Adaptively reconstructing network of soft elastomers to increase strand rigidity: towards free-standing electro-actuation strain over 100.

Soft biological tissues and muscles composed of semiflexible networks exhibit rapid strain-hardening behaviors to protect them from accidental rupture. In contrast, synthetic soft elastomers, usually featuring flexible networks, lack such behaviors, leading to a notorious issue when applying them to a promising artificial muscle technology (dielectric elastomer, DE), that is electromechanical instability (EMI) induced premature breakdown. We report that a facile thermomechanical training method can adaptively reconstruct the network of a soft triblock copolymer elastomer to transform its flexible network strands into semiflexible ones without extra chemical modifications and additives so that the electro-actuation performance is significantly enhanced by avoiding EMI. The free-standing actuators of trained elastomers exhibit a large stable electro-actuation strain and a high theoretical energy density (133%, 307 kJ m-3 at 158.1 V µm-1), and the capacity of actuating at low-temperature environments (-15 °C).

SNAP25 regulates the release of the Rabies virus in nerve cells via SNARE complex-mediated membrane fusion.

Recent studies have reported that host proteins regulate Rabies virus (RABV) infection via distinct mechanisms. The abnormal neural function caused by RABV infection is related to the abnormal synaptic signal transmission in which the RABV glycoprotein (G) is involved. In the present study, two recombinant Rabies viruses (rRABVs), namely rSAD-SAD-Flag-G and rSAD-CVS-Flag-G, were established and rescued based on rSAD and verified by indirect fluorescence assay (IFA), and western blotting (WB). To investigate how the G protein interacts with synaptosomal-associated protein 25 (SNAP25), primary neuronal cells (PNC) of embryonic mice were cultured and infected with rRABVs. Immunoprecipitation (IP) and LC-MS/MS analysis of glycoprotein-binding proteins, which were flag tagged, were carried out to determine the interaction of G protein and soluble N-ethylmaleimide-sensitive factor attachment protein receptor proteins (SNARE) complex in PNC. G protein and the SNARE member SNAP25 were co-expressed in HEK293 cells or primary neuronal cells to investigate their colocalization. Knockdown of SNAP25 with small interfering RNA (siRNA) was conducted on mNA cells, and rRABV replication was observed by IFA, qRT-PCR, and virus titration. The results indicated that rRABVs were successfully rescued and grew well in PNC. Flag-tag IP and confocal microscopy demonstrated that SNAP25 works together with G protein and colocalizes with G on the cytomembrane of HEK293 cells. The downregulation of SNAP25, using RNA interference, resulted in a significant decrease in the number of viral mRNAs, viral proteins, and virus particles. Furthermore, the regression of SNAP25 did not affect the initial infection of the virus but reduced the infectivity of progeny virions.

Thermoplastic Dielectric Elastomer of Triblock Copolymer with High Electromechanical Performance.

Dielectric elastomer (DE) actuators have been shown to have promising applications as soft electromechanical transducers in many emerging technologies. The DE actuators, which are capable of large actuation strain over a wide range of excitation frequencies, are highly desirable. Here, the first single-component DE of a triblock copolymer with attractive electromechanical performance is reported. Symmetric poly(styrene-b-butyl acrylate-b-styrene) (SBAS) is designed and synthesized. The SBAS actuator exhibits about 100% static actuation area strain and excellent dynamic performance, as evidenced by a wide half bandwidth of 300 Hz and a very high specific power of 1.2 W g-1 within the excitation frequency range of 300-800 Hz.