Planar Format Research Articles

Planar or Spatial: Exploring Design Aspects and Challenges for Presentations in Virtual Reality with No-coding Interface

The proliferation of virtual reality (VR) has led to its increasing adoption as an immersive medium for delivering presentations, distinct from other VR experiences like games and 360-degree videos by sharing information in richly interactive environments. However, creating engaging VR presentations remains a challenging and time-consuming task for users, hindering the full realization of VR presentation's capabilities. This research aims to explore the potential of VR presentation, analyze users' opinions, and investigate these via providing a user-friendly no-coding authoring tool. Through an examination of popular presentation software and interviews with seven professionals, we identified five design aspects and four design challenges for VR presentations. Based on the findings, we developed VRStory, a prototype for presentation authoring without coding to explore the design aspects and strategies for addressing the challenges. VRStory offers a variety of predefined and customizable VR elements, as well as modules for layout design, navigation control, and asset generation. A user study was then conducted with 12 participants to investigate their opinions and authoring experience with VRStory. Our results demonstrated that, while acknowledging the advantages of immersive and spatial features in VR, users often have a consistent mental model for traditional 2D presentations and may still prefer planar and static formats in VR for better accessibility and efficient communication. We finally shared our learned design considerations for future development of VR presentation tools, emphasizing the importance of balancing of promoting immersive features and ensuring accessibility.

Patterned thin film enzyme electrodes via spincoating and glutaraldehyde vapor crosslinking: towards scalable fabrication of integrated sensor-on-CMOS devices.

Effective continuous glucose monitoring solutions require consistent sensor performance over the lifetime of the device, a manageable variance between devices, and the capability of high volume, low cost production. Here we present a novel and microfabrication-compatible method of depositing and stabilizing enzyme layers on top of planar electrodes that can aid in the mass production of sensors while also improving their consistency. This work is focused on the fragile biorecognition layer as that has been a critical difficulty in the development of microfabricated sensors. We test this approach with glucose oxidase (GOx) and evaluate the sensor performance with amperometric measurements of in vitro glucose concentrations. Spincoating was used to deposit a uniform enzyme layer across a wafer, which was subsequently immobilized via glutaraldehyde vapor crosslinking and patterned via liftoff. This yielded an approximately 300 nm thick sensing layer which was applied to arrays of microfabricated platinum electrodes built on blank wafers. Taking advantage of their planar array format, measurements were then performed in high-throughput parallel instrumentation. Due to their thin structure, the coated electrodes exhibited subsecond stabilization times after the bias potential was applied. The deposited enzyme layers were measured to provide a sensitivity of 2.3 ± 0.2 μA mM-1 mm-2 with suitable saturation behavior and minimal performance shift observed over extended use. The same methodology was then demonstrated directly on top of wireless CMOS potentiostats to build a monolithic sensor with similar measured performance. This work demonstrates the effectiveness of the combination of spincoating and vapor stabilization processes for wafer scale enzymatic sensor functionalization and the potential for scalable fabrication of monolithic sensor-on-CMOS devices.

Experimental demonstration of optical trapping and manipulation with multifunctional metasurface.

Chip-scale optical tweezers, which are usually implemented in a planar format without using bulky diffractive optical elements, are recognized as a promising candidate to be integrated with a lab-on-a-chip system. However, traditional chip-scale optical tweezers are often static and allow for only one type of manipulation functionality since the geometrical parameters of the tweezers are fixed. Herein, we introduce a new, to the best of our knowledge, class of on-chip optical tweezers for diverse types of manipulation of micro-particles. Utilizing both the propagation phase and Pancharatnam-Berry phase, we experimentally demonstrate the spin-dependent trapping, moving, and circling of micro-particles with the transfer of optical gradient force and orbital angular momentum to particles. We further show that the spin angular momentum of the output beam provides an additional degree of freedom to control the spinning rotation of particles. This new type of optical tweezers paves the way for multifunctional and dynamical trapping and manipulation of particles with a lab-on-a-chip system.

