Stage 2 - P3 2017
The project implementation schedule
Phase no. 23
Responsible: Dr. Carmen RISTOSCU
Title: "Funcționalizarea suprafeței implanturilor utilizand nanocompoziții cu proprietăți complementare: material bioactiv (biosticle) cu medicament (antibiotic)"
Phase no. 24
Responsible: Dr. Monica SCARISOREANU
Title: "Sinteza prin piroliza laser de nanoparticule carbonice si doparea sau acoperirea lor cu platina, utilizand tehnici chimice ude, ca materiale active pentru filtre catalitice"
Phase no. 25
Responsible: Dr. Catalin LUCULESCU
Title: "Laser spectroscopy applications for food industry"
Abstract: In this study, we followed various applications of Raman spectroscopy related to the food industry. Raman spectroscopy has proven to be a valuable noninvasive analytical tool both for the identification and for the quantitative estimation of the relevant compounds in the food industry. We analyzed representative additives (TiO2) in various forms of presentation, dairy products from various producers on the Romanian market (butter) and various fruits (citrus).
Phase no. 26
Responsible: Dr. Ruxandra BIRJEGA
Title: "Glucose oxidase immobilization on Ni,Al-layered double hydroxides films"
Abstract: The glucose oxidase (GOD) immobilization processes on layered double hydroxides (LDH) films were studied aiming the production of modified film/electrodes to be used in comparison with non-enzymatic Ni,Al-LDH electrodes. For this prospective research on the enzyme immobilization of LDH films the adsorption method was used. The effect of the co-intercalation of a surfactant (sodium dodecyl sulfate -SDS) on the ability of GOD to be immobilized was also studied. Three solutions were used:
i) GOD solution 10mg/mL
ii) SDS solution 0.25 mg/mL
iii) GOD (10 mg/mL) and SDS (0.25 mg/mL) (1:1)
GOD immobilization was attempted on Ni,Al LDH ( Ni/Al molar ratio of 3) films obtained via PLD at 532 and 1064 nm wavelengths. The characteristic and conditions for the deposition of these films were described in the previous report (2016). In order to understand the GOD immobilization process and the role played by the co-intercalated SDS the immobilization of GOD on Ni,Al-LDH films were compared with Mg,Al-LDH films and dodecyl sulfate modified Mg,Al-LDH films. Fourier transform IR spectroscopy and SEM analysis were used to characterize the films before and after immersion in the 3 solutions.
It has been concluded that GOD is more likely to be intercalated in Ni, Al-LDH films rather than in Mg,Al-LDH or DS modified Mg,Al-LDH films, due to the affinity of Mg,Al LDHs for carbonates. The DS functionalization of the films could eventually favored GOD immobilization for the films exhibiting a higher degree of delamination.
Phase no. 27
Responsible: Dr. Gabriel SOCOL
Title: "Testing the photocatalytic activity of functionalized structures for applications in water depollution"
Abstract: Three batches of TiO2 coatings obtained in different gaseous atmospheres (O2 - MO, N2- MN and Ar - MA) have been synthetized by pulsed laser deposition (PLD), using a KrF* excimer laser (λ= 248 nm și τFWHM = 10 ns) and applying a 40 Hz laser repetition rate. In order to achieve relevant data in respect with the morphology, topography and crystalline structure, the as-deposited coatings have been evaluated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-Ray Diffraction (XRD), respectively. SEM micrographs recorded in top-view, which are in accordance with AFM results, revealed morphological differences as a function of the ambient gas used during deposition. The microstructural characterization of the TiO2 samples highlighted the presence of a mixture of anatase and rutile with low crystallinity, with the indication that the main peak is at 25,36°, assigned to the anatase plan (101). Furthermore, the photocatalytic activity of the TiO2 coatings have been evaluated by degradation tests on rhodamine B solutions (pH = 7) which were irradiated under UV light by using a Hg lamp emitting at 254 nm, in the presence of the TiO2 coatings (MO, MN and MA). It should be mention that, unlike TiO2 coatings deposited at lower pressures and characterized by compact structure and low roughness, only those obtained under high pressure exhibited photocatalytic degradation activity of rhodamine B.
