Search

Thin films of electrochromic (EC) materials are being used as energy saving platforms. However, manufacturing high quality of such films while ensuring their superior stability and high coloration availability, as well as their persistency in diverse conditions of temperature and/or illumination, is challenging. Herein we proposed to create the next generation of composites that display EC characteristics using a user-controlled manufacturing strategy based on Matrix Assisted Pulsed Laser Evaporation (MAPLE). In our approach, tungsten trioxide and graphene oxide were employed as starting materials, with MAPLE controlling material deposition conditions and overall composites’ thickness. The resulting EC composites were characterized for their chemical and physical properties using Fourier Transform Infrared Spectroscopy and Energy Dispersive Spectroscopy, and Optical and Atomic Force Microscopy respectively, with changes in their electrochemical characteristics being evaluated by cyclic voltammetry and related to film thickness through the use of spectrophotometry. It was found that MAPLE deposition conditions allow for formation of composites that display enhanced electron transport capabilities and high energy efficiency at their interfaces; further, it was found that MAPLE allowed for uniform films production, of controlled thickness as well as eliminated possible impurities normally associated with other methods used for EC films production such as sputtering, sol–gel or electrodeposition, and chemical wet deposition respectively. Our work could potentially provide a user-controlled synthesis and manufacturing strategy for the formation of next generation of EC thin films that have minimum interfacial defects while possessing maximum conversion efficiency to thus influence and/or dictate their energy saving profiles.

In this paper, we present for the first time the obtaining and characterization of new antibacterial and biocompatible nano-ZnO–bacterial cellulose (BC) material with controlled interfaces for studying in vitro microorganisms (Escherichia Coli (ATCC 8737), B. subtilis Spizizenii Nakamura (ATCC 6633), Candida albicans (ATCC10231)) and mammalian cells (human dermal fibroblast cells) response. The use of BC based material with controlled characteristics in terms of quantity and distribution of ZnO onto BC membrane (with 2D and 3D fibers arrangement) is directly correlated with the surface chemical and topographical properties, the method of preparation, and also with the type of cells implied for the specific application within the bioengineering fields. In our study, the uniform distribution and the control on the quantity of ZnO nanoparticles onto 3D BC were obtained using matrix assisted pulsed laser evaporation (MAPLE) method. The influence on particle distribution onto 3D bio cellulose were investigated based on two types of solvents (water and chloroform) involved in target preparation within MAPLE deposition. The attachment of the nanoparticles to the bacterial cellulose surface and fibrils was demonstrated by SEM and FT-IR studies. The BC-ZnO showed both resistance to bacteria-sticking and non-cytotoxic effect on the human dermal fibroblasts cells at a mass distribution onto surface of 1.68 µg ZnO NPS/mm2. These results represent a good premise in terms of tailoring BC substrates with ZnO particles that could determine or enhance both the biocompatibility and antibacterial properties of BC-composite materials. Keywords: Bacterial cellulose, Zinc oxide nanoparticles, MAPLE deposition technique, Antibacterial effect, Biocompatibility

This minireview appraises the chemical sensors and biosensors with the bio/sensitive active films obtained by matrix assisted laser evaporation (MAPLE). An overall presentation and examples of the materials utilized thus far introduce the discussion of sensing applications, where the following categories of biosensors are critically appraised: optical sensors (surface plasmon resonance, fluorescence microscopy, long period grating fiber); surface acoustic wave sensors; and electrochemical sensors. The deposition of active layers of biomolecules, potentially useful as sensing interfaces, is discussed in relation to the experimental parameters of MAPLE deposition, with emphasis on the preservation of structure and activity of biomolecules. Additionally, chemoselective layers, temperature responsive and antifouling coatings are also reviewed, as these be can be combined with the active layers to obtain advanced sensing interfaces, showing the versatility of MAPLE. The review concludes with future developments and perspectives.

