Multi-walled carbon nanotubes-metal-organic framework nanocomposite based sensor for the monitoring of multiple monoamine neurotransmitters in living cells.

The levels of monoamine neurotransmitters (MNTs) including dopamine (DA), adrenaline (Adr), norepinephrine (NE) and 5-hydroxytryptamine (5-HT) in cells are useful indicators to explore the pathogenesis of MNTs-related diseases such as Alzheimer's disease, Parkinson's disease and depression. Herein, we constructed a novel electrochemical sensing platform based on multi-walled carbon nanotubes (MWCNTs)-amine functionalized Zr (IV) metal-organic framework (UIO-66-NH2) nanocomposite for the detection of multiple MNTs including DA, Adr, NE and 5-HT. The synergistic effect between MWCNTs and UIO-66-NH2 endowed the nanocomposite with high specific surface area, low interface impedance and superior electrocatalytic activity, which effectively enhance the electrochemical performance of the sensor. The MWCNTs-UIO-66-NH2 nanocomposite-based sensor exhibited satisfied sensitivity for the quantitative measurement of DA, Adr, NE and 5-HT, as well as low detection limit. The outstanding biocompatibility of the constructed sensor permitted it to be successfully implemented for the real-time monitoring of DA released by PC12 and C6 cells, providing a promising strategy for clinical diagnosis of MNTs-related disorders and diseases.

Flexible and multi-functional three-dimensional scaffold based on enokitake-like Au nanowires for real-time monitoring of endothelial mechanotransduction.

Endothelial cells are sensitive to mechanical force and can convert it into biochemical signals to trigger mechano-chemo-transduction. Although conventional techniques have been used to investigate the subsequent modifications of cellular expression after mechanical stimulation, the in situ and real-time acquiring the transient biochemical information during mechanotransduction process remains an enormous challenge. In this work, we develop a flexible and multi-functional three-dimensional conductive scaffold that integrates cell growth, mechanical stimulation, and electrochemical sensing by in situ growth of enokitake-like Au nanowires on a three-dimensional porous polydimethylsiloxane substrate. The conductive scaffold possesses stable and desirable electrochemical sensing performance toward nitric oxide under mechanical deformation. The prepared e-AuNWs/CC/PDMS scaffold exhibits a good electrocatalytic ability to NO with a linear range from 2.5 nM to 13.95 µM and a detection limit of 8 nM. Owing to the excellent cellular compatibility, endothelial cells can be cultured directly on the scaffold and the real-time inducing and recording of nitric oxide secretion under physiological and pathological conditions were achieved. This work renders a reliable sensing platform for real-time monitoring cytomechanical signaling during endothelial mechanotransduction and is expected to promote other related biological investigations based on three-dimensional cell culture.

[Acute toxicity test of the Li-Dan-He-Ji granules].

OBJECTIVE: To observe the acute toxic reaction of the Li-Dan-He-Ji granules, and to evaluate its safety. METHODS: Sixty C57BL6/J mice were randomly divided into normal control group, vehicle group and drug treatment group, with 10 females and 10 males in each group. According to the Technical guidelines for the study of toxicity of single drug administration, the maximum administration dosage (MAD) was used to intragastric administration of Li-Dan-He-Ji granules 0.04 mL/g (42.8 g/kg), three times within 24 hours, with an interval of 6 hours. The vehicle group was fed with the same pure water. The normal control group received no treatment. The mice were observed continuously for 14 days, and the appearance characteristics, behavioral activities, body weight changes and the number of deaths in each group were recorded. At the 14 days, blood samples were collected from the eyeballs, and routine blood tests such as white blood cell count (WBC), lymphocyte count (LYM), neutrophil count (NEU), lymphocyte percentage (LYM%), neutrophil percentage (NEU%), red blood cell count (RBC), hemoglobin (Hb), and platelet count (PLT) were performed. And alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr) and other biochemical indicators. The mice were then sacrificed, and the histopathological changes of liver and kidney were observed by hematoxylin-eosin (HE) staining. The organ indexes of heart, liver, spleen, lung, kidney and thymus were calculated. RESULTS: The median lethal dose (LD50) of Li-Dan-He-Ji granules were not obtained. During the MAD experiment, the animals in each group did not die, their behavioral activities were normal, and there was no significant change in liver and kidney histopathological examination. There were no significant differences in body weight, blood routine, biochemical indexes and organ index among all groups (all P > 0.05). The body weight (g) of normal control female and male group, vehicle female and male group and drug female and male group before administration were 18.96±1.14, 19.65±1.45, 19.33±1.30, 19.53±1.22, 19.28±1.69 and 19.48±1.28; 14 days after administration were 27.69±0.81, 28.19±2.22, 27.77±1.00, 27.88±1.85, 27.92±1.33 and 28.07±1.93, respectively. CONCLUSIONS: The Li-Dan-He-Ji granules have low oral toxicity, combined with clinical observation, can be safely used in infants.