Phase no. 28
Responsible: Dr. Carmen TISEANU
Title: "Lanthanide-doped nanosystems for X ray imaging applications"
Abstract: This report contains our studies on biologically relevant luminescence of lanthanide doped nanoparticles aiming at applications in theranostics and temperature sensing. Near-infrared luminescence around 980 and 1500 nm was obtained under X-ray and optical excitation in several lanthanide doped oxide hosts, such as CeO2, Y2O3 and Lu2O3 and Gd2O2S. We have also obtained “quasi” persistent luminescence of Eu and Sm in SnO2 with emission lifetimes of the order of tens of ms. We present also first report on the luminescence thermometry properties of Er, Yb doped Gd2O2S microparticles under near infrared up-conversion excitation around 980 and 1500 nm measured in the 280 to 800 K interval. The thermometry properties are assessed using both cw and ns pulsed excitation as well as tuning the excitation wavelength across Yb and Er absorption profiles. Although for 1500 nm excitation, the temperature sensitivity is lower (~0.008 % K-1), our data represent a first step for opening the thermometry applications of this material at two biologically relevant near-infrared excitation ranges. All nanoparticles have been extensively optimized by using multiple strategies: co-doping with monovalent ions (Li), modifying the concentration of the dopant activator (Er: 0.3 ÷ 7%), use of a sensitizer co-dopant (20% Yb) and varying the anneal temperature. We have also shown that the emission enhancement by Li addition in Ln, Li−Y2O3 is due to improved crystallization and not to local structure distortion. Our results have been published in four ISI journals: (1) J. Phys. Chem. C. (2017) 121 (26), 14274–14284, (2) Sci. Rep. (2017) 7 (1) 9598, (3) Methods Appl. Fluoresc. (https://doi.org/10.1088/2050-6120/aa9ef9) and (4) and J. Alloys Compd. (2017) 711, 627-636.
Phase no. 29
Responsible: Dr. Emanuel AXENTE
Title: "Surface functionalization by biopolymer combinatorial coatings for nanomedicine"
Abstract: A new generation of implantable biomaterials should possess smart surfaces and interfaces, able to modulate cellular behaviour and moreover, directly address specific clinical issues. In this report we investigated and present recent advances in the field of laser-based combinatorial synthesis of thin biopolymer films with gradient of composition for biomedical applications. The main biopolymer classes will be briefly introduced and the importance of such thin films with respect to applications like tissue engineering and the fabrication of cell instructive environments will be presented. Combinatorial Matrix-Assisted Pulsed Laser Evaporation (C-MAPLE) method for the fabrication of gradient coatings is depicted followed by selected applications and recent results for nanomedicine.
Phase no. 30
Responsible: Dr. Cristina GHEORGHE
Title: "Composition and structure effects on lanthanide absorption and amissions properties in single crystal and policrystalline ceramics garnets"
Abstract: Spectroscopic investigation of Dy3+ doped Ca3(Nb,Ga)5O12 (CNGG) and Ca3(Li,Nb,Ga)5O12 (CLNGG) single crystals and ceramics were performed in order to assess their potential as a laser material for yellow emission for the first time. Dy:CNGG and Dy:CLNGG single crystals were grown by the Czochralski method and ceramics samples were obtained by solid state reaction. All samples were investigated by high-resolution spectroscopic measurements (static and dynamics). The Judd-Ofelt intensity parameters for the f-f transitions of Dy3+ in CNGG and CLNGG single crystals, were used to determine radiative transition rates Ar, branching ratios β, and radiative lifetime τr of the fluorescent Dy3+ levels. Based on low temperature absorption and emission spectra, partial energy level diagram of Dy3+ doped CNGG and CLNGG single crystals were obtained. The emission cross-section for the 4F9/2→6H13/2 transition of special interest for laser application was determined. The room temperature decay curves were analyzed through the framework of the Inokuti–Hirayama (I-H) model and the results shows that electric dipole-dipole interaction are responsible for the energy transfer processes between Dy3+ ions in CNGG and CLNGG single crystals.
