Performance Comparison of a Duplex Implementation of the CDC EUA 2019-nCoV Assay with the Seegene Allplex-SARS-CoV-2 Assay for the Detection of SARS-CoV-2 in Nasopharyngeal Swab Samples.

RT-PCR tests have become the gold standard for detecting the SARS-CoV-2 virus in the context of the COVID-19 pandemic. Because of the extreme number of cases in periodic waves of infection, there is a severe financial and logistical strain on diagnostic laboratories. For this reason, alternative implementations and validations of academic protocols that employ the lowest cost and the most widely available equipment and reagents found in different regions are essential. In this study, we report an alternative implementation of the EUA 2019-nCoV CDC assay which uses a previously characterized duplex PCR reaction for the N1 and RNAse P target regions and an additional uniplex reaction for the N2 target region. Taking advantage of the Abbott m2000 Sample Preparation System and NEB Luna Universal Probe One-Step RT-qPCR kit, some of the most widely available and inexpensive nucleic acid extraction and amplification platforms, this modified test shows state-of-the-art analytical and clinical sensitivities and specificities when compared with the Seegene Allplex-SARS-CoV-2 assay. This implementation has the potential to be verified and implemented by diagnostic laboratories around the world to guarantee low-cost RT-PCR tests that can take advantage of widely available equipment and reagents.

Polymer Electrolytes as Energy-Harvesting Materials to Capture Electrical Energy from Dynamic Mechanical Deformations.

Ionic electroactive polymers (iEAPs) can generate electrical energy under bending deformations exhibiting great potential for fabricating energy harvesters from dynamic vibrating environments. According to a previous study, this flexoelectric energy-harvesting potential is explored in polymer electrolyte membrane (PEM) assemblies subjected to intermittent square wave bending modes. The above study reveals that the mechanoelectrical transduction is likely to be the consequence of ion polarization under a pressure gradient across the PEM thickness. To further evaluate the applicability of the PEM assemblies for harvesting energy from dynamic environments, oscillatory bending deformation is applied in the present study, whereby the complex flexoelectric coefficient corresponding to dynamic capacitance exhibits strong frequency dependence. At very high oscillatory bending frequencies, the ionic clouds inside the PEM assemblies cannot be fully polarized, and thus the corresponding energy output tends to become smaller. However, the PEM assemblies having higher ionic conductivities can enhance energy output at high frequencies. Of particular interest is that the incorporated ionic liquid (IL) is not only capable of effectively plasticizing the polymer network, but also expediting the ionic conductivity, thereby enhancing the electrical energy output, which in turn provides important design guidance for efficient polymer energy harvesters.

Flexo-Ionic Effect of Ionic Liquid Crystal Elastomers.

The first study of the flexo-ionic effect, i.e., mechanical deformation-induced electric signal, of the recently discovered ionic liquid crystal elastomers (iLCEs) is reported. The measured flexo-ionic coefficients were found to strongly depend on the director alignment of the iLCE films and can be over 200 µC/m. This value is orders of magnitude higher than the flexo-electric coefficient found in insulating liquid crystals and is comparable to the well-developed ionic polymers (iEAPs). The shortest response times, i.e., the largest bandwidth of the flexo-ionic responses, is achieved in planar alignment, when the director is uniformly parallel to the substrates. These results render high potential for iLCE-based devices for applications in sensors and wearable micropower generators.

A Novel Splice-Site Mutation in the ELN Gene Suggests an Alternative Mechanism for Vascular Elastinopathies.

The ELN gene encodes elastin, a fundamental protein of the extracellular matrix that confers elasticity to different tissues including blood vessels. The formation of elastin fibers is a complex process involving monomer coacervation and subsequent crosslinking. Mutations in exons 1-29 of the ELN gene have been linked to supravalvular aortic stenosis (SVAS) whereas mutations in exons 30-33 are associated with autosomal dominant cutis laxa (ADCL). This striking segregation has led to the hypothesis that distinct molecular mechanisms underlie both diseases. SVAS is believed to arise through haploinsufficiency while ADCL is hypothesized to be caused by a dominant negative effect. Here, we describe a patient with SVAS harboring a novel splice-site mutation in the last exon of ELN. The location of this mutation is not consistent with current knowledge of SVAS, since all mutations reported in the C-terminus have been found in ADCL patients, and a thorough evaluation did not reveal significant skin involvement in this case. RT-PCR analysis of skin tissue showed that C-terminal mutations in the region can lead to the production of aberrant transcripts through intron retention and activation of cryptic splice sites and suggest that disruption of the very last exon can lead to functional haploinsufficiency potentially related to SVAS.

