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Silicon and Germanium oxide (SiO x and GeO x ) nanostructures are promising materials for energy storage applications due to their potentially high energy density, large lithiation capacity (~10X carbon), low toxicity, low cost, and high thermal stability. This work reports a unique approach to achieving controlled synthesis of SiO x and GeO x nanostructures via photonic curing. Unlike conventional methods like rapid thermal annealing, quenching during pulsed photonic curing occurs rapidly (sub-millisecond), allowing the trapping of metastable states to form unique phases and nanostructures. We explored the possible underlying mechanism of photonic curing by incorporating laws of photophysics, photochemistry, and simulated temperature profile of thin film. The results show that photonic curing of spray coated 0.1 M molarity Si and Ge Acetyl Acetate precursor solution, at total fluence 80 J cm -2 can yield GeO x and SiO x nanostructures. The as-synthesized nanostructures are ester functionalized due to photoinitiated chemical reactions in thin film during photonic curing. Results also showed that nanoparticle size changes from ~48 nm to ~11 nm if overall fluence is increased by increasing the number of pulses. These results are an important contribution towards large-scale synthesis of the Ge and Si oxide nanostructured materials which is necessary for next-generation energy storage devices., (© 2024 The Authors. ChemistryOpen published by Wiley-VCH GmbH.)

Biophysical insults that either reduce barrier function (COVID-19, smoke inhalation, aspiration, and inflammation) or increase mechanical stress (surfactant dysfunction) make the lung more susceptible to atelectrauma. We investigate the susceptibility and time-dependent disruption of barrier function associated with pulmonary atelectrauma of epithelial cells that occurs in acute respiratory distress syndrome (ARDS) and ventilator-induced lung injury (VILI). This in vitro study was performed using Electric Cell-substrate Impedance Sensing (ECIS) as a noninvasive evaluating technique for repetitive stress stimulus/response on monolayers of the human lung epithelial cell line NCI-H441. Atelectrauma was mimicked through recruitment/derecruitment (RD) of a semi-infinite air bubble to the fluid-occluded micro-channel. We show that a confluent monolayer with a high level of barrier function is nearly impervious to atelectrauma for hundreds of RD events. Nevertheless, barrier function is eventually diminished, and after a critical number of RD insults, the monolayer disintegrates exponentially. Confluent layers with lower initial barrier function are less resilient. These results indicate that the first line of defense from atelectrauma resides with intercellular binding. After disruption, the epithelial layer community protection is diminished and atelectrauma ensues. ECIS may provide a platform for identifying damaging stimuli, ventilation scenarios, or pharmaceuticals that can reduce susceptibility or enhance barrier-function recovery.

Staphylococcus aureus (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) bacteria represent major infectious threats in the hospital environment due to their wide distribution, opportunistic behavior, and increasing antibiotic resistance. This study reports on the deposition of polyvinylpyrrolidone/antibiotic/isoflavonoid thin films by the matrix-assisted pulsed laser evaporation (MAPLE) method as anti-adhesion barrier coatings, on biomedical surfaces for improved resistance to microbial colonization. The thin films were characterized by Fourier transform infrared spectroscopy, infrared microscopy, and scanning electron microscopy. In vitro biological assay tests were performed to evaluate the influence of the thin films on the development of biofilms formed by Gram-positive and Gram-negative bacterial strains. In vitro biocompatibility tests were assessed on human endothelial cells examined for up to five days of incubation, via qualitative and quantitative methods. The results of this study revealed that the laser-fabricated coatings are biocompatible and resistant to microbial colonization and biofilm formation, making them successful candidates for biomedical devices and contact surfaces that would otherwise be amenable to contact transmission.

