PreSens, Precision Sensing GmbH has been and still is the most advanced pioneer in implementing optical techniques for bio environment sensing of all key chemical elements – namely oxygen, CO₂ and pH. Its most successful range of optical oxygen sensing devices has won the attention of many and is now the honored leader of many copycats that jumped on the wagon.

While these products are still an important part of its over all business thanks to their superior quality, versatility and excellent affordability, PreSens has already sailed into new and most exciting analytical techniques, all based on its core technology which is optical fluorescence and subsequent sensing. Initially, two additional chemical species were added to the vast portfolio of measurement solution – i.e., dissolved carbon dioxide and pH.

 Adhesive spots for non invasive                Fixed needle for penetration                Miniature flow cell for closed loop

Sensing these chemical entities is now well established and almost all possible interfaces with the measured media are available, non invasive, needle based, implantable and immersion sensors are all available. To complete the line of needed techniques for the bio environment science PreSens has delivered superb tools such as Dish Readers for up to 24 wells for oxygen, CO₂ and pH.

                                     Dish reader for vials or wells                                             Multiple readers in parallel                      

Over the past few years PreSens has developed a ground breaking tool that combines the non invasive capability with two dimensional sensing capability. This tool named VisiSens has transformed the sensing of these species from a single point information into a two dimensional powerful mapping. It enables quantifying oxygen, CO₂ and pH visualizing their gradients and spatial distribution. This tool is essential for better understanding of biochemical processes in vivo and in vitro in both the space and time domains simultaneously.

        Mapping oxygen in soli without contact                                  Visualizing and monitoring leaf respiration

Mapping and quantifying oxygen distribution in pea seeds.
Depending on specific arrangement, a field of view of 40×32 mm and pixel resolution of 0.03 mm is available. With field of view of 12×10 mm the spatial resolution is 0.009 mm.

Recently, PreSens added another ground breaking tool in bio environment sensing, the SFR vario (Shaker Flask Reader) which is the only simultaneous device that will measure, Oxygen, pH, and biomass in a shaker flask inside an incubator remotely. To top this the supporting software will generate the OUR – Oxygen Uptake Rate information in real time so scientists can now complete several experiments within one set-up, saving huge amount of time, labor and money.

The sophisticated software allows several additional calculations of parameters such as cell dry weight, cell concentration once basic correlations are established in a relatively simple procedure. This tool can monitor up to 4 flasks simultaneously, and deliver all that data by a wireless Bluetooth to a nearby PC.

Real time monitoring oxygen, pH, biomass in SFR Vario

This data can be then plotted along with data about glucose and lactose as they are added and consumed. Thus, with practically one set-up it is possible to investigate the response of a population of bacteria, e.g., E. Coli to changes in the type of nutrition as well as other factors. If we also follow Biomass at the same time we will get a plot as shown below.

We can observe the response to switching from glucose to lactose in the small square.
Real time set-up of 4 SFR Vario flasks in an incubator monitored simultaneously and displayed on a PC screen.