Laser Induction Research Articles

Controlling the laser induction and cutting process on polyimide films for kirigami-inspired supercapacitor applications

The recently emerging laser-induced graphene (LIG) technology, with one-step processing and designable features, has been widely used in the fabrication of wearable/portable electronics. Herein, by taking inspiration from kirigami, we designed a stretchable supercapacitor (SC) step by step through controlling laser induction and cutting process on the polyimide (PI) film, with the use of one single CO2 laser source. Firstly, the carbonized basic geometric units of lines were produced on PI films to investigate the processing-structure relationships. Then, the complex photothermal conversion and heat transfer progress involved in the carbonized process were simulated by a photothermal model. Both experimental and theoretical results suggested that the laser power, scan rate and focus condition have great influence on the size, shape and morphology of the carbonized lines. Finally, we optimized the parameters of laser induction and cutting process to fabricate the kirigami-inspired SCs with reliable electrochemical properties and editable mechanical flexibility, showing great potential in the field of flexible electronics.

One-step laser induced conversion of a gelatin-coated polyimide film into graphene: Tunable morphology, surface wettability and microsupercapacitor applications

Latest advances have witnessed the laser induction process on polyimide (PI) films for the formation of porous graphene. Herein, a fully converted graphene film was prepared by Nd:YAG laser scribing a gelatin coated PI film. It was found that the gelatin played the role of “shield” well in absorbing intense laser impact and benefit for the surface morphology modulation. Laser treatment lower than a critical fluence point of ~4.00 J mm−2 contributed to a crater-like surface morphology due to the dispersed nature of Nd:YAG laser beam. By tuning laser fluence above the threshold, carbonized surface turned into continuous morphology. A fluid dynamics process accompanied by outgassing occurred during the carbonization, and the surface morphology gradually varied from stretched droplets to porous strips and finally to amorphous porous structures. The morphology evolution in combination with surface chemistry is responsible for the significant wettability transition from superhydrophobic to superhydrophilic, and a Janus superhydrophobic/superhydrophilic surface wettability was achieved under a laser fluence of ~8.00 J mm−2. Eventually, microsupercapacitors (MSCs) were fabricated to show the great potential of our prepared graphene in flexible electronics.

Laser-Induced Graphene Electrochemical Immunosensors for Rapid and Label-Free Monitoring of Salmonella enterica in Chicken Broth.

Food-borne illnesses are a growing concern for the food industry and consumers, with millions of cases reported every year. Consequently, there is a critical need to develop rapid, sensitive, and inexpensive techniques for pathogen detection in order to mitigate this problem. However, current pathogen detection strategies mainly include time-consuming laboratory methods and highly trained personnel. Electrochemical in-field biosensors offer a rapid, low-cost alternative to laboratory techniques, but the electrodes used in these biosensors require expensive nanomaterials to increase their sensitivity, such as noble metals (e.g., platinum, gold) or carbon nanomaterials (e.g., carbon nanotubes, or graphene). Herein, we report the fabrication of a highly sensitive and label-free laser-induced graphene (LIG) electrode that is subsequently functionalized with antibodies to electrochemically quantify the food-borne pathogen Salmonella enterica serovar Typhimurium. The LIG electrodes were produced by laser induction on the polyimide film in ambient conditions and, hence, circumvent the need for high-temperature, vacuum environment, and metal seed catalysts commonly associated with graphene-based electrodes fabricated via chemical vapor deposition processes. After functionalization with Salmonella antibodies, the LIG biosensors were able to detect live Salmonella in chicken broth across a wide linear range (25 to 105 CFU mL-1) and with a low detection limit (13 ± 7 CFU mL-1; n = 3, mean ± standard deviation). These results were acquired with an average response time of 22 min without the need for sample preconcentration or redox labeling techniques. Moreover, these LIG immunosensors displayed high selectivity as demonstrated by nonsignificant response to other bacteria strains. These results demonstrate how LIG-based electrodes can be used for electrochemical immunosensing in general and, more specifically, could be used as a viable option for rapid and low-cost pathogen detection in food processing facilities before contaminated foods reach the consumer.

