SPECTROstar Nano
Absorbance plate reader with cuvette port
What is a microplate reader?
A microplate reader is a laboratory instrument that is used to measure chemical, biological or physical reactions, properties, and analytes within the well of a microplate. A microplate consists of small multiple wells in which separated reactions take place, enabling the analysis of multiple samples. In the microplate, these reactions convert the presence of an analyte or the progression of biochemical processes into optical signals. The microplate reader is an optical system that detects these signals and thus quantifies the parameter of interest.
Scientists in the life sciences and pharmaceutical industries (e.g., drug discovery) strive to improve routine laboratory processes and efficiency by using products or instruments able to save time. A microplate reader can handle up to 3456 samples in minutes or even seconds. A plate reader helps to minimise operational time and to save reagent costs, allowing researchers to focus more on data analysis and the generation of actionable insights.
What is a microplate reader used for?
Microplate readers are used for the quantification of several biological and chemical assays in a microplate. Nowadays, the availability of a plethora of reagent kits enables the exploitation of multi-mode plate readers in different fields and for many different applications. Besides biological, cellular, biochemical, pharmaceutical research and drug discovery, both in academic and industrial environments, microplate readers are also used in drug discovery, environmental research, and in the food or cosmetics industry.
How do microplate readers work?
A microplate reader detects light signals produced within a specific wavelength range by samples that have been pipetted into a plate. The optical properties of these samples are the result of a biological, chemical, biochemical, or physical reaction. Different analytic reactions result in different optical changes used for analysis. Absorbance, fluorescence intensity, and luminescence are the most popular and most frequently used detected modes in laboratories worldwide. Additionally, advanced modes such as fluorescence polarization, time-resolved fluorescence, and AlphaScreen® are also available on multi-mode microplate readers.
Microplate-based measurements detect light signals produced by a sample, converted by a sample, or transmitted through a sample. In the plate reader, the signal is measured by a detector, usually a photomultiplier tube (PMT). PMTs convert photons into electricity that is then quantified by the microplate reader. The output of this process is numbers by which a sample is quantified and that are used for data analysis.
Depending on the nature of the optical signals and consequently on the measurement mode, microplate samples may need to be excited by light at specific wavelengths. This light source is usually a broadband xenon flash lamp. To allow specific excitation of the sample, the light produced by the lamp is selected by specific excitation monochromator or filter-based optics. On microplate readers, for increased sensitivity and specificity, the optical system can employ filters or monochromators on the emission side to select emission wavelengths. These are usually placed between the sample and the detector. The optical system combined with the PMT determines the wavelength range of the reader.
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Determine the assays you want to run
When you start evaluating plate readers, your core applications are usually already defined. It is still worth revisiting them carefully to choose a single- or multimode reader that is robust and future-proof.
Most labs need to run basic assays such as nucleic acid and protein quantification, reporter gene assays for gene expression analysis, and cell viability tests. For each of these, multiple kits and chemistries exist, based on different principles, technologies, and sensitivity levels, so you should know in advance the exact kit name and supplier you plan to use on your reader.
Beyond routine assays, thousands of tests can address specific biological questions, and some may offer simpler microplate-based alternatives to the cumbersome workflows you currently rely on. Reviewing your day-to-day lab work and asking colleagues how they use microplate readers is a key step before purchasing a new instrument.
You can also explore our “research areas” for practical ideas on how a microplate reader can streamline your experiments.
