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“This is the Accepted Manuscript version of an article accepted for publication in Nanotechnology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6528/ab96e5”, Composites of nanostructured porous silicon and silver (nPSi-Ag) have attracted great attention due to the wide spectrum of applications in fields such as microelectronics, photonics, photocatalysis and bioengineering, Among the different methods for the fabrication of nanostructured composite materials, dip and spin-coating are simple, versatile, and cost-effective bottom-up technologies to provide functional coatings. In that sense, we aimed at fabricating nPSi-Ag composite layers. Using nPSi layers with pore diameter of 30 nm, two types of thin-film techniques were systematically compared: cyclic dip-coating (CDC) and cyclic spin-coating (CSC). CDC technique formed a mix of granular and flake-like structures of metallic Ag, and CSC method favored the synthesis of flake-like structures with Ag and Ag2O phases. Flakes obtained by CDC and CSC presented a width of 110 nm and 70 nm, respectively. Particles also showed a nanostructure surface with features around 25 nm. According to the results of EDX and RBS, integration of Ag into nPSi was better achieved using the CDC technique. SERS peaks related to chitosan adsorbed on Ag nanostructures were enhanced, especially in the nPSi-Ag composite layers fabricated by CSC compared to CDC, which was confirmed by FTDT simulations. These results show that CDC and CSC produce different nPSi-Ag composite layers for potential applications in bioengineering and photonics, This work was financially supported by Fondo Nacional de Desarrollo Científico y Tecnológico FONDECYT–Chile (grant number 11180395), FONDEQUIP–Chile (project 160152)

In the present work, the fabrication of hybrid porous silicon/green synthetized Ag microparticles was shown and the potential use as carriers for Ag nanoparticles and drug delivery was explored. Hybrid microparticles were fabricated by incorporating green synthetized Ag nanoparticles into porous silicon matrix. The main physicochemical characteristics of the hybrid systems were studied by several techniques including UV-vis spectroscopy, TEM, SEM, XRD and XPS. The toxicology of these hybrid systems was investigated by cell viability, MTT, and comet assays. In addition, the possibility to aggregate different drug to use as drug delivery system was demonstrated by using florfenicol as drug model, due to its importance in salmon industry. The experimental results showed the potential to use these hybrid systems as carries for drug delivery in salmon industry.

The applications of nanoparticles continue to expand into areas as diverse as medicine, bioremediation, cosmetics, pharmacology and various industries, including agri-food production. The widespread use of nanoparticles has generated concerns given the impact these nanoparticles – mostly metal-based such as CuO, Ag, Au, CeO2, TiO2, ZnO, Co, and Pt - could be having on plants. Some of the most studied variables are plant growth, development, production of biomass, and ultimately oxidative stress and photosynthesis. A systematic appraisal of information about the impact of nanoparticles on these processes is needed to enhance our understanding of the effects of metallic nanoparticles and oxides on the structure and function on the plant photosynthetic apparatus. Most nanoparticles studied, especially CuO and Ag, had a detrimental impact on the structure and function of the photosynthetic apparatus. Nanoparticles led to a decrease in concentration of photosynthetic pigments, especially chlorophyll, and disruption of grana and other malformations in chloroplasts. Regarding the functions of the photosynthetic apparatus, nanoparticles were associated with a decrease in the photosynthetic efficiency of photosystem II and decreased net photosynthesis. However, CeO2 and TiO2 nanoparticles may have a positive effect on photosynthetic efficiency, mainly due to an increase in electron flow between the photosystems II and I in the Hill reaction, as well as an increase in Rubisco activity in the Calvin and Benson cycle. Nevertheless, the underlying mechanisms are poorly understood. The future mechanistic work needs to be aimed at characterizing the enhancing effect of nanoparticles on the active generation of ATP and NADPH, carbon fixation and its incorporation into primary molecules such as photo-assimilates.

Over the last few years, the green synthesis of nanoparticles (NPs) using plant extracts has emerged as a promising methodology for the fabrication of metallic NPs (especially silver, copper, and gold NPs), as it involves an easy, fast, low-cost, and environmentally friendly bioprocess. However, many factors affect the sizes and morphologies of NPs biosynthesized by this method, including the nature of the plant extract, among others. Therefore, the green synthesis of metal NPs with defined stability, size, and morphology distribution remains under evaluation. In the present study, we propose aqueous extracts from the endemic-medicinal plant Budleja globosa (“Matico”) as an efficient bioproduct for the green synthesis of silver NPs (AgNPs). Experimental results indicate that room temperature, low concentrations of leaf extracts of B. globosa, and silver nitrate salt were sufficient to biosynthesize AgNPs with uniform size (16 nm) and shape distribution (spherical).

Green synthesis of nanoparticles (NPs) from plant extracts have emerged as a promising methodology for the fabrication of metallic NPs, as it involves an easy, fast, low-cost, and environmentally friendly bioprocess. In the present study, we propose aqueous extracts from the endemic-medicinal plant Peumus boldus (“Boldo”) as an easy, fast, low-cost, and efficient bioproduct for the green synthesis of silver NPs (AgNPs). Our results indicate that room temperature conditions, short reaction time (only 3 h), low concentrations (1%) of leaf extracts of P. boldus, and silver nitrate salts (2 mM) were sufficient to biosynthesize AgNPs in a uniform size (18 nm) and shape distribution (spherical). In addition, stable and pure AgNPs were obtained in this process at the same time.

