No. 51 – 2019 New Pipetting System: 384. Ready. Set. Pipette! (BN 51) JULY 2019 PAGE 1 Is That Really DNA in Your Tube? Comparative Analysis of UV-Absorbing Leachables in Micro-Test Tubes RAFAL GRZESKOWIAK AND DIANA HÜBLER, EPPENDORF AG, HAMBURG Abstract 40 °C, 24 h Bioactive contaminants leaching out of laboratory consum- ables (leachables) may significantly affect experiments and may pose a likely source of error in many assay systems. Non autoclaved 2.08 Autoclaved Recent scientific evidence provides numerous examples of 2.0 biological assays, which have been shown to be affected by leachables, including routine applications such as spectro- > The next level: Eppendorf Conical Tubes 25 mL photometric measurements of nucleic acids. This study 1.67 provides a comparative analysis of UV-absorbing leachables and 1.5 resulting false DNA readings 1.41 upon incubation of water sam- ples in 1.5 mL micro-test tubes from several manufacturers. 1.07 0.98 0.97 A majority of tubes tested (see 1.0 0.95 0.91 Fig. 1 and 2) showed high to 0.87 0.82 0.78 DNA-Concentration in µg/mL in DNA-Concentration very high false DNA concentra- 0.73 tions, as opposed to tubes from 0.59 Eppendorf. 0.57 NGS sample preparation: why automation is worth it > 0.51 0.5 Introduction Increasing scientific evidence shows that chemical substances 0.23 0.18 0.17 leaching out of plastic consumables (leachables) may signifi- 0.16 0.14 cantly affect experiments and pose a likely source of error in 0.06 0.05 many assay systems [1, 2, 3, 4]. These include not only various 0 a Fi Si Gr Sa enzymatic [1, 2, 3], receptor binding [1, 5], cell culture [3, 6], Ax Bz Bx Co Vw W and high-end analytical assays [7], but also common labora- tory procedures such as spectrophotometric measurements Eppendorf of nucleic acids [8]. Fig. 1: False DNA concentration (μg/mL) based on UV-absorbing leachables, which had Digitize your −80 °C treasures! been released from micro test tubes into ultra¬pure water samples after incubation at > In the latter case, the UV-absorbing leachables lead to false 40 °C, 24 h. Mean values of 24 pooled samples from non-autoclaved (brown bars) and positive readings and may hamper various downstream appli- autoclaved (blue bars) tubes are shown. cations, which rely on accurate DNA/RNA measurements, Results and discussion such as PCR, qPCR, sequencing, and NGS, as well as forensic and microarray applications. In this study, we performed a Fig. 1 shows that even under relatively mild temperature comparative analysis of UV-absorbing leachables and result- conditions, the majority of micro-test tubes may release ing false DNA readings of water samples incubated in 1.5 mL considerable amounts of UV-absorbing contaminants, which micro-test tubes from several manufacturers. The majority in turn will lead to false DNA readings (up to 1.1 μg/mL of of tubes tested showed high to very high false DNA concen- false dsDNA), and that this process can be dramatically en- trations, with the exception of Eppendorf Tubes®. hanced by autoclaving (up to 2.1 μg/mL of false dsDNA). The increase of leaching after autoclaving was highest for Materials and methods the following manufacturers: Wa (6.4 fold), Bx (5.6 fold), Application Notes Eppendorf Safe-Lock Tubes and standard 1.5 mL micro-test Ax (5.3 fold), Co (3.6 fold), Si (4.4 fold), and Gr (3.5 fold). tubes of ten other manufacturers (24 tubes for each manu- In contrast, measurements derived from samples incubated facturer) were filled with 1.5 mL of ultra-pure water and in Eppendorf Safe-Lock Tubes, non-autoclaved as well as incubated at 95 °C, 30 min or at 40 °C, 24 hours (as indicated autoclaved, resulted in very low values: 0.05 μg/mL and in the results section). Incubations were performed with 0.06 μg/mL, respectively. autoclaved (120 °C, 20 min, 10 bar) and non-autoclaved tubes. This considerable increase of leaching after autoclaving in Samples for each individual manufacturer were pooled and tubes of most manufacturers may be due to different molecu- spectrophotometric measurements were performed using lar/chemical compositions of polymers used, which may be Comparative analysis of UV-absorbing leachables in micro test tubes · Production of the Eppendorf BioSpectrometer® and UVette®. Absorbance more prone to alteration or damage during the autoclaving at 260 nm and the factor 50 µg/mL were used to calculate process, and lead to increased release of the polymerization the false DNA concentration derived from UV-absorbing by-products and/or additives used during the production leachables for each sample. process. ® Your local distributor: www.eppendorf.com/contact hiPSC-derived cortical neurospheres in the DASbox Mini Bioreactor System · etc. Eppendorf AG · Barkhausenweg 1 · 22339 Hamburg · Germany · E-mail: [email