Functionalisation biodegradation

Related to ionic liquids are substances known as deep eutectic solvents or mixtures. A series of these materials based on choline chloride (HOCH2CH2NMe3Cl) and either zinc chloride or urea have been reported (Abbott et al., 2002 2003). The urea/choline chloride material has many of the advantages of more well-known ionic liquids (e.g. low volatility), but can be sourced from renewable feedstocks, is non-toxic and is readily biodegradable. However, it is not an inert solvent and this has been exploited in the functionalisation of the surface of cellulose fibres in cotton wool (Abbott et al, 2006). Undoubtedly, this could be extended to other cellulose-based materials, biopolymers, synthetic polymers and possibly even small molecules. 

Control over release rates from mesoporous surfactant templated particles has been obtained by several methods. The size and connectivity of the pore system as well as particle size and shape are of prime importance. Simple organic functionalisation on the external and internal surfaces of the particles ° or preparing hybrid particles in thermo-responsive hydrogels, " biodegradable polymers " or collagen " can affect release rates. Polymer layers have also been used to determine entrance of particular species into pores for sensor purposes. 

With respect to hotmelts, biobased and biodegradable (Guo et al., 2010) types are available on the market, developed primarily for paper and cardboard. Table 1.8 gives an overview of hotmelts tested on textiles. Some were functionalised towards antimicrobial behavior and fire resistance (De Vilder et al., 2013). On cotton, good flame retardancy was obtained for the FR-functionalized Unirez using Eco-flam PU-228... 

Biodegradable polymeric nanoparticles have been prepared and used to enhance the stability of proteins and peptides, control their release and pharmacokinetic parameters, furthermore, to improve their bioavailability. For delivery purposes, the polymeric material needs to meet physicochemical and biological requirements, of which, biocompatibility, safety, and biodegradability into non-toxic metabolites are of cmcial importance. The polymers can be easily functionalised towards off opsoni-sation. They are also known to show reduced toxicity in the peripheral healthy tissues. The selection of polymers depends on the method of administration, the bioactive molecules to be loaded, the desired release profile, the intention to target specific tissues, the desired rate of particle degradation, and the biocompatibility. Table 11.3 outlines some of the natural and synthetic polymers currently used in the fabrication of nanoparticles. 

Chitosan, a naturally occurring polysaccharide, is biocompatible, bioresorbable, biodegradable, and has mucoadhesive properties (Ilium, 1998). The polysaccharide hydroxyl and theamine groups can be easily functionalised under mUd reaction conditions to prepare modified chitosan derivatives with altered, desirable properties. 

Surface functionalisation of biodegradable polylactic acid was achieved by plasma coupling reaction of chitosan. Surfaces were characterised by contact angle measurements and X-ray photoelectron spectroscopy. Two cell lines were cultured on the modified surface. Potential applications in tissue engineering are mentioned. 36 refs. CHINA SINGAPORE Accession no.906871... 

Chitin and its deacetylated derivative chitosan are suitable bioplatforms that can be further improved by targeted functionalisation for skin repair. For example, the unique biological properties of chitosan characterised with human cell biocompatibility, human serum biodegradability, non-toxicity, antibacterial and haemostatic properties justify the use of this biopolymer in skin repair processes. The haemostatic activity of chitosan is exploited in early treatment of wounds [28], especially in large injuries subjected to heavy bleeding [29]. Many haemostatic products on the market consist thus, fully or partially, of chitosan. Moreover, chitosan aids to a rapid closure of fuU-thickness wounds due to its supportive effect to the fast growing of new blood vessels (angiogenesis) in the injured tissue [30]. Chitin and chitosan can be... 

---