Thermodynamic characterization of selected biomaterial surfaces: Comparison of surface free energy approaches
Source abstract
Abstract
The thermodynamic surface properties of biomaterials play a key role in governing interfacial interactions and are commonly characterized by surface free energy (SFE) and its components derived from wetting data. However, different theoretical approaches used for SFE determination may yield substantially different results, particularly for polar and high-energy surfaces. In this study, the total surface free energy and its components were systematically analyzed for a range of clinically relevant biomaterial surfaces, including titanium, gold, cobalt–chromium alloy, nano-hydroxyapatite, and amorphous Teflon, prepared as smooth thin films on glass substrates. Static contact angles with water, glycerol, ethylene glycol, and diiodomethane were measured to assess wettability and to calculate SFE using three commonly applied models: the Owens–Wendt–Rabel–Kaelble (geometric mean) approach, the Lifshitz–van der Waals/acid–base (LW–AB) approach, and the equation of state (EOS) approach. These models estimate total SFE as well as nonpolar, polar, and acid–base components, enabling a detailed comparison of model-dependent surface energetic data. The results show good agreement between the different approaches for low-energy, hydrophobic surfaces, whereas pronounced discrepancies occur for hydrophilic, high-energy materials, particularly in the calculated polar and acid–base contributions. While total SFE values were partly consistent across methods, the relative magnitudes of individual SFE components strongly depended on the applied theoretical model. Overall, this study highlights that SFE should not be considered an intrinsic material property but a model-dependent descriptor. Careful selection of the SFE calculation approach and cautious interpretation of SFE components are essential when using thermodynamic surface analysis to compare biomaterial surfaces or to relate surface energetics to interfacial phenomena such as biofilm formation.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Polymer Surface Interaction Studies · Surface Modification and Superhydrophobicity · Adhesion, Friction, and Surface Interactions
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Medical Materials Science and Technology (MWT), Institute of Biomedical Engineering, University Hospital Tuebingen, Germany
Institute for Applied Physics, University of Tuebingen, Germany
References (53)
Show source-provided references
1. 10.1098/rstl.1805.000510.1098/rstl.1805.0005 ↗
2. Rupp F Gittens RA Scheideler L et al. A review on the wettability of dental implant surfaces I: theoretical and experimental aspects. Acta Biomater 2014; 10: 2894–2906. https://doi.org/10.1016/j.actbio.2014.02.04010.1016/j.actbio.2014.02.040 ↗
3. Gittens RA Scheideler L Rupp F et al. A review on the wettability of dental implant surfaces II: biological and clinical aspects. Acta Biomater 2014; 10: 2907–2918. https://doi.org/10.1016/j.actbio.2014.03.03210.1016/j.actbio.2014.03.032 ↗
4. Shui G Zhao Q Chu H et al. Engineering the surface wettability: recent advances in oil-water separation membranes. Energy Environ Sustain 2025; 1: 100040. https://doi.org/10.1016/j.eesus.2025.10004010.1016/j.eesus.2025.100040 ↗
5. Wang Y Zhai W Cheng S et al. Surface-functionalized design of blood-contacting biomaterials for preventing coagulation and promoting hemostasis. Friction 2023; 11: 1371–1394. https://doi.org/10.1007/s40544-022-0710-x10.1007/s40544-022-0710-x ↗
6. Wang Y Sun Y Xue Y et al. Functional surfaces with reversibly switchable wettability: fundamentals progresses applications and challenges. Prog Org Coat 2024; 188: 188. https://doi.org/10.1016/j.porgcoat.2023.10816710.1016/j.porgcoat.2023.108167 ↗
7. Bryers JD. Medical biofilms. Biotechnol Bioeng 2008; 100: 1–18. https://doi.org/10.1002/bit.2183810.1002/bit.21838 ↗
8. Costerton JW Stewart PS Greenberg EP. Bacterial biofilms: a common cause of persistent infections. Science 1999; 284: 1318–1322. https://doi.org/10.1126/science.284.5418.131810.1126/science.284.5418.1318 ↗
9. Donlan RM Costerton JW. Biofilms: survival mechanisms of clinically relevant microorganisms. Clin Microbiol Rev 2002; 15: 167–193. https://doi.org/10.1128/CMR.15.2.167-193.200210.1128/CMR.15.2.167-193.2002 ↗
10. Schachter B. Slimy business–the biotechnology of biofilms. Nat Biotechnol 2003; 21: 361–365. https://doi.org/10.1038/nbt0403-36110.1038/nbt0403-361 ↗
11. Sahoo K Meshram S. Biofilm formation in chronic infections: a comprehensive review of pathogenesis clinical implications and novel therapeutic approaches. Cureus 2024; 16: e70629. https://doi.org/10.7759/cureus.7062910.7759/cureus.70629 ↗
12. Kronström M, Svenson B, Hellman M, et al. Early implant failures in patients treated with Brånemark system titanium dental implants: a retrospective study. Int J Oral Maxillofac Implants 2001; 16: 201–207.
