Sample labeling and storage management in research

Manual labeling of samples is still a fairly common practice in research laboratories. Along with the rather complex and individualized sample management, this can make tracking and retrieving samples much more difficult. A research team from the Technical University of Munich is now using a mobile app for sample labeling and logistics in cancer research.

This text was first published in the print an online edition of March 2021 and translated to English; original article ( German), link for PDF download (German)


Stefanie Bärthel; PhD student in the “Translational Tumor Research” group of Prof. Saur; TranslaTUM Munich Central Institute for Translational Cancer Research at the Technical University of Munich | Dr. Claudio Rolli; Founder and CEO FLUICS GmbH, Munich

Professor Dr. Dieter Saur and his team decipher the mechanisms of tumor development at the molecular level. His research is part of the German Consortium for Translational Cancer Research (DKTK) and is funded by the German Center for Cancer Research (DKFZ). The laboratories are located in the partner office in Munich (TranslaTUM).

In their research experiments tissue samples from biopsies or animal models, which are difficult and labour intensive to obtain, are analyzed for their molecular composition. Before samples are ready for experimentation, they must first be tested for suitability using a series of standardized tests (for example, by sequencing and protein analysis). During this time, the samples are temporarily stored in freezers at -20 °C for several days or weeks.

Once the samples have passed this suitability test, they are carefully prepared: tissue samples are cut into thin slices, stained with fluorescent marker molecules, and finally examined under a microscope in order to decipher the mechanisms by which tumors develop.

These tissue samples are very valuable and are therefore stored for possible further investigation and future research projects. For long-term storage small plastic tubes filled with samples are transferred to special freezers at -80 °C or immersed in tanks filled with liquid nitrogen (-196 °C). Only if stored under such extremely cold conditions, one can be sure that the biological structure and composition of the samples will not deteriorate and will be available for research even after many years.

Nitrogen tanks for long-term preservation of biological samples.

Complex sample management requirements

Professor Saur’s 36-member working group analyzes up to several hundred samples weekly. Until recently, all plastic tissue sample tubes were manually labeled with a marker and recorded in various Excel lists so that they could be unambiguously assigned to experiments and retrieved later. For larger studies, a label printer was used that could print many labels very quickly. However, since the printer was not connected to a database, individual sample information had to be manually entered into many Excel spreadsheets – not only a very tedious work but also highly prone to errors.

In the past, this has repeatedly led to the loss of samples or the inability to find them again. Either the handwriting was no longer readable, or labels that were not intended for use in liquid nitrogen peeled off and floated in the nitrogen tank, or the Excel spreadsheets were not checked regularly to make sure they were up-to-date, or the manually entered text contained typos.

Mislabeled samples and poorly maintained inventory tables can have serious research implications. Not only does it take a lot of time to find samples. In the worst case, valuable samples are lost in the depths of freezers, nitrogen tanks and other storage facilities, and experiments cannot be replicated. Another aspect that is becoming more and more important nowadays is the high costs and high energy consumption associated with operating ultracold freezers at -80°C and cooling with liquid nitrogen. In order to store biological samples in a cost effective way and with a minimal impact on the environment, it is important to make the most of the available storage space and avoid opening the freezer with no obvious necessity.

Ultra-low temperature freezers for long-term storage of biological samples at –80 °C.

Hand-labeled samples – still commonly found in research

The fact that samples are manually labeled in the laboratory, as in the working group of Professor Saur, is not an isolated case. It is in the nature of research that the processes (experimental procedures) in the laboratory change frequently and cannot be planned in the distant future. Automatic labeling and sample handling with so-called LIMS (Laboratory Information Management Systems) have been on the market for several decades and can be found in all analytical or diagnostic laboratories.

However, LIMS systems have failed to prevail in day-to-day research: high acquisition and operating costs, as well as time-consuming user training in well-defined organizational structures, cannot pay off over a period of years if experimental procedures are constantly changing. In addition, since samples are pipetted and processed manually in the laboratory, human-friendly labeling is essential. Therefore, sample containers with printed barcodes and without individually adaptable text are not practical. This is why quick access to the pen and “tried and tested Excel spreadsheets” still exist in most research labs.

Cryoboxes with barcodes in a  -80 °C ultra-low temperature freezer.

Sample labeling and tracking checklist

The basic requirements for inventory management in research laboratories are quite complex and can be divided into labels and databases.


  • Resistant to extreme temperatures from -196 °C in liquid nitrogen to + 100 °C in a water bath.
  • Protection against wiping from solvents such as ethanol and isopropanol for sterilization.
  • Readable text for quick sample assignment in manual workflows (pipetting).
  • Scannable code for digital and error-free sample management.

Database / Logistics

  • High flexibility to quickly adapt to frequent changes in experimental procedures.
  • Unified access for all employees to one database.
  • Unique sample IDs that can be scanned to manage sample information (storage location, content, etc.) in an error-free way.
  • Fast and intuitive installation and management that users do not perceive as an additional workload.

Sample management with mobile app

The young startup “FLUICS CONNECT”, founded by researchers at the Technical University of Munich, has developed a new holistic solution for labeling and sample handling that is specifically tailored to the requirements of research laboratories. The mobile app turns any smartphone into a scanner, provides mobile access to a shared database and quickly prints labels with QR codes and readable text.

When Professor Saur first heard of this solution, he became enthusiastic about it on the spot. After a brief consultation with his team, Professor Saur received immediate approval from his staff to implement the Fluics Connect inventory solution. During the two-week long initial test phase, graduate student Stefanie Bärthel started using a new smartphone that had been purchased for the lab to label her samples with new labels.

After that, her colleagues also integrated the application into their daily workflows in a couple of days. Today in the working group, samples are hardly marked by hand. In addition, a large number of stored samples were gradually re-labeled with the new QR-coded labels.

With the first 10,000 samples having beeng labeled with the new QR-codes by the group within one year, Professor Saur comes up with a positive result: “Until recently, I was disappointed with how complex and unreliable our samples were managed. It happened again and again that we looked for a sample from an old experiment to test it in a new experiment, but in the end we could not find the sample, although we tried to establish different rules and label printers. This is no longer happening with our new labels. By using barcodes and the mobile app, we can also quickly and reliably update information about storage location and other sample-related parameters. This would not have been possible with our old Excel spreadsheets.”


Sample management in research laboratories is very complex, different from lab to lab and must be very flexible to adapt to the researcher’s needs. Today, hand-labeled samples and Excel spreadsheets as inventory databases are still the status quo in 90% of research labs. The Munich research lab’s experience proves that mobile apps that can turn any smartphone or tablet into a barcode scanner and label printing solution can be an effective alternative to pens and Excel spreadsheets.

Cryobox with frozen tumor samples. Samples are labeled with barcodes and text so that they can be found and clearly assigned, even over time.

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