Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
876
result(s) for
"Microtechnology"
Sort by:
Soft micromachines with programmable motility and morphology
Nature provides a wide range of inspiration for building mobile micromachines that can navigate through confined heterogenous environments and perform minimally invasive environmental and biomedical operations. For example, microstructures fabricated in the form of bacterial or eukaryotic flagella can act as artificial microswimmers. Due to limitations in their design and material properties, these simple micromachines lack multifunctionality, effective addressability and manoeuvrability in complex environments. Here we develop an origami-inspired rapid prototyping process for building self-folding, magnetically powered micromachines with complex body plans, reconfigurable shape and controllable motility. Selective reprogramming of the mechanical design and magnetic anisotropy of body parts dynamically modulates the swimming characteristics of the micromachines. We find that tail and body morphologies together determine swimming efficiency and, unlike for rigid swimmers, the choice of magnetic field can subtly change the motility of soft microswimmers.
In nature many microorganisms are able to change their shape to adapt to the changes in the environment. Inspired by this phenomenon, here Huang
et al
. build artificial microswimmers with body and flagellum made of programmable hydrogel-based materials incorporated with magnetic nanoparticles.
Journal Article
Boron Nitride Nanotube-Mediated Stimulation of Cell Co-Culture on Micro-Engineered Hydrogels
In this paper, we describe the effects of the combination of topographical, mechanical, chemical and intracellular electrical stimuli on a co-culture of fibroblasts and skeletal muscle cells. The co-culture was anisotropically grown onto an engineered micro-grooved (10 µm-wide grooves) polyacrylamide substrate, showing a precisely tuned Young's modulus (∼ 14 kPa) and a small thickness (∼ 12 µm). We enhanced the co-culture properties through intracellular stimulation produced by piezoelectric nanostructures (i.e., boron nitride nanotubes) activated by ultrasounds, thus exploiting the ability of boron nitride nanotubes to convert outer mechanical waves (such as ultrasounds) in intracellular electrical stimuli, by exploiting the direct piezoelectric effect. We demonstrated that nanotubes were internalized by muscle cells and localized in both early and late endosomes, while they were not internalized by the underneath fibroblast layer. Muscle cell differentiation benefited from the synergic combination of topographical, mechanical, chemical and nanoparticle-based stimuli, showing good myotube development and alignment towards a preferential direction, as well as high expression of genes encoding key proteins for muscle contraction (i.e., actin and myosin). We also clarified the possible role of fibroblasts in this process, highlighting their response to the above mentioned physical stimuli in terms of gene expression and cytokine production. Finally, calcium imaging-based experiments demonstrated a higher functionality of the stimulated co-cultures.
Journal Article
Why middle-sized matters: Quantum realism, minds and the Problem of Macro-Objects
The Problem of Macro-Objects concerns how three-dimensional, middle-sized objects, such as scientists and their measuring devices, can exist in a quantum world. This paper discusses the problem for wave function realism and the primitive ontology approach to quantum mechanics, focussing on Alyssa Ney’s recent two-stage solution, in which macro-objects are functionally reduced to micro-objects and micro-objects are parts of a whole in which they are grounded (the wave function field). It raises metaphysical difficulties with this proposal which a hylomorphic account of wholes may be able to address, noting possible implications for one’s philosophy of mind depending on one’s preferred solution to the Measurement Problem.
Journal Article
Fabrication and practical applications of molybdenum disulfide nanopores
Among the different developed solid-state nanopores, nanopores constructed in a monolayer of molybdenum disulfide (MoS
2
) stand out as powerful devices for single-molecule analysis or osmotic power generation. Because the ionic current through a nanopore is inversely proportional to the thickness of the pore, ultrathin membranes have the advantage of providing relatively high ionic currents at very small pore sizes. This increases the signal generated during translocation of biomolecules and improves the nanopores’ efficiency when used for desalination or reverse electrodialysis applications. The atomic thickness of MoS
2
nanopores approaches the inter-base distance of DNA, creating a potential candidate for DNA sequencing. In terms of geometry, MoS
2
nanopores have a well-defined vertical profile due to their atomic thickness, which eliminates any unwanted effects associated with uneven pore profiles observed in other materials. This protocol details all the necessary procedures for the fabrication of solid-state devices. We discuss different methods for transfer of monolayer MoS
2
, different approaches for the creation of nanopores, their applicability in detecting DNA translocations and the analysis of translocation data through open-source programming packages. We present anticipated results through the application of our nanopores in DNA translocations and osmotic power generation. The procedure comprises four parts: fabrication of devices (2–3 d), transfer of MoS
2
and cleaning procedure (24 h), the creation of nanopores within MoS
2
(30 min) and performing DNA translocations (2–3 h). We anticipate that our protocol will enable large-scale manufacturing of single-molecule-analysis devices as well as next-generation DNA sequencing.
This protocol describes the fabrication and practical applications of molybdenum disulfide (MoS
2
) nanopores. The procedure contains different methods for the transfer of monolayer MoS
2
, nanopore creation, and data acquisition and analysis.
Journal Article
Machining protein microcrystals for structure determination by electron diffraction
We demonstrate that ion-beam milling of frozen, hydrated protein crystals to thin lamella preserves the crystal lattice to near-atomic resolution. This provides a vehicle for protein structure determination, bridging the crystal size gap between the nanometer scale of conventional electron diffraction and micron scale of synchrotron microfocus beamlines. The demonstration that atomic information can be retained suggests that milling could provide such detail on sections cut from vitrified cells.
