Synthetic Micro/Nanomotors for Drug Delivery

Synthetic micro/nanomotors (MNMs) are human-made machines characterized by their capacity for undergoing self-propelled motion as a result of the consumption of chemical energy obtained from specific chemical or biochemical reactions, or as a response to an external actuation driven by a physical stimulus. This has fostered the exploitation of MNMs for facing different biomedical challenges, including drug delivery. In fact, MNMs are superior systems for an efficient delivery of drugs, offering several advantages in relation to conventional carriers. For instance, the self-propulsion ability of micro/nanomotors makes possible an easier transport of drugs to specific targets in comparison to the conventional distribution by passive carriers circulating within the blood, which enhances the drug bioavailability in tissues. Despite the promising avenues opened by the use of synthetic micro/nanomotors in drug delivery applications, the development of systems for in vivo uses requires further studies to ensure a suitable biocompatibility and biodegradability of the fabricated engines. This is essential for guaranteeing the safety of synthetic MNMs and patient convenience. This review provides an updated perspective to the potential applications of synthetic micro/nanomotors in drug delivery. Moreover, the most fundamental aspects related to the performance of synthetic MNMs and their biosafety are also discussed.This work was funded in part by MICINN under Grant PID2019-106557GB-C21 and by E.U. on the framework of the European Innovative Training Network—Marie Sklodowska-Curie Action Nano Paint (Grant Agreement 955612)

Soft Colloidal Particles at Fluid Interfaces

The assembly of soft colloidal particles at fluid interfaces is reviewed in the present paper, with emphasis on the particular case of microgels formed by cross-linked polymer networks. The dual polymer/colloid character as well as the stimulus responsiveness of microgel particles pose a challenge in their experimental characterization and theoretical description when adsorbed to fluid interfaces. This has led to a controversial and, in some cases, contradictory picture that cannot be rationalized by considering microgels as simple colloids. Therefore, it is necessary to take into consideration the microgel polymer/colloid duality for a physically reliable description of the behavior of the microgel-laden interface. In fact, different aspects related to the above-mentioned duality control the organization of microgels at the fluid interface, and the properties and responsiveness of the obtained microgel-laden interfaces. This works present a critical revision of different physicochemical aspects involving the behavior of individual microgels confined at fluid interfaces, as well as the collective behaviors emerging in dense microgel assemblies.This work was funded by MICINN under grant PID2019-106557GB-C21 and by the E.U. on the framework of the European Innovative Training Network Marie Sklodowska-Curie Action nanoPaInt (grant agreement 955612)

Polishing techniques for MEGARA pupil elements optics

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral-field and multi-object optical spectrograph for the 10.4m Gran Telescopio Canarias.. It will offer RFWHM ~6,000, 12,000 and 18,700 for the low- , mid- and high-resolution, respectively in the wavelength range 3650-9700Å. .The dispersive elements are volume phase holographic (VPH) gratings, sandwiched between two flat Fused Silica windows of high optical precision in large apertures. The design, based in VPHs in combination with Ohara PBM2Y prisms allows to keep the collimator and camera angle fixed. Seventy three optical elements are being built in Mexico at INAOE and CIO. For the low resolution modes, the VPHs windows specifications in irregularity is 1 fringe in 210mm x 170mm and 0.5 fringe in 190mm x 160mm. for a window thickness of 25 mm. For the medium and high resolution modes the irregularity specification is 2 fringes in 220mm x 180mm and 1 fringe in 205mm x 160mm, for a window thickness of 20mm. In this work we present a description of the polishing techniques developed at INAOE optical workshop to fabricate the 36 Fused Silica windows and 24 PBM2Y prisms that allows us to achieve such demanding specifications. We include the processes of mounting, cutting, blocking, polishing and testing

Integration and characterization of the cryogenic system of MEGARA

MEGARA (Multi-Espectrografo en GTC de Alta ResoluciOn para AstronomIa) is an optical Integral-Field Unit and Multi-Object Spectrograph designed for the GTC (Gran Telescopio de Canarias) 10.4m telescope in La Palma, it is expected that the spectrograph will be delivered to GTC towards the end of 2016. MEGARA includes an open cycle cryostat which harbors the scientific CCD of the instrument at an operating temperature of 153 K, this cryogenic system has been designed and integrated by the "Astronomical Instrumentation Lab for Millimeter Wavelengths" at the Instituto Nacional de Astrofsica, Optica y Electronica (INAOE) in Mexico. Early this year the cryostat has finished its fabrication and now it is on AIV phases, in this paper we report the cryostat CCD-head and dewar back integration, vacuum and cryogenic test results are also reported. The final integration of the cryostat with the other components of the instrument is taking place at LICA lab at the Universidad Complutense de Madrid

