Borosilicate Glass Surfaces Research Articles

A novel lytic phage infecting MDR Salmonella enterica and its application as effective food biocontrol.

Salmonella enterica is a foodborne pathogen associated with both typhoid and non-typhoid illness in humans and animals. This problem is further exacerbated by the emergence of antibiotic-resistant strains of Salmonella enterica. Therefore, to meet public health and safety, there is a need for an alternative strategy to tackle antibiotic-resistant bacteria. Bacteriophages or (bacterial viruses), due to their specificity, self-dosing, and antibiofilm activity, serve as a better approach to fighting against drug-resistant bacteria. In the current study, a broad-host range lytic phage phiSalP219 was isolated against multidrug-resistant Salmonella enterica serotypes Paratyphi from a pond water sample. Salmonella phage phiSalP219 was able to lyse 28/30 tested strains of Salmonella enterica. Salmonella phage phiSalP219 exhibits activity in acidic environments (pH3) and high temperatures (70°C). Electron microscopy and genome analysis revealed that phage phiSalP219 is a member of class Caudoviricetes. The genome of Salmonella phage phiSalP219 is 146Kb in size with 44.5% GC content. A total of 250 Coding Sequence (CDS) and 25 tRNAs were predicted in its genome. Predicted open reading frames (ORFs) were divided into five groups based on their annotation results: (1) nucleotide metabolism, (2) DNA replication and transcription, (3) structural proteins, (4) lysis protein, and (5) other proteins. The absence of lysogeny-related genes in their genome indicates that Salmonella phage phiSalP219 is lytic in nature. Phage phiSalP219 was also found to be microbiologically safe (due to the absence of toxin or virulence-related genes) in the control of Salmonella enterica serovar Typhimurium infections in the ready-to-eat meat and also able to eradicate biofilm formed by the same bacterium on the borosilicate glass surface.

Determining the dispersion time in Staphylococcus epidermidis biofilm using physical and molecular approaches

Despite being an innocuous commensal of human skin and mucous membranes, Staphylococcus epidermidis, infects surgical wounds and causes infections through biofilm formation. This study evaluates, in a time-dependent experiment, the self-dispersion of S. epidermidis CIP 444 biofilm when formed on borosilicate glass (hydrophilic) and polystyrene (hydrophobic) surfaces, using physical and molecular approaches. During a seven-day period of incubation, absorbance measurement revealed a drop in biofilm optical density on both studied surfaces on day 4 (0.043–0.035 nm/cm2, polystyrene), (0.06–0.053 nm/cm2, borosilicate glass). Absorbance results were correlated with crystal violet staining that showed a clear detachment from day 4. The blue color increases again on day 7, with an increase in biofilm optical density indicating the regeneration of the biofilm. Changes in gene expression in the S. epidermidis biofilm were assessed using a real-time reverse transcription-polymerase chain reaction. High expression of agr genes was detected on days 4 and 5, confirming our supposition of dispersion in this period, autolysin genes like atlE1 and aae were upregulated from day 3 until day 6 and the genes responsible for slime production and biofilm accumulation, were upregulated on days 4, 5, and 6 (ica ADBC) and on days 5, 6 and 7 (aap), indicating a dual process taking place. These findings suggest that S. epidermidis CIP 444 biofilms disperse at day 4 and reform at day 7. Over the course of the seven-day investigation, 2-ΔΔCt results showed that some genes in the biofilm were dramatically enhanced while others were significantly decreased as compared to planktonic ones.

A study on mechanical and tribological properties of eco-friendly synthesized ZrO2-doped borosilicate glasses

The research article aims to investigate the mechanical and tribological characteristics of bioactive glass specimens comprising 31B2O3-20SiO2-24.5Na2O-(24.5-x) CaO and xZrO2 (mol%). This glass system was partially derived from bio-waste, with varying concentrations of Zirconia (ZrO2) represented x (x = 0, 1, 3, and 5). The specimens were fabricated using the traditional melt-quench method. Mechanical studies like hardness and compressive strength were measured using Vickers hardness tester and universal tensile machine respectively, while a pin-on-disk tribometer was used to analyze the tribological characteristics. All the specimens were soaked in SBF for a week to assess in-vitro bioactivity. The research findings indicate that Zirconia inclusion resulted in a significant reduction in the intensity of hydroxyapatite peaks of FTIR and XRD spectra, suggesting a decrease in bioactivity. However, it concurrently resulted in increased glass hardness, with the highest value (∼7.55 GPa) observed in the BSG-5 glass sample. Similarly, compressive strength results demonstrated maximum strength in BSG-5 glass specimen, with a value of approximately ∼132 MPa. Moreover, the tribological properties of the glass system were enhanced, evident from the reduced coefficient of friction and specific wear rate. Notably, the BSG-5 glass specimen exhibited the least wear coefficient of 0.018 mm3/N-m at a track radius of 40 mm and a load of 15N. These findings were further supported by SEM images of the worn-out ZrO2-Doped Borosilicate Glass surface. Overall, the results suggest that the addition of Zirconia to borosilicate glass holds promise for improving its mechanical and tribological characteristics. However, this enhancement comes at the expense of its bioactivity. Consequently, the modified glass system presents a cost effective viable option for various applications, particularly in load-bearing and dental applications.