Journal Article
Freeform micropatterning of living cells into cell culture medium using direct inkjet printing
Microfabrication methods have widely been used to control the local cellular environment on a micron scale. However, accurately mimicking the complexity of the
in vivo
tissue architecture while maintaining the freedom of form and design is still a challenge when co-culturing multiple types of cells on the same substrate. For the first time, we present a drop-on-demand inkjet printing method to directly pattern living cells into a cell-friendly liquid environment. High-resolution control of cell location is achieved by precisely optimizing printing parameters with high-speed imaging of cell jetting and impacting behaviors. We demonstrated the capabilities of the direct cell printing method by co-printing different cells into various designs, including complex gradient arrangements. Finally, we applied this technique to investigate the influence of the heterogeneity and geometry of the cell population on the infectivity of seasonal H1N1 influenza virus (PR8) by generating A549 and HeLa cells printed in checkboard patterns of different sizes in a medium-filled culture dish. Direct inkjet cell patterning can be a powerful and versatile tool for both fundamental biology and applied biotechnology.
Journal Article
Fabrication and use of silicon hollow-needle arrays to achieve tissue nanotransfection in mouse tissue in vivo
Tissue nanotransfection (TNT) is an electromotive gene transfer technology that was developed to achieve tissue reprogramming in vivo. This protocol describes how to fabricate the required hardware, commonly referred to as a TNT chip, and use it for in vivo TNT. Silicon hollow-needle arrays for TNT applications are fabricated in a standardized and reproducible way. In <1 s, these silicon hollow-needle arrays can be used to deliver plasmids to a predetermined specific depth in murine skin in response to pulsed nanoporation. Tissue nanotransfection eliminates the need to use viral vectors, minimizing the risk of genomic integration or cell transformation. The TNT chip fabrication process typically takes 5–6 d, and in vivo TNT takes 30 min. This protocol does not require specific expertise beyond a clean room equipped for basic nanofabrication processes.
Sen and colleagues describe a protocol for the fabrication of silicon hollow-needle arrays to achieve tissue nanotransfection of mouse skin.
Journal Article
Inflammation-on-a-Chip: Probing the Immune System Ex Vivo
Inflammation is the typical result of activating the host immune system against pathogens, and it helps to clear microbes from tissues. However, inflammation can occur in the absence of pathogens, contributing to tissue damage and leading to disease. Understanding how immune cells coordinate their activities to initiate, modulate, and terminate inflammation is key to developing effective interventions to preserve health and combat diseases. Towards this goal, inflammation-on-a-chip tools provide unique features that greatly benefit the study of inflammation. They reconstitute tissue environments in microfabricated devices and enable real-time, high-resolution observations and quantification of cellular activities relevant to inflammation. We review here recent advances in inflammation-on-a-chip technologies and highlight the biological insights and clinical applications enabled by these emerging tools.
Inflammation is a cascade of immune responses that is involved in host defense against invading pathogens, as well as in the pathogenesis of a variety of chronic diseases such as heart diseases, cancer, Alzheimer’s disease, and diabetes.
Understanding the initiation, mediation, and termination of inflammation could help to uncover new treatments and early interventions to prevent complications.
The cellular components involved in inflammation play a significant role in host defense and the pathology of many diseases. However, the conventional techniques for studying immune cells in the inflammation are limited in diversity and performance.
Inflammation-on-a-chip technologies enable precise control and measurements of immune cells in engineered microenvironments from the single-cell to the organ level. Inflammation-on-a-chip technologies are also increasingly capable of diagnosis and monitoring of infections and inflammatory diseases.
Journal Article
Comparison of mean values and entropy in accelerometry time series from two microtechnology sensors recorded at 100 vs. 1000 Hz during cumulative tackles in young elite rugby league players
Several microtechnology devices quantify the external load of team sports using Global Positioning Systems sampling at 5, 10, or 15 Hz. However, for short, explosive actions, such as collisions, these sample rates may be limiting. It is known that very high-frequency sampling is capable of capturing changes in actions over a short period of time. Therefore, the aim of this study was to compare the mean acceleration and entropy values obtained from 100 Hz and 1000 Hz tri-axial accelerometers in tackling actions performed by rugby players. A total of 11 elite adolescent male rugby league players (mean ± SD; age: 18.5 ± 0.5 years; height: 179.5 ± 5.0 cm; body mass: 88.3 ± 13.0 kg) participate in this study. Participants performed tackles (n = 200), which were recorded using two triaxial accelerometers sampling at 100 Hz and 1000 Hz, respectively. The devices were placed together inside the Lycra vests on the players’ backs. The mean acceleration, sample entropy (SampEn), and approximate entropy (ApEn) were analyzed. In mean acceleration, the 1000 Hz accelerometer obtained greater values (p < 0.05). However, SampEn and ApEn were greater with the 100 Hz accelerometer (p < 0.05). A large relationship was observed between the two devices in all the parameters analyzed (R2 > 0.5; p < 0.0001). Sampling frequency can affect the quality of the data collected, and a higher sampling frequency potentially allows for the collection of more accurate motion data. A frequency of 1000 Hz may be suitable for recording short and explosive actions.
Journal Article