Fluffy and Ordered Graphene Multilayer Films with Improved Electromagnetic Interference Shielding over X‑Band

Highly ordered nitrogen-doped graphene multilayer films with large interlayer void are successfully fabricated by thermal annealing of the compact stacking graphene oxide/copper phthalocyanine (GO/CuPc) multilayer films. Scanning electron microscopic (SEM), X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopic (XPS), and electrical conductivity measurements indicate that the breakaway of oxygen functional groups on/in the GO sheets at high temperature and the in situ pyrolysis of CuPc molecules in the interlayer of graphene sheets synergistically facilitate the restoration of GO in graphitization, the effective nitrogen doping by replacing carbon atoms in graphene frameworks, the retention of layer-by-layer stacking structure of graphene sheets in plane, and the formation of interlayer voids, leading to the enhancement in the electrical conductivity (3.64 × 10³ S/m). In addition, due to the formation of a Fabry–Pérot resonance cavity in the unique layer-by-layer stacking structure with larger interlayer voids, constructive interference of internal reflections aligned between parallel reflecting planes endows the fluffy graphene multilayer films with excellent electromagnetic interference (EMI) shielding effectiveness (exceeds 25 dB in all X-bands). The optimal shielding effectiveness is up to 55.2 dB with a smaller thickness of 0.47 mm, which makes it possible to become a practical EMI shielding material with a distinct competitive advantage

Difunctional Microelectrode Arrays for Single-Cell Electrical Stimulation and pH Detection

Due to its direct effect on biomolecules and cells, electrical stimulation (ES) is now widely used to regulate cell proliferation, differentiation, and neurostimulation and is even used in the clinic for pain relief, treatment of nerve damage, and muscle rehabilitation. Conventional ES is mostly studied on cell populations, but the heterogeneity of cancer cells results in the inability to access the response of individual cells to ES. Therefore, detecting the extracellular pH change (ΔpHe) after ES at the single-cell level is important for the application of ES in tumor therapy. In this study, cellular ΔpHe after periodic impulse electrostimulation (IES) was monitored in situ by using a polyaniline (PANI)-modified gold microelectrode array. The PANI sensor had excellent sensitivity (53.68 mV/pH) and linear correlation coefficient (R2 = 0.999) over the pH range of 5.55–7.41. The cells showed different degrees of ΔpHe after the IES with different intervals and stimulation potential. A shorter pulse interval and a higher stimulation potential could effectively enhance stimulation and increase cellular ΔpHe. At 0.5 V potential stimulation, the cellular ΔpHe increased with decreasing pulse interval. However, if the pulse interval was long enough, even at a higher potential of 0.7 V, there was no significant additional ΔpHe due to the insufficient stimulus strength. Based on the above conclusions, the prepared PANI microelectrode arrays (MEAs) were capable of stimulating and detecting single cells, which contributed to the deeper application of ES in tumor therapy

Scheme of the real-time resistance measurement for <i>V. parahaemolyticus</i>.

<p>Briefly, the lecithin-dependent hemolysin (LDH) gene of <i>V. parahaemolyticus</i> was amplified by LAMP at first. The subsequent two products, DNA and pyrophosphate, both negative ions, were combined with a positive dye (Crystal violet) and positive ions (Mg2+), leading to an increase in the reaction liquid resistance. This resistance was measured in real-time using a electrode, and <i>V. parahaemolyticus</i> concentration was quantitatively detected through a derivative analysis.</p

Sensitivity and regression analyses of the real-time resistance measurement.

<p>A. The real-time resistance curve of <i>V. parahaemolyticus</i> in a concentration gradient. B. The derivative analysis of the real-time resistance measurement of <i>V. parahaemolyticus</i>. C. The regression analysis of the real-time resistance measurement of <i>V. parahaemolyticus.</i> Three samples of the same bacterial concentration were measured twice and all values were recorded as mean(n = 6).</p

Specificity analysis of the real-time resistance measurement.

