Rapid Prototyping of Polymeric Nanopillars by 3D Direct Laser Writing for Controlling Cell Behavior

Mammalian cells have been widely shown to respond to nano-and microtopography that mimics the extracellular matrix. Synthetic nano-and micron-sized structures are therefore of great interest in the field of tissue engineering, where polymers are particularly attractive due to excellent biocompatibility and versatile fabrication methods. Ordered arrays of polymeric pillars provide a controlled topographical environment to study and manipulate cells, but processing methods are typically either optimized for the nano-or microscale. Here, we demonstrate polymeric nanopillar (NP) fabrication using 3D direct laser writing (3D DLW), which offers a rapid prototyping across both size regimes. The NPs are interfaced with NIH3T3 cells and the effect of tuning geometrical parameters of the NP array is investigated. Cells are found to adhere on a wide range of geometries, but the interface depends on NP density and length. The Cell Interface with Nanostructure Arrays (CINA) model is successfully extended to predict the type of interface formed on different NP geometries, which is found to correlate with the efficiency of cell alignment along the NPs. The combination of the CINA model with the highly versatile 3D DLW fabrication thus holds the promise of improved design of polymeric NP arrays for controlling cell growth

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Structural modelling of optical and electrochemical properties of 4-aminodiphenylamines - optoelectronic studies on a polyaniline repeating unit

Amino-diphenylanilines and their planarized and twisted model compounds have been investigated by steady state and time-resolved absorption and emission, as well as by spectroelectrochemistry. These polyaniline model compounds show that the observation of excited states with full charge separation is linked to molecular twisting where the diaminobenzene is the donor and the phenyl group the acceptor. The observable charge transfer fluorescence shows the characteristic features of twisted intramolecular charge transfer (TICT) excited states, i.e. forbidden emissive properties and strong solvatochromic red shift. The transient absorption spectrum of the TICT state matches the ground state absorption spectrum of the electrochemically produced radical cation of the molecule. This is the first example where excited-state properties of the neutral and ground state properties of the radical cation are directly linked

Long-term outcomes of I-Stop TOMS™ male sling implantation for post-prostatectomy incontinence management

International audienceOBJECTIVES:To report long-term outcomes after I-Stop TOMS™ implantation for PPI.PATIENTS AND METHODS:A retrospective evaluation was conducted in three tertiary reference centers. All consecutive patients implanted with an I-Stop TOMS™ sling between 2007 and 2012 for mild to moderate PPI (24-hour Pad test<400g) without history of pelvic radiation therapy were included. Evaluation had been conducted preoperatively, at one and six months postoperative and yearly thereafter. The main outcome criterion was the number of pads per day. Secondary criteria were International Consultation on Incontinence Questionnaire (ICIQ), SF-36 questionnaire, and complications.RESULTS:A hundred patients were evaluated with a median follow-up of 58months [19-78]. Pad use was significantly reduced and quality of life improved at last follow-up (P<0.0001). The percentage of patients dry and socially continent (0 or 1 pad) were 40% and 77% at 1 year, then dropped to 15% and 22%, respectively after 5years. Twelve patients were treated by artificial urinary sphincter implantation, five by ProACT™ balloons and one by a re-do I-Stop TOMS™. No severe complications were recorded at last follow-up.CONCLUSIONS:I-Stop TOMS™ implantation is a safe and effective option in the short-term for mild to moderate PPI management. However, a significant trend to recurrence of leakage has been established after long-term follow-up. If confirmed by further studies, these results may substantially impact patient information before male sling implantation

Methacrylated Quinizarin Derivatives for Visible-Light Mediated Photopolymerization: Promising Applications in 3D-Printing Biosourced Materials under LED@405 nm

The high initiating properties of mono- (Q-1Ac) and dimethacrylated (Q-2Ac) quinizarin derivatives under visible-light irradiation are reported here. Associated with various co-initiators, such as iodonium salt (electron acceptor), an amine derivative (electron donor), or thiol cross-linker (H-donor), the quinizarin-derived photosensitizers lead to high conversions by radical photopolymerization in laminate or under air. Mechanisms of photoinitiation were deeply investigated by fluorescence, laser flash photolysis (LFP) and electron paramagnetic resonance (EPR) experiments. The use of soybean oil acrylate (SOA) as biobased monomer leads to highly cross-linked materials under visible-light, with comparable mechanical properties than UV-induced ones previously described in literature. Copolymerization of the photosensitizer (PS) with the polymer matrix not only prevents leakage, but also ensures antiadhesion properties of SOA materials against Staphylococcus aureus (S. aureus) under visible-light activation. Finally, complex 3D biobased structures are successfully obtained by 3D-printing under visible-light irradiation (LED@405 nm), opening opportunities to design photoinduced biosourced materials