Combined experiments and atomistic simulations for understanding the effect of ZnO on the sodium silicate and sodium borosilicate glass network

Combined experiments and molecular dynamics (MD) simulations were performed over wide range of glass compositions to understand the improved durability of borosilicate glass with ZnO addition. A significant change in glass structure was monitored from short range and intermediate range order parameters. The MD results were found to be in good agreement with the experimental data for Young's Modulus, glass transition temperature, and leaching. Both experiments and MD simulations report the enhanced chemical durability of glass with ZnO addition. Low R (Na2O/B2O3) and high K (SiO2/B2O3) of ZnO doped sodium borosilicate (Zn–NBS) glass surface compared to bare NBS represents the more stable structure of glass surface for Zn–NBS than NBS. The enhanced chemical resistivity of Zn–NBS was established from the increasing activation energy for diffusion of Na ions. The combined experiments and MD simulations disclose many interesting microstructure and dynamics due to the presence of ZnO in the glass.

Direct Femtosecond Laser Processing for Generating High Spatial Frequency LIPSS (HSFL) on Borosilicate Glasses with Large-Area Coverage

Large-area nanostructuring of glasses using intense laser beams is a challenging task due to the material’s extreme non-linear absorption of laser energy. Precise optimization of the process parameters is essential for fabricating nanostructures with large-area coverage. In this study, we report the findings on creating high-spatial-frequency LIPSS (HSFL) on borosilicate glass through direct laser writing, using a femtosecond laser with a wavelength λ = 800 nm, pulse duration τ = 35 fs, and repetition frequency frep = 1 kHz. We measured the single-pulse ablation threshold and incubation factor of Borosilicate glasses to achieve high-precision control of the large-area surface structuring. Single-spot experiments indicated that, when there was higher fluence and a larger number of irradiated laser pulses, a melt formation inside the irradiated area limited the uniformity of LIPSS formation. Additionally, the orientation of the scan axis with the laser beam polarization was found to significantly influence the uniformity of LIPSS generated along the scan line, with more redeposition and melt formation when the scan axis was perpendicular to the laser beam polarization. For large-area processing, the borosilicate glass surface was scanned line-by-line by the laser beam, with a scan orientation parallel to the polarization of the laser. The optical characterization revealed that the transmittance and reflectance of the borosilicate glass decreased significantly after processing. Additionally, the surface’s wettability changed from hydrophilic to super-hydrophilic after processing. These chemical contamination-free and uniformly distributed structures have potential applications in optics, microfluidics, photovoltaics, and biomaterials.

The impact of temperature on heated liquid films: Crater and jetting impact dynamics

The droplet impact phenomena onto liquid films are a field extensively researched for over a century, which are driven by many practical applications such as heat exchangers, internal combustion engines and spray cooling. Despite the extensive work on wetted surfaces, the influence of temperature on droplet outcome, local evaporation/boiling effects, and liquid film stability has been overlooked in the literature. Therefore, the main objective of this work is to evaluate the influence of the liquid film temperature on the crater and jet dynamics. The experimental setup was designed for this purpose, in which a borosilicate glass surface that contains the liquid film is placed over an aluminium block with embedded cartridge heaters, heating it by conduction. Water, n-decane and n-heptane are the fluids adopted for the experiments due to their differences in thermophysical properties and saturation temperature. Different conditions are considered, which include two dimensionless thicknesses, h∗=1.0 and h∗=1.5, and a range of dimensionless temperatures, θ=0, θ=0.2, θ=0.4 and θ=0.6. Qualitative and quantitative analyses are performed regarding crater evolution, and central jet height and breakup measurements, respectively. Evaporation rate measurements are required due to the influence on the liquid film thickness variation. Qualitative results show that temperature differences promote the formation of recirculation zones near the impact surface and the crater boundaries, as well as the influence on the crater shape and curvature. In terms of the quantitative analysis, the central jet height measurements for the n-heptane and n-decane reveal that higher values of the dimensionless temperature lead to an increase in the jet height, as well as promoting and increasing the occurrence and number of secondary droplets, respectively. Water follows a similar trend with the exception of θ=0.2, which can be explained by a time scale analysis.

