History of the Microscope

What is Microscopy?

Microscopy is the art of seeing. It’s the exploration of what’s not naturally visible to the human eye. There are myriad processes and instruments to make a specimen more apparent and detailed images rendered. In the end, microscopy is the exploration of the architecture of the cellular level, sub-cellular components, even down to the molecular level. Interestingly, the word microscope is derived from Ancient Greek—”mikros” small “skopein” to look/see.

The type of microscopy used most often is optical microscopy, which relies on visible light and an arrangement of lenses to render an image of a small sample in an enlarged fashion. There are two kinds of optical microscopy: simple and compound. A simple microscope contains one lens, similar to a traditional magnifying glass. A compound microscope contains multiple lenses—one close to the specimen (objective) and one for the viewing person (eyepiece).

Therefore, compound microscopes are more powerful for viewing cellular tissue and even small, living specimens. But that was then and this was not yet. No electron microscopy existed yet. An electron microscope uses beams of electrons instead of light to visualize the specimen. In other words, it sees much more than the light microscope. There are two forms of electron microscopes. The first is Transmission Electron Microscopy (TEM), which transmits electrons through the specimen—which must be very thin—and the resultant image reveals the internal properties and structures.

The second is Scanning Electron Microscope (SEM), which scans a concentrated beam of electrons across the specimen’s surface—which results in a more intricate three-dimensional image of topography. Another significant subcategory is scanning probe microscopy, which features Atomic Force Microscopy and Scanning Tunneling Microscopy. Scanning probe techniques operate by using a physical probe that traverses the surface of a specimen to create a mapped image of the specimen’s composition. For instance, AFM employs a probe that assesses its adhesive properties with the sample surface to create highly accurate images.

STM utilizes its probe to assess the tunneling current generated from the probe and specimen, permitting evaluations of conductive specimens at the atomic scale. Microscopy is utilized across many fields of science. For example, biology, microbiology, and medicine utilize microscopy to understand the anatomy and physiology of life—from cellular components to histological slides and vaccine slide assessment. Materials science uses microscopy to differentiate between crystalline and amorphous states of elements and compounds. Chemistry uses it to study semiconductors, while nanotechnology uses it to see and access nanoscopic particles and components, which can then be manipulated for additional study. Microscopy is the future of many fields.

For instance, new techniques in microscopy are burgeoning daily. Super-resolution microscopy and cryo-electron microscopy are cutting-edge developments in microscopy. Super-resolution microscopy enables scientists to visualize objects below the visible light diffraction limit, meaning it can see down to the nanometer range. Thus, items that one would assume are invisible to the naked eye—or potentially an electron microscope—can come into the viewable range. Cryo-electron microscopy instantly freezes the sample it examines, meaning researchers can view the sample in situ and assess biomolecular parts with extensive granularity.

Ultimately, microscopy is a fundamental scientific and technological advancement that investigates a minuscule world and reveals an even more extensive one. From the different types of microscopy to its uses and applications, the technique has transformed fields for years and continues to help humanity understand more about what’s in its environment and the more extensive natural design.

History of Microscope

The history of the microscope is a lineage of progress—from glass to today’s revolutionary tools. The microscope timeline is as follows:

• 1st Century AD: Glass is perfected by the Romans into rudimentary lenses for magnifying.
• 13th Century: Eyeglasses are created by Italians, foreshadowing the later developments of magnifying.
• 1600s: The first known microscope was created in Holland in 1590 by spectacle makers Hans and Zacharias Janssen, who placed several lenses in a tube to view smaller items at larger scales. The origin of the microscope came from Galileo Galilei, who purportedly took a telescope and inverted it to see smaller items at larger scales.
• 1665: Robert Hooke published in Micrographia his findings, which included microscope-generated pictures, and he was the first to call something a “cell” after viewing the composition of cork.
• 1674: Anton van Leeuwenhoek becomes the first human to ever see a unicellular organism (he dubbed them “animalcules”) and document it through a rudimentary simple microscope.
• 1825: Joseph Jackson Lister contributes to the development of microscope lenses by eliminating chromatic aberration.
• 1860s: The Abbe sine condition, relative to the formula of optical systems, is determined by Ernst Abbe, permitting better optical design.
• 1931: The first transmission electron microscope (TEM) is created by Ernst Ruska and Max Knoll, which uses an electron beam instead of light, generating greater magnification and resolution.
• 1953: Frits Zernike won the Nobel Prize in Physics for the phase-contrast microscope that allowed for the viewing of transparent specimens without staining.
• 1981: The scanning tunneling microscope (STM) was invented by Gerd Binnig and Heinrich Rohrer, which allowed for the imaging of surfaces at atomic resolution.
• 1986: The atomic force microscope (AFM) was patented by Binnig, Quate, and Gerber, which allows operators to see images of surfaces at nanometer resolution.
• 1988: The first three-dimensional atom probe was invented by Alfred Cerezo, Terence Godfrey, and George D.W. Smith, which could chemically identify singular atoms and map them in three-dimensional reconstruction.
• 1992: Douglas Prasher clones the gene for green fluorescent protein, enabling this marker to serve as a fluorescent tag for later biological experimentation.
• 2014: The Nobel Prize in Chemistry awarded to Eric Betzig, Stefan W. Hell, and William E. Moerner for their research on super-resolved fluorescence microscopy that enables nanometer scale imaging beyond the diffraction of light.
• 2024: Image processing and data analysis of microscopy via AI and machine learning decreased exponentially, opening up the potential for quicker developments.

Types of Microscope

Here are some of the most common microscopes and what they do:

1. Light Microscope—uses visible light to magnify samples; common in many laboratories for general study.
2. Compound Microscope—uses a group of lenses to magnify very small objects; common in studies of biological samples.
3. Stereo Microscope (Dissecting Microscope)—provides three-dimensional (3D) image; common in the study of larger samples and dissection.
4. Electron Microscope (EM)—uses a beam of electrons to magnify objects at ultra-high levels; common to observe cells and cell structures.
5. Transmission Electron Microscope (TEM)—sends electrons through a specimen to study internal structure.
6. Scanning Electron Microscope (SEM)—sends electrons across the surface of a specimen to study external structures. Electron Microscope 3D imaging. Creates 3D images by scanning samples with electrons.
7. Confocal Microscope- Scans using lasers and optics to create high-resolution images of deeper samples.
8. Fluorescence Microscope- Creates images using fluorescence. Used to visualize internal structures in cells—an important part of biological research.
9. Atomic Force Microscope (AFM)- Scans surfaces using a probe at the level of atoms.
10. Polarizing Microscope- Uses polarized light to examine a sample. Common in geology and materials science.

Importance of Microscope

• Helps observe structures invisible to the naked eye.
• Essential for biology, medicine, and material science studies.
• Allows detailed study of cells, bacteria, and tissues.
• Supports disease diagnosis and drug development processes.
• Aids in forensic investigations and solving crimes.
• Used for quality control in various industries.
• Encourages scientific discoveries and technological advancements.