2.5. Encapsulating of Thyme essential oils in CS-BA nanogel
The Thyme essential oils was dissolved in ethanol (1:1, v/v) and
mixtures of nanogels (500 mg/l) and essential oils (5000 mg/l),
were prepared by sonication (70 kHz) for 5 min. The encapsulation
efficiency was measured by a Shimadzu spectrophotometer (Japan,
http://www.shimadzu.com), based on the optical density spectra of
the essential oils (400e650 nm). The spectroscopic readings were
performed after precipitating the nanogel by centrifugation
(10,000 g, 15 min).
2.6. Determination of minimum inhibitory concentrations (MIC) of
CS-BA nanogel, free and CS-BA nanogel encapsulated Thyme
essential oils
Sterile Erlenmeyer flasks containing 25 ml of PDB medium,
150 spores and different concentrations of CS-BA nanogel, as well as
free and CS-BA nanogel-encapsulated Thyme essential oils were stored in an incubator for 1 month in order to determine the MIC.
Moreover, the MIC of T. vulgaris essential oils and CS-BA nanogelencapsulated
T. vulgaris essential oils were studied under two
different conditions; the flasks were sealed during the experiment
and otherwise.