Understanding the Adsorption and Desorption of Sitagliptin Phosphate Monohydrate on SS2343, Glass, and PTFE Using QCM-D and Raman Spectroscopy.

Cross-contamination during pharmaceutical drug manufacturing can result in expensive recalls. To counter that, companies spend significant time and resources to ensure equipment cleanliness, often relying on the compound solubility data in various solvents as the main indicator of cleaning success. The aim of this work is to provide an alternative way to analyze the fouling and cleaning of surfaces in pharmaceutical manufacturing processes by using the quartz crystal microbalance with dissipation (QCM-D) and Raman spectroscopy. In this study, we chose an active pharmaceutical ingredient (API), sitagliptin phosphate monohydrate (SIT), as the model drug compound and observed its adsorption and desorption on stainless steel (SS2343), borosilicate glass (glass), and polytetrafluoroethylene (PTFE) surfaces. SIT was selected as the model API since it is a product manufactured on a large scale and is part of the widely used dipeptidyl peptidase-IV inhibitor class of oral hypoglycemics used to treat type 2 diabetes mellitus, while the chosen surfaces mimic the wall materials of manufacturing equipment and components such as reactors, transfer lines, and valves. Both the QCM-D and Raman spectroscopy results show the highest physisorption on PTFE, followed by SS2343 and glass. Additionally, QCM-D revealed a harder removal of SIT from SS2343 compared to glass and PTFE. Raman analysis of the chemical interactions disclosed C-F and C═O bond interactions between SIT and the surfaces, and the lack of a peak shift suggested dipole-dipole interactions. Furthermore, contact angle measurements indicate that hydrophobic attraction contributed to SIT adhesion to the PTFE surface. Subsequently, SIT coverage upon deposition on a PTFE surface has a significantly smaller surface area than on SS2343 and glass due to surface hydrophobicity, hence resulting in a longer removal time. These results provide a practical use of QCM-D and Raman spectroscopy to enhance the understanding of fouling and improve the cleaning of complex small molecules on relevant surfaces during the pharmaceutical manufacturing process.

Improved magnetorheological finishing process with arc magnet for borosilicate glass

ABSTRACT In the process of magnetorheological polishing of planar optical elements, in order to solve the problem of uneven material removal rate and improve the polishing efficiency of planar optical elements. The finite element simulation was used to optimize the shape of the permanent magnet, and an arc permanent magnet was designed with a radius of curvature of 55 mm. The magnetic flux density of the arc permanent magnet has a Gaussian distribution, which effectively attenuates the effect of linear velocity on polishing. The arc permanent magnet is beneficial to achieve a more uniform material removal and better processing quality. The experiments are conducted on the borosilicate glass using the recent arc permanent magnet and existing planar permanent magnet. The experimental results show that the arc permanent magnets can reduce the average surface roughness value from 286 nm to 16 nm and the standard deviation of surface roughness to 0.92 under the same processing parameters. Therefore, the analysis of the borosilicate glass surface verifies that the designed arc permanent magnets can effectively improve surface accuracy and surface topography .

Bilayer Silver Precipitation in Glass Formed by Alternate Doping of Silver and Sodium Ions and Additive Voltage Application

The solid-state ion exchange method enables to dope metal ions to alkali-containing glass surfaces. When silver is used as a dopant material, a silver precipitation layer is formed in the silver-doped area by additive voltage application. Because of the high electrical conductivity, the precipitation layer can be used as an internal wiring in a glass substrate. In this study, we tried to form bilayer wiring in a glass substrate. For the bilayer precipitation, two silver-doped areas are necessary to be separated by a silver-undoped area. Therefore, silver, sodium and silver ions were sequentially doped to a borosilicate glass surface. To prevent silver ions being mixed into the sodium-doped area, the diffusion behaviors of two ionic species were numerically analyzed. The temperature dependences of their diffusion coefficients were also determined by comparing experimental and numerical results carried out under various temperature conditions. Calculated results showed that low temperature doping of sodium ions to silver-doped area is preferable. By adopting suggested conditions, the formation of electrically-insulated two silver precipitation layer was achieved.

