Recreating the biological steps of viral infection on a cell-free bioelectronic platform to profile viral variants of concern.

Viral mutations frequently outpace technologies used to detect harmful variants. Given the continual emergence of SARS-CoV-2 variants, platforms that can identify the presence of a virus and its propensity for infection are needed. Our electronic biomembrane sensing platform recreates distinct SARS-CoV-2 host cell entry pathways and reports the progression of entry as electrical signals.

A Pseudo-Surfactant Chemical Permeation Enhancer to Treat Otitis Media via Sustained Transtympanic Delivery of Antibiotics.

Chemical permeation enhancers (CPEs) represent a prevalent and safe strategy to enable noninvasive drug delivery across skin-like biological barriers such as the tympanic membrane (TM). While most existing CPEs interact strongly with the lipid bilayers in the stratum corneum to create defects as diffusion paths, their interactions with the delivery system, such as polymers forming a hydrogel, can compromise gelation, formulation stability, and drug diffusion. To overcome this challenge, differing interactions between CPEs and the hydrogel system are explored, especially those with sodium dodecyl sulfate (SDS), an ionic surfactant and a common CPE, and those with methyl laurate (ML), a nonionic counterpart with a similar length alkyl chain.

Plant Membrane-On-A-Chip: A Platform for Studying Plant Membrane Proteins and Lipids.

The cell plasma membrane is a two-dimensional, fluid mosaic material composed of lipids and proteins that create a semipermeable barrier defining the cell from its environment. Compared with soluble proteins, the methodologies for the structural and functional characterization of membrane proteins are challenging. An emerging tool for studies of membrane proteins in mammalian systems is a "plasma membrane on a chip," also known as a supported lipid bilayer.

Density data for Lake Erie benthic invertebrate assemblages from 1930 to 2019.

Benthic invertebrates are important trophic links in food webs and useful bioindicators of environmental conditions, but long-term benthic organism abundance data across broad geographic areas are rare and historic datasets are often not readily accessible. This dataset provides densities of benthic macroinvertebrates collected from 1930 to 2019 during surveys in Lake Erie, a Laurentian Great Lake. The surveys were funded by the governments of the United States and Canada to investigate the status and changes in the benthic community.

Gram-Positive Bacterial Membrane-Based Biosensor for Multimodal Investigation of Membrane-Antibiotic Interactions.

As membrane-mediated antibiotic resistance continues to evolve in Gram-positive bacteria, the development of new approaches to elucidate the membrane properties involved in antibiotic resistance has become critical. Membrane vesicles (MVs) secreted by the cytoplasmic membrane of Gram-positive bacteria contain native components, preserving lipid and protein diversity, nucleic acids, and sometimes virulence factors. Thus, MV-derived membrane platforms present a great model for Gram-positive bacterial membranes.

An Impedance-Based Approach for Sensing Cyclodextrin-Mediated Modulation of Membrane Cholesterol.

Cyclodextrin molecules are increasingly being used in biological research and as therapeutic agents to alter membrane cholesterol content, yet there is much to learn about their interactions with cell membranes. We present a biomembrane-based organic electronic platform capable of detecting interactions of cell membrane constituents with methyl-β-cyclodextrin (MβCD). This approach enables label-free sensing and quantification of changes in membrane integrity resulting from such interactions.

Hybrid Supported Lipid Bilayers for Bioinspired Bioelectronics with Enhanced Stability.

A promising new class of biosensors leverages the sensing mechanisms of living cells by incorporating native transmembrane proteins into biomimetic membranes. Conducting polymers (CPs) can further improve the detection of electrochemical signals from these biological recognition elements through their low electrical impedance. Supported lipid bilayers (SLBs) on CPs mimic the structure and biology of the cell membrane to enable such sensing, but their extrapolation to new target analytes and healthcare applications has been difficult due to their poor stability and limited membrane properties.

Membrane protein synthesis: no cells required.

Despite advances in membrane protein (MP) structural biology and a growing interest in their applications, these proteins remain challenging to study. Progress has been hindered by the complex nature of MPs and innovative methods will be required to circumvent technical hurdles. Cell-free protein synthesis (CFPS) is a burgeoning technique for synthesizing MPs directly into a membrane environment using reconstituted components of the cellular transcription and translation machinery in vitro.

Single Particle Analysis of H3N2 Influenza Entry Differentiates the Impact of the Sialic Acids (Neu5Ac and Neu5Gc) on Virus Binding and Membrane Fusion.

Entry of influenza A viruses (IAVs) into host cells is initiated by binding to sialic acids (Sias), their primary host cell receptor, followed by endocytosis and membrane fusion to release the viral genome into the cytoplasm of the host cell. Host tropism is affected by these entry processes, with a primary factor being receptor specificity. Sias exist in several different chemical forms, including the hydroxylated N-glycolylneuraminic acid (Neu5Gc), which is found in many hosts; however, it has not been clear how modified Sias affect viral binding and entry.

Cell-Free Synthesis Goes Electric: Dual Optical and Electronic Biosensor via Direct Channel Integration into a Supported Membrane Electrode.

Assembling transmembrane proteins on organic electronic materials is one promising approach to couple biological functions to electrical readouts. A biosensing device produced in such a way would enable both the monitoring and regulation of physiological processes and the development of new analytical tools to identify drug targets and new protein functionalities. While transmembrane proteins can be interfaced with bioelectronics through supported lipid bilayers (SLBs), incorporating functional and oriented transmembrane proteins into these structures remains challenging.

Interactions of SARS-CoV-2 and MERS-CoV fusion peptides measured using single-molecule force methods.

