Tracking Bacterial Nanocellulose in Animal Tissues by Fluorescence Microscopy

Area of Science:

• Food Science
• Nanotechnology
• Toxicology

Background:

• Nanomaterials offer potential in food technology, but require rigorous safety assessments.
• Bacterial nanocellulose (BNC), a food product in Asia, necessitates toxicological evaluation due to its nano-scale properties.
• Assessing gastrointestinal absorption of nanoparticulate cellulose is crucial for regulatory approval.

Purpose of the Study:

• To develop and assess a screening technique for detecting bacterial cellulose nanocrystals (BCNC) in biological tissues.
• To evaluate the potential absorption of BNC and BCNC in the gastrointestinal tract.
• To investigate the safety of BNC as a food additive.

Main Methods:

• Developed a detection method using a green fluorescent protein-BNC-binding module (GFP-CBM) for BCNC.
• Utilized correlative electron light microscopy to visualize BCNC.
• Conducted a 21-day repeated-dose study in Wistar rats feeding on BNC.

Main Results:

• The GFP-CBM technique successfully detected isolated BCNC using fluorescence microscopy.
• BCNC were observed within macrophages, indicating cellular uptake.
• No BNC or BCNC were found beyond the intestinal lumen in rats, suggesting no systemic absorption.

Conclusions:

• BNC and BCNC appear to remain within the intestinal lumen, indicating they are not absorbed systemically.
• The developed GFP-CBM method is a viable tool for detecting nanocellulose particles.
• These findings support the safety of BNC as a food additive, pending further toxicological studies.