This thesis presents the development of nucleic acid detection tests using magnetic nanoparticles, micro-magnets, and localized fluorescent detection, in collaboration with the start-up MagIA diagnostics. MagIA diagnostics focuses on rapid and portable immunological tests for point-of-care screening. Their technology combines micro-magnets, magnetic nanoparticles, and localized fluorescent detection without a washing step. MagIA diagnostics tests utilize magnetic nanoparticles conjugated with specific antibodies or antigens to detect target molecules. A first laboratory device has been developed, and a second device, suitable for point-of-care screening for HIV, HCV, and HBV, is in the final stages of development. The aim of the thesis is to use MagIA diagnostics technologies to conduct point-of-care molecular biology tests by purifying nucleic acids, amplifying a target sequence, and detecting the amplified DNA. A method using magneto-phoresis has been developed to purify DNA within a cartridge. The isolated nucleic acids are then amplified by PCR or LAMP and detected using magnetic nanoparticles functionalized with streptavidin. The results demonstrate high sensitivity and specificity of the developed detection system.