Changing Cinnamaldehyde Skeleton Achieves Antibacterial Nanoswitch.

Area of Science:

• Organic Chemistry
• Materials Science
• Nanotechnology

Background:

• Understanding the antibacterial mechanisms of organic molecules is crucial but challenging.
• Modifying substituent groups can tune electron cloud density, potentially controlling biological activity.
• Cinnamaldehyde and its derivatives offer a scaffold for investigating structure-activity relationships.

Purpose of the Study:

• To develop a molecular strategy for clarifying the antibacterial switch mechanism by tuning electron cloud density.
• To synthesize cinnamaldehyde derivatives into water-soluble nanosheets.
• To investigate the antibacterial activity and biocompatibility of these nanosheets.

Main Methods:

• Self-assembly of cinnamaldehyde derivatives into nanosheets.
• Evaluation of antibacterial activity of α-bromocinnamaldehyde (BCA) and α-methylcinnamaldehyde nanosheets.
• Theoretical calculations to correlate electron cloud density with antibacterial activity.
• Biocompatibility assessment using CCK-8 assay.
• In vivo testing using a mouse wound infection model and Drosophila larvae model.

Main Results:

• BCA nanosheets exhibited significant antibacterial activity, whereas α-methylcinnamaldehyde nanosheets showed none, establishing an antibacterial switch.
• Theoretical calculations confirmed that the electron-withdrawing bromine substituent lowers electron cloud density, crucial for antimicrobial activity.
• BCA nanosheets demonstrated excellent biocompatibility and safety in both in vitro and in vivo models.
• The material showed promise for wound healing applications.

Conclusions:

• Tuning electron cloud density via substituent modification is an effective strategy for controlling antibacterial activity.
• BCA nanosheets represent a safe, biocompatible, and low-cost organic nanomaterial with potential as an antimicrobial agent for wound healing.
• This approach provides a new avenue for developing organic nanomaterials from natural small molecules.