A METHOD FOR MAKING SPATIALLY DEFINED AGGREGATES BY PRECISELY POSITIONING CELLS BASED ON ELECTROSTATIC INTERACTION

摘要

The present invention relates to cell aggregation and particularly, although not exclusively, to microbial or bacterial cell aggregation. The invention is a method for making spatially defined aggregates by precisely positioning cells based on electrostatic interaction, the method comprising the steps of:a. surface modification of a first portion of cells to obtain cells with a positive surface potential (i.e. first cells), said modification comprising:- growing cells in a suitable growth medium to a suitable OD, washed and optionally treated to break any existing multicellular structures caused by spontaneous flocculation, coagulation or aggregation of cells,- treatment of suspension of dispersed cells obtained in the previous step with a 0.025 to 0.25% w/v solution of a positively charged polyelectrolyte to form a first portion of surface modified cells; and removing excess polyelectrolyte, not associated with cells, out from the suspension,b. forming aggregates of cells by mixing the first portion of surface modified cells with a second portion of cells with a negative surface potential (i.e. second cells) to form aggregates comprised of first cells covered with a layer of second cells, said aggregates having a negative surface potential, or aggregates comprised of second cells covered with a layer of first cells, these aggregates having a positive surface potential.