Monoplex and multiplex immunoassays: approval, advancements, and alternatives

Immunoassays are a powerful diagnostic tool and are widely used for the quantification of proteins and biomolecules in medical diagnosis and research. Enzyme-linked immunosorbent assay (ELISA) is the most commonly used immunoassay format and allows the detection of biomarkers at a very low concentration. The diagnostic platforms such as enzyme immunoassay (EIA), chemiluminescence (CL) assay, polymerase chain reaction (PCR), flow cytometry (FC), and mass spectrometry (MS) have been used to identify molecular biomarkers. However, these diagnostic tools requiring expensive equipment, long testing time, and qualified personnel that is not always available in small local hospitals with limited resources. The lateral flow immunoassay (LFIA) platform was developed for rapidly obtaining laboratory results and to make urgent decisions in emergency medicine, as well as the recently introduced concept of testing at the site of care (point-of-care, POC). The simultaneous measurement of different substances from a single sample called multiplex assays have become increasingly significant for in vitro quantification of multiple analytes in a single sample, thereby minimising cost, time, and volume. In multiplex immunoassays, the ligands are immobilized either in planar format (flat surface) or on microspheres in suspension that binds to target analytes in sample. The multiplex technology has established itself in proteomic networks and pathways, validation of genomic discoveries, and in the development of clinical biomarkers. In the present review article, various types of monoplex/simplex and complex/multiplex immunoassays have been analysed that are increasingly being applied in laboratory medicine. Also, some advantages and disadvantages of these multiplex assays have also been included such as experimental animals, in vitro tests using cell lines and tissue samples, 3-dimensional modelling and bioprinting, in silico tests, organ-on-chip, and computer modelling.

A bistable, multiport valve enables microformulators creating microclinical analyzers that reveal aberrant glutamate metabolism in astrocytes derived from a tuberous sclerosis patient.

There is a need for valves and pumps that operate at the microscale with precision and accuracy, are versatile in their application, and are easily fabricated. To that end, we developed a new rotary planar multiport valve to faithfully select solutions (contamination = 5.22 ± 0.06 ppb) and a rotary planar peristaltic pump to precisely control fluid delivery (flow rate = 2.4 ± 1.7 to 890 ± 77 μL/min). Both the valve and pump were implemented in a planar format amenable to single-layer soft lithographic fabrication. These planar microfluidics were actuated by a rotary motor controlled remotely by custom software. Together, these two devices constitute an innovative microformulator that was used to prepare precise, high-fidelity mixtures of up to five solutions (deviation from prescribed mixture = ±|0.02 ± 0.02| %). This system weighed less than a kilogram, occupied around 500 cm3, and generated pressures of 255 ± 47 kPa. This microformulator was then combined with an electrochemical sensor creating a microclinical analyzer (μCA) for detecting glutamate in real time. Using the chamber of the μCA as an in-line bioreactor, we compared glutamate homeostasis in human astrocytes differentiated from human-induced pluripotent stem cells (hiPSCs) from a control subject (CC-3) and a Tuberous Sclerosis Complex (TSC) patient carrying a pathogenic TSC2 mutation. When challenged with glutamate, TSC astrocytes took up less glutamate than control cells. These data validate the analytical power of the μCA and the utility of the microformulator by leveraging it to assess disease-related alterations in cellular homeostasis.

Cartography as Spatial Representation: A new assessment of the competing advantages and drawbacks across fields of science

The history of cartography has been marked by the endless search for the perfect form for the representation of the information on a spherical surface manifold into the flat planar format of the printed page or computer screen. Dozens of cartographic formats have been proposed over the centuries from ancient Greek times to the present. This is an issue not just for the mapping of the globe, but in all fields of science where spherical entities are found. The perceptual and representational advantages and drawbacks of many of these formats are considered, particularly in the tension between a unified representation, which is always distorted in some dimension, and a minimally distorted representation, which can only be obtained by segmentation into sectorial patches. The use of these same formats for the mapping of spherical manifolds are evaluated, from quantum physics through the mapping of the brain to the large-scale representation of the cosmos.

Enhanced plasmonic processes in amino-rich plasma polymer films for applications at the biointerface.

