Dynamic macromolecular material design: the versatility of cucurbituril over cyclodextrin in host-guest chemistry.

The keto-enol tautomerism of avobenzone (AVO) is pivotal to its photostability, influenced by microenvironmental factors, such as, the type of solvent and complexation with macrocyclic compounds. This study explores the effect of host-guest complexation on AVO photostabilization, employing cucurbit[7]uril (CB[7]) and ß-cyclodextrin (ß-CD) to form inclusion complexes. CB[7] exhibits a higher affinity to the keto form of AVO, a UVC radiation absorber. The complexed keto form facilitates the regeneration of the enol form, reducing skin permeation. Spectroscopic and thermal analyses confirm 1 : 1 AVO-CB[7] and AVO-ß-CD complex formation. Computational and MD simulations show that host-guest complex is favored over isolated AVO and ß-CD or CB[7] molecules by 95-125 kJ mol-1, depending on the presence of implicit solvent. Both macrocycles enhance AVO photostabilization in aqueous environments, with CB[7] displaying greater selectivity for the keto form, while ß-CD shows ethanol concentration-dependent binding.

A novel inclusion complex of oxybenzone with C-methylresorcin[4]arene deters skin permeation.

Oxybenzone (OXB), a very widely used sunscreen ingredient has the potential to block both UVA and UVB but can penetrate through skin. Studies have revealed its presence in the blood and urine of most humans, which may lead to long-term health effects. As the confined cavities of macrocycles can alter the physical and chemical properties of encapsulated guests, in this study, we investigated the formation of host-guest complexes between C-methylresorcin[4]arene and OXB. Combined experimental (NMR spectroscopy, UV/vis absorption, and fluorescence spectroscopy) and theoretical investigation confirmed the formation of a weak host-guest complex that had a 1 : 1 stoichiometry. Furthermore, skin permeation testing revealed that complexation by C-methylresorcin[4]arene significantly reduced the skin permeation of OXB which can potentially limit the harmful effects of this organic sunscreen.

Rational Design and Construction of Hierarchical Superstructures Using Shape-Persistent Organic Cages: Porphyrin Box-Based Metallosupramolecular Assemblies.

We report a new approach to building hierarchical superstructures using a shape-persistent porous organic cage, which acts as a premade secondary building unit, and coordination chemistry. To illustrate the principle, a zinc-metalated porphyrin box (Zn-PB), a corner-truncated cubic porous cage, was connected by suitable dipyridyl terminated bridging ligands to construct PB-based hierarchical superstructures (PSSs). The PSSs were stabilized not only by the coordination bonds between Zn ions and bipyridyl-terminated ligands but also by π-π interactions between the corners of the Zn-PB units. By varying the length of the linker, we identified an optimum range of the linker length for construction of PSSs. The PSSs have large void volumes and an extrinsic surface area compared to the parent PBs, which can be exploited for the selective encapsulation and interior functionalization of the PSSs for various applications, including catalysis. We observed that singlet oxygen induced synthesis of the natural product, juglone, is more efficiently catalyzed by PSS-1 than its constituent component Zn-PB.

CRISPR/Cas approach: A new way of looking at plant-abiotic interactions.

It is not the most grounded of the species that survive, nor the most shrewd, however one most receptive to change. Crop plants being sessile are subjected to various abiotic stresses resulting significant yield losses about an average of more than 50 percent, thus greatly threatening the global crop production. In this regard, plant breeding innovations and genetic engineering approaches have been used in the past for generating stress tolerant crop genotypes, but due to complex inheritance of abiotic stress tolerance these approaches are not enough to bring significant trait improvement and to guarantee world's future sustenance security. Although, RNA interference (RNAi) technology has been utilized amid the most recent decades to produce plants tolerant to environmental stress. But this technique ordinarily prompts to down-regulate as opposed to complete inhibition of target genes. Therefore, scientist/researchers were looking for techniques that should be efficient, precise and reliable as well as have potential to solve the issues experienced by previous approaches, and hence the CRISPR/Cas system came into spotlight. Although, only few studies using CRISPR/Cas approach for targeting abiotic stress tolerance related genes have been reported, but suggested its effective role for future applications in molecular breeding to improve abiotic stress tolerance. Hence, genome engineering via CRISPR-Cas system for targeted mutagenesis promise its immense potential in generating elite cultivars of crop plants with enhanced and durable climate resilience. Lastly, CRISPR-Cas will be future of crop breeding as well as to target minor gene variation of complex quantitative traits, and thus will be the key approach to release global hunger and maintain food security.