Stretchable Sponge-Based Electrochemical Biosensor for Real-Time Sensing of Cells in Three-Dimensional Culture.

For the study of cell biology, real-time information on cell physiological processes will be more accurate and closer to the in vivo condition in a three-dimensional (3D) culture system. Although most reported 3D cell culture scaffolds can better mimic the in vivo dynamic microenvironment, the real-time analysis technique is deficient or lacking. Herein, a stretchable and conductive 3D scaffold is developed to construct an electrochemical biosensor for real-time monitoring of cell release in 3D culture under stimulation of drug stimulant and mechanical force. In our design, the polyurethane sponge (PU) dipped with conductive carbon ink (CC/PU) was used as a conductive scaffold, and gold nanoparticles (nano-Au) were electrodeposited on the CC/PU (nano-Au CC/PU) to improve the electrochemical sensing performance. The prepared nano-Au CC/PU scaffold exhibits a good electrocatalytic ability to H2O2 with a linear range from 20 nM to 43 µM. Due to the great biocompatibility, HeLa cells can be cultured directly on the nano-Au CC/PU and the in situ and real-time tracking of H2O2 secretion from cells was achieved. The results demonstrate that both the drug stimulant and mechanical force can rapidly activate the release of reactive oxygen species. This study indicates that the stretchable 3D sensing scaffold has good potential for cell biology research in an in vivo-like microenvironment and can be extensively used in the fields of tissue engineering, drug screening, and pathological research.

[Effects of Li-Dan-He-Ji on regulating oxidative stress and antagonising infantile cholestatic hepatic fibrosis].

OBJECTIVE: To explore the clinical effect of Li-Dan-He-Ji in the treatment of infantile cholestatic hepatic fibrosis. METHODS: Patients who met the diagnostic criteria of infantile cholestatic hepatic fibrosis in the department of integrated traditional Chinese and Western medicine and the department of gastroenterology of Wuhan Children's Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from January to December 2021 were included in the study by prospective randomized controlled trial. They were divided into the conventional treatment group and Li-Dan-He-Ji group according to the random number table. The patients in the conventional treatment group were given conventional treatment according to the guidelines. In the Li-Dan-He-Ji group, the self-made Chinese medicinal compound Li-Dan-He-Ji (prescription: Herba Artemisiae Scopariae, Fructus Forsythiae, Radix et Rhizoma Rhei preparata, Radix Polygoni Multiflori Preparata, Radix Paeoniae Rubra, Ramulus Cinnamomi, Fructus Aurantii, Rhizoma Atractylodis Macrocephalae, Fructus Schisandrae Chinensis, Carapax Trionycis, and Radix Glycyrrhizae) was given on the basis of the routine treatment, by oral, enema or nasal feeding, 60 mL each day, divided into 2 or 3 times, for 28 days. Outpatient follow-up was maintained for 4 weeks. Before and after treatment, serum liver fibrosis 4 items [type IV collagen (IV-C), hyaluronidase (HA), type III procollagen (PC III), laminin (LN)], liver function and cholestasis-related markers [total bilirubin (TBil), direct bilirubin (DBil), total bile acid (TBA), alkaline phosphatase (ALP), γ-glutamyl transpeptidase (γ-GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST)], oxidative stress markers [superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH)], liver stiffness measurement (LSM) detected by transient elastography (TE), aspartate aminotransferase-to-platelet ratio index (APRI), and liver and spleen retraction time were recorded in the two groups. RESULTS: During the observation period, a total of 40 cases of cholestatic hepatic fibrosis were treated, including 21 cases in the conventional treatment group and 19 cases in the Li-Dan-He-Ji group. Before treatment, the differences in serum liver fibrosis 4 items, serum liver function and cholestasis-related markers, oxidative stress indexes, LSM and APRI of the two groups were not statistically significant. After treatment, the liver fibrosis 4 items, liver function and cholestasis-related markers, LSM, and APRI were all significantly decreased in both groups, and the indexes in the Li-Dan-He-Ji group were significantly lower than those in the conventional treatment group [HA (ng/L): 165.81±21.57 vs. 203.87±25.88, PC III (µg/L): 69.86±9.32 vs. 81.82±7.39, IV-C (µg/L): 204.14±38.97 vs. 239.08±24.93, LN (µg/L): 162.40±17.39 vs. 190.86±15.97, TBil (µmol/L): 37.58±27.63 vs. 53.06±45.09, DBil (µmol/L): 20.55±19.34 vs. 30.08±27.39, ALP (U/L): 436.50±217.58 vs. 469.60±291.69, γ-GGT (U/L): 66.78±35.84 vs. 87.00±32.82, ALT (U/L): 64.75±50.53 vs. 75.20±50.19, AST (U/L): 77.25±54.23 vs. 96.80±59.77, TBA (µmol/L): 74.35±44.44 vs. 85.45±39.50, LSM (kPa): 5.24±0.39 vs. 7.53±3.16, APRI: 0.52±0.39 vs. 0.98±0.29, all P < 0.05]. After treatment, MDA in the two groups were significantly lower than those before treatment, and SOD and GSH were significantly higher than those before treatment. The level of SOD in the Li-Dan-He-Ji group was significantly higher than that in the conventional treatment group (kU/L: 64.56±6.69 vs. 51.58±5.98, P < 0.05). In addition, the liver retraction time (day: 20.13±10.97 vs. 24.33±13.46) and spleen retraction time (day: 25.93±13.01 vs. 29.14±14.52) in the Li-Dan-He-Ji group were significantly shorter than those in the conventional treatment group (both P < 0.05). CONCLUSIONS: The use of Li-Dan-He-Ji in the treatment of cholestatic hepatic fibrosis can effectively improve the indicators of cholestasis, hepatic fibrosis, oxidative stress and clinical symptoms in children.