A new plasmonic biosensor was developed in a planar chip-based format by coupling the plasmonic properties of gold nanoparticles (Au NPs) with the mechanical and bioadhesive features of unconventional organic thin films deposited from plasma, namely primary amine-based plasma polymer films (PPFs). A self-assembled layer of spherical Au NPs, 12 nm in diameter, was electrostatically immobilized onto optically transparent silanised glass. In the next step, the Au NP layer was coated with an 18 nm polymeric thick PPF layer via the simultaneous polymerization/deposition of a cyclopropylamine (CPA) precursor performed by radio frequency discharge, both in pulsed and in continuous wave modes. The CPA PFF surface plays the dual role of an adsorbent towards negatively charged chemical species as well as an enhancer of plasmonic signals. The biosensor was tested in a proof-of-concept series of experiments of human serum albumin physisorption, and chosen as a model system for blood serum. The peculiar surface features of CPA PPF, before and after the exposure to buffered solution of fluorescein isothiocyanate-labelled human serum albumin (FITC-HSA), were investigated by a multi-technique approach, including UV-visible and X-ray photoelectron spectroscopies, atomic force microscopy, scanning electron microscopy, contact angle and surface free energy measurements. The results showed the very promising potentialities from both bioanalytical and physicochemical points of view in scrutinizing the macromolecule behavior at the biointerface.

Plasmonic Computational Compound-Eye Camera

Recently, we have reported a novel compound-eye camera architecture—one that leverages the great design flexibility of metasurface nanophotonics and the advanced data-processing capabilities of computational imaging, to provide an ultrawide FOV greater than 150° in a planar lensless format.

A universal multiplex assay format for ultra-sensitive cytokine quantification in human serum and plasma

Abstract Quantifying prospective biomarkers of immune signaling in biological samples requires high assay sensitivity. The Simoa Planar Array provides greater sensitivity than ELISA, but has a finite assay menu. This study aimed to develop a universal multiplex ‘homebrew’ planar immunoassay format for development of high sensitivity assays for any analyte. Anchor antibodies specific for a peptide tag were microprinted in microwell plates. The peptide tags were conjugated to analyte-specific capture antibodies via maleimide chemistry, enabling high affinity binding of capture to anchor antibody. Bound sample antigen was sandwiched between the peptide-tagged capture and biotinylated detector antibodies; chemiluminescent detection was used to quantify signal. This ‘homebrew’ approach successfully detected sub picomolar levels of cytokines and chemokines in human serum and plasma in a multiplex assay measuring IL-5, IL-6, IL-10, IL-22, TNFa. When compared to commercially available planar assays the universal planar assay format provided comparable LLOQ and LOD with sample correlation (R2) >0.97 for all analytes tested. The universal planar assay was used to successfully screen multiple antibody pairs for human and mouse biomarkers and to develop robust assays using mouse, rabbit or goat monoclonal and polyclonal antibodies. This universal multiplex planar homebrew assay format combines the accuracy, reproducibility and high sensitivity of Simoa Planar Array technology with total analyte flexibility, and provides assay developers a simple and versatile method to rapidly develop robust high-sensitivity multiplex assays for any analyte of their choice.

Visual attention-aware quality estimation framework for omnidirectional video using spherical Voronoi diagram

Omnidirectional video (ODV) enables viewers to look at every direction from a fixed point and provides a much more immersive experience than traditional 2D video. Assessing the video quality is important for delivering ODV to the end-user with the best possible quality. For this goal, two aspects of ODV should be considered. The first is the spherical nature of ODV and the related projection distortions when the ODV is stored in a planar format. The second is the interactive look-around consumption nature of ODV. Related to this aspect, visual attention, that identifies the regions that attract the viewer’s attention, is important for ODV quality assessment. Considering these aspects, in this paper, we study in particular objective full-reference quality assessment for ODV. To this end, we propose a quality assessment framework based on the spherical Voronoi diagram and visual attention. In this framework, a given ODV is subdivided into multiple planar patches with low projection distortions using the spherical Voronoi diagram. Afterwards, each planar patch is analyzed separately by a quality metric for traditional 2D video, obtaining a quality score for each patch. Then, the patch scores are combined based on visual attention into a final quality score. To validate the proposed framework, we create a dataset of ODVs with scaling and compression distortions, and conduct subjective experiments in order to gather the subjective quality scores and the visual attention data for our ODV dataset. The evaluation of the proposed framework based on our dataset shows that both the use of the spherical Voronoi diagram and visual attention are crucial for achieving state-of-the-art performance.

