Bi-allelic Loss-of-Function CACNA1B Mutations in Progressive Epilepsy-Dyskinesia.

The occurrence of non-epileptic hyperkinetic movements in the context of developmental epileptic encephalopathies is an increasingly recognized phenomenon. Identification of causative mutations provides an important insight into common pathogenic mechanisms that cause both seizures and abnormal motor control. We report bi-allelic loss-of-function CACNA1B variants in six children from three unrelated families whose affected members present with a complex and progressive neurological syndrome. All affected individuals presented with epileptic encephalopathy, severe neurodevelopmental delay (often with regression), and a hyperkinetic movement disorder. Additional neurological features included postnatal microcephaly and hypotonia. Five children died in childhood or adolescence (mean age of death: 9 years), mainly as a result of secondary respiratory complications. CACNA1B encodes the pore-forming subunit of the pre-synaptic neuronal voltage-gated calcium channel Cav2.2/N-type, crucial for SNARE-mediated neurotransmission, particularly in the early postnatal period. Bi-allelic loss-of-function variants in CACNA1B are predicted to cause disruption of Ca2+ influx, leading to impaired synaptic neurotransmission. The resultant effect on neuronal function is likely to be important in the development of involuntary movements and epilepsy. Overall, our findings provide further evidence for the key role of Cav2.2 in normal human neurodevelopment.MAK is funded by an NIHR Research Professorship and receives funding from the Wellcome Trust, Great Ormond Street Children's Hospital Charity, and Rosetrees Trust. E.M. received funding from the Rosetrees Trust (CD-A53) and Great Ormond Street Hospital Children's Charity. K.G. received funding from Temple Street Foundation. A.M. is funded by Great Ormond Street Hospital, the National Institute for Health Research (NIHR), and Biomedical Research Centre. F.L.R. and D.G. are funded by Cambridge Biomedical Research Centre. K.C. and A.S.J. are funded by NIHR Bioresource for Rare Diseases. The DDD Study presents independent research commissioned by the Health Innovation Challenge Fund (grant number HICF-1009-003), a parallel funding partnership between the Wellcome Trust and the Department of Health, and the Wellcome Trust Sanger Institute (grant number WT098051). We acknowledge support from the UK Department of Health via the NIHR comprehensive Biomedical Research Centre award to Guy's and St. Thomas' National Health Service (NHS) Foundation Trust in partnership with King's College London. This research was also supported by the NIHR Great Ormond Street Hospital Biomedical Research Centre. J.H.C. is in receipt of an NIHR Senior Investigator Award. The research team acknowledges the support of the NIHR through the Comprehensive Clinical Research Network. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, Department of Health, or Wellcome Trust. E.R.M. acknowledges support from NIHR Cambridge Biomedical Research Centre, an NIHR Senior Investigator Award, and the University of Cambridge has received salary support in respect of E.R.M. from the NHS in the East of England through the Clinical Academic Reserve. I.E.S. is supported by the National Health and Medical Research Council of Australia (Program Grant and Practitioner Fellowship)

Exploiting Reactor Geometry to Manipulate the Properties of Plasma Polymerized Acrylic Acid Films

A number of different reactor geometries can be used to deposit plasma polymer films containing specific functional groups and result in films with differing properties. Plasma polymerization was carried out in a low-pressure custom-built stainless steel T-shaped reactor using a radio frequency generator. The internal aluminium disk electrode was positioned in two different geometries: parallel and perpendicular to the samples at varying distances to demonstrate the effect of varying the electrode position and distance from the electrode on the properties of plasma polymerized acrylic acid (ppAAc) films. The surface chemistry and film thickness before and after aqueous immersion were analysed via X-ray photoelectron spectroscopy and spectroscopic ellipsometry, respectively. For a perpendicular electrode, the ppAAc film thicknesses and aqueous stability decreased while the COOH/R group concentrations increased as the distance from the electrode increased due to decreased fragmentation. For films deposited at similar distances from the electrode, those deposited with the parallel electrode were thicker, had lower COOH/R group concentrations and greater aqueous stability. These results demonstrate the necessity of having a well characterized plasma reactor to enable the deposition of films with specific properties and how reactor geometry can be exploited to tailor film properties

Electron Beam Lithography Nanopatterning of Plasma Polymers

Chemically patterned surfaces for biotechnology applications often require sub‐micron patterns to match specific sub‐cellular structures and control the presentation of proteins to single cell arrays. Plasma polymer coatings are used extensively in the biotechnology sector for biomaterials, cell culture and tissue engineering, but their patterning has not been investigated at the sub‐micron level. The resolution limit of plasma polymerized patterns with designed line widths of 900 to 20 nm is investigated via dual chemistry patterns of plasma polymerized acrylic acid and allylamine created with poly (methyl methacrylate) resist and electron beam lithography (EBL). Line widths are characterized via scanning electron microscopy and atomic force microscopy with surface chemistry analysis via time‐of‐flight secondary‐ion mass spectrometry (ToF‐SIMS). The smallest line width measured is 29 nm for a designed line width of 20 nm. High‐resolution nanoscale imaging is achieved using ToF‐SIMS, with lines down to ≈60 nm in width visible. This work demonstrates the successful fabrication and characterization of sub 100 nm dual plasma polymer patterns using EBL, establishing a clear route for large scale production of plasma polymerized nanopatterning

