ORCID Profile
0000-0002-7752-5417
Current Organisation
Monash University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Nanoscale Characterisation | Materials Engineering not elsewhere classified | Materials Engineering | Photonics and Electro-Optical Engineering (excl. Communications) | Biochemistry and Cell Biology | Interdisciplinary Engineering not elsewhere classified | Analytical Spectrometry | Chemical Characterisation of Materials | Heritage and Cultural Conservation | Medical Biotechnology not elsewhere classified | Biochemistry and Cell Biology not elsewhere classified | Nanotechnology | Manufacturing Processes and Technologies (excl. Textiles) | Performing Arts and Creative Writing | Interdisciplinary Engineering | Composite and Hybrid Materials | Biomedical Engineering not elsewhere classified | Musicology and Ethnomusicology | Condensed Matter Imaging |
ANZSRC Socio-Economic Objective (SEO)
Manufacturing not elsewhere classified | Expanding Knowledge in Technology | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Conserving Collections and Movable Cultural Heritage | Music | Expanding Knowledge in the Medical and Health Sciences | Expanding Knowledge in the Chemical Sciences | Scientific Instruments | Expanding Knowledge in the Biological Sciences | Health Protection and/or Disaster Response
Related Links
Publications
Optimization based geometric modeling of nano/micro scale ion milling of organic materials for multidimensional bioimaging
Publisher: ASME International
Date: 08-2010
DOI: 10.1115/1.4001851
Abstract: Focused ion beam (FIB) instruments have recently started to be seen in applications to organic materials such as polymers and biological s les. FIB provides a novel tool for sectioning biological s les for electron microscope based imaging or microfabrication with environment friendly materials. The modeling of nano/micro scale geometry accurately sculptured by FIB milling is crucial for generating the milling plan and process control, and for computer simulation based prediction and visualization of the milled geometry. However, modeling of the milled geometry on compound materials, especially for high aspect ratio feature, is still difficult due to the complexity of target material, as well as multiple physical and chemical interactions involved. In this study, a comprehensive model of ion milling with organic targets is presented to address the challenges in using a simulation based approach. At each discrete point of the milled front, the depth is the dynamic result of aggregate interactions from neighboring areas, including physical sputtering and chemical reactions. Instead of determining the exact interactions, the parameters of the proposed model are estimated by studying a number of preliminary milling results followed by a nonlinear optimization model. This platform has been validated by milling different features on water ice in a cryogenic environment, and the simulation and experiment results show great consistency. With the proliferation of nanotechnology in biomedical and biomaterial domains, the proposed approach is expected to be a flexible tool for various applications involving novel and heterogeneous biological targets.
In situprobing the interior of single bacterial cells at nanometer scale
Publisher: IOP Publishing
Date: 26-09-2014
DOI: 10.1088/0957-4484/25/41/415101
Abstract: We report a novel approach to probe the interior of single bacterial cells at nanometre resolution by combining focused ion beam (FIB) and atomic force microscopy (AFM). After removing layers of pre-defined thickness in the order of 100 nm on the target bacterial cells with FIB milling, AFM of different modes can be employed to probe the cellular interior under both ambient and aqueous environments. Our initial investigations focused on the surface topology induced by FIB milling and the hydration effects on AFM measurements, followed by assessment of the s le protocols. With fine-tuning of the process parameters, in situ AFM probing beneath the bacterial cell wall was achieved for the first time. We further demonstrate the proposed method by performing a spatial mapping of intracellular elasticity and chemistry of the multi-drug resistant strain Klebsiella pneumoniae cells prior to and after it was exposed to the 'last-line' antibiotic polymyxin B. Our results revealed increased stiffness occurring in both surface and interior regions of the treated cells, suggesting loss of integrity of the outer membrane from polymyxin treatments. In addition, the hydrophobicity measurement using a functionalized AFM tip was able to highlight the evident hydrophobic portion of the cell such as the regions containing cell membrane. We expect that the proposed FIB-AFM platform will help in gaining deeper insights of bacteria-drug interactions to develop potential strategies for combating multi-drug resistance.
Large-scale process optimization for focused ion beam 3-D nanofabrication
Publisher: Springer Science and Business Media LLC
Date: 25-08-2013
Nanoscale coating on tip geometry by cryogenic focused ion beam deposition
Publisher: Elsevier BV
Date: 10-2021
Free-Standing Polymer–Nanoparticle Superlattice Sheets Self-Assembled at the Air–Liquid Interface
Publisher: American Chemical Society (ACS)
Date: 03-10-2011
DOI: 10.1021/CG200867A
Near-Atomic Three-Dimensional Mapping for Site-Specific Chemistry of ‘Superbugs’
Publisher: American Chemical Society (ACS)
Date: 14-10-2016
Understanding the Effects of Graphene Coating on the Electrostatic Field at the Tip of an Atom Probe Tomography Specimen
Publisher: Oxford University Press (OUP)
Date: 08-2021
DOI: 10.1017/S1431927621012356
Abstract: As a three-dimensional characterization method, atom probe tomography can provide key information that other methods cannot offer. Conductive coatings have proved to be an effective way for biological s les, and nonconductive s les in general, to be analyzed using voltage-pulsed atom probe tomography. In this study, we analyzed the effects of graphene coating on an electrically conductive material and were able to confirm the detection of carbon atoms. We compare quantitative electrostatic field metrics for a single-coated and a multi-coated specimen and measure both a reduced voltage after graphene coating and lowered charge-state ratios for different ion species, suggesting a lowered evaporation field related to the graphene coating. This information will be instructive for future studies on graphene-coated, nonconductive biological specimens.
