Forensic DNA typing

Forensic science plays a crucial role in our legal system with life-changing decisions often based on forensic data. It is a unique scientific discipline that faces unique challenges. Forensic samples are often the most difficult specimens to process. They are typically limited in quality and quantity, can be environmentally exposed, and may require purification from difficult substrates that contain PCR inhibitors. Extensive sample preparation is also required with DNA analysis. Obtaining accurate results from difficult samples is one of many everyday challenges in forensics. Forensic scientists also face intense regulatory requirements, increasing throughput demands and limited resources.

Preparation

Preparation

In forensic DNA analysis, the primary material can come from a vast variety of sources and brings along a lot of unique challenges. No single molecule can be waisted lighthearted, no potential source of contamination can be uncared for.

  • Pipettes and tips
    • Automatic Combitip recognition: Eliminates time consuming volume calculations, avoiding incorrect dispensing volumes
    • Ergonomic one-button tip ejector: For one handed operation and contact-free Combitips advanced ejection
    • Speed Adjustment: Program aspiration and dispensing speed for the utmost in precision and accuracy while also preventing splashing
    • Repetitive dispensing modes: Decrease the number of movements for the user by allowing them to fill the tip once and dispense up to 100 times without a refill
    • Wide dispensing range: 1 μL to 50 mL provides up to 5,000 dispensing volumes with increments as low as 100 nanoliters
  • Tubes and plates
    • Hinged Eppendorf Safe-Lock lid prevents unintentional lid opening during incubation and storage
    • Polypropylene provides high resistance to chemicals, mechanical stress and temperature extremes
    • Manufactured without the use of slip agents, plasticizers, and biocides – substances that have been shown to leach from plastic consumables into the sample and negatively affect bio-assay results
    • g-Safe®: Exceptional centrifugation stability up to 30,000 x g prevents sample loss due to tube breakage and provides extra safety when working with hazardous samples
    • Precise lid sealing for minimal evaporation rates during long-term storage
  • Centrifuges
    • Aerosol-tight Eppendorf QuickLock® caps and lids allow fast and ergonomic lid locking
    • Automatic rotor recognition and imbalance detection for maximum operational safety
    • Plate rotor options for centrifugation of all types of MTP, PCR or deepwell plates
    • Fixed-angle rotors for high-speed molecular biology applications in tubes from 0.2 mL to 85 mL
    • High centrifugation speed of up to 22,132 × g (14,000 rpm)
  • Thermo mixing devices
    • Heating, mixing and cooling in all common vessel and plate formats from 5 µL to 50 mL
    • Increased mixing frequency up to 3,000 rpm (depending on the SmartBlock used)
    • Excellent mixing performance due to unique 2DMix-Control technology
    • Anti-spill technology prevents lid wetting and cross-contamination
    • Reliable prevention of condensate formation with the Eppendorf ThermoTop (condens.protect®)
Extraction and purification

Extraction and purification

DNA needs to be extracted and purifi ed before it can go into analysis. This step is especially crucial — if DNA is lost or a bias for certain DNA regions occurs, it can never be corrected in the following steps. Also, PCR inhibitors need to be separated here to guarantee powerful amplifi cation of the target DNA and to avoid false-negative results.

  • Centrifuges
    • Max. rotor capacity: 24 x 1.5/2.0 mL vessels
    • Max. speed: 20,238 × g (14,680 rpm)
    • OptiBowl® design for quiet operation, even without a rotor lid
    • Soft-touch one-finger lid closure for ergonomic operation
    • SOFT brake to protect sensitive samples
  • Pipettes and tips
    • The unique one-button operation offers a fast and ergonomic handling with reduced operating effort and active aerosol reduction. To avoid an accidential tip ejection a clear haptic feedback is provided.
    • The spring loaded tip cone improves user to user reproducibility and improved ergonomics by lowering tip attachment force
    • The Reference 2 multi channel offers a high flexibility incl a spring-loaded tip cone which can be switched on/off optionally
    • The secondary adjustment supports the easy adjustment of your Reference 2 for the most accurate pipetting of different liquids or other external conditions without the need for a full calibration.
    • The quick lock enables an easy cleaning and maintenance of your pipette.
  • Tubes and plates
    • LoBind material guarantees maximum sample recovery for improved assay results
    • Free of surface coating (e.g. silicone) to minimize the risk of sample interference
    • Lot-tested and certified free of human DNA, DNAase, RNase and PCR inhibitors (PCR clean)
    • Available in tube, microplate, and deepwell plate formats for easy-up scaling
    • Unique OptiTrack® matrix: up to 30 % faster sample identification and fewer pipetting errors
  • Automation
    • Same as 5075t, plus
    • Combination of magnetic finger module and Eppendorf ThermoMixer®
    • Dedicated MagSep reagent kits for nucleic acid purification form 1–24 samples
    • 3 x Prep assistants for user guided automation of nucleic acid purification with MagSep kits
    • 4 x PCR assistants to streamline PCR set-up workflow
Quantification and analysis

Quantification and analysis

Only a reliable analysis of your DNA concentration and integrity allows you start the following steps with the correct concentrations. This analysis will not only show the quality of your DNA sample, it will also show the quality of the previous steps.