Laser Induction of Signal Networks in Adaptation and Regeneration: Investigation of the Contribution of Endogenous Photoreceptors and Thermoreceptors

A comparative analysis of laser-induced signal networks in rat tumors and in cultured tumor cells is performed. The time threshold of laser exposure which enhances the efficiency of chemotherapy is evaluated. The possibility of the involvement of epigenetic processes in the signal network as a result of translocation of the endogenous photoreceptor cytoglobin in a cell nucleus is demonstrated. Such translocation is assumed to be induced by the local overheating of a chromophore, which modulates the nuclear membrane surface and facilitates cytoglobin transfer into the hydrophobic phase.

In situ formation of phosphorus-doped porous graphene via laser induction.

Heteroatom-doped graphene exhibits high energy storage performance when used as an active electrode, and which can been applied to various advanced applications, but challenging in synthesis, e.g., hazardous chemical reagents usage, difficult processing steps, and energy consumption. We demonstrated a ready, rapid and normal method for generating phosphorus-doped graphene (LIPG) using a CO2 laser on polyimide (PI) substrate mixed with ammonium polyphosphate (APP) in ambient air. LIPG was approved and successfully synthesized via TEM, SEM, XRD and Raman observations. Moreover, we discussed the flame-retardant performance of APP for synthesizing LIPG on PI substrates, increasing the degree of graphitization. Furthermore, LIPG prepared using supercapacitors as an electrode showed good electrochemical performance. Remarkably, the highest specific capacitance of porous LIPG is about 206 F g−1 at the current density of 0.025 A g−1, the value is about 2 times higher than those undoped laser induced graphene (LIG). Such great performance of the LIPG electrode material is attributed to the formation of a hierarchical porous structure, phosphorus atom doping, and manufacturing deficiency. Hence, LIPG showed considerable potential in the electrochemical application field. The proposed preparation of LIPG is best suited for synthesis and applicable to the doping of other heteroatoms doped into graphene.

Comparison of marginal accuracy and internal fit of cast nickel chromium and metal laser-sintered crowns: An in vitro study

Purpose: The aim of this study was to evaluate and compare the marginal accuracy and internal fit of crowns fabricated by direct metal laser sintering, induction casting, and centrifugal casting. Materials and Methods: An acrylic resin analog of the right maxillary first molar was prepared with a total convergence angle of 6° and an occlusal reduction of 1.5 mm and 0.8 mm shoulder finish line. Thirty impressions of the analog tooth were obtained from the definitive die, n = 10 for each group. Wax patterns were fabricated and casting was done using an induction casting machine and centrifugal gas torch method, and for the direct metal laser-sintering group the dies were scanned and crown fabricated using EOS sintering machine. The marginal and internal gaps were estimated by measuring the cement thickness using a stereomicroscope. The mean value was determined and P values were obtained using a one-way analysis of variance (ANOVA) test. Student’s t test was used to determine the differences between the three groups. Results: The mean marginal and internal gaps were 59.82 ± 5.21 μm and118.69 ± 20.23 μm in the direct metal laser-sintering group, 116.13 ± 7.88 μm and 136.94 ± 13.50 μm in induction casting group, and 116.87 ± 7.46 μm and 133.77 ± 10.63 μm in centrifugal casting group, respectively. Conclusion: Under the limitation of this in vitro study, the marginal and internal gaps of DMLS group are better than centrifugal and induction casting groups.

核极限学习机和激光诱导荧光技术在食用油识别中的应用

核极限学习机和激光诱导荧光技术在食用油识别中的应用

Hydrofluoroether Impurities—Chemical Detection Using a Deep Learning Laser Speckle Contrast Evolving Spiking Neural Network

