A zwitterionic serine modified chitosan derivative for improving protein stability and activity

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biochemistry

Background:

• Chitosan is a biocompatible polysaccharide with potential in biomedical applications.
• Modifying chitosan with zwitterionic groups can enhance its properties.
• Phosphoryldiserine (PDS) is a zwitterionic molecule that can be conjugated to polymers.

Purpose of the Study:

• To synthesize and characterize a zwitterionic phosphoryldiserine (PDS)-chitosan conjugate.
• To evaluate the cell compatibility and protein stabilization capabilities of the synthesized conjugate.
• To explore the potential of PDS-chitosan in maintaining protein function for biomedical uses.

Main Methods:

• Synthesis of PDS-chitosan conjugate via Atherton-Todd reaction.
• Characterization using NMR, ICP, FTIR, and XRD.
• In vitro cytotoxicity and hemolysis assays.
• UV-Vis adsorption and fluorescence spectroscopy to assess protein conformation and stability.
• Enzyme activity assays to evaluate protein function.

Main Results:

• Successful synthesis and structural characterization of PDS-chitosan conjugate.
• Confirmation of freezing bound water due to PDS incorporation, enhancing thermal properties.
• Excellent in vitro cell compatibility and low hemolysis.
• Demonstrated ability of PDS-chitosan to maintain native conformation and thermal stability of model protein bovine serum albumin (BSA).
• Enhanced esterase-like activity of BSA at low PDS-chitosan concentrations.

Conclusions:

• Zwitterionic PDS-chitosan conjugate exhibits superior biocompatibility and cell compatibility.
• PDS-chitosan effectively preserves protein native structure and enhances thermal stability.
• The conjugate shows potential for improving protein function, indicating significant promise for biomedical applications.