Bioactive molecule incorporation

Beyond the complete assembly of biomimetic membranes, interfacial supramolec-ular assemblies which incorporate biocomponents represent an important approach to replicating the biological functions outside of living systems. For example, the ability to link or wire otherwise electro-inactive enzymes to electrodes so that they can efficiently transport electrons allows sensitive and selective sensors to be developed for important bioactive molecules, e.g. glucose, lactate, urea, etc. 

At the heart of any search for bioactive molecules is the need for effective bioassays. Several bioassays have been developed for the identification of compounds with anti-juvenile hormone (AJH) activity. The most common of these AJH bioassays involves the treatment of young larvae or nymphs with the potential AJH by incorporation into the diet or contact application, and then waiting for several days (or, in some cases, weeks) for precocious development (or other AJH response) to occur ( 1, ). Alternatively, AJH activity can be determined using jri vitro assays such as corpora allata cultures or epidermal cell cultures to monitor for inhibition of juvenile hormone (JH) biosynthesis (3-6) or blockage of the JH induced inhibition of pupal commitment (7), respectively. 

Incorporation of bioactive molecules into PAn is not so readily achieved because electropolymerization must normally be carried out at low pH. However, thin polymeric coatings containing enzymes have been produced by polymerization from buffer solutions (pH = 7).45 Tatsuma and coworkers46 have immobilized... 

Modification or functionalisalion of nanofibres is the important trend in the development of nanofibrous structures for biomedical applications, in order to engineer specific features that will help maximise their end use performance. A spectrum of bioactive molecules, including antibacterial agents, anti-cancer drugs, enzymes and proteins, can be incorporated into nanofibres via dlHerent approaches. 

It is also possible to incorporate bioactive molecules (eg. Ab s, enzyme) into conducting polymers (10, 11). The production of stand alone membranes incorporating bioactive molecules is the subject of ongoing woik in our laboratories. 

With a typical size ranging from nanometric (<100 nm) to submicrometric (<1 pm), biopolymeric particles and nanoparticles, made of proteins or polysaccharides, thanks to their excellent compatibility with foods, are able to efficiently encapsulate, protect and deliver bioactive compounds, forming different structures, such as random coils, sheets, or rods around the bioactive molecules. The most suitable biopolymers for the incorporation into foods include (1) proteins, such as whey proteins, casein, gelatin, soy protein, zein, and (2) polysaccharides, such as starch, cellulose, and other hydrocolloids, with the particle formulation depending on the desired particle functionality (size, morphology, charge, permeability, environmental stability), on end product compatibility and in general in product behavior, as well as on release properties and in body behavior. 

Liquid crystalline phases are also of interest from the point of view of controlled or sustained release, or even the absence (e.g. in the case of certain potent enzymes) of such release of bioactive molecules. For example, due to the presence of both water and oil channels in bicontinuous cubic structures, such systems are capable of solubilizing both hydrophilic, hydrophobic and amphiphilic drugs, the release of which can be sustained over extended periods of time. Particularly interesting in this respect is the incorporation of large oligopeptide or macromolecular drugs (e.g. enzymes). For example, Ericsson et al. investigated the incorporation of lysozyme in a cubic phase formed by monoolein and water, and found that a considerable amount could be solubilized in the liquid crystalline phase (182). Furthermore, the incorporation of c -lactalbumin, bovine serum albumin and pepsin was found to resemble that... 

The most convenient, and hence most popular, approach to confer biospecificity to CEP layers is via incorporation of naturally derived bioactive molecules. For this purpose, the methods outlined in the previous section have been widely utilized. However, the use of recombinants specifically engineered for advantage in immobilization within CEPs is currently developed. 

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