what does microplate reader measure
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Published On: March 29th, 2022Categories: Articles, Microplate

Microplate readers measure changes in biochemical, cellular or physical properties in the wells of a plate. Microplate readers are designed for a standard 96 well plate, but there are some plate readers available for other plate sizes. As lab automation increases, adherence to a standard microplate size is critical so that automated systems can handle the plates.

Microplates were originally developed in the 1950s, but it wasn’t until the advent of lab robotics equipment in the 1980s and 1990s that these plates became standardized. Wondering what a microplate reader measures?

What does a Microplate Reader measure?

A microplate reader predominately measures ultra-violet or visible absorbance, luminescence, and fluorescence. Absorbance is the measurement of how the substance in each well absorbs light in a given wavelength.

Luminescence is the measurement of how much light is emitted by the substance in each well. Fluorescence is also a measurement of emitted light when exposed to a fluorescence light source. The source wavelength is slightly different then the emitted light, allowing the emitted light to be measured separately from the source.

Single-mode microplate readers can only measure 1 of these characteristics, while multimode microplate readers can measure three or more modes. A multimode microplate reader will facilitate research without taking up a large benchtop footprint if a lab has a wide range of assays to run.

How does a it work?

A microplate reader is a spectrophotometer that uses a limited range of wavelengths. Microplate readers shine a light source through a filter or a monochromator, then the filtered beam is directed to the plate. Light passes vertically through the pate wells, hitting a detector that transmits information about the wavelengths in the sample to a computer.

It’s important to make sure that the same amount of liquid is in each well, because microplate readers use the path length that light travels through to calculate each measurement. If one well is more full than another, the microplate reading might not be accurate. For this reason, most labs use microplate readers in conjunction with automated liquid handling systems.

What are the applications?

Applications vary depending on the microplate measurement in question. In general, microplate readers are excellent tools for protein-related assays. Microplates are famous for ELISA assays, but there are applications for all three measurement types.

A microplate reader measures the three qualities of absorption, luminescence, and fluorescence.

The most common absorbance applications are protein quantification, including ELISA, DNA or RNA quantification, and Bradford assays. Luminescence is useful in a wide range of assays, including cell viability, cytotoxicity, protein interaction via BRET, and enzymatic reaction assays. Finally, fluorescence measurements can be used for protein interaction via FRET, flux and signaling, and gene expression assays.

What is a Microplate Handling System?

A microplate handling system is a lab automation tool that can help access, stack, and store microplates. These systems usually feature a robotic arm that gently moves plates between storage areas and microplate readers. A microplate handling system can work with liquid handling equipment, barcode labels and scanners, incubators, and plate washers.

How do the optical systems in microplate readers adapt to varying assay requirements, especially in multimode readers that handle absorbance, luminescence, and fluorescence?

The optical systems in microplate readers are marvels of engineering, designed to be as adaptable as they are precise. In multimode readers, this adaptability is achieved through a combination of sophisticated filters, monochromators, and detection technologies. Filters allow for the selection of specific wavelengths of light suitable for different assays, while monochromators offer the flexibility to dial in on an exact wavelength needed for a particular measurement. This versatility ensures that whether a researcher is measuring absorbance, luminescence, or fluorescence, the reader can adjust to the specific optical requirements of each assay, providing accurate and reliable results across a wide spectrum of research applications.

What advancements have been made in microplate reader technology to enhance sensitivity and specificity, particularly for low-abundance analytes or in assays with high background noise?

To tackle the challenges of detecting low-abundance analytes and managing assays with high background noise, microplate reader technology has made significant leaps forward. Advances in optical design, such as the use of more sensitive photomultiplier tubes for luminescence detection and charge-coupled device (CCD) cameras for fluorescence, have dramatically increased the sensitivity of microplate readers. Additionally, software algorithms have become more sophisticated, able to discern between signal and noise with greater accuracy. Innovations in well design, including the development of microplates with enhanced light-gathering capabilities, further amplify the signal from low-abundance analytes, ensuring that even the most subtle of changes can be detected and quantified.

How are microplate readers being integrated into automated lab systems, and what challenges arise in ensuring compatibility across different platforms and equipment?

The integration of microplate readers into automated lab systems represents a convergence of functionality and efficiency. This process involves leveraging open communication standards and modular design principles, allowing microplate readers to seamlessly communicate with other lab automation tools, such as liquid handlers, robotic arms, and software management systems. However, challenges in ensuring compatibility include the need for standardized data formats and interfaces that can operate across different manufacturers’ platforms. Overcoming these challenges requires ongoing collaboration between equipment providers, as well as the development of more universal standards for lab automation. As these integration efforts advance, they pave the way for more streamlined, efficient, and error-free workflows within the laboratory environment.

By addressing these expert-level questions, we gain a deeper appreciation for the technological intricacies and advancements that underpin microplate reader technology and its role in the modern automated laboratory landscape.

Contact Hudson Robotics to request a quote, choose a microplate handling system, or learn about other lab automation tools.