Nitrogen-doped carbon hollow trunk-like structure as a portable electrochemical sensor for noradrenaline detection in neuronal cells

To date, the production and development of portable analytical devices for environmental and healthcare applications are rapidly growing. Herein, a portable electrochemical sensor for monitoring of noradrenaline (NA) secreted from living cells using mesoporous carbon-based materials was fabricated. The modification of the interdigitated electrode array (IDA) by nitrogen-doped mesoporous carbon spheres (N-doped MCS) and nitrogen-doped carbon hollow trunk-like structure (N-doped CHT) was used to fabricate the NA sensor. The N-doped CHT surface shows multiple holes distributed with micrometer-sized open holes (1–2 μm) and nanometer-sized thin walls (∼98 nm). The N-doped CHT surface heterogeneity of wrinkled and twisted hollow trunk structures improve the diffusion pathway and the NA molecules loading. The N-doped CHT/IDA showed a highly selective assay for monitoring of NA with high sensitivity (1770 μA/μM × cm2), a low detection limit (0.005 μM), and a wide linear range (0.01–0.3 μM). The N-doped CHT/IDA monitored the NA secreted from PC12 cells under various concentrations of simulation agents (KCl). The designed N-doped CHT/IDA provides a portable NA-sensor assay with facile signaling, good stability, high biocompatibility, in-vitro assay compatibility, and good reproducibility. Therefore, the designed sensor can be used as a portable sensor for NA detection in live cells and can be matched with portable smartphones after further developments

Three-Dimensional Circular Surface Curvature of a Spherule-Based Electrode for Selective Signaling and Dynamic Mobility of Norepinephrine in Living Cells

A highly sensitive protocol for signaling norepinephrine (NEP) in human fluids and neuronal cell line models should be established for clinical investigation of some neuronal diseases. A metal-free electrode catalyst was designed based on a sulfur-doped carbon spheroidal surface (S-CSN) and employed as a transducing element for selective signaling of NEP in biological samples. The designed electrode of S-CSN features a spherical construct and curvature surface to form a spheroidal nanolayer with an average layer size of <2 nm. S-CSN shows surface topography of a circular surface curvature with a rugged surface texture, ridge ends, and free open spaces between interlayers. The rich-space diversity surfaces offer highly active surface with facile molecular/electron diffusion, multi-diffusive centers, and high target loading along with in-/out-of-plane circular spheres of the S-CSN surface. The active doping of S atoms onto the carbon-based electrode creates an active transducing element with many active sites, strong binding to targeted molecules, facile diffusion of charges/molecules, long-term durability, and dense reactive exposure sites for signaling NEP at ultratrace levels. S-CSN could be a sensitive and selective nanosensor for signaling NEP and establishing a sensing protocol with high stability and reproducibility. The sensory protocol based on S-CSN exhibits high sensitivity and selectivity with a low detection limit of 0.001 μM and a wide linear range of 0.01–0.8 μM. The in vitro sensory protocol for NEP secreted from living cells (neuronal cell line model) under stimulated agents possesses high sensitivity, low cytotoxicity, and high biocompatibility. These results confirm the successful establishment of NEP sensor in human blood samples and neuronal cells for clinical investigation

Ultrasensitive in-vitro monitoring of monoamine neurotransmitters from dopaminergic cells

The design of biosensing assay of monoamine neurotransmitters (MANTs) such as epinephrine (Ep), norepinephrine (NE), and dopamine (DA), as well as the monitoring of these MANTs released from dopaminergic cells, are of particular interest. Electrochemical sensors based on the novel construction of nickel oxides (NiO) were fabricated and employed for electrochemical screening of MANTs. A novel NiO-lacy flower-like (NLF) geometrical structure with semi-spherical head surfaces connected with a trunk as an arm was achieved. The designed semi-spherical head associated with abundant and the well-dispersed tubular branches with needle-like open ends might lead to the creation of vascular vessels for facile diffusion and suitable accommodation of the released MANTs throughout active and wide-surface-area coverage, multi-diffusive pores, and caves with connective open macro-/meso-windows along the entire top-view nanoneedles of lacy flower head and trunk. These electrode surfaces possess high-index catalytic site facets associated with the formation of ridges/defects on {110}-top-cover surface dominants for strong binding, fast response, and signaling of MANTs. The NLF- modified electrode enabled high sensitivity for MANTs and a low limit of detection of 6 nM. Ultrasensitive in-vitro monitoring of DA released from dopaminergic cells (such as PC12) was realized. The NLF electrode was used to detect MANTs from its sources (PC12), and it could be used for clinical diagnosis