Hydrofluoroether (HFE) impurities detection is an issue related to detecting chemical contamination within a high volume manufacturing (HVM) chiller caused by a rapid emulated environmental attack. The aftereffects of the cycle emulated attack may eventually create a micro-crack in the heat-exchanger. This event eventually causes the contamination of HFE due to multiple chemical interactions. This study proposes a new classification methodology to detect HFE chemical impurities using induction by a 532nm laser. The purpose of the laser induction is to leverage its laser speckle contrast attributes and amplify its detection. One of the reasons for choosing the 532nm laser spectrum is its highest quantum efficiency. Once amplification of detection is achieved, the detector tends to be in a highly sensitive mode due to low marginality to differentiate between two different conditions. This mode is prone to be stochastic. Thus, a new form of architecture known as Deep Learning Laser Speckle Contrast Evolving Spiking Neural Network (DL-LSC-ESNN) is proposed. The architecture utilizes speckle contrast domain conversion, dimensional additivity of the receptive neuron of evolving spiking neural network (ESNN), followed by the strength of Convolution Neural Network (CNN) feature extraction (FE) capability. Ultimately, the evolving and adaptive ability of ESNN is assimilated and integrated seamlessly. CNN acted to extract only an important spike train, and the result is its essences of important spikes or spike feature maps. The spike feature maps are then fed into the ESNN neuron repository, which either assimilates or creates a new neuron repository. The proposed methods show significant improvement in the accuracy of detection against multiple baseline state of the art CNN architecture and ultimately demonstrated its capability to detect real-time contamination of HFE thus improved the detection rate significantly for the HVM environment.

Experimental and numerical study of the influence of induction heating process on build rates Induction Heating-assisted laser Direct Metal Deposition (IH-DMD)

Direct Metal Deposition (DMD) technology proves advantageous in complex and precise component fabrications. Nevertheless, the typical productivity rate of the DMD process is not sufficient for fabricating large components. In this paper, the induction heating (IH) technique is presented to address this issue by assisting the DMD process by increasing the build-up rate.For this purpose, the influences of different laser processing and induction heating factors are investigated to provide the information required for designing a suitable IH setup that is capable of integrating into the DMD process. Furthermore, a finite element simulation of IH is carried out using the COMSOL software package and the results are accordingly verified against experimental data. This helps design a Hybrid Induction DMD (IH-DMD) process by identifying a correlation between induction parameters and generated heating temperature on the component surface.This paper presents the implementation setup of IH-DMD discusses its limitations. In a final setup, deposition of Inconel 625 powder material on the structure steel S235 with an IH-DMD process is examined to show the improvement gained. This includes different powder feed rates, scan speeds, and spot diameters.The results demonstrate the important role of the coil profile, magnetic flux concentrator, coupling gap, electric current in the coil, and coil shield to achieve a sufficient heating rate and stable IH-DMD coating process. The deposition rates and clad geometry are characterized. By employing IH-DMD, the coating deposition can be improved by a factor of three.

The potent integrin antagonist THR‐687 is a promising next‐generation drug candidate for the treatment of multifactorial retinal diseases

AbstractPurposeIntegrins are implicated in eye diseases such as diabetic retinopathy (DR) and wet age‐related macular degeneration (AMD). Targeting integrins can attenuate the main pathologic hallmarks like vascular leakage, inflammation, gliosis, angiogenesis and fibrosis. Previously, we showed that the integrin antagonist, THR‐687, has potent anti‐angiogenic properties in the cynomolgus choroidal neovascularization (CNV) model. The goal of this study was to further investigate the therapeutic effect of THR‐687 in the diabetic streptozotocin (STZ)‐induced rat model and the cynomolgus CNV model.MethodsIn STZ rats, 3 intravitreal (IVT) injections of THR‐687 (75 µg/eye) or vehicle were given with a weekly interval. Four weeks after diabetes onset vascular leakage, retinal inflammation and gliosis were analyzed by means of respectively FITC‐BSA perfusion, CD11b and vimentin staining. THR‐687 was investigated in the cynomolgus CNV model, by administering 3 IVT injections of THR‐687 (4.5 mg/eye, 2.25 mg/eye or 0.45 mg/eye) or vehicle with a weekly interval. Three weeks after laser induction the anti‐fibrotic and anti‐inflammatory potential of THR‐687 was studied by Sirius red and CD11b staining, respectively.ResultsIVT administration of THR‐687 in diabetic rats significantly decreased retinal permeability, inflammation and gliosis as compared to vehicle‐treated controls. In the cynomolgus CNV model, THR‐687 exhibited a dose‐dependent inhibition of collagen deposition in the laser spots, whereas only a trend towards decreased inflammation levels could be discerned with the highest dose level 3 weeks post‐laser.ConclusionTHR‐687 potently antagonizes integrins implicated in vascular leakage, inflammation, gliosis, angiogenesis and fibrosis as demonstrated in the diabetic STZ rat and cynomolgus CNV models. Given its multifaceted mode of action and broad therapeutic potential, THR‐687 is a promising drug candidate for the treatment of vision‐threatening retinal pathologies such as DR and wet AMD.

