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Large-scale purification of monoclonal antibodies using Protein A affinity chromatography continues to be one of the dominant processes in the production of biopharmaceuticals. In order to reduce the processing cost, ensure the purity of the product, and enable safe resin reuse, it is important to (a) estimate the quality of these resins, and (b) quantify the process-related impurities. This article presents the possibility of using a sensitive, rugged optical system as a process analysis tool for the assessment of resin fouling by quantification of the impurities like Protein A, host cell proteins (HCPs), and histones present in the elute. We have developed a conducting polymer-coated fiber optic sensor to detect these impurities, a flow cell to bypass the column elute directly toward the sensor, and associated electronics to make it a portable device for onsite applications. Protein A impurities (3 to 100 ng/mL) have been measured in pure buffer samples, while HCPs (100 to 350 ng/mL) and histone impurities (5 ng/mL to $1~\mu \text{g}$ /mL approximately) were detected in composite elute samples. In comparison to enzyme linked immunosorbent assay (ELISA)-based techniques, this low-cost, user-friendly sensing device demonstrates fast detection and high sensitivity for real-time monitoring of all process-related impurities. [ABSTRACT FROM AUTHOR]

One of the major challenges in wireless communication technologies is the antenna design. In this paper, a wideband flexible antenna made by covering a Kapton substrate with a flexible magnetodielectric polymer-based nanocomposite layer is proposed. This novel magnetodielectric polymer-based nanocomposite relies on carbon-coated cobalt (CCo) and is coated with a conjugated polymer, polyaniline (PANI). The nanocomposite (PANI/CCo) fabrication, whose morphology was studied via scanning electron microscopy, demonstrates a relative permeability, a dielectric permittivity, and a conductivity of 5.5, 4.3, and 7500 S/m, respectively. In this paper, two frequency bands are of interest [1.8–2.45 GHz (personal communication service and wireless local area network) and 5.15–5.825 GHz (wireless networks)]. The functioning of the antenna in free space and on body is numerically and experimentally investigated. The average specific absorption rate is also discussed. Thanks to its performance this magnetodielectric nanocomposite polymer (PANI/CCo) antenna has been found to be a good candidate for wearable applications where complex bending situations are encountered. [ABSTRACT FROM AUTHOR]

Magnetized (PANI-coated Fe3O4) epoxy resin was synthesized to produce $X$ -band microwave absorbing structures (MASs) with tuning thickness and fillers ratio. The structure and crystallinity of materials were checked by SEM and X-ray diffraction. It was found that the thickness, amount, and ratio of magnetized PANI-coated Fe3O4 affect the microwave absorption properties. Single layer MAS with 3 mm showed a reflection loss (RL) of −54 dB at 8.73 GHz and −41 dB at 9.52 GHz. However, a double-layer absorber based on 0.9 mm of the matching layer of PANI and the absorbing layer of magnetized (PANI-coated Fe3O4) epoxy resin composite with a thickness of 1.8 mm show a minimum RL value of −38 dB at 9.82 GHz and an absorption bandwidth of about 3.55 GHz with RL below −10 dB. In addition, by rising thicknesses the RL peak shift to lower frequency. A materials prepared with thin double-layer structure have a high absorption performances and broader bandwidth in $X$ -band. [ABSTRACT FROM PUBLISHER]

Electrically conducting polymers are advantageous hybrid materials for microelectronic biosensors due to their high bandgap sensitivity, possibilities for nanoscale surface area formation, and well-developed surface bioconjugation strategies. In this paper, we investigated whether those organic conductors can also be used to functionalize ion-sensitive floating-gate field-effect transistors (ISFGFETs) designed to measure biological binding events. We first subjected our device to 100% relative humidity (RH) and proved its viability in such a humid environment. Subsequently, we drop-casted viscoelastic polyaniline emeraldine salt on pristine transistors to construct organo-functionalized devices. The modified ISFGFETs were stable in aqueous environments and sensitive to cationic polyethyleneimine. The directions of the ISFGFET threshold voltage (VT) shifts agree with the corresponding open-circuit potential variations for the same reaction and pH-sensitive behaviors of Al2O3 sensing layer on the transistor. Such organo-modified ISFGFET sensor arrays are promising alternatives to traditional conductive polymer-based potentiometric biosensors due to their signal amplification, high throughput, and scalability advantages. [ABSTRACT FROM PUBLISHER]

The influence of addition of polyaniline functionalized multiwalled carbon nanotubes (PANI-MWNTs) on the positive temperature coefficient (PTC) characteristics of carbon black (CB) filled high-density polyethylene (HDPE) nanocomposite materials have been studied. Polymer nanocomposites were prepared by the combined solution and melt-mixing process. The experimental results showed that the PTC intensity and maximum resistivity of the hybrid nanocomposites were obviously influenced by the polyaniline functionalization of multiwalled carbon nanotubes (MWNTs). A noticeable PTC of resistivity was observed for PANI-MWNTs/CB/HDPE hybrid nanocomposites near the melting point of HDPE. This is due to the significant volume expansion near the melting point of the HDPE in presence of hybrid fillers and a sudden increase of the resistivity due to the disconnection of the conductive paths. The PTC effect of CB/HDPE composites can be effectively modified by the addition of PANI-MWNTs. [ABSTRACT FROM PUBLISHER]