Self-assembly Of Lipid Bilayers Research Articles

A ratiometric electrochemical biosensor for analysis of total N-glycolylneuraminic acid based on pH-adjusted self-assembly of lipid bilayer

In this work, we propose a pH-adjusted self-assembled lipid bilayer (LB) as signal output mode for the analysis of total N-glycolylneuraminic acids (TNeu5Gc) including free Neu5Gc and conjugated Neu5Gc. Based on synergistic inhibition effect of pH-adjusted self-assembled LB and TNeu5Gc on transport of hydrophilic probe, a ratiometric electrochemical biosensor has been elaborately constructed to decrease the experimental interferences and enhance analytical accuracy. The constructed biosensor has been successfully applied for electrochemical analysis of TNeu5Gc with a wide linear detection range from 2.816 ng/mL to 360.396 ng/mL and a low detection limit of 0.506 ng/mL. This work not only firstly establishes a ratiometric electrochemical biosensor for the analysis of TNeu5Gc, but also provides a new insight for self-assembly of LB in response to pH value change.

Electrochemical Analysis of Enzyme Based on the Self-Assembly of Lipid Bilayer on an Electrode Surface Mediated by Hydrazone Chemistry.

In this work, a new strategy for electrochemical analysis of enzyme has been proposed based on a self-assembled lipid bilayer on an electrode surface mediated by hydrazone chemistry. Taking aldolase as an example, the enzyme can catalyze the formation of products containing carbonyl groups. These groups can react with hydrazine groups of the functional lipid derivative, resulting in the self-assembly of a lipid bilayer on a guanidinium modified electrode surface. The lipid bilayer will then prevent the movement of hydrophilic electrochemical probes. Consequently, the catalytic reaction of the enzyme may result in the change of the obtained electrochemical peak current. Experimental results reveal that aldolase activity can be analyzed over a widely linear detection range from 5 mU/L to 100 U/L with a low detection limit of 1 mU/L. Meanwhile, the method can exhibit good precision and reproducibility and it can be applied for real sample analysis. What is more, because the lipid bilayer is the universal basis for cell-membrane structure, while hydrazone chemistry is popular in nature, this work may also provide a new insight for the development of electrochemical analysis and electrochemical biosensors.

Exploring new frontiers in statistical physics with a new, parallel Wang-Landau framework

Combining traditional Wang-Landau sampling for multiple replica systems with an exchange of densities of states between replicas, we describe a general framework for simulations on massively parallel Petaflop supercomputers. The advantages and general applicability of the method for simulations of complex systems are demonstrated for the classical 2D Potts spin model featuring a strong first-order transition and the self-assembly of lipid bilayers in amphiphilic solutions in a continuous model.

Artificial envelopment of nonenveloped viruses: enhancing adenovirus tumor targeting in vivo

Recombinant adenovirus (Ad) is a powerful tool in gene therapy. However, the ability to deliver Ad by systemic administration is limited due to rapid clearance from blood circulation, transfection of nontarget tissues, toxicity, and immunogenicity. To address these limitations, we developed an artificially enveloped Ad vector prepared by self-assembly of lipid bilayers around the Ad capsid. The physicochemical and structural features of the enveloped Ad vector can be altered according to the type of lipid used without the need for genetic modification or conjugation chemistry. Here we engineered 4 different types of artificially enveloped Ad using cationic, neutral, fusogenic, and PEGylated lipids to form the envelopes and obtained extended blood circulation times following i.v. administration and reduced vector immunogenicity. Moreover, the PEGylated lipid-enveloped Ad was capable of specifically delivering genes via the systemic circulation to solid tumors subcutaneously implanted in the absence of high levels of gene transfer to the liver and spleen. This provides the basis for the development of a novel vector platform for systemic delivery of Ad to disseminated targets. Furthermore, the artificial envelopment of Ad presented herein is an illustration of a general strategy to modulate the biological function of nonenveloped viruses and may have implications broader than gene therapy.