Formación de calculos renales de oxalato cálcico en mamíferos

Calcium oxalate (CaOx) is the main inorganic component of urolithiasis and is mainly present in the formation of kidney stones in humans. Additionally, oxalocalcic urolithiasis has become the most frequent type of kidney stones, for instance, oxalocalcic urolithiasis has substantially increased in dogs and cats over the last decades. In urolithiasis, urine is supersaturated with calcium and oxalate ions that promote nucleation, growth and aggregation of CaOx crystals. It is accepted that the presence of acidic macromolecules and inorganic compounds in urine is responsible not only for the molecular processes involved in lithiasis but also for the adhesion and endocytosis by renal epithelial cells. Patients with the tendency to form kidney stones may have an alteration in the structure and/or function of some inhibitors of crystallization. In the current review, we describe some general aspects of epidemiology and pathophysiology of oxalocalcic urolithiasis.  

Design and study of a photo-switchable polymeric system in the presence of ZnS nanoparticles under the influence of UV light irradiation

Recent progress in the field of photosensitive materials has prompted a need to develop efficient methods to synthesize materials with basic intermolecular architectural designs and novel properties. Accordingly, in this work we design and study a photoactive polymer as a photo-switchable polymeric system in the presence and absence of ZnS nanoparticles (average size < 10 nm) at 5 wt.%. The influence of UV light irradiation on its properties were also studied. The photoactive block copolymer was obtained from styrene (S) and methyl methacrylate (MMA) as monomers and 1-(2-hydroxyethyl)-3,3-dimethylindoline-6-nitrobenzopyran (SP) was grafted to the block copolymer backbone as a photochromic agent. Furthermore, the incorporation of ZnS (NPs) as photo-optical switch component into the system enhances the purple colored photo-emission, with the open form of the spiropyran derivative (merocyanine, MC). The ZnS stabilize the isomeric equilibrium in the MC interconversion of the photochromic agent. The photo-switchable properties of the PS-b-PMMA-SP in the presence of ZnS (NPs) were examined using UV-VIS spectroscopy, Photoluminescence (PL) spectroscopy, optical fluorescence and scanning electronic microscopy (SEM-EDX.). The observed changes in the absorbance, fluorescence and morphology of the system were associated to the reversible interconversion of the two states of the photochromic agent which regulates the radiative deactivation of the luminescent ZnS NPs component. After UV irradiation the photoactive polymer becomes purple in color. Therefore, these basic studies can lead to the development of innovative functional and nanostructured materials with photosensitive character as photosensitive molecular switches

Hybrid Biomaterials Based on Calcium Carbonate and Polyaniline Nanoparticles for Application in Photothermal Therapy

Inorganic materials contain remarkable properties for drug delivery, such as a large surface area and nanoporous structure. Among these materials, CaCO3 microparticles (CMPs) exhibit a high encapsulation efficiency and solubility in acidic media. The extracellular pH of tumor neoplastic tissue is significantly lower than the extracellular pH of normal tissue facilitating the release of drug-encapsulating CMPs in this area. Conducting polyaniline (PANI) absorbs light energy and transforms it into localized heat to produce cell death. This work aimed to generate hybrid CMPs loaded with PANI for photothermal therapy (PTT). The hybrid nanomaterial was synthesized with CaCO3 and carboxymethyl cellulose in a simple, reproducible manner. The CMP-PANI-Cys particles were developed for the first time and represent a novel type of hybrid biomaterial. Resultant nanoparticles were characterized utilizing scanning electron microscopy, dynamic light scattering, zeta potential, UV-vis, FTIR and Raman spectroscopy. In vitro HeLa cells in dark and irradiated conditions showed that CMP-PANI-Cys and PANI-Cys are nontoxic at the assayed concentrations. Hybrid biomaterials displayed high efficiency for potential PTT compared with PANI-Cys. In summary, hierarchical hybrid biomaterials composed of CMPs and PANI-Cys combined with near infrared irradiation represents a useful alternative in PTT.Fil: Neira Carrillo, Andrónico. Universidad de Chile; ChileFil: Yslas, Edith Inés. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Marini, Yazmin Amar. Universidad de Chile; ChileFil: Vásquez Quitral, Patricio. Universidad de Chile; ChileFil: Sánchez, Marianela. Universidad de Chile; ChileFil: Riveros, Ana. Universidad de Chile; ChileFil: Yáñez, Diego. Universidad de Chile; ChileFil: Cavallo, Pablo César. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Kogan, Marcelo Javier. Universidad de Chile; ChileFil: Acevedo, Diego Fernando. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Formación de calculos renales de oxalato cálcico en mamíferos

