Sonochemically modified ovalbumin enhances enantioenrichment of some amino acids

Effects of sound energy on proteins and their complexes

Mechanical energy in the form of ultrasound and protein complexes intuitively have been considered as two distinct unrelated topics. However, in the past few years, increasingly more attention has been paid to the ability of ultrasound to induce chemical modifications on protein molecules that further change protein-protein interaction and protein self-assembling behavior. Despite efforts to decipher the exact structure and the behavior-modifying effects of ultrasound on proteins, our current understanding of these aspects remains limited. The limitation arises from the complexity of both phenomena. Ultrasound produces multiple chemical, mechanical, and thermal effects in aqueous media. Proteins are dynamic molecules with diverse complexation mechanisms. This review provides an exhaustive analysis of the progress made in better understanding the role of ultrasound in protein complexation. It describes in detail how ultrasound affects an aqueous environment and the impact of each effect separately and when combined with the protein structure and fold, the protein-protein interaction, and finally the protein self-assembly. It specifically focuses on modifying role of ultrasound in amyloid self-assembly, where the latter is associated with multiple neurodegenerative disorders.

Designing Natural Polymer-Based Capsules and Spheres for Biomedical Applications-A Review

Natural polymers, such as polysaccharides and polypeptides, are potential candidates to serve as carriers of biomedical cargo. Natural polymer-based carriers, having a core-shell structural configuration, offer ample scope for introducing multifunctional capabilities and enable the simultaneous encapsulation of cargo materials of different physical and chemical properties for their targeted delivery and sustained and stimuli-responsive release. On the other hand, carriers with a porous matrix structure offer larger surface area and lower density, in order to serve as potential platforms for cell culture and tissue regeneration. This review explores the designing of micro- and nano-metric core-shell capsules and porous spheres, based on various functions. Synthesis approaches, mechanisms of formation, general- and function-specific characteristics, challenges, and future perspectives are discussed. Recent advances in protein-based carriers with a porous matrix structure and different core-shell configurations are also presented in detail.

Bio-Catalysis in Multicomponent Reactions

Enzyme catalysis is a very active research area in organic chemistry, because biocatalysts are compatible with and can be adjusted to many reaction conditions, as well as substrates. Their integration in multicomponent reactions (MCRs) allows for simple protocols to be implemented in the diversity-oriented synthesis of complex molecules in chemo-, regio-, stereoselective or even specific modes without the need for the protection/deprotection of functional groups. The application of bio-catalysis in MCRs is therefore a welcome and logical development and is emerging as a unique tool in drug development and discovery, as well as in combinatorial chemistry and related areas of research.

Ultrasonic assisted synthesis of styrylpyridinium dyes: Optical properties and DFT calculations

The ultrasonic technique has received considerable attention in several fields; in particular, it gained rapid momentum in organic synthesis due to the larger reaction rates, milder reaction conditions, and better yields. We report herein a facile synthesis of a series of styrylpyridinium based dyes under ultrasonic irradiation. Within short reaction time (15 min) under ultrasonic irradiation, compared to normal laboratory conditions, (4-16 h), we can achieve good to excellent yields. The reaction time is shortened because ultrasound can accelerate the generation of the nucleophile of the pyridinium salt and subsequently a nucleophilic addition of an aldehyde followed by dehydration affords the styrylpyridinium dye, (Knoevenagel condensation). The photophysical properties of all compounds are comprehensively investigated in different solvents. All the compounds exhibit negative solvatochromism both in absorption and fluorescence emission spectra. Such behavior is due to the higher dipole moment of these molecules at the ground state. DFT calculations were performed to understand the electronic structure of the molecules. Our results show the high efficacy of sonochemistry over other methods for preparation of styrylpyridinium dyes.