We describe the instantaneous fabrication of a highly porous three-dimensional (3D) nanostructured manganese oxides-reduced graphitic oxide (MnO x -rGO) electrode by using a pulse-photonic processing technique. Such nanostructures facilitate the movement of ions/electrons and offer an extremely high surface area for the electrode/electrolyte interaction. The electrochemical performance was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) with 1 M KOH as the electrolyte. The as-prepared thin film electrode exhibits excellent electrochemical performance and an ultra-long lifetime by retaining 90% of the initial capacitance even after 100 000 GCD cycles at constant areal current density of 0.4 mA cm -2 . We attribute this excellent lifetime performance to the conductive reduced graphitic oxide, synergistic effects of carbon composite and the metal oxides, and the unique porous nanostructure. Such highly porous morphology also enhances the structural stability of the electrode by buffering the volume changes during the redox processes., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Matrix-assisted pulsed laser evaporation (MAPLE) has many benefits over conventional methods (e.g., dip-coating, spin coating, and Langmuir-Blodgett dip-coating) for manufacturing coatings containing pharmacologic agents on medical devices. In particular, the thickness of the coating that is applied to the surface of the medical device can be tightly controlled. In this study, MAPLE was used to deposit rapamycin-polyvinylpyrrolidone (rapamycin-PVP) thin films onto silicon and borosilicate optical glass substrates. Alamar Blue and PicoGreen studies were used to measure the metabolic health and DNA content of L929 mouse fibroblasts as measures of viability and proliferation, respectively. The cells on the MAPLE-deposited rapamycin-PVP surfaces exhibited 70.6% viability and 53.7% proliferation compared to a borosilicate glass control. These data indicate that the antiproliferative properties of rapamycin were maintained after MAPLE deposition., (Copyright: © 2020 Cristescu, et al.)

Three-dimensional (3D) printing has been emerging as a new technology for scaffold fabrication to overcome the problems associated with the undesirable microstructure associated with the use of traditional methods. Solvent-based extrusion (SBE) 3D printing is a popular 3D printing method, which enables incorporation of cells during the scaffold printing process. The scaffold can be customized by optimizing the scaffold structure, biomaterial, and cells to mimic the properties of natural tissue. However, several technical challenges prevent SBE 3D printing from translation to clinical use, such as the properties of current biomaterials, the difficulties associated with simultaneous control of multiple biomaterials and cells, and the scaffold-to-scaffold variability of current 3D printed scaffolds. In this review paper, a summary of SBE 3D printing for tissue engineering (TE) is provided. The influences of parameters such as ink biomaterials, ink rheological behavior, cross-linking mechanisms, and printing parameters on scaffold fabrication are considered. The printed scaffold structure, mechanical properties, degradation, and biocompatibility of the scaffolds are summarized. It is believed that a better understanding of the scaffold fabrication process and assessment methods can improve the functionality of SBE-manufactured 3D printed scaffolds., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020, Whioce Publishing Pte. Ltd.)

In chemotherapy-treated breast cancer, wild-type p53 preferentially induces senescence over apoptosis, resulting in a persisting cell population constituting residual disease that drives relapse and poor patient survival via the senescence-associated secretory phenotype. Understanding the properties of tumor cells that allow survival after chemotherapy treatment is paramount. Using time-lapse and confocal microscopy to observe interactions of cells in treated tumors, we show here that chemotherapy-induced senescent cells frequently engulf both neighboring senescent or nonsenescent tumor cells at a remarkable frequency. Engulfed cells are processed through the lysosome and broken down, and cells that have engulfed others obtain a survival advantage. Gene expression analysis showed a marked up-regulation of conserved macrophage-like program of engulfment in chemotherapy-induced senescent cell lines and tumors. Our data suggest compelling explanations for how senescent cells persist in dormancy, how they manage the metabolically expensive process of cytokine production that drives relapse in those tumors that respond the worst, and a function for their expanded lysosomal compartment., (© 2019 Tonnessen-Murray et al.)

Triple negative breast cancers (TNBCs) have high recurrence and metastasis rates. Acquisition of a mesenchymal morphology and phenotype in addition to driving migration is a consequential process that promotes metastasis. Although some kinases are known to regulate a mesenchymal phenotype, the role for a substantial portion of the human kinome remains uncharacterized. Here we evaluated the Published Kinase Inhibitor Set (PKIS) and screened a panel of TNBC cell lines to evaluate the compounds' effects on a mesenchymal phenotype. Our screen identified 36 hits representative of twelve kinase inhibitor chemotypes based on reversal of the mesenchymal cell morphology, which was then prioritized to twelve compounds based on gene expression and migratory behavior analyses. We selected the most active compound and confirmed mesenchymal reversal on transcript and protein levels with qRT-PCR and Western Blot. Finally, we utilized a kinase array to identify candidate kinases responsible for the EMT reversal. This investigation shows the novel application to identify previously unrecognized kinase pathways and targets in acquisition of a mesenchymal TNBC phenotype that warrant further investigation. Future studies will examine specific roles of the kinases in mechanisms responsible for acquisition of the mesenchymal and/or migratory phenotype.

