Investigation of soft matter nanomechanics by atomic force microscopy and optical tweezers: a comprehensive review

Soft matter exhibits a multitude of intrinsic physico-chemical attributes. Their mechanical properties are crucial characteristics to define their performance. In this context, the rigidity of these systems under exerted load forces is covered by the field of biomechanics. Moreover, cellular transduction processes which are involved in health and disease conditions are significantly affected by exogenous biomechanical actions. In this framework, atomic force microscopy (AFM) and optical tweezers (OT) can play an important role to determine the biomechanical parameters of the investigated systems at the single-molecule level. This review aims to fully comprehend the interplay between mechanical forces and soft matter systems. In particular, we outline the capabilities of AFM and OT compared to other classical bulk techniques to determine nanomechanical parameters such as Young’s modulus. We also provide some recent examples of nanomechanical measurements performed using AFM and OT in hydrogels, biopolymers and cellular systems, among others. We expect the present manuscript will aid potential readers and stakeholders to fully understand the potential applications of AFM and OT to soft matter systems

Estudio previo para la estandarización del proceso constructivo en los nuevos asentamientos residenciales en la región del vilayato de Adrar (Argelia)

[ES] El siguiente Trabajo Fin de Grado (TFG) realiza un estudio de los diferentes factores y condicionantes para la estandarización del proceso constructivo en los nuevos asentamientos residenciales en la región de vilayato de Adrar, ciudad situada al sur de Argelia y con un clima desértico. Argelia es hoy en día un país con una muy buena situación económica debido a su riqueza en recursos naturales (petróleo, gas, mercurio…) pero que adolece de viviendas, y de las infraestructuras que el país necesita. Por ello el gobierno está realizando unos importantes programas de inversión destinados a fomentar la industria y la construcción. Por ello, en este TFG analizamos los diferentes factores sociales, climáticos, religiosos, de infraestructuras… que nos permitirán el diseño de una vivienda estandarizada, de construcción rápida y sistemática, eficiente y que, además, cumpla con todas las necesidades de los habitantes de la región. Argelia es un país mayoritariamente de religión musulmana, lo que supone unas formas de vida introspectivas características del Islam, lo que conlleva prestar una especial atención a los sistemas de oscurecimiento y a la apertura de huecos. Además se adaptara la vivienda a uno de los sistemas de construcción modular existentes hoy en día en el mercado y se diseña el entramado de calles y manzanas que compondrán el nuevo asentamiento residencial.[EN] This Bachelor’s Thesis realizes a study of the different factors and determining for the standardization of the constructive process in the new residential accessions in the region of vilayato of Adrar, city placed to the south of Algeria and with a desert climate. Algeria is nowadays a country with a very good economic situation due to his wealth in natural resources (oil, gas, mercury …) but that suffers from housings, and infrastructures that the country needs. For it the government this one realizing a few strong programs of investments destined to promote the industry and the construction. With this, in this TFG we analyze the different factors, social, climatic, religious, of infrastructures … that allow us the design of a standardized housing, which allows his rapid and systematic, efficient construction and besides the fact that it expires with all the needs of the habitants of the region. Algeria is a country for the most part of Moslem religion, which supposes a few introspective forms of life typical of the Islam, which will suppose a special attention in the systems of dimness and in the opening hollow. In addition one was adapting the housing to one of the existing systems of modular construction nowadays on the market and there was designed the studding of streets and apples that compose the new residential accession.[FR] Le Travail suivant Fin de Degré (TFG) réalise une étude de différents facteurs et condicionantes pour la standardisation du processus constructif dans les nouvelles installations résidentielles dans la région de vilayato d'Adrar, une ville située au sud de l'Algérie et avec un climat désertique. L'Algérie est de nos jours un pays avec une très bonne situation économique grâce à sa richesse dans les ressources naturelles (un pétrole, un gaz, un mercure …) mais qui souffre des demeures, et les infrastructures dont le pays a besoin. Par cela le gouvernement réalise quelques forts programmes d'investissements destinés à promouvoir l'industrie et la construction. Avec cela, dans ce TFG nous analysons différents facteurs, sociaux, climatiques, religieux, des infrastructures … qui nous permettent le dessin d'une demeure standardisée, qui permette sa construction rapide et systématique, efficiente et de plus qui s'acquitte de toutes les nécessités des habitants de la région. L'Algérie est un pays majoritairement d'une religion musulmane ce qui suppose quelques formes introspectives de vie caractéristiques de l'Islam ce qui supposera une attention spéciale dans les systèmes d'obscurcissement et dans l'ouverture de creux. De plus on adaptera la demeure à l'un des systèmes existants d'une construction modulaire de nos jours sur le marché et on dessinait le lattis de rues et de pommes qui composent la nouvelle installation résidentielle.Marcuello Perales, JC. (2014). Estudio previo para la estandarización del proceso constructivo en los nuevos asentamientos residenciales en la región del vilayato de Adrar (Argelia). http://hdl.handle.net/10251/49361.Archivo delegad