Honeycomb-like nickel oxide-reduced graphene oxide based sensor for the electrochemical tracking of norepinephrine in neuronal cells.

Highly sensitive and specific detection and monitoring of trace norepinephrine (NE) in biological fluids and neuronal cell lines is essential for the investigation of pathogenesis of certain neurological diseases. Herein, we constructed a novel electrochemical sensor for real-time monitoring of NE released by PC12 cells based on glassy carbon electrode (GCE) modified with honeycomb-like nickel oxide (NiO)-reduced graphene oxide (RGO) nanocomposite. The synthesized NiO, RGO and the NiO-RGO nanocomposite were characterized using X-ray diffraction spectrogram (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The porous three-dimensional honeycomb-like structure of NiO and high charge transfer kinetics of RGO endowed the nanocomposite with excellent electrocatalytic activity, large surface area and good conductivity. The developed sensor exhibited superior sensitivity and specificity towards NE in a wide linear range from 20 nM to 14 µM and 14 µM-80 µM, with a low detection limit of 5 nM. The performances of the sensor in terms of excellent biocompatibility and high sensitivity allow it to be successfully employed in the tracking of NE release from PC12 cells under the stimulation of K+, providing an effective strategy for the real-time monitoring of cellular NE.

Real-time monitoring of 5-HT release from cells based on MXene hybrid single-walled carbon nanotubes modified electrode.

Serotonin (5-HT) is an essential inhibitory neurotransmitter in vivo that is critical for interneuronal communication of the nervous system. Herein, we constructed an electrochemical cell-sensing platform for 5-HT detection based on MXene/single-walled carbon nanotubes (SWCNTs) nanocomposite. The one-dimensional SWCNTs with good electrical conductivity are uniformly dispersed on the surface and intermediate layers of the two-dimensional MXene to form a tightly heterogeneous heterostructure. The synthesized MXene-SWCNTs could improve the stacking problem of MXene nanosheets and expose more active sites, effectively promoting the conductive properties and electrochemical activity of the composite. The fabricated MXene-SWCNTs/GCE possessed outstanding detection capability for 5-HT with a wide linear range of 4 nM-103.2 µM and a low detection limit of 1.5 nM. Moreover, the sensor was further applied for the real-time monitoring trace amount of 5-HT releasing from different cell lines, which confirmed its promising applications in 5-HT related physiological and pathological fields. MXene-SWCNTs/GCE was developed and applied for the real-time monitoring of trace amounts of 5-HT secreted from living cells.