Transdermal delivery of amphotericin B, a pharmacological agent with activity against fungi and parasitic protozoa, is a challenge since amphotericin B exhibits poor solubility in aqueous solutions at physiologic pH values. In this study, we have used a laser-based printing approach known as matrix-assisted pulsed laser evaporation to print amphotericin B on the surfaces of polyglycolic acid microneedles that were prepared using a combination of injection molding and drawing lithography. In a modified agar disk diffusion assay, the amphotericin B-loaded microneedles showed concentration-dependent activity against the yeast Candida albicans . The results of this study suggest that matrix-assisted pulsed laser evaporation may be used to print amphotericin B and other drugs that have complex solubility issues on the surfaces of microneedles., Competing Interests: No conflict of interest was reported by the authors. We would like to acknowledge C Mooney (NCSU Analytical Instrumentation Facility) for his aid with electron microscopy, B Andersen for her aid with Fourier transform infared spectrosocpy (NCSU College of Textiles), P Strader (NCSU Analytical Instrumentation Facility) for his aid with nanoindentation, the US National Institutes of Health (Award # 1R21AI117748- 01A1), the US National Science Foundation (Award CMMI 1258536), and the US Office of Naval Research (Award # N00014-15-1-2323). This work was also supported by the National Program PN 4N/2016(1647- LAPLAS IV and a grant of Ministry of Research and Innovation, CNCS - UEFISCDI, Project Number PN- III-P4-ID-PCE-2016-0884, within PNCDI III., (Copyright: © 2017 Sachan, et al.)

Laser-induced forward transfer has been a promising orifice-free bioprinting technique for the direct writing of three-dimensional cellular constructs from cell-laden bioinks. In order to optimize the printing performance, the effects of living cells on the bioink printability must be carefully investigated in terms of the ability to generate well-defined jets during the jet/droplet formation process as well as well-defined printed droplets on a receiving substrate during the jet/droplet deposition process. In this study, a time-resolved imaging approach has been implemented to study the jet/droplet formation and deposition processes when printing cell-free and cell-laden bioinks under different laser fluences. It is found that the jetting behavior changes from no material transferring to well-defined jetting with or without an initial bulgy shape to jetting with a bulgy shape/pluming/splashing as the laser fluence increases. Under desirable well-defined jetting, two impingement-based deposition and printing types are identified: droplet-impingement printing and jet-impingement printing with multiple breakups. Compared with cell-free bioink printing, the transfer threshold of the cell-laden bioink is higher while the jet velocity, jet breakup length, and printed droplet size are lower, shorter, and smaller, respectively. The addition of living cells transforms the printing type from jet-impingement printing with multiple breakups to droplet-impingement printing. During the printing of cell-laden bioinks, two non-ideal jetting behaviors, a non-straight jet with a non-straight trajectory and a straight jet with a non-straight trajectory, are identified mainly due to the local nonuniformity and nonhomogeneity of cell-laden bioinks.

Laser direct-write (LDW) bioprinting methods offer a diverse set of tools to design experiments, fabricate tissue constructs and to cellular microenvironments all in a CAD/CAM manner. To date, we have just scratched the surface of the system's potential and for LDW to be utilized to its fullest, there are many distinct hardware and software components that must be integrated and communicate seamlessly. In this perspective article, we detail the development of novel graphical user interface (GUI) software to improve LDW capability and functionality. The main modules in the control software correspond to cell transfer, microbead fabrication, and micromachining. The modules make the control of each of these features, and the management of printing programs that utilize one or more features, to be facile. The software also addresses problems related to construct scale-up, print speed, experimental conditions, and management of sensor data. The control software and possibilities for integrated sensor data are presented., Competing Interests: No conflict of interest was reported by the authors., (Copyright: © 2017 Sklare, et al.)

