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Indentation: A simple, nondestructive method for characterizing the mechanical and transport properties of pH-sensitive hydrogels

Published online by Cambridge University Press:  23 November 2011

Yuhang Hu ,
Jin-Oh You ,
Debra T. Auguste ,
Zhigang Suo  and
Joost J. Vlassak
Yuhang Hu
Affiliation:
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
Jin-Oh You
Affiliation:
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
Debra T. Auguste
Affiliation:
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
Zhigang Suo
Affiliation:
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
Joost J. Vlassak*
Affiliation:
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
*
a)Address all correspondence to this author. e-mail: vlassak@esag.harvard.edu
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Abstract

We use instrumented indentation to characterize the mechanical and transport behavior of a pH-sensitive hydrogel in various aqueous buffer solutions. In the measurement, an indenter is pressed to a fixed depth into a hydrogel disk and the load on the indenter is recorded as a function of time. By analyzing the load–relaxation curve using the theory of poroelasticity, the elastic constants of the hydrogel and the diffusivity of water in the gel can be evaluated. We investigate how the pH and ionic strength of the buffer solution, the hydrogel cross-link density, and the density of functional groups on the polymer backbone affect the properties of the hydrogel. This work demonstrates the utility of indentation techniques in the characterization of pH-sensitive hydrogels.

Keywords

DiffusionElastic properties
Type
Articles
Information
Journal of Materials Research , Volume 27 , Issue 1: Focus Issue: Instrumented Indentation , 14 January 2012 , pp. 152 - 160
Copyright
Copyright © Materials Research Society 2011