In the last decades, optimizing implant properties in terms of materials and biointerface characteristics represents one of the main quests in biomedical research. Modifying and engineering polyvinylidene fluoride (PVDF) as scaffolds becomes more and more attractive to multiples areas of bio-applications (e.g., bone or cochlear implants). Nevertheless, the acceptance of an implant is affected by its inflammatory potency caused by surface-induced modification. Therefore, in this work, three types of nano-micro squared wells like PVDF structures (i.e., reversed pyramidal shape with depths from 0.8 to 2.5 microns) were obtained by replication, and the influence of their characteristics on the inflammatory response of human macrophages was investigated in vitro. FTIR and X-ray photoelectron spectroscopy analysis confirmed the maintaining chemical structures of the replicated surfaces, while the topographical surface characteristics were evaluated by AFM and SEM analysis. Contact angle and surface energy analysis indicated a modification from superhydrophobicity of casted materials to moderate hydrophobicity based on the structure’s depth change. The effects induced by PVDF casted and micron-sized reversed pyramidal replicas on macrophages behavior were evaluated in normal and inflammatory conditions (lipopolysaccharide treatment) using colorimetric, microscopy, and ELISA methods. Our results demonstrate that the depth of the microstructured surface affects the activity of macrophages and that the modification of topography could influence both the hydrophobicity of the surface and the inflammatory response.

In this paper, we present an e-nose for the detection of volatile compounds based on an array of six surface acoustic wave (SAW) resonators coated with five different polymers (i.e. polyepichlorohydrin, polyisobutylene, polyethylenimine, (hydroxypropyl)methyl cellulose, and poly(styrene-co-maleic acid) partial isobutyl/methyl mixed ester, plus an uncoated SAW device used as reference. In particular, matrix assisted pulsed laser evaporation was used to deposit thin polymer layers which were subsequently used as donor films in the laser induced forward transfer process to selectively cover each SAW resonators of the array. The SAW e-nose was tested upon exposure to vapors of ethyl acetate, dimethyl methylphosphonate, dichloromethane, dichloropentane, and water. The frequency responses showed, for each of the sensors, a different sensitivity to the selected chemical agents and a good agreement with the theoretical sensitivities derived from the linear-solvation-energy-relationship between vapors and polymers. Specifically, the implemented SAW e-nose allowed the discrimination between all the considered vapors in the tested concentrations ranges as highlighted by the results of principal component analysis. Finally, the obtained results indicated that laser deposition of polymers onto SAW resonators is possible without significant modifications of their functionality and with a good reliability and reproducibility.

A hybrid was synthesized using tungsten trioxide and graphene as starting materials. The hybrid's characteristics were investigated by scanning and transmission microscopy, and Raman and adsorption spectroscopy respectively. Incubation with a model chemical compound used for evaluating oxidative degradation showed enzymatic-like activity. A future application for decontamination-based platforms is envisioned.

Properties such as large surface area, high pore volume, high chemical and thermal stability, and structural flexibility render zeolitic imidazolate frameworks (ZIFs) well-suited materials for gas separation, chemical sensors, and optical and electrical devices. For such applications, film processing is a prerequisite. Herein, matrix-assisted pulsed laser evaporation (MAPLE) was successfully used as a single-step deposition process to fabricate ZIF-8 films. By correlating laser fluency and controlling the specific transfer of lab-synthesized ZIF-8, films with user-controlled physical and chemical properties were obtained. Films’ characteristics were evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The analysis showed that frameworks of ZIF-8 can be deposited successfully and controllably to yield polycrystalline films. The deposited films maintained the integrity of the individual ZIF-8 framework, while undergoing minor crystalline and surface chemistry changes. No significant changes in particle size were observed. Our study demonstrated control over both the MAPLE deposition conditions and the outcome, as well as the suitability of the listed deposition method to create composite architectures that could potentially be used in applications ranging from selective membranes to gas sensors.

Osseous implantology&rsquo, s material requirements include a lack of potential for inducing allergic disorders and providing both functional and esthetic features for the patient&rsquo, s benefit. Despite being bioinert, Zirconia ceramics have become a candidate of interest to be used as an alternative to titanium dental and cochlear bone-anchored hearing aid (BAHA) implants, implying the need for endowing the surface with biologically instructive properties by changing basic parameters such as surface texture. Within this context, we propose anisotropic and isotropic patterns (linear microgroove arrays, and superimposed crossline microgroove arrays, respectively) textured in zirconia substrates, as bioinstructive interfaces to guide the cytoskeletal organization of human mesenchymal stem cells (hMSCs). The designed textured micro-nano interfaces with either steep ridges and microgratings or curved edges, and nanoroughened walls obtained by direct femtosecond laser texturing are used to evaluate the hMSC response parameters and osteogenic differentiation to each topography. Our results show parallel micro line anisotropic surfaces are able to guide cell growth only for the steep surfaces, while the curved ones reduce the initial response and show the lowest osteogenic response. An improved osteogenic phenotype of hMSCs is obtained when grown onto isotropic grid/pillar-like patterns, showing an improved cell coverage and Ca/P ratio, with direct implications for BAHA prosthetic development, or other future applications in regenerating bone defects.