Preparation of nanostructured PDMS film as flexible immunosensor for cortisol analysis in human sweat.

This work proposed a novel and flexible immunosensor for highly selective and sensitive determination of cortisol in sweat. The flexible electrode was developed by transferring multi-walled carbon nanotubes (MWCNTs) film on polydimethylsiloxane (PDMS) substrate and subsequent electrochemical deposition of Au nanoparticles (AuNPs) on the MWCNTs surface. The obtained AuNPs/MWCNTs/PDMS electrode was then covalently immobilized with anti-cortisol monoclonal antibody (Anti-Cmab) and blocked with BSA. Scanning electron microscope confirmed that MWCNTs have been firmly combined with PDMS and AuNPs distributed uniformly on the surface of MWCNTs. The PDMS-based sensor possesses a good mechanical stability against stretching, bending and twisting, displaying stable electrochemical performance under deformation. After optimizing the analytical parameters, the developed immunosensor allowed a facile quantification of cortisol in the range of 1 fg/mL-1 µg/mL with a detection limit of 0.3 fg/mL. The cortisol immunosensor was further used to evaluate cortisol levels in human sweat, and the results corresponded closely with commercially available chemiluminescence immunoassay (CLIA) method. Results indicated that the new cortisol immunosensor could provide an effective tool for the noninvasive, point of care measurement of sweat cortisol levels and is promise to be a wearable biosensor for the healthy monitoring.

Stretchable and Transparent Electrochemical Sensor Based on Nanostructured Au on Carbon Nanotube Networks for Real-Time Analysis of H2O2 Release from Cells.

Various electrochemical biosensors have been developed for direct and real-time recording of biomolecules released from living cells. However, since these traditional electrodes are commonly rigid and nonflexible, in situ monitoring of biochemical signals while cell deformation occurs remains a great challenge. Herein, we report a facile approach for the development of a stretchable and transparent electrochemical cell-sensing platform based on Au nanostructures (nano-Au) and carbon nanotube (CNT) films embedded in PDMS (nano-Au/CNTs/PDMS). The sandwich-like nanostructured network of nano-Au/CNTs endows the sensor with excellent mechanical stability and electrochemical performance. The obtained nano-Au/CNTs/PDMS electrode displays desired performance for H2O2 detection with a wide linear range (20 nM-25.8 µM) and low detection limit (8 nM). Owing to good biocompatibility and flexibility, HeLa and human umbilical vein endothelial cells can be directly cultured on the electrode and real-time monitoring of H2O2 release from cells under their stretched state was realized. The proposed strategy demonstrated in this work provides an effective way for design of stretchable sensors and more opportunities for sensing biomolecules from mechanically sensitive cells.

Flexible MXene/Silver Nanowire-Based Transparent Conductive Film with Electromagnetic Interference Shielding and Electro-Photo-Thermal Performance.

Transparent conductive film (TCF) is promising for optoelectronic instrument applications. However, designing a robust, stable, and flexible TCF that can shield electromagnetic waves and work in harsh conditions remains a challenge. Herein, a multifunctional and flexible TCF with effective electromagnetic interference shielding (EMI) performance and outstanding electro-photo-thermal effect is proposed by orderly coating Ti3C2Tx MXene and a silver nanowire (AgNW) hybrid conductive network using a simple and scalable solution-processed method. Typically, the air-plasma-treated polycarbonate (PC) film was sequentially spray-coated with MXene and AgNW to construct a highly conductive network, which was transferred and partly embedded into an ultrathin poly(vinyl alcohol) (PVA) film using spin coating coupled with hot pressing to enhance the interfacial adhesion. The peeled MXene/AgNW-PVA TCF exhibits an optimal optical and electrical performance of sheet resistance 18.3 Ω/sq and transmittance 52.3%. As a consequence, the TCF reveals an effective EMI shielding efficiency of 32 dB in X-band with strong interfacial adhesion and satisfactory flexibility. Moreover, the high electrical conductivity and localized surface plasmon resonance (LSPR) effect of hybrid conductive network endow the TCF with low-voltage-driven Joule heating performance and excellent photothermal effect, respectively, which can ensure the normal functioning under extreme cold condition. In view of the comprehensive performance, this work offers new solutions for next-generation transparent EMI shielding challenges.