A novel sensitive pathogen detection system based on Microbead Quantum Dot System

A fast and accurate detection system for pathogens can provide immediate measurements for the identification of infectious agents. Therefore, the Microbead Quantum-dots Detection System (MQDS) was developed to identify and measure target DNAs of pathogenic microorganisms and eliminated the need of PCR amplifications. This nanomaterial-based technique can detect different microorganisms by flow cytometry measurements. In MQDS, pathogen specific DNA probes were designed to form a hairpin structure and conjugated on microbeads. In the presence of the complementary target DNA sequence, the probes will compete for binding with the reporter probes but will not interfere with the binding between the probe and internal control DNA. To monitor the binding process by flow cytometry, both the reporter probes and internal control probes were conjugated with Quantum dots that fluoresce at different emission wavelengths using the click reaction. When MQDS was used to detect the pathogens in environmental samples, a high correlation coefficient (R=0.994) for Legionella spp., with a detection limit of 0.1ng of the extracted DNAs and 10CFU/test, can be achieved. Thus, this newly developed technique can also be applied to detect other pathogens, particularly viruses and other genetic diseases. •We develop a new system to qualitative and quantitative determination for pathogens.•We labeled quantum dots into oligonucleotide probes by Click reaction.•The advantages of this system are longer storage, qualitative detection and PCR -free.•This system shows high specificity and sensitivity with the detection limit as 10CFU/test.•The combination of different QDs, the various targets were able to be distinguished.•.