## 1 Introduction  
Chirality plays a major role in nature. It is almost ubiquitous because of the presence chiral building blocks, such as carbohydrates and amino acids, used for the creation of advanced covalent and supramolecular structures, i.e., proteins, enzymes, and glycoconjugates (such as glycoproteins and glycolipids) [1]. As such, most bioactive species exhibit chiral features and many key biological mechanisms possess specific interactions with chiral molecules [2; 3; 4]. Up until now, the source of homochirality in the monomeric units of biopolymers in nature is one of the main scientific queries that still remains unexplained. The motive as to why only L-amino acids and D-monosaccharides are present in alive organisms is still unknown. The choice of a single enantiomer in biomolecules, e.g., by impulsive self-assembling into planned shapes, is a procedure that is not yet clear [5].  
Chiral recognition also plays a key part in the field of chemical, biological, and pharmaceutical sciences because of the precise orientation of functional groups in chiral molecules [6; 7; 8; 9]. Many active pharmaceutical ingredients (APIs) are chiral and the two enantiomers often present different pharmacokinetic, therapeutic, and toxicological profiles. Since the application of 1990s guidelines about stereochemistry in drug discovery and development, most drug companies and research institutes have focused their attention on single enantiomers. Furthermore, many active enantiomers of drugsthat are already commercialized in racemic mixture have been patented as single APIs as soon as the old patent expired, a phenomenon known as chiral switching [10].  
Advances in nanotechnology have led to an ever-increasing fabrication and consumption of engineered nanoparticles (NPs) and the enormous steps made forward in material science and medical applications have been extensively acknowledged [11; 12; 13; 14]. Chiral molecules adsorbed on an appropriate surface show a significant role in stereoselective heterogeneous catalysis [15] and material science [16].  
Chiral NPs have been known since 2007, when [PERSON] et al. determined the structure of a 102-atom gold nanoparticle (Au NP) covered with 44 \(p\)-mercaptoethanol acid molecules and noted a symmetric _fcc_ core surrounded by an asymmetric shell of Au atoms bound to the thiol of the ligands, thus yielding inherently chiral NPs with the two enantiomers alternating in the crystal lattice [17]. More recent studies have evidenced that achiral metallic nanoparticles show chiral properties that are determined by amino acids and peptides bound to their surface. As a consequence, such NPs can produce strong chiral optical signals even at visible wavelengths and they could be exploited for a variety of applications, from enantioselective recognition to asymmetric catalysis and sensing, as well as biomedicine.  
In this article, we review the recent applications of chiral NPs. We concentrated our attention on the molecules employed for functionalizing the surface of the NPs and the way in which they allow for the obtaining of specific interactions with the host in solution. In general, metallic NPs have been used, such as gold and silver NPs, or magnetic NPs, for exploiting their ability to be attracted by an external magnetic field and separate enantiomeric species, or quantum dots (i.e., CdSe/CdS core-shell NPs) for taking advantage of their photoluminescent capacity. On the other hand, carbohydrates and amino acids are the main, but not the only, ligands used for obtaining the enantioselective interaction.