International audience; Carbon nanofibers (CNF) are efficient electrode modifiers in electrochemical biosensors that enhance the electrochemical active area, induce electrocatalytic effect toward the oxidation of the enzymatic cofactor nicotinamide adenine dinucleotide (reduced form, NADH), and enable the quantitative immobilization of enzymes. Combining CNF with efficient and stable mediators radically augments the speed of electron transfer between NADH and solid electrodes and leads to electrochemical sensors characterized by high sensitivity and stability. The main aim of this work was to investigate the performance of a novel mediator for NADH with advantageously low solubility in an electrochemical detector based on a screen-printed CNF electrode as well as its potential in biosensing. Using a mediator, prepared from Meldola Blue and Ni hexamine chloride, a stable and sensitive electrochemical NADH sensor is provided with a detection limit of 0.5 μmol L−1. Further on, covalent immobilization of a recently described aldehyde dehydrogenase from the Antarctic Flavobacterium PL002 strain on the surface of the mediator-modified electrode produced a stable biosensor for the detection of aldehydes. When integrated in a flow injection analysis (FIA) setup with amperometric detection at 0.1 V vs. Ag/AgCl, the measurement of benzaldehyde with a detection limit of 10 μmol L−1 over a linear range of 30–300 μmol L−1 is possible. Determination of trace benzaldehyde impurities in a pharmaceutical excipient was also demonstrated and results compared with a chromatographic method.

Recent advancements in biomedicine have focused on designing novel and stable interfaces that can drive a specific cellular response toward the requirements of medical devices or implants. Among these, in recent years, electroactive polymers (i.e., polyvinylidene fluoride or PVDF) have caught the attention within the biomedical applications sector, due to their insolubility, stability in biological media, in vitro and in vivo non-toxicity, or even piezoelectric properties. However, the main disadvantage of PVDF-based bio-interfaces is related to the absence of the functional groups on the fluoropolymer and their hydrophobic character leading to a deficiency of cell adhesion and proliferation. This work was aimed at obtaining hydrophilic functional PVDF polymer coatings by using, for the first time, the one-step, matrix-assisted pulsed evaporation (MAPLE) method, testing the need of a post-deposition thermal treatment and analyzing their preliminary capacity to support MC3T3-E1 pre-osteoblast cell survival. As osteoblast cells are known to prefer rough surfaces, MAPLE deposition parameters were studied for obtaining coatings with roughness of tens to hundreds of nm, while maintaining the chemical properties similar to those of the pristine material. The in vitro studies indicated that all surfaces supported the survival of viable osteoblasts with active metabolisms, similar to the &ldquo, control&rdquo, sample, with no major differences regarding the thermally treated materials, this eliminates the need to use a secondary step for obtaining hydrophilic PVDF coatings. The physical-chemical characteristics of the thin films, along with the in vitro analyses, suggest that MAPLE is an adequate technique for fabricating PVDF thin films for further bio-applications.

The use of smart coatings with tunable characteristics in bioengineering fields is directly correlated with the surface chemical and topographical properties, the method of preparation, and also with the type of cells implied for the specific application. In this work, a versatile surface modification technique based on the use of lasers (Matrix-Assisted Pulsed Laser Evaporation (MAPLE)) was used to yield poly(N-isopropylacrylamide) (pNIPAM) and its derivatives (amine, azide and amide terminated pNIPAM) functional and termoresponsive thin films. Surface properties of pNIPAM and its derivative films such as morphology, roughness and hydrophobic/hydrophilic character, as well as the thermoresponsive capacity were investigated by atomic force microscopy and contact angle measurements. The chemical characteristics of the pNIPAM based thin films were analysed by Fourier Transform Infrared Spectroscopy (FTIR). The chemical functionality was kept for all the samples obtained by MAPLE and the thermoresponse was demonstrated by the change in the contact angle and thickness values when the temperature was shifted from 37 °C to 24 °C for all the materials tested, with a smaller change for maleimide terminated pNIPAM. Biological assays performed in vitro (fluorescence microscopy and Scanning Electron Microscopy (SEM)) confirmed the conditioning of the early mesenchymal stem cell (MSC) growth by specific chemistry of the coatings. The cell imaging analysis revealed no cytotoxic effect of pNIPAM surfaces irrespective of type of functionalization. An increased proliferation rate of the cells grown on pNIPAM-azide surfaces and a lower cell density on pNIPAM-maleimide surfaces compared to the pNIPAM surfaces was observed, which can direct their use to potential surfaces in regenerative medicine approaches.