Choosing detection modes for your assay
Different assay kits are detected differently, even though they might answer the same biological question. If you already identified commercial kits, you will find the required measurement mode in the product insert. Otherwise, a microplate reader can include one of the following modes or a combination thereof for multi-mode readers:
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![Icon Absorbance]()
Absorbance
Absorbance measures how much light is lost (absorbed) when transmitted through a sample. Molecules often absorb light at a specific wavelength and can be quantified by measuring their absorbance. Wavelength selection capability in the UV-visible range is mandatory on an absorbance reader and can be achieved with filters, monochromators or spectrometers. Typical applications that are read by an absorbance microplate reader are:
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![Icon Fluorescence Intensity]()
Fluorescence intensity (incl. FRET)
Fluorescence is the absorption of light energy and its transformation into emission light, next to kinetic energy and heat. Since the emitted light is lower in energy than the input light, emission is always of higher wavelength. The process of energy uptake, energy conversion and light emission is quick and occurs in a nanosecond timeframe. The measurement of fluorescence intensity occurs as follows in a plate reader: excitation with light at a specific wavelength and quantification of the emission light at higher one at about the same time. The wavelength selection is accomplished via filters or monochromators. The signal intensity is linear to the concentration of a fluorophore and is accordingly used to quantify fluorescent (or fluorescently labelled) molecules. Other applications employ a shift in emission or an increase of fluorescence when interacting with a molecule of interest. Typical applications detected by a fluorescence plate reader are the following:
Cell viability assays Resazurin assay, Calcein-AM Aggregation assays Thioflavin T (RT-QuIC) Enzyme activity assays 4-methylumbelliferone (4-MU), NADH-based assays, 7-Amino-4-Methylcoumarin (AMC) Reactive oxygen species H2DCFDA assay, DCF assay Nucleic acid quantification Qubit assays, Quant-iT assays (e.g. PicoGreen) -
![Icon Luminescence]()
Luminescence (incl. BRET)
The emission of light without prior excitation is referred to as luminescence. Its production in life science experiments occurs as the result of a chemical reaction and is either spontaneous or needs enzymatic catalysis. In a spontaneous reaction, the substrate as well as co-factors need to be present to generate light. For an enzyme-dependent luminescence reaction, a functional enzyme is essential. Such an enzyme is called luciferase. A detector is necessary to detect the emitted light on a plate reader. Typically, all light coming from a well is bundled by a lens and guided to the detector. Accordingly, a luminescence plate reader does not rely on filters or on an excitation source. For dual emission approaches, the wavelength selection is accomplished via filters or monochromators. This very sensitive mode is used to study the following:
Cell viability assays CellTiterGlo Reporter assays Dual luciferase reporter assay Receptor-ligand-binding BRET-based assays -
![Icon Fluorescence Polarization]()
Fluorescence polarization
Fluorescence polarization is a fluorescence-based technology that uses polarized light to excite the fluorescent molecule. The change of polarization of the emitted light is determined by measuring the emission in the parallel and perpendicular plane relative to the excitation polarization plane. Changes in polarization result from differences in molecular weight. Small and light molecules move quickly and depolarize fluorescence emission whereas bigger molecules move slowly and retain polarization. This principle allows to study the following:
Competitive binding assays Nucleotide detection to report on enzyme activities Transcreener assays -
![Icon AlphaScreen]()
AlphaScreen
AlphaScreen (Amplified Luminescent Proximity Homogeneous Assay) technology uses beads that release singlet oxygen when excited with red light (680 nm). Singlet oxygen molecules move up to 200 nm and react with thioxene in a chemiluminescent reaction. Further energy transfers lead either to broad signals between 520 and 620 nm or to discrete signals. If donor beads (singlet oxygen releasing) and acceptor beads are in close proximity, a luminescent signal is emitted and can be detected by the reader. These beads are usually brought together by antibodies that specifically bind to the same analyte, or that are coupled to molecules that interact with each other. On a plate reader, excitation at 680 nm is combined with a readout that is delayed in time, compared to the excitation. It is often used for high-throughput screening applications studying the following:
Protein, cytokine quantification AlphaLISA assays Protein phosphorylations Alpha SureFire assays Protein-protein interactions AlphaScreen assays -
