Final Report Summary - NMU-LIPIDS (Biomimetic Lipid Structures on Nano- and Microfluidic Platforms)
Lipid membranes are essential for life and a key element for cellular organization. Membranes form compartments to keep molecules within the lumen, but also the transport of molecules is enabled across the membranes via passive permeation or active processes. One of the peculiar properties of membranes is the ability to form various morphologies. The goal of the nµLIPID project was to develop new approaches for the defined engineering of cellular membranes of different shapes and composition based on microfluidics technology. Moreover, the microfluidic platforms facilitated the analysis of these membranes to gain new insights into the properties of membranes including fusion and fission of membranes. The unique properties of membranes were exploited e.g. in the field of membrane-based sensors. The projects addressed both engineering aspects and applied studies.
Within the nµLIPID project, microfluidic devices were developed to form spherical structures (vesicles) and tubular structures by various techniques, including hydrodynamic focusing and micro-extrusion. Furthermore, we found solutions to immobilize and analyze the lipid membrane structures by shock-freezing, implementing trapping features to capture one or more large or giant vesicles, using chemical surface patterns to tether small vesicles and implementing tips to immobilize tubular structures.
These new platforms were employed in several studies, aiming at (i) fundamental understanding of membrane properties and membrane fusion, (ii) applications toward the engineering of complex artificial cells and (iii) the exploitation of the methods for sensors and analytical applications.
(i) Different types of formation processes were studied including the role of membrane composition. We investigated the influence of mechanical strains and shear stress on spherical and tubular membranes. Fundamental studies on membrane fusion were performed and revealed new insights into membrane fusion.
(ii) New methods were developed to control lipid fusion of artificial membranes and to form hybrid systems that are constituted of artificial membranes and cell membranes. These methods overcome current challenges in the formation of more sophisticated artificial systems and allow controlled building of more complex compositions.
(iii) We successfully developed screening platforms that allow the fast assessment of molecular properties such as membrane permeation coefficients and interaction with membrane receptors. These platforms can replace tedious cell-based assays, are fast and very cost-efficient with respect to sample consumption and moreover, simple in their practical use.
The platforms were developed for membrane analysis and synthetic biology, but we could employ many of them in the contexts of single-cell analysis and nanotechnology. In addition to the formation of lipid tubules, we extended our studies to other materials and created metal-organic fibres and wires with diameters ranging from several hundred nanometers to a few micrometers. We could demonstrate in first studies that the microfluidic platforms are a valuable tool to manipulate such small structures and facilitate their use, e.g. in sensing applications. Moreover, many platforms can be straightforward used for both vesicle and cell analysis. In this respect, we utilized platforms for cell trapping and isolation to quantify intracellular biomolecules in single-cell lysates by use of fluorescent assays and immunoassay.
In summary, microfluidic platforms are an excellent tool to support the formation and investigations of lipid-membrane based compartments. In the field of membrane biology these analytical platforms opened the way to address and answer new questions; and to answer existing open questions in a new, unconventional way. Microfluidics is the key technology to pave new directions in the field of synthetic biology, and will be allow the construction of more sophisticated artificial cells and cell aggregates in future.
Within the nµLIPID project, microfluidic devices were developed to form spherical structures (vesicles) and tubular structures by various techniques, including hydrodynamic focusing and micro-extrusion. Furthermore, we found solutions to immobilize and analyze the lipid membrane structures by shock-freezing, implementing trapping features to capture one or more large or giant vesicles, using chemical surface patterns to tether small vesicles and implementing tips to immobilize tubular structures.
These new platforms were employed in several studies, aiming at (i) fundamental understanding of membrane properties and membrane fusion, (ii) applications toward the engineering of complex artificial cells and (iii) the exploitation of the methods for sensors and analytical applications.
(i) Different types of formation processes were studied including the role of membrane composition. We investigated the influence of mechanical strains and shear stress on spherical and tubular membranes. Fundamental studies on membrane fusion were performed and revealed new insights into membrane fusion.
(ii) New methods were developed to control lipid fusion of artificial membranes and to form hybrid systems that are constituted of artificial membranes and cell membranes. These methods overcome current challenges in the formation of more sophisticated artificial systems and allow controlled building of more complex compositions.
(iii) We successfully developed screening platforms that allow the fast assessment of molecular properties such as membrane permeation coefficients and interaction with membrane receptors. These platforms can replace tedious cell-based assays, are fast and very cost-efficient with respect to sample consumption and moreover, simple in their practical use.
The platforms were developed for membrane analysis and synthetic biology, but we could employ many of them in the contexts of single-cell analysis and nanotechnology. In addition to the formation of lipid tubules, we extended our studies to other materials and created metal-organic fibres and wires with diameters ranging from several hundred nanometers to a few micrometers. We could demonstrate in first studies that the microfluidic platforms are a valuable tool to manipulate such small structures and facilitate their use, e.g. in sensing applications. Moreover, many platforms can be straightforward used for both vesicle and cell analysis. In this respect, we utilized platforms for cell trapping and isolation to quantify intracellular biomolecules in single-cell lysates by use of fluorescent assays and immunoassay.
In summary, microfluidic platforms are an excellent tool to support the formation and investigations of lipid-membrane based compartments. In the field of membrane biology these analytical platforms opened the way to address and answer new questions; and to answer existing open questions in a new, unconventional way. Microfluidics is the key technology to pave new directions in the field of synthetic biology, and will be allow the construction of more sophisticated artificial cells and cell aggregates in future.