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References

REFERENCES

1.Tanaka, T.: Collapse of gels and the critical endpoint. Phys. Rev. Lett. 40, 820 (1978).CrossRefGoogle Scholar
2.Tanaka, T., Nishio, I., Sun, S-T., and Ueno-Nishio, S.: Collapse of gels in an electric field. Science 218, 467 (1982).CrossRefGoogle ScholarPubMed
3.Suzuki, A. and Tanaka, T.: Phase transition in polymer gels induced by visible light. Nature 346, 345 (1990).CrossRefGoogle Scholar
4.Tanaka, T. and Fillmore, D., Sun, S-T., Nishio, I., Swislow, G., and Shah, A.: Phase transitions in ionic gels. Phys. Rev. Lett. 45, 1636 (1980).CrossRefGoogle Scholar
5.Dong, L., Agarwal, A.K., Beebe, D.J., and Jiang, H.: Adaptive liquid microlenses activated by stimuli-responsive hydrogels. Nature 442, 551 (2006).CrossRefGoogle ScholarPubMed
6.Beebe, D. J., Moore, J. S., Bauer, J. M., Yu, Q., Liu, R. H., Devadoss, C., and Jo, B-H.: Functional hydrogel structures for autonomous flow control inside microfluidic channels. Nature 404, 588 (2000).CrossRefGoogle ScholarPubMed
7.Richter, A., Paschew, G., Klatt, S., Lienig, J., Arndt, K-F., and Adler, H-J.P.: Review on hydrogel-based pH sensors and microsensors. Sensors 8, 561 (2008).CrossRefGoogle ScholarPubMed
8.Gerlach, G., Guenther, M., Sorber, J., Subchaneck, G., Arndt, K-F., and Richter, A.: Chemical and pH sensors based on the swelling behavior of hydrogels. Sens. Actuat. B 111-112, 555 (2005).CrossRefGoogle Scholar
9.Jen, A.C., Wake, M.C., and Mikos, A.G.: Review: Hydrogels for cell immobilization. Biotechnol. Bioeng. 50, 357 (1996).3.0.CO;2-K>CrossRefGoogle ScholarPubMed
10.Jeong, B., Bae, Y.H., Lee, D.S., and Kim, S.W.: Biodegradable block copolymers as injectable drug delivery systems. Nature 388, 860 (1997).CrossRefGoogle ScholarPubMed
11.Qiu, Y. and Park, K.: Environment-sensitive hydrogels for drug delivery. Adv. Drug Delivery Rev. 53, 321 (2001).CrossRefGoogle ScholarPubMed
12.Hoare, T.R. and Kohane, D.S.: Hydrogels in drug delivery: Progress and challenges. Polymer 49, 1993 (2008).CrossRefGoogle Scholar
13.You, J. and Auguste, D.T.: Nanocarrier cross-linking density and pH sensitivity regulate intracellular gene transfer. Nano Lett. 9, 4467 (2009).CrossRefGoogle ScholarPubMed
14.Johnson, B.D., Beebe, D.J., and Crone, W.C.: Effects of swelling on the mechanical properties of pH-sensitive hydrogel for use in microfluidic devices. Mater. Sci. Eng., C 24, 575 (2004).CrossRefGoogle Scholar
15.Marra, S.P., Ramesh, K.T., and Douglas, A.S.: Mechanical characterization of active poly(vinyl alcohol)-poly(acrylic acid) gel. Mater. Sci. Eng., C 14, 25 (2001).CrossRefGoogle Scholar
16.Urayama, K., Takigawa, T., and Masuda, T.: Poisson’s ratio of poly(vinyl alcohol) gels. Macromolecules 26, 3092 (1993).CrossRefGoogle Scholar
17.Muniz, E.C. and Geuskens, G.: Compressive elastic modulus of polyacrylamide hydrogels and semi-IPNs with poly(N-isopropolacrylamide). Macromolecules 34, 4480 (2001).CrossRefGoogle Scholar
18.Zhao, X., Huebsch, N., Mooney, D.J., and Suo, Z.: Stress-relaxation behavior in gels with ionic and covalent crosslinks. J. Appl. Phys. 107, 063509 (2010).CrossRefGoogle ScholarPubMed
19.Cai, S., Hu, Y., Zhao, X., and Suo, Z.: Poroelasticity of a covalently crosslinked alginate hydrogel under compression. J. Appl. Phys. 108, 113514 (2010).CrossRefGoogle Scholar
20.Zhang, X., Hu, Z., and Li, Y.: Bending of bi-gels. J. Chem. Phys. 105, 3794 (1996).CrossRefGoogle Scholar
21.Scherer, G.W.: Measuring permeability of rigid materials by a beam-bending method: I. Theory. J. Am. Ceram. Soc. 83, 2231 (2000).CrossRefGoogle Scholar
22.Vichit-Vadakan, W. and Scherer, G.W.: Measuring permeability of rigid materials by a beam-bending method: II. Porous glass. J. Am. Ceram. Soc. 83, 2240 (2000).CrossRefGoogle Scholar
23.Stammen, J.A., Williams, S., Ku, D.N., and Guldberg, R.E.: Mechanical properties of a novel PVA hydrogel in shear and unconfined compression. Biomaterials 22, 799 (2001).CrossRefGoogle ScholarPubMed
24.Zimberlin, J.A., Sanabria-Delong, N., Tew, G.N., and Crosby, A.J.: Cavitation rheology for soft materials. Soft Matter 3, 763 (2007).CrossRefGoogle ScholarPubMed
25.Mason, T.G. and Weitz, D.A.: Optical measurements of frequency-dependent linear viscoelastic moduli of complex fluids. Phys. Rev. Lett. 74, 1250 (1995).CrossRefGoogle ScholarPubMed
26.MacKintosh, F.C. and Schmidt, C.F.: Microrheology. Curr. Opin. Colloid Interface Sci. 4, 300 (1999).CrossRefGoogle Scholar
27.Mukhopadhyay, A. and Granick, S.: Micro- and nanorheology. Curr. Opin. Colloid Interface Sci. 6, 423 (2001).CrossRefGoogle Scholar