Phase no. 31
Responsible: Dr. Lucian GHEORGHE
Title: "Advanced nonlinear optical crystals for laser emission generation at specific wavelengths in visible domain with applications in medicine and environmental protection"
Abstract: Almost congruent melting nonlinear optical (NLO) crystals of LaxGdyScz(BO3)4 (x + y + z = 4) - LGSB were grown by the Czochralski method, for the first time to our knowledge. Different heating assemblies were designed, and good optical quality NLO crystals of LGSB with a relatively large size of about 12 mm in diameter and 25-30 mm in length were obtained. The melt composition and growth parameters were optimized, and the best quality crystals were grown along the c-axis direction from the La0.678Gd0.572Sc2.75(BO3)4 starting melt composition at pulling and rotation rates of 2 mm/h and 8-10 rpm, respectively. The grown crystals are nonhygroscopic and X-ray analysis showed that they crystallize in the noncentrosymmetric space group R32 (Z = 3). The transmission window and refractive indices were measured and SHG phase-matching properties were reported. These favorable characteristics coupled with the opportunity to grow large dimension LGSB crystals by the Czochralski method make them very promising for NLO applications, especially for frequency conversion of high-average power laser beams in the visible wavelength ranges.
Phase no. 32
Responsible: Dr. Cristina SURDU-BOB
Title: "The chemical stability evaluation in simulated body fluids of coatings deposited by TVA onto polymeric substrates. Morphological, compositional, structural and adherence studies of coatings after corrosion evaluation"
Abstract: At this second stage of the project we continued the investigations started earlier concerning the synthesis of quality DLC films on commercially available suture wires. Samples made of four types of suture wires were employed in the study. Optimal deposition conditions for obtaining continuous and crack-free films on suture wires wholly made of polyester or polyester pre-coated silk. For this the following analytical techniques were used: optical microscopy, composition analysis (using XPS) and thickness measurements using XRR. In order to assess the quality of deposited layers, the suture wires were subjected to mechanical stress (by rolling on cylinders of different diameters) and also to accelerated chemical corrosion (by electrochemistry, using simulated biological fluids).
Using a specially designed automated system, deposition of DLC films on commercial, long, suture wires of 2.5 m standard length was also undertaken. It was demonstrated that the high voltage anodic plasma (HVAP) developed in our laboratory can be successfully used for the deposition of adherent, compact and chemically inert DLC films that withstand winding mechanical stress.
The project lays down foundations of a low temperature technology for the deposition of wire shaped substrates. Further assessment of deposited suture wires using standard procedures will allow industrial application of this technology.
Phase no. 33
Responsible: Dr. Andreea MATEI
Title: "Laser photopolymerization for biomedical applications: substrate processing for liquid flow optimization"
Abstract: Microfluidic systems follow current trend of miniaturization of biosensors. In this work, we produced polymeric structures with controlled geometry by direct laser writing technique. Irradiating a commercial photoresist with a ps laser (λ = 355 nm) we produced structures consisting of a reservoir and a channel with various dimensions. The laser power varied in the range 2-75 mW and the scanning speed was fixed, 0.5 mm/s.
For a second set of experiments, a beam of a Ti-sapphire femtosecond-laser incorporated in a two-photon polymerization setup was used to produce similar channels in a home-made photoresist. The micro-structures were written on a glass substrate at a speed of 50 µm/s, with a laser excitation power of 12, 18 and 24 mW.
The as processed structures have been further exposed to atmospheric pressure plasma treatment at room temperature in order to optimize the liquid flow process. Additional experiments have been carried out on the use of these structures as a master for obtaining micronic channels in shellac.