  • Photometers
    • UV/Vis spectral range 200 nm to 830 nm
    • Freely selectable wavelengths across the entire UV/Vis spectral range (increment: 1 nm)
    • Compatible with microliter measuring cells and standard cuvettes
    • Temperature controlled cuvette shaft in the BioSpectrometer kinetic (20 °C to 42 °C in 0.1 °C increments)
    • Fluorescence intensity measurements across a range of 0.5 nM to 2,000 nM fluorescein with the BioSpectrometer fluorescence
  • Cuvettes
    • Suitable for measuring small volumes (≥50 µL)
    • UV and Vis-transparent between 220 nm and 1,600 nm
    • Two built-in optical path lengths in a single cuvette-just turn the UVette 90° to change from 10 mm and 2 mm
    • Volume markings for 500 µL and 1,000 µL
    • Available in individually packaged PCR clean and protein-free quality
  • Microvolume cuvette
    • Microvolume measuring cell for measuring 1.5 - 10 µL sample volumes
    • Low self-absorption (≤0.05 A @ 260 nm)
    • Hydrophobic surface coating on quartz glass for precise formation and positioning of the sample volume
    • Simple cleaning to minimize the risk of sample carry-over
    • A defined angle for folding the sides of the cuvette quarantees reproducible handling
  • Reader plates
    • UV-VIS microplates feature an ultrathin film bottom for excellent light transmission in the UV range
    • Black Microplates offer an excellent signal-to-noise ratio - for clear signals even with low-concentration samples
    • White Eppendorf Microplates are optimized for highest sensitivity in the detection of luminescence signals by maximizing reflection
    • Solid black and white assay plates are made of polypropylene resulting in high resistance to chemicals, mechanical stress and temperature extremes
    • All plates are optimized for minimal autofluorescence and autoluminescenc
Amplification and detection

Amplification and detection

The power of PCR with its logarythmic amplifi cation is still unbeaten in forensic DNA profiling. A reliable amplifi cation of the relevant DNA fragments is a prerequisite for the genotyping of the sample. Getting these results quickly can be crucial in forensic laboratories.

  • Thermocyclers
    • Intuitive graphic programming
    • Small footprint
    • Universal block for ultimate flexibility
    • Connect up to 2 Mastercycler nexus eco to your existing unit
    • Available with gradient
  • PCR consumables
    • One-piece design: combining a polycarbonate frame and polypropylene wells for optimum performance
    • Extremely thin-walled polypropylene wells guarantee optimum heat transfer to the sample
    • Exceptionally solid and torque-resistant polycarbonate frame
    • Improved well-to-well tolerance
    • Cut-away corner and alphanumeric grid-referencing
  • Photometers
    • Fixed wavelengths at 230 nm, 260 nm, 280 nm, 320 nm, 340 nm, 405 nm, 490 nm, 562 nm, 595 nm and 600 nm
    • Display of purity scan for specific applications
    • Preprogrammed applications for quick start
    • Integrated application and results memory
    • Data transfer via USB interface
  • Microvolume cuvette
    • Microvolume measuring cell for measuring 1.5 - 10 µL sample volumes
    • Low self-absorption (≤0.05 A @ 260 nm)
    • Hydrophobic surface coating on quartz glass for precise formation and positioning of the sample volume
    • Simple cleaning to minimize the risk of sample carry-over
    • A defined angle for folding the sides of the cuvette quarantees reproducible handling
Storage

Storage

To be available for future reevaluation, more and more samples will be stored over a longer period of time. More freezer capacity is needed and samples need to be stored at defined conditions, maybe for decades to come!

  • Freezers
    • Capacity: 570L
    • Occupies 102.5 x 85.2 cm of floor space
    • Consumes only 11.8 kWh/day (Freezer set to -80°C)       
    • Ambient to -85°C pull down is 5.2 hours
    • Holds up to 40,000 samples
  • Concentrator
    • Comes in 3 system configurations
    • Extremely quite operation <50 dB(A)
    • Chemical-resistant, maintenance-free PTFE diaphragm pump eliminates the need for changing pump oil
    • Small footprint saves valuable bench space
    • Wide variety of 15 different rotor options to accommodate tubes from 0.2 mL to 50 mL, microplates and PCR plates
  • Freezer boxes
    • Transparent lid for easy and fast sample inspection combined with 5 writing areas for a flexible labeling
    • High quality polypropylene ensures an excellent dimensional stability
    • Flexible and high-contrast labeling on the light colored box
    • Reliable sample reference through permanent laser-labeld alphanumeric marking of each location
  • Deepewell plates
    • OptiTrack® matrix: up to 30 % faster sample identification and fewer pipetting errors via high-contrast alphanumeric labeling
    • Conical RecoverMax® well design: Optimized well geometry for maximum sample recovery and excellent mixing properties
    • Minimal remaining volume and high uniformity from well to well
    • Raised well rims and smooth surface for reliable closing, even with heat sealing
    • Easy and reliable stacking