Multifocal imaging for precise, label-free tracking of fast biological processes in 3D

AbstractMany biological processes happen on a nano- to millimeter scale and within milliseconds. Established methods such as confocal microscopy are suitable for precise 3D recordings but lack the temporal or spatial resolution to resolve fast 3D processes and require labeled samples. Multifocal imaging (MFI) allows high-speed 3D imaging but is limited by the compromise between high spatial resolution and large field-of-view (FOV), and the requirement for bright fluorescent labels. Here, we provide an open-source 3D reconstruction algorithm for multi-focal images that allows using MFI for fast, precise, label-free tracking spherical and filamentous structures in a large FOV and across a high depth. We characterize fluid flow and flagellar beating of human and sea urchin sperm with a z-precision of 0.15 µm, in a volume of 240 × 260 × 21 µm, and at high speed (500 Hz). The sampling volume allowed to follow sperm trajectories while simultaneously recording their flagellar beat. Our MFI concept is cost-effective, can be easily implemented, and does not rely on object labeling, which renders it broadly applicable.

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Multifocal imaging for precise, label-free tracking of fast biological processes in 3D

10.1101/2020.05.16.099390 ◽

2020 ◽

Author(s):

Jan N. Hansen ◽

An Gong ◽

Dagmar Wachten ◽

René Pascal ◽

Alex Turpin ◽

...

Keyword(s):

Spatial Resolution ◽

High Speed ◽

Reconstruction Algorithm ◽

Cost Effective ◽

Human Sperm ◽

Dark Field ◽

Biological Processes ◽

Label Free ◽

Flagellar Beat ◽

Dark Field Microscopy

AbstractMany biological processes happen on a nano- to millimeter scale and within milliseconds. Established methods such as confocal microscopy are suitable for precise 3D recordings but lack the temporal or spatial resolution to resolve fast 3D processes and require labeled samples. Multifocal imaging (MFI) allows high-speed 3D imaging but suffers from the compromise between spatial resolution and field-of-view (FOV), requiring bright fluorescent labels and limiting its application. Here, we present a new approach for high-resolution, label-free, high-speed MFI, based on dark-field microscopy and operative over large volumes. We introduce a 3D reconstruction algorithm that increases resolution and depth of the sampled volume without compromising speed and FOV. This allowed us to characterize the flagellar beat of human sperm and surrounding fluid flow with a precision below the Abbe limit, in a large volume, and at high speed. Our MFI concept is cost-effective, can be easily built, and does not rely on object labeling, making it broadly applicable.

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Scanning x-ray fluorescence microscopy and principal component analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133394 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1752-1753

Author(s):

Brian Cross

Keyword(s):

Principal Component Analysis ◽

Fluorescence Microscopy ◽

Spatial Resolution ◽

High Speed ◽

Image Acquisition ◽

Principal Component ◽

Fluorescence Microscope ◽

Acquisition Rate ◽

X Ray ◽

Speed Up

A relatively new entry, in the field of microscopy, is the Scanning X-Ray Fluorescence Microscope (SXRFM). Using this type of instrument (e.g. Kevex Omicron X-ray Microprobe), one can obtain multiple elemental x-ray images, from the analysis of materials which show heterogeneity. The SXRFM obtains images by collimating an x-ray beam (e.g. 100 μm diameter), and then scanning the sample with a high-speed x-y stage. To speed up the image acquisition, data is acquired "on-the-fly" by slew-scanning the stage along the x-axis, like a TV or SEM scan. To reduce the overhead from "fly-back," the images can be acquired by bi-directional scanning of the x-axis. This results in very little overhead with the re-positioning of the sample stage. The image acquisition rate is dominated by the x-ray acquisition rate. Therefore, the total x-ray image acquisition rate, using the SXRFM, is very comparable to an SEM. Although the x-ray spatial resolution of the SXRFM is worse than an SEM (say 100 vs. 2 μm), there are several other advantages.

