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Cell-surface interactions studies to trigger stem cell differentiation
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Abstracts / Nanomedicine: Nanotechnology, Biology, and Medicine 3 (2007) 337–346
array of wave packets (photons and electrons) to image, detect and manipulate major dynamics of macromolecular assemblies as in the cellular context. The compilation and integration of methodology provide timeresolved observations on the reactivity of structures from near-atomic resolution to various molecular and cellular levels of descriptors. By permitting the visualization of macromolecules (e.g., guided by virus entry) in a native state, microscopy, biophotonics and tomography offer an effective tool to compile observations of single or population molecules with techniques by lightening the architectures of cellular compartments relevant to the dynamic assemblies of molecular machines. Teamwork research and creative multimodality of the complementary imaging methods are essential in revealing the common functional integrity that persists throughout the transient, nanomolecular interactions. doi:10.1016/j.nano.2007.10.049 S-VIII-5
Fig 1. A, Fluorescence microscopy pictures showing cells growing micropatterned fibronectin layers (pattern siza 2.5 micron). Fibronectin is stained red, focal contacts are in green. B, MSC cells growing on selective areas of PMMA substrates functionalised with fibronectin. Nuclei are stained in blue, while fibronectin is stained in red.
Mechanics of Nanoscale Biological Systems Meiners J-C, University of Michigan, Michigan, Illinois, USA Nanoscale systems that are larger than a molecule but smaller than a cell are important for a variety of biological functions and are of utmost promise for new classes of nanotherapeutics. These structures include large proteinnucleic acid complexes that are at the core of many cellular functions, or complex dendrimeric therapeutics. Biological systems on this scale have unique mechanical properties, which are determined in large part by the thermal fluctuations of their constituent parts. These entropic forces and force fluctuations play a large role in enabling their function. One of the most striking feature of these mechanical properties is that extremely low forces-typically of the order of hundred femtonewtons, which is small compared to other intracellular forces such as those exerted by molecular motors-can have a substantial effect on biological function. I will demonstrate this effect with experimental data that we obtained on a model system based on the lactose repressor in E. Coli, where we show that such small forces can indeed substantially inhibit the formation of the repressor-DNA loop, which in turn represses transcription. The role of the thermal fluctuations of these systems in the formation of DNA loops and their contribution to the free energy of forming them will be discussed in the context of a multiscale model for such large DNA-protein complexes. In conclusion, general lessons learnt for the mechanics of nanoscale biological systems and their impact on biomedical function will be presented and discussed. doi:10.1016/j.nano.2007.10.050
Fig 2. SEM and confocal images of MSC cells cultured on PMMA with A, 50 micron diameter donut structures and B, irregular structures: both sets of structures are 1 mm tall. Nuclei are stained in blue and actin filaments in red.
S-VIII-6 Cell-surface interactions studies to trigger stem cell differentiation Martínez E, RíosQMondragón I, PlaQRoca M, RodríguezQSegui S, Engel E, Mills CA, Sisquella X, Planell JA, Samitier J, Nanotechnology Platform, Barcelona Science Park (PCB), Josep Samitier, Barcelona, Bioengineering Institute of Catalonia (IBEC), Barcelona University, Barcelona, Spain In vivo, mammalian cells interact one another triggering diverse intracellular processes that control cell development. Similarly, the surrounding environment, constituted basically by the extracellular matrix (ECM) and soluble factors, causes cells to adapt to it reprogramming their intracellular machinery. Hence, artificial bio-functionalized substrates with nano and micropatterns might make cells develop according to the substrate design in a non-invasive approach; controlling specifically processes such as cell adhesion, survival, proliferation, migration and differentiation. The main objective of our work is to apply novel micro and nanofabrication techniques and surface modification strategies to generate well-defined topographical and biochemical cues for cell culture. To achieve this goal,
micro and nanostructured polymer substrates have been generated by nanoembossing and their biochemical surface properties modified by microcontact printing, nanoplotting and dip-pen nanolithography, transferring ECM proteins, which will be attached covalently to the surface. All these will be used to study their influence on cell adhesion, morphology, proliferation and differentiation. Results show that surface functionalisation with adhesion proteins such as fibronectin can be used to selectively attach and confine cells on specific surface locations. When micro and nanopatterned, fibronectin can also alter cell morphology, cytoskeletal organisation and stress level. On the other hand, surface micro and nanotopography proves special relevance in cell guiding and alignment processes but it also greatly affects cell morphology. The combination of both topographical and biochemical features gives very interesting results regarding cell differentiation. doi:10.1016/j.nano.2007.10.051
Abstracts / Nanomedicine: Nanotechnology, Biology, and Medicine 3 (2007) 337–346
array of wave packets (photons and electrons) to image, detect and manipulate major dynamics of macromolecular assemblies as in the cellular context. The compilation and integration of methodology provide timeresolved observations on the reactivity of structures from near-atomic resolution to various molecular and cellular levels of descriptors. By permitting the visualization of macromolecules (e.g., guided by virus entry) in a native state, microscopy, biophotonics and tomography offer an effective tool to compile observations of single or population molecules with techniques by lightening the architectures of cellular compartments relevant to the dynamic assemblies of molecular machines. Teamwork research and creative multimodality of the complementary imaging methods are essential in revealing the common functional integrity that persists throughout the transient, nanomolecular interactions. doi:10.1016/j.nano.2007.10.049 S-VIII-5
Fig 1. A, Fluorescence microscopy pictures showing cells growing micropatterned fibronectin layers (pattern siza 2.5 micron). Fibronectin is stained red, focal contacts are in green. B, MSC cells growing on selective areas of PMMA substrates functionalised with fibronectin. Nuclei are stained in blue, while fibronectin is stained in red.
