Capillary electrophoresis of microbial aggregates

Area of Science:

• Analytical Chemistry
• Microbiology
• Biophysics

Background:

• Bacterial cell aggregation is a major challenge in electrophoretic separations.
• Understanding bacterial electrophoretic behavior is crucial for developing effective analytical methods.

Purpose of the Study:

• To investigate the electrophoretic behavior of various Gram-positive and Gram-negative bacteria.
• To explore the use of calcium ions (Ca2+) for modifying bacterial surface charge and reducing aggregation in capillary zone electrophoresis (CZE).

Main Methods:

• Capillary zone electrophoresis (CZE) was employed to analyze different bacterial strains.
• Surface charge modification was achieved using calcium ions (Ca2+).
• Electrophoretic analysis of bacterial aggregates was performed in an isotachophoretic mode.

Main Results:

• Calcium ions (Ca2+) increased bacterial zeta potential to over 2.0 mV, reducing repulsive forces.
• Ca2+ induced the formation of compact bacterial aggregates, leading to fewer high-intensity signals.
• A single peak was observed when analyzing bacterial aggregates using isotachophoretic CE.

Conclusions:

• Surface charge modification with Ca2+ effectively reduces bacterial aggregation in CZE.
• This method enables rapid analysis of bacteria with improved electrophoretic separation.
• The bridging effect of Ca2+ between bacterial cells is responsible for aggregate formation.