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Tailoring RGD local surface density at the nanoscale toward adult stem cell chondrogenic commitment

Nano Research 2017年第6期10卷 1959-1971页

作者： Anna Lagunas Iro Tsintzou yolanda vida.daniel collado Ezequiel Perez-Inestrosa Cristina Rodriguez Pereira Joana Magalhaes Jose A. Andrades Josep Samitier Networking Biomedical Research Center (CIBER) C/Monforte de Lemos 3-5 Pabellon 11 Planta 0 Madrid 28029 Spain Institute for Bioengineering of Catalonia (IBEC) Baldiri-Reixac 10-12 Barcelona 08028 Spain Instituto de Investigacion Biomedica de Malaga (IBIMA) Department of Organic Chemistry Universidad de Malaga (UMA) Malaga 29071 Spain Andalusian Centre for Nanomedicine and Biotechnology-BlONAND Parque Tecnoldgico de Andalucia Mdlaga 29590 Spain Unidad de Bioingenieria Tisulary Terapia Celular (GBTTC-CHUAC) Grupo de Reumatologia Instituto de Investigacion Biomedica de A Coru6a (INIBIC) Complexo Hospitalario Universitario de A Coruf~a (CHUAC) Sergas Universidade da Coruna (UDC) As Xubias 84 Coruna 15006 A Spain Cell Biology Genetics and Physiology Department University de Malaga (UMA) Campus Teatinos Malaga 29071 Spain Department of Engineering Electronics University of Barcelona (UB) Marti i Franques 1-11 Barcelona 08028 Spain

Arginine-glycine-aspartic acid （RGD） dendrimer-based nanopatterns on poly（L- lactic acid） were used as bioactive substrates to evaluate the impact of the RGD local surface density on the chondrogenic induction of adult human mesenchymal stem cells. During chondrogenic commitment, active extracellular matrix （ECM） remodeling takes place, playing an instructive role in the differentiation process. Although three-dimensional environments such as pellet or micromass cultures are commonly used for in vitro chondrogenic differentiation, these cultures are rather limited with respect to their ability to interrogate cells in celI-ECM interactions. In the present study, the nanopatterns of the tunable RGD surface density were obtained as a function of the initial dendrimer concentration. The local RGD surface density was quantified through probability contour plots for the minimum interparticle distance, constructed from the corresponding atomic force microscopy images, and correlated with the cell adhesion and differentiation response. The results revealed that the local RGD surface density at the nanoscale acts as a regulator of chondrogenic commitment, and that intermediate adhesiveness of cells to the substrates favors mesenchymal cell condensation and early chondrogenic differentiation.

关键词： dendrimer arginine-glycine-asparticacid (RGD) nanopattem human mesenchymalstem cells (hMSCs) chondrogenesis

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Large-scale dendrimer-based uneven nanopatterns for the study of local arginine-glycine-aspartic acid （RGD） density effects on cell adhesion

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Nano Research 2014年第3期7卷 399-409页

作者： Anna Lagunas Albert G. Castano Juan M. Artes yolanda vida.daniel collado Ezequiel Perez-lnestrosa Pau Gorostiza Silvia Claros Jose A. Andrades Josep Samitier Networking Biomedical Research Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN) Spain Institute for Bioengineering of Catalonia (IBEC) Baldiri-Reixac 15-2 1 Barcelona 08028 Spain Physical Chemistry Department University of Barcelona (UB) Martii Franques 1-11 Barcelona 08028 Spain Andalusian Centre for Nanomedicine and Biotechnology (BIONAND) Severo Ochoa 35 Mdlaga 29590 Spain Organic Chemistry Department University of Mdlaga (UMA) Campus Teatinos Malaga 29071 Spain Institucio Catalana de Recerca i Estudis Avanats (ICREA) Spain Cell Biology Genetics and Physiology Department University of Malaga (UMA) Campus Teatinos Malaga 29071 Spain Electronics Department University of Barcelona (UB) Martii Franques 1-11 Barcelona 08028 Spain t Present address: Electrical and Computer Engineering Department University of California Davis 95616 Davis CA USA

Cell adhesion processes are governed by the nanoscale arrangement of the extracellular matrix （ECM）, being more affected by local rather than global concentrations of cell adhesive ligands. In many cell-based studies, grafting of dendrimers on surfaces has shown the benefits of the local increase in concentration provided by the dendritic configuration, although the lack of any reported surface characterization has limited any direct correlation between dendrimer disposition and cell response. In order to establish a proper correlation, some control over dendrimer surface deposition is desirable. Here, dendrimer nanopatterning has been employed to address arginine-glycine-aspartic acid （RGD） density effects on cell adhesion. Nanopatterned surfaces were fully characterized by atomic force microscopy （AFM）, scanning tunneling microscopy （STM） and X-ray photoelectron spectroscopy （XPS）, showing that tunable distributions of cell adhesive ligands on the surface are obtained as a function of the initial dendrimer bulk concentration. Cell experiments showed a clear correlation with dendrimer surface layout： Substrates presenting regions of high local ligand density resulted in a higher percentage of adhered cells and a higher degree of maturation of focal adhesions （FAs）. Therefore, dendrimer nano- patterning is presented as a suitable and controlled approach to address the effect of local ligand density on cell response. Moreover, due to the easy modification of dendrimer peripheral groups, dendrimer nanopatterning can be further extended to other ECM ligands having density effects on cells.

关键词： dendrimer arginine-glycine-asparticacid atomic force microscopy scanning tunnelingmicroscopy cell adhesion focal adhesions

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Evaluation of Early Action Mechanisms in Peru Regarding Preparedness for El Nino

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International Journal of Disaster Risk Science 2019年第4期10卷 493-510页

作者： Julio Aguirre daniel De La Torre Ugarte Juan Bazo Paulo Quequezana Mauricio collado Department of Economics Universidad del Pacifico15072 LimaPeru Red Cross Red Crescent Climate Centre 2502 KC The HagueThe Netherlands Centro de Investigacion de Riesgo Resiliencia y Cambio Climatico(CIRCA)Universidad Tecnologica del Peru(UTP)15046 LimaPeru

In this article,we provide an impact evaluation of an intervention in Peru regarding preparedness for El Nino impacts in Picsi District of Chiclayo Province in Peru’s northwestern coastal Lambayeque *** effort involved the provision of special kits that reduce the potential damage to homes as a consequence of rainfall and floods associated with an El Nino-Southern Oscillation *** was collected in 2016 when this Forecast-based Financing early action was activated by an El Nino forecast,and after a coastal El Nino actually struck in *** dual database permits us to estimate the impact of the intervention on the damage level of homes by comparing those homes supported by the program with those homes not receiving pilot-program *** comparison is achieved by using propensity score matching techniques,which identify the most comparable homes to the ones that were supported by the *** main findings of the study suggest a positive impact of the program in terms of its effectiveness in mitigating the damage caused by the 2017 El Ni?*** results suggest a drop in the scale of house damage(less damage)by around 63%for a home that received the modular kit *** considering other specifications of the model,the decrease in the scale of house damage improves up to approximately 66%.

关键词： Early warning Early action El NinoSouthern Oscillation Forecast-based Financing Matching propensity score Perú Red Cross

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