Three-layered porous device in PCL/PEG blend for interface tissue engineering

Tissue interfaces, such as cartilage-to-bone, exhibit anisotropic structural properties, which gradually vary from one tissue to another. Consequently a regenerative scaffold designed for interface tissues should exhibit a gradient in composition, structure and mechanical features, mimicking those of the native zones. In particular, the architecture of pores plays a central role. Indeed, a biomedical implant should be designed with porosityand pore size gradients simulating the structure of the two interface tissues. One of the most common techniques to prepare porous scaffolds is the particulate leaching method, which involves the selective leaching of a mineral or organic compound as poro…

PCL/PEG based membranes for bacterial cells immobilization stimulate actinorhodin antibiotic production in S. coelicolor

The actinomycetes, Gram-positive filamentous bacteria, are the most prolific source of natural antibiotics. At industrial level, antibiotics from actinomycetes are usually produced at low levels by mean of fermentative processes in submerged cultivations, where one of the major factors negatively affecting bioproductivity is the phenomenon of a pellet-shaped biomass growth. The strategies based on cell-immobilization, which were already proven improving bacterial bioprocess productivity, could stimulate antibiotic production in actinomycetes.

Enhancement of antibiotic productions by plasma modified PLA electrospun membranes in Streptomyces coelicolor immobilized-cell cultivations

This study, encouraging the use of PLA membranes for actinomycetes cultivations, could unveil functional insights associated with antibiotic production and S. coelicolor cellimmobilization

Improvement of actinorhodin production yield in Streptomyces coelicolor by immobilized-cell cultivations by using PCL- and PLA-based films

Actinomycetes are Gram-positive bacteria producing most of naturally occurring antibiotics (Donadio et al., 2010). At industrial level, antibiotics are produced by submerged fermentations where the actinomycete filamentous morphology negatively affects bioproductivity (van Dissel et al., 2014). Microporous membranes for bacterial cell-immobilization were already proven increasing bioproductivity in Streptomyces coelicolor, that is a model actinomycete producing the blue pigmented actinorhodin (ACT) antibiotic (Scaffaro et al., 2016). To develop an immobilized-cell bioreactor system, different kinds of polycaprolactone (PCL) and polylactic acid (PLA) films were produced by an electrospinning…

Effect of Streptomyces coelicolor M145 cell immobilization on actinorhodin production

Non previsto

Structure and composition of intertidal biofilms which enhance the settlement of the central-Mediterranean reef builder Dendropoma cristatum (Biondi 1859).

Introduction Marine biofilms are complex matrix of microorganisms and mucopolysaccharide substances which develop on all submerged surfaces, providing a variety of physical-bio-chemical cues which affect the settlement of a wide range of benthic organisms. Biofilm community composition, 3-D structure and metabolic activity vary over time. Few studies report the biological and physical changes in marine biofilm development in relationship to their effects on benthic colonisation. Biofilm maturity has been reported to enhance the settlement rate of the central-Mediterranean Dendropoma cristatum (Biondi, 1859), an intertidal vermetid gastropod which builds up ecologically relevant reefs, subje…

PREPARATION AND CHARACTERIZATION OF BIOPOLYMERIC POROUS STRUCTURES FOR ADVANCED APPLICATIONS

Porous biopolymers received an increasing academic and industrial interest finding application in several fields such as tissue engineering, bioprocess intensification and waste removal. Tissue engineering combines the knowledge of materials science and bioengineering in order to develop structures able to substitute and restore the normal function of injured or diseased tissues. In this context, polymeric 3D or 2D scaffolds are widely investigated as temporary cell guidance during the tissue restore. Porous biomaterials can offer a versatile and cost effective way for immobilization of filamentous microorganisms in submerged fermentation processes for the production of biologically active …

IMPROVED PRODUCTION OF THE ANTIBIOTIC ACTINORHODIN IN STREPTOMYCES COELICOLOR IMMOBILIZED-MYCELIAL CELL CULTIVATIONS

Objectives i) Evaluation of ACT production in Streptomyces coelicolor M145 mycelial cells immobilized on polycaprolactone (PCL) and polylactic acid (PLA) nanofiber membranes, modified or not by an O2- plasma treatment. ii) Identification of gene products associated with the improvement of ACT production.

Fabrication of Chitosan-Silver Nanoparticles composite coatings by galvanic deposition for orthopaedic implants

Biopolymeric porous structure for selective oil sorption and activity intensification of oil-degrading bacteria

Oil pollution is one of the environmental concerns that are currently becoming a major issue in the petroleum industry. Among the different methods for environmental cleaning, the use of sorbents to recover the spilled oils is becoming more and more attractive because of their peculiar advantages such as reusability and recoverability of the oil. In this context, bioremediation is often considered a promising and cost-effective technology that could help a more sustainable recovery of contaminated water by using oil-degrading microorganisms. In this work, it is proposed a PCL-based biodegradable and floatable oil removal sponge, able to immobilize and increase biodegradation ability of hydr…

PLA/PCL nanofibrous blends via multi-jet electrospinning: processing-morphology-property relationships

Electrospinning permits to prepare ultrafine fibers with micro to nano-meter range diameters. Multi-jet approaches can be used to fabricate blend nanofibrous mats composed by two or more polymers presenting different properties such as degradation rate, mechanical properties and so on. In this study, a series of PLA/PCL blend nanofiber mats were prepared by dual-jet electrospinning. The relative weight ratio of PLA and PCL in blend was controlled by changing the flow ratio of the two syringe pumps containing the polymer solutions.

Composite Coatings of Chitosan and Silver Nanoparticles Obtained by Galvanic Deposition for Orthopedic Implants

In this work, composite coatings of chitosan and silver nanoparticles were presented as an antibacterial coating for orthopedic implants. Coatings were deposited on AISI 304L using the galvanic deposition method. In galvanic deposition, the difference of the electrochemical redox potential between two metals (the substrate and a sacrificial anode) has the pivotal role in the process. In the coupling of these two metals a spontaneous redox reaction occurs and thus no external power supply is necessary. Using this process, a uniform deposition on the exposed area and a good adherence of the composite coating on the metallic substrate were achieved. Physical-chemical characterizations were car…

Silica as a green exfoliant agent for graphene oxidepolymer nanocomposites prepared in the melt

For the first time, solid-state exfoliant agents were used to hinder the re-aggregation of graphene oxide (GO) during melt processing with polyamide 6 (PA6). This technique drastically reduces the time and difficulty related to solvent (removal, disposal, etc.), and avoids water consumption, since in this case 150 mL of water under mild operative conditions are enough to prepare the amount of GOS necessary for the realization of almost 100 grams of PA6- GOS nanocomposites with outstanding ultimate properties.