Physically and chemically cross-linked cellulose cryogels: Structure, properties and application for controlled...

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Cellulose is a versatile biopolymer with potential in drug delivery systems.
• Developing porous cellulose matrices with controlled swelling is crucial for effective drug release.
• Chemical cross-linking offers a method to tailor cellulose hydrogel properties.

Purpose of the Study:

• To prepare and characterize porous cellulose cryogels using epichlorohydrin cross-linking.
• To investigate the swelling behavior of cellulose cryogels as a function of cross-linker concentration.
• To evaluate the influence of cross-linking on cellulose matrix morphology and drug release kinetics.

Main Methods:

• Cellulose dissolution in NaOH-water followed by physical gelation.
• Chemical cross-linking using epichlorohydrin (ECH).
• Coagulation, lyophilisation, and characterization of cryogel morphology, crystallinity, and swelling.
• Drug release studies using procaine hydrochloride.

Main Results:

• Porous cellulose matrices were successfully prepared via a multi-step process.
• An anomalous high swelling ratio was observed at a specific epichlorohydrin concentration.
• Epichlorohydrin was proposed to act as a spacer, hindering cellulose chain packing during coagulation.
• The study characterized the morphology, crystallinity, and density of the cellulose cryogels.
• Drug release kinetics were investigated, showing dependence on the cross-linking density.

Conclusions:

• Chemical cross-linking with epichlorohydrin effectively modifies cellulose cryogel properties, particularly swelling.
• The observed anomalous swelling is attributed to the spacer effect of epichlorohydrin.
• These tailored cellulose cryogels demonstrate potential for controlled drug delivery applications.