Synergy of the Polymyxin-Chloramphenicol Combination against New Delhi Metallo-β-Lactamase-Producing Klebsiella pneumoniae Is Predominately Driven by Chloramphenicol
Publisher: American Chemical Society (ACS)
Date: 09-04-2021
Precise drop dispensation on superhydrophobic surfaces using acoustic nebulization
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SM00016H
Synchrotron-Based X-Ray Fluorescence Microscopy Reveals Accumulation of Polymyxins in Single Human Alveolar Epithelial Cells
Publisher: American Society for Microbiology
Date: 19-04-2021
DOI: 10.1128/AAC.02314-20
Abstract: Intravenous administration of the last-line polymyxins results in poor drug exposure in the lungs and potential nephrotoxicity, whereas inhalation therapy offers better pharmacokinetics harmacodynamics for pulmonary infections by delivering the antibiotic directly to the infection site. However, polymyxin inhalation therapy has not been optimized, and adverse effects can occur.
Electron caustic lithography
Publisher: AIP Publishing
Date: 06-2012
DOI: 10.1063/1.4730139
Abstract: A maskless method of electron beam lithography is described which uses the reflection of an electron beam from an electrostatic mirror to produce caustics in the demagnified image projected onto a resist–coated wafer. By varying the electron optics, e.g. via objective lens defocus, both the morphology and dimensions of the caustic features may be controlled, producing a range of bright and tightly focused projected features. The method is illustrated for line and fold caustics and is complementary to other methods of reflective electron beam lithography.
Modelling and fabrication of thermally actuated micropores for biological sensing
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2034147
Healing Assessment of Fractured Femur by Strain Measurement using Fibre Bragg Grating Sensors
Publisher: IEEE
Date: 08-2019
Improved Enhancement Factor for SERS using Broad Ion Beam Induced Self-organized Gold Nanocones
Publisher: Springer Science and Business Media LLC
Date: 02-2019
DOI: 10.1557/ADV.2019.131
Polymyxins Bind to the Cell Surface of Unculturable Acinetobacter baumannii and Cause Unique Dependent Resistance
Publisher: Wiley
Date: 08-06-2020
Three‐dimensional nanocharacterization of porous hydrogel with ion and electron beams
Publisher: Wiley
Date: 06-08-2012
DOI: 10.1002/BIT.24612
Abstract: Porous hydrogels provide an excellent environment for cell growth and tissue regeneration, with high permeability for oxygen, nutrients, and other water-soluble metabolites through their high water-content matrix. The ability to image three-dimensional (3D) cell growth is crucial for understanding and studying various cellular activities in 3D context, particularly for designing new tissue engineering scaffold, but it is still challenging to study cell-biomaterial interfaces with high resolution imaging. We demonstrate using focused ion beam (FIB) milling, electron imaging, and associated microanalysis techniques that novel 3D characterizations can be performed effectively on cells growing inside 3D hydrogel scaffold. With FIB-tomography, the porous microstructures were revealed at nanometer resolution, and the cells grown inside. The results provide a unique 3D measurement of hydrogel porosity, as compared with those from porosimetry, and offer crucial insights into material factors affecting cell proliferation at specific regions within the scaffold. We also proved that high throughput correlative imaging of cell growth is viable through a silicon membrane based environment. The proposed approaches, together with the protocols developed, provide a unique platform for analysis of the microstructures of novel biomaterials, and for exploration of their interactions with the cells as well.
Low-Cost Silicone Imaging Casts for Zebrafish Embryos and Larvae
Publisher: Mary Ann Liebert Inc
Date: 02-2014
Abstract: Due to their size and optical clarity, zebrafish embryos have long been appreciated for their usefulness in time-lapse confocal microscopy. Current methods of mounting zebrafish embryos and larvae for imaging consist mainly of mounting in low percentage, low melting temperature agarose in a Petri dish. Whereas imaging methods have advanced greatly over the last two decades, the methods for mounting embryos have not changed significantly. In this article, we describe the development and use of 3D printed plastic molds. These molds can be used to create silicone casts and allow embryos and larvae to be mounted with a consistent and reproducible angle, and position in X, Y, and Z. These molds are made on a 3D printer and can be easily and cheaply reproduced by anyone with access to a 3D printer, making this method accessible to the entire zebrafish community. Molds can be reused to create additional casts, which can be reused after imaging. These casts are compatible with any upright microscope and can be adapted for use on an inverted microscope, taking the working distance of the objective used into account. This technique should prove to be useful to any researcher imaging zebrafish embryos.