Modelling and parameter estimation of diethyl phthalate partitioning behaviour on glass and aluminum surfaces

The knowledge of the partitioning behaviour of semi-volatile organic compounds (SVOCs), such as phthalates, between different materials and their surrounding air is of extreme importance for quantifying levels of human exposure to these compounds, which have been associated with adverse health effects. Phthalates’ partitioning behaviour also represents a key property for modelling and assessing polymer degradation mechanisms associated with plasticiser loss. However, the characterisation of phthalates partitioning behaviour has been reported only for a limited number of compounds, mainly involving di-2-ethylhexyl phthalate (DEHP), di-isononyl phthalate (DINP) and di-isodecyl phtahalate (DIDP), while the characterisation of diethyl phthalate (DEP) partitioning has been overlooked. As one of the first plasticisers employed in the production of semi-synthetic plastics produced industrially in the late 19th and early 20th century, DEP plays an important role for understanding stability issues associated with historically significant artefacts in museum collections and archives. Here we show that the partitioning behaviour of DEP between borosilicate glass and aluminum surfaces and their surrounding air can be described by an exponential function of temperature, presenting a model to describe this relationship for the first time. Model parameters are estimated using nonlinear regression from experimental measurements acquired using 109 samples which have been equilibrated at different temperatures between 20 and 80 °C in sealed environments. Measured partition coefficients have been predicted accurately by our proposed model. The knowledge of DEP equilibrium distribution between adsorptive surfaces and neighbouring environments will be relevant for developing improved mathematical descriptions of degradation mechanisms related to plasticiser loss.

Solar-TiO2 immobilized photocatalytic reactors performance assessment in the degradation of methyl orange dye in aqueous solution

Heterogeneous photocatalysis with titanium dioxide (TiO2) nanoparticles (NPs) has been demonstrated an emerging semiconductor material and widely been used in the treatment of wastewater due to is its high photocatalytic activity. In this study, TiO2 NPs with and without hydrolysis were synthesized by sol–gel and heat treatment methods. About 67 times higher surface area was obtained for TiO2 NPs synthesized with hydrolysis as compared to without hydrolysis. The X-ray diffraction showed an increased amount of anatase phase of TiO2 NPs with hydrolysis whereas the rutile phase of TiO2 NPs was obtained without hydrolysis. Immobilized-TiO2 NPs borosilicate glass (BG), cement coated borosilicate glass (CCBG), and steel wire mesh (SWM) reactors were constructed and the photocatalytic performance of TiO2 NPs was investigated to the degradation of methyl orange (MO) dye under solar irradiation. The photocatalytic removal of 10 mg/L MO dye was 97.8%, 88.6%, and 21.5%, respectively, at the same dose of immobilized-TiO2 on BG, CCBG, and SWM surfaces at pH 6.2 with 5 h of contact time. The kinetic study showed a pseudo-first-order reaction model fitted the best for MO dye removal. The increase of dye concentration decreases the performance of BG reactor, whereas, the addition of oxidant H2O2 increases the performance of BG reactor. The lowest TiO2 NPs loss from the study was observed for BG reactor (10.78%). This study indicates that the solar-TiO2 immobilized borosilicate glass reactor has high potential in the treatment of toxic compounds in textile wastewater.

Gas ejection mechanism of glass structuring induced by nanosecond laser pulses

In this work, results on a new laser-induced mechanism of microstructures formation on the surface of borosilicate glass are presented. The samples are fabricated by melt quenching method and consist of 50% SiO2, 20% Al2O3, 20% B2O3, 5% CaO, 2% Li2O, 3% MgO (in wt.%). Irradiation at 266 nm delivered by Nd:YAG nanosecond system is used to modify the glass surface. It is found that this processing may result in the formation of voids in the irradiated area that have submicron mean diameter. The effect is observed at fluences below the ablation threshold. Different laser fluences and pulse number are applied to estimate their role on the induced surface morphology. It is observed that voids are also observed in the remaining material after ablation of the irradiated zone at high fluences. In this regime, glass structure modifications can also be observed under the glass surface at depths that may reach 100 µm. Based on measurements by differential thermal analysis equipped by mass spectrometer is concluded that the void formation is related to emission of gas phase from the glass induced by the laser heating.

Photografting and Patterning of Poly(ethylene glycol) Methacrylate Hydrogel on Glass for Biochip Applications.

