Here, we describe a preassembled plasmonic resonance nanocluster. One embodiment is used for microbe detection and typing. The metallic nanoparticle acceptors with microbe surface antigen epitope, and quantum dot (QD) donors with Fab antibody, are assembled into an immuno-mediated 3D-oriented complex with enhanced energy transfer and fluorescence quenching. The coherent plasmonic resonance between the metal and QD nanoparticles is exploited to achieve improved donor-acceptor resonance within the nanocluster, which in the presence of microbial particles is disassembled in a highly specific manner. The nanocluster provides high detection specificity and sensitivity of the microbes, with a sensitivity limit down to 1-100 particles per microliter and to attomolar levels of a surface antigen epitope. A few specific examples of the plasmonic resonance nanocluster used in microbe detection are disclosed along with ways in which the complex can be easily modified for additional microbes.
 The United States Government has rights in this invention pursuant to DOE Contract No. DE-AC02-05CH11231 between the U.S. Department of Energy and the University of California, as operator of Lawrence Berkeley National Laboratory.