MilliporeSigma
  • Yeast-based self-organized hybrid bio-silica sol-gels for the design of biosensors.

Yeast-based self-organized hybrid bio-silica sol-gels for the design of biosensors.

Biosensors & bioelectronics (2014-09-10)
O N Ponamoreva, O A Kamanina, V A Alferov, A V Machulin, T V Rogova, V A Arlyapov, S V Alferov, N E Suzina, E P Ivanova
ABSTRACT

The methylotrophic Pichia angusta VKM Y-2559 and the oleaginous Cryptococcus curvatus VKM Y-3288 yeast cells were immobilized in a bimodal silica-organic sol-gel matrix comprised of tetraethoxysilane (TEOS), the hydrophobic additive methyltriethoxysilane (MTES) and the porogen polyethylene glycol (PEG). Under carefully optimized experimental conditions, employing basic catalysts, yeast cells have become the nucleation centers for a silica-organic capsule assembled around the cells. The dynamic process involved in the formation of the sol-gel matrix has been investigated using optical and scanning electron microscopic techniques. The results demonstrated the influence of the MTES composition on the nature of the encapsulation of the yeast cells, together with the architecture of the three-dimensional (3D) sol-gel biomatrix that forms during the encapsulation process. A silica capsule was found to form around each yeast cell when using 85 vol% MTES. This capsule was found to protect the microorganisms from the harmful effects that result from exposure to heavy metal ions and UV radiation. The encapsulated P. angusta BKM Y-2559 cells were then employed as a biosensing element for the detection of methanol. The P. angusta-based biosensor is characterized by high reproducibility (Sr, 1%) and operational stability, where the biosensor remains viable for up to 28 days.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Osmium tetroxide, ReagentPlus®, 99.8%
Sigma-Aldrich
Glutaric dialdehyde solution, 50 wt. % in H2O, FCC
Sigma-Aldrich
Tetraethyl orthosilicate, reagent grade, 98%
Sigma-Aldrich
Tetraethyl orthosilicate, 99.999% trace metals basis
Sigma-Aldrich
Tetraethyl orthosilicate, ≥99.0% (GC)
Sigma-Aldrich
Glutaraldehyde solution, 50 wt. % in H2O
Sigma-Aldrich
Glutaraldehyde solution, Grade I, 50% in H2O, specially purified for use as an electron microscopy fixative or other sophisticated use
Sigma-Aldrich
Glutaraldehyde solution, Grade II, 25% in H2O
Sigma-Aldrich
Glutaraldehyde solution, Grade I, 70% in H2O, specially purified for use as an electron microscopy fixative or other sophisticated use
Sigma-Aldrich
Glutaraldehyde solution, Grade I, 25% in H2O, specially purified for use as an electron microscopy fixative
Sigma-Aldrich
Glutaraldehyde solution, 50% in H2O, suitable for photographic applications
Sigma-Aldrich
Osmium tetroxide, Sealed ampule.
Sigma-Aldrich
Glutaraldehyde solution, Grade I, 8% in H2O, specially purified for use as an electron microscopy fixative or other sophisticated use
Sigma-Aldrich
Tetraethyl orthosilicate, packaged for use in deposition systems
Sigma-Aldrich
Osmium tetroxide solution, suitable for electron microscopy, 2% in H2O
Sigma-Aldrich
Osmium tetroxide solution, suitable for electron microscopy, 4% in H2O
Sigma-Aldrich
Osmium tetroxide solution, 4 wt. % in H2O
Sigma-Aldrich
Osmium tetroxide solution, 2.5 wt. % in tert-butanol
Sigma-Aldrich
Osmium tetroxide, ACS reagent, ≥98.0%
Sigma-Aldrich
Os EnCat® 40, extent of labeling: 0.3 mmol/g Os loading