Application of nanoparticles in chiral analysis and chiral separation

Chirality in Insecticide Design and Efficacy

Chirality plays a crucial role in the design and efficacy of insecticides, significantly influencing their biological activity, selectivity, and environmental impact. Recent advancements in chiral insecticides have focused on enhancing their effectiveness, reducing toxicity to nontarget organisms, and improving environmental sustainability. This review provides a comprehensive overview of the current state of knowledge on chiral insecticides, including neonicotinoids, isoxazolines, and sulfiliminyls. We discuss the stereochemistry, synthetic development, mode of action, and environmental fate of these compounds. The review highlights the importance of chirality in optimizing insecticidal properties and underscores the need for continued research into novel chiral compounds and advanced synthesis technologies. By understanding the role of chirality, we can develop more effective and environmentally friendly insecticides for sustainable pest management.

Stereoselective transport of 2-aryl propionic acid enantiomers in porous media subjected to chiral organic acids

The study examined the transport behavior of the 2-aryl propionic acid (2-APA) chiral pharmaceutical enantiomers by means of a laboratory-scale saturated quartz sand column experiment. Four typical of 2-APA and their enantiomers were selected for the study under different types of chiral organic acids (COAs)-mediated effects. Differences in the transport of the 2-APA enantiomeric pairs have been identified in response to various pH, types of COAs, and enantiomeric structures of COAs. Redundancy analysis identified the factors responsible for the largest differences in transport of 2-APA enantiomeric pairs, while spectroscopic characterization and density function theory (DFT) studies elucidated the underlying mechanisms contributing to the differences in transport of enantiomeric pairs. Obvious correlations among homochirality or heterochirality between COAs and 2-APA enantiomeric pairs were observed for changes in the mobility of 2-APA. The results indicate widespread COAs significantly affect the transport behavior of chiral man-made chemicals, suggesting more attention is needed to fill the gap in the perception of the transport behavior of chiral compounds.

Green and Red Emissive N,O-Doped Chiral Carbon Dots Functionalized with l-Cysteine

Although chirality plays an important role in the natural world, it has also attracted much scientific attention in nanotechnology, in particular, spintronics and bioapplications. Chiral carbon dots (CDs) are promising nanoparticles for sensing and bioimaging since they are biocompatible, ecofriendly, and free from toxic elements. Herein, green and red emissive chiral CDs are fabricated via surface modification treatment of achiral CDs at room temperature. After modification with l-cysteine molecules, the treated CDs demonstrate an intense chiral signal in the region of 200-300 nm with a dissymmetry factor up to 2.3 × 10-4 and high photoluminescence quantum yields of 19% and 15% for green and red emission bands, respectively. These CDs preserve their chiral signal in different ion systems, such as those with pH changes or in the presence of metal ions, along with remarkably low cytotoxicity, making them potential candidates for use as photoluminescent labels for biological objects.

Polymeric Carbon Nitride with Chirality Inherited from Supramolecular Assemblies

The facile synthesis of chiral materials is of paramount importance for various applications. Supramolecular preorganization of monomers for thermal polymerization has been proven as an effective tool to synthesize carbon and carbon nitride-based (CN) materials with ordered morphology and controlled properties. However, the transfer of an intrinsic chemical property, such as chirality from supramolecular assemblies to the final material after thermal condensation, was not shown. Here, we report the large-scale synthesis of chiral CN materials capable of enantioselective recognition. To achieve this, we designed supramolecular assemblies with a chiral center that remains intact at elevated temperatures. The optimized chiral CN demonstrates an enantiomeric preference of ca. 14 %; CN electrodes were also prepared and show stereoselective interactions with enantiomeric probes in electrochemical measurements. By adding chirality to the properties transferrable from monomers to the final product of a thermal polymerization, this study confirms the potential of using supramolecular precursors to produce carbon and CN materials and electrodes with designed chemical properties.

Chiral Materials: Progress, Applications, and Prospects

Chirality is a universal phenomenon in molecular and biological systems, denoting an asymmetric configurational property where an object cannot be superimposed onto its mirror image by any kind of translation or rotation, which is ubiquitous on the scale from neutrinos to spiral galaxies. Chirality plays a very important role in the life system. Many biological molecules in the life body show chirality, such as the "codebook" of the earth's biological diversity-DNA, nucleic acid, etc. Intriguingly, living organisms hierarchically consist of homochiral building blocks, for example, l-amino acids and d-sugars with unknown reason. When molecules with chirality interact with these chiral factors, only one conformation favors the positive development of life, that is, the chiral host environment can only selectively interact with chiral molecules of one of the conformations. The differences in chiral interactions are often manifested by chiral recognition, mutual matching, and interactions with chiral molecules, which means that the stereoselectivity of chiral molecules can produce changes in pharmacodynamics and pathology. Here, the latest investigations are summarized including the construction and applications of chiral materials based on natural small molecules as chiral source, natural biomacromolecules as chiral sources, and the material synthesized by design as a chiral source.

