By roughly mimicking the surface architectural design of dragonfly wings, novel bi-phasic 3D nano-flowers of MgO/Mg(OH)2 were successfully synthesized via electrospinning technique. The 3D nano flowers were coated over commercial melamine sponge and extensively characterized by SEM, XRD, FTIR and EDS. The formation of distinct dense 3D nano petals was revealed by SEM images whereby the mean petal thickness and mean distance between the adjacent petals were found to be 36 nm and 121 nm, respectively. The bactericidal activities of synthesized 3D nano-flowers coated melamine sponges were assessed against five different bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa). This study demonstrated significant bactericidal activity of MgO/Mg(OH)2 3D nano flowers coated MS against both Gram-positive and Gram-negative bacteria. Plausible bactericidal mechanisms include physical stretching, puncture and shearing of bacteria cell walls. This study serves to introduce novel bioinspired biomaterial with capacity to reduce risk associated with pathogenic bacterial infections especially in medical devices.