Nature of crystalline particle assembly in ring shaped colloidal stains from concentrated dispersions
Publisher: Elsevier BV
Date: 05-2014
Significant Accumulation of Polymyxin in Single Renal Tubular Cells: A Medicinal Chemistry and Triple Correlative Microscopy Approach
Publisher: American Chemical Society (ACS)
Date: 15-01-2015
DOI: 10.1021/AC504516K
Optimization based geometric modeling of nano/micro scale ion milling of organic materials
Publisher: ASMEDC
Date: 2009
Abstract: Recently, Focused Ion Beam (FIB) instruments have begun be applied to organic materials such as polymers and biological systems. This provides a novel tool for sectioning biological s les for analysis, or microfabrication with environment friendly materials. The modeling of nano/micro scale geometry accurately sculptured by FIB milling is crucial for generating the milling plan and process control, and for computer simulation for prediction and visualization of the milled geometry. However, modeling of the ion milling process on compound materials, especially for high aspect ratio feature, is still difficult due to the complexity of target material, as well as multiple physical and chemical interactions involved. In this study, a comprehensive model of ion milling with organic targets is presented to address the challenges using a simulation based approach. This platform has also been validated by milling different features on water ice in a cryogenic environment, and the simulation and experiment results show great consistency. With the proliferation of nanotechnology to biomedical and biomaterial domains, the proposed approach is expected to be a flexible tool for various applications involving novel and heterogeneous milling targets.
Graphene-Enhanced 3D Chemical Mapping of Biological Specimens at Near-Atomic Resolution
Publisher: Wiley
Date: 20-06-2018
Weaving nanostructures with site-specific ion induced bidirectional bending
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NA00382G
Abstract: Weaving nanostructures with site-specific ion induced bidirectional bending and a typical 3D folded nanostructure in the form of a mesh.
Facile fabrication of functional 3D micro-nano architectures with focused ion beam implantation and selective chemical etching
Publisher: Elsevier BV
Date: 10-2020
Scale-like cantilever cell traps
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3RA46123H
Sputtering rate of micromilling on water ice with focused ion beam in a cryogenic environment
Publisher: American Vacuum Society
Date: 04-04-2008
DOI: 10.1116/1.2902962
Abstract: The use of focused ion beam (FIB) milling in a cryogenic environment provides an alternative to cryomicrotome for creating submicron sections of frozen hydrated s les. Although FIB milling has been widely implemented to sculpt inorganic s le sections for analysis such as transmission electron microscopy, the application of this technique to frozen biological s les has scarcely begun. The interactions of gallium ions used in FIB with water ice as the target are still not well understood, impeding the development of this technique for routine biological analysis. In this research, amorphous water ice s les are prepared by both vapor deposition and plunge freezing, and the sputtering yield is studied based on a number of process parameters, including ion energy, temperature, and ion current. Results show that sputtering of water ice by gallium ions is a compound process of nuclear sputtering and electronic sputtering. Analytical models, originally limited to astrophysics, are adopted in this study to predict the sputtering yield of water ice by FIB. The parameters for gallium ions at keV range are estimated and validated based on the experimental data. Temperature dependence of sputtering yield is also observed in the range between 83 and 123K, in which significant increase of sputtering yield occurs when the temperature approaches 123K. Sputtering yield is not significantly affected by variation of the ion current as shown by the data. Based on these results, the process parameters involved can be characterized, and feasible settings can be developed to facilitate reproducibility and ultimately the widespread implementation of FIB to biological s le preparation.
3D visualization of HIV transfer at the virological synapse between dendritic cells and T cells
Publisher: Proceedings of the National Academy of Sciences
Date: 12-07-2010
Abstract: The efficiency of HIV infection is greatly enhanced when the virus is delivered at conjugates between CD4 + T cells and virus-bearing antigen-presenting cells such as macrophages or dendritic cells via specialized structures known as virological synapses. Using ion abrasion SEM, electron tomography, and superresolution light microscopy, we have analyzed the spatial architecture of cell-cell contacts and distribution of HIV virions at virological synapses formed between mature dendritic cells and T cells. We demonstrate the striking envelopment of T cells by sheet-like membrane extensions derived from mature dendritic cells, resulting in a shielded region for formation of virological synapses. Within the synapse, filopodial extensions emanating from CD4 + T cells make contact with HIV virions sequestered deep within a 3D network of surface-accessible compartments in the dendritic cell. Viruses are detected at the membrane surfaces of both dendritic cells and T cells, but virions are not released passively at the synapse instead, virus transfer requires the engagement of T-cell CD4 receptors. The relative seclusion of T cells from the extracellular milieu, the burial of the site of HIV transfer, and the receptor-dependent initiation of virion transfer by T cells highlight unique aspects of cell-cell HIV transmission.