P2RY12 expression at different time‐points in a mouse model of experimental glaucoma

AbstractPurposeDown‐regulation of P2RY12 after injury constitutes a sensitive marker for the transition from resting to activate microglia. P2RY12 is expressed by microglia but not by monocytes, infiltrating macrophages or dendritic cells, thus can used to identify resident microglia. Thus, the aims of the study is to determine the P2RY12 expression on retinal Iba‐1+ cells after unilateral laser‐induced ocular hypertension (OHT) in OHT‐eyes and their contralateral eyes, at different time points (1, 3, 5, 8 and 15 days) and in the different retinal layers such as outer segments (OS), outer plexiform layer (OPL), inner plexiform layer (IPL) and the complex nerve fiber layer‐ganglion cell layer (NFL‐GCL)), after unilateral laser‐induced ocular hypertension (ULOHT) in OHT‐eyes and their contralateral eyes.MethodsAlbino Swiss mice were divided into two groups, naïve and lasered. In this last group OHT, eyes and their contralateral eyes were studied. Retinal whole‐mounts were double‐immunostained with Iba1 and P2RY12 antibodies.ResultsIn naïve eyes, Iba‐1+ cells expressed P2RY12, with the exception of perivascular microglia and dendritic‐like Iba‐1+ cells in all retinal layers analyzed. In OHT eyes, at 24 h and 15 d after laser induction, most Iba‐1+ cells showed high P2RY12 expression in the OS, OPL, IPL and NFL‐GCL, except some rounded cells in the OS and NFL‐GCL and very few ramified cells in the IPL and NFL‐GCL. At intermediate times (3 d and 5 d), P2RY12 expression was dramatically lower than at 1d in all retinal layers. Expression increased weakly at 8 d, reaching values similar to those in naïve eyes at 15 d. In contralateral eyes, as in naïve ones, Iba‐1+ cells were intensely labelled with anti‐P2RY12 in all retinal layers at all‐time points analyzed.ConclusionMost of Iba‐1+ cells in the OHT eyes and contralateral eyes at the different time‐points were microglia, as demonstrated by their P2RY12 expression. P2RY12 expression is reduced after microglial activation indicating that 3 d and 5 d were the point‐times in which the microglial activation was maximal.AcknowledgementThis work was supported by Ophthalmological Network OFTARED (RD12‐0034/0002 and RD12/0034/0014. Prevención, Detección Precoz y Tratamiento de la Patología Ocular Prevalente Degenerativa y Crónica), the Institute of Health of Carlos III of the Spanish Ministry of Economy; PN I+D+i 2008‐2011; ISCIII, General Subdirection of Networks and Cooperative Research Centers; by the FEDER European program. Grants to J.A. Fernández‐Albarral are currently supported by a Predoctoral Fellowship (FPU) from the Spanish Ministry of Science, Innovation and University.

Laser-induced noble metal nanoparticle-graphene composites enabled flexible biosensor for pathogen detection

Noble metal nanoparticle-3D graphene hybrid nanocomposites possess the advantage of nanoparticles and graphene, which have attracted extensive interest. Here we developed a one-step laser induction method to prepare various noble metal nanoparticle-3D graphene nanocomposites. The nanocomposites were converted from polyimide film coated with the corresponding metal precursor-chitosan hydrogel ink. These nanoparticles including gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and platinum nanoparticles (PtNPs), were evenly distributed on the surface of porous 3D graphene. Furthermore, we prepared an AuNPs-3D graphene interdigitated array electrode using the one-step laser induction method, which was used to fabricate a flexible impedimetric immunosensor for the detection of Escherichia coli O157:H7. The immunosensor shows excellent performance including low detection limit, high selectivity, and great flexibility.