Flexoelectricity in Flexoionic Polymer Electrolyte Membranes: Effect of Thiosiloxane Modification on Poly(ethylene glycol) Diacrylate and Ionic Liquid Electrolyte Composites.

The present article entails the generation of flexoelectricity during cantilever bending of a solid polymer electrolyte membrane (PEM), composed of poly(ethylene glycol) diacrylate (PEGDA) precursor and ionic liquid (hexylmethylimidazolium hexafluorophosphate). The effects of thiosiloxane modification of PEGDA precursor on glass transition, ionic conductivity, and flexoelectric performance have been explored as a function of PEM composition. The glass transition temperature (Tg) of the PEM declines with increasing thiosiloxane amount in the PEGDA co-network, while the ionic conductivity improves. The PEM/compliant carbonaceous electrodes assemblies were assembled to determine the flexoelectric coefficients by monitoring electrical voltage/current outputs for various PEM compositions under the intermittent square-wave and dynamic oscillatory sine-wave deformation modes. Of particular interest is that the room temperature flexoelectric coefficient exhibits strong frequency dependence in the vicinity of 0.01-10 Hz, suggesting that ion polarization and ion transport through the ion-dipole complexed networks can still be affected by the mobile side chain branches even in the elastic regime of the covalently bonded PEGDA network. The in-depth understanding of the effect of thiosiloxane side chain on flexoelectricity generation is anticipated to have impact on the development of mechanoelectrical energy conversion devices for energy harvesting applications from natural and dynamical environment.

Poly(ethylene glycol) Diacrylate Based Electro-Active Ionic Elastomer.

Preparation and low voltage induced bending (converse flexoelectricity) of crosslinked poly(ethylene glycol) diacrylate (PEGDA), modified with thiosiloxane (TS) and ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) (IL) are reported. In between 2µm PEDOT:PSS electrodes at 1 V, it provides durable (95% retention under 5000 cycles) and relatively fast (2 s switching time) actuation with the second largest strain observed so far in ionic electro-active polymers (iEAPs). In between 40 nm gold electrodes under 8 V DC voltage, the film can be completely curled up (270° bending angle) with 6% strain that, to the best of the knowledge, is unpreceded among iEAPs. These results render great potential for the TS/PEGDA/IL based electro-active actuators for soft robotic applications.

Mechanoelectrical Transduction of Polymer Electrolyte Membranes: Effect of Branched Networks.

The role of side-chain branching in flexoelectric properties of a flexible, ionic solid polymer electrolyte membrane (PEM) has been investigated subjected to mechanical bending. These PEMs were synthesized via photopolymerization of the bifunctional poly(ethylene glycol) diacrylate (PEGDA) network attached with monofunctional poly(ethylene glycol) methyl ether acrylate (PEGMEA) branches in their ternary mixtures with lithium bis(tri-fluoromethane sulfonyl) imide (LiTFSI) salt. Both the PEGDA polymer precursor and PEGDMA side branches are capable of ionizing the lithium salt, but the dissociated lithium cations can also form the complexation with ether oxygen of PEGDA. With increasing PEGMEA content, not only the glass transition temperature is lowered, but also the ionic conductivity increases with temperature, which may be attributed to plasticization by dangling PEGMEA side chains. The flexoelectric responses of PEMs were investigated under various intermittent and oscillatory cantilever bending modes as a function of PEM composition and frequency. Last but not the least, the mechanoelectrical energy conversion was evaluated for various PEGDA/PEGMEA compositions and discussed its potential applications in energy harvesting from natural resources such as wind and wave motions.

Electroresponsive Ionic Liquid Crystal Elastomers.

This paper describes the preparation, physical properties, and electric bending actuation of a new class of active materials-ionic liquid crystal elastomers (iLCEs). It is demonstrated that iLCEs can be actuated by low-frequency AC or DC voltages of less than 1 V. The bending strains of the unoptimized first iLCEs are already comparable to the well-developed ionic electroactive polymers. Additionally, iLCEs exhibit several novel and superior features, such as the alignment that increases the performance of actuation, the possibility of preprogrammed actuation patterns at the level of the cross-linking process, and dual (thermal and electric) actuations in hybrid samples. Since liquid crystal elastomers are also sensitive to magnetic fields and can also be light sensitive, iLCEs have far-reaching potentials toward multiresponsive actuations that may have so far unmatched properties in soft robotics, sensing, and biomedical applications.