# Lab-on-Chip Culturing System for Fungi--Towards Nanosatellite Missions
## 1 Introduction  
Contemporary techniques of microfluidics find applications in most of the scientific branches, especially in the field of life sciences, where reliable, fast and automated analysis is indispensable [1, 2, 3]. Rapid development of laboratory-on-chip devices and accompanying new methodologies ensure new insights into biomedical solutions by providing substantial improvements over often complex and labour-intensive protocols [4, 5, 6]. High throughput screening, manipulation and analysis based on single cell techniques; perspective for very specific LOC designs with simultaneous ease of integration and relatively low costs bring new advances for diagnostics and biomedical engineering [7, 8, 9, 10, 11]. However, there are still a few domains in which the potential of LOCs has not been fully recognised, and one of these branches may be considered to be mycology. In principle, mycology is the biological discipline that covers the study of fungi. This is a kingdom of a vast group of organisms (both macroscopic and microscopic) of great significance, especially in the context of the so-called tree of life [12, 13]. Investigation of fungi encompasses not only their taxonomy, genetic and biochemical properties, but also multiple beneficial and harmful effects that have a notable impact on our daily lives [14, 15, 16]. Fungi can be considered to be fairly dangerous, e.g., some species are pathogenic towards plants or cause human and animal diseases. On that basis, special control andin-depth investigation of both uniform colonies and the mutual relationships with other environmental organisms is significant and necessary. Microscopic fungi also find application in diagnostics and plant health evaluation--i.e., in crops, plants, and rare and precious species--in identification of new fungi species and their genetic mutations, track changes in environmental and impact fungi for other organisms and our daily lives [17]. As was mentioned previously in this paper, the application of miniaturised microfluidic tools for myology is currently quite limited, but gradually growing in popularity. The first report on the usage of a lab-on-chip for myology, to the best of the authors' knowledge, was published in 2010 by [PERSON] et al. [18]. The paper mentions biological responses of two diverse filamentous fungi confined in miniaturised PDMS mazel-like structures, pointing to specific, previously unknown directional growth of these species. Further works within this scope appeared in 2016, in which the paper released by [PERSON] et al. was especially interesting [19]. Herein, the idea of, so-called, soil-on-a-chip was presented, showing the significance of the development of microfluidic platforms for the study of environmental creatures. The article put forward the interactions of soil-dwelling organisms (e.g., nematodes, bacteria, plants, etc.) with special attention paid to fungi as excellent bioindicators of any physical/chemical changes in the local habitats [20; 21; 22]. Similar issues were raised by the same scientific group recently in [23] and [24], where [PERSON] et al. present positive results of the application of PDMS lab-on-chip for stationary co-culture of selected filamentous fungi and bacteria. There are also other papers that discuss the demand for microfluidics in myology, but not in the context of environmental studies, but rather as advanced techniques for identification of pathogenic fungi in food or blood samples [25; 26; 27], utilising modern real-time PCR methods [28] or inertial focussing chip-based platforms [27]. Although some examples of fungi investigation utilising lab-on-chip solutions can be found in the literature, there is still a lack of fully featured, portable and miniaturised instruments that would ensure long-term cultivation of these interesting species that also have the capacity to automatically change the culturing conditions, for instance nourishment flow and temperature, and to constantly monitor the colony.