Co-axial wet-spinning in 3D Bioprinting: state of the art and future perspective of microfluidic integration

Nowadays, 3D bioprinting technologies are rapidly emerging in the field of tissue engineering and regenerative medicine as effective tools enabling the fabrication of advanced tissue constructs that can recapitulate in vitro organ/tissue functions. Selecting the best strategy for bioink deposition is often challenging and time consuming process, as bioink properties-in the first instance, rheological and gelation-strongly influence the suitable paradigms for its deposition. In this short review, we critically discuss one of the available approaches used for bioprinting-namely co-axial wet-spinning extrusion. Such a deposition system, in fact, demonstrated to be promising in terms of printing resolution, shape fidelity and versatility when compared to other methods. An overview of the performances of co-axial technology in the deposition of cellularized hydrogel fibres is discussed, highlighting its main features. Furthermore, we show how this approach allows (i) to decouple the printing accuracy from bioink rheological behaviour-thus notably simplifying the development of new bioinks- A nd (ii) to build heterogeneous multi-materials and/or multicellular constructs that can better mimic the native tissues when combined with microfluidic systems. Finally, the ongoing challenges and the future perspectives for the ultimate fabrication of functional constructs for advanced research studies are highlighted. © 2018 IOP Publishing Ltd

On-glass optoelectronic platform for on-chip detection of DNA

Lab-on-chip are analytical systems which, compared to traditional methods, offer significant reduction of sample, reagent, energy consumption and waste production. Within this framework, we report on the development and testing of an optoelectronic platform suitable for the on-chip detection of fluorescent molecules. The platform combines on a single glass substrate hydrogenated amorphous silicon photosensors and a long pass interferential filter. The design of the optoelectronic components has been carried out taking into account the spectral properties of the selected fluorescent molecule. We have chosen the [Ru(phen)2(dppz)]2+ which exhibits a high fluorescence when it is complexed with nucleic acids in double helix. The on-glass optoelectronic platform, coupled with a microfluidic network, has been tested in detection of double-stranded DNA (dsDNA) reaching a detection limit as low as 10 ng/μL

Lower genetic diversity in the limpet Patella caerulea on urban coastal structures compared to natural rocky habitats

Human-made structures are increasingly found in marine coastal habitats. The aim of the present study was to explore whether urban coastal structures can affect the genetic variation of hard-bottom species. We conducted a population genetic analysis on the limpet Patella caerulea sampled in both natural and artificial habitats along the Adriatic coast. Five microsatellite loci were used to test for differences in genetic diversity and structure among samples. Three microsatellite loci showed strong Hardy-Weinberg disequilibrium likely linked with the presence of null alleles. Genetic diversity was significantly higher in natural habitat than in artificial habitat. A weak but significant differentiation over all limpet samples was observed, but not related to the type of habitat. While the exact causes of the differences in genetic diversity deserve further investigation, these results clearly point that the expansion of urban structures can lead to genetic diversity loss at regional scales

Training Program at Medical School of Chieti, Italy

We describe the changes in medical training program offered at the G. D’Annunzio University Medical School in Chieti-Pescara, Italy, which took place over the last decade. The new curriculum differs from the previous one in several important aspects, including limited number of students admitted to school depending on the estimated needs for physicians, obligatory class attendance, student attendance in preclinical laboratories, formative credits as a measure of student activity, and elective subjects. Furthermore, all medical graduates are allowed to take the State exam to obtain the license to practice, which was not the case previously. As a result of these major changes, a higher number of students graduates in due time. The changes made in the medical education curriculum in Italy have enabled Italian medical graduates to work in European Community Hospitals, because their medical degree is recognized in other EU countries. The main motif that drives the Medical School in Chieti-Pescara is the achievement of high quality in medical education and biomedical research by creating as strong a relationship between education and research as possible

Fish stock study on the Ridge of Santa Croce

Il presente studio è stato finalizzato alla caratterizzazione del Dosso di Santa Croce (Golfo di Trieste – Alto Adriatico) in termini di morfobatimetria e di distribuzione dei banchi di pesce presenti in questa zona. A tal fine è stato utilizzato un “echosounder” che permette, tramite riflessione degli impulsi acustici inviati, di individuare banchi di pecse o plankon, valutandone la relativa taglia, stimare abbondanza e densità dei medesimi organismi, studiarne il comportamento e le dinamiche migratorie e mappare il fondale. Lo strumento ha permesso, nel presente lavoro, di valutare in maniera semplice la densità e l’abbondanza relative dei banchi di pesce, ma la conversione in valori assoluti è stata resa difficoltosa dall’impossibilità di prelevare specie nell’area, sottoposta a protezione. Pertanto uno strumento utile da utilizzare in abbinamento all’echosounder sembrerebbe poter essere il “visual census” (campionamento visivo) per valutare le specie presenti nei banchi

