The authors would like to thank the Vicerectorate of Research (VRI) of the Pontificia Universidad Catolica del Peru (PUCP) and the "Consejo Nacional de Ciencia Tecnologia e Innovacion Tecnologica (CONCYTEC)" for financial support.

The authors would like to thank the Direction of Research (DAI) of PUCP, the Science and Technology Council of Peru (CONCYTEC), the Spanish Research Council (CSIC) and the Generalitat Valenciana, Conselleria de Empresa, Universidad y Ciencia (project number ARVIV/2007/101) for financial support.

This work was supported by the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peru and the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT). The authors thank the staff at CAM-PUCP for help with the SEM images.

In this study, we analyzed the contribution of NH4I and glycerol on the ionic conductivity of carboxymethyl κ/ι-hybrid carrageenan-based solid bio-electrolytes. Electrochemical impedance spectroscopy was used to assess the electrochemical properties of the developed biopolymeric films and their interfaces over a wide range of frequencies (1& Hz–7& MHz). X-ray diffractograms demonstrated the increment of the amorphous fraction in the material as the NH4I content increases, suggesting an enhancement of ion transport processes and the successful incorporation of the salt into the host matrix.

This work was supported by the Vice-Rectorate for Research of the Pontificia Universidad Católica del Perú, the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT) and The National Innovation Program for Competitiveness and Productivity (INNOVATE-PERU) of the Peruvian Ministry of Production.

This research was funded by FONDECYT-CONCYTEC , grant number 063-2018-FONDECYT-BM .

The eggshell membrane (ESM) is a biopolymer network that may have potential applications in biomedicine, but it also may reveal important details regarding the behaviour of biopolymer networks. In this paper, we have studied the mechanical and morphological properties of the ESM in order to reveal important structure-property relationships. Light optical microscopy and atomic force microscopy were used to assess the morphology of the ESM. The mechanical properties of membranes and individual fibres were studied by means of tensile tests and nanoindentation tests, respectively. The mechanical behaviour of ESM networks in different environmental conditions showed a non-linear and a linear regime. As for elastomers and other biopolymer systems, the non-linear regime was modelled by the Mooney-Rivlin relation. The Young's modulus in the linear regime of the network was related to the Young's...

Bacterial cellulose (BC) and graphene are materials that have attracted the attention of researchers due to their outstanding properties. BC is a nanostructured 3D network of pure and highly crystalline cellulose nanofibres that can act as a host matrix for the incorporation of other nano-sized materials. Graphene features high mechanical properties, thermal and electric conductivity and specific surface area. In this paper we review the most recent studies regarding the development of novel BC-graphene nanocomposites that take advantage of the exceptional properties of BC and graphene. The most important applications of these novel BC-graphene nanocomposites include the development of novel electric conductive materials and energy storage devices, the preparation of aerogels and membranes with very high specific area as sorbent materials for the removal of oil and metal ions from water ...

The authors would like to thank the Vice-Rectorate for Research (VRI) of the Pontificia Universidad Catolica del Peru for financial support. They would like to thank The National Council of Science, Technology and Technological Innovation (CONCYTEC) for financial support.

A novel method to prepare BC nanocomposites reinforced with reduced graphene oxide (RGO) is reported. A simple hydrazine treatment is shown to in-situ reduce the graphene oxide (GO) incorporated to BC films while increasing their conductivity. Raman spectroscopy was used to confirm the presence of graphene and assess the effect of the hydrazine treatment on its structure. XRD tests revealed no changes on BC structure. We hypothesize that this treatment removes the hydroxyl and epoxy groups present on the reduced graphene and increases the content of nonoxygenated carbon. These changes account for the increase in conductivity of the BC-based films, which behaved as an insulating material before the hydrazine treatment and reach an average conductivity value of 12 S/m after such a treatment.

La carragenina se utilizó para preparar películas de carragenina reforzadas con nanobigotes de quitina. Se utilizó microscopia de fuerza atómica para caracterizar la morfología y rugosidad de las películas. La caracterización estructural se realizó mediante difracción de rayos X y espectroscopia infrarroja de transformada de Fourier. Las propiedades mecánicas se evaluaron mediante ensayos de tracción. Los nanocompuestos preparados se utilizaron como sustrato celular para explorar sus posibles aplicaciones biológicas. Se sembraron células HeLa en las muestras para evaluar su biocompatibilidad. Los resultados preliminares muestran buena proliferación celular pero baja adhesión celular, demostrando una posible aplicación de este nuevo material como sustrato para el cultivo de células tumorales.

Nostoc commune cyanobacteria grow in extreme conditions of desiccation and nutrient-poor soils. Their colonies form spherical gelatinous bodies are composed of a variety of polysaccharides that allow them to store water and nutrients. In this paper, we study this type of biological gel that shows characteristics of both chemical and physical gels. The structure of this gel was assessed by means of scanning electron microscopy, plate-plate rheometry, Fourier transform infrared spectroscopy and absorption/desorption tests. The storage modulus of this gel was found to be frequency independent, as is usual for chemical gels. The stress sweeps showed a reversible stress softening behaviour that was explained in terms of the physical nature of the interactions of this network. The high density of physical crosslinks probably allows this physical network to behave as a highly elastomeric chemic...

This work was supported by the Dirección General de Ciencia y Tecnología (DGCYT) [MAT2015-63955-R]; the Vice-Rectorate for Research of the Pontificia Universidad Católica del Perú and the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT).

The authors would like to thank the vice-rectorate for research of the Pontificia Universidad Católica del Perú and the Peruvian Council of Science and Technology (Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica–Fondo Nacional de Desarrollo Científico y Tecnológico) for financial support. Dr Vicente Lorenzo from the Polytechnical University of Madrid is acknowledged for providing technical support during the microhardness tests.

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Council of Science, Technology and Technological Innovation [CONCYTEC-FONDECYT]; and the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peru [VRI-PUCP].

This work was supported by the DGCYT [MAT2015-63955-R]; the Vice-Rectorate for Research of the Pontificia Universidad Católica del Perú and the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT).

The Vice-Rectorate for Research (VRI-PUCP) of the Pontificia Universidad Catolica del Peru and the National Council of Science, Technology and Technological Innovation (CONCYTEC-FONDECYT) are greatly acknowledged for financial support. The Institute of Polymer Science and Technology of the Spanish Council for Scientific Research (ICTP-CSIC, Madrid, Spain) is acknowledged for experimental assistance.

Se utilizaron exopolisacáridos (EPS) extraídos de cianobacterias de Nostoc commune para preparar sustratos celulares de baja adhesión para el crecimiento de células selectivas tumorales. Los sustratos fueron reforzados con bigotes de quitina y nanopartículas de almidón y caracterizados mediante espectroscopia infrarroja Fouriertransform, difracción de rayos X y pruebas de tracción. Se sembraron dos células independientes de anclaje, HeLa modificada por GFP y células THP-1 en las muestras para evaluar su interacción con los compuestos. Los resultados confirmaron la interacción de la superficie celular de los compuestos a base de EPS. Las propiedades mecánicas de estas películas se pueden adaptar controlando el tipo y la concentración del refuerzo, que se puede utilizar en el diseño de diferentes tipos de biomateriales.