The rapid, highly sensitive, and accurate detection of bacteria is the focus of various fields, especially food safety and public health. Surface‐enhanced Raman spectroscopy (SERS), with the advantages of being fast, sensitive, and nondestructive, can be used to directly obtain molecular fingerprint information, as well as for the on‐line qualitative analysis of multicomponent samples. It has therefore become an effective technique for bacterial detection. Within this progress report, advances in the detection of bacteria using SERS and other compatible techniques are discussed in order to summarize its development in recent years. First, the enhancement principle and mechanism of SERS technology are briefly overviewed. The second part is devoted to a label‐free strategy for the detection of bacterial cells and bacterial metabolites. In this section, important considerations that must be made to improve bacterial SERS signals are discussed. Then, the label‐based SERS strategy involves the design strategy of SERS tags, the immunomagnetic separation of SERS tags, and the capture of bacteria from solution and dye‐labeled SERS primers. In the third part, several novel SERS compatible technologies and applications in clinical and food safety are introduced. In the final part, the results achieved are summarized and future perspectives are proposed.
From a geometrical perspective, a chiral object does not have mirror planes or inversion symmetry. It exhibits the same physical properties as its mirror image (enantiomer), except for the chiroptical activity, which is often the opposite. Recent advancements have identified particularly interesting implications of chirality on the optical properties of metal nanoparticles, which are intimately related to localized surface plasmon resonance phenomena. Although such resonances are usually independent of the circular polarization of light, specific strategies have been applied to induce chirality, both in assemblies and at the single-particle level. In this tutorial review, we discuss the origin of plasmonic chirality, as well as theoretical models that have been proposed to explain it. We then summarise recent developments in the synthesis of discrete nanoparticles with plasmonic chirality by means of wet-chemistry methods. We conclude with a discussion of promising applications for discrete chiral nanoparticles. We expect this tutorial review to be of interest to researchers from a wide variety of disciplines where chiral plasmonics can be exploited at the nanoparticle level, such as chemical sensing, photocatalysis, photodynamic or photothermal therapies, etc.