Mechanics of Nanoscale Biological Systems Meiners J-C, University of Michigan, Michigan, Illinois, USA Nanoscale systems that are larger than a molecule but smaller than a cell are important for a variety of biological functions and are of utmost promise for new classes of nanotherapeutics. These structures include large proteinnucleic acid complexes that are at the core of many cellular functions, or complex dendrimeric therapeutics. Biological systems on this scale have unique mechanical properties, which are determined in large part by the thermal fluctuations of their constituent parts. These entropic forces and force fluctuations play a large role in enabling their function. One of the most striking feature of these mechanical properties is that extremely low forces-typically of the order of hundred femtonewtons, which is small compared to other intracellular forces such as those exerted by molecular motors-can have a substantial effect on biological function. I will demonstrate this effect with experimental data that we obtained on a model system based on the lactose repressor in E. Coli, where we show that such small forces can indeed substantially inhibit the formation of the repressor-DNA loop, which in turn represses transcription. The role of the thermal fluctuations of these systems in the formation of DNA loops and their contribution to the free energy of forming them will be discussed in the context of a multiscale model for such large DNA-protein complexes. In conclusion, general lessons learnt for the mechanics of nanoscale biological systems and their impact on biomedical function will be presented and discussed. doi:10.1016/j.nano.2007.10.050
Fig 2. SEM and confocal images of MSC cells cultured on PMMA with A, 50 micron diameter donut structures and B, irregular structures: both sets of structures are 1 mm tall. Nuclei are stained in blue and actin filaments in red.
S-VIII-6 Cell-surface interactions studies to trigger stem cell differentiation Martínez E, RíosQMondragón I, PlaQRoca M, RodríguezQSegui S, Engel E, Mills CA, Sisquella X, Planell JA, Samitier J, Nanotechnology Platform, Barcelona Science Park (PCB), Josep Samitier, Barcelona, Bioengineering Institute of Catalonia (IBEC), Barcelona University, Barcelona, Spain In vivo, mammalian cells interact one another triggering diverse intracellular processes that control cell development. Similarly, the surrounding environment, constituted basically by the extracellular matrix (ECM) and soluble factors, causes cells to adapt to it reprogramming their intracellular machinery. Hence, artificial bio-functionalized substrates with nano and micropatterns might make cells develop according to the substrate design in a non-invasive approach; controlling specifically processes such as cell adhesion, survival, proliferation, migration and differentiation. The main objective of our work is to apply novel micro and nanofabrication techniques and surface modification strategies to generate well-defined topographical and biochemical cues for cell culture. To achieve this goal,
micro and nanostructured polymer substrates have been generated by nanoembossing and their biochemical surface properties modified by microcontact printing, nanoplotting and dip-pen nanolithography, transferring ECM proteins, which will be attached covalently to the surface. All these will be used to study their influence on cell adhesion, morphology, proliferation and differentiation. Results show that surface functionalisation with adhesion proteins such as fibronectin can be used to selectively attach and confine cells on specific surface locations. When micro and nanopatterned, fibronectin can also alter cell morphology, cytoskeletal organisation and stress level. On the other hand, surface micro and nanotopography proves special relevance in cell guiding and alignment processes but it also greatly affects cell morphology. The combination of both topographical and biochemical features gives very interesting results regarding cell differentiation. doi:10.1016/j.nano.2007.10.051