Development of electrospun nanofibers that enable high loading and long-term viability of probiotics

The interest in probiotics has grown in recent years due to increased awareness of the importance of microbiota for human health. We present the development of monolithic poly(ethylene oxide) and composite poly(ethylene oxide)/lyoprotectant nanofibers loaded with the probiotic Lactobacillus plantarum ATCC 8014. High loading was achieved for L. plantarum cells (up to 7.6 × 10⁸ colony-forming unit/mg) that were either unmodified or expressing mCherry fluorescent protein. The initial concentration of L. plantarum in poly(ethylene oxide) solution was reported, for the first time, as the most critical parameter for its high viability after electrospinning, whereas the applied electric voltage and relative humidity during electrospinning did not vitally impact upon L. plantarum viability. The presence of amorphous lyoprotectant (especially trehalose) in the nanofibers promoted L. plantarum survival due to lyoprotectant interactions with L. plantarum cells. L. plantarum cells in nanofibers were stable over 24 weeks at low temperature, thereby achieving stability comparable with that in lyophilizates. The poly(ethylene oxide) nanofibers released almost all of the L. plantarum cells over 30 min, which will be adequate for their local administration. Our integrated approach enabled development of a promising nanodelivery system that provides high loading and long-term viability of L. plantarum in nanofibers, for local delivery to re-establish the microbiota balance e.g. in vagina.