Dark Field Microscopy
Dark Field Microscopy - Related Videos
04:43
Antibody Conjugated Nanoparticle-based Quantification Using Dark Field Microscopy: A Procedure to Capture and Quantify Specific Exosomes from Body Fluids
0 Views •
2023
This video describes the use of low-magnification, dark-field microscopy to quantify specific exosomes in small volume biofluidic samples. The exosomes thus identified can serve as potential cancer biomarkers.
01:29
Dark Triad and Person Perception
0 Views •
2025
Person perception is influenced by both external behaviors and the observer’s internal characteristics, including personality traits. Individuals with dark personality traits, comprising psychopathy, Machiavellianism, and narcissism — collectively known as the dark triad – exhibit manipulative and exploitative tendencies in social contexts. These traits affect how they perceive others and how they are perceived.The Role of Dark Personality Traits in Person PerceptionBlack et al. (2014) explored...
06:42
Wide-field Fluorescent Microscopy and Fluorescent Imaging Flow Cytometry on a Cell-phone
0 Views •
Cited by 32 •
2013
We review our recent results on the integration of fluorescent microscopy and imaging flow cytometry tools on a cell-phone using compact and cost-effective opto-fluidic attachments. These cell-phone based micro-analysis devices might be useful for cytometric analysis, such as performing various cell counting tasks as well as for high-throughput screening of e.g., water samples in resource limited settings.
04:45
Light-Dark Preference Test: A Method to Study Anxiety-Related Behavior in Zebrafish
0 Views •
2023
The video describes the light-dark preference assay to study the anxiety-related behavior in zebrafish following the exposure to ethanol.
FAQs
The central stop changes which light reaches the objective. Direct illumination is excluded, while oblique rays encounter the specimen and are redirected by scattering into the lens. This optical separation suppresses the uninterrupted background contribution and makes scattered light from specimen regions visually prominent, providing contrast for otherwise difficult-to-see biological material.
Brightness depends on how strongly each region scatters the oblique illumination. Features that redirect more of this light toward the objective become more luminous, whereas regions producing little scattering remain less visible against the dark field. This relationship makes contrast useful for distinguishing structures without relying on an added stain.
Dark Field Microscopy provides a contrast pattern that differs from conventional transmitted-light imaging. Bright structures stand out when specimen regions scatter oblique rays, which can reveal transparent or unstained material that provides limited detail in other approaches. Using these methods together can give researchers complementary information about morphology and observable behavior.
Avoiding fixation and staining allows researchers to examine living biological material in a more direct state. This approach can preserve motility and other visible behaviors while reducing artifacts introduced during preparation. It is therefore useful when the goal is to assess both specimen appearance and activity rather than morphology after processing.
The arrangement must prevent direct illumination from entering the objective while directing oblique rays toward the specimen. A central stop produces this separation, and the objective receives light only after the specimen scatters it. Observing the resulting image depends on maintaining this relationship between illumination, specimen, scattering, and lens.
The method is suited to examining microorganisms, cell structures, and motility when specimens are transparent or unstained. It can show morphological features while also allowing researchers to observe movement in living samples. These capabilities make it relevant for studies where preparation should preserve biological behavior and minimize alteration of the specimen.
It is especially useful when conventional transmitted-light imaging provides limited detail for transparent or unstained material. The technique can increase the visual prominence of regions that scatter oblique light, helping researchers assess morphology or behavior without adding a staining step. Its value is greatest when preserving living samples and reducing preparation artifacts matters.