IMMOBILIZATION OF BIOACTIVE PROTEINS ON SOLID SUPPORTS : APPLICATIONS TO FOOD PACKAGING AND FOOD NANOTECHNOLOGY
Tesi di Dottorato
Data di Pubblicazione:
2009
Citazione:
IMMOBILIZATION OF BIOACTIVE
PROTEINS ON SOLID SUPPORTS :
APPLICATIONS TO FOOD PACKAGING
AND FOOD NANOTECHNOLOGY / M. Marengo ; F. Bonomi. DIPARTIMENTO DI SCIENZE MOLECOLARI AGROALIMENTARI, 2009 Dec 10. 22. ciclo, Anno Accademico 2008/2009.
Abstract:
Much of the interest concerning bioactive protein immobilization onto solid supports can be attributed to the many potential applications protein-modified surfaces may
have in the area of biotechnology. Immobilized bioactive proteins (e.g. antibodies, enzymes) have been used in countless immunoassays, as well as in clinical analysis and diagnostics, in
biosensors, and in various industrial applications, including food processing.
In this frame, this PhD thesis research project aimed at developing strategies to
immobilize food-relevant bioactive proteins onto various solid supports, and at exploiting the interactions between the proteins and the solid matrices considered in this peculiar project to design either innovative packaging materials or novel nanotech-based analytical tools. Within the overall objective mentioned above, this project was subdivided into the
following activities: 1. preparation of an antimicrobial biodegradable packaging material by binding lysozyme onto papers opportunely modified with polyelectrolytes; 2. preparation of biofunctionalized magnetic nanoparticles by binding specific food
bioactive proteins to a conveniently activated dextran coating on the particle
surface, for cellular targeting of conjugates; 3. preparation of magnetic nanotracers for addressing molecular recognition events, and use of the nanotracers to improve current analytical protocols. Novel food processing and new packaging strategies are being developed as a
response to both consumer demand for and industrial trends towards mildly preserved, tasty, and convenient food products with prolonged shelf-life and controlled quality. Globalization of the food trade and recent food-borne microbial outbreaks are driving forces in the search for innovative ways to inhibit microbial growth in foods while maintaining quality, freshness, and safety. In this frame, one of the most innovative developments in the area of food packaging is the design of antimicrobial biopolymer-based active packaging materials incorporating biocides into or onto the surface of polymers themselves. In our studies, we addressed the interactions between charged polysaccharides and lysozyme, monitoring the protein structural changes and rearrangements consequent to noncovalent bonds with the polysaccharides. Lysozyme was incubated for different times and at different temperatures with soluble carboxy-methyl cellulose (CMC), and polygalatturonic acid (PGA), in the presence/absence of salts (NaCl), non-ionic chaotropes (urea), and anionic detergents (sodium dodecyl sulphate). The various systems were then analysed by a number of spectroscopic methodologies that demonstrated that the charged polyelectrolytes do not impair the structural and functional properties of lysozyme. Tryptophan fluorescence measurements showed that soluble CMC improves the thermal stability of the tertiary structure of lysozyme above 60°C, and has little if any effect on the stability of its secondary structure, as demonstrated by far-UV circular dichroism measurements. This data paved the way to the addition of CMC and PGA to paper-based packaging materials intended to incorporate lysozyme as antimicrobial not only because this improves the incorporation yield (mainly due to electrostatic interactions) and allows modulation of protein release, but
also because it results in stabilization and preservation of the protein structure and activity during drying at 100°C, mimicking the heating steps in the paper making process itself, and would likely prolong the operative shelf-life of the resulting active packaging. The second part of this project dealt with the preparation of nanotechnological food-related applications. Nanotechnology is an emerging multidisciplinary field of applied
scien
Tipologia IRIS:
13 - Tesi di dottorato discussa entro ottobre 2010
Keywords:
nanobiotechnology ; magnetic nanoparticles ; bioactive proteins ; protein immobilization ; human monocytes
Elenco autori:
M. Marengo
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