Thanks to the development of theoretical foundations and technical methods in manufacturing Light Emitting Diodes (LED), many innovative design ideas and applications have been developed and recorded in many fields. Previously, blue light (400-470 nm) has successfully shown the ability to inactivate many strains of harmful bacteria. In this context, we fabricated a 405 nm LED panel with the full width at half maximum (FWHM) of ~10 nm to illuminate common harmful bacteria strains, including Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). A LED panel consists of 6 LEDs with nanowire structure arranged in a uniform hexagon. The LED panel is composed of functional components for easy replacement and improvement which provides to the safety and convenience of use. We checked the photoelectric parameters to prove the ability of the LED panel to work continuously in high power mode with a proper temperature for practical use. We observe that the panel under specific experimental conditions shows the bacterial inactivation rates of up to 90% for S. aureus at 10-6 CFU/ml. According to the design calculations and practical measurements related to the LED system, a series of reliable parameters has been collected, showing the suitability to become a device used in bacterial inactivation experiments.