Cooperative Self-Assembly of Helical Exciton-Coupled Biosurfactant-Functionalized Porphyrin Chromophores

Anthracenemethyl Glycosides as Supramolecular Synthons for Chiral Self-Assembly and as Probes in Cell Imaging

Chiral self-assembly of molecules warrants optimal structural features of synthons that promote formation of such self-assembled structures. A polyaromatic moiety coupled with hydrophilic, chiral-rich carbohydrates leads to segmentation of the regions and the self-assembly to supramolecular structures. Thermodynamic stability is augmented further through chiral self-assembly of the molecules, and formation of the desired chiral supramolecular structures is achieved. In the present study, we develop anthracene glycosides as efficient synthons that, in aqueous solutions, undergo facile self-assembly and lead to chiral supramolecular structures. Anthracenemethyl O-glycosides, installed with mono- and disaccharides, are studied for their self-assembly properties. Emerging chiral structures follow the configuration of the attached sugar moiety. Monosaccharide d- and l-glycopyranoside-containing derivatives alternate between left- and right-handed chiral structures, respectively. Disaccharide-containing derivatives do not exhibit chirality, even when self-assembly occurred. Photochemical [4π + 4π] cycloaddition occurs in the self-assembled structure in aqueous solution. Cell viability assay using HeLa cells shows above 80% viable cells at a concentration of 50 μM. Bioimaging assays reveal a significant imaging of HeLa cells for anthracenemethyl d-glucopyranoside; bright imaging was observed at the perinuclear region of the cells, suggestive of an active transport of the molecules through the cell membrane. d-Galactopyranoside and l-glucopyranoside-containing derivatives show weak imaging potencies.

Tuning the Chiral Structures from Self-Assembled Carbohydrate Derivatives

Carbohydrates have been regarded as one of the most ideally suited candidates for chirality study via self-assembly owning to their unique chemical structures, abundance, and sustainability. Much efforts have been devoted to design and synthesize diverse carbohydrate derivatives and self-assemble them into various supermolecular morphologies. Nevertheless, still inadequate attention is paid to deeply and comprehensively understand how the carbohydrate structures and self-assembly approaches affect the final morphologies and properties for future demands. Herein, to fulfill the need, a range of recently published studies relating to the chirality of carbohydrates is reviewed and discussed. Furthermore, to tune the chirality of carbohydrate-based structures on both molecular and superstructural levels via chirality transfer and chirality expression, the designing of the molecules and choosing of the proper approaches for self-assembly are elucidated.

Lyotropic Liquid-Crystalline Phases of Sophorolipid Biosurfactants

Biological amphiphiles derived from natural resources are presently being investigated in the hope that they will someday replace current synthetic surfactants, which are known pollutants of soils and water resources. Sophorolipids constitute one of the main classes of glycosylated biosurfactants that have attracted interest because they are synthesized by non-pathogenic yeasts from glucose and vegetable oils at high titers. In this work, the self-assembly properties of several sophorolipids in water at high concentrations (20-80 wt %), a range so far mostly uncharted, have been investigated by polarized-light microscopy and X-ray scattering. Some of these compounds were found to show lyotropic liquid-crystalline behavior as they display lamellar or hexagonal columnar mesophases. X-ray scattering data shows that the structure of the lamellar phase is almost fully interdigitated, which is likely due to the packing difference between the bulky hydrophilic tails and the more compact aliphatic chains. A tentative representation of the molecular organization of the columnar phase is also given. Moreover, some of these compounds display thermotropic liquid-crystalline behavior, either pure or in aqueous mixtures. In addition, small domains of the lamellar phase can easily be aligned by applying onto them a moderate a.c. electric field, which is a rather unusual feature for lyotropic liquid crystals. Altogether, our work explored the self-assembly liquid-crystalline behavior of sophorolipids at high concentration, which could shed light on the conditions of their potential industrial applications as well as on their biological function.

From bumblebee to bioeconomy: Recent developments and perspectives for sophorolipid biosynthesis

Sophorolipids are biobased compounds produced by the genera Starmerella and Pseudohyphozyma that gain exponential interest from academic and industrial stakeholders due to their mild and environmental friendly characteristics. Currently, industrially relevant sophorolipid volumetric productivities are reached up to 3.7 g∙L^-1∙h^-1 and sophorolipids are used in the personal care and cleaning industry at small scale. Moreover, applications in crop protection, food, biohydrometallurgy and medical fields are being extensively researched. The research and development of sophorolipids is at a crucial stage. Therefore, this work presents an overview of the state-of-the-art on sophorolipid research and their applications, while providing a critical assessment of scientific techniques and standardisation in reporting. In this review, the genuine sophorolipid producing organisms and the natural role of sophorolipids are discussed. Subsequently, an evaluation is made of innovations in production processes and the relevance of in-situ product recovery for process performance is discussed. Furthermore, a critical assessment of application research and its future perspectives are portrayed with a focus on the self-assembly of sophorolipid molecules. Following, genetic engineering strategies that affect the sophorolipid physiochemical properties are summarised. Finally, the impact of sophorolipids on the bioeconomy are uncovered, along with relevant future perspectives.

The Assembly of Porphyrin Systems in Well-Defined Nanostructures: An Update

The interest in assembling porphyrin derivatives is widespread and is accounted by the impressive impact of these suprastructures of controlled size and shapes in many applications from nanomedicine and sensors to photocatalysis and optoelectronics. The massive use of porphyrin dyes as molecular building blocks of functional materials at different length scales relies on the interdependent pair properties, consisting of their chemical stability/synthetic versatility and their quite unique physicochemical properties. Remarkably, the driven spatial arrangement of these platforms in well-defined suprastructures can synergically amplify the already excellent properties of the individual monomers, improving conjugation and enlarging the intensity of the absorption range of visible light, or forming an internal electric field exploitable in light-harvesting and charge-and energy-transport processes. The countless potentialities offered by these systems means that self-assembly concepts and tools are constantly explored, as confirmed by the significant number of published articles related to porphyrin assemblies in the 2015-2019 period, which is the focus of this review.