Tailoring Surface Self‐Organization for Nanoscale Polygonal Morphology on Germanium
Publisher: Wiley
Date: 10-04-2001
Abstract: The evolution of polygonal‐shaped nanoholes on the (100) surface of germanium, aided by focused ion beam induced self‐organization, is presented. The energetic beam of ions creates a viscous phase which, at a thermodynamical minimum, leads to surface self‐organization. A directed viscous‐flow along the predefined nanoholes provides well‐ordered polygonal nanostructures, ranging from triangles to hexagons and octagons, as desired. The amorphization exhibiting a confined viscous‐flow at the walls of nanoholes is attributed to the localized melting zones induced by site‐specific thermal spikes during ion irradiation, as revealed by microscopy and molecular dynamics studies. This leads to a local self‐organization in the vicinity of each circular nanohole via a viscous‐fingering process at the nanoscale. Such controlled self‐organization, with the help of a predefined scanning grid, transforms the circular holes into the desired polygonal shape. The present morphology manipulation promises to surmount the barriers concerning the size reduction efforts in the field of nanofabrication.
Evaporative preconcentration and cryopreservation of fluorescent analytes using superhydrophobic surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SM07127D
Graphene encapsulation enabled high-throughput atom probe tomography of liquid specimens
Publisher: Elsevier BV
Date: 09-2020
Rapid prototyping of highly ordered subwavelength silicon nanostructures with enhanced light trapping
Publisher: Elsevier BV
Date: 08-2019
Application of Fibre Bragg Grating Sensors in Strain Monitoring and Fracture Recovery of Human Femur Bone
Publisher: MDPI AG
Date: 19-08-2020
DOI: 10.3390/BIOENGINEERING7030098
Abstract: Fibre Bragg Grating (FBG) sensors are gaining popularity in biomedical engineering. However, specific standards for in vivo testing for their use are absolutely limited. In this study, in vitro experimental tests were performed to investigate the behaviors and applications of gratings attached to intact and fractured thighbone for a range of compression loading ( N) based around some usual daily activities. The wavelength shifts and the corresponding strain sensitivities of the FBG sensors were measured to determine their effectiveness in monitoring the femoral fracture healing process. Four different arrangements of FBG sensors were selected to measure strains at different critical locations on the femoral sawbones surface. Data obtained for intact and plated sawbones were compared using both embedded longitudinal and coiled FBG arrays. Strains were measured close to the fracture, posterior linea aspera and popliteal surface areas, as well as at the proximal and distal ends of the synthetic femur their responses are discussed herein. The gratings on the longitudinally secured FBG arrays were found to provide high levels of sensitivity and precise measurements, even for relatively small loads ( N). Nevertheless, embedding angled FBG sensors is essential to measure the strain generated by applied torque on the femur bone. The maximum recorded strain of the plated femur was 503.97 µε for longitudinal and −274.97 µε for coiled FBG arrays, respectively. These project results are important to configure effective arrangements and orientations of FBG sensors with respect to fracture position and fixation implant for future in vivo experiments.
Shape differentiation of freeform surfaces using a similarity measure based on an integral of Gaussian curvature
Publisher: Elsevier BV
Date: 03-2008
Modeling and fabrication of scale-like cantilever for cell capturing
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033744
Ion-Induced Bending with Applications for High-Resolution Electron Imaging of Nanometer-Sized Samples
Publisher: American Chemical Society (ACS)
Date: 02-11-2021
Chemical mapping of mammalian cells by atom probe tomography
Publisher: Elsevier BV
Date: 05-2012
Modulating surface stiffness of polydimethylsiloxane (PDMS) with kiloelectronvolt ion patterning
Publisher: IOP Publishing
Date: 12-05-2015
Modeling wrinkles on smooth surfaces for footwear design
Publisher: Elsevier BV
Date: 07-2005
Preparation of a soft and interconnected macroporous hydroxypropyl cellulose methacrylate scaffold for adipose tissue engineering
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TB00446E
Correlative 3D imaging of whole mammalian cells with light and electron microscopy
Publisher: Elsevier BV
Date: 12-2011
Bridging structure and mechanics of three-dimensional porous hydrogel with X-ray ultramicroscopy and atomic force microscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA10942F
Abstract: By combining phase contrast X-ray ultramicroscopy and nanoindentation with atomic force microscopy, the mechanics of in idual hydrogel pores as well as their collective performance as a scaffold can be modelled and simulated.