13. Wang Y Zhang L Xie B et al. The 50 most cited articles on soft tissue integration of dental implants: a bibliometric analysis. J Prosthet Dent 2025; 133: 713–723. https://doi.org/10.1016/j.prosdent.2024.07.01310.1016/j.prosdent.2024.07.013 ↗
14. Rupp F Liang L Geis-Gerstorfer J et al. Surface characteristics of dental implants: a review. Dent Mater 2018; 34: 40–57. https://doi.org/10.1016/j.dental.2017.09.00710.1016/j.dental.2017.09.007 ↗
15. An YH Friedman RJ. Concise review of mechanisms of bacterial adhesion to biomaterial surfaces. J Biomed Mater Res 1998; 43: 338–348. https://doi.org/10.1002/(sici)1097-4636(199823)43:3<3.0.co;2-b10.1002/(SICI)1097-4636(199823)43:3<338::AID-JBM16>3.0.CO;2-B ↗
16. Sardin S Morrier JJ Benay G et al. In vitro streptococcal adherence on prosthetic and implant materials. Interactions with physicochemical surface properties. J Oral Rehabil 2004; 31: 140–148. https://doi.org/10.1046/j.0305-182x.2003.01136.x10.1046/j.0305-182X.2003.01136.x ↗
17. Bakker DP Postmus BR Busscher HJ et al. Bacterial strains isolated from different niches can exhibit different patterns of adhesion to substrata. Appl Environ Microbiol 2004; 70: 3758–3760. https://doi.org/10.1128/AEM.70.6.3758-3760.200410.1128/AEM.70.6.3758-3760.2004 ↗
18. Gómez-Suárez C Busscher HJ van der Mei HC. Analysis of bacterial detachment from substratum surfaces by the passage of air-liquid interfaces. Appl Environ Microbiol 2001; 67: 2531–2537. https://doi.org/10.1128/AEM.67.6.2531-2537.200110.1128/AEM.67.6.2531-2537.2001 ↗
19. Katsikogianni M Missirlis YF. Concise review of mechanisms of bacterial adhesion to biomaterials and of techniques used in estimating bacteria-material interactions. Eur Cell Mater 2004; 8: 37–57. https://doi.org/10.22203/ecm.v008a0510.22203/eCM.v008a05 ↗
20. Hermansson M. The DLVO theory in microbial adhesion. Colloid Surface B 1999; 14: 105–119. https://doi.org/10.1016/S0927-7765(99)00029-610.1016/S0927-7765(99)00029-6 ↗
21. van Oss CJ. Surface free energy contribution to cell interactions. In: Glaser R Gingell D (eds) Biophysics of the Cell Surface. Springer Series in Biophysics vol 5. Springer Berlin Heidelberg 1990. https://doi.org/10.1007/978-3-642-74471-6_810.1007/978-3-642-74471-6_8 ↗
22. Absolom DR Lamberti FV Policova Z et al. Surface thermodynamics of bacterial adhesion. Appl Environ Microbiol 1983; 46: 90–97. https://doi.org/10.1128/aem.46.1.90-97.198310.1128/aem.46.1.90-97.1983 ↗
23. Sharma PK Rao KH. Analysis of different approaches for evaluation of surface energy of microbial cells by contact angle goniometry. Adv Colloid Interface Sci 2002; 98: 341–463. https://doi.org/10.1016/s0001-8686(02)00004-010.1016/S0001-8686(02)00004-0 ↗
24. Van Oss CJ Chaudhury MK Good RJ. Interfacial Lifshitz-van der Waals and polar interactions in macroscopic systems. Chem Rev 1988; 88: 927–941. https://doi.org/10.1021/cr00088a00610.1021/cr00088a006 ↗