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Doppler global velocimetry for 50 kHz, large field of view measurement of high-speed flows

AIAA Scitech 2021 Forum ◽

10.2514/6.2021-0119 ◽

2021 ◽

Author(s):

Ashley J. Saltzman ◽

Kevin T. Lowe ◽

Wing F. Ng

Keyword(s):

High Speed ◽

Field Of View ◽

Large Field ◽

High Speed Flows

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The Radio Probe™: A New Measurement Tool for High Speed Integrated Circuits

ISTFA 2005: Conference Proceedings from the 31st International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2005p0224 ◽

2005 ◽

Author(s):

Mark Kimball

Keyword(s):

Integrated Circuits ◽

Integrated Circuit ◽

High Speed ◽

Attenuation Factor ◽

Cost Effective ◽

Frequency Measurement ◽

Single Frequency ◽

Measurement Tool ◽

Probe Design ◽

Differential Measurement

Abstract This article presents a novel tool designed to allow circuit node measurements in a radio frequency (RF) integrated circuit. The discussion covers RF circuit problems; provides details on the Radio Probe design, which achieves an input impedance of 50Kohms and an overall attenuation factor of 0 dB; and describes signal to noise issues in the output signal, along with their improvement techniques. This cost-effective solution incorporates features that make it well suited to the task of differential measurement of circuit nodes within an RF IC. The Radio Probe concept offers a number of advantages compared to active probes. It is a single frequency measurement tool, so it complements, rather than replaces, active probes.

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Infrared Emission Spectroscopy as a Reliability Tool

ISTFA 1999: Conference Proceedings from the 25th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa1999p0077 ◽

1999 ◽

Author(s):

Q. Kim ◽

S. Kayali

Keyword(s):

Spatial Resolution ◽

Emission Spectroscopy ◽

Hot Spot ◽

Cost Effective ◽

Infrared Emission ◽

Test System ◽

Operating Conditions ◽

Yield Enhancement ◽

Infrared Emission Spectroscopy ◽

Channel Temperature

Abstract In this paper, we report on a non-destructive technique, based on IR emission spectroscopy, for measuring the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). A submicron-size He-Ne laser provides the local excitation of the gate channel and the emitted photons are collected by a spectrophotometer. Given the state of our experimental test system, we estimate a spectral resolution of approximately 0.1 Angstroms and a spatial resolution of approximately 0.9 μm, which is up to 100 times finer spatial resolution than can be obtained using the best available passive IR systems. The temperature resolution (<0.02 K/μm in our case) is dependent upon the spectrometer used and can be further improved. This novel technique can be used to estimate device lifetimes for critical applications and measure the channel temperature of devices under actual operating conditions. Another potential use is cost-effective prescreening for determining the 'hot spot' channel temperature of devices under normal operating conditions, which can further improve device design, yield enhancement, and reliable operation. Results are shown for both a powered and unpowered MESFET, demonstrating the strength of our infrared emission spectroscopy technique as a reliability tool.

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Быстродействующая атомно-силовая и сканирующая капиллярная микроскопия в решении задач материаловедения, биологии и медицины

Nanoindustry Russia ◽

10.22184/1993-8578.2020.13.3-4.222.228 ◽

2020 ◽

Vol 13 (3-4) ◽

pp. 222-228

Author(s):

И.В. Яминский ◽

А.И. Ахметова

Keyword(s):

Antibiotic Resistance ◽

Early Detection ◽

Biomedical Research ◽

Drug Screening ◽

Targeted Delivery ◽

High Speed ◽

Scanning Probe ◽

Biological Processes ◽

Atomic Force ◽

Probe Microscope

Разработка высокоэффективных режимов быстродействующего сканирующего зондового микроскопа, в первую очередь атомно-силовой и сканирующей капиллярной микроскопии, представляет особый интерес для успешного проведения биомедицинских исследований: изучения биологических процессов и морфологии биополимеров, определения антибиотикорезистентности бактерий, адресной доставки биомакромолекул, скринингу лекарств, раннему обнаружению биологических агентов (вирусов и бактерий) и др. The development of highly efficient modes of a high-speed scanning probe microscope, primarily atomic force and scanning capillary microscopy, is of particular interest for successful biomedical research: studying biological processes and the morphology of biopolymers, determining antibiotic resistance of bacteria, targeted delivery of biomacromolecules, drug screening, early detection agents (viruses and bacteria), etc.