An efficient procedure for chemical initiator-free, in situ synthesis of a functional polyethylene glycol methacrylate (PEG MA) hydrogel on regular glass substrates is reported. It is demonstrated that self-initiated photografting and photopolymerization driven by UV irradiation can yield tens of nanometer-thick coatings of carboxy-functionalized PEG MA on the aldehyde-terminated borosilicate glass surface. The most efficient formulation for hydrogel synthesis contained methyl methacrylic acid (MAA), 2-hydroxyethyl methacrylate (HEMA), and PEG methacrylate (PEG10MA) monomers (1:1:1). The resulting HEMA/PEG10MA/MAA (HPMAA) coatings had a defined thickness in the range from 11 to 50 nm. The physicochemical properties of the synthesized HPMAA coatings were analyzed by combining water contact angle measurements, stylus profilometry, imaging null ellipsometry, and atomic force microscopy (AFM). The latter technique was employed in the quantitative imaging mode not only for direct probing of the surface topography but also for swelling behavior characterization in the pH range from 4.5 to 8.0. The estimated high swelling ratios of the HPMAA hydrogel (up to 3.2) together with its good stability and resistance to nonspecific protein binding were advantageous in extracellular matrix mimetics via patterning of fibronectin (FN) at a resolution close to 200 nm. It was shown that the fabricated FN micropatterns on HPMAA were equally suitable for single-cell arraying, as well as controlled cell culture lasting at least for 96 h.

Bactericidal surfaces prepared by femtosecond laser patterning and layer-by-layer polyelectrolyte coating

Antimicrobial surfaces are important in medical, clinical, and industrial applications, where bacterial infection and biofouling may constitute a serious threat to human health. Conventional approaches against bacteria involve coating the surface with antibiotics, cytotoxic polymers, or metal particles. However, these types of functionalization have a limited lifetime and pose concerns in terms of leaching and degradation of the coating. Thus, there is a great interest in developing long-lasting and non-leaching bactericidal surfaces. To obtain a bactericidal surface, we combine micro and nanoscale patterning of borosilicate glass surfaces by ultrashort pulsed laser irradiation and a non-leaching layer-by-layer polyelectrolyte modification of the surface. The combination of surface structure and surface charge results in an enhanced bactericidal effect against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The laser patterning and the layer-by-layer modification are environmentally friendly processes that are applicable to a wide variety of materials, which makes this method uniquely suited for fundamental studies of bacteria-surface interactions and paves the way for its applications in a variety of fields, such as in hygiene products and medical devices.

Integrative treatment of anti-tumor/bone repair by combination of MoS2 nanosheets with 3D printed bioactive borosilicate glass scaffolds

Malignant bone tumors have caused great obstacles and serious illnesses for tumor recurrence and difficulty in reconstructing and repairing large defects after tumorectomy. Additionally, long-term efficacy, satisfactory biocompatibility and excellent properties for anti-tumor agents are necessary in the biomedical field. To solve these problems, a novel idea has been proposed on building an integrative anti-tumor/bone repairing scaffold by covering photothermal therapy (PTT) composite MoS2-PLGA film on the surface of borosilicate bioactive glass (BG). In our study, the MoS2-integrated composite BG (BGM) scaffolds can rapidly and effectively elevate temperature, and they exhibited excellent photothermal stability, under 808 nm laser irradiation. Notably, the BGM scaffolds can effectively reduce the viability of osteosarcoma cells (MNNG/HOS) in vitro as well as inhibit the tumor growth in nude mice. Furthermore, the prepared BGM scaffolds can stimulate the proliferation and differentiation of rat bone mesenchymal stem cells (rBMSCs), upregulate the expression of osteogenesis-related genes (Runx-2, OCN and Col-I) in vitro and promote in vivo bone repair in critical-sized rat calvarial defects. Therefore, the novel MoS2-integrated composite BG scaffolds are highly promising for the treatment of tumor-related bone defects, offering ideas for the manufacture of new materials in the tissue engineering field.

The impacts of LPCVD wrap-around on the performance of n-type tunnel oxide passivated contact c-Si solar cell

In this paper, Tunnel Oxide Passivated Contact (TOPCon) silicon solar cells with the industrial area (244.32 cm2) are fabricated on N-type silicon substrates. Both the ultra-thin tunnel oxide layer and phosphorus doped polycrystalline silicon (polysilicon) thin film are prepared by the LPCVD system. The wrap-around of polysilicon is observed on the surface of borosilicate glass (BSG). The polysilicon wrap-around can form a leakage current path, thus degrades the shunt resistance of solar cells, and leads to the degradation of solar cell efficiency. Different methods are adopted to treat the polysilicon wrap-around and improve shunt resistance of solar cells. The experimental results indicate that a chemical etching method can effectively solve the problem of polysilicon wrap-around and improve the performance of solar cells. Finally, a conversion efficiency of 22.81% has been achieved by our bifacial TOPCon solar cells, with Voc of 702.6 mV, Jsc of 39.78 mA/cm2 and FF of 81.62%.