Study on the nucleation mechanism of hard particles in high boron and high carbon alloy by laser-induced arc welding

It is an effort to improve the phenomenon of thick boron-carbon compound forming, during the process of arc surfacing of high boron and high carbon alloy. This paper deals with the refinement of hard particles, in order to improve the microstructure of the surfacing layer. The comparison of microstructure and hard particles composition between laser arc composite surfacing layer and arc surfacing layer confirmed that hard particles of both are (Fe, Cr)7(B, C)3 and (Fe, Cr)2B. Also, the results show that in the cross section of the arc surfacing layer, the hard particles are in the shape of long strips, hexagonal and regular quadrangular blocks. But the size of hard particles decreases and follows a uniform distribution under laser induction. The wear resistance of laser arc composite surfacing layer is obviously improved. This may be due to that thick hard particles were broken into smaller units by pulsed laser stirring molten pool, thus providing more nucleating particles for the formation of hard particles. At the same time, the thick hard particles were melt down by high energy laser beam, which improves the temperature gradient and forces hard particles to grow uniformly.

Laser‐Induced Graphene Composites for Printed, Stretchable, and Wearable Electronics

AbstractGraphene‐based composites have received attention as part of the drive towards next‐generation electronic and energy‐storage technologies. However, current graphene synthesis methods are limited by complex, time‐consuming, toxic, costly, and/or often low‐yield procedures. The synthesis of a novel stretchable graphene‐polyurethane‐poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate ink aimed at printing wearable electronics is reported. The procedure is based on low‐cost high‐yield production of high‐performance graphene ink produced by laser induction of polyimide film followed by harvesting the graphene. Screen printing is used to fabricate flexible and intrinsically stretchable micro‐supercapacitors (S‐MSCs) printed on different substrates. The resulting graphene‐based printed S‐MSCs display a remarkably high capacitive performance and attractive mechanical resiliency. High specific areal capacitance, above 23 mF cm−2, is achieved, which is the highest areal capacitance reported for highly stretchable, printed graphene supercapacitors. A repeated (200 cycles) stretchability beyond 100% is obtained while maintaining more than 85% of the S‐MSCs' original capacitance. This unique and highly scalable graphene ink synthesis method holds considerable promise for application in low‐cost graphene‐based chemical formulation, especially in the field of printed and wearable electronics toward multifunctional, energy‐storage systems capable of withstanding severe mechanical deformation while maintaining their optimal electrochemical performance.

Elemental segregation in an AlCoCrFeNi high-entropy alloy – A comparison between selective laser melting and induction melting

Additive manufacturing of a high-entropy alloy, AlCoCrFeNi, was studied with selective laser melting from gas atomized powder. A wide process parameter window in the SLM process was investigated but it was impossible to produce crack-free samples, attributed to stresses that originate during the building processes. The microstructure and elemental segregation in the SLM samples were compared with induction-melted AlCoCrFeNi. The induction-melted sample crystallizes in randomly oriented large grains (several hundred microns). Dendritic and inter-dendritic areas with slightly different chemical composition can be observed. Within these areas a spinodal decomposition occurs with a separation into FeCr- and NiAl-rich domains. Further spinodal decomposition within the FeCr-rich regions into Cr- and Fe-rich domains was observed by atom probe tomography.In contrast, the SLM-samples crystallizes in much smaller grains (less than 20 μm) with a dendrite-like substructure. These dendrite-like features exhibit distinct chemical fluctuations on the nm-scale. During annealing more pronounced chemical fluctuations and the formation of Cr-rich and Cr-poor regions can be observed. The difference in microstructure and spinodal decomposition between the induction-melted and SLM samples is attributed to the significantly higher cooling rate for SLM. This study shows that, by using different synthesis pathways, it is possible to modify the microstructure and segregation of element within alloys. This can be used to tune the materials properties, if the cracking behavior is handled e.g. by change of alloy composition to minimize phase transformations or use of a heating stage.