We address the challenge of understanding how hydrophobic interactions are encoded by fusion peptide (FP) sequences within coronavirus (CoV) spike proteins. Within the FPs of severe acute respiratory syndrome CoV 2 and Middle East respiratory syndrome CoV (MERS-CoV), a largely conserved peptide sequence called FP1 (SFIEDLLFNK and SAIEDLLFDK in SARS-2 and MERS, respectively) has been proposed to play a key role in encoding hydrophobic interactions that drive viral-host cell membrane fusion. Although a non-polar triad (Leu-Leu-Phe (LLF)) is common to both FP1 sequences, and thought to dominate the encoding of hydrophobic interactions, FP1 from SARS-2 and MERS differ in two residues (Phe 2 versus Ala 2 and Asn 9 versus Asp 9, respectively).

Six decades of Lake Ontario ecological history according to benthos.

The Laurentian Great Lakes have experienced multiple anthropogenic changes in the past century, including cultural eutrophication, phosphorus abatement initiatives, and the introduction of invasive species. Lake Ontario, the most downstream lake in the system, is considered to be among the most impaired. The benthos of Lake Ontario has been studied intensively in the last six decades and can provide insights into the impact of environmental changes over time.

Spike Protein Cleavage-Activation in the Context of the SARS-CoV-2 P681R Mutation: an Analysis from Its First Appearance in Lineage A.23.1 Identified in Uganda.

Based on its predicted ability to affect transmissibility and pathogenesis, surveillance studies have highlighted the role of a specific mutation (P681R) in the S1/S2 furin cleavage site of the SARS-CoV-2 spike protein. Here we analyzed A.23.

Nanoscale Features of Tunable Bacterial Outer Membrane Models Revealed by Correlative Microscopy.

The rise of antibiotic resistance is a growing worldwide human health issue, with major socioeconomic implications. An understanding of the interactions occurring at the bacterial membrane is crucial for the generation of new antibiotics. Supported lipid bilayers (SLBs) made from reconstituted lipid vesicles have been used to mimic these membranes, but their utility has been restricted by the simplistic nature of these systems.

Bioelectronic Platform to Investigate Charge Transfer between Photoexcited Quantum Dots and Microbial Outer Membranes.

Photosynthetic semiconductor biohybrids (PSBs) convert light energy to chemical energy through photo-driven charge transfer from nanocrystals to microorganisms that perform bioreactions of interest. Initial proof-of-concept PSB studies with an emphasis on enhanced CO conversion have been encouraging; however, bringing the broad prospects of PSBs to fruition is contingent on establishing a firm fundamental understanding of underlying interfacial charge transfer processes. We introduce a bioelectronic platform that reduces the complexity of PSBs by focusing explicitly on interactions between colloidal quantum dots (QDs), microbial outer membranes, and native, small-molecule redox mediators.

Small tools for sweet challenges: advances in microfluidic technologies for glycan synthesis.

Glycans, including oligosaccharides and glycoconjugates, play an integral role in modulating the biological functions of macromolecules. Many physiological and pathological processes are mediated by interactions between glycans, which has led to the use of glycans as biosensors for pathogen and biomarker detection. Elucidating the relationship between glycan structure and biological function is critical for advancing our understanding of the impact glycans have on human health and disease and for expanding the repertoire of glycans available for bioanalysis, especially for diagnostics.

Is contact-line mobility a material parameter?

Dynamic wetting phenomena are typically described by a constitutive law relating the dynamic contact angle θ to contact-line velocity U. The so-called Davis-Hocking model is noteworthy for its simplicity and relates θ to U through a contact-line mobility parameter M, which has historically been used as a fitting parameter for the particular solid-liquid-gas system. The recent experimental discovery of Xia & Steen (2018) has led to the first direct measurement of M for inertial-capillary motions.

Impedance sensing of antibiotic interactions with a pathogenic E. coli outer membrane supported bilayer.

Antibiotic resistance is a growing global health concern due to the decreasing number of antibiotics available for therapeutic use as more drug-resistant bacteria develop. Changes in the membrane properties of Gram-negative bacteria can influence their response to antibiotics and give rise to resistance. Thus, understanding the interactions between the bacterial membrane and antibiotics is important for elucidating microbial membrane properties to use for designing novel antimicrobial drugs.

Cell-Free Synthesis of a Transmembrane Mechanosensitive Channel Protein into a Hybrid-Supported Lipid Bilayer.

Supported lipid bilayers (SLBs) hold tremendous promise as cellular-mimetic structures that can be readily interfaced with analytical and screening tools. The incorporation of transmembrane proteins, a key component in biological membranes, is a significant challenge that has limited the capacity of SLBs to be used for a variety of biotechnological applications. Here, we report an approach using a cell-free expression system for the cotranslational insertion of membrane proteins into hybrid-supported lipid bilayers (HSLBs) containing phospholipids and diblock copolymers.

Glycosylation-on-a-Chip: A Flow-Based Microfluidic System for Cell-Free Glycoprotein Biosynthesis.

In recent years, cell-free synthetic glycobiology technologies have emerged that enable production and remodeling of glycoproteins outside the confines of the cell. However, many of these systems combine multiple synthesis steps into one pot where there can be competing reactions and side products that ultimately lead to low yield of the desired product. In this work, we describe a microfluidic platform that integrates cell-free protein synthesis, glycosylation, and purification of a model glycoprotein in separate compartments where each step can be individually optimized.

Functional evaluation of the P681H mutation on the proteolytic activation of the SARS-CoV-2 variant B.1.1.7 (Alpha) spike.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent causing the COVID-19 pandemic. SARS-CoV-2 B.1.