Preparation and evaluation of lipid polymer nanoparticles for eradicating H. pylori biofilm and impairing antibacterial resistance in vitro.

The resistance of Helicobacter pylori to classical antimicrobial treatment has become increasingly common, whereupon biofilms are considered to play an important role in the resistance mechanism. Here 10.2% of amoxicillin (AMX) and a novel anti H. pylori adhesion material pectin sulfate (PECS) loaded lipid polymer nanoparticles (LPN) were prepared, with rhamnolipid and phospholipids as the outer mixed lipids layer (RHL-PC-LPN). The size of RHL-PC-LPN was around 200 nm, was negatively-charged, and showed sustained and complete drug release within 24h. In an in vitro study, H. pylori biofilm models were successfully established. RHL-PC-LPN, superior to PC-LPN (employing phospholipids only as the outer lipid layer), PECS+AMX (mixture of PECS and AMX) and AMX only, was proven to significantly eradicate H. pylori in the biofilm form. In accordance to our previous results, the RHL-PC-LPN group, together with the PC-LPN and PECS+AMX group, inhibited H. pylori from adhering to AGS cells. Investigating the underlying mechanisms contributing to the death of H. pylori caused by RHL-PC-LPN, we found that LPN could lower the antibiotic minimal inhibition concentration (MIC) to biofilm form from 125 μg/ml to 15.6 μg/ml. Furthermore, FITC-ConA labeled extracellular polymeric substances (EPS) were decreased in the RHL-PC-LPN group observed by a laser scanning confocal microscope. Therefore, we conclude that employing the mixed lipids of rhamnolipid and phospholipids as the outer layer of nanoparticles and PECS as the inner core produces a system capable of significantly disrupting H. pylori biofilm by eliminating the EPS as well as inhibiting the adherence and colonization of bacteria.