Nanoscale Focused Ion Beam Tomography of Single Bacterial Cells for Assessment of Antibiotic Effects
Publisher: Oxford University Press (OUP)
Date: 04-03-2014
DOI: 10.1017/S1431927614000026
Abstract: Antibiotic resistance is a major risk to human health, and to provide valuable insights into mechanisms of resistance, innovative methods are needed to examine the cellular responses to antibiotic treatment. Focused ion beam tomography is proposed to image and assess the detailed three-dimensional (3D) ultrastructure of single bacterial cells. By iteratively removing slices of thickness in the order of 10 nm, high magnification 2D images can be acquired by scanning electron microscopy at single-digit nanometer resolution. In this study, Klebsiella pneumoniae was treated with polymyxin B, and 3D models of both cell envelope and cytoplasm regions containing the nucleoid and ribosomes were reconstructed. The 3D volume containing the nucleoid and ribosomes was significantly smaller, and the cell length along the longitudinal axis was extended by 40% in the treated cells, implying stress responses to the drug treatment. More than a 200% increase in protrusions per unit surface area on the cell envelope was observed in the curvature analysis after treatment. Experiments by conventional transmission electron microscopy and atomic force microscopy were also performed, followed by comparison and discussions. In conclusion, the proposed 3D imaging method and associated analysis provide a unique tool for the assessment of antibiotic effects on multidrug-resistant bacteria at nanometer resolution.
Injectable 3D Hydrogel Scaffold with Tailorable Porosity Post‐Implantation
Publisher: Wiley
Date: 22-10-2013
Abstract: Since rates of tissue growth vary significantly between tissue types, and also between in iduals due to differences in age, dietary intake, and lifestyle‐related factors, engineering a scaffold system that is appropriate for personalized tissue engineering remains a significant challenge. In this study, a gelatin‐hydroxyphenylpropionic acid/carboxylmethylcellulose‐tyramine (Gtn‐HPA/CMC‐Tyr) porous hydrogel system that allows the pore structure of scaffolds to be altered in vivo after implantation is developed. Cross‐linking of Gtn‐HPA/CMC‐Tyr hydrogels via horseradish peroxidase oxidative coupling is examined both in vitro and in vivo. Post‐implantation, further alteration of the hydrogel structure is achieved by injecting cellulase enzyme to digest the CMC component of the scaffold this treatment yields a structure with larger pores and higher porosity than hydrogels without cellulase injection. Using this approach, the pore sizes of scaffolds are altered in vivo from 32–87 μm to 74–181 μm in a user‐controled manner. The hydrogel is biocompatible to COS‐7 cells and has mechanical properties similar to those of soft tissues. The new hydrogel system developed in this work provides clinicians with the ability to tailor the structure of scaffolds post‐implantation depending on the growth rate of a tissue or an in idual's recovery rate, and could thus be ideal for personalized tissue engineering.
Self-Assembled Enzyme Nanoparticles for Carbon Dioxide Capture
Publisher: American Chemical Society (ACS)
Date: 29-04-2016
DOI: 10.1021/ACS.NANOLETT.6B01121
Abstract: Enzyme-based processes have shown promise as a sustainable alternative to amine-based processes for carbon dioxide capture. In this work, we have engineered carbonic anhydrase nanoparticles that retain 98% of hydratase activity in comparison to their free counterparts. Carbonic anhydrase was fused with a self-assembling peptide that facilitates the noncovalent assembly of the particle and together were recombinantly expressed from a single gene construct in Escherichia coli. The purified enzymes, when subjected to a reduced pH, form 50-200 nm nanoparticles. The CO2 capture capability of enzyme nanoparticles was demonstrated at ambient (22 ± 2 °C) and higher (50 °C) temperatures, under which the nanoparticles maintain their assembled state. The carrier-free enzymatic nanoparticles demonstrated here offer a new approach to stabilize and reuse enzymes in a simple and cost-effective manner.
Printing in situ tissue sealant with visible-light-crosslinked porous hydrogel
Publisher: IOP Publishing
Date: 17-05-2019
Enhanced light-matter interactions in size tunable graphene-gold nanomesh
Publisher: Springer Science and Business Media LLC
Date: 03-2020
DOI: 10.1557/MRC.2019.162
Author Correction: Selenium–GPX4 axis protects follicular helper T cells from ferroptosis
Publisher: Springer Science and Business Media LLC
Date: 04-10-2021
Focused Ion Beam Direct Fabrication of Subwavelength Nanostructures on Silicon for Multicolor Generation
Publisher: Wiley
Date: 13-07-2018
Multidimensional characterisation of biomechanical structures by combining Atomic Force Microscopy and Focused Ion Beam: A study of the rat whisker
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.ACTBIO.2015.03.028
Abstract: Understanding the heterogeneity of biological structures, particularly at the micro/nano scale can offer insights valuable for multidisciplinary research in tissue engineering and biomimicry designs. Here we propose to combine nanocharacterisation tools, particularly Focused Ion Beam (FIB) and Atomic Force Microscopy (AFM) for three dimensional mapping of mechanical modulus and chemical signatures. The prototype platform is applied to image and investigate the fundamental mechanics of the rat face whiskers, a high-acuity sensor used to gain detailed information about the world. Grazing angle FIB milling was first applied to expose the interior cross section of the rat whisker s le, followed by a "lift-out" method to retrieve and position the target s le for further analyses. AFM force spectroscopy measurements revealed a non-uniform pattern of elastic modulus across the cross section, with a range from 0.8GPa to 13.5GPa. The highest elastic modulus was found at the outer cuticle region of the whisker, and values gradually decreased towards the interior cortex and medulla regions. Elemental mapping with EDS confirmed that the interior of the rat whisker is dominated by C, O, N, S, Cl and K, with a significant change of elemental distribution close to the exterior cuticle region. Based on these data, a novel comprehensive three dimensional (3D) elastic modulus model was constructed, and stress distributions under realistic conditions were investigated with Finite Element Analysis (FEA). The simulations could well account for the passive whisker deflections, with calculated resonant frequency as well as force-deflection for the whiskers being in good agreement with reported experimental data. Limitations and further applications are discussed for the proposed FIB/AFM approach, which holds good promise as a unique platform to gain insights on various heterogeneous biomaterials and biomechanical systems.
