Single-Cell Oral Delivery Platform for Enhanced Acid Resistance and Intestinal Adhesion

Area of Science:

• Biomaterials Science
• Drug Delivery
• Microbiology

Background:

• Oral delivery of cells like probiotics and vaccines is inefficient due to stomach acidity and poor intestinal retention.
• Existing methods struggle to protect therapeutic cells during gastric transit and ensure prolonged intestinal presence.

Purpose of the Study:

• To develop a novel cell-in-shell structure for enhanced oral delivery of cells.
• To create a delivery system with pH-responsive and mucoadhesive properties to overcome limitations of oral cell administration.

Main Methods:

• A layer-by-layer (LbL) assembly technique was used to create a pH-responsive shell using chitosan and trans-cinnamic acid (t-CA).
• The shell's properties were tested using probiotic *L. rhamnosus* GG and inactivated *Streptococcus iniae* vaccine cells.
• Gastric resistance, intestinal retention, and antigen exposure after acid treatment were evaluated.

Main Results:

• The cell-in-shell structure demonstrated enhanced gastric resistance and improved intestinal retention compared to naked cells.
• Partial removal of the coating (20-60%) post-acid treatment allowed for exposure of immunogenic proteins.
• Increased survival and retention of coated cells were observed during oral administration.

Conclusions:

• The designed cell-in-shell structure is a promising smart oral delivery platform for cells and macromolecules.
• This strategy enhances cell survival and efficacy in the intestine, offering a new approach for oral vaccines and probiotics.
• The system can be adapted for various macromolecules, potentially revolutionizing oral disease prevention and treatment at a cellular level.