Injectable Biomedical Devices for Sensing and Stimulating Internal Body Organs.

The rapid pace of progress in implantable electronics driven by novel technology has created devices with unconventional designs and features to reduce invasiveness and establish new sensing and stimulating techniques. Among the designs, injectable forms of biomedical electronics are explored for accurate and safe targeting of deep-seated body organs. Here, the classes of biomedical electronics and tools that have high aspect ratio structures designed to be injected or inserted into internal organs for minimally invasive monitoring and therapy are reviewed. Compared with devices in bulky or planar formats, the long shaft-like forms of implantable devices are easily placed in the organs with minimized outward protrusions via injection or insertion processes. Adding flexibility to the devices also enables effortless insertions through complex biological cavities, such as the cochlea, and enhances chronic reliability by complying with natural body movements, such as the heartbeat. Diverse types of such injectable implants developed for different organs are reviewed and the electronic, optoelectronic, piezoelectric, and microfluidic devices that enable stimulations and measurements of site-specific regions in the body are discussed. Noninvasive penetration strategies to deliver the miniscule devices are also considered. Finally, the challenges and future directions associated with deep body biomedical electronics are explained.

Spherical Lanczos Interpolation in Planar Projection or Format Conversions of Panoramic Videos

Panoramic videos provide users with an amazing experience with immersive and interactive viewing, and are now gaining global popularity. Since panoramic videos are spherical in nature while effectively processed in planar projection formats in applications, it is crucial to implement sphere-to-plane projection, where a good interpolation algorithm is of great importance regarding generating high quality planar perspective videos. Moreover, different planar projection formats adapt to different applications according to their own characteristics. It is common to convert one projection format to another, where interpolation algorithms also make a difference on performance. In this paper, an interpolation algorithm named spherical Lanczos (SLAN) is proposed to achieve advanced performance in sphere-to-plane projection or planar projection format conversions of panoramic videos. In SLAN, we fully consider panoramic videos are naturally spherical. Reference pixels are selected carefully, and the weights are calculated correctly. Experimental results demonstrate that the SLAN interpolation algorithm is beneficial for the whole processing chain of panoramic videos both with lossless compression coding and with loss compression coding in terms of the increase in various end-to-end PSNR and the decrease in BD_rate. The cubic projection (CBP) and adjusted cubemap projection (ACP) are also evaluated to illustrate that the proposed algorithm is applicable for all kinds of planar projection format due to their inevitable deformation.

Platform for Screening Abiotic/Biotic Interactions Using Indicator Displacement Assays.

This paper describes novel adaptations of optically sectioned planar format assays to screen compounds for their affinities to materials surfaces. The novel platform, which we name optically sectioned indicator displacement assays (O-IDA), makes use of displaceable dyes in a format adaptable to high-throughput multiwell plate technologies. We describe two approaches: the first being where the dye exhibits fluorescence in both the surface bound and unbound state and the second, where fluorescence is lost upon displacement of the dye from the surface. Half maximal inhibitory concentration (IC50), binding affinity (Ki), and binding free energy (ΔGads) values can be extracted from the raw data. Representative biomolecules were tested for interactions with silica in an aqueous environment and ZnO(0001)-Zn and (10-10) facets in a nonaqueous environment. We provide the first experimental values for both the binding of small molecules to silica and the facet-dependent ZnO binding affinity of key amino acids associated with ZnO-specific oligopeptides. The specific data will be invaluable to those studying interactions at interfaces both experimentally and computationally. O-IDA provides a general framework for the high-throughput screening of molecule binding to materials surfaces, which has important applications in drug delivery, (bio-) catalysis, biosensing, and biomaterial engineering.