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2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators

Nature Communications ◽

10.1038/s41467-021-20926-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Hitesh Agarwal ◽

Bernat Terrés ◽

Lorenzo Orsini ◽

Alberto Montanaro ◽

Vito Sorianello ◽

...

Keyword(s):

Boron Nitride ◽

Hafnium Oxide ◽

High Speed ◽

Hexagonal Boron Nitride ◽

Temperature Stability ◽

Cost Effective ◽

Fold Increase ◽

Building Blocks ◽

High Quality ◽

New Device

AbstractElectro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs.

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Utilising Commercially Fabricated Printed Circuit Boards as an Electrochemical Biosensing Platform

Micromachines ◽

10.3390/mi12070793 ◽

2021 ◽

Vol 12 (7) ◽

pp. 793

Author(s):

Uroš Zupančič ◽

Joshua Rainbow ◽

Pedro Estrela ◽

Despina Moschou

Keyword(s):

Printed Circuit Boards ◽

Electrochemical Sensors ◽

Cost Effective ◽

Electrochemical Sensing ◽

Label Free ◽

Circuit Boards ◽

Printed Circuit ◽

Sensing Applications ◽

Electrochemical Biosensing ◽

Pre Treatment

Printed circuit boards (PCBs) offer a promising platform for the development of electronics-assisted biomedical diagnostic sensors and microsystems. The long-standing industrial basis offers distinctive advantages for cost-effective, reproducible, and easily integrated sample-in-answer-out diagnostic microsystems. Nonetheless, the commercial techniques used in the fabrication of PCBs produce various contaminants potentially degrading severely their stability and repeatability in electrochemical sensing applications. Herein, we analyse for the first time such critical technological considerations, allowing the exploitation of commercial PCB platforms as reliable electrochemical sensing platforms. The presented electrochemical and physical characterisation data reveal clear evidence of both organic and inorganic sensing electrode surface contaminants, which can be removed using various pre-cleaning techniques. We demonstrate that, following such pre-treatment rules, PCB-based electrodes can be reliably fabricated for sensitive electrochemical biosensors. Herein, we demonstrate the applicability of the methodology both for labelled protein (procalcitonin) and label-free nucleic acid (E. coli-specific DNA) biomarker quantification, with observed limits of detection (LoD) of 2 pM and 110 pM, respectively. The proposed optimisation of surface pre-treatment is critical in the development of robust and sensitive PCB-based electrochemical sensors for both clinical and environmental diagnostics and monitoring applications.

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Plasma enhanced label-free immunoassay for alpha-fetoprotein based on a U-bend fiber-optic LSPR biosensor

RSC Advances ◽

10.1039/c5ra02910d ◽

2015 ◽

Vol 5 (31) ◽

pp. 23990-23998 ◽

Cited By ~ 37

Author(s):

Gaoling Liang ◽

Zhongjun Zhao ◽

Yin Wei ◽

Kunping Liu ◽

Wenqian Hou ◽

...

Keyword(s):

Surface Plasmon Resonance ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Localized Surface Plasmon Resonance ◽

Fiber Optic ◽

Cost Effective ◽

Alpha Fetoprotein ◽

Localized Surface Plasmon ◽

Label Free

A simple, label-free and cost-effective localized surface plasmon resonance (LSPR) immunosensing method was developed for detection of alpha-fetoprotein (AFP).

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