Calcium oxalate (CaOx) is the main inorganic component of urolithiasis and is mainly present in the formation of kidney stones in humans. Additionally, oxalocalcic urolithiasis has become the most frequent type of kidney stones, for instance, oxalocalcic urolithiasis has substantially increased in dogs and cats over the last decades. In urolithiasis, urine is supersaturated with calcium and oxalate ions that promote nucleation, growth and aggregation of CaOx crystals. It is accepted that the presence of acidic macromolecules and inorganic compounds in urine is responsible not only for the molecular processes involved in lithiasis but also for the adhesion and endocytosis by renal epithelial cells. Patients with the tendency to form kidney stones may have an alteration in the structure and/or function of some inhibitors of crystallization. In the current review, we describe some general aspects of epidemiology and pathophysiology of oxalocalcic urolithiasis.  

Electrocrystallization of Calcium Oxalate on Electrospun PCL Fibers Loaded with Phytic Acid as a Template

Crystallization occurs widely in living organisms where different organs could associate with the calcification process, such as the formation of calcium oxalate (CaOx) calculi in the urinary tract. However, the pathogenesis and the role of an inhibitor in the pathological processes involved in urolithiasis is poorly understood. Therefore, the use of phytic acid (PA) as an inhibitor for the organic fibrillar matrix is a novel approach to inhibit the formation of pathological CaOx crystals. Herein, electrospun polymer fiber meshes of polycaprolactone (PCL) with random (R) and aligned (A) fiber orientations containing PA were prepared by electrospinning, and their role as a 3D organic template in in vitro CaOx crystallization was investigated. CaOx crystals were generated on conductive tin indium oxide (ITO)-modified glass with R-PCL and A-PCL fibers in the presence of PA through an electrocrystallization (EC) procedure. This study provides a simple electrochemical approach to evaluate the role of PA as an inhibitor in the nucleation of pathological CaOx crystals. The resulting CaOx crystals were analyzed by chrono-potentiometry, optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). We found that PA and the fiber orientations are key factors in the nucleation and crystal growth of CaOx, achieving the stabilization of healthy CaOx crystal and the inhibition of the pathological crystal form

Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)

In this work, calcium oxalate (CaOx) precursors were stabilized by poly(acrylic acid) (PAA) as an additive under in vitro crystallization assays involving the formation of pre-nucleation clusters of CaOx via a non-classical crystallization (NCC) pathway. The in vitro crystallization of CaOx was carried out in the presence of 10, 50 and 100 mg/L PAA by using automatic calcium potentiometric titration experiments at a constant pH of 6.7 at 20 C. The results confirmed the successful stabilization of amorphous calcium oxalate II and III (ACOII and ACO III) nanoparticles formed after PNC in the presence of PAA and suggest the participation and stabilization of polymer-induced liquidprecursor (PILP) in the presence of PAA. We demonstrated that PAA stabilizes CaOx precursors with size in the range of 20–400 nm. PAA additive plays a key role in the in vitro crystallization of CaOx stabilizing multi-ion complexes in the pre-nucleation stage, thereby delaying the nucleation of ACO nanoparticles. Indeed, PAA additive favors the formation of more hydrated and soluble phase of ACO nanoparticles that are bound by electrostatic interactions to carboxylic acid groups of PAA during the post-nucleation stage. These findings may help to a better understanding of the pathological mineralization resulting in urolithiasis in mammals.Chilean Agency for Research and Development (ANID) - Fondecyt 1171520ACCDiS center, Fondap 15130011Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) 21181417Spanish Government European Commission RTI2018-099565-B-I00Junta de Andalucía RNM-179University of Granada (Unidad Científica de Excelencia) UCE-PP2016-0

