Projects

The COVID-19 pandemic has kept the world in suspense since the beginnings of 2020. Thorough serosurveillance of reconvalescent patients and vaccinated individuals might be key in the way back to normality. Therefore, we work on the development of immunoassays for the rapid automated detection of antibodies to SARS-CoV-2.

The world is still threatened by the COVID-19 pandemic, but high hopes are placed in the vaccination, promising immunity and a return to normality. Hence, the monitoring of immunity by antibody tests is highly relevant but commercial tests like ELISAs are often time-consuming, laborious and sometimes exhibit insufficient sensitivity as only one antigen can be considered. We make use of the long-established microarray chips for the automated analysis platform MCR 3 and the more recently developed MCR-R and are developing an indirect, non-competitive microarray immunoassay that allows for the simultaneous detection of IgG and IgM antibodies to SARS-CoV-2 receptor binding domain, spike (S1) and nucleocapsid protein within eight minutes. Future activities in the project will also focus on the quantitative evaluation of test results, the establishment of neutralization assays in microarray format and the rapid adaptation to different antigens, e.g. in case of mutations of SARS-CoV-2.

Funding: BFS (AZ 1438-20C)

Infections in human body fluids are quite severe, with increasing mortality until treatment. Therefore, a rapid and precise treatment – and consequently, a rapid and precise detection – is essential. By enrichment with monolithic affinity filtration and detection with DNA-based methods, we aim to improve the whole detection process of pathogens causing infection.

In case of an infection in human body fluids, not only fast treatment decides over life and death, but also precise medication is absolutely crucial in respect to antibiotic resistances. In order to achieve this, the causing pathogens – bacteria and fungi – and their potential resistances need to be identified as quickly as possible. The gold standard used are culture-based methods, which need a long time, due to the low concentration of pathogens inside the body fluids. By enrichment of the pathogens using specific affinity linkers on monolithic filters, it is possible to provide a faster analysis. By additional application of a DNA-based method, the heterogeneous asymmetric recombinase polymerase amplification (haRPA) on the MCR 3, enrichment and detection could be performed within one day.

Funding: Deutsche Forschungsgemeinschaft (DFG) through TUM International Graduate School of Science and Engineering (IGSSE)

AuNPs have drawn big attention in the CL system for biosensing application. The relationship between catalytic activity and synthesis parameter of AuNPs is uncertain. Therefore, we integrate 3D microreactor with chemiluminescence system for online synthesis of AuNPs and catalyst characterization.

AuNPs have drawn big attention in the CL system with excellent properties, and the catalytic activity of AuNPs depends on size, shape and surface charge property. It is difficult to confirm the optimal condition of AuNPs for a certain CL system. A 3D hydrodynamic focused microreactor was used to synthesize AuNPs through a single-phase reaction at room temperature. The synthesis was coupled directly with a CCD camera with luminol-NaOCl reaction for catalyst characterization. All operations were performed in an automatic way. The property of AuNPs was easily controlled by tuning concentration of reagents in a 3D microreactor during synthesis. Effect of aggregation and surface property of AuNPs on catalytic activity can also be monitored. For further application, synthesized AuNPs can be bound with antibody or aptamer for specific detection of analytes.

Funding: China Scholarship Council

The increased growth of cyanobacteria is favored by climate change as well as the eutrophication of water bodies and have been observed more frequently in recent years. Often, potential dangers from algal blooms are not discovered until accidents have occurred. To prevent this, it is essential to develop an early warning system for increased algal growth and the release of algal toxins.

Mass propagation of cyanobacteria poses a threat to the environment and human health all over the world by producing a variety of toxic substances that can cause poisoning, allergic reactions and skin irritation. In order to prevent accidents and hazards from cyanotoxins, the European Bathing Water Directive § 8 requires that appropriate monitoring should be carried out for bathing waters whose profile indicates a possible mass propagation of cyanobacteria. It further requires that appropriate managerial action shall be taken as soon as a mass propagation or potential health hazard is detected. Despite these precautions, accidents due to cyanotoxins continue to occur, as experienced in the summer of 2019 at Lake Mandicho. After the death of several dogs, a restriction on the use of the lake was imposed for more than one month. The cause of death of the dogs was clarified weeks later, with the cyanotoxin anatoxin a, identified as the cause. In the case of suspected algal blooms, it is important to quickly gain clarity about the current situation in order to be able to act appropriately. Therefore, a comprehensive and continuous monitoring of the waters is necessary, as well as a fast and reliable method for the identification and quantification of cyanotoxins. To ensure this, in this project a multiplex algal toxin immunoassay will be developed on the platform of the MCR-R, which will be able to quantify different algal toxins simultaneously and within minutes, and therefore guarantee the safety of bathing waters.