MEGARA spectrograph mechanics and opto-mechanics in the AIV phase

MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the GTC 10.4m telescope. The spectrograph is currently being integrated in the laboratory for a pre-shipping review in September 2016. This paper presents the current status and final performance of the spectrograph mechanics and opto-mechanics, composed of the mechanisms and the large optomechanical elements mounts

Design and testing of AR coatings for MEGARA optics

We present the antireflection coatings of the optical elements of MEGARA, the new integral field and multi-object spectrograph for the Gran Telescopio Canarias. We describe the methodology for optimizing the solutions. We also present the results of the final deposited coatings. The main optics require broadband coatings in the range from 370 nm to 980 nm for different materials with a mean R<1.3% at specific angles of incidence in each surface. For each material a specific arrangement of thicknesses of the same eight layers were produced and tested. For the spectrograph pupil elements four layer coatings were designed and produced R<0.3%. The design of main optics and pupil elements coatings have been shared between INAOE and CIO. The coating depositions have been performed at CIO in the Integrity 39 Denton Vacuum Deposition System. The main optics final coatings fulfill MEGARA requirements

Dymanics of interfacial systems

La presente Tesis Doctoral recoge el estudio experimental de la dinámica de sistemas poliméricos de diferente naturaleza en geometría restringida, es decir en condiciones de baja dimensionalidad como son las interfases. En concreto, se ha estudiado el comportamiento reológico de compuestos poliméricos en forma de monocapas de Langmuir y de sistemas mixtos constituidos por nanoparticulastensioactivo y proteína-tensioactivo, constituyendo ambos monocapas de Gibbs en interfases aire-agua. Con el propósito de realizar un estudio de la reología de interfases fluidas en una escala espacio-temporal lo más amplia posible se han desarrollado diversas metodologías específicas, las cuales extienden la reología interfacial desde la escala mesoscópica hasta la macroscópica. Tanto la descripción detallada de las metodologías experimentales específicas como los argumentos que avalan las hipótesis de partida, referentes al estudio de la dinámica interfacial de sistemas complejos en formas de monocapas solubles (Gibbs) e insolubles (Langmuir), se encuentran perfectamente formulados en la literatura especializada

Performance of MEGARA spectrograph optical elements

MEGARA is the new IFU and multiobject spectrograph for Gran Telescopio Canarias. The spectograph will offer spectral resolution R-fwhm similar to 6,000, 12,000 and 18,700. Except for the optical fibers and microlenses, the complete MEGARA optical system has been manufactured in Mexico. This includes a field lens, a 5-lenses collimator, a 7-lenses camera and a complete set of volume phase holographic gratings with 36 flat windows and 24 prisms. All these elements are very large and complex, with very efficient antireflection coatings. Here the optical performance of MEGARA collimator and camera lenses and the field lens is presented

Nonaffine deformation and tunable yielding of colloidal assemblies at the air-water interface.

Silica nanoparticles trapped at the air-water interface form a 2D solid state with amorphous order. We propose a theoretical model to describe how this solid-like state deforms under a shear strain ramp up to and beyond a yielding point which leads to plastic flow. The model accounts for all the particle-level and many-body physics of the system: nonaffine displacements, local connectivity and its evolution in terms of cage-breaking, and interparticle interactions mediated by the particle chemistry and colloidal forces. The model is able to reproduce experimental data with only two non-trivial fitting parameters: the relaxation time of the cage and the viscous relaxation time. The interparticle spring constant contains information about the strength of interparticle bonding which is tuned by the amount of surfactant that renders the particles hydrophobic and mutually attractive. This framework opens up the possibility of quantitatively tuning and rationally designing the mechanical response of colloidal assemblies at the air-water interface. Also, it provides a mechanistic explanation for the observed non-monotonic dependence of yield strain on surfactant concentration