In this study a “Gum Metal” titanium-based alloy, Ti-31.7Nb-6.21Zr-1.4Fe-0.16O, was synthesized by melting and characterized in order to evaluate its potential for biomedical applications. The results showed that the newly developed alloy presents a very high strength, high plasticity and a low Young's modulus relative to titanium alloys currently used in medicine. For further bone implant applications, the newly synthesized alloy was surface modified with graphene nanoplatelets (GNP), sericin (SS) and graphene nanoplatelets/sericine (GNP–SS) composite films via Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The characterization of each specimen was monitored by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) measurements, and Fourier Transform Infrared Spectroscopy (FTIR). The materials' surface analyses suggested the successful coating of GNP, SS and GNP–SS onto the alloy surface. Additionally, the activities of pre-osteoblasts such as cell adhesion, cytoskeleton organization, cell proliferation and differentiation potentials exhibited on these substrates were investigated. Results showed that the GNP–SS-coated substrate significantly enhanced the growth and osteogenic differentiation of MC3T3-E1 cells when compared to bare and GNP-coated alloy. Collectively, the results show that GNP–SS surface-modified Gum alloy can modulate the bioactivity of the pre-osteoblasts holding promise for improved biological response in vivo.

In this work, we propose a new design for biodegradable composite coatings obtained by laser methods, which are aimed at evaluating the effects of active antitumoral elements on osteosarcoma cells. Our approach relies on embedding curcumin, which is a natural polyphenol having antitumoral properties, within biodegradable copolymer coatings (i.e. polyvinyl alcohol-polyethylene glycol − PVA-PEG) by using matrix assisted pulsed laser evaporation (MAPLE). The structural and morphological characteristics of the coatings were tailored by using different solvents (water, ethanol, benzene, dimethylsufoxide) as deposition matrix. The morphological characteristics of the resulting films were investigated by atomic force microscopy (AFM), whereas their chemical composition was characterized by Fourier transform infrared spectroscopy (FTIR). These characteristics were correlated with the degradation behavior by using ellipsometry (SE) and AFM measurements data. The in vitro study of the MG-63 osteosarcoma cell behavior indicates that the developed hybrid coatings significantly decreased osteosarcoma cell viability and proliferation potential. The physico-chemical characteristics of the thin films, along with the preliminary in vitro analyses, suggest that our developed polymeric hybrid coatings represent an efficient way to tackle the design of antitumoral surfaces, with applications in biomedicine.

Design and functionalization strategies for bio-functional coatings based on biodegradable and biocompatible materials intended to be employed for targeting cells activity and enhancing the bio-response are essential for both research and clinical applications. Active compounds such as ceramics and/or proteins are used for enhancing cellular response. In the last years, recent studies showed that the distribution of ceramic nanoparticles such hydroxyapatite (HA) and Lactoferrin (LF) presence have significant influence for nano-composites interfaces for osteoblast response envisaging osseous implant application. Therefore, this work is focused on embedding HA spherical nanoparticles and lactoferrin (LF) within synthetic biodegradable copolymers Poly(ethylene glycol)- block -poly(e-caprolactone) methyl ether (PEG-block-PCL Me) for the preparation of new nanocomposites coatings targeting the modulated response of osteoblast cells (i.e adhesion, mineralization). The controlled incorporation of HA and LF within the synthetic copolymeric substrates was performed by matrix assisted pulsed laser evaporation (MAPLE) method using a modular target system. The resulting morphologies and the main features were studied by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Fourier Transform Infrared Spectroscopy (FTIR) data demonstrates that the functional groups in the MAPLE-deposited films remain intact for the individual compounds and that LF was not affected by the solvents used for copolymer. The bio-functionality of the coatings has been tested using the correlated characteristics of the coatings with MC3T3-E1 murine osteoblasts response in vitro . The results clearly revealed that the coatings with HA and LF incorporated in the polymeric matrix have enhanced stability as compared with single element coatings, and that the osteoblast behavior (cell adhesion/morphology, proliferation and matrix mineralization) was differentially influenced by the variations in the physicochemical characteristics of materials surface polymeric layers.

