Protein diffusion in agarose hydrogel in situ measured by improved refractive index method

Songmiao Liang, Jian Xu, Lihui Weng, Hongjun Dai, Xiaoli Zhang, Lina Zhang

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82 Scopus citations


The accurate knowledge of the diffusion behavior of protein within biomimetic hydrogel matrix at body temperature has a great implication for the design of efficient controlled release protein-base drug delivery devices. In this paper, we improved our previous in situ refractive index method with great temperature-controlled capability. For the first time, this newly improved method was employed to study the diffusion of protein (bovine serum albumin (BSA) and lysozyme) in agarose hydrogel at body temperature (37 °C). The change of the gel refractive index caused by the change of the diffusing protein concentration within the gel during the diffusion process enables the effective diffusion coefficients of protein to be estimated. The diffusion coefficients of proteins decrease with the increase of the concentration of agarose and the solute molecular size. At the considered range of agarose concentration (0.5-3.0 wt.%), the diffusion coefficients range from 4.98 to 8.21 × 10- 7 cm2/s for BSA and 1.15 to 1.56 × 10- 6 cm2/s for lysozyme, respectively. Temperature dependence of diffusivity of BSA in agarose hydrogel was also investigated. Furthermore, the retardance effect of polymer volume fraction on the diffusivity of both BSA and lysozyme in agarose hydrogels was analyzed with three models, Amsden's, Clauge and Philips', and Ogsten's model.

Original languageEnglish (US)
Pages (from-to)189-196
Number of pages8
JournalJournal of Controlled Release
Issue number2
StatePublished - Oct 10 2006

Bibliographical note

Funding Information:
This work was supported by The National Natural Science Foundation of China (Grant Nos. 50425312, 50521302 and 20574076) and CAS Innovation Project.


  • Agarose hydrogel
  • Bovine serum albumin
  • Diffusion
  • Lysozyme
  • Refractive index

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