Current Opinion in Colloid & Interface Science最新文献

The public increasingly requests green formulations as a consequence of growing sustainability awareness. This may include glycolipid and lipopeptide biosurfactants (BS), which are considered renewable, biodegradable, and mild alternatives to conventional fossil-based surfactants. For developing green formulations, it is crucial to understand the phase behavior and the resulting physico-chemical characteristics of systems with BS. This is not only necessary for binary systems of BS in water, which have already been frequently studied and reviewed. But it is also important to study combinations with other surfactants and oils due to their higher relevance for applications. For this reason, we review in this article the different types of phase behavior of systems comprising BS, in particular systems with rhamnolipid, sophorolipid, mannosylerythritol lipid, cellobiose lipid, and surfactin.

Synergies between surfactants and proteins are found everywhere in everyday life. Beneficial interactions are exploited in fields such as food processing, pharmaceutical production, and laundry, leading to better products and lower energy consumption. Nevertheless, there is still room for improvement regarding sustainability. Here, biosurfactants (BS) are an attractive alternative to petrochemical surfactants. Insights into BS-protein interactions can help replacing traditional surfactants with BS and uncover new opportunities. Here, we review recent work on proteins' interactions with BS, with focus on the self-assembly of protein:BS complexes and BS’ effects on enzymatic activity. Generally, interactions are milder than those with traditional ionic surfactants, leading to modest effects on protein structure and self-assembly, while enzymatic inhibition is generally observed above BS' critical micelle concentration. Mild interactions between proteins and BS show promise in forming functional complexes with proteins, however, further studies are required to understand and minimize the detrimental effects that do occur.

Physics-based molecular simulation is a potentially transformative tool in the field of biosurfactants. Years of research and software development have culminated in reliable and accessible techniques for applying simulation to a variety of research problems. Simulation tools can be used to probe a wide range of atomic-scale phenomena from single molecule conformational behavior to large scale aggregation in solution and at interfaces. In recent years, researchers are increasingly finding ways to incorporate insights from molecular simulation into biosurfactant research. In this review, we highlight recent advances in simulation of biosurfactants, with discussion centered on the role of all-atom and coarse-grained molecular dynamics as well as some discussion of quantum mechanics. We also offer perspective on the future of biosurfactant simulation where we consider ways to improve the practical usefulness of simulation results as well as the most effective way to leverage simulation for faster and truly novel innovation.

Microbial biosurfactants have gained interest in the last decades because of their unique characteristics. The variety of chemical structures within these compounds makes them very versatile, with glycolipids and lipopeptides outstanding among the rest. The amphiphilic nature of these compounds makes them to partition into and strongly interact with phospholipid membranes, modifying their structure and function. Thus, much research has been done on the characterization of the interaction of glycolipid and lipopeptide biosurfactants with model and biological membranes. Whereas the studies involving phospholipid model membranes were mostly carried out earlier, most of the recent research has focused on biological membranes, including mammalian and microorganisms' systems. This review presents the recent developments achieved on the interaction of the main glycolipid and lipopeptide biosurfactants with model and biological membranes.

Due to their environmental benefits and rich interfacial and colloidal properties, biosurfactants show promise as a platform for next-generation reagents in metal extraction using froth and foam flotation. While the development of biosurfactants as flotation bioreagents is still in its infancy, it has witnessed important progress in the past five years. Recent studies have not only demonstrated the ability of biosurfactants to compete with conventional collectors but have also provided valuable insights into the experimental parameters affecting these two separation processes. Despite this progress, the interactions of biosurfactants with mineral particles, metal ions, and air bubbles under flotation conditions remain far from being fully understood. There is growing evidence suggesting that these interactions are more complex than observed for conventional petroleum-based collectors. We summarize the recent progress and outline the main remaining knowledge gaps, aiming to generate more interest in the intriguingly complex multifunctional properties of biosurfactants as collectors.

New surfactants are not necessarily better than established surfactants; new surfactants need to be better, cheaper or have a lower environmental impact to have an advantage over existing products. Attributes like aquatoxicity, mildness, sourcing from renewable carbon and emissions of greenhouse gases during production and use of surfactants had become more and more important. Biosurfactants (BS) which are not really new to the world but which have been so far only produced at low concentrations by microorganisms or plants have attained attention in academical research and interest of industry in the last 25 years resulting in the commercial availability of Sophorolipids and Rhamnolipids by several companies. BS are dedicated to applications in PersonalCare and HouseHold Care due to their consumer-recognizable mildness; BS can, however, not simply replace established components in formulations due to their different performance profile, which makes comparison to traditional surfactants rather complicated.

The dispersion of small particles provides an inexpensive and convenient way to significantly improve various functional properties of the base fluid. Nanodispersions can be used to solve various industrial and technical problems, such as increasing the efficiency of heat generating systems, cooling electrical equipment, water desalination, control of thermal regimes of chemical processes and electronic devices, enhancing oil recovery, and so on. This review targets to highlight the recently published results that are of general importance for understanding the processes occurring during wetting and spreading of nanofluids over various surfaces, as well as the mechanisms that determine these processes.

This review provides an overview of experimental and computational results on the interaction between nanocarriers of different natures and pulmonary surfactant models that have appeared in the literature in the last five years. The purpose is to highlight the changes in the nanoscopic structure and functionality of the pulmonary surfactant layer due to the interaction with nanocarriers and nanoparticles, which are inorganic, polymeric, or consist of biomolecules. The information gathered contributes to the development of carriers' nanotechnology, thus allowing specific and controlled drug delivery while being minimally invasive by crossing pulmonary surfactant without altering its structure and function.

The upper layer of our skin, the stratum corneum (SC), is a versatile material that combines mechanical strength with efficient barrier function. In this paper, we discuss these macroscopic properties of SC in relation to recent findings on molecular responses and structural diversity in SC protein and lipids. We put particular focus on the intermediate (colloidal) length scale and how the different SC substructures are organized with respect to each other, including effects of non-equilibrium conditions in the skin with respect to the gradients in water and other components.

Biopolymer hydrogel particles provide a wide range of advantages to food applications due to their highly hydrophilic nature, the ability to tailor micro-/macro-structure, and their complex rheology as dispersions. In food, dispersions of cross-linked hydrogel particles are increasingly used to create unique appearances or textures, novel aroma experiences, and/or for controlled-release applications. Mastering food biopolymer particle dispersions requires understanding of biopolymer physicochemistry, controlled microstructure creation, particle interactions that govern flow behavior, and the characterization techniques that give insight into the structure-function relationships across the different length scales. In the present review, recent progress in cross-linked food biopolymer hydrogels across these domains is presented with a particular focus on fluid gel dispersions and controlled release. We highlight how emerging technologies/techniques might enable new microstructural understanding or designer biopolymer sequences. Finally, we highlight how these developments help to fully unlock biopolymer hydrogel dispersions for food applications.