Polyaxial Locking Plate in Fractures of the Distal Radius

Introduction: Volar locking plate represents the gold standard method of treatment of unstable distal end radius fractures.&#x0D; Objectives: The Present study aimed to identify the functional and radiological outcomes of distal radius fractures treated by open reduction and internal fixation using polyaxial volar locking plate.&#x0D; Patients and Methods: We reviewed 25 unstable distal end radius fractures that were operated in Orthopedic Department in Tanta University Hospital with polyaxial volar locking plates June 2018 to June 2019. The mean age of the patients was 40.8±14.34 years (range 24 to 65) and the mean duration of follow-up was 8.61 ± 3.19 months (range 6 to 17). All of the patients underwent open reduction and internal fixation with polyaxial locking plate through over flexor carpi radialis approach. After three months, pain, tendon functions, ROM, hand grip as well as radial median and ulnar nerves functions were well assessed. X-rays were done to assure full fracture consolidation. At the end of follow up, clinical results were evaluated according to Quick DASH Score. Castaign radiological assessment score was used for radiological evaluation.&#x0D; Results: There was a significant improvement in the functional indices from twelve weeks to the final follow-up. According to Castaign radiological assessment score 10 patients (40%) had excellent results, 14 patients (56%) had good results and 1 patient (4%) had fair results, no patients had poor results at the final follow up. Compared the performance of the polyaxial locking plate to another monoaxial plate and reported an improved range of radial and ulnar deviation with the variable angle device but they use another plate system.&#x0D; Conclusions: The use of polyaxial locking plates in treating unstable distal end radius fractures is associated with excellent to good functional results with minimal complications.</jats:p

Hierarchical engineering of Mn2O3/carbon nanostructured electrodes for sensitive screening of acetylcholine in biological samples

Enzymeless electrochemical sensors have received considerable interest for the direct, sensitive, and selective monitoring of biomolecules in a complex biological environment. Here, we designed a nonenzymatic electrochemical sensor based on Mn2O3 nanolayers (NLs)/carbon (C) and Mn2O3 flower-like (FL)/C structure to detect acetylcholine (ACh) molecules in human fluids. The sensing properties and electrochemical activity varied based on the structural and chemical composition of Mn2O3-based materials. The Mn2O3NLs/C structure of two-dimensional NLs was arranged in parallel with a heterogeneous surface texture, stair-like step-by-step layer formation, and cracked layers that formed free spaces. Mn2O3FL/C was formed with an FL structure. The parallel and perpendicular buildup of sheets from the bottom to top and sheets spreading in all directions formed the FL structure of Mn2O3 with multi-structural defects and edges, and heterogeneous surface texture. This unique surface property of Mn2O3FL/C and composition facilitated target diffusion through the inner/outer surface and shortened the distance pathway. Moreover, the presence of carbon on the surface of Mn2O3 induced sensitivity and stability of Mn2O3, enhanced the electrochemical activity with high catalytic activity, hastened electron diffusion, and high loading of ACh molecules. The nonenzymatic ACh sensors of Mn2O3NLs/C and Mn2O3FL/C showed a good sensor design with low limits of detection (2 and 7 μM, respectively) and a linear range of 0.1–7 mM. The fabricated sensors provided high stability and selectivity, easy fabrication, multi-usage, and fast response motioning of ACh in a complex mixture of human fluids. The designed nonenzymatic sensors of Mn2O3NLs/C and Mn2O3FL/C signaled the ACh molecules with high stability and selectivity and can be used to investigate and follow up on several neuronal disorders