Electrochemically assisted bacteria encapsulation in thin hybrid sol-gel films

Area of Science:

• Biotechnology
• Materials Science
• Electrochemistry

Background:

• Bacterial immobilization is crucial for biosensors and biocatalysis.
• Traditional methods can compromise bacterial viability and function.
• Developing robust methods for long-term bacterial preservation is essential.

Purpose of the Study:

• To develop a novel electrochemical method for immobilizing bacteria in hybrid sol-gel films.
• To assess the viability and metabolic activity of immobilized Escherichia coli (E. coli) over time.
• To investigate the effect of additives on bacterial preservation within the sol-gel matrix.

Main Methods:

• Electrochemical manipulation of the sol-gel process for bacterial encapsulation.
• Incorporation of E. coli strains (C600, MG1655 pUCD607, MG1655 pZNTA-GFP) into hybrid sol-gel films.
• Assessment of bacterial membrane integrity and metabolic activity using LIVE/DEAD BacLight assay and epi-fluorescence microscopy.
• Evaluation of bacterial viability under different storage conditions (+4 °C and -80 °C) and with additives (chitosan, trehalose, polyethylene glycol).

Main Results:

• The electrochemical sol-gel method successfully immobilized E. coli on electrode surfaces.
• High preservation of membrane integrity (95%) was observed for E. coli C600 in the sol-gel film.
• Additives including chitosan, trehalose, and polyethylene glycol significantly enhanced E. coli viability for up to one month.
• Approximately 50% of E. coli MG1655 pUCD607 cells retained bioluminescent activity in the composite films.

Conclusions:

• Electrochemical sol-gel immobilization offers a safe and effective method for preserving bacterial viability.
• The addition of specific compounds can substantially improve the long-term survival of encapsulated bacteria.
• This technique holds promise for applications in biosensing and biocatalysis requiring stable bacterial populations.