Tracking intracellular forces and mechanical property changes in mouse one-cell embryo development.

Cells comprise mechanically active matter that governs their functionality, but intracellular mechanics are difficult to study directly and are poorly understood. However, injected nanodevices open up opportunities to analyse intracellular mechanobiology. Here, we identify a programme of forces and changes to the cytoplasmic mechanical properties required for mouse embryo development from fertilization to the first cell division. Injected, fully internalized nanodevices responded to sperm decondensation and recondensation, and subsequent device behaviour suggested a model for pronuclear convergence based on a gradient of effective cytoplasmic stiffness. The nanodevices reported reduced cytoplasmic mechanical activity during chromosome alignment and indicated that cytoplasmic stiffening occurred during embryo elongation, followed by rapid cytoplasmic softening during cytokinesis (cell division). Forces greater than those inside muscle cells were detected within embryos. These results suggest that intracellular forces are part of a concerted programme that is necessary for development at the origin of a new embryonic life.

Multidimensional Anisotropic Architectures on Polymeric Microparticles.

Next generation life science technologies will require the integration of building blocks with tunable physical and chemical architectures at the microscale. A central issue is to govern the multidimensional anisotropic space that defines these microparticle attributes. However, this control is limited to one or few dimensions due to profound fabrication tradeoffs, a problem that is exacerbated by miniaturization. Here, a vast number of anisotropic dimensions are integrated combining SU-8 photolithography with (bio)chemical modifications via soft-lithography. Microparticles in a 15-D anisotropic space are demonstrated, covering branching, faceting, fiducial, topography, size, aspect ratio, stiffness, (bio)molecular and quantum dot printing, top/bottom surface coverage, and quasi-0D, 1D, 2D, and 3D surface patterning. The strategy permits controlled miniaturization on physical dimensions below 1 µm and molecular patterns below 1 µm2 . By combining building blocks, anisotropic microparticles detect pH changes, form the basis for a DNA-assay recognition platform, and obtain an extraordinary volumetric barcoding density up to 1093 codes µm-3 in a 3 × 12 × 0.5 µm3 volume.

Cytoplasm mechanics and cellular organization.

As cells organize spatially or divide, they translocate many micron-scale organelles in their cytoplasm. These include endomembrane vesicles, nuclei, microtubule asters, mitotic spindles, or chromosomes. Organelle motion is powered by cytoskeleton forces but is opposed by viscoelastic forces imparted by the surrounding crowded cytoplasm medium. These resistive forces associated to cytoplasm physcial properties remain generally underappreciated, yet reach significant values to slow down organelle motion or even limit their displacement by springing them back towards their original position. The cytoplasm may also be itself organized in time and space, being for example stiffer or more fluid at certain locations or during particular cell cycle phases. Thus, cytoplasm mechanics may be viewed as a labile module that contributes to organize cells. We here review emerging methods, mechanisms, and concepts to study cytoplasm mechanical properties and their function in organelle positioning, cellular organization and division.

Intracellular Mechanical Drugs Induce Cell-Cycle Altering and Cell Death.

Current advances in materials science have demonstrated that extracellular mechanical cues can define cell function and cell fate. However, a fundamental understanding of the manner in which intracellular mechanical cues affect cell mechanics remains elusive. How intracellular mechanical hindrance, reinforcement, and supports interfere with the cell cycle and promote cell death is described here. Reproducible devices with highly controlled size, shape, and with a broad range of stiffness are internalized in HeLa cells. Once inside, they induce characteristic cell-cycle deviations and promote cell death. Device shape and stiffness are the dominant determinants of mechanical impairment. Device structural support to the cell membrane and centering during mitosis maximize their effects, preventing spindle centering, and correct chromosome alignment. Nanodevices reveal that the spindle generates forces larger than 114 nN which overcomes intracellular confinement by relocating the device to a less damaging position. By using intracellular mechanical drugs, this work provides a foundation to defining the role of intracellular constraints on cell function and fate, with relevance to fundamental cell mechanics and nanomedicine.

Integrating magnetic capabilities to intracellular chips for cell trapping.

Current microtechnologies have shown plenty of room inside a living cell for silicon chips. Microchips as barcodes, biochemical sensors, mechanical sensors and even electrical devices have been internalized into living cells without interfering their cell viability. However, these technologies lack from the ability to trap and preconcentrate cells in a specific region, which are prerequisites for cell separation, purification and posterior studies with enhanced sensitivity. Magnetic manipulation of microobjects, which allows a non-contacting method, has become an attractive and promising technique at small scales. Here, we show intracellular Ni-based chips with magnetic capabilities to allow cell enrichment. As a proof of concept of the potential to integrate multiple functionalities on a single device of this technique, we combine coding and magnetic manipulation capabilities in a single device. Devices were found to be internalized by HeLa cells without interfering in their viability. We demonstrated the tagging of a subpopulation of cells and their subsequent magnetic trapping with internalized barcodes subjected to a force up to 2.57 pN (for magnet-cells distance of 4.9 mm). The work opens the venue for future intracellular chips that integrate multiple functionalities with the magnetic manipulation of cells.

Gestión de la calidad sanitaria en la Comunidad Autónoma de Extremadura / Healthcare quality management in the Autonomous Community of Extremadura

Desde el nuevo marco competencial después de las transferencias sanitarias en enero de 2002 a nuestra comunidad autónoma, se ha desarrollado en estos 2 años toda una base legislativa que nos permite estar en disposición de afrontar el reto de la calidad de nuestro sistema sanitario. Como figura novedosa se ha establecido la Gerencia Única de Área, que debe garantizar la continuidad de la atención sanitaria en todas sus dimensiones, y promover la aproximación de los servicios al ciudadano. En la Consejería de Sanidad, la Dirección General de Formación, Inspección y Calidad Sanitarias integra de manera legislativa y operativa las herramientas necesarias para el desarrollo e implementación de estrategias dirigidas a la calidad total, y que tendrán su máxima expresión en la elaboración del Plan Marco de Calidad del Servicio Sanitario Público Extremeño 2005-2008, abierto a la participación de agentes internos y externos, y que estará basado en los siguientes pilares o líneas maestras de la organización: calidad de atención sanitaria; calidad relacional con los usuarios y profesionales; autorización y acreditación de centros, servicios y establecimientos sanitarios; evaluación sanitaria; investigación y formación; sistemas de información, desarrollo profesional; gestión y financiación (AU)