Application of chitosan–alginate microspheres for the sustained release of bacteriophage in simulated gastrointestinal conditions

Abstract

Summary This study was designed to evaluate the acid stability, release property and antimicrobial efficacy of Escherichia coli O157:H7 bacteriophages encapsulated in chitosan–alginate microspheres under the simulated gastrointestinal conditions. The bacteriophages belonging to Myoviridae family were stable at the pH above 4 in trypticase soy broth. The chitosan–alginate microspheres exhibited protective effect on the viability of bacteriophages in the simulated gastric conditions at pH 2.0 and pH 2.5, showing 4.8 and 5.6 log PFU mL‐1, respectively, after 1 h of incubation at 37 °C. The release per cent of bacteriophages from microspheres gradually increased up to 65% in the simulated intestinal condition (pH 7.5) at 37 °C for 6 h. The lytic efficacy of chitosan‐ and alginate‐encapsulated bacteriophages against E. coli O157:H7 was significantly maintained in the simulated intestinal conditions to 10 h of incubation (1.3 log reduction). The results suggest that the chitosan–alginate microspheres can be used as a reliable delivery system for bacteriophages.

Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release

“…Phage CDKM9 was shown to be highly sensitive to acidic pH. Similar results have been reported previously for a number of other therapeutic phages including a Salmonella phage Felix O1 (a myovirus) [31], a Staphylococcus aureus bacteriophage K (also a myovirus) [33], [37] and for an E . coli specific phage exposed for 5 min at pH 2 [33].…”

“…A limited range of microencapsulation techniques have previously been employed for bacteriophage encapsulation, with extrusion based droplet formation the most frequently used method [31], [33], [37], [60–64]. None have employed microfluidic fabrication techniques used here.…”

“…In a significant number of previously published studies, the sizes of phage encapsulated microparticles have tended to be considerably larger than those reported here (an order of magnitude bigger). Little consideration has previously been given to the control of the particle size distribution, the phage loading per particle and the resulting heterogeneity of the release kinetics from each particle [31–33], [37], [61]. A key advantage of the microfluidic fabrication process used here is the precision with which uniform small droplets (mean size ~100 μm) containing encapsulated phage may be prepared under low shear conditions resulting in near 100% phage encapsulation efficiency.…”

“…This is primarily due to the acidic conditions encountered in the stomach, and the presence of bile and digestive enzymes and other proteases in the intestinal tract and stomach [30–32]. Therefore, there is a clear need to protect phages against these adverse gastrointestinal conditions by encapsulating them [31–33], and to control their targeted release at the site of infection e.g. in the colon for CDI.…”

Preparation of micro-encapsulated strawberry fragrance and its application in the aromatic wallpaper

“…In general, natural macromolecular have the advantages of safety, nontoxicity, degradation and biocompatibility compared with synthetic macromolecule. The most commonly used natural macromolecules are chitosan, starch, dextrin and alginate [8][9][10][11][12][13] . Sodium octenylsuccinate is also called purity gum belonging to starch.…”