protected] · www.eppendorf.com 2 EDITORIAL · DEAR READERS Imprint Publisher Eppendorf AG, Barkhausenweg 1, 22339 Hamburg, Germany Telephone: +49 40-53801-0 Fax: +49 40-53801-556 E-mail: [email protected] www.eppendorf.com/bionews Editorial team Berrit Hoff (Editor-in-Chief), Dr. Hanaë König, Dr. Tanja Musiol, Natascha Weiß Design Holger Paulsen Grafik-Design, Hamburg, Germany Printed by Dear Readers, Gebr. Klingenberg & Rompel in Hamburg GmbH, Hamburg, Germany Do you enjoy pipetting into 384-well-plates? We have asked users in the lab and Image references their unanimous opinion is that manual pipetting in this format is time-consuming All images Eppendorf AG. Exceptions: and cumbersome. Do the tips fit? Will I manage to fill the plate without making a Application Note p. 4, Fig. 2A: TissUse mistake? Will I be able to concentrate sufficiently on 384 tiny wells? Forget about GmbH; Application Note p. 8, Fig. 1: these worries; from now on manual pipetting into 384-well plates is child’s play. Embryotools; p. 24: Science /AAAS With our new pipetting system, one minute is all you need to fill a 384-well plate in an effortless, safe, and reproducible manner. Read more on pages 4 – 6. Important notes We welcome all readers’ articles for this News from the world of Eppendorf Tubes®: Eppendorf Tubes 5.0 mL, which have been publication. However, no responsibility is successfully introduced some time ago, are now also available amber-colored for light- accepted for unsolicited manuscripts. The sensitive samples and as DNA LoBind or Protein LoBind tubes for maximum sample new products described may be launched recovery. Additionally, we are now also taking the field of conical tubes to the next at different times in various countries. level by launching the new Eppendorf Conical Tubes 25 mL. This new type of tube Please contact your local Eppendorf bridges the gap within the traditional conical tubes of 15 mL and 50 mL. Available with organization or distributor for details. either screw cap or innovative, patented snap cap, the Eppendorf Conical Tubes 25 mL offer tangible benefits such as efficient contamination prevention, excellent growth of Technical specifications subject to change. bacteria, less plastic waste, and space-saving storage. More on page 8. Errors and omissions excepted. As we all know, it’s sometimes the small things that make a big impact! Try our new Eppendorf worldwide bioprocess accessories for improved handling (page 13). www.eppendorf.com/contact Many other reports and four new Application Notes on diverse topics round off this issue. We hope you like it! Your Eppendorf BioNews Team All rights reserved, including graphics and images. Trademark information: p. 14. PS: Would you like to share your thoughts with us regarding BioNews? Do you have ideas or requests? If so, please send © Copyright Eppendorf AG, July 2019. us an e-mail to [email protected] Carbon neutrally printed in Germany. CONTENTS 3 7 8 9 IN THE SPOTLIGHT New pipetting system: 384. Ready. Set. Pipette! 4 – 5 STRAIGHT FROM THE LAB NGS sample preparation: 5 points why automation is worth it 10 – 11 Digitize your −80 °C treasures! 12 Small accessories – big impact 13 INNOVATION Creativity and the love for even the smallest of technical details 6 Eppendorf Conical Tubes 25 mL 8 CLOSE-UP Liquid addition to the bioreactor 13 NEWS / TIPS Ergonomics: always focusing on your needs 5 Perfect mixing can be that easy 7 Inside Cell Culture newsletter for professionals 7 Novelties in the 5.0 mL tube family 8 Expanded application range for large benchtop centrifuges 9 Eppendorf prize winners 2018/2019: Johannes Kohl & Georg Winter 14 SERVICE Trademark information 14 Prize competition: win a new pipetting system 15 (BN 51) JULY 2019 PAGE 1 RAFAL GRZESKOWIAK, DIANA HÜBLER Is That Really DNA in Your Tube? Comparative Analysis of UV-Absorbing Leachables in Micro-Test Tubes RAFAL GRZESKOWIAK AND DIANA HÜBLER, EPPENDORF AG, HAMBURG Is that really DNA in your tube? Comparative analysis of 1– 2 Abstract 40 °C, 24 h Bioactive contaminants leaching out of laboratory consum- ables (leachables) may significantly affect experiments and may pose a likely source of error in many assay systems. Non autoclaved 2.08 UV-absorbing leachables in micro test tubes Autoclaved Recent scientific evidence provides numerous examples of 2.0 biological assays, which have been shown to be affected by leachables, including routine applications such as spectro- photometric measurements of nucleic acids. This study 1.67 provides a comparative analysis of UV-absorbing leachables and 1.5 resulting false DNA readings 1.41 upon incubation of water sam- ULRIKE RASCHE ples in 1.5 mL micro-test tubes from several manufacturers. 1.07 0.98 0.97 A majority of tubes tested (see 1.0 0.95 0.91 Fig.