Surface modified nanoparticles and their applications for enantioselective detection, analysis, and separation of various chiral compounds

The development of efficient enantioselective detection, analysis, and separation relies significantly on molecular interaction. In the scale of molecular interaction, nanomaterials have a significant influence on the performance of enantioselective recognitions. The use of nanomaterials for enantioselective recognition involved synthesizing new materials and immobilization techniques to produce various surface-modified nanoparticles that are either encapsulated or attached to surfaces, as well as layers and coatings. The combination of surface-modified nanomaterials and chiral selectors can improve enantioselective recognition. This review aims to offer engagement insights into the production and application of surface-modified nanomaterials to achieve sensitive and selective detection, better chiral analysis, and separation of numerous chiral compounds.

Chiral Optical Properties of Möbius Graphene Nanostrips

The advancement of optical technology demands the development of chiral nanostructures with a strong dissymmetry of optical response. Here, we comprehensively analyze the chiral optical properties of circular twisted graphene nanostrips, with a particular emphasis on the case of a Möbius graphene nanostrip. We use the method of coordinate transformation to analytically model the electronic structure and optical spectra of the nanostrips, while employing the cyclic boundary conditions to account for their topology. It is found that the dissymmetry factors of twisted graphene nanostrips can reach 0.01, exceeding the typical dissymmetry factors of small chiral molecules by 1-2 orders of magnitude. The results of this work thus demonstrate that twisted graphene nanostrips of Möbius and similar geometries are highly promising nanostructures for chiral optical applications.

Enantioselective Labeling of Zebrafish for D-Phenylalanine Based on Graphene-Based Nanoplatform

Enantioselective labeling of important bioactive molecules in complex biological environments by artificial receptors has drawn great interest. From both the slight difference of enantiomers' physicochemical properties and inherently complexity in living organism point of view, it is still a contemporary challenge for preparing practical chiral device that could be employed in the model animal due to diverse biological interference. Herein, we introduce γ-cyclodextrin onto graphene oxide for fabricating γ-cyclodextrin and graphene oxide assemblies, which provided an efficient nanoplatform for chiral labelling of D-phenylalanine with higher chiral discrimination ratio of KD/KL = 8.21. Significantly, the chiral fluorescence quenching effect of this γ-CD-GO nanoplatform for D-phenylalanine enantiomer in zebrafish was 7.0-fold higher than L-isomer, which exhibiting real promise for producing practical enantio-differentiating graphene-based systems in a complex biological sample.

Demystifying racemic natural products in the homochiral world

Natural products possess structural complexity, diversity and chirality with attractive functions and biological activities that have significantly impacted drug discovery initiatives. Chiral natural products are abundant in nature but rarely occur as racemates. The occurrence of natural products as racemates is very intriguing from a biosynthetic point of view; as enzymes are chiral molecules, enzymatic reactions generating natural products should be stereospecific and lead to single-enantiomer products. Despite several reports in the literature describing racemic mixtures of stereoisomers isolated from natural sources, there has not been a comprehensive review of these intriguing racemic natural products. The discovery of many more natural racemates and their potential enzymatic sources in recent years allows us to describe the distribution and chemical diversity of this 'class of natural products' to enrich discussions on biosynthesis. In this Review, we describe the chemical classes, occurrence and distribution of pairs of enantiomers in nature and provide insights about recent advances in analytical methods used for their characterization. Special emphasis is on the biosynthesis, including plausible enzymatic and non-enzymatic formation of natural racemates, and their pharmacological significance.

Construction and Application of Graphene Oxide-Bovine Serum Albumin Modified Extended Gate Field Effect Transistor Chiral Sensor

Chirality is an essential natural attribute of organisms. Chiral molecules exhibit differences in biochemical processes, pharmacodynamics, and toxicological properties, and their enantioselective recognition plays an important role in explaining life science processes and guiding drug design. Herein, we developed an ultra-sensitive enantiomer recognition platform based on an extended-gate metal-oxide semiconductor field-effect-transistor (Nafion–GO@BSA–EG-MOSFET) that achieved effective chiral resolution of ultra-sensitive Lysine (Lys) and α-Methylbenzylamine (α-Met) enantiodiscrimination at the femtomole level. Bovine serum albumin (BSA) was immobilized on the surface of graphene oxide (GO) through amide bond coupling to prepare the GO@BSA complex. GO@BSA was drop-cast on deposited Au surfaces with a Nafion solution to afford the extended-gate sensing unit. Effective recognition of chiral enantiomers of mandelic acid (MA), tartaric acid (TA), tryptophan (Trp), Lys and α-Met was realized. Moreover, the introduction of GO reduced non-specific adsorption, and the chiral resolution concentration of α-Met reached the level of picomole in a 5-fold diluted fetal bovine serum (FBS). Finally, the chiral recognition mechanism of the as-fabricated sensor was proposed.