Reciprocating magnetorheological polishing method for borosilicate glass surface smoothness

A new reciprocating magnetorheological (MR) method for polishing a flat borosilicate glass surface is proposed. A reciprocating MR polishing tester was designed to polish borosilicate glass, in which supplying MR polishing fluid uniformly could yield a flatter surface on the workpiece. The MR polishing fluid was prepared according to specific test requirements and the rheological properties and precipitation rate were measured. The mechanism for polishing borosilicate glass was evaluated further by analyzing the surface morphology and surface profile. The transparency of the glass surface was enhanced with an improvement of surface quality with pre-processing and reciprocating MR polishing process. The results demonstrated the effectiveness of the reciprocating MR polishing method, which could be used for polishing borosilicate glass.

Evolution of HF etching rate of borosilicate glass by friction-induced damages

It is well-known that the HF etching of oxide glass is of critical importance for various functional and engineering applications, but the detailed etching rate and mechanisms still remain elusive. In this study, the effects of friction-induced damages on HF etching of borosilicate glass have been studied. Various friction-induced damages at borosilicate glass surfaces are achieved by rubbing against a stainless-steel ball under various conditions via a reciprocating tribometer in humid air. The experimental results show that the HF etching rate of borosilicate glass is very sensitive to the type of friction-induced damages. The decreasing of etching rate of friction-induced damages at glass surface is as follows: pristine glass > scratch zone > cracking zone > debris zone. Based on the analyses of the local structure and composition evolution, it is indicated that compared to the pristine and scratched borosilicate glass, the metal ions (such as Al3+) of borosilicate glass in the cracking zone may play important roles in reducing its HF etching rate, while the well-packaged Fe-containing wear debris at borosilicate glass surface can significantly suppress its HF etching rate. These results may help design and optimize the HF etching of oxide glasses for various functional and engineering applications.

Evaluation of capillary wetting performance of micro-nano hybrid structures for open microgrooves heat sink

Thermal management for various applications have promoted the development and in-depth investigations of open capillary microgrooves. Micro-nano hybrid grooves heat sink (combined of microgrooves and Ti nano-coatings) is proposed in this study. The wicking performance, which in terms of capillary wetting length, capillary wetting uniformity and capillary performance parameter determines the design and thermal management of the microgrooves heat sink. In this study, wicking performance from micro-nano hybrid grooves heat sink has been studied experimentally, with theoretical analysis. The wicking performance of the smooth and fully coated with Ti nano-coatings on borosilicate glass surfaces (3 different thicknesses), with 3 different grooves dimensions, has been studied in detail. A quantitative and automatic optical method using IR imaging is applied in this study to identify the capillary wetting length (dryout point) through the whole width of the microgrooves, even in each groove, based on the pixel differences of an IR image. Results show that the Ti nano-structured surfaces significantly improve the capillary wetting performance, compared with bare surfaces.

Improvements of Microcontact Printing for Micropatterned Cell Growth by Contrast Enhancement.

Patterned neuronal cell cultures are important tools for investigating neuronal signal integration, network function, and cell–substrate interactions. Because of the variable nature of neuronal cells, the widely used coating method of microcontact printing is in constant need of improvements and adaptations depending on the pattern, cell type, and coating solutions available for a certain experimental system. In this work, we report on three approaches to modify microcontact printing on borosilicate glass surfaces, which we evaluate with contact angle measurements and by determining the quality of patterned neuronal growth. Although background toxification with manganese salt does not result in the desired pattern enhancement, a simple heat treatment of the glass substrates leads to improved background hydrophobicity and therefore neuronal patterning. Thirdly, we extended a microcontact printing process based on covalently linking the glass surface and the coating molecule via an epoxysilane. This extension is an additional hydrophobization step with dodecylamine. We demonstrate that shelf life of the silanized glass is at least 22 weeks, leading to consistently reliable neuronal patterning by microcontact printing. Thus, we compared three practical additions to microcontact printing, two of which can easily be implemented into a workflow for the investigation of patterned neuronal networks.