Synthesis and characterization of curdlan/β-cyclodextrin composite hydrogels for sustained-release

Enhancement of gel characteristics of curdlan thermo-irreversible gels by β-cyclodextrin and its possible mechanisms

In this study, the influences of various concentrations of β-cyclodextrin (β-CD) on the gelation properties of curdlan thermo-irreversible gels were evaluated. The results revealed that water-holding capacity and freeze-thaw stability of the curdlan/β-CD complex gels initially increased but then decreased with increasing β-CD concentration, with the curdlan gel containing 1 % (w/v) β-CD demonstrating the best performance. Moreover, textural characteristics including hardness, gumminess, cohesiveness, and chewiness exhibited similar trends, but springiness showed minor effect. Compared with the pure curdlan gel, the curdlan/β-CD mixed gels exhibited better elastic behavior and greater thermal stability but lower crystallinity. Additionally, scanning electron microscopy (SEM) images of the curdlan/β-CD composite gels revealed fine network structures with relatively continuous pores. The intermolecular hydrogen bonds between curdlan and β-CD were responsible for the enhanced gel properties. Thus, these data suggest that the inclusion of β-CD ameliorates the texture and stability of the curdlan gel by forming hydrogen bonds.

Cyclodextrin regulated natural polysaccharide hydrogels for biomedical applications-a review

Cyclodextrin and its derivative (CDs) are natural building blocks for linking with other components to afford functional biomaterials. Hydrogels are polymer network systems that can form hydrophilic three-dimensional network structures through different cross-linking methods and are developing as potential materials in biomedical applications. Natural polysaccharide hydrogels (NPHs) are widely adopted in biomedical field with good biocompatibility, biodegradability, low cytotoxicity, and versatility in emulating natural tissue properties. Compared with conventional NPHs, CD regulated natural polysaccharide hydrogels (CD-NPHs) maintain good biocompatibility, while improving poor mechanical qualities and unpredictable gelation times. Recently, there has been increasing and considerable usage of CD-NPHs while there is still no review comprehensively introducing their construction, classification, and application of these hydrogels from the material point of view regarding biomedical fields. To draw a complete picture of the current and future development of CD-NPHs, we systematically overview the classification of CD-NPHs, and provide a holistic view on the role of CD-NPHs in different biomedical fields, especially in drug delivery, wound dressing, cell encapsulation, and tissue engineering. Moreover, the current challenges and prospects of CD-NPHs are discussed rationally, providing an insight into developing vibrant fields of CD-NPHs-based biomedicine, and facilitating their translation from bench to clinical medicine.

Hydrogels Consisting of Vesicles Constructed via the Self-Assembly of a Supermolecular Complex Formed from α-Cyclodextrin and Perfluorononanoic Acid

The self-assembly of α-cyclodextrin (α-CD) mixed with a fluorocarbon surfactant, perfluorononanoic acid (PFNA), in aqueous solution was studied. Interestingly, the 1:1 inclusion complex, PFNA@α-CD, was verified to form by ¹H nuclear magnetic resonance measurement. Also as the building block, the PFNA@α-CD complex was further self-assembled into worm-like micelles under lower concentrations while hydrogels were self-assembled under higher concentrations. The hydrogels were composed of unilamellar vesicles with polydisperse size, which were clearly detected by freeze-fracture transmission electron microscopy measurements. Besides, the vesicle hydrogels showed high viscoelasticities and a substantial elastic characteristic. Also as revealed by the results of Fourier transform infrared measurements, the driving force for the vesicle and worm-like micelle formation was the hydrogen bonding between α-CD molecules. Then, these vesicles were densely packed to form hydrogels. As far as we know, the self-assembly of CDs and fluorocarbon surfactants based on host-guest inclusion in aqueous solution has been limitedly reported. Our work successfully constructed hydrogels consisting of vesicles through the self-assembly of the α-CD/PFNA complex for the first time and will also provide a better understanding and enrich the fundamental research of the self-assembly behavior of the CD/fluorosurfactant complex.