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Poster De Conférence Année : 2024

Starch aerogels, cryogels and xerogels for biomedical applications

Résumé

Introduction: Starch is one of the most abundant natural polysaccharides which can be found, for example, in corn, potato, wheat and rice. It consists of two main polymers, linear amylose and branched amylopectin, in a ratio that depends on the plant type. Porous starch materials have shown great promise for several biomedical applications, including tissue engineering and drug delivery.1 Each application requires a specific morphology, density, internal pores’ surface area and pore size distribution. It is thus important to understand morphology development during processing and to correlate it with final material properties as it allows for the design of biomaterials with tailored characteristics and the desired in vitro and in vivo behavior. In this contribution, examples of porous starch biomaterials are discussed that have been developed in our lab. Experimental Methods: Potato starch was dissolved in water via thermomechanical treatment. Retrogradation at 4 °C resulted in the formation of hydrogels. To obtain starch aerogels, water in hydrogels was replaced by a non-solvent (ethanol or acetone), followed by drying with supercritical CO2. Cryogels were prepared via freeze-drying of starch hydrogels. Xerogels were made via evaporative drying of organogels under low vacuum. The model drug theophylline was loaded via impregnation. The influence of various process parameters on material density, specific surface area, morphology and drug release was investigated. Results and Discussion: The density of the starch biomaterials ranged from 0.05 g/cm3 for cryogels to 0.4 g/cm3 for aerogels and xerogels. The starch concentration and the retrogradation time were the main parameters to control density. The specific surface area varied between 20 m2/g (cryogels) to 120 m2/g (aerogels and xerogels) and was mainly determined by the non-solvent and retrogradation time in the case of aero- and xerogels. Cryogels contained macropores due to the sublimation of ice crystals, whereas aerogels and xerogels had smaller meso- and macropores, in line with their higher specific surface area. Compression tests on aero- and xerogel samples revealed Young’s moduli between 10 and 20 MPa, with a higher density leading to a higher modulus. Theophylline release profiles from aerogels and xerogels were similar with a fast initial release followed by a slow approach to full release.2 Conclusions: The results imply that vacuum drying is an appealing alternative to the more expensive and laborious scCO2 drying, as it results in aerogel-like starch materials with potential use as drug delivery systems.
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Dates et versions

hal-04659189 , version 1 (22-07-2024)

Identifiants

  • HAL Id : hal-04659189 , version 1

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Hiba Bouras, Fangxin Zou, Yannick Tillier, Sytze Buwalda, Tatiana Budtova. Starch aerogels, cryogels and xerogels for biomedical applications. Advanced Functional Polymers for Medicine 2024, Jun 2024, Utrecht, Netherlands. . ⟨hal-04659189⟩
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