Fab antibody fragment-functionalized liposomes for specific targeting of antigen-positive cells

Liposomes functionalized with monoclonal antibodies or their antigen-binding fragments have attracted much attention as specific drug delivery devices for treatment of various diseases including cancer. The conjugation of antibodies to liposomes is usually achieved by covalent coupling using cross-linkers in a reaction that might adversely affect the characteristics of the final product. Here we present an alternative strategy for liposome functionalization: we created a recombinant Fab antibody fragment genetically fused on its C-terminus to the hydrophobic peptide derived from pulmonary surfactant protein D, which became inserted into the liposomal bilayer during liposomal preparation and anchored the Fab onto the liposome surface. The Fab-conjugated liposomes specifically recognized antigen-positive cells and efficiently delivered their cargo, the Alexa Fluor 647 dye, into target cells in vitro and in vivo. In conclusion, our approach offers the potential for straightforward development of nanomedicines functionalized with an antibody of choice without the need of harmful cross-linkers.This work has received funding from the European Union's Seventh Framework Program (FP7/2007-2013; grant agreement NMP4-LA-2009-228827 NANOFOL) and Horizon 2020 Research and Innovation Program (grant agreement No 683356 - FOLSMART), further from the Portuguese Foundation for Science and Technology under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020.info:eu-repo/semantics/publishedVersio

Anticorrosive performance of commercial nanoceramic coatings on AISI 1010 steel

The aim of this work was to study the corrosion behavior of three commercial nanoceramic coatings in comparison to zinc phosphate coatings applied on mild steel (SAE 1010). The coatings were evaluated by scanning electron microscopy (SEM), profilometry and hydrophobicity. The electrochemical behavior was evaluated by dynamic polarization. The results showed that the samples coated with nanoceramics presented contact angles greater than 100°, achieving hydrophobic behavior. Evaluating the electrochemical behavior under dynamic polarization revealed that the nanoceramic coating containing chromium (CHT) exhibited a higher corrosion potential and lower current than the other nanoceramic coatings tested, although its performance in a dilute sodium chloride solution was below that of the zinc phosphate-based coating. Although the nanoceramic coatings exhibited poor electrochemical behavior compared to the zinc-based coatings, they had a higher corrosion resistance when associated with an organic coating

Effect of sterilization on the properties of a bioactive hybrid coating containing hydroxyapatite

The objective of this study was to evaluate the influence of sterilization on a hybrid coating obtained from a sol composed of alkoxysilane tetraethoxysilane (TEOS) and organoalkoxysilane methyltriethoxysilane (MTES) containing 10% (mass) of hydroxyapatite particles. The coating was obtained by dip coating, by applying two layers (protective/bioactive), which were cured at different temperatures (450°C and 60°C). The effects of sterilization on the superficial, electrochemical, bioactive, and mechanical properties of the coating were evaluated by performing different sterilization processes, namely, steam autoclave, hydrogen peroxide plasma, and ethylene oxide. Subsequently, the coating was characterized by using scanning electron microscopy (SEM/ FEG), and FTIR measurements were performed to characterize the chemical structure. The bioactivity and degradability of the coating were analyzed by mass variation after immersion in SBF and X-ray diffraction (XRD) analysis. )e electrochemical behavior was assessed by open circuit potential (OCP) and potentiodynamic polarization curves and the mechanical behavior by wear resistance. Results showed that all sterilization processes caused significant morphological changes in the hybrid coating. The autoclaved sample presented the highest structural chemical changes, and, consequently, the highest degradability, even though it had a superior bioactive behavior in relation to the other samples. In addition, the sterilization processes influenced the electrochemical behavior of the hybrid coating and altered the mechanical resistance to abrasion, thus presenting lower wear performance in relation to the nonsterilized sample

The use of body growth and kinship data from 16 generations for predicting Thoroughbred performance