Direct Imaging of Liquid–Nanoparticle Interfaces with Atom Probe Tomography
Publisher: American Chemical Society (ACS)
Date: 07-08-2020
Modeling and simulation of milling frozen biological samples by focused ion beam
Publisher: ASMEDC
Date: 2008
Abstract: Focused Ion Beam (FIB) has been used widely for s le preparation in material research and nanoscale device fabrication. The introduction of FIB system to biological s les preparation, especially for frozen s les, provides the potential to produce delicate submicron geometries on the s les, as well as the potential to be fully digitally controlled. In this paper, we first study the ion interactions with water and different cryoprotectants, and the sputtering yields under different conditions are estimated as the milling rate. A geometric simulation model is also proposed which can be used as a process planning tool to perform cryo-sectioning by FIB. Finally, discussions and suggestions for future work are presented.
Electrical circuits from capillary flow driven evaporation deposition of carbon nanotube ink in non-porous V-grooves
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.JCIS.2011.07.019
Abstract: Low cost pliable electronics portend the advancement of novel inexpensive microfluidic electrochemical devices. In the direct printing approach, the manner of deposition of conductive material from a liquid suspension to ensure electrical continuity is crucial. We describe here an approach in which V-groove networks that make up the path of circuitry are first scribed on non-porous inexpensive surfaces. Liquid drops of carbon nanotube ink are then placed on the surface adjacent to the V-grooves to enable wicking to produce the electrical circuit. This method essentially bypasses the need for inkjet printing. We investigate the basic efficacy of the conductive networks developed using this approach and demonstrate its use in generating electrically driven liquid flow of particles in a simple open capillary channel.
Selenium–GPX4 axis protects follicular helper T cells from ferroptosis
Publisher: Springer Science and Business Media LLC
Date: 19-08-2021
DOI: 10.1038/S41590-021-00996-0
Abstract: Follicular helper T (T
Transcriptomic responses of a New Delhi metallo-β-lactamase-producing Klebsiella pneumoniae isolate to the combination of polymyxin B and chloramphenicol
Publisher: Elsevier BV
Date: 08-2020
Tuning the surface properties of hydrogel at the nanoscale with focused ion irradiation
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4SM01061B
Abstract: With the site-specific machining capability of Focused Ion Beam (FIB) irradiation, we aim to tailor the surface morphology and physical attributes of biocompatible hydrogel at the nano/micro scale particularly for tissue engineering and other biomedical studies.
Automated patterning and probing with multiple nanoscale tools for single-cell analysis
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.MICRON.2017.06.002
Abstract: The nano-manipulation approach that combines Focused Ion Beam (FIB) milling and various imaging and probing techniques enables researchers to investigate the cellular structures in three dimensions. Such fusion approach, however, requires extensive effort on locating and examining randomly-distributed targets due to limited Field of View (FOV) when high magnification is desired. In the present study, we present the development that automates 'pattern and probe' particularly for single-cell analysis, achieved by computer aided tools including feature recognition and geometric planning algorithms. Scheduling of serial FOVs for imaging and probing of multiple cells was considered as a rectangle covering problem, and optimal or near-optimal solutions were obtained with the heuristics developed. FIB milling was then employed automatically followed by downstream analysis using Atomic Force Microscopy (AFM) to probe the cellular interior. Our strategy was applied to examine bacterial cells (Klebsiella pneumoniae) and achieved high efficiency with limited human interference. The developed algorithms can be easily adapted and integrated with different imaging platforms towards high-throughput imaging analysis of single cells.
Localized deoxygenation and direct patterning of graphene oxide films by focused ion beams
Publisher: American Chemical Society (ACS)
Date: 04-10-2012
DOI: 10.1021/LA303369M
Abstract: Exposure to controlled doses (~4.65 × 10(-3) to 2.79 × 10(-2) nC/μm(2) ion fluence) of Ga ions via a focused ion beam (FIB) deoxygenates graphene oxide (GO) and increases the electrical conductivity in 100 × 100 μm(2) patches by several orders of magnitude compared to that in unexposed GO. Raman spectra and the carbon/oxygen ratio in exposed areas are indicative of chemically reduced graphene oxide (rGO). This novel FIB-induced conversion technique is harnessed for the direct imprinting of complex micrometer-scale shapes and sub-20-nm lines of rGO in insulating films and flakes of GO establishing the capability of generating features varying in size from approximately tens of nanometers to approximately hundreds of micrometers in a maskless, efficient manner.
