Bacterial medical applications

In some technological and medical applications protein adsorption and/or cell adhesion is advantageous, but in others it is detrimental. In bioreactors it is stimulated to obtain favourable production conditions. In contrast, biofilm formation may cause contamination problems in water purification systems, in food processing equipment and on kitchen tools. Similarly, bacterial adhesion on synthetic materials used for e.g. artificial organs and prostheses, catheters, blood bags, etc., may cause severe infections. Furthermore, biofilms on heat exchangers, filters, separation membranes, and also on ship hulls oppose heat and mass transfer and increase frictional resistance. These consequences clearly result in decreased production rates and increased costs. 

Medical applications of activated carbon adsorbents and purifying aids continue today. Examples of the many applications in current use include the use of activated carbons to adsorb bacterial toxins in the GI tract and in dialysis equipment for the purification of blood. 

The isolation, purification, and identification of nearly pure HA has been the center of scientific interest for many years. The bacterial production of HA by Streptococcus equi [182] and Streptococcus zooepidemicus [183] enabled it to be produced in larger quantities than could be achieved with extraction methods alone. HA produced by S. equi has a lower MW than does HA produced by S. zooepidemicus, which has a MW of about 1.8 to 2 x 106 Da with a yield of around 4 grams of HA per liter of the cultivated solution. At present, HA from various sources, with different degrees of purity and MWs, is available for medical applications. 

The kind of polysaccharides that are isolated from different bacteria are as follows Alginate, a linear copolymer with (l-4)-linked p-D-mannuronate and its a-L-guluronate residues that is produced by two bacterial genera Pseudomonas species and Azotobacter vinelandii [4]. Bacterial alginates are useful for the production of micro- or nanostructures suitable for medical applications. Cellulose, a p (1—>4) linked D-glucose unit obtained from Acetobacter xylinum. Cellulose of plant origin is usually impure as it contains... 

Currently cellulose (exopolysaccharide) and polyhydroxyalkonates are the most important bacterial polymers which can be profitably used as polymeric material for industrial and medical applications. But it seems to be particularly difficult to achieve a quantitative upgrading of the corresponding extraction, biotechnology and tailor-made synthesis for substantial production at lower prices. Hence, the exploitation of these polymers in various applications will be very difficult until this situation is resolved. Indeed, much awaited is the development of methodologies to increase production of these polymers at affordable prices for more utility. 

However, dissolved Cd " " ions have been known to bind to DNA and adsorb on membranes of bacterial cells (92). Cellular response (cell viability, gene expression) to QD exposure is highly dependent on QD surface functionalization and capping, particle size, and the nature of the biofilm (97-99). Prehminary research concludes that the biophysiochemical interactions between biofilms and QDs must be understood before biological testing for medical applications can be accurately interpreted (100). 

Bacterial polyesters (polyhydroxy alkanoates) Poly(3-hydroxy butyrate), poly(3-hydroxy valerate) Some micro-organisms, especially bacteria, can synthesise biocompatible aliphatic polyesters, which have potential in medical applications. 

Zinn M, Witholt B, EgU T (2001) Occurrence, synthesis and medical application of bacterial polyhydroxyalkanoate. Adv Drug Deliv Rev 53 5-21 Zong X, Bien H, Chung C-Y, Yin L, Fang D, Hsiao BS, Chu B, Entcheva E (2005) Electrospun fine-textured scaffolds for heart tissue constructs. Biomaterials 26 5330-5338... 

Nanocellulose, such as that produced by the bacteria Gluconacetobacter xylinus (bacterial cellulose, BC), is an emerging biomaterial with great potential in several applications. The performance of bacterial cellulose stems from its high purity, ultra-fine network structure and high mechanical properties in the dry state [114]. These features allow its applications in scaffold for tissue regeneration, medical applications and nanocomposites. A few researchers have used bacterial cellulose mats to reinforce polymeric matrices and scaffolds with wound healing properties [115-121]. BC is pure cellulose made by bacterial fabrication via biochemical... 

Cienchanska, D. Multifunctional bacterial cellulose/chitosan composite materials for medical applications. Fibres Text. East Eur. 12, 69-72 (2004)... 

Medical Application of Bacterial Cellulose 10.5.1 Human Medicine... 

Zinn, M., Witholt, B. and EgU, T. (2001) Occurrence, synthesis and medical application of bacterial polyhydroxyalkanoate. Advanced Drug Delivery Reviews, 53, 5-21. 

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