Electrode, Electrolyte and Architecture Assessment for High Power Thin Film Microbatteries

Silicon integrated on-chip energy storage is an attractive goal for hybrid power sources coupled with energy harvesting for ‘Internet of Things’ devices and applications. Typical thin film microbatteries are limited to low power and energy outputs in the 2D planar formats. One of the issues with solid-state thin film microbatteries is the high resistance of the electrolyte which can lead to significant potential drop when powering devices during sensor operation and communication. The ability to provide high currents in a small form factor is a critical need for the development of realistic long life devices. In this work we will describe the use of Comsol finite element simulations to assess electrode materials, appropriate electrolytes and optimised architectures for improved microbattery power outputs. The simulations were of a microbattery stack where non-porous additive-free LiCoO2 is the cathode, lithium metal is the anode and solid-state, polymer, polymer-gel and liquid electrolytes were investigated. The simulations show the material utilisation and overall electrochemical cell behaviour of Li-ion electrode materials at typical and high power rates. Core-shell structures based on nanoarchitectures for electronic contact and active electrode materials have been investigated to improve power delivery for nanoscale active materials and for low conductivity oxide cathodes. The simulations indicate that the implementation of nanoarchitectures such as 3D and 3D core-shell nanoarchitectures when coupled with the appropriate electrolytes and interfacial reactions can have a significant advantage in terms of areal energy and power capabilities compared to a thin-film geometry for a microbattery cell. The deployment of these architectures for microbatteries where area is at a premium and high power capabilities are desirable should result in better performing hybrid energy and less complex power management systems. Acknowledgments The authors would like to acknowledge the financial support from Science Foundation Ireland (SFI) Grant number: 12/IP/1722, Nanomaterials design and fabrication for energy storage. This work is supported in part by a research grant from SFI co-funded by the European Regional Development Fund under Grant Number 13/RC/2077. This work is also supported in part by a research grant from the EU Horizon 2020 work programme – Enables, European Infrastructure Powering the Internet of Things, project number 730957.

A universal planar assay format for high sensitivity cytokine quantification in human serum and plasma

Abstract Quantifying prospective biomarkers of immune signaling in biological samples requires high assay sensitivity. The Simoa Planar Array provides greater sensitivity than ELISA, but has a finite assay menu. This study aimed to develop a universal ‘homebrew’ planar immunoassay format for development of high sensitivity assays for any analyte, by using an anchor antibody/peptide tag system to develop a universal capture plate. Anchor antibody specific for a peptide tag was microprinted in microwell plates. The peptide tag was conjugated to analyte-specific capture antibodies via maleimide chemistry, enabling high affinity binding of capture to anchor antibody. Bound sample antigen was sandwiched between the peptide-tagged capture and biotinylated detector antibodies; chemiluminescent detection was used to quantify signal. This ‘homebrew’ approach successfully detected sub picomolar levels of cytokines and chemokines in human or mouse serum and plasma, including IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-22, ITAC, MIP1a and MIP3b. When compared to commercially available planar assays the universal planar assay format provided comparable LLOQ and LOD with sample correlation (R2) >0.97 for all analytes tested. The universal planar assay was used to successfully screen multiple antibody pairs for human and mouse biomarkers and to develop robust assays using mouse, rabbit or goat monoclonal and polyclonal antibodies. This universal planar homebrew assay format combines the accuracy, reproducibility and high sensitivity of Simoa Planar Array technology with total analyte flexibility, and provides assay developers a simple and versatile method to rapidly develop robust high-sensitivity assays for any analyte of their choice.

Microfluidics in structured multimaterial fibers

Traditional fabrication techniques for microfluidic devices utilize a planar chip format that possesses limited control over the geometry of and materials placement around microchannel cross-sections. This imposes restrictions on the design of flow fields and external forces (electric, magnetic, piezoelectric, etc.) that can be imposed onto fluids and particles. Here we report a method of fabricating microfluidic channels with complex cross-sections. A scaled-up version of a microchannel is dimensionally reduced through a thermal drawing process, enabling the fabrication of meters-long microfluidic fibers with nonrectangular cross-sectional shapes, such as crosses, five-pointed stars, and crescents. In addition, by codrawing compatible materials, conductive domains can be integrated at arbitrary locations along channel walls. We validate this technology by studying unexplored regimes in hydrodynamic flow and by designing a high-throughput cell separation device. By enabling these degrees of freedom in microfluidic device design, fiber microfluidics provides a method to create microchannel designs that are inaccessible using planar techniques.

