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Lecture

Contrast: Bright-Field Microscopy

In course

MICRO-561: Fundamentals of biomicroscopy

Introduction to the basic operational principles of the most commonly used optical microscopes such as widefield and fluorescence.
Introduction to essential microscopy components such as lenses, objectives, filters, cameras and light sources. ...

Description

This lecture covers the importance of contrast in microscopy, focusing on bright-field (wide-field) microscopy. It explains how contrast is essential to differentiate details from the background, especially when imaging transparent biological samples. The trade-off between contrast and resolution is discussed, along with techniques to enhance contrast, such as adjusting the contrast level and using staining methods. The historical significance of dyes in microscopy, particularly in histology, is also highlighted, showcasing how synthetic dyes revolutionized medicine by providing high-resolution contrast. The lecture delves into the contributions of scientists like Henry Perkin and Paul Ehrlich in the development of staining methods for histology.

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Instructors (2)

Arne Seitz

04/1996-06/2000 Scientific co-worker at Philipps-University of Marburg, Dep. of Physical Chemistry 07/2000-10/2002 Post Doc at Max-Planck Unit for Structural Molecular Biology in Hamburg 11/2002-11/2005 Post Doc at European Molecular Biolohy Laboratory (EMBL), Cell Biology and Cell Biophysics Programme 11/2005-03/2009 Staff Scientist at Advanced Light Microscopy Facility, EMBL 04/2009- Head of Bioimaging and Optics platforme (BIOP), Ecole Polytechnique Fédérale de Lausanne (EPFL)

Hatice Altug

2020-current Full Professor at the Institute of Bioengineering, EPFL, Switzerland2013-2020 Associate Professor (with tenure) at the Institute of Bioengineering, EPFL, Switzerland 2013 Associate Professor (with tenure) at Electrical and Computer Engineering Department of Boston University, USA 2007-2013 Assistant Professor (tenure-track) at Electrical and Computer Engineering Department of Boston University, USA 2007 Post-doctoral Fellow at Center for Engineering in Medicine of Harvard Medical School, USA 2000-2007 PhD. in Applied Physics at Stanford University, USA 1996-2000 B.S. in Physics at Bilkent University, Turkey

Official source

Ontological neighbourhood

Biology

Anatomy: Histology

Related concepts (18)

Microscopy

Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical, electron, and scanning probe microscopy, along with the emerging field of X-ray microscopy. Optical microscopy and electron microscopy involve the diffraction, reflection, or refraction of electromagnetic radiation/electron beams interacting with the specimen, and the collection of the scattered radiation or another signal in order to create an image.

Super-resolution microscopy

Super-resolution microscopy is a series of techniques in optical microscopy that allow such images to have resolutions higher than those imposed by the diffraction limit, which is due to the diffraction of light. Super-resolution imaging techniques rely on the near-field (photon-tunneling microscopy as well as those that use the Pendry Superlens and near field scanning optical microscopy) or on the far-field.

Staining

Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in the medical fields of histopathology, hematology, and cytopathology that focus on the study and diagnoses of diseases at the microscopic level. Stains may be used to define biological tissues (highlighting, for example, muscle fibers or connective tissue), cell populations (classifying different blood cells), or organelles within individual cells.

Bright-field microscopy

Bright-field microscopy (BF) is the simplest of all the optical microscopy illumination techniques. Sample illumination is transmitted (i.e., illuminated from below and observed from above) white light, and contrast in the sample is caused by attenuation of the transmitted light in dense areas of the sample. Bright-field microscopy is the simplest of a range of techniques used for illumination of samples in light microscopes, and its simplicity makes it a popular technique.

Phase-contrast microscopy

NOTOC Phase-contrast microscopy (PCM) is an optical microscopy technique that converts phase shifts in light passing through a transparent specimen to brightness changes in the image. Phase shifts themselves are invisible, but become visible when shown as brightness variations. When light waves travel through a medium other than a vacuum, interaction with the medium causes the wave amplitude and phase to change in a manner dependent on properties of the medium.

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