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Pharmaceutical Applications of Carrageenan
Published in Amit Kumar Nayak, Md Saquib Hasnain, Dilipkumar Pal, Natural Polymers for Pharmaceutical Applications, 2019
A. Papagiannopoulos, S. Pispas
Chemical networks originating from blends of κ-carrageenan and polyvinyl alcohol (PVA) were cross-linked by genipin. The active material β-carotene was dispersed in ethanol and mixed with the polymer blend. The subsequent cross-linking was used to immobilize β-carotene within the network matrix. Genipin enhanced the physical stability of the hydrogels, eliminated the burst release of the drug, and controlled its diffusion (Hezaveh and Muhamad, 2013). In an earlier study, the influence of κ-carrageenan incorporated in agarose gels on the diffusion of drugs was investigated. Very interestingly, the hydrophobic part of the amphiphilic test drugs was varied. The diffusion coefficient of all six drugs was apparently the same in agarose gels while it reduced in the polysaccharidecontaining gels. In experiments of simultaneous diffusion of two drugs, the diffusion coefficient decreased to a much larger extent for the more hydrophobic drug in comparison to the less hydrophobic one. The authors put forward the possibility of exploiting hydrophobic cooperative effects in dual drug systems for controlled release in bi-phasic administration patterns (Sjöberg et al., 1999).
Pharmaceutical Applications of Gelatin
Published in Amit Kumar Nayak, Md Saquib Hasnain, Dilipkumar Pal, Natural Polymers for Pharmaceutical Applications, 2019
Vishal Girdhar, Shalini Patil, Sunil Kumar Dubey, Gautam Singhvi
Due to the observed cytotoxicity of glutaraldehyde, people have moved towards using naturally occurring agents for crosslinking of gelatin. One of these commonly used agents is genipin, obtained from Genipa americana and Gardenia jasminoides. This naturally occurring crosslinker is found to have the ability to easily crosslink with freely available amino groups, as in gelatin. Besides less cytotoxicity, it is also found to be biocompatible and thus, finds its application in tissue engineering, food industry, drug delivery, etc. (Cui et al., 2014).
Extracellular Matrix–Derived Biomaterials: Molecularly Defined Ingredients and Processing Techniques
Published in Gilson Khang, Handbook of Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine, 2017
H.R. Hoogenkamp, L.R.M. Versteegden, T.H. van Kuppevelt, W.F. Daamen
Since the majority of the natural ECM-derived biomaterials are protein or carbohydrate based, many of the developed crosslinking techniques are based on creating bonds between reactive groups like carboxylic groups and amines. Other reactive moieties include but are not limited to sulfhydryl, hydroxyl, and carbonyl groups. In general there are three types of crosslinking processes: physical, chemical, and enzyme-based crosslinking. Physical crosslinking methods rely on either irradiation or the use of high temperatures. Irradiation can induce free radicals that in turn react with other chemical groups nearby.399 Irradiative sources mainly refer to ultraviolet (UV) wavelengths but also to gamma and beta irradiation.399,400 Thermal sources in combination with high vacuum can be used to induce the dehydrothermal crosslinking, which allows for the formation of covalent bonds.401 Enzymatic crosslinkers like transglutaminase can be used to enhance tensile strength and enzymatic resistance of collagen-based biomaterials.402 One should take into account that the enzyme should also be inactivated and subsequently removed from the biomaterial in most cases. The use of enzymatic crosslinkers can eliminate the risk of inducing cytotoxic effects.403 The largest and most diverse group of crosslinkers are the chemical crosslinkers. Glutaraldehyde along with other aldehyde-based chemicals are the most applied chemicals to crosslink protein-based biomaterials.404 The carbodiimide family is another class of chemicals used to induce crosslinking.405 A key feature of this method is that some carbodiimides are categorized as zero-length crosslinkers. For example, 1-ethyl-3-(-3-dimethylaminopropyl carbodiimide hydrochloride (EDC) directly couples primary amine groups to carboxylic groups without introducing a linker that may elicit an immune response (see Fig. 28.10). A lesser known member of the chemical crosslinkers is the isocyanate chemical family.406 Recently, genipin, a chemical crosslinker derived from fruit extracts, has shown potential because of its low toxicity.407 In contrast to enzymatic crosslinkers, certain chemical crosslinking techniques can potentially form toxic residues or create crosslinks and subsequent metabolic products nonnative to the human body.408,409
