Research

When culturing any bacteria or cells, it is important to monitor the growth. The density of a culture determines, for example, its state and production yields. The current standard for measuring the growth of cultures is to measure the optical density (OD), in which the intensity of the light transmitted through the sample is compared to the intensity of the incident light. These measurements are often only taken at large time intervals and manually. They do not provide any information about the actual concentration of bacteria or cells. In this project, we will develop an automated system that provides users with the concentration of bacteria or cells during cultivation. The key enabling technology is high-throughput 3D microscopy, supported by precise automated dilution, integrated with the Hololoid holographic imaging and analytics platform.

In this project we want to couple the powerful methods of holographic microscopy for water analysis with state of the art IoT and AI methods. We will build and deploy several holographic microscopes to collect and characterize water samples locally at a few strategically chosen locations in the network. These holographic microscopes take samples fully autonomously and image each and every light scattering object in the sample volume. This is done by shining coherent light through the sample where some of the light is scattered by microscopic objects dispersed in the water. This scattered light interferes with the unscattered fraction of the illuminating light on the detector array of the microscope. By numerical back propagation we can locate each and every object in the sample volume that scatteres enough light to be distinguished. By repeating the procedure we can track the objects’ motion. In practice this method allows to characterize what is in the water in terms of plastic objects, plant fragments, sediments, small animals, algae and bacteria. In this project we want to correlate the wealth of information about dispersed objects in water with time series of currently available quality parameters. We will analyse the supply network and current sample collection sites to strategically place our holographic microscopes in the water supply network objective to make the early detection of environmental issues possible. 

The basis for our technology is the so-called inline holography microscopy. We shine coherent light through a transparent volume with microscopic objects like bacteria, spores, algae, microplastics, etc. in it. These objects scatter a small amount of this light. The scattered light interferes with the illumination beam, creating interference patterns that are recorded by a camera. The breakthrough technology to be further developed in this project uses recorded in-line holograms to calculate the full light field in the entire sample volume by backpropagation or numerical refocusing. This offers several advantages: 1. the ability to numerically refocus after image acquisition greatly simplifies data acquisition. 2. cells and environmental particles can be observed in their natural 3D environment. 3. it is possible to observe many more objects simultaneously than is possible with conventional microscopy, and it is possible to record a continuous flow of an analyzed fluid. Based on the data collected with this technology, Holloid aims to develop algorithms that will allow researchers and environmental analysts to simultaneously detect and quantify bacteria and microparticles using a microscope/sensor suitable for environmental monitoring, including groundwater. This will provide a new means for those responsible for water quality in the environment and, ultimately, in drinking water to gain insights with significant implications for the health of our ecosystems and people. Ultimately, the results of this project can form the basis for numerous other applications in environmental monitoring and beyond.