Elastic modulus of rat whiskers—A key biomaterial in the rat whisker sensory system
Publisher: Elsevier BV
Date: 12-2013
Controlled graphene encapsulation: a nanoscale shield for characterising single bacterial cells in liquid
Publisher: IOP Publishing
Date: 02-07-2018
Abstract: High-resolution single-cell imaging in their native or near-native state has received considerable interest for decades. In this research, we present an innovative approach that can be employed to study both morphological and nano-mechanical properties of hydrated single bacterial cells. The proposed strategy is to encapsulate wet cells with monolayer graphene with a newly developed water membrane approach, followed by imaging with both electron microscopy (EM) and atomic force microscopy (AFM). A computational framework was developed to provide additional insights, with the detailed nanoindentation process on graphene modelled based on the finite element method. The model was first validated by calibration with polymer materials of known properties, and the contribution of graphene was then studied and corrected to determine the actual moduli of the encapsulated hydrated s le. Application of the proposed approach was performed on hydrated bacterial cells (Klebsiella pneumoniae) to correlate the structural and mechanical information. EM and energy-dispersive x-ray spectroscopy imaging confirmed that the cells in their near-native stage can be studied inside the miniaturised environment enabled with graphene encapsulation. The actual moduli of the encapsulated hydrated cells were determined based on the developed computational model in parallel, with results comparable with those acquired with wet AFM. It is expected that the successful establishment of controlled graphene encapsulation offers a new route for probing liquid/live cells with scanning probe microscopy, as well as correlative imaging of hydrated s les for both biological and material sciences.
Assessing functional and shape differentiation within a family of products
Publisher: ASMEDC
Date: 2008
Abstract: Market differentiation strategies must identify competitive advantages when offering a line of products varying in features, price, quality, and/or aesthetics. Although this concept is well-known, many companies still have difficulties positioning their own products within their own product lines and against competitors. Few approaches combine two or more facets to answer the product differentiation problem. In this study, two novel indices are proposed to audit shape and functional differentiation within a family of products. The shape index appraises the shape similarity between the products upon digitization, while the functional assessment is based on functions characteristics of the product. Customers’ perception data is obtained experimentally and compared to these indices to validate the result. Pairs of products are evaluated, and the average scores are considered as the indices for a product family. A case study illustrates the usage of these two indices and performance of these tools as well. This approach can be used during detailed studies as well as early stages of the design process to help validate product family positioning.
Methods of Preparing Nanoscale Vitreous Ice Needles for High-Resolution Cryogenic Characterization
Publisher: American Chemical Society (ACS)
Date: 04-08-2022
DOI: 10.1021/ACS.NANOLETT.2C01495
Abstract: New high-resolution imaging methods for biological s les such as atom probe tomography (APT), facilitated by the invention of laser-pulsed atom probes and cryo-transfer procedures, have recently emerged. However, ensuring the vitreous state of the fabricated aqueous needle-shaped APT s les remains a challenge despite it being crucial for characterizing biomolecules such as proteins and cellular architectures in their near-native state. Our work investigated three potential approaches: (1) open microcapillary (OMC) method, (2) high-pressure freezing method (HPF), and (3) graphene encapsulation method. Diffraction patterns of the needle specimens acquired by cryo-TEM have demonstrated the vitreous state of the ice needles, although limited to the tip regions, has been achieved with the three proposed approaches. With the capability to prepare vitreous ice needles from hydrated s les of up to ∼200 μm thickness (HPF), combined use of the three approaches opens new avenues for future near-atomic imaging of biological cells in their near-native state.
A study of angular effects in focused ion beam milling of water ice
Publisher: IOP Publishing
Date: 29-07-2008
A quantitative study on focused on beam milling in a cryogenic environment
Publisher: Oxford University Press (OUP)
Date: 08-2008
DOI: 10.1017/S1431927608083062
Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008
Controlled Manipulation and Multiscale Modeling of Suspended Silicon Nanostructures under Site-Specific Ion Irradiation
Publisher: American Chemical Society (ACS)
Date: 08-01-2020
Abstract: In this work, controlled bidirectional deformation of suspended nanostructures by site-specific ion irradiation is presented. Multiscale modeling of the bidirectional deformation of nanostructures by site-specific ion irradiation is presented, incorporating molecular dynamics (MD) simulations together with finite element analysis, to substantiate the bending mechanism. Strain engineering of the free-standing nanostructure is employed for controlled deformation through site-specific kiloelectronvolt ion irradiation experimentally using a focused ion beam. We report the detailed bending mechanism of suspended silicon (Si) nanostructures through ion-induced irradiations. MD simulations are presented to understand the ion-solid interactions, defects formation in the silicon nanowire. The atomic-scale simulations reveal that the ion irradiation-induced bidirectional bending occurs through the development of localized tensile-compressive stresses in the lattice due to defect formation associated with atomic displacements. With an increasing ion dose, the evolution of localized tensile to compressive stress is observed, developing the alternate bending directions calculated through finite element analysis. The findings of multiscale modeling are in excellent agreement with the bidirectional nature of bending observed through the experiments. The developed in situ approach for bidirectional controlled manipulation of nanostructures in this work can be used for nanofabrication of numerous novel three-dimensional configurations and can provide a route toward functional nanostructures and devices.