Lysozyme is an enzyme found in biological fluids, which is upregulated in leukemia, renal diseases as well as in a number of inflammatory gastrointestinal diseases. We present here the development of a novel lysozyme sensing concept based on the use of Micrococcus lysodeikticus whole cells adsorbed on graphene oxide (GO)-coated Surface Plasmon Resonance (SPR) interfaces. M. lysodeikticus is a typical enzymatic substrate for lysozyme. Unlike previously reported sensors which are based on the detection of lysozyme through bioaffinity interactions, the bioactivity of lysozyme will be used here for sensing purposes. Upon exposure to lysozyme containing serum, the integrity of the bacterial cell wall is affected and the cells detach from the GO based interfaces, causing a characteristic decrease in the SPR signal. This allows sensing the presence of clinically relevant concentrations of lysozyme in undiluted serum samples.

Laser-deposited gold immobilization layers with different porosities were incorporated into Love Wave Surface Acoustic Wave sensors (LW-SAWs). Acetylcholinesterase (AChE) enzyme was immobilized onto three gold interfaces with different morphologies, and the sensor response to chloroform was measured. The response of the sensors to various chloroform concentrations indicates that their sensing properties (sensitivity, limit of detection) are considerably improved when the gold layers are porous, in comparison to a conventional dense gold layer. The results obtained can be used to improve properties of SAW-based biosensors by controlling the nanostructure of the gold immobilization layer, in combination with other enzymes and proteins, since the design of the present sensor is the same as that for a Love Wave biosensor.

The improvement in the research area of the implant by surface functionalization when correlated with the biological response is of major interest in the biomedical field. Based on the fact that the inflammatory response is directly involved in the ultimate response of the implant within the body, it is essential to study the macrophage-material interactions. Within this context, we have investigated the composite material-macrophage cell interactions and the inflammatory response to these composites with amorphous hydroxyapatite (HA), Lactoferrin (Lf), and polyethylene glycol-polycaprolactone (PEG-PCL) copolymer. All materials are obtained by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique and characterized by Atomic Force Microscopy and Scanning Electron Microscopy. Macrophage-differentiated THP-1 cells proliferation and metabolic activity were assessed by qualitative and quantitative methods. The secretion of tumor necrosis factor alpha (TNF-&alpha, ) and interleukin 10 (IL-10) cytokine, in the presence and absence of the inflammatory stimuli (bacterial endotoxin, lipopolysaccharide (LPS)), was measured using an ELISA assay. Our results revealed that the cellular response depended on the physical-chemical characteristics of the coatings. Copolymer-HA-Lf coatings led to low level of pro-inflammatory TNF-&alpha, the increased level of anti-inflammatory IL-10, and the polarization of THP-1 cells towards an M2 pro-reparative phenotype in the presence of LPS. These findings could have important potential for the development of composite coatings in implant applications.

Metallic nanostructure research attracted extensive attention from both scientific and industry community, leading to a wide variety of applications: from industrial ones including magnetic information storage and catalysis to new ones in photonics, imaging, and especially environmental and biomedical areas. Nevertheless, these promising applications imply a good knowledge and control over their properties (e.g., high surface area and good crystallinity). Within this context, this chapter will highlight the metallic nanostructure properties correlated to their applications in biomedicine. The most commonly used metallic nanostructures will be identified, and their fabrication methods and specific properties will be reviewed, with accent on their recent applications in the biomedical field.

Nanostructuring surfaces to engineer multifunctional interfaces is already routine work. This chapter will review fundamental knowledge regarding the origin of interfaces, their importance in correlation with the targeted applications, surface characterization methods, and present challenges in engineering-specific interfaces relevant for biomedical and environmental applications.

Graphene becomes the most popular 2-D nanomaterial since its recognition in 2004. Due to their physicochemical properties and wide range of applications, it becomes one of the most investigated materials. This chapter selectively summarizes the recent progress in fabrication and the use of graphene-based nanomaterials for various applications including biomedical and environmental. In particular, graphene-based detectors, sensors, and biosensors will be roughly discussed according to their sensing/detection mechanisms and targets. The utilization of graphene-based materials in drug delivery and nanomedicine will be also considered. Graphene-based materials and composites, developed for use in bioapplications and environmental monitoring and remediation, will be reviewed and perspectives presented.

