Although either the interactions of Escherichia coli with the polymer chains, or the extracellular environment altered the self-assembly process, resulting in filled microparticles (Figure ), we could observe spatial association of the bacteria with the polymer and encapsulation of the bacteria within the polymer structures. Importantly, the live/dead assay for bacteria showed a good viability (~70%) of these cells despite the use of an oxygen-free buffer that furthermore did not contain any nutrients and was rich in bromide ions, suggesting the biocompatibility of bioPISA (Figure ).