Structure–Interaction Relationship of Polymyxins with the Membrane of Human Kidney Proximal Tubular Cells
Publisher: American Chemical Society (ACS)
Date: 03-07-2020
Compositional mapping of the surface and interior of mammalian cells at submicrometer resolution
Publisher: American Chemical Society (ACS)
Date: 26-01-2011
DOI: 10.1021/AC1030607
Three-Dimensional Chemical Mapping of a Single Protein in the Hydrated State with Atom Probe Tomography
Publisher: American Chemical Society (ACS)
Date: 10-03-2020
Synergistic killing of NDM-producing MDR Klebsiella pneumoniae by two 'old' antibiotics-polymyxin B and chloramphenicol.
Publisher: Oxford University Press (OUP)
Date: 28-05-2015
DOI: 10.1093/JAC/DKV135
Enhanced light trapping by focused ion beam (FIB) induced self-organized nanoripples on germanium (100) surface
Publisher: AIP Publishing
Date: 03-2018
DOI: 10.1063/1.5021735
Abstract: In this paper, we demonstrate enhanced light trapping by self-organized nanoripples on the germanium surface. The enhanced light trapping leading to high absorption of light is confirmed by the experimental studies as well as the numerical simulations using the finite-difference time-domain method. We used gallium ion (Ga+) focused ion beam to enable the formation of the self-organized nanoripples on the germanium (100) surface. During the fabrication, the overlap of the scanning beam is varied from zero to negative value and found to influence the orientation of the nanoripples. Evolution of nanostructures with the variation of beam overlap is investigated. Parallel, perpendicular, and randomly aligned nanoripples with respect to the scanning direction are obtained via manipulation of the scanning beam overlap. 95% broadband absorptance is measured in the visible electromagnetic region for the nanorippled germanium surface. The reported light absorption enhancement can significantly improve the efficiency of germanium-silicon based photovoltaic systems.
Pulsed-voltage atom probe tomography of low conductivity and insulator materials by application of ultrathin metallic coating on nanoscale specimen geometry
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.ULTRAMIC.2017.05.002
Abstract: We present a novel approach for analysis of low-conductivity and insulating materials with conventional pulsed-voltage atom probe tomography (APT), by incorporating an ultrathin metallic coating on focused ion beam prepared needle-shaped specimens. Finite element electrostatic simulations of coated atom probe specimens were performed, which suggest remarkable improvement in uniform voltage distribution and subsequent field evaporation of the insulated s les with a metallic coating of approximately 10nm thickness. Using design of experiment technique, an experimental investigation was performed to study physical vapor deposition coating of needle specimens with end tip radii less than 100nm. The final geometries of the coated APT specimens were characterized with high-resolution scanning electron microscopy and transmission electron microscopy, and an empirical model was proposed to determine the optimal coating thickness for a given specimen size. The optimal coating strategy was applied to APT specimens of resin embedded Au nanospheres. Results demonstrate that the optimal coating strategy allows unique pulsed-voltage atom probe analysis and 3D imaging of biological and insulated s les.
FIB fabrication of highly ordered vertical Gaussian pillar nanostructures on silicon
Publisher: IEEE
Date: 07-2017
Quantification of ZnO Nanoparticle Uptake, Distribution, and Dissolution within Individual Human Macrophages
Publisher: American Chemical Society (ACS)
Date: 11-11-2013
DOI: 10.1021/NN403118U
Abstract: The usefulness of zinc oxide (ZnO) nanoparticles has led to their wide distribution in consumer products, despite only a limited understanding of how this nanomaterial behaves within biological systems. From a nanotoxicological viewpoint the interaction(s) of ZnO nanoparticles with cells of the immune system is of specific interest, as these nanostructures are readily phagocytosed. In this study, rapid scanning X-ray fluorescence microscopy was used to assay the number ZnO nanoparticles associated with ∼1000 in idual THP-1 monocyte-derived human macrophages. These data showed that nanoparticle-treated cells endured a 400% elevation in total Zn levels, 13-fold greater than the increase observed when incubated in the presence of an equitoxic concentration of ZnCl2. Even after excluding the contribution of internalized nanoparticles, Zn levels in nanoparticle treated cells were raised ∼200% above basal levels. As dissolution of ZnO nanoparticles is critical to their cytotoxic response, we utilized a strategy combining ion beam milling, X-ray fluorescence and scanning electron microscopy to directly probe the distribution and composition of ZnO nanoparticles throughout the cellular interior. This study demonstrated that correlative photon and ion beam imaging techniques can provide both high-resolution and statistically powerful information on the biology of metal oxide nanoparticles at the single-cell level. Our approach promises ready application to broader studies of phenomena at the interface of nanotechnology and biology.
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