As summarized in Figure , casted-particles substrates represent more than 50% of the reported experiments for MOF-based SERS substrates, probably due to the versatility and relatively straightforward synthesis without the need of complex infrastructure. Solid substrates prepared by lithographical means account for 30% of the cases. As shown in Figure , solid substrates allow for a more precise control over the EF obtained compared to casted SERS substrates. If the average of the reported values is compared, EF achievable by solid substrates (1.74 •10 6 ) are 4 times higher than the ones obtained from casted particles (4.38 ) and present a narrower distribution, probably due to the fine-tuning of the morphology of the surface by nanolithografic approaches.