At this point, it becomes clear that in order to develop an efficient MOF-based SERS detection platform, the structure of both the plasmonic metallic part and MOFs must be mutually tailored. For example, mere design of the MOF constituent for fast diffusion of the analyte through its microporosity is not sufficient if the plasmonic characteristics of caped metallic nanostructure are detuned and tight confinement of electromagnetic field does not occur. This important interplay was nicely demonstrated in the work of He et al. Here, the authors synthesized single-core Au@MOF-5 NPs by the one-pot approach: all reactants were mixed together (Au NPs precursors, PVP for their later capping and stabilization, and Zn(NO3)2 and terephthalic acid, the MOF precursors). Given the time differences in the nucleation and growth processes, Au NPs were first grown withing this mixture, and then they were modified by PVP, which stabilizes them. Later, MOF-5 nucleation started from the surface of the Au NPs, developing well dispersed single-coreshell Au NP, as seen in Figure . By controlling the synthetic conditions, Au cores with diameters of 54±7, 38±7, and 30±7 nm were obtained, and the MOF shell thickness varied for each case: 3.2±0.5, 25±4, 69±12 nm respectively. These core-shell structures were then employed for the detection of CO2, capable of diffusing across the MOF microporous structure. As shown in Figure -ii, NPs with 54±7 nm Au cores and 3.2±0.5 nm thick MOF-5 shells were the only ones that presented activity towards the detection of CO2 despite the fact that all of the composites were crystalline and porous. This result makes clear the need for optimizing the complete structure of the MOF-SERS substrate. It is not only the contribution of the MOF-5 shell that has an impact on the performance, but also the size of the plasmonic NPs needs to be adjusted respectively.