Vision of bacterial ghosts as drug carriers mandates accepting the effect of cell membrane on drug loading

Abstract

The use of bacterial ghosts (BGs) for drug delivery is an extremely fascinating perspective especially with the inherited efficient target-ability to specialized tissues. Trafficking of drug molecules across the outer membrane of Gram-negative bacteria are important to be understood for both loading (influx) and drug release (efflux). In this study, Escherichia coli (E. coli) BGs were prepared using modified protocol sponge-like reduced protocol (SLRP) which was used for loading of doxorubicin (DOX). First time in the literature, different possible factors affecting DOX loading from BGs were examined in this study. These factors including drug concentration, temperature, pH gradient, incubation time and tonicity, are proposed to effect on drug loading into E. coli BGs. Results of optimum effect from accompanied factors were found to be 10 mg/mL as DOX concentration at pH 6 with tonicity of 0.7% incubated overnight at 4 °C. After gather all factors, the amount of DOX loaded inside the BGs was recorded as 37.58%. The in vitro release studies of DOX loaded BGs over time showed a burst initial release rate of 26.75% at the first 12 h followed by a period of sustained release lasting for 16 days to give maximum release rate of 58.04%. Remarkably, DOX loaded in BG showed more apoptosis (55%) than control and DOX solution. Overall, the results indicated the presence of some important factors to be controlled when loading drugs into BGs. Also, data showed the future possibility of utilizing BGs to deliver DOX to colon cancer cells.