Characterising a Custom-Built Radio Frequency PECVD Reactor to Vary the Mechanical Properties of TMDSO Films

Plasma-polymerised tetramethyldisiloxane (TMDSO) films are frequently applied as coatings for their abrasion resistance and barrier properties. By manipulating the deposition parameters, the chemical structure and thus mechanical properties of the films can also be controlled. These mechanical properties make them attractive as energy adsorbing layers for a range of applications, including carbon fibre composites. In this study, a new radio frequency (RF) plasma-enhanced chemical vapour deposition (PECVD) plasma reactor was designed with the capability to coat fibres with an energy adsorbing film. A key characterisation step for the system was establishing how the properties of the TMDSO films could be modified and compared with those deposited using a well-characterized microwave (MW) PECVD reactor. Film thickness and chemistry were determined with ellipsometry and X-ray photoelectron spectroscopy, respectively. The mechanical properties were investigated by nanoindentation and atomic force microscopy with peak-force quantitative nanomechanical mapping. The RF PECVD films had a greater range of Young’s modulus and hardness values than the MW PECVD films, with values as high as 56.4 GPa and 7.5 GPa, respectively. These results demonstrated the varied properties of TMDSO films that could in turn be deposited onto carbon fibres using a custom-built RF PECVD reactor

Dual pH- and electro-responsive antibiotic-loaded polymeric platforms for effective bacterial detection and elimination

We describe a multi-tasking flexible system that is able to release a wide spectrum antibiotic (levofloxacin, LVX) under electrostimulation and act as a pH sensor for detecting bacterial infections. Combining anodic polymerization with plasma polymerization processes we engineered dual pH- and electro-responsive polymeric systems. Particularly, the manufactured devices consisted on a layer of poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PHEDOT) loaded with the LVX antibiotic and coated with a plasma polymer layer of poly(acrylic acid) (PAA). The PHEDOT acted as conductive and electro-responsive agent, while the PAA provided pH responsiveness, changing from a compact globular conformation in acid environments to an expanded open coil conformation in alkaline environments. The assembly between the PHEDOT layer and the PAA coating affected the electrochemical response of the former, becoming dependent on the pH detected by the latter. The conformational change experienced by the PAA layer as a function of the pH and the redox properties of PHEDOT were leveraged for the electrochemical detection of bacteria growth and for regulating the release of the LVX antibiotic, respectively. The effectiveness of the system as a stimulus-responsive antibiotic carrier and pH sensor was also investigated on strains of Escherichia coli and Streptococcus salivarius.Postprint (author's final draft

Improving the effects of plasma polymerization on carbon fiber using a surface modification pretreatment

Plasma and electrochemical treatments of carbon fibers for enhanced properties are often presented in opposition to each other. This work demonstrates the combination of these methodologies through the electrochemical attachment of nitroaryl moieties to the surface of the carbon fiber, prior to the deposition of plasma polymerized acrylic acid to the surface. Notably, the tensile strength of fibers having undergone both surface modification and plasma polymerization showed a significant increase (3.76 ± 0.08 GPa), relative to control fibers (3.31 ± 0.11 GPa), while plasma polymerization alone showed no change (3.39 ± 0.09 GPa). Additional benefits resulting from both treatments were observed when determining the fiber-to-matrix adhesion. Plasma polymerization of acrylic acid alone returned a 49% increase in interfacial shear strength (IFSS) compared to control (28.3 ± 1.2 MPa vs 18.9 ± 1.2 MPa, respectively). While the presence of nitrophenyl groups on the fiber prior to polymerization conferred an additional 24% improvement over plasma polymerization alone and a 73% improvement relative to control fibers (32.7 ± 0.5 MPa vs 18.9 ± 1.2 MPa, respectively). Finally, we present the first comparison of scanning electron microscopy (SEM) and helium ion microscopy (HIM) to visualize polymers on the carbon fiber surface. HIM shows a clear advantage over conventional SEM in visualizing non-conductive coatings on carbon fibers. Analysis of the samples by X-ray photoelectron spectroscopy (XPS) confirmed the desired chemistry had been imparted onto the surface, consistent with the plasma-polymerized acrylic acid coating and presence of nitro-aryl moieties

Robust Biocompatible Fibers from Silk Fibroin Coated MXene Sheets

Abstract Conductive fibers are needed for the development of flexible electronic and biomedical devices. MXene fibers show great promise for use in such applications because of their high conductivity. Current literature on MXene fiber development highlights the need for improving their mechanical properties and investigation of biocompatibility. Here the use of silk fibroin biopolymer as a MXene formulation additive for the production of MXene fibers is studied. It is found that the favorable silk fibroin–MXene interactions resulted in improved durability, withstanding up to 1 h of high frequency sonication in buffered solutions. Furthermore, fibers with ≈5 wt% silk fibroin displays interesting properties including high conductivity (≈3700 S cm−1), high volumetric capacitance (≈910 F cm−3), and non‐cytotoxicity toward THP‐1 monocytic cells. The results presented here provide an important insight into potential use of MXene fibers in flexible electronics and biomedical applications