Graphene oxide-Au nano particle coated quartz crystal microbalance biosensor for the real time analysis of carcinoembryonic antigen

A label-free quartz crystal microbalance (QCM) biosensor was developed for the selective and real-time estimation of carcinoembryonic antigen (CEA) through the present study. Graphene oxide-Au nanoparticles (GO-AuNPs) was in situ synthesised on the surface of the QCM electrode and the antibody of CEA (monoclonal anti-CEA from mouse) was covalently immobilized on this layer as the bioreceptor for CEA. Mercaptoacetic acid–EDC–NHS reaction mechanism was used for anti-CEA immobilization. The effect of oxygen plasma treatment of the QCM electrode surface before bioreceptor preparation on the performance of the biosensor was tested and was found promising. CEA solutions with various concentrations were analysed using the bioreceptors to estimate the sensitivity and detection limit of the biosensor. The biosensors selectively recognized and captured CEA biomolecules with a detection limit of 0.06 and 0.09 ng mL−1 of CEA for oxygen plasma-treated (E2) and untreated (E1) bioreceptors, respectively. The sensitivity was estimated at 102 and 79 Hz, respectively, for E2 and E1. Clinical serum samples were analysed and the results were found in good agreement with the ELISA analysis. Long term stability was also found to be excellent. Langmuir adsorption isotherm was also conducted using the experimental results

Rheological and Mechanical Characterization of Renewable Resource Based High Molecular Weight PLA Nanocomposites

The present study discusses structural aspects of nanocomposites and the ability of layered nanosilicates to alter the flow behaviour of poly(lactic acid) (PLA) melts. In addition, dynamic and static mechanical properties of PLA nanocomposites prepared from melt mixing method have been also discussed. A comparative study of nanocomposite properties has been conducted using two different nanoclays, natural montmorillonite modified with alkyl ammonium surfactant (OMMT), and commercially available organosilicate, Cloisite 30B, as reinforcements within the PLA matrix. Since OMMT has undergone better intercalation within the matrix, the corresponding nanocomposite showed superior mechanical and rheological characteristics than its C30B counterpart.</jats:p

Highly stable, love-mode surface acoustic wave biosensor using Au nanoparticle-MoS2-rGO nano-cluster doped polyimide nanocomposite for the selective detection of carcinoembryonic antigen

Herein, presents a novel method for the preparation of a Love mode SAW biosensor for the selective detection of carcinoembryonic antigen (CEA) using a transuding polymer nanocomposite thin film based bioreceptor. Graphene oxide (GO) was synthesized using modified Hummers' method and flower-like MoS2 nanoparticles were allowed to grow on the 2D layers GO. The rGO-MoS2 was further used as a host for the synthesis of Au nanoparticles (AuNP) and the final three-component nano-cluster was introduced to the previously synthesized polyamic acid diethyl ethanolamine salt precursor. The uniform mixture was coated on the delay line area of SAW device and conducted thermal imidization process to obtain polyimide nanocomposite. The thickness of the thin film was optimized based on the insertion loss and centre frequency response of the SAW device. Further, anti-CEA self-assembled monolayer (SAM) based bioreceptor was prepared on the polyimide nanocomposite thin film through thioglycolic acid – EDC/NHS immobilization mechanism. The bioreceptor was tested for immunoassay analysis with CEA solution with varying concentrations. The LOD of the biosensor was estimated at 0.084 ng/ml. The real-time applicability of the biosensor was validated using clinical serum sample analysis and the selectivity was evaluated through the affinity test towards other common tumour marking proteins. The biosensor also showed excellent stability, only 10% reduction activity was observed till 80th day of storage. The antigen-antibody adsorption parameters were also evaluated through Langmuir and Freundlich adsorption isotherms

Impact of thermal processing or solvent casting upon crystallization of PLA nanocellulose and/or nanoclay composites

Here, we present how processing (solvent casting or isothermal crystallization) impacts crystallinity of poly(lactic acid) (PLA) and its nanocomposites (PLA/1 wt % cellulose nanofibers (CNFs), PLA/1 wt % nanoclay (C30B) or PLA/1 wt % CNF/1 wt % C30B. Polarized optical microscopy demonstrated a heterogeneous nucleation process during isothermal crystallization leading to smaller homogeneously distributed spherulites. With solvent casting, no effect on morphology was observed with respect to the nanoparticles, but an increased spherulite size was observed at higher temperatures. This fact raises significant concerns regarding the suitability of solvent casting as a lab‐scale procedure to investigate materials. Additionally, combining the reinforcing agents, CNF, and C30B, did not increase nucleation rate, in contrast with the general tendency, where the incorporation of both particles led to improved properties (e.g., thermomechanical and barrier properties). However, a combination of C30B and CNF did lead to an overall increase in the rigid amorphous fraction and a reduced mobile amorphous fraction

Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour

[EN] Green composites made of polylactide (PLA) filled with almond shell flour (ASF) at a constant weight content of 25¿wt.-% were manufactured by injection molding. In order to increase the interfacial adhesion between the biopolymer and the lignocellulosic fillers, three different compatibilizers were tested, namely multi-functional epoxy-based styrene-acrylic oligomer (ESAO), aromatic carbodiimide (AC), and maleinized linseed oil (MLO). The effect of each compatibilizer on the thermal, mechanical, and thermomechanical properties and water uptake of the injection-molded PLA/ASF pieces was analyzed. The obtained results indicated that all the here-studied compatibilizers had a positive influence on both the thermal stability and the mechanical and thermomechanical performance of the green composite pieces but low impact on their water uptake profile. In addition, the morphological analysis performed at the fracture surfaces of the green composite pieces revealed that the filler¿matrix gap was substantially reduced. Among the tested compatibilizers, ESAO and MLO yielded the highest performance in terms of mechanical strength and ductility, respectively. In the case of MLO, it also offers the advantage of being a plant-derived additive so that its application in green composites positively contributes to the development of sustainable polymer technologies.This research was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) program number MAT2014-59242-C2-1-R and AGL2015-63855-C2-1-R and Generalitat Valenciana (GV) program number GV/2014/008. A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia (UPV) for his FPI grant. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports (MECD) for his FPU grant (FPU13/06011). L. Quiles-Carrillo also wants to thank GV for his FPI grant (ACT/2016/182) and the MECD for his FPU grant (FPU15/03812).Quiles-Carrillo, L.; Montanes, N.; Garcia-Garcia, D.; Carbonell-Verdu, A.; Balart, R.; Torres-Giner, S. (2018). Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour. Composites Part B Engineering. 147:76-85. https://doi.org/10.1016/j.compositesb.2018.04.017S768514

Poly(lactic acid) composites reinforced with leaf fibers from ornamental variety of hybrid pineapple (Potyra).

While there have been many studies of fibers extracted from pineapple leaves as reinforcement in polymer composites, to date, only commercial varieties have been examined. This work aims to investigate the fibers from the leaves of a hybrid pineapple called Potyra as a mechanical reinforcement in a poly(lactic acid) (PLA) matrix. The fibers were pre-treated in a NaOH solution (1 wt%) and were incorporated into the PLA by a torque rheometer mixer followed by twin-screw extrusion. Samples of each composition were injected. The molded composites showed increases of tensile strength from 58.8 to 69.6 MPa, of Young?s modulus from 1.9 to 3.5 GPa, and of impact resistance from 28 to 44 J/m, and showed an increase of 58C in the heat deflection temperature (Abstract Figure). The measured tensile strength and Young?s modulus values are lower than the theoretical values obtained by micromechanics theory due to the pull-out of the matrix fiber and due to the orientation of the fibers in the composites. It was concluded that the pineapple hybrid fibers have potential for use as mechanical reinforcement in green composites. POLYM. COMPOS., 00:000?000, 2017. VC 2017 Society of Plastics Engineer

Polyethylene/Polyhydroxyalkanoates-based Biocomposites and Bionanocomposites

The development of advanced polymer composite materials having superior mechanical properties has opened up new horizons in the field of science and engineering. Polyethylene (PE) is considered one of the most widely used thermoplastics in the world due to its excellent properties which have excellent chemical inertness, low coefficient of friction, toughness, near-zero moisture absorption, ease of processing and electrical properties. Polyhydroxyalkanoates (PHAs) are garnering increasing attention in the biodegradable polymer market because of their promising properties such as high biodegradability in different environments. This chapter covers polyethylene/polyhydroxyalkanoates-based biocomposites and bionanocomposites. It summarizes many of the recent research accomplishments in the area of PE/PHAs-based biocomposites and bionanocomposites such as state-of-the-art regarding different methods of their preparation. Also discussed are different characterization techniques and use of PE/PHAs-based biocomposites and bionanocomposites in biomedical, packaging, structural, military, coating, fire retardant, aerospace and optical applications, along with recycling and lifetime studies