Increasing biomedical applications of iron oxide nanoparticles (IONPs) in academic and commercial settings have alarmed the scientific community about the safety and assessment of toxicity profiles of IONPs. The great amount of diversity found in the cytotoxic measurements of IONPs points toward the necessity of careful characterization and quantification of IONPs. The present document discusses the major developments related to in vitro and in vivo toxicity assessment of IONPs and its relationship with the physicochemical parameters of IONPs. Major discussion is included on the current spectrophotometric and imaging based techniques used for quantifying, and studying the clearance and biodistribution of IONPs. Several invasive and non-invasive quantification techniques along with the pitfalls are discussed in detail. Finally, critical guidelines are provided to optimize the design of IONPs to minimize the toxicity.

The ability to precisely pattern embryonic stem (ES) cells in vitro into predefined arrays/geometries may allow for the recreation of a stem cell niche for better understanding of how cellular microenvironmental factors govern stem cell maintenance and differentiation. In this study, a new gelatin-based laser direct-write (LDW) technique was utilized to deposit mouse ES cells into defined arrays of spots, while maintaining stem cell pluripotency. Results obtained from these studies showed that ES cells were successfully printed into specific patterns and remained viable. Furthermore, ES cells retained the expression of Oct4 in nuclei after LDW, indicating that the laser energy did not affect their maintenance of an undifferentiated state. The differentiation potential of mouse ES cells after LDW was confirmed by their ability to form embryoid bodies (EBs) and to spontaneously become cell lineages representing all three germ layers, revealed by the expression of marker proteins of nestin (ectoderm), Myf-5 (mesoderm) and PDX-1 (endoderm), after 7 days of cultivation. Gelatin-based LDW provides a new avenue for stem cell patterning, with precision and control of the cellular microenvironment., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Three-dimensional microstructured medical devices, including microneedles and tissue engineering scaffolds, were fabricated by two photon induced polymerization of Ormocer organic-inorganic hybrid materials. Femtosecond laser pulses from a titanium:sapphire laser were used to break chemical bonds on Irgacure 369 photoinitiator within a small focal volume. The radicalized starter molecules reacted with Ormocer US-S4 monomers to create radicalized polymolecules. The desired structures are fabricated by moving the laser focus in three dimensions using a galvano-scanner and a micropositioning system. Ormocer surfaces fabricated using two photon induced polymerization demonstrated acceptable cell viability and cell growth profiles against B35 neuroblast-like cells and HT1080 epithelial-like cells. Lego-like interlocking tissue engineering scaffolds and microneedle arrays with unique geometries were created using two photon induced polymerization. These results suggest that two photon induced polymerization is able to create medical microdevices with a larger range of sizes, shapes, and materials than chemical isotropic etching, injection molding, reactive ion etching, surface micromachining, bulk micromachining, polysilicon micromolding, lithography-electroforming-replication, or other conventional microfabrication techniques.

We have generated mesoscopic patterns of viable Escherichia coli on Si(1 1 1), glass, and nutrient agar plates by using a novel laser-based transfer process termed matrix assisted pulsed laser evaporation direct write (MAPLE DW). We observe no alterations to the E. coli induced by the laser-material interaction or the shear forces during the transfer. Transferred E. coli patterns were observed by optical and electron microscopes, and cell viability was shown through green fluorescent protein (GFP) expression and cell culturing experiments. The transfer mechanism for our approach appears remarkably gentle and suggests that active biomaterials such as proteins, DNA and antibodies could be serially deposited adjacent to viable cells. Furthermore, this technique is a direct write technology and therefore does not involve the use of masks, etching, or other lithographic tools.

In a direct-write approach, micrometer-scale structures are built directly without the use of masks, allowing rapid prototyping. Direct-write approaches are enabling faster, cheaper manufacture of electronic components and are also used for tissue engineering and array-based biosensors. In his Perspective, Chrisey provides a short overview of current research in the area of direct-write technologies, focusing on the materials science aspects.