The channel activity of gramicidin A in free-standing planar lipid bilayers with different charges of polar head groups and various lengths of hydrocarbon tails were analyzed in terms of the channel conductance, the lifetime of channel events and the magnitude of integrated currents. The channel activity of gramicidin A in lipid bilayers is tunable by adjusting the membrane composition. The in situ coupling of the anti-BSA antibody as a model protein to the amine moiety of phosphatidylethanolamine (PE) in a lipid bilayer by the amine coupling method allowed us to design an antigen (BSA)-sensitive interface, in which the integrated current, rather than the frequency of channel event, can be used as an analytical signal. The potential of the present system for highly sensitive and selective detection of BSA at 10(-9) g/mL level is demonstrated.
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http://dx.doi.org/10.2116/analsci.28.661 | DOI Listing |
Langmuir
January 2025
Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, United States.
Biological memory is the ability to develop, retain, and retrieve information over time. Currently, it is widely accepted that memories are stored in synapses (i.e.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States.
Modification of silica interfaces by covalent attachment of functional ligands is a primary means of controlling the interfacial chemistry of porous silicas used in separations, environmental cleanup, and biosensing. Recently, modification of hydrophobic, -alkyl-silane-functionalized interfaces has been achieved through self-assembly of zwitterionic phospholipids or mixed-charged surfactants to form "hybrid bilayers", producing interfaces that mimic lipid-bilayer partitioning and provide shape-selective partitioning of aromatic hydrocarbons. Charged headgroups, however, introduce electrostatic interactions that strongly influence the retention of ionizable solutes and require careful control over pH and ionic strength in the solution phase.
View Article and Find Full Text PDFLangmuir
January 2025
School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Alkylphospholipids are single-chain lipid amphiphiles that possess clinically relevant biological activities driven by membrane-destabilizing interactions. Subtle variations in alkylphospholipid structure can lead to significant differences in their biological effects, yet corresponding membrane interactions remain underexplored. Herein, we employed the quartz crystal microbalance-dissipation (QCM-D) technique to characterize the real-time membrane interactions of three alkylphospholipids-edelfosine, miltefosine, and perifosine-on supported lipid bilayers with varying cholesterol fractions.
View Article and Find Full Text PDFFEBS Open Bio
January 2025
Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany.
Neurotransmitter release is triggered in microseconds by the two C domains of the Ca sensor synaptotagmin-1 and by SNARE complexes, which form four-helix bundles that bridge the vesicle and plasma membranes. The synaptotagmin-1 CB domain binds to the SNARE complex via a 'primary interface', but the mechanism that couples Ca-sensing to membrane fusion is unknown. Widespread models postulate that the synaptotagmin-1 Ca-binding loops accelerate membrane fusion by inducing membrane curvature, perturbing lipid bilayers or helping bridge the membranes, but these models do not seem compatible with SNARE binding through the primary interface, which orients the Ca-binding loops away from the fusion site.
View Article and Find Full Text PDFNeuron
January 2025
Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address:
Neurexin cell-adhesion molecules regulate synapse development and function by recruiting synaptic components. Here, we uncover a mechanism for presynaptic assembly that precedes neurexin recruitment, mediated by interactions between cytosolic proteins and membrane phospholipids. Developmental imaging in C.
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