Thoroughbred horses have been intensely raised for their athletic potential that is correlated with morphological parameters (i.e., body weight - BW, and withers height - WH). Optimum and consistent body development is aimed, but excessive growth rates may lead to the development of orthopedic diseases. This study aimed to generate growth rate curves and prediction models of Thoroughbred horses by analyzing BW and WH data collected monthly over 16 years of 378 animals (23.6 animals/year). The animals were checked from birth to 18 months (160 colts and 181 fillies) on a farm in the south of Brazil. A prediction performance ARIMA model was developed based on the BW and WH of the foals using a maximum and minimum range of 7320 observations. BW and WH were 54,1 kg and 102,5 cm at birth and 397,8 kg and 150,6 cm at 18 months of age, respectively. No differences were found between sex at any age. Moreover, we have established a nonlinear function for the growth curve and on average, foals were expected to get 7.4 times heavier and 1.5 times taller when animals were fully grown. Males showed greater BW uniformity than females, as females had a lower minimum BW than males. Significant statistical differences (P < 0,05%) were reported for BW and WH of foals between pairs of sires highlighting the kinship (paternal) effect on the animals’ development. Seventy-two pairs of stallions showed statistical relevance for BW and 91 for WH. The ARIMA model produced a linear trend of BW and WH for the forecasted years. In conclusion, we recommend that careful sire selection and adequate health (i.e., parasite control, vaccination), and nutrition strategies must be adopted to achieve superior body growth as estimated by the predicting model (positive scenario). The present protocol shall be used in studs worldwide to monitor horse development. The spreadsheet is available on request to the corresponding authors

Effect of tetraethoxy-silane (TEOS) amounts on the corrosion prevention properties of siloxane-poly(methyl methacrylate) hybrid coatings on galvanized steel substrates

Siloxane-poly(methyl methacrylate) (PMMA) organic-inorganic hybrid coatings were deposited on galvanized steel by the dip-coating sol-gel technique. Anticorrosion properties, as well as the morphological, surface and structural features were studied. Hybrid coatings were synthesized from tetraethoxy-silane (TEOS) and methyl methacrylate (MMA) as inorganic and organic phases, respectively, linked by 3-metacriloxypropyl-trimethoxysilane (TMSM) as a coupling agent. The MMA/TMSM ratio was kept constant, whereas the four TEOS/TMSM ratios were varied. The characterization of coatings was assessed using several techniques such as Scanning Electronic Microscopy (SEM), Contact Angle, Fourier Transform Infrared (FT-IR), Open Circuit Polarization (OCP), Atomic Force Microscopy (AFM) and Electrochemical Impedance Spectroscopy measurements (EIS). The EIS results, which were obtained for the hybrid coatings, were discussed based on an electrical equivalent circuit used to adjust the experimental data. The results showed that the increasing the TEOS content caused increase in coating thickness, increased in the surface roughness and increased in the surface hydrophobicity. The film with the highest TEOS content presented the best electrochemical performance, more effective in protecting against corrosion

Effect of tetraethoxy-silane (TEOS) amounts on the corrosion prevention properties of siloxane-poly(methyl methacrylate) hybrid coatings on galvanized steel substrates

Siloxane-poly(methyl methacrylate) (PMMA) organic-inorganic hybrid coatings were deposited on galvanized steel by the dip-coating sol-gel technique. Anticorrosion properties, as well as the morphological, surface and structural features were studied. Hybrid coatings were synthesized from tetraethoxy-silane (TEOS) and methyl methacrylate (MMA) as inorganic and organic phases, respectively, linked by 3-metacriloxypropyl-trimethoxysilane (TMSM) as a coupling agent. The MMA/TMSM ratio was kept constant, whereas the four TEOS/TMSM ratios were varied. The characterization of coatings was assessed using several techniques such as Scanning Electronic Microscopy (SEM), Contact Angle, Fourier Transform Infrared (FT-IR), Open Circuit Polarization (OCP), Atomic Force Microscopy (AFM) and Electrochemical Impedance Spectroscopy measurements (EIS). The EIS results, which were obtained for the hybrid coatings, were discussed based on an electrical equivalent circuit used to adjust the experimental data. The results showed that the increasing the TEOS content caused increase in coating thickness, increased in the surface roughness and increased in the surface hydrophobicity. The film with the highest TEOS content presented the best electrochemical performance, more effective in protecting against corrosion

Hoja de predicción: Número 7 - 2002 Enero 11

Hybrid films obtained by a sol-gel process are based on two important reactions: hydrolysis and condensation. The condensation reaction is influenced by the curing temperature, since it induces the development of the intrinsic properties of the gel. The aim of this work is to coat tinplate, a substrate widely used in the packaging industry, with monolayered and bilayered hybrid films modified with polyethylene glycol and obtained through dip-coating. The results showed that the bilayered hybrid film obtained at 60°C had a higher layer thickness, and the best performance in the electrochemical assays, as well as the most hydrophobic character, in relation to the other samples. For the monolayered systems, the 90°C-cured system showed a lower layer thickness; however, this system showed a more compact, uniform and less porous layer, and presented better electrochemical impedance results, in comparison with the 60°C-cured samples