Preclinical SPECT Imaging of Choroidal Neovascularization in Mice Using Integrin-Binding [99mTc]IDA-D-[c(RGDfK)]2.

Integrin ɑvβ3, an adhesion molecule overexpressed in neovascular endothelial cells, is involved in ocular angiogenesis. Integrin ɑvβ3-binding arginine-glycine-aspartic acid (RGD) peptide has been used to target and visualize new vessels. We explored the use of integrin ɑvβ3-targeted RGD peptide ([99mTc]IDA-D-[c(RGDfK)]2) for in vivo molecular imaging of choroidal neovascularization (CNV). To induce CNV in animals, the right eyes of C57BL/6 mice were treated with retinal argon laser photocoagulation. CNV formation was confirmed on immunohistopathological examination of retinal and choroidal tissues. To explore the association of integrin with angiogenesis, integrin mRNA expression in the retinal and choroidal tissues was measured using real-time reverse transcriptase-polymerase chain reaction. For in vivo imaging, mice were intravenously injected with [99mTc]IDA-D-[c(RGDfK)]2 and single-photon emission computed tomography (SPECT) images of [99mTc]IDA-D-[c(RGDfK)]2 were obtained before laser induction (baseline) and at 1, 3, 7, and 14days post-induction. CNV-induced regional alterations were measured using radiotracer uptake count. Immunohistopathological examination revealed that CNV lesions showed intense fluorescein isothiocyanate (FITC)-D-[c(RGDfK)]2 immunofluorescence, in contrast to the normal retina and choroid. Retinal integrin mRNA expression peaked at day 1 following CNV induction. On SPECT images using [99mTc]IDA-D-[c(RGDfK)]2, the radio-uptake count in eyes with CNV was significantly higher than in normal controls on days 1-7 (all p < 0.05), with a peak at day 3 representing the highest angiogenic activity. Our preclinical data demonstrated that [99mTc]IDA-D-[c(RGDfK)]2 can detect CNV and its associated angiogenesis in an animal model of CNV. SPECT imaging using an integrin ɑvβ3-targeted RGD peptide radiotracer may be a useful tool for in vivo functional molecular imaging of CNV.

Detection of Neurotransmitters by Three-Dimensional Laser-Scribed Graphene Grass Electrodes.

Carbon nanomaterials possess superb properties and have contributed considerably to the advancement of integrated point-of-care chemical and biological sensing devices. Graphene has been widely researched as a signal transducing and sensing material. Here, a grass-like laser-scribed graphene (LSG) was synthesized by direct laser induction on common polyimide plastics. The resulting LSG grass was employed as a disposable electrochemical sensor for the detection of three neurotransmitters, dopamine (DA), epinephrine (EP), and norepinephrine (NE), and in the presence of uric acid and ascorbic acid as potential interferants, using differential pulse voltammetry and cyclic voltammetry. The LSG grass sensor achieved sensitivities of 0.243, 0.067, and 0.110 μA μM-1 for DA, EP, and NE, respectively, whereas the limits of detection were 0.43, 1.1, and 1.3 μM, respectively. The selectivity of LSG grass was excellent for competing biomarkers with high structural similarity (EP vs NE and EP vs DA). The exceptional performance of LSG grass for DA, EP, and NE detection holds a promising future for carbon nanomaterial sensors with unique surface morphologies.

Microstructure formation of Ti-6Al-4 V in synchronous induction assisted laser deposition

Laser deposition (LD) is a useful repair technique and in-situ microstructure control is significant. However, the ability of in-situ microstructural control is inevitably limited in LD. Introducing induction heating into laser deposition is a potential solution for this challenging issue. In this research, the synchronous induction assisted laser deposition of Ti-6Al-4 V alloy were conducted and a thermal analysis model was established to investigate the influences of laser and induction energy on the morphology and size of the grains, the phase, and the Vickers hardness. Results showed that both of the thickness of equiaxed grain zone and the width of columnar grains increased with increasing laser energy and induction energy. The fraction of α phase increases with increasing induction energy due to sharply reduction of cooling rate during the cooling period caused by the post-heating, while the fraction of martensite increased with increasing laser energy. The “800 W-600A” and “1000 W-300A” samples have similar β grain morphology and size but consist of different phase, which is very distinctive from usual laser deposition process. This novel discovery indicates a great potential of microstructure control, the grains and the phase can be controlled separately by adjusting the laser parameters and induction parameters.

