Starch Nanocarriers for Enhanced M-Cell Transport and Oral Delivery of Bioactive Proteins

To improve the resistance to the harsh environment of the gastrointestinal tract (GIT) and the efficiency of specific binding and uptake by intestinal epithelial cells, the GRGDS-conjugated carboxymethyl starch (R-CMS) carrier was designed and the delivery system, which can enhance M-cell transport for bioactive proteins, was developed. FTIR, 1 H NMR, and elemental analysis verified that GRGDS can be successfully introduced. CLSM results indicated that R-CMS shows good targeting ability to M cells. The formation of ovalbumin (OVA)-loaded nanocapsules was driven by hydrogen bond and electrostatic interactions between negatively charged R-CMS and positively charged starch. The nanocapsules were compact in structure and the Z -average diameter was only 158.8 ± 6.58 nm, and they were relatively stable under different storage conditions. Furthermore, only 44.03% of the loaded OVA were leaked out before the fabricated nanocapsules reached the M cells during GIT delivery and the bioaccessibility of OVA was improved because the arrived nanocapsules showed higher specific binding ability and transport efficiency to M cells. Accordingly, these findings would provide a promising pathway for the development of the oral delivery system for bioactive proteins through a starch-based material that improves the targeting and transport efficiency to M cells.