Propolis is widely recognized for its various therapeutic properties. These are attributed to its rich composition in polyphenols, which exhibit multiple biological properties (e.g., antioxidant, anti-inflammatory, anti-angiogenic). Despite its multiple benefits, oral administration of polyphenols results in low bioavailability at the action site. An alternative to face this problem is the use of biomaterials at nano-micro scale due to its high versatility as carriers and delivery systems of various drugs and biomolecules. The aim of this work is to determine if nPSi-&beta, CD microparticles are a suitable material for the load and controlled release of caffeic acid (CA) and pinocembrin (Pin), two of the main components of a Chilean propolis with anti-atherogenic and anti-angiogenic activity. Polyphenols and nPSi-&beta, CD microparticles cytocompatibility studies were carried out with human umbilical vein endothelial cells (HUVECs). Results from physicochemical characterization demonstrated nPSi-&beta, CD microparticles successfully retained and controlled release CA and Pin. Furthermore, nPSi-&beta, CD microparticles presented cytocompatibility with HUVECs culture at concentrations of 0.25 mg/mL. These results suggest that nPSi-&beta, CD microparticles could safely be used as an alternate oral delivery system to improve controlled release and bioavailability of CA or Pin&mdash, and eventually other polyphenols&mdash, thus enhancing its therapeutic effect for the treatment of different diseases.

Oxidized hyaluronic acid cross-linked with adipic acid dihydrazide (oxi-HA/ADH) forms an injectable and biocompatible hydrogel suitable for treatment of musculoskeletal diseases and for drug delivery applications. In that sense, nanoporous silicon (nPSi) can be combined with biopolymers, such as oxi-HA/ADH hydrogel, to display new characteristics, which are not exhibited by the individual constituents alone. Under this context, in this work nPSi microparticles at concentrations from 0.1% to 1% m/v were embedded into oxi-HA/ADH hydrogel to improve its mechanical stability and enhance its control over drug release kinetics using Rose Bengal (RB) as a model drug because its cytotoxic effect in different cancer cell lines and tumors has been previously reported. Our results showed, for both compressive force and stress strength tests, that oxi-HA/ADH hydrogel with 1% nPSi microparticles doubled the values of control samples. Moreover, samples of oxi-HA/ADH with nPSi microparticles improved RB release kinetics control over pure oxi-HA/ADH hydrogel. Finally, the cell viability of nPSi microparticles embedded into oxi-HA/ADH hydrogel was confirmed using fibroblasts, This work was financially supported by FONDECYT–Chile (grant number 11180395), CONICYT PFCHA/DOCTORADO/2017-21172001 (Nelson Naveas) and CNPq 140924/2017-5 (Carla França). We thank Fig. 8. A) Cytotoxicity of nPSi microparticles. B) Cell viability of hydrogels. C.G. Franca ̧ et al. Microporous and Mesoporous Materials 310 (2021) 110634 11 Dr. Héctor Pesenti for providing the DRX facility (FONDEQUIP–Chile, project 160152), and Dr. Luis Sanhueza for optical measurements of UVVis spectroscopy

Ordered mesoporous silicas were synthesized via cooperative self-assembly by using rice husk ash as silica source and P123 as main pore structure-directing agent. The incorporation of CTAB and BRIJ C10 as co-surfactant templates by different methods was investigated. Silicas with different pore size and mono-, bi- and trimodal porosity were obtained as a function of the co-surfactant used and the hydrolysis step performed. Low-angle XRD and TEM results confirmed the well-ordered pore structure of the synthesized silicas.

The relative easiness of fabrication of porous silicon, along with the possibility of precisely controlling its many unique properties, has made it a promising material for different applications in a wide variety of fields. In particular, this material is being actively studied for biological and medical applications. Within this context, in this chapter we review the key properties of porous silicon and the most significant applications of porous silicon in the fields of biosensing, bioimaging, drug delivery, and tissue engineering. The different processes commonly used to tailor the behavior of porous silicon for specific applications are also described in detail.

ZnO is probably one of the most studied oxides since ZnO nanostructures are a very rich family of nanomaterials with a broad variety of technological applications. Although several chemical techniques offer the possibility to obtain such ZnO nanostructures, here we show that the controlled modification of the zinc surface by low-energy O bombardment leads to the formation of core-shell Zn/ZnO nano-pyramidal arrays that suppress the reflection of light decreasing the reflectivity below 6% in the wavelength range of 300-900 nm. This controlled and scalable protocol opens the door to a broad range of possibilities for the use of ion bombardment to produce surface modifications for technological applications in the field of photoelectric devices and solar cells., The financial support by the Ministerio de Economía y Competitividad (MINECO) of Spain through the CONSOLIDER-Ingenio 2010 (CSD2008-00023) and MAT2015-69035-REDC programs is gratefully acknowledged.

8 págs.; 8 figs., The fabrication of selectively functionalized micropatterns based on nanostructured porous silicon (nanoPS) by phase mask ultraviolet laser interference is presented here. This single-step process constitutes a flexible method for the fabrication of surface patterns with tailored properties. These surface patterns consist of alternate regions of almost untransformed nanoPS and areas where nanoPS is transformed into Si nanoparticles (Si NPs) as a result of the laser irradiation process. The size of the transformed areas as well as the diameter of the Si NPs can be straightforwardly tailored by controlling the main fabrications parameters including the porosity of the nanoPS layers, the laser interference period areas, and laser fluence. The surface patterns have been found to be appropriate candidates for the development of selectively-functionalized surfaces for biological applications mainly due to the biocompatibility of the untransformed nanoPS regions. © 2016 IOP Publishing Ltd, The authors gratefully acknowledge funding from Ministerio de Economía y Competitividad (Spain) under research projects MAT2013-46572-C2-1-R and MAT2014-54826-C2-1-R. R P acknowledges the grant JCI-2012_13034 from the Juan de la Cierva program.