![Icon Nephelometry]()
Nephelometry
Nephelometry is a technique used to measure the amount of turbidity in a solution caused by the presence of suspended insoluble particles. When directed through a solution containing suspended solid particles, light is transmitted, absorbed, and scattered (reflected off the particles). Nephelometry directly quantifies the intensity of the light scattered by insoluble particles in the sample. A nephelometer is a reader that contains a light source, a detector arranged at a right angle to the light beam, and in between an optical light scattering collector. This principle allows to study the following:
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![Icon time-resolved Fluorescence]()
Time-resolved fluorescence
Time-resolved fluorescence (TRF) is a method based on fluorescence that requires excitation of the sample at a specific wavelength and detection at a different one. Compared to conventional fluorescence intensity, the emission endures for a millisecond instead of a nanosecond timeframe. This is made possible by lanthanides, rare earths with long-lifetime fluorescence characteristics. Readers measure the emission signal with a delay to the excitation, avoiding the detection of background and autofluorescence. TRF is employed for these applications:
Metabolic assays soluble probes for extracellular acidification and oxygen consumption measurements Biomolecule and protein quantification Immunoassay, DELFIA -
![Icon TR-FRET]()
TR-FRET
Time-Resolved FRET (TR-FRET) is a detection technology that combines TRF with Förster´s Resonance Energy Transfer (FRET). It is mainly used to analyse binding events and for high-throughput drug screening. FRET describes a transfer of energy between two fluorophores. The transfer depends on the spatial proximity between donor and acceptor and on the overlap between the donor´s emission and the acceptor´s excitation spectrum. Kits include HTRF, Lanthascreen, Transcreener and THUNDER, and are employed for these applications:
Binding studies TR-FRET-based assays
Our single-mode plate readers
Single-mode microplate readers measure only one detection technology, such as absorbance. They are most suitable when the instrument will be dedicated to a single long-term application, for example nucleic acid detection. Long-running assays often occupy the reader for days, so one mode is usually sufficient. Typical use cases include microbial growth monitoring over one or more days and fluorescence-based thioflavin T assays that may run for up to a week.
If all planned workflows rely on one detection technology, a single-mode reader will usually meet laboratory needs. With an absorbance microplate spectrophotometer, for instance, you can measure enzyme activity, DNA and protein concentration, cell health and viability, microbial growth, and many other absorbance-based assays. The trade-off is reduced access to higher-sensitivity or more specific assays that require other detection modes.
When current plans involve only one mode but future assay requirements are uncertain, consider a microplate reader that can be upgraded later to a multimode configuration.
LUMIstar Omega
Dedicated microplate luminometer
SPECTROstar Omega
Absorbance plate reader with ultrafast UV/vis spetcrometer
NEPHELOstar Plus
Microplate nephelometer for light-scattering and turbidity measurements
Our multi-mode microplate readers
Multi-mode microplate readers can measure two or more detection technologies. They typically support absorbance, luminescence, and fluorescence assays, giving access to a wider range of kits and applications.
This flexibility is useful when many users share the same instrument, when assay requirements vary from project to project, or when you already know you need to run assays based on different detection modes. A single multi-mode reader is also usually more cost-effective than buying several dedicated single-mode instruments.
PHERAstar FSX
Powerful and most sensitive HTS plate reader
CLARIOstar Plus
Most flexible plate reader for assay development
VANTAstar
Flexible microplate reader with simplified workflows
Omega Series
Upgradeable multi-mode microplate reader series
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6 up to 96 well plates
Up to 96-well formats typically provide strong signals that are straightforward to detect, and full plates can be read in a relatively short time by most microplate readers. High sensitivity and fast acquisition are still important for these formats when you need to capture rapid kinetics, such as calcium flux assays, or low-amplitude signal changes in biosensor applications.
Image ©Greiner Bio-One GmbH
Image ©Greiner Bio-One GmbH
384 well plates
With 384-well plates, plate reader speed and sensitivity become critical. For fluorescence assays, a focusing system helps boost sensitivity. For luminescence, readers designed to minimize cross-talk are recommended, because the closely spaced wells increase the risk of signal spilling into neighbouring wells.
