Structural study of (Hydroxypropyl)methyl cellulose microemulsion-based gels used for biocompatible encapsulations

Evdokia Vassiliadi, Evgenia Mitsou, Spyridon Avramiotis, Christos L. Chochos, Franz Pirolt, Martin Medebach, Otto Glatter, Aristotelis Xenakis, Maria Zoumpanioti*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


(Hydroxypropyl)methyl cellulose (HPMC) can be used to form gels integrating a w/o microemulsion. The formulation in which a microemulsion is mixed with a hydrated HPMC matrix has been successfully used as a carrier of biocompatible ingredients. However, little is known about the structure of these systems. To elucidate this, scanning electron microscopy was used to examine the morphology and the bulk of the microemulsion-based gels (MBGs) and small-angle X-ray scattering to clarify the structure and detect any residual reverse micelles after microemulsion incorporation in the gel. Electron paramagnetic resonance spectroscopy was applied using spin probes to investigate the polar and non-polar areas of the gel. Furthermore, the enzyme-labelling technique was followed to investigate the location of an enzyme in the matrix. A structural model for HPMC matrix is proposed according to which, although a w/o microemulsion is essential to form the final gel, no microemulsion droplets can be detected after incorporation in the gel. Channels are formed by the organic solvent (oil), which are coated by surfactant molecules and a water layer in which the enzyme can be hosted.

Original languageEnglish
Article number2204
Pages (from-to)1-20
Number of pages20
Issue number11
Publication statusPublished - Nov 2020


  • (hydroxypropyl)methyl cellulose (HPMC)
  • Electronparamagnetic resonance (EPR)
  • Lipase
  • Scanningelectronmicroscopy(SEM)
  • Small angle X-rayscattering(SAXS)

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)


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