Funding: AIF-ZIM (ZF4810901LL9)

In Germany, over 1.200 agricultural exhaust air purification systems are used in pig or poultry farms. While some exhaust air scrubbers work with chemicals or low pH to prevent microbial growth, biofilters are using an active microbiome for the purification of the barn air. This leads to an ideal growth condition of various bacteria, including airborne human pathogens like Legionella. To understand the potential health risks of Legionella in biofilters, a robust and reliable detection method needs to be developed.

Legionella spp., a group of 2-20 µm large, gram-negative bacteria are found in all kind of freshwater systems. In the last years, increasing number of legionellosis outbreaks, a severe lung disease is a growing challenge for public health. Infection with Legionella spp. usually takes place via aerosols. Therefore, in addition to the shower, cooling towers, evaporative cooling systems where the prevalence of Legionella is already intensively investigated, agricultural exhaust air purification systems can be a potential risk. Biotrickling filters, used in pig farms to remove e.g. odor, dust and nitrogen are working with an active microbiome which results in no possible treatment with biocides. This leads to ideal growth condition of various bacteria, including Legionella. According to the EN ISO 11731:2017 the gold standard for the detection of Legionella is a culturing method. For that, after a long incubation time of 7 – 10 days on selective agar the colony forming units (CFU) can be determined. Research has shown that this approach has a high risk for underestimating the number of infectious bacteria. The reason for that are viable but not culturable Legionella. That´s why upcoming alternative detection methods like molecular biological approaches are becoming increasingly popular. But these methods are often highly influenced by complex matrices or need a laborious experimental setup. For this reason, a fast, reliable and robust assay has to be developed and used for monitoring and quantification of Legionella in biofilters. 

Funding: Dieses Projekt wurde aus Mitteln des Bundesministeriums für Ernährung und Landwirtschaft (BMEL) gefördert. FKZ 28N-2-002-02. Laufzeit: 1.8.2020 - 31.7.2023.

Cooling towers, evaporation coolers  and wet separators can be responsible for Legionellosis outbreaks by releasing contaminated bioaerosols over several kilometers. The detection standard is the culture method with several disadvantages like slight growth time, wherefore it does not describe the current statues of such artificial water systems. Because of this, the validation and characterization of culture-independent methods is necessary to improve the screening and detection capability.

Legionella appear normally in our environment, but under certain circumstances they can also contaminate artificial water systems like cooling towers, evaporation coolers and wet separators. The species Legionella pneumophila and especially its serogroup (Sg) 1 is the most pathogenic and common danger for humans. Inhalation of Legionella contaminated bio aerosols can cause bronchial pneumonia called legionnaires’ disease with a mortality rate up to 10%. Rarely, Legionella can also cause outbreaks. For this unfortunate case artificial water systems can be responsible, because of releasing Legionella contaminated aerosols over several kilometers, which can be inhaled by a variety of people. Since 2017 the 42. BImSchV law is in force in Germany, which regulates the water quality of cooling towers, evaporation coolers and wet separators. These systems get screened in regular periods to determine the microbiological exposure with reference to the and intervention values. According to the EN ISO 11731:2017, the most used method to analyse these water samples is the culture method with several disadvantages. Legionella colonies can be counted after 7 - 10 days growing time and this slight growth time rate supports overgrowth with accompanying flora. In addition, Legionella can skip to a so-called viable but non-culturable (VBNC) state, while they are still pathogenic, but can’t be detected via the culture method anymore. The industry is therefore looking for faster and culture-independent screening methods that can describe the current status of artificial water systems, which are not standardized in Germany, yet. For this, our institute developed the chemiluminescence sandwich microarray immunoassay (CL-SMIA) which is a culture-independent screening method for detection and serotyping of Legionella pneumophila so-called LegioTyper. In the project, cultivation-independent methods (molecular biological methods like qPCR and antibody-based methods (flow cytometry and CL-SMIA) are standardized for a better hazard analysis in evaporation coolers and cooling towers. 

Funding: BMWE WIPANO-LegioRapid (FKZ 03TN0002A)
www.legiorapid.de