Image ©Greiner Bio-One GmbH
Image ©Greiner Bio-One GmbH
1536 and 3456 well plates
These very dense plate formats use only small microliter volumes (typically below 10 µl), so they require dedicated microplate readers. The instrument must provide precise plate positioning, high read speed, and high sensitivity to capture very small signals in the shortest possible time.
Image ©Greiner Bio-One GmbH
Image ©Greiner Bio-One GmbH
LVis Plate
The LVis plate is designed for absorbance measurements in small volumes, for example nucleic acid detection. It is commonly used to determine nucleic acid and protein concentrations.
This plate provides 16 measurement spots, each loaded with 2 µl of sample for subsequent absorbance reads. It is transparent in the UV range and compatible with all BMG LABTECH microplate readers.
This plate provides 16 measurement spots, each loaded with 2 µl of sample for subsequent absorbance reads. It is transparent in the UV range and compatible with all BMG LABTECH microplate readers.
Atmospheric Control Unit
Enhanced cell-based assays
Evaluation Plate
Functional Microplate Reader Validation
Filters
Filters for a wide range of applications
LVis Plate
Low-volume measurements
Microplate Stacker
Microplate handling system
THERMOstar
Intelligent microplate incubation
What’s my budget?
When it comes to the purchase of a microplate reader, budget of course plays a role.
The price of a microplate reader depends on the technical equipment and the number of measurement technologies that the device can measure in case of a multimode microplate reader. The price range of a reader starts at 2.500 Euro/Dollars for a basic filter-based ELISA microplate reader and could go up to over 150.000 Euro/Dollars for a high-end multi-mode microplate reader with several detection modes and the best technology for highest sensitivity and fastest detection.
Be careful with your choice and do not only consider your current, but also your future plate reader needs.
Keep an eye on the possibility to upgrade your microplate reader with additional features or measurement modes. If you have the chance to upgrade later, you don’t need to buy an additional microplate reader for future applications. This saves not only money and useful space in your lab, but also time that you need to get used to a new plate reader or brand.
Besides the hardware, consider the software as well. Is it included with the reader? Is it easy to use with user-programmable protocols? Do you have to pay for additional user licenses? Is data analysis software included?
Be also aware of possible additional hidden costs that could come with your microplate reader e.g., fees for servicing, support, updates or bundled reagent packages.
Also keep in mind that although filter-based readers are usually cheaper than monochromator-based instruments, you need to purchase different filters for different applications. Be sure to factor in those costs as well.
Why choose a BMG LABTECH plate reader?
BMG LABTECH is specialised in the production of microplate readers only and has more than 35 years of full expertise in microplate reading technology. This knowledge translates in the experimental results that our instruments deliver - the only factor that counts in your lab! Our users can trust to receive best results in sensitivity, speed, dynamic range and flexibility. Moreover, our microplate readers are developed to provide optimum assay performance for years. Our microplate readers are developed, produced and tested in Germany and are built to be extremely robust and reliable.
One quality seal is our product ranking on the established scientific platform "Select Science", where our customers gave us 4.7 out of 5.0 stars. Don't miss to read what our users have to say about our microplate readers.
Buy only what you need
Due to their modularity, all our microplate readers can be equipped with different modes and cover a multitude of applications. Additional features can be upgraded. This gives you the chance to keep your options open, even if you don’t use the full scope of your microplate reader right at the bat.
All-round service and support
At BMG LABTECH we strive to provide you with the very best customer service. If you need customer support, we are only a phone call or email away. During business hours, you immediately speak live to a person who is happy to assist. There is no automated phone system or waiting in a queue, our scientists, engineers, and technicians are always there to help.
Multi-user integrated software package
All our instruments come with a multi-user software package that includes a microplate reader control and a data analysis software. It can be installed on as many computers as users require, without the need to purchase licenses, and is conceived to meet the FDA 21 CFR Part 11 guidelines for data integrity. Software updates for our microplate readers are of no charge within the first 12 months after purchase.