Identifying conformational changes with site-directed spin labeling reveals that the GTPase domain of HydF is a molecular switch

[FeFe]-hydrogenases catalyse the reduction of protons to hydrogen at a complex 2Fe[4Fe4S] center called H-cluster. The assembly of this active site is a multistep process involving three proteins, HydE, HydF and HydG. According to the current models, HydF has the key double role of scaffold, upon which the final H-cluster precursor is assembled, and carrier to transfer it to the target hydrogenase. The X-ray structure of HydF indicates that the protein is a homodimer with both monomers carrying two functional domains: a C-terminal FeS cluster-binding domain, where the precursor is assembled, and a N-terminal GTPase domain, whose exact contribution to cluster biogenesis and hydrogenase activation is still elusive. We previously obtained several hints suggesting that the binding of GTP to HydF could be involved in the interactions of this scaffold protein with the other maturases and with the hydrogenase itself. In this work, by means of site directed spin labeling coupled to EPR/PELDOR spectroscopy, we explored the conformational changes induced in a recombinant HydF protein by GTP binding, and provide the first clue that the HydF GTPase domain could be involved in the H-cluster assembly working as a molecular switch similarly to other known small GTPases

An all-glass microfluidic network with integrated amorphous silicon photosensors for on-chip monitoring of enzymatic biochemical assay

A lab-on-chip system, integrating an all-glass microfluidics and on-chip optical detection, was developed and tested. The microfluidic network is etched in a glass substrate, which is then sealed with a glass cover by direct bonding. Thin film amorphous silicon photosensors have been fabricated on the sealed microfluidic substrate preventing the contamination of the micro-channels. The microfluidic network is then made accessible by opening inlets and outlets just prior to the use, ensuring the sterility of the device. The entire fabrication process relies on conventional photolithographic microfabrication techniques and is suitable for low-cost mass production of the device. The lab-on-chip system has been tested by implementing a chemiluminescent biochemical reaction. The inner channel walls of the microfluidic network are chemically functionalized with a layer of polymer brushes and horseradish peroxidase is immobilized into the coated channel. The results demonstrate the successful on-chip detection of hydrogen peroxide down to 18 mu M by using luminol and 4-iodophenol as enhancer agent

Engineering muscle networks in 3D gelatin methacryloyl hydrogels: influence of mechanical stiffness and geometrical confinement

In this work, the influence of mechanical stiffness and geometrical confinement on the 3D culture of myoblast-laden gelatin methacryloyl (GelMA) photo-crosslinkable hydrogels was evaluated in terms of in vitro myogenesis. We formulated a set of cell-laden GelMA hydrogels with a compressive modulus in the range 1÷17 kPa, obtained by varying GelMA concentration and degree of cross-linking. C2C12 myoblasts were chosen as the cell model, to investigate the supportiveness of different GelMA hydrogels on myotube formation up to 2 weeks. Results showed that the hydrogels with a stiffness in the range 1÷3 kPa provided enhanced support to C2C12 differentiation in terms of myotube number, rate of formation and space distribution. Finally, we studied the influence of geometrical confinement on myotube orientation by confining cells within thin hydrogel slabs having different cross-sections: i) 2000×2000 m, ii) 1000×1000 m and iii) 500×500 m. The obtained results showed that by reducing the cross-section—i.e., by increasing the level of confinement—myotubes were more likely restrained and formed aligned myostructures that better mimicked the native morphology of skeletal muscle

Integration of amorphous silicon balanced photodiodes and thin film heaters for biosensing application

This work presents the development and testing of an integrated system for on-chip detection of thermochemiluminescent biomolecules. The activation energy of the reaction is provided by a transparent structure of thin film heaters deposited on one side of a glass substrate. Light, passing through the substrate, reaches an array of amorphous silicon differential structure deposited on the opposite side of the glass substrate. The structure is designed to perform differential current measurements between a light- shielded diode, whose current is sensitive only to temperature, and a photosensor, sensitive to both incident light and temperature. The device therefore balances the thermal variations of the photodiode current and reduces the dark-current noise. These features make the presented system very appealing as highly miniaturized micro-analytical devices for biosensing applications