Developing a controlled method for obtaining hybrid enzymatic-based interfaces for sensing application require the use of a multiuse, reusable sensor. By controlling the interface characteristics in terms of the surface chemistry, thickness, and roughness, a tailored response toward various toxic compounds can be obtained, regarding both materials used as active surfaces and fabrication methods. Herein, we report a preliminary study on using a laser-based method (i.e., matrix-assisted pulsed laser evaporation, or MAPLE) for obtaining active polymeric&ndash, enzymatic interfaces as hybrid or layered coatings for detecting toxic vapors. The MAPLE fabrication consisted of the simultaneous alternating evaporation of layers of polyethylenimine (PEI) and acetylcholinesterase (AchE) in order to obtain active surfaces as both hybrid PEI-AchE and a PEI/AchE layered coating, respectively. The deposition processes of the polymer and enzyme were carried out using a double-target system and a Nd:YAG pulsed laser, operating at 0.45 J/cm2 fluences with a wavelength of 266 nm and a repetition rate of 10 Hz. Fourier transform infrared spectroscopy revealed no significant changes in the functional groups of both hybrid and layered coatings compared with the initial material. The thickness and roughness, as well as the morphologies of the coatings revealed by atomic force microscopy and scanning electron microscopy showed coatings thicker than two &mu, m that had smooth surfaces and average roughness values below six nm. The sensors were tested with simulants for nerve gases and pesticides containing phosphonate ester groups, namely dimethyl methylphosphonate (DMMP) and diisopropyl methylphosphonate (DIMP), and a different sensitivity was shown to the selected chemical agents for each of the sensors. The best sensitivities for DMMP and DIMP obtained by using a PEI-AchE coated sensor are 65 kHz and 200 kHz, respectively, whereas the best sensitivity when using multilayered interfaces is 30 kHz and 10 KHz for DIMP and DMMP, respectively.

In the last decades, there is an increased interest in developing strategies for improving bio-interfaces in the field of orthopedic or dental implants. Various coating materials were used as nano and micro-structured interfaces to fine-tune the cellular response. Among these, ceria (CeO2) nanostructures are thought to improve the biointerface mechanical properties, but also to stimulate the regenerating tissue biochemical activity by neutralizing the oxidative stress and stimulating cells proliferation. Within this context, this work presents for the first-time pyramid-shaped nanostructured ceria films obtained by Pulsed Laser Deposition (PLD) targeting the early response of human osteosarcoma cells (SaOs-2). SEM and AFM images of the nanostructured surfaces revealed shapes from the quasi-pyramidal, with rounded edges and dimensions of 90–120 nm, to the sharp edges and dimensions up to 350 nm, obtained by varying the number of pulses. The transition from hydrophobic to moderate hydrophilic behavior, as well as the increase of the polar component for the samples with more prominent features, were correlated to the topographical characteristics and further to cell behaviour. The influence of pyramidal-shaped ceria on the in vitro biological performance of SaOs-2 cells was demonstrated by the differences in early adhesion and distribution of phenotype SaOs-2 cells. Nevertheless, as the adhesion and spreading characteristics are cell line specific, mesenchymal stem cells (MSCs) were used for comparing the different cytoskeleton response as response to the ceria nanostructure type. In perspective, the behavior of mesenchymal progenitor cells is foreseen to be analyzed in view of establishing an osteogenic response on these biomaterials and the best-suited processing approach in order to use them as substrates for future bone regeneration applications.

Understanding and controlling natural and synthetic biointerfaces is known to be the key to a wide variety of application within cell culture and tissue engineering field. As both material characteristics and methods are important in tailoring biointerfaces characteristics, in this work we explore the feasibility of using Matrix Assisted Pulsed Laser Evaporation technique for obtaining synthetic copolymeric biocoatings (i.e. poly(ethylene glycol)-block-poly(ɛ-caprolactone) methyl ether) for evaluating in vitro Vero and MC3T3-E1 pre-osteoblasts cell response. Characterization and evaluation of the coated substrates were carried out using different techniques. The Fourier transform infrared spectroscopy data demonstrated that the main functional groups in the MAPLE-deposited films remained intact. Atomic Force Microscopy images showed the coatings to be continuous, with the surface roughness depending on the deposition parameters. Moreover, the behaviour of the coatings in medium mimicking the pH and temperature of the human body was studied and corelated to degradation. Spectro-ellipsometry (SE) and AFM measurements revealed the degradation trend during immersion time by the changes in coating thickness and roughness. In vitro biocompatibility was studied by indirect contact tests on Vero cells in accordance with ISO 10993-5/2009. The results obtained in terms of cell morphology (phase contrast microscopy) and cytotoxicity (LDH and MTT assays) proved biocompatibility. Furthermore, direct contact assays on MC3T3-E1 pre-osteoblasts demonstrated the capacity of all analyzed specimens to support cell adhesion, normal cellular morphology and growth.