Laser-Induced Graphene from Wood Impregnated with Metal Salts and Use in Electrocatalysis

The hybridization of graphene with other inorganic nanostructures has endowed graphene with enhanced and varied functionalities. Here we demonstrate a facile and improved approach to convert biodegradable cedar wood into graphene embedded with various metal nanocrystals (cedar-LIG-M, LIG is laser-induced graphene, M = Cu, Co, Ni, Fe, NiFe) by sonication-assisted soaking and one-step CO2 laser scribing. Organic biomass was transformed to hierarchical porous graphene via laser induction, whereas metal salts were reduced to elemental metals simultaneously by the carbothermal reaction and reducing atmosphere generated during the lignocellulose decomposition. The as-prepared cedar-LIG-M possesses an ordered porous structure, good conductivity, unique ferromagnetic behavior and excellent electrochemical catalytic performance. As a demonstration, the cedar-LIG-NiFe electrode has a low overpotential of 296 mV at a current density of 10 mA cm–2 for oxygen evolution reactions. The performance of the electrode conti...

Bilateral early activation of retinal microglial cells in a mouse model of unilateral laser-induced experimental ocular hypertension

The immune system plays an important role in glaucomatous neurodegeneration. Retinal microglial reactivation associated with ganglion cell loss could reportedly contribute to the glaucoma progression. Recently we have described signs of microglia activation both in contralateral and ocular hypertension (OHT) eyes involving all retinal layers 15 days after OHT laser induction in mice. However, no works available have analyzed the microglial activation at earliest time points after OHT induction (24 h) in this experimental model. Thus, we seek to describe and quantify signs of microglia activation and differences depending on the retinal layer, 24 h after unilateral laser-induced OHT. Two groups of adult Swiss mice were used: age-matched control (naïve) and lasered. In the lasered animals, OHT eyes as well as contralateral eyes were analyzed. Retinal whole-mounts were immunostained with antibodies against Iba-1 and MHC-II. We quantified the number of microglial cells in the photoreceptor layer (OS), outer plexiform layer (OPL), and inner plexiform layer (IPL); the number of microglial vertical processes connecting the OPL and OS; the area of the retina occupied by Iba-1+ cells (Iba1-RA) in the nerve fiber layer-ganglion cell layer (NFL-GCL), the total arbor area of microglial cells in the OPL and IPL and; Iba-1+ cell body area in the OPL, IPL and NFL-GCL. In contralateral and OHT eyes the morphological features of Iba-1+ cell activation were: migration, enlargement of the cell body, higher degree of branching and reorientation of the processes, radial disposition of the soma and processes toward adjacent microglial plexuses, and presence of amoeboid cells acting as macrophages. These signs were more pronounced in OHT eyes. Most of Iba-1+ cells did not express MHC-II; rather, only dendritic and rounded cells expressed it. In comparison with naïve eyes, in OHT eyes and contralateral eyes no significant differences were found in the microglial cell number; but there was a significant increase in Iba1-RA. The total arbor area of microglial cells was significantly decreased in: i) OHT eyes with respect contralateral eyes and naïve-eyes in IPL; ii) OHT eyes with respect to naïve eyes in OPL. The number of microglial vertical processes connecting the OPL and OS were significantly increased in contralateral eyes compared with naïve-eyes and OHT eyes. In OPL, IPL and NFL-GCL, the cell body area of Iba-1+ cells was significantly greater in OHT eyes than in naïve and contralateral eyes, and greater in contralateral eyes than in naïve eyes. A non-proliferative microglial reactivation was detected both in contralateral eyes and in OHT eyes in an early time after unilateral laser-induced OHT (24 h). This fast microglial activation, which involves the contralateral eye, could be mediated by the immune system.