Small Surfactant Concentration Differences Influence Adsorption of Human Serum Albumin on Polystyrene Nanoparticles

Surfactants, even in miniscule amounts, are often used for the synthesis and especially the stabilization of nanomaterials, which is essential for in vivo applications. In this study, we show that the interaction between nanoparticles and proteins strongly depends on the type of stabilizing surfactants and their (small) concentration changes. The reaction between human serum albumin and polystyrene nanoparticles stabilized by an ionic or nonionic surfactantsodium dodecyl sulfate or Lutensol AT50, respectivelywas monitored using isothermal titration calorimetry. It was found that the amount of surfactant molecules on the surface significantly determines the protein binding affinity and adsorption stoichiometry, which is important for all nanomaterials coming into contact with biological components such as blood plasma proteins. Thus after synthesizing nanomaterials for in vivo applications as drug delivery agents, it is crucial to perform a detailed analysis of the obtained surface chemistry that accounts for the presence of minimal amounts of stabilizing agents

Denaturation via Surfactants Changes Composition of Protein Corona

The use of nanocarriers as drug delivery vehicles brings them into contact with blood plasma proteins. Polymeric nanocarriers require some sort of surfactant to ensure colloidal stability. Formation of the protein corona is therefore determined not only by the intrinsic properties of the nanocarrier itself but also by the accompanying surfactant. Although it is well-known that surfactants have an impact on protein structure, only few studies were conducted on the specific effect of surfactants on the composition of protein corona of nanocarriers. Therefore, we analyzed the composition of the protein corona on “stealth” nanoparticles with additional surfactant (cetyltrimethyl­ammonium chloride, CTMA-Cl) after plasma incubation. Additional CTMA-Cl led to an enrichment of apolipoprotein-A1 and vitronectin in the corona, while less clusterin could be found. Further, the structural stability of apolipoprotein-A1 and clusterin was monitored for a wide range of CTMA-Cl concentrations. Clusterin turned out to be more sensitive to CTMA-Cl, with denaturation occurring at lower concentrations

Denaturation via Surfactants Changes Composition of Protein Corona

The use of nanocarriers as drug delivery vehicles brings them into contact with blood plasma proteins. Polymeric nanocarriers require some sort of surfactant to ensure colloidal stability. Formation of the protein corona is therefore determined not only by the intrinsic properties of the nanocarrier itself but also by the accompanying surfactant. Although it is well-known that surfactants have an impact on protein structure, only few studies were conducted on the specific effect of surfactants on the composition of protein corona of nanocarriers. Therefore, we analyzed the composition of the protein corona on “stealth” nanoparticles with additional surfactant (cetyltrimethyl­ammonium chloride, CTMA-Cl) after plasma incubation. Additional CTMA-Cl led to an enrichment of apolipoprotein-A1 and vitronectin in the corona, while less clusterin could be found. Further, the structural stability of apolipoprotein-A1 and clusterin was monitored for a wide range of CTMA-Cl concentrations. Clusterin turned out to be more sensitive to CTMA-Cl, with denaturation occurring at lower concentrations

Combining Solar Steam Processing and Solar Distillation for Fully Off-Grid Production of Cellulosic Bioethanol

Conventional bioethanol for transportation fuel typically consumes agricultural feedstocks also suitable for human consumption and requires large amounts of energy for conversion of feedstock to fuel. Alternative feedstocks, optimally those not also in demand for human consumption, and off-grid energy sources for processing would both contribute to making bioethanol far more sustainable than current practices. Cellulosic bioethanol production involves three steps: the extraction of sugars from cellulosic feedstock, the fermentation of sugars to produce ethanol, and the purification of ethanol through distillation. Traditional production methods for extraction and distillation are energy intensive and therefore costly, limiting the advancement of this approach. Here we report an initial demonstration of the conversion of cellulosic feedstock into ethanol by completely off-grid solar processing steps. Our approach is based on nanoparticle-enabled solar steam generation, in which high-efficiency steam can be produced by illuminating light-absorbing nanoparticles dispersed in H₂O with sunlight. We used solar-generated steam to successfully hydrolyze feedstock into sugars; we then used solar steam-distillation to purify ethanol in the final processing step. Coastal hay, a grass grown for livestock feed across the southern United States, and sugar cane as a control are successfully converted to ethanol in this proof-of-concept study. This entirely off-grid solar production method has the potential to realize the long-dreamed-of goal of sustainable cellulosic bioethanol production