The typical foreign body response (FBR) to synthetic implants is characterized by local inflammation and tissue fibrosis. Silicone implants have been associated with the development of adverse capsular contraction (ACC); a form of excessive FBR to the material that often requires the replacement of the implant. It has been shown that surface roughening of silicone can reduce the prevalence of ACC, but the mechanisms remain poorly understood. Macrophages are key cells in FBR. They exert their control mainly by polarizing into pro-inflammatory (M1) or pro-healing (M2) cells. It is postulated that surface topography can reduce M1 polarization by limiting cell spreading and cytoskeleton organization. To test this hypothesis, we used KrF Excimer laser ablation with half-tone masks to produce convex and concave topographies with controlled surface dimensional parameters. Cells in convex and concave topographies were compared to cells in planar surfaces, with or without chemical polarization. We show that chemical polarization induced specific changes in the cell shape on planar substrates. Macrophage shape and size was different in concave and convex surfaces, but no correlation was found with the cell polarization state. The results highlight that chemical polarization of macrophages is associated with changes in the cell shape; however, topography-induced changes in macrophage shape could not be linked with a shift in macrophage polarization. Thus, the sole manipulation of cell shape does not seem to be the mechanism by which macrophage function could be controlled.

Current trends in designing medical and tissue engineering systems rely on the incorporation of micro- and nano-topographies for inducing a specific cellular response within the context of an aimed application. As such, dedicated studies have recently focused on understanding the possible effects of high and low density packed topographies on the behavior of epithelial cells, especially when considering their long-term viability and functionality. We proposed to use stair-like designed topographies with three different degrees of distribution, all created in polydimethylsiloxane (PDMS) as active means to monitor cell behavior. Our model cellular system was human bronchial epithelial cells (BEAS-2B), a reference line in the quality control of mesenchymal stem cells (MSCs). PDMS microtextured substrates of 4 &micro, m square unit topographies were created using a mold design implemented by a KrF Excimer laser. Varying the spacing between surface features and their multiscale level distribution led to irregular stairs/lines in low, medium and high densities, respectively. Profilometry, scanning electron and atomic force microscopy, contact angle and surface energy measurements were performed to evaluate the topographical and interface characteristics of the designed surfaces, while density-induced cellular effects were investigated using traditional cell-based assays. Our analysis showed that microstructure topographical distribution influences the adhesion profiles of epithelial cells. Our analysis hint that epithelial organoid formation might be initiated by the restriction of cell spreading and migration when using user-designed, controlled micro-topographies on engineered surfaces.

Among the multiple properties exhibited by lactoferrin (Lf), its involvement in bone regeneration processes is of great interest at the present time. A series of in vitro and in vivo studies have revealed the ability of Lf to promote survival, proliferation and differentiation of osteoblast cells and to inhibit bone resorption mediated by osteoclasts. Although the mechanism underlying the action of Lf in bone cells is still not fully elucidated, it has been shown that its mode of action leading to the survival of osteoblasts is complemented by its mitogenic effect. Activation of several signalling pathways and gene expression, in an LRPdependent or independent manner, has been identified. Unlike the effects on osteoblasts, the action on osteoclasts is different, with Lf leading to a total arrest of osteoclastogenesis. : Due to the positive effect of Lf on osteoblasts, the potential use of Lf alone or in combination with different biologically active compounds in bone tissue regeneration and the treatment of bone diseases is of great interest. Since the bioavailability of Lf in vivo is poor, a nanotechnology- based strategy to improve the biological properties of Lf was developed. The investigated formulations include incorporation of Lf into collagen membranes, gelatin hydrogel, liposomes, loading onto nanofibers, porous microspheres, or coating onto silica/titan based implants. Lf has also been coupled with other biologically active compounds such as biomimetic hydroxyapatite, in order to improve the efficacy of biomaterials used in the regulation of bone homeostasis. : This review aims to provide an up-to-date review of research on the involvement of Lf in bone growth and healing and on its use as a potential therapeutic factor in bone tissue regeneration.

