O2 -requiring molecular reporters of gene expression for anaerobic microorganisms

Many genetic reporter systems require molecular oxygen; therefore, the use of reporter genes to study molecular mechanisms in anaerobic microorganisms has been hampered by the lack of convenient reporting systems. We describe reporter gene whole cell-based biosensor systems based on luciferase genes and the associated oxygen-requiring enzymes. By using two different oxygen-dependent reporters, insect and bacterial luciferases, and two bacterial hosts, Gram (+) Bifidobacterium longum and Gram (-) Escherichia coli, we show that the enzymes can be used in gene expression studies of anaerobic bacteria. E. coli, a facultative anaerobe, was grown both in aerobic and anaerobic conditions with an arabinose-inducible expression system. We show that a short treatment time of few minutes in ambient atmosphere is sufficient to detect light emission from living cells that is directly proportional to the number of cells and to the inducer concentration. The induction levels were the same in both the aerobically and anaerobically cultured cells. Similar results were obtained in the case of B. longum cultured in anaerobic conditions

High resolution E-jet printed temperature sensor on artificial skin

Skin-conformable electronics research field has grown rapidly during the recent years. Body monitoring systems are shrinking in size and integrating more seamlessly with the human skin. To make these monitoring systems feasible options, new suitable materials and manufacturing processes needs to be studied. This paper presents materials and a simple fabrication process for skin-conformable, E-jet printed silver temperature sensors. Utilizing printing processes and biodegradable substrate materials, the skin-conformable electronics may become attractive for disposable systems by decreasing the manufacturing costs and reducing the amount of waste materials. In this study, the temperature sensors are fabricated with E-jet printed silver nanoparticle ink and the printing is done on a bacterial nanocellulose substrate. During the characterization, the silver temperature sensors were able to reach more than 0.06 % resistance change per degree Celsius sensitivity and they exhibited positive temperature dependence.acceptedVersionPeer reviewe

Sustainable preparation of immobilized (bio)catalysts for heterogeneous stereoselective transformations

Bacterial cellulose (BC) is an exopolysaccharide synthesized by various species of bacteria. Its increasing interest lies in higher purity and cristallinity over the plant cellulose, which determines also better mechanical properties; for these reasons BC is used in \u201chigh-end\u201d markets such as in pharmaceuticals and medical applications (in wound healing and as drug carrier), in acoustic speakers production, in biosensors making. BC is mainly produced by fermentation employing strains belonging to Komagataeibacter genus (K. xylinus) and different carbon sources/growth conditions combinations. In this work we present the results obtained using modified (both in terms of particle size and chemical derivatization) BC as support for different kind of catalysts (enzymes such as esterases, ketoreductases and porphyrins-derived heterogeneous catalysts), in the transformation of various molecules of synthetic interest. The sustainable production of BC is achieved with high-producers recombinant strains of Komagataeibacter xylinus, using biomasses ( cladodes of Opuntia sp.) and industrial food-wastes (cheese-whey and citrus waste) as feedstocks

Bionanomaterial thin film for piezoelectric applications

Wearable and flexible electronics are becoming of recent interest due to expansion of Internet of Things (IOT). Thin film piezoelectric materials have the potential to be used as the development of flexible electronic devices in energy harvesting, sensing and biomedicine. This is mainly be-cause of the inherent ability of piezoelectric materials to convert the mechanical energy to the electrical energy or vice versa. Piezoelectricity in material represents the property of certain crys-talline structure that is capable to developing electricity when pressure is applied. However, con-ventional piezoelectric materials such as PZT (lead zirconate titanate) and PVDF (poly(vinylidene flouride)) are expensive, non-renewable, non-biodegradable and lack of biocom-patibility due to the cytotoxicity nature of lead-based material. Piezoelectric material from natu-ral polymers of biomaterial may provide the solutions for the drawbacks of piezoceramics and piezoelectric polymers. This review emphasis is on the piezoelectricity of various bionanomaterials (cellulose, chitin, chitosan, collagen, amino acid and peptide). The various methods used to measure piezoelectricity of biomaterials is also discussed. This study shows that biomaterials have the potential to be used as piezoelectric nanogenerators in energy harvesting, sensors and biosensors, as well as in cell and tissue engineering, wound healing and drug delivery