<p>A. The real-time resistance curve of <i>V. parahaemolyticus</i> and other interfering bacteria. B. End-point resistance of <i>V. parahaemolyticus</i> and other interfering bacteria after a 60-min LAMP assay. C. Derivative analysis of the real-time resistance measurement.</p

Dual-Mode Fluorescence and Magnetic Resonance Imaging Nanoprobe Based on Aromatic Amphiphilic Copolymer Encapsulated CdSe@CdS and Fe₃O₄

Nanoparticles exhibiting good biocompatibility and multifunctional optical, magnetic, and reactive properties are essential materials for the construction of next generation theranostics platforms. The core–shell structured CdSe@CdS is one of few semiconductor quantum dots (QD) that shows ideal photoluminescence for biological application including unity quantum yields, identical photoluminescence for ensembles and single dot, nonblinking, and antibleaching. However, overcoming toxicity concerns from Cd²⁺ is still a great challenge for promoting the practical medical application of the CdSe@CdS QD. Besides, the high quality luminescent and superparamagnetic nanoparticles at present are basically hydrophobic, which implies that the phase transfer of these functional nanoparticles into aqueous phase is the primary step to enable their biomedical application. Herein, we have developed a facile protocol to fabricate highly biocompatible nanoparticles showing both modulated luminescent and magnetic properties via a one-step self-assembling of amphiphilic block copolyarylene ether nitriles (amPEN), oleic acid stabilized CdSe@CdS QD, and Fe₃O₄ superparamagnetic nanoparticles (SP) in microemulsion system. Benefiting from the aromatic backbone structure of amPEN and its strong hydrophobic interaction with surface capping agent of QD/SP, the fabricated hybrid nanoprobe exhibits quite competitive colloids stability as well as fluorescent/magnetic properties, which ensures its application for in vitro fluorescence and magnetic resonance (MR) imaging of cancer cells

Design and synthesis of a fluorescent probe based on naphthalene anhydride and its detection of copper ions - Fig 7

<p>The fluorescence images of LO-2 cells incubated with probe L (3 μM) (A); probe L after addition of 5 equivalents of Cu²⁺ ions (C); and their corresponding bright field images (B and D).</p

Effects of SOX2 on Proliferation, Migration and Adhesion of Human Dental Pulp Stem Cells

<div><p>As a key factor for cell pluripotent and self-renewing phenotypes, SOX2 has attracted scientists’ attention gradually in recent years. However, its exact effects in dental pulp stem cells (DPSCs) are still unclear. In this study, we mainly investigated whether SOX2 could affect some biological functions of DPSCs. DPSCs were isolated from the dental pulp of human impacted third molar. SOX2 overexpressing DPSCs (DPSCs-SOX2) were established through retroviral infection. The effect of SOX2 on cell proliferation, migration and adhesion ability was evaluated with CCK-8, trans-well system and fibronectin-induced cell attachment experiment respectively. Whole genome expression of DPSCs-SOX2 was analyzed with RNA microarray. Furthermore, a rescue experiment was performed with SOX2-siRNA in DPSC-SOX2 to confirm the effect of SOX2 overexpression in DPSCs. We found that SOX2 overexpression could result in the enhancement of cell proliferation, migration, and adhesion in DPSCs obviously. RNA microarray analysis indicated that some key genes in the signal pathways associated with cell cycle, migration and adhesion were upregulated in different degree, and the results were further confirmed with qPCR and western-blot. Finally, DPSC-SOX2 transfected with SOX2-siRNA showed a decrease of cell proliferation, migration and adhesion ability, which further confirmed the biological effect of SOX2 in human DPSCs. This study indicated that SOX2 could improve the cell proliferation, migration and adhesion ability of DPSCs through regulating gene expression about cell cycle, migration and adhesion, and provided a novel strategy to develop seed cells with strong proliferation, migration and adhesion ability for tissue engineering.</p></div

UV-vis spectra of fluorescent probe L (10 μM) upon addition of Cu²⁺ ions in CH₃CN:HEPES (3:2, v/v, pH = 7.4) solution.

<p>Insert: UV-vis titration profile of the fluorescent probe L at 465 nm.</p

Effect of SOX2-siRNA on the biological ability of DPSC-SOX2.

<p>(A) Analysis of effect of SOX2-siRNA on SOX2 expression in different groups by qPCR (left) and FACS (right). (B) Effect of SOX2-siRNA on the cell proliferation, migration and adhesion ability of DPSCs-SOX2. (C) QPCR detection of the key genes about cell cycle, cell migration and cell adhesion in DPSCs-SOX2, DPSCs-control and DPSCs-siRNA. Similar results were obtained in three independent experiments. Results are expressed as mean ± SEM. A t-test was used to compare the various groups, and P<0.05 was considered statistically significant. *P<0.05 compared with the normal DPSCs-SOX2 and DPSCs-control group respectively.</p