Optical trapping with planar silicon metalenses.

Contactless manipulation of micron-scale objects in a microfluidic environment is a key ingredient for a range of applications in the biosciences, including sorting, guiding, and analysis of cells and bacteria. Optical forces are powerful for this purpose but, typically, require bulky focusing elements to achieve the appropriate optical field gradients. To this end, realizing the focusing optics in a planar format would be very attractive and conducive to the integration of such microscale devices, either individually or as arrays. Here we report on, to the best of our knowledge, the first experimental demonstration of optical trapping using planar silicon metalenses illuminated with a collimated laser beam. The structures consist of high-contrast gratings with a locally varying period and duty cycle. They are designed to mimic parabolic reflectors with a numerical aperture of 0.56 at a vacuum wavelength of 1064nm. We achieve both two- and three-dimensional trapping in water, with the latter realized by omitting the central Fresnel zones. This Letter highlights the versatility of such lithographically defined metastructures for exerting optical forces without the need for traditional optical elements.

Multiplex immunoassays in endometriosis: An array of possibilities.

Multiplex immunoassays range from small-scaled multiplex sandwich ELISAs in a planar or bead-based format to the more expanded antibody arrays employing direct sample labeling. The plethora of data generated from these arrays could be of great interest to understand a complex disorder such as endometriosis. Multiplex immunoassay analysis may provide information on disease pathology and may lead to improved, timely diagnosis. Until now, the use of multiplex immunoassays has been limited in endometriosis. With the constant development of multiplex technologies, future studies should focus on implementing these techniques, and combining them with multivariate statistical analysis. In this review, we provide an overview of multiplex immunoassay methods used in endometriosis studies and the data sets acquired by these methodologies. These data and future studies might provide novel insights for biomarker discovery and investigation of the pathogenesis in endometriosis.

A Highly Stretchable Fiber‐Based Triboelectric Nanogenerator for Self‐Powered Wearable Electronics

The development of flexible and stretchable electronics has attracted intensive attention for their promising applications in next‐generation wearable functional devices. However, these stretchable devices that are made in a conventional planar format have largely hindered their development, especially in highly stretchable conditions. Herein, a novel type of highly stretchable, fiber‐based triboelectric nanogenerator (fiber‐like TENG) for power generation is developed. Owing to the advanced structural designs, including the fiber‐convolving fiber and the stretchable electrodes on elastic silicone rubber fiber, the fiber‐like TENG can be operated at stretching mode with high strains up to 70% and is demonstrated for a broad range of applications such as powering a commercial capacitor, LCD screen, digital watch/calculator, and self‐powered acceleration sensor. This work verifies the promising potential of a novel fiber‐based structure for both power generation and self‐powered sensing.

High-resolution, high-aspect-ratio iridium–nickel composite nanoimprint molds

Nanoimprint molds are traditionally made from silicon. Silicon molds suffer from distinct disadvantages as they are brittle, prone to damage, scratch easily, and can only be used in a planar format. This has limited their use in higher throughput systems where flexible molds are required such as in roll-to-roll and roll-to-plate systems. Nickel (Ni) molds, which are now de-rigueur in both batch and roller nanoimprint processes, can be used to address these problems, but fabrication and durability issues limit their availability and effectiveness in production. In this report, the authors introduce a fabrication route that has the potential to overcome the fabrication, quality, and wear problems of Ni molds. The new process relies on atomic layer deposition to form a smooth and high-aspect ratio patterned layer of iridium (Ir) on a Ni substrate. A large area nanohole array mold was fabricated using displacement Talbot lithography to demonstrate this process. The authors show the use of such composite molds via a batch thermal imprinting process to fabricate 70 nm hole arrays onto polycarbonate templates with a ±10% tolerance in diameter between the polycarbonate and the composite mold, and less than 1% of defects.