Microplate readers are staple instruments for any researcher conducting biological research. These analytical instruments are spectrophotometers that measure the light absorbance, fluorescence or luminescence of samples in multi-well microplates. In microplates, reactions convert the presence of an analyte or the progression of biochemical processes into optical signals. As an optical system, the microplate reader then detects these signals and quantifies the parameter of interest.
Modern laboratories face increasing pressure to deliver high-quality data across a wide range of assay types—often with limited resources, evolving workflows and growing complexity in experimental design. In contrast to single cuvette measurements, plate readers enable the high throughput analysis of many samples per run, improving the productivity and reproducibility of experiments.
For decades, microplate readers have empowered life science researchers to advance protein and cell biology, breaking the barriers to novel, landmark discoveries. And as technology advances, so too do microplate readers as versatile solutions for both routine and complex biological investigations.
Flexible detection modes
There are three common detection modes for plate readers— absorbance, fluorescence and luminescence. Absorbance in the ultraviolet to visible range is often used to quantify analytes, such as proteins, nucleic acids and small molecules. Absorbance plate readers are designed for this purpose and are well-suited for routine colorimetric assays. Using monochromator‑ or filter‑based excitation with a lamp (and a hybrid optical system on iD5e), fluorescence-enabled readers shine light at samples within microplates to detect the intensity of light emitted. The resulting signals are processed to quantify the amount of analytes within the sample. These types of plate readers are essential when carrying out assays, such as in ELISAs (typically colorimetric), cell viability and proliferation assays, quantitation of fluorescent labels, and more Lastly, luminescence-enabled readers, which detect and measure luminescence, are suited for applications such as luciferase reporter assays, bioluminescence resonance energy transfer (BRET), and flash and glow luminescent assays.
While absorbance, fluorescence and luminescence are traditionally the most common, some laboratories need more functionality. Multimode plate readers address this challenge by offering flexible detection capabilities. For example, Molecular Devices’ SpectraMax iD5e provides five detection modes—absorbance, fluorescence, luminescence, time‑resolved fluorescence (TRF), and fluorescence polarization (FP)—plus optional expansions including TR‑FRET (including HTRF), BRET, bottom‑read luminescence, and Western blot detection The plate reader also boasts a hybrid optical system that combines monochromator and filter-based detection for enhanced sensitivity and dynamic range.
Ever-evolving research demands
Research laboratories are ever-evolving. From personnel and goals to the actual instrumentation, equipment and consumables, needs, demands and technologies change. That’s why the SpectraMax iD Series—including models iD3s and iD5e—has an upgradeable design that allows labs to start with a core system and expand capabilities as research needs evolve. The SpectraMax iD3s is a streamlined three‑mode reader designed for simplicity and value, while the SpectraMax iD5e is an enhanced five‑mode reader with hybrid optics for increased research capabilities.
These multimode readers support live-cell workflows, including environmental control (CO₂/O₂). The optional gas mixer and advanced shaking features allow researchers to maintain ideal conditions for cell viability, proliferation and biomarker response assays. The company’s SmartInject Technology also ensures complete reagent mixing in every well for high-performance flash assays, minimizing dead volume and maximizing precision.
The SpectraMax iD Series comes with SoftMax Pro Software, the most published and cited microplate reader software globally. Within the software, more than 200 preconfigured protocols are available for a wide variety of common assays, enabling seamless, user-friendly integration of data acquisition and analysis.