Ternary nanocomposite comprising MnO2, GQDs, and PANI as a potential structure for humidity sensing applications.

Humidity sensing has been offering a noticeable contribution in different industrial, medical, and agricultural activities. Here, graphene quantum dots doped with polyaniline (PANI) and MnO2 were successfully prepared. The synthesized system is exposed to a set of structural, morphological, and optical investigations. The apparent crystallite size is less than 30 nm, reflecting the nanoscale of the structure, and thus validating the preparation route as evident on XRD pattern. SEM images show a fibrous structure where polyaniline dominates and covers most of the structure's surface. The evident bands of the FTIR spectrum are designated to the component used in synthesis confirming the chemical structure of the fabricated system. The humidity sensing study of the synthesized structure is carried out through a wide range of relative humidity (RH) levels range of 11-97%. The response and recovery times of the fabricated structure are found to be around 120 and 220s, respectively.

Recent Advanced in MXene Research toward Biosensor Development.

MXene is a rapidly emerging group of two-dimensional (2D) multifunctional nanomaterials, drawing huge attention from researchers of a broad scientific field. Reporting the synthesis of MXene was the following breakthrough in 2D materials following the discovery of graphene. MXene is considered the most recent developments of materials, including transition metal carbonitrides, nitrides, and carbides synthesized by etching or mechanical-based exfoliation of selective MAX phases. MXene has a plethora of prodigious properties such as unique interlayer spacing, high ion and electron transport, large surface area, excellent thermal and electrical conductivity, exceptional volumetric capacitance, thermal shock, and oxidation resistance, easily machinable and inherently hydrophilic, and biocompatibility. Owing to the abundance of tailorable surface function groups, these properties can be further enhanced by surface functionalization with covalent and non-covalent modifications via numerous surface functionalization methods. Therefore, MXene finds their way to a plethora of applications in numerous fields including catalysis, membrane separation, energy storage, sensing, and biomedicine. Here, the focus is on reviewing the structure, synthesis techniques, and functionalization methods of MXene. Furthermore, MXene-based detection platforms in different sensing applications are survived. Great attention is given to reviewing the applications of MXene in the detection of biomolecules, pathogenic bacteria and viruses, cancer biomarkers food contaminants and mycotoxins, and hazardous pollutants. Lastly, the future perspective of MXene-based biosensors as a next-generation diagnostics tool is discussed. Crucial visions are introduced for materials science and sensing communities to better route while investigating the potential of MXene for creating innovative detection mechanisms.

An electroceutical approach enhances myelination via upregulation of lipid biosynthesis in the dorsal root ganglion.

As the myelin sheath is crucial for neuronal saltatory conduction, loss of myelin in the peripheral nervous system (PNS) leads to demyelinating neuropathies causing muscular atrophy, numbness, foot deformities and paralysis. Unfortunately, few interventions are available for such neuropathies, because previous pharmaceuticals have shown severe side effects and failed in clinical trials. Therefore, exploring new strategies to enhance PNS myelination is critical to provide solution for such intractable diseases. This study aimed to investigate the effectiveness of electrical stimulation (ES) to enhance myelination in the mouse dorsal root ganglion (DRG)-anex vivomodel of the PNS. Mouse embryonic DRGs were extracted at E13 and seeded onto Matrigel-coated surfaces. After sufficient growth and differentiation, screening was carried out by applying ES in the 1-100 Hz range at the beginning of the myelination process. DRG myelination was evaluated via immunostaining at the intermediate (19 daysin vitro(DIV)) and mature (30 DIV) stages. Further biochemical analyses were carried out by utilizing ribonucleic acid sequencing, quantitative polymerase chain reaction and biochemical assays at both intermediate and mature myelination stages. Imaging of DRG myelin lipids was carried out via time-of-flight secondary ion mass spectrometry (ToF-SIMS). With screening ES conditions, optimal condition was identified at 20 Hz, which enhanced the percentage of myelinated neurons and average myelin length not only at intermediate (129% and 61%) but also at mature (72% and 17%) myelination stages. Further biochemical analyses elucidated that ES promoted lipid biosynthesis in the DRG. ToF-SIMS imaging showed higher abundance of the structural lipids, cholesterol and sphingomyelin, in the myelin membrane. Therefore, promotion of lipid biosynthesis and higher abundance of myelin lipids led to ES-mediated myelination enhancement. Given that myelin lipid deficiency is culpable for most demyelinating PNS neuropathies, the results might pave a new way to treat such diseases via electroceuticals.

Lysis of gram-positive and gram-negative bacteria by antibacterial porous polymeric monolith formed in microfluidic biochips for sample preparation.

Bacterial cell lysis is demonstrated using polymeric microfluidic biochips operating via a hybrid mechanical shearing/contact killing mechanism. These biochips are fabricated from a cross-linked poly(methyl methacrylate) (X-PMMA) substrate by well-controlled, high-throughput laser micromachining. The unreacted double bonds at the surface of X-PMMA provide covalent bonding for the formation of a porous polymeric monolith (PPM), thus contributing to the mechanical stability of the biochip and eliminating the need for surface treatment. The lysis efficiency of these biochips was tested for gram-positive (Enterococcus saccharolyticus and Bacillus subtilis) and gram-negative bacteria (Escherichia coli and Pseudomonas fluorescens) and confirmed by off-chip PCR without further purification. The influence of the flow rate when pumping the bacterial suspension through the PPM, and of the hydrophobic-hydrophilic balance on the cell lysis efficiency was investigated at a cell concentration of 10(5) CFU/mL. It was shown that the contribution of contact killing to cell lysis was more important than that of mechanical shearing in the PPM. The biochip showed better lysis efficiency than the off-chip chemical, mechanical, and thermal lysis techniques used in this work. The biochip also acts as a filter that isolates cell debris and allows PCR-amplifiable DNA to pass through. The system performs more efficient lysis for gram-negative than for gram-positive bacteria. The biochip does not require chemical/enzymatic reagents, power consumption, or complicated design and fabrication processes, which makes it an attractive on-chip lysis device that can be used in sample preparation for genetics and point-of-care diagnostics. The biochips were reused for 20 lysis cycles without any evidence of physical damage to the PPM, significant performance degradation, or DNA carryover when they were back-flushed between cycles. The biochips efficiently lysed both gram-positive and gram-negative bacteria in about 35 min per lysis and PPM regeneration cycle.