25. Kwok DY Lee Y Neumann AW. Evaluation of the Lifshitz−van Der Waals/acid−base approach to determine interfacial tensions. 2. Interfacial tensions of liquid−liquid systems. Langmuir 1998; 14: 2548–2553. https://doi.org/10.1021/la970460e10.1021/la970460e ↗
26. Kwok DY Li D Neumann AW. Evaluation of the Lifshitz-van der Waals/acid-base approach to determine interfacial tensions. Langmuir 1994; 10: 1323–1328. https://doi.org/10.1021/la00016a05710.1021/la00016a057 ↗
27. Wu W Giese RFJ van Oss CJ. Evaluation of the Lifshitz-van der Waals/acid-base approach to determine surface tension components. Langmuir 1995; 11: 379–382. https://doi.org/10.1021/la00001a06410.1021/la00001a064 ↗
28. Kaelble DH. Dispersion-polar surface tension properties of organic solids. J Adhes 1970; 2: 66–81. https://doi.org/10.1080/002184670854458210.1080/0021846708544582 ↗
29. Neumann AW Good RJ Hope CJ et al. An equation-of-state approach to determine surface tensions of low-energy solids from contact angles. J Colloid Interface Sci 1974; 49: 291–304. https://doi.org/10.1016/0021-9797(74)90365-810.1016/0021-9797(74)90365-8 ↗
30. Bollen CML Lambrechts P Quirynen M. Comparison of surface roughness of oral hard materials to the threshold surface roughness for bacterial plaque retention: a review of the literature. Dent Mater 1997; 13: 258–269. https://doi.org/10.1016/s0109-5641(97)80038-310.1016/S0109-5641(97)80038-3 ↗
31. Zhu X Eibl O Scheideler L et al. Characterization of nano hydroxyapatite/collagen surfaces and cellular behaviors. J Biomed Mater Res A 2006; 79: 114–127. https://doi.org/10.1002/jbm.a.3070610.1002/jbm.a.30706 ↗
32. Zhu X Eibl O Berthold C et al. Structural characterization of nanocrystalline hydroxyapatite and adhesion of pre-osteoblast cells. Nanotechnol 2006; 17: 2711–2721. https://doi.org/10.1088/0957-4484/17/11/00110.1088/0957-4484/17/11/001 ↗
33. Li D Neumann AW. A reformulation of the equation of state for interfacial tensions. J Colloid Interface Sci 1990; 137: 304–307. https://doi.org/10.1016/0021-9797(90)90067-X10.1016/0021-9797(90)90067-X ↗
34. Li D Neumann AW. Contact angles on hydrophobic solid surfaces and their interpretation. J Colloid Interface Sci 1992; 148: 190–200. https://doi.org/10.1016/0021-9797(92)90127-810.1016/0021-9797(92)90127-8 ↗
35. Owens DK Wendt RC. Estimation of the surface free energy of polymers. J Appl Polym Sci 1969; 13: 1741–1747. https://doi.org/10.1002/app.1969.07013081510.1002/app.1969.070130815 ↗
36. Rabel W. Einige Aspekte der Benetzungstheorie und ihre Anwendung auf die Untersuchung und Veränderung der Oberflächeneigenschaften von Polymeren. Farbe und Lack 1971; 10: 997–1005.
37. Erbil Y. Surface tension of polymers. In: Birdi KS (ed.) Handbook of surface and colloid chemistry. CRC Press, 1997, p.265-307.