Purpurin derivatives as visible-light photosensitizers for 3D printing and valuable biological applications

We report the synthesis of new visible-light photosensitizers derived from purpurin (mono-allyl-and triallyl-purpurin), and their use as type II photoinitiating systems when associated with N-methyldiethanolamine, bis(4-methylphenyl) iodonium hexafluorophosphate or tri-functionalized thiol (trimethylolpropane tris(3-mercaptopropionate)) for cationic and free-radical photopolymerization, and the initiation of thiol-ene reactions. These photoinitiating systems showed good initiating properties in laminate or under air upon visible-light exposure, i.e. LED@405 nm, 455 nm, 470 nm, 530 nm, and a Xe lamp. Steady-state photolysis, electron paramagnetic resonance, fluorescence analysis and laser flash photolysis have clearly highlighted the photochemical properties of the different photoinitiating systems and proved that purpurin derivatives could act as electron donors or as proton/proton-coupled electron transfer promoters when associated with appropriate additives. For the first time, we also demonstrated the capability of triallyl purpurin to produce newly designed 3D objects by 3D photoprinting technology. Interestingly, the photosensitizers from new 3D materials incorporating triallyl-purpurin have undoubtedly shown tremendous antibacterial properties with more than 99% of inhibition of bacterial adhesion upon visible-light exposure, even after many antibacterial cycling experiments, thus showing their capability to be recycled. This journal i

Purpurin derivatives as visible-light photosensitizers for 3D printing and valuable biological applications

We report the synthesis of new visible-light photosensitizers derived from purpurin (mono-allyl-and triallyl-purpurin), and their use as type II photoinitiating systems when associated with N-methyldiethanolamine, bis(4-methylphenyl) iodonium hexafluorophosphate or tri-functionalized thiol (trimethylolpropane tris(3-mercaptopropionate)) for cationic and free-radical photopolymerization, and the initiation of thiol-ene reactions. These photoinitiating systems showed good initiating properties in laminate or under air upon visible-light exposure, i.e. LED@405 nm, 455 nm, 470 nm, 530 nm, and a Xe lamp. Steady-state photolysis, electron paramagnetic resonance, fluorescence analysis and laser flash photolysis have clearly highlighted the photochemical properties of the different photoinitiating systems and proved that purpurin derivatives could act as electron donors or as proton/proton-coupled electron transfer promoters when associated with appropriate additives. For the first time, we also demonstrated the capability of triallyl purpurin to produce newly designed 3D objects by 3D photoprinting technology. Interestingly, the photosensitizers from new 3D materials incorporating triallyl-purpurin have undoubtedly shown tremendous antibacterial properties with more than 99% of inhibition of bacterial adhesion upon visible-light exposure, even after many antibacterial cycling experiments, thus showing their capability to be recycled. This journal i

Eosin-mediated synthesis of polymer coatings combining photodynamic inactivation and antimicrobial properties

International audiencePolymer coatings exhibiting photodynamic bacterial inactivation properties have been successfully engineered. Such coatings were obtained by photoinduced crosslinking of a PEG-diacrylate monomer associated with the eosin Y dye which was used as both a radical photoinitiator and an antibacterial agent. A dual curing process was followed by combining compatible and solvent-free polymerization mechanisms, i.e. Aza-Michael reaction and free-radical polymerization in the presence of amines. The kinetics evolution of the photopolymerization process was followed using in situ Fourier transform infrared spectroscopy, allowing for the elucidation of the underlying mechanistic pathways. The influence of eosin Y and amines on the thermal and mechanical properties of the films was evidenced and discussed in terms of crosslinking chemistry. The antibacterial properties of the coatings against two different strains (Escherichia coli and Staphylococcus aureus) were evaluated on short and long terms, revealing that eosin confers both photodynamic inactivation and antimicrobial properties to the films. These coatings are therefore particularly promising for disposable medical devices