28.Ebenstein, D.M. and Pruitt, L.A.: Nanoindentation of biological materials. Nano Today 1, 26 (2006).CrossRefGoogle Scholar
29.Constantinides, G., Kalcioglu, Z.I., McFarland, M., Smith, J.F., and Van Vliet, K.J.: Probing mechanical properties of fully hydrated gels and biological tissues. J. Biomech. 41, 3285 (2008).CrossRefGoogle ScholarPubMed
30.Kaufman, J.D., Miller, G.J., Morgan, E.F., and Klapperich, C.M.: Time-dependent mechanical characterization of poly(2-hydroxyethyl methacrylate) hydrogels using nanoindentation and unconfined compression. J. Mater. Res. 23, 1472 (2008).CrossRefGoogle ScholarPubMed
31.Galli, M., Comley, K.S.C., Shean, T.A.V., and Oyen, M.L.: Viscoelastic and poroelastic mechanical characterization of hydrated gels. J. Mater. Res. 24, 973 (2009).CrossRefGoogle Scholar
32.Hui, C.Y., Lin, Y.Y., Chuang, F.C., Shull, K.R., and Ling, W.C.: A contact mechanics method for characterizing the elastic properties and permeability of gels. J. Polym. Sci., part B: Polym. Phys. 43, 359 (2006).CrossRefGoogle Scholar
33.Lin, Y.Y. and Hu, B.W.: Load relaxation of a flat rigid circular indenter on a gel half space. J. Non-Cryst. Solids 352, 4034 (2006).CrossRefGoogle Scholar
34.Lin, W.C., Shull, K.R., Hui, C.Y., and Lin, Y.Y.: Contact measurement of internal fluid flow within poly(n-isopropylacrylamide) gels. J. Chem. Phys. 127, 094906 (2007).CrossRefGoogle ScholarPubMed
35.Galli, M. and Oyen, M.L.: Fast identification of poroelastic parameters from indentation tests. Comput. Model. Eng. Sci. 48, 241 (2009).Google Scholar
36.Hu, Y., Zhao, X., Vlassak, J.J., and Suo, Z.: Using indentation to characterize the poroelasticity of gels. Appl. Phys. Lett. 96, 121904 (2010).CrossRefGoogle Scholar
37.Hu, Y., Chen, X., Whitesides, G.M., Vlassak, J.J., and Suo, Z.: Indentation of polydimethylsiloxane submerged in organic solvents. J. Mater. Res. 26(6), 785 (2011).CrossRefGoogle Scholar
38.Hu, Y., Chan, E.P., Vlassak, J.J., and Suo, Z.: Poroelastic relaxation indentation of thin layers of gels. J. Appl. Phys. 110, 086103 (2011).CrossRefGoogle Scholar
39.Li, Y. and Tanaka, T.: Kinetics of swelling and shrinking of gels. J. Chem. Phys. 92, 1365 (1990).CrossRefGoogle Scholar
40.Doi, M.: Gel dynamics. J. Phys. Soc. Jpn. 78, 052001 (2009).CrossRefGoogle Scholar
41.De, S.K., Aluru, N.R., Johnson, B., Crone, W.C., Beebe, D.J., and Moore, J.: Equilibrium swelling and kinetics of pH-responsive hydrogels: Models, experiments, and simulations. J. Microelectromech. Syst. 11, 544 (2002).CrossRefGoogle Scholar
42.Traitel, T., Cohen, Y., and Kost, J.: Characterization of glucose-sensitive insulin release systems in simulated in vivo conditions. Biomaterials 21, 1679 (2000).CrossRefGoogle ScholarPubMed
43.Brannon-Peppas, L. and Peppas, K.A.: Time-dependent response of ionic polymer networks to pH and ionic strength changes. Int. J. Pharm. 70, 53 (1991).CrossRefGoogle Scholar
44.Bell, C.L. and Peppas, N.A.: Water, solute and protein diffusion in physiologically responsive hydrogels of poly(methacrylic acid-g-ethylene glycol). Biomaterials 17, 1203 (1996).CrossRefGoogle ScholarPubMed
45.Pishko, G.L., Lee, S.J., Wanakule, P., and Sarntinoranont, M.: Hydraulic permeability of a hydrogel-based contact lens membrane for low flow rates. J. Appl. Polym. Sci. 104, 3730 (2007).CrossRefGoogle Scholar
46.Lightfoot, E.J.: Kinetic diffusion in polymer gels. Physica A 169, 191 (1990).CrossRefGoogle Scholar
47.Terzaghi, K.: Die berechnung der durchlässigkeitsziffer des tones aus dem verlauf der hydrodynamischen spannungsercheinungen. Sitzungsber. Akad. Wiss. Wien Math. –Naturewiss. Kl., Abt. IIa. 132, 125 (1923).Google Scholar
48.Biot, M.A.: General theory of three-dimensional consolidation. J. Appl. Phys. 12, 155 (1941).CrossRefGoogle Scholar
49.Sneddon, I.N.: The relation between load and penetration in the axisymmetric Boussinesq problem for a punch of arbitrary profile. Int. J. Eng. Sci. 3, 47 (1965).CrossRefGoogle Scholar
50.Yıldız, B., Işık, B., Kış, M., and Birgül, Ö: pH-sensitive dimethylaminoethyl methacrylate (DMAEMA)/acrylamide (AAm) hydrogels: Synthesis and adsorption from uranyl acetate solutions. J. Appl. Polym. Sci. 88, 2028 (2003).CrossRefGoogle Scholar
51.http://home.fuse.net/clymer/buffers/phos2.html.Google Scholar
52.Flory, P.J.: Principles of Polymer Chemistry (Cornell University, Ithaca, 1953).Google Scholar
53.Susoff, M. and Oppermann, W.: Influence of cross-linking on probe dynamics in semidilute polystyrene systems. Macromolecules 43, 9100 (2010).CrossRefGoogle Scholar