Estudio de la tecnología de módulos fotovoltaicos flotantes en superficies de agua

El trabajo consta de un estudio acerca de la instalación de paneles fotovoltaicos sobre superficies de agua. Se estudia la tecnologia, los beneficios y defectos sobre los sistemas convencionales, y se realiza un análisis distintivo entre su instalación en España y en Polonia. (El trabajo fue realizado como Erasmus en Polonia)

Recent advances in sensing the inter-biomolecular interactions at the nanoscale – A comprehensive review of AFM-based force spectroscopy

Biomolecular interactions underpin most processes inside the cell. Hence, a precise and quantitative understanding of molecular association and dissociation events is crucial, not only from a fundamental perspective, but also for the rational design of biomolecular platforms for state-of-the-art biomedical and industrial applications. In this context, atomic force microscopy (AFM) appears as an invaluable experimental technique, allowing the measurement of the mechanical strength of biomolecular complexes to provide a quantitative characterization of their interaction properties from a single molecule perspective. In the present review, the most recent methodological advances in this field are presented with special focus on bioconjugation, immobilization and AFM tip functionalization, dynamic force spectroscopy measurements, molecular recognition imaging and theoretical modeling. We expect this work to significantly aid in grasping the principles of AFM-based force spectroscopy (AFM-FS) technique and provide the necessary tools to acquaint the type of data that can be achieved from this type of experiments. Furthermore, a critical assessment is done with other nanotechnology techniques to better visualize the future prospects of AFM-FS

Influence of surface chemistry of fiber and lignocellulosic materials on adhesion properties with polybutylene succinate at nanoscale

The production of bio-based composites with enhanced characteristics constitutes a strategic action to minimize the use of fossil fuel resources. The mechanical performances of these materials are related to the specific properties of their components, as well as to the quality of the interface between the matrix and the fibers. In a previous research study, it was shown that the polarity of the matrix played a key role in the mechanisms of fiber breakage during processing, as well as on the final properties of the composite. However, some key questions remained unanswered, and new investigations were necessary to improve the knowledge of the interactions between a lignocellulosic material and a polar matrix. In this work, for the first time, atomic force microscopy based on force spectroscopy measurements was carried out using functionalized tips to characterize the intermolecular interactions at the single molecule level, taking place between poly(butylene succinate) and four different plant fibers. The efficiency of the tip functionalization was checked out by scanning electron microscopy and energy-dispersive X-ray spectroscopy, whereas the fibers chemistry was characterized by Fourier-transform infrared spectroscopy. Larger interactions at the nanoscale level were found between the matrix and hypolignified fibers compared to lignified ones, as in control experiments on single lignocellulosic polymer films. These results could significantly aid in the design of the most appropriate composite composition depending on its final use

Beyond a platform protein for the degradosome assembly: the apoptosis-inducing factor as an efficient nuclease involved in chromatinolysis