Electrocrystallization of CaCO3 crystals obtained through Phosphorylated Chitin

A phosphorylated chitin (Chi-P) derivative was synthesized and its chemical structure was verified with Fourier-transform infrared spectroscopy (FTIR), elemental analysis, and thermogravimetric techniques (TGA). The influence of Chi-P used as a solid template through in vitro electrocrystallization (EC) supported on an indium zinc oxide (ITO) surface on the growth of calcium carbonate (CaCO3) was studied. CaCO3 crystals through EC essays were also compared with crystals obtained with the gas diffusion (GD) method. Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), chronopotentiometry, Raman, and powder X-ray diffractometry (XRD) characterized all resultant inorganic particles. Our findings revealed that the EC method selectively controlled the coexistence of truncate calcite and the metastable phase of vaterite. The crystals' morphology reflects the electrostatic interaction of phosphate moieties from Chi-P onto CaCO3 crystals through both EC and GD crystallization methods. We believe that the EC method represents a viable electrochemical approach for studying different inorganic minerals and could be useful as an in vitro classical crystallization method for the design of advanced inorganic materials with desirable shapes and properties.FONDECYT 1171520 ACCDiS - Chilean Council for Science and Technology (CONICYT) 15130011 University of Chile Chilean Council for Science and Technology (CONICYT), Unidad de Desarrollo Tecnologico (UDT), University of Concepcion Proyecto Basal PFB-2

Activation of early defense signals in seedlings of nicotiana benthamiana treated with chitin nanoparticles

Chitin is an excellent material for the synthesis of nanoparticles because it is an elicitor and can form nanostructured materials. The application of chitin nanoparticles (CNPs) in plants can activate early defense responses associated with chitin. In this study, CNPs were synthesized by water in oil (W/O) emulsion using an aqueous chitin solution. The CNPs were characterized and used to evaluate the activation of genes related to early responses to chitin and the production of reactive oxygen species (ROS) on seedlings ofNicotiana benthamiana. The CNPs had an average size of 280 nm in diameter, a polydispersity of 0.299, a surface charge of 26.9 mV, and their chemical composition was corroborated by the disappearance of microaggregated CNPs treated with chitinases observed under a microscope. Seedlings treated with CNPs for one hour revealed increments in the expression of genesSTZ,ATL2, andMAPK3,in contrast when they were treated with chitin oligomers, and no changes in geneCERK1was detected in both conditions. Finally, the synthesis of ROS mediated by CNPs was detected in seedlings, which was higher than those generated by the treatment of chitin oligomers. These results demonstrated the capability to generate CNPs by emulsion, which are capable of triggering responses related to early defense inN. benthamianamore efficiently than chitin oligomers.CONICYT-PCHA/Doctorado Nacional 2015-21151642 CONICYT-PAI/Concurso Nacional Insercion en el sector productivo 2018 T781811000

Capping gold nanoparticles with modified chitosan polymers for biomedical applications

With the purpose of obtaining stable and non-toxic nanocomposites with potential biomedical applications we coated gold nanoparticles (AuNP) with chitosan (CHI) and CHI grafted with poly(Nisopropilacrylamide) (PNIPAAm) and poly(N,N-dimethylacrylamide) (PDMAAm). We used a grafting reaction carried out by free radical initiation mechanism using potassium persulfate. We characterized the grafted CHI by FT-IR and thermogravimetry, grafting parameters were also calculated. Gold nanoparticles (AuNP) were obtained by reduction of the auric salt with citrate. Nanocomposites were obtained by mixing dropwise polymer solution into a AuNP solution under intense stirring, with variable AuNP:copolymer ratios. These were characterized using UV-Visible spectrophotometry and transmission electronic microscopy (TEM). The effects on cell viability of neuroblastoma SHSY-5Y cells were evaluated performing the MTT assay. CHI and the grafted CHI with PNIPA did not show effects on cell viability while PDMA p