Biocompatible and biodegradable coatings with controllable and tailored chemical and physical characteristics (i.e. morphology and roughness) are of great interest in bone related research applications. Within this research direction, in this work, a series of novel biodegradable coatings based on triblock copolymers poly(lactide-co-caprolactone)-block-poly(ethylene–glycol)-block-poly(lactide-co-caprolactone) (PLCL–PEG–PLCL) were obtained by matrix-assisted pulsed laser evaporation (MAPLE) and their morphological characteristics and roughness were modulated by varying target composition and laser fluence. The coatings were used for preliminary in vitro testing with MC3T3-E1 pre-osteoblasts. It was found that for a specific range of fluences, the main functional groups in the MAPLE-deposited thin films, as determined by Fourier transform infrared spectroscopy, are similar to the molecular structures of the initial material. Depending on the deposition parameters, significant changes in morphologies, i.e. material accumulation in the form of droplets, wrinkles, or carpet-like structures were revealed by atomic force microscopy (AFM) and scanning electron microscopy. The optimized coating characteristics were further correlated to MC3T3-E1 pre-osteoblasts response. The ability to control the morphology and to maintain unaltered the chemistry of the deposited material through MAPLE is an important step in creating functional bio-interfaces in the field of biomedical research and tissue engineering.

Whole cell optical biosensors, made by immobilizing whole algal, bacterial or mammalian cells on various supports have found applications in several fields, from ecology and ecotoxicity testing to biopharmaceutical production or medical diagnostics. We hereby report the deposition of functional bacterial layers of Micrococcus lysodeikticus (ML) via Matrix-Assisted Pulsed Laser Evaporation (MAPLE) on poly(diallyldimethylamonium) (PDDA)-coated-glass slides and their application as an optical biosensor for the detection of lysozyme in serum. Lysozyme is an enzyme upregulated in inflammatory diseases and ML is an enzymatic substrate for this enzyme. The MAPLE-deposited bacterial interfaces were characterised by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier-Transformed Infrared Spectroscopy (FTIR), Raman and optical microscopy and were compared with control interfaces deposited via layer-by-layer on the same substrate. After MAPLE deposition and coating with graphene oxide (GO), ML-modified interfaces retained their functionality and sensitivity to lysozyme's lytic action. The optical biosensor detected lysozyme in undiluted serum in the clinically relevant range up to 10μgmL-1, in a fast and simple manner.

The bipotent nature of the HepaRG cell line is a unique property among human hepatoma-derived cells. Cell treatment with specific differentiation inducers results in a mixture of hepatocyte- and biliary-like cells, accompanied by upregulation of liver-specific proteins, drug metabolizing enzymes, transcription regulators, membrane receptors or innate immune response effectors. These features make the HepaRG cells a suitable and handy replacement for primary hepatocytes, to study hepatic functions in vitro. However, cell differentiation is a long, variable process, requiring special culture conditions, while the resulting mixed cell populations is usually a major drawback. This process can potentially be controlled by interface characteristics, such as substrate topography. To screen for such novel substrates, we have first developed a new HepaRG cell line, designated as HepaRGDsRed, expressing the reporter gene DsRed. The fluorescent protein was expressed in hepatocyte- and not biliary-like cells, in a differentiation dependent-manner. We have further used replicated microstructured gradients of polydimethylsiloxane (PDMS) that allow three-dimensional manipulation in vitro, to monitor HepaRGDsRed differentiation in real time. We demonstrate that this approach enables the controlled assembly of viable hepatocyte-like cells for functional studies, which can be maintained in culture without loss of differentiation. The regulated expression of the DsRed reporter proved a valuable tool not only for rapid screening of novel cell growth substrates favoring cell differentiation, but also, to enrich the hepatocyte-like cell population by fluorescence-activated cell sorting to investigate liver-specific processes in vitro.

In this work, we report the synthesis of functional biocompatible piezoelectric (1 - x)Ba(Ti0.8Zr0.2)TiO3-x(Ba0.7Ca0.3)TiO3, x = 0.45 (BCZT45), thin films with high piezoelectric properties. Pulsed-laser-based techniques, classical pulsed-laser deposition and matrix-assisted pulsed-laser evaporation, were used to synthesize the BCZT45 thin films. The second technique was employed in order to ensure growth on polymer flexible Kapton substrates. The BCZT45 thin films grown by both techniques show similar structural properties and high piezoelectric coefficient coupling between the mechanical loading and electrical potential. While it has long been shown that the electrical potential favors biological processes like osteogenesis, the assessment of cell adhesion and osteogenic differentiation onto BCZT materials has not yet been demonstrated. We prove here for the first time that BCZT 45 coatings on Kapton polymer substrates provide optimal support for osteogenic differentiation of mesenchymal stem cells in the bone marrow.