38. Ström G Fredriksson M Stenius P. Contact angles work of adhesion and interfacial tensions at a dissolving hydrocarbon surface. J Colloid Interface Sci 1987; 119: 352–361. https://doi.org/10.1016/0021-9797(87)90280-310.1016/0021-9797(87)90280-3 ↗
39. Van Oss CJ Ju L Chaudhury MK et al. Estimation of the polar parameters of the surface tension of liquids by contact angle measurements on gels. J Colloid Interface Sci 1989; 128: 313–319. https://doi.org/10.1016/0021-9797(89)90345-710.1016/0021-9797(89)90345-7 ↗
40. Bonn D Eggers J Indekeu J et al. Wetting and spreading. Rev Mod Phys 2009; 81: 739–805. https://doi.org/10.1103/RevModPhys.81.73910.1103/RevModPhys.81.739 ↗
41. Hu H Larson RG. Evaporation of a sessile droplet on a substrate. J Phys Chem B 2002; 106: 1334–1344. https://doi.org/10.1021/jp011832210.1021/jp0118322 ↗
42. Bellon-Fontaine MN Mozes N van der Mei HC et al. A comparison of thermodynamic approaches to predict the adhesion of dairy microorganisms to solid substrata. Cell Biophys 1990; 17: 93–106. https://doi.org/10.1007/BF0298980510.1007/BF02989805 ↗
43. Janczuk B Bruque JM Gonzalez Martin ML et al. The usefulness of the equation of state for interfacial tensions estimation in some liquid-liquid and solid-liquid systems. J Colloid Interface Sci 1996; 181: 108–117. https://doi.org/10.1006/jcis.1996.036110.1006/jcis.1996.0361 ↗
44. Chibowski E Perea-Carpio R. Problems of contact angle and solid surface free energy determination. Adv Colloid Interfac 2002; 98: 245–264. https://doi.org/10.1016/S0001-8686(01)00097-510.1016/S0001-8686(01)00097-5 ↗
45. Rupp F Illing B Felde N et al. Fluorine plasma etching modulates submicron topography physico-chemical aging and biological responses of titanium dental implants. Dent Mater 2026; 42: 648–660. https://doi.org/10.1016/j.dental.2025.12.00610.1016/j.dental.2025.12.006 ↗
46. Bos R van der Mei HC Busscher HJ. Physico-chemistry of initial microbial adhesive interactions – its mechanisms and methods for study. FEMS Microbiol Rev 1999; 23: 179–229. https://doi.org/10.1016/s0168-6445(99)00004-210.1016/S0168-6445(99)00004-2 ↗
47. Hallab NJ Bundy KJ O’Connor K et al. Evaluation of metallic and polymeric biomaterial surface energy and surface roughness characteristics for directed cell adhesion. Tissue Eng 2001; 7: 55–71. https://doi.org/10.1089/10763270030000329710.1089/107632700300003297 ↗
48. Drake DR, Paul J, Keller JC. Primary bacterial colonization of implant surfaces. Int J Oral Maxillofac Implants 1999; 14: 226–232.
49. Götz F. Staphylococcus and biofilms. Mol Microbiol 2002; 43: 1367–1378. https://doi.org/10.1046/j.1365-2958.2002.02827.x10.1046/j.1365-2958.2002.02827.x ↗
50. Quirynen M Bollen CML. The influence of surface roughness and surface-free energy on supra- and subgingival plaque formation in man. J Clin Periodontol 1995; 22: 1–14. https://doi.org/10.1111/j.1600-051x.1995.tb01765.x10.1111/j.1600-051X.1995.tb01765.x ↗
51. Subramani K, Jung RE, Molenberg A, et al. Biofilm on dental implants: a review of the literature. Int J Oral Maxillofac Implants 2009; 24: 616–626.
52. Zhao A Sun J Liu Y. Understanding bacterial biofilms: from definition to treatment strategies. Front Cell Infect Microbiol 2023; 13: 1137947. https://doi.org/10.3389/fcimb.2023.113794710.3389/fcimb.2023.1137947 ↗
53. Absolom DR. The role of bacterial hydrophobicity in infection: bacterial adhesion and phagocytic ingestion. Can J Microbiol 1988; 34: 287–298. https://doi.org/10.1139/m88-05410.1139/m88-054 ↗