The Apoptosis-Inducing Factor (AIF) is a moonlighting flavoenzyme involved in the assembly of mitochondrial respiratory complexes in healthy cells, but also able to trigger DNA cleavage and parthanatos. Upon apoptotic-stimuli, AIF redistributes from the mitochondria to the nucleus, where upon association with other proteins such as endonuclease CypA and histone H2AX, it is proposed to organize a DNA–degradosome complex. In this work, we provide evidence for the molecular assembly of this complex as well as for the cooperative effects among its protein components to degrade genomic DNA into large fragments. We have also uncovered that AIF has nuclease activity that is stimulated in the presence of either Mg2+ or Ca2+. Such activity allows AIF by itself and in cooperation with CypA to efficiently degrade genomic DNA. Finally, we have identified TopIB and DEK motifs in AIF as responsible for its nuclease activity. These new findings point, for the first time, to AIF as a nuclease able to digest nuclear dsDNA in dying cells, improving our understanding of its role in promoting apoptosis and opening paths for the development of new therapeutic strategies

Hydrocolloids of egg white and gelatin as a platform for hydrogel-based tissue engineering

Innovative materials are needed to produce scaffolds for various tissue engineering and regenerative medicine (TERM) applications, including tissue models. Materials derived from natural sources that offer low production costs, easy availability, and high bioactivity are highly preferred. Chicken egg white (EW) is an overlooked protein-based material. Whilst its combination with the biopolymer gelatin has been investigated in the food technology industry, mixed hydrocolloids of EW and gelatin have not been reported in TERM. This paper investigates these hydrocolloids as a suitable platform for hydrogel-based tissue engineering, including 2D coating films, miniaturized 3D hydrogels in microfluidic devices, and 3D hydrogel scaffolds. Rheological assessment of the hydrocolloid solutions suggested that temperature and EW concentration can be used to fine-tune the viscosity of the ensuing gels. Fabricated thin 2D hydrocolloid films presented globular nano-topography and in vitro cell work showed that the mixed hydrocolloids had increased cell growth compared with EW films. Results showed that hydrocolloids of EW and gelatin can be used for creating a 3D hydrogel environment for cell studies inside microfluidic devices. Finally, 3D hydrogel scaffolds were fabricated by sequential temperature-dependent gelation followed by chemical cross-linking of the polymeric network of the hydrogel for added mechanical strength and stability. These 3D hydrogel scaffolds displayed pores, lamellae, globular nano-topography, tunable mechanical properties, high affinity for water, and cell proliferation and penetration properties. In conclusion, the large range of properties and characteristics of these materials provide a strong potential for a large variety of TERM applications, including cancer models, organoid growth, compatibility with bioprinting, or implantable devices

Long-Term Results of Single-Anastomosis Duodeno-ileal Bypass with Sleeve Gastrectomy (SADI-S)

Background Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) is a simplification of the duodenal switch (DS) in which the alimentary limb is eliminated, and the common channel is lengthened from 200 to 300 cm. Short-term results have demonstrated that SADI-S is safe and reproducible and that weight loss and comorbidities resolution are comparable to biliopancreatic diversion or DS. Objective To analyze the long-term outcomes of SADI-S. Methods From May 2007 to December 2015, 164 patients were consecutively submitted to a one-step SADI-S. The mean age was 47 years, and the mean body mass index (BMI) was 45.8 kg/m2. A total of 101 patients had type 2 diabetes, 91 arterial hypertension, 81 obstructive apnea, and 118 dyslipidemia. Limb length was 200 cm in 50 cases, 250 cm in 99, and 300 cm in 15. Results There was no mortality. One patient had a gastric leak, and 2 patients had an anastomotic leak. A total of 25% of the patients were lost to follow-up at 10 years. Excess weight loss and total weight loss were 87% and 38% at 5 years and 80% and 34% at 10 years. A total of 12 patients were submitted to revisional surgery for hypoproteinemia. Preoperatively 41 diabetics were under insulin treatment; at 5 years, 7 remained with insulin and 12 at 10 years. Mean glycemia was 104 mg/dL at 5 years and 118 mg/dL at 10 years. Mean HbA1c was 5.51% at 5 years and 5.86 at 10 years. Conclusion In the long term, SADI-S offers satisfactory weight loss and comorbidities resolution