Improved output force response speed of the biological gel artificial muscle prepared from carboxylated chitosan and sodium carboxymethyl cellulose
Published in Mechanics of Advanced Materials and Structures, 2023
Junyao Wang, Tianhong Lang, Huan Liu, Yansong Chen, Lixiang Li, Yahao Liu, Weihua Zhu
Nevertheless, most synthetic polymer gels were likely to pollute the environment because of poor degradability and biotoxicity. Fortunately, electro-responsive gels prepared from natural polymer materials make up for that. Thereinto, chitosan polymer with biocompatibility and biodegradability had been extensively employed to manufacture the ionic gel electric actuator [7–9]. Nonetheless, there are comparatively little researches on the influence of the artificial muscle’s structural size on the actuation performance. Thankfully, the influence of different thicknesses on the electromechanical properties of chitosan-based polymer actuators was considered [10]. In addition, chitosan modification via a cross-linking method can effectively improve the mechanical properties of ionic gel electric actuators [11]. Furthermore, a variety of crosslinking agents and crosslinking methods [12–14] were investigated to provide an essential reference for the crosslinking work of chitosan polymers. It is worth noting that among various crosslinking agents, Genipin has lower toxicity and better biocompatibility [15, 16].
Development and physicochemical analysis of genipin-crosslinked gelatine sponge as a potential resorbable nasal pack
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Jegadevswari Selvarajah, Mohd Fauzi Mh Busra, Aminuddin Bin Saim, Ruszymah Bt Hj Idrus, Yogeswaran Lokanathan
In this study, the effect of chemical crosslinker, genipin, towards gelatine sponge was analysed. Genipin, which originates from gardenia fruit extract, is a natural crosslinker that is considered to be one of the least cytotoxic crosslinkers to the cells [30, 59]. The main objective of crosslinking gelatine sponge is to compensate for the low mechanical properties and weak degradation resistance of the gelatine without compromising other physical and chemical characteristic of the gelatine sponge itself [32]. In accordance with the objective, the crosslinking of gelatine sponge with genipin does not alter the hydrophilicity, water vapour transmission rate, absorption capacity, and chemical bonding (FTIR analysis) of the gelatine sponge. In addition, the crosslinking of gelatine sponge with genipin influences the time of biodegradation and the porosity of the gelatine sponge. Previous reports support the notion that genipin crosslinking prolonged the biodegradation [39, 60] of biomaterial scaffolds. In the present study, an increase in the genipin concentration further decreases the rate of biodegradation of the gelatine sponge. Our results have demonstrated a similar trend to the previous findings, suggesting a decrease in the porous structure of the scaffold following treatment with genipin crosslinker [61,62]. However, although porous scaffold is more favoured for the haemostatic function, other essential characteristics such as absorption capacity and sponge degradation resistance must be taken into consideration when determining the best sponge blend for the nasal pack.
Preparation of gelatin/genipin nanofibrous membrane for tympanic member repair
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Longfei Li, Weizheng Zhang, Mengjia Huang, Jie Li, Jia Chen, Mi Zhou, Jianguo He
Gelatin is a protein with amino (NH2), carbonyl (CO), amide bond (CN) and other functional groups. Genipin is a cross-linking agent of iridoid with functional groups such as hydroxyl group (OH), carbon-carbon double bond (CC) and ester group (COO), which can react with amino group. The crosslinking reaction of genipin with gelatin is mainly composed of the following two steps (Scheme 1): Firstly, the amino group attacks the carbon atom of genipin to open the genipin ring and form aldehyde functional group. The amino group continues to react with the aldehyde group to finally form a relatively stable structure [42]. The second reaction is the formation of a three-dimensional network through the reaction of the ester and aldehyde structures with the amino groups on the gelatin [41,43].