The dotLab mX System uses a novel, flow based Diffractive Optics Technology (dot®) to combine multiplex immunoassay formats with real time measurements into protein interactions. The result is a highly flexible, easy to use and low cost platform that can provide more informative immunoassays compared to traditional end-point techniques. Together these features are designed to address the growing needs of biomedical researchers for running routine, multiplex assays on a variety of biological samples. With the dotLab mX System, researchers will have the abilities to qualify reagents during immunoassay development, develop novel diagnostic tests, or investigate disease biomarkers for potential clinical applications – easily and quickly on a single platform.
For more information on the dotLab mX System, please download our latest brochure.
dotLab mX System Features:
- Provides real time observations of binding and dissociation reactions allowing for immediate understanding of molecular events and the development of immunoassays
- Detects analyte concentrations across a broad dynamic range (approximately 7 logs) through sequential signal amplification techniques, allowing the measurement of picomolar and micromolar target levels in the same sample
- Flexible multiplex capabilities allowing researchers to customize the platform to their own molecular targets of interest
- Ideal for complex biological samples such as serum, plasma or crude cell lysates with only a minimal level of sample preparation
- A single platform suitable for all stages of development from reagent qualification to routine analysis
- User friendly and intuitive software for data processing and quantitation that is available with support for 21 CFR Part11 Compliance
- Provides rapid assay results (15-90 minutes) allowing researchers the ability to make same-day decisions
- Costs per test comparable to traditional assay methods (eg. ELISA) and lower capital costs compared to other advanced systems
Diffractive Optics Technology
Diffractive optics technology, or “dot®”, brings together two well-understood technologies: grating-based light diffraction and immobilized capture surfaces. This combination produces a sensitive and very simple technique for the detection of molecular binding and dissociation events without the use of fluorescent labels.
Capture molecules, such as antibodies, are immobilized on an ordered pattern of lines that form a diffraction grating on the surface of the prism-shaped dotLab® Sensor (Figure 1). The sensor surface forms the base of a low volume flow cell. A series of discrete diffraction beams is generated when the patterned molecules are illuminated with a laser. Binding of biomolecules, such as an antigen, to the patterned capture molecules increases the height of the surface pattern, producing an increased phase shift in the reflected beams, which in turn increases diffraction signal intensity that is detected in real time by a photodiode detector below the sensor. Dissociation of the interacting species with a competitive reagent conversely leads to a measurable decrease in signal.
Since the illumination occurs through an integrated optical prism, the laser beam does not pass though the bulk solution in the flow channel. This significantly reduces the effects of sample refractive index and color on signal intensity which allows for the direct analysis of crude biological samples. This property also allows for the use of vigorous mixing or changes in reagent flow during an assay without signal disruption.
Figure 1. Surface binding produces phase shifts that increases the diffraction signal intensity
For more information on diffractive optics technology, download our technology brochure（http://www.axelabiosensors.com/docs/literatures/22.dot_brochure.pdf）
dotLab Sensors
Assay Spots
Core to the technology is the use of disposable polystyrene sensors each consisting of a contiguous array of interaction surfaces or spots lining the bottom of a 10 µL flow channel. The spots are composed of a coupling reagent pre-patterned in a repetitive sequence of lines forming a diffraction grating (Figure 2). Several attachment chemistries (eg: avidin, amine reactive, oligonucleotide-based addressing reagents for multiplexing) allow the user flexibility in coupling their own content to the sensors.
Figure 2: A schematic representation of a dotLab sensor showing the contiguous arrangement of interaction spots lining the bottom of a flow channel. Pre-patterned coupling reagent on each spot forms a diffraction grating which is used to monitor molecular interactions in real-time.
The dotLab mX System introduces samples and assay reagents onto the sensor using an automated sampling system and high-precision fluidic controller. An integral prism allows continuous interrogation of the pattern from below to create the diffraction signal without interference from the sample matrix. As molecules bind to the sensor surface, the real time signal responds in proportion to molecular size and concentration
The dot® - Avidin Sensor
The dot® - Avidin Sensor is pre-patterned with avidin and utilizes the robust biotin-avidin interaction to rapidly immobilize biotinylated capture reagents.
Features:
- Low cost per test compared to traditional immunoassay techniques
- Requires only a few microliters of sample required for analysis
- Compatible with dotReady reagents or choose from thousands of readily available commercial biotinylated reagents
- Allows for easy conversion of plate based avidin or streptavidin immunoassays to the dotLab 's real time format
The dot® - Covalent Sensor
The dot® - Covalent Sensor utilize a carboxylic acid surface that can be covalently coupled to protein amino groups using carbodiimide chemistry. In the linking procedure, the surface carboxyl groups first are activated and stabilized by reaction with EDC and sulfo-NHS. The activated groups subsequently react with the amines on the capture protein to form stable covalent amide linkages.
Features:
- Directly links capture species covalently, providing an excellent alternative when commercially biotinylated reagents are not available, or when quantities of protein samples are insufficient for offline conjugation
- Lidless sensor design makes sample recovery possible for further offline analysis (eg. mass spectrometry)
Multiplex Sensors for Real Time Immunoassays
The new panelPlus™ Sensors gives developers of protein assays the ability to easily create their own customized multiplex panels. Using Axela’s panelPlus™ Labeling Kits, researchers can incorporate specific protein targets of their choice onto discrete locations on a single sensor making it easier to directly compare different protein biomarkers during the same assay. This unique flexibility in panel design is combined with the dotLab’s real time observation feature which eliminates typical restrictions associated with most endpoint multiplex assays (eg. the requirement to optimize each reaction to the same time point).
How it Works
The figure below illustrates the essential features of the panelPlus™ Sensor. Each assay location within the sensor is pre-patterned with a unique oligonucleotide-addressing reagent. Capture reagents are labeled with the complementary oligonucleotide sequence. When introduced to the sensors, the capture reagents rapidly hybridize to their location without cross reacting to other spots. Simple conjugation kits allow users to address their own affinity reagents as required. This approach gives complete flexibility in designing panels. The use of sequential amplification techniques on the dotLab enables the analysis of a wide variation of analyte concentrations in a single sample, thereby eliminating the need for serial dilutions on multiple assays. The panelPlus™ Sensors are also designed to be easily regenerated using proprietary buffers which dissociates the oligonucleotide-conjugated capture reagent from its complementary strand, creating a fresh surface for subsequent reagent immobilization.
Figure 3 – An illustration of the five steps that enable customizable multiplexing on the panelPlus™ dotLab Sensor"
System Software
- Mac OS based, user friendly software for method creation, data gathering and data analysis
- Integrated bar code scanner for sensor and sample entry
- Features a straight forward, ‘Drag and Drop’ interface for creating customized methods for sensor washing/conditioning and sample loading, as well as sample schedules for multiple runs
- Can be programmed for up to 4 dotLab Sensors on a single instrument
- Live Run Screen allows monitoring of experiments in real time
- Generates data reports quickly and automatically
- Easy to use data analysis kit includes tools for generating calibrating curves and for determining relative rates of binding or dissociation
- Available with support for 21 CFR Part 11 FDA Compliance
