

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