QIAxpert System

High system linearity for best results

QIAxpert exhibits excellent linearity and assures accurate and reliable quantifications. To assess the linearity of the system, pure gDNA was serially diluted to generate samples from 2000 to 2 ng (see figure Exceptional linearity of QIAxpert). The resulting dilutions were then measured on the QIAxpert using 2 µl for each of 5 replicates. The quantifications from the QIAxpert were plotted against the known concentration values, and the resulting plot demonstrates the exceptional linearity (with a regression coefficient of >0.999) of QIAxpert up to 2000 ng/ml or 40 OD (A₂₆₀, 10 mm path length).
 

Proven reproducibility of measurements

To demonstrate the reproducibility of measurements with the QIAxpert, 10 ultrapure dsDNA samples were repeatedly quantified with the instrument. The sample concentrations spanned the complete dynamic range of the system and each sample was measured 10 times. Standard deviation (SD) and coefficient of variation (CV) were calculated to illustrate the minimal variability from sample to sample. Results from 6 representative samples are shown (see table below).
 

High reproducibility of measurements across complete dynamic range

	Sample 1	Sample 2	Sample 3	Sample 4	Sample 5	Sample 6
Mean (µl/ml)	1949.4	961.6	475.9	92.7	45.0	2.7
SD	6.5	3.1	1.6	0.2	0.8	0.2
CV (%)	0.33	0.32	0.33	0.258	1.72	7.57

Flexibility and accuracy with QIAxpert Slides

QIAxpert uses disposable microfluidic slides to analyze up to 16 samples per run. On-board capillary intake and storage channels ensure easy sample loading with no cross-contamination, and allow unused positions to be used in later analyses. The capillary channels preserve samples and prevent evaporation (see figure Microfluidic features of the QIAxpert Slide). Thus, samples can be loaded and left at room temperature for up to 2 hours prior to readout. Constructed from advanced technical plastics that allow high optical transmission over the full UV/VIS spectrum, QIAxpert Slides enable highly accurate readings from just 2 µl of sample.
 

Smart analysis protocols based on cutting-edge bioinformatics

The QIAxpert performs classic nucleic acid and protein quantification based on absorbance measurements. In addition, smart analysis protocols called “apps” come pre-installed to quantify specific analytes of interest. Based on top bioinformatics expertise and extensive sample testing, the spectral profiling protocols let users focus on the molecule of interest, subtracting other absorbing impurities and background turbidity.
 

Unique spectral content profiling

To addresss challenging research samples, such as difficult-to-isolate or amplified nucleic acids, unique spectral protocols accurately quantify complex samples containing multiple UV/VIS absorbing chemicals that interfere with classical absorbance methods. Intelligent software algorithms extract from the measured UV/VIS spectrum the contributions of specific components like DNA, RNA, and impurities (see figure RNA spectral profiling analysis). The quantity of these components is then calculated. These data are very helpful to analyses such as quantitative gene expression by qPCR, where quality of purified RNA is crucial because gDNA contamination leads to decreased accuracy of results.

It just takes a few simple steps to load samples into the QIAxpert and have the results delivered on-screen and in exportable format. Simply pipet 2 µl of each sample for up to 16 samples onto a QIAxpert Slide. Once loaded, samples can be held in the microfluidic capillaries of the QIAxpert Slide for up to 2 hours. This lets users batch samples and minimize the time spent at the instrument. Samples are measured immediately upon inserting the QIAxpert Slide into the instrument. Additional information and settings can be entered while QIAxpert reads the samples, thereby saving time. The readout of 16 samples is completed within 2 minutes and results are displayed directly on the integrated screen. Quantification of nucleic acids and proteins can be done by traditional absorbance readings (A₂₆₀ or A₂₈₀) or using unique spectral content profiling protocols that hone in on the molecule of interest. Data are easily exported to a USB stick or networked device. A report can also be printed or displayed on a smartphone or tablet by scanning a displayed QR code.

Fast results with the intuitive QIAxpert Software

QIAxpert features a full-color integrated touchscreen interface, so no extra computer is required. The intuitive and easy-to-use QIAxpert Software was designed to fit a busy lab schedule. Beyond UV/VIS quantification at 260 and 280 nm wavelengths, QIAxpert Software performs spectral decomposition to selectively quantify DNA, RNA, or protein in a sample. Experiment setup is quick and easy, and can be defined while the instrument reads samples. Results are available as comprehensive data reports in HTML format that can be opened in any browser. Additionally, tabular data are available in CSV and .txt formats (see figure Flexible report options to meet your needs). To facilitate data analysis and sharing, the data are exportable to a USB stick, a networked drive, or a smart device via a QR code.