Diagnostic value of adenohypophyseal MRI features in female children with precocious puberty

AIM

To evaluate the diagnostic value of adenohypophyseal magnetic resonance imaging (MRI) features for precocious puberty (PP) in female children and also to establish a non-invasive diagnostic approach in clinics.

MATERIALS AND METHODS

A total of 126 female children (37, 57, and 32 female children clinically diagnosed with central PP [CPP], incomplete PP [IPP], and controls, respectively) were enrolled in this study. Data were collected and analysed using analysis of variance. Pearson correlation and stepwise multivariate linear regression analysis were used to examine the association and build prediction models. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic efficacy.

RESULTS

The values of adenohypophysis volume (aPV), adenohypophysis height (aPH), and signal-intensity ratio (SIR), height, weight, and seven laboratory testing characteristics were correlated closely with the activation status of the hypothalamic-pituitary-gonad axis in the different groups (all p<0.05). Model 1 including aPV, weight, and aPH and Model 2 including SIR, aPV, and height were built to obtain predicted luteinising hormone (LH; R2 = 0.271) and LH/follicle stimulating hormone (FSH; R2 = 0.311). ROC analysis showed the predicted LH, predicted LH/FSH, and aPV were the top 3 best predictors in distinguishing CPP from controls (AUC = 0.969, 0.949, and 0.938) while predicted LH/FSH was the best predictor in distinguishing CPP from IPP and controls (AUC = 0.829 and 0.828).

CONCLUSION

The adenohypophysis volume itself and the prediction models including main adenohypophyseal MRI features increased diagnostic efficiency for PP and offered a non-invasive and credible diagnostic method.

Tumor diagnosis using carbon-based quantum dots: Detection based on the hallmarks of cancer

Carbon-based quantum dots (CQDs) have been shown to have promising application value in tumor diagnosis. Their use, however, is severely hindered by the complicated nature of the nanostructures in the CQDs. Furthermore, it seems impossible to formulate the mechanisms involved using the inadequate theoretical frameworks that are currently available for CQDs. In this review, we re-consider the structure-property relationships of CQDs and summarize the current state of development of CQDs-based tumor diagnosis based on biological theories that are fully developed. The advantages and deficiencies of recent research on CQDs-based tumor diagnosis are thus explained in terms of the manifestation of nine essential changes in cell physiology. This review makes significant progress in addressing related problems encountered with other nanomaterials.

Symmetry-Triggered Tunable Phosphorescence Lifetime of Graphene Quantum Dots in a Solid State

Studying the phosphorescent mechanisms of carbon nanostructures synthesized by the "bottom-up" approach is key to understanding the structure modulation and the interfacial properties of carbon nanostructures. In this work, the relationships among symmetry of precursors in the "bottom-up" synthesis, structures of products, and phosphorescence lifetimes of graphene quantum dots (GQDs) are studied. The symmetry matching of precursors in the formation of a D6h graphene-like framework is considered the key factor in controlling the separability of sp2 domains in GQDs. As the separability of sp2 domains in GQDs increases, the phosphorescence lifetimes (14.8-125.5 ms) of GQDs in the solid state can be tuned. Machine learning is used to define the degree of disorder (S) of the GQD structure, which quantitatively describes the different space groups of precursors. The negative correlation between S and the oscillator strength of GQDs is uncovered. Therefore, S can be recognized as reflective of oscillator strength in the GQD structure. Finally, based on the correlations found between the structures and phosphorescence lifetimes of GQDs, GQDs with an ultralong phosphorescence lifetime (28.5 s) are obtained. Moreover, GQDs with visible phosphorescence emission (435-618 nm) are synthesized.

The Synergistic Effect on the Mimetic Optical Structure of Feline Eyes toward Household Health Monitoring of Acute and Chronic Diseases

A breakthrough in the performance of bionic optical structures will only be achieved if we can obtain an in-depth understanding of the synergy mechanisms operating in natural optical structures and find ways to imitate them. In this work, inspired by feline eyes, an optical substrate that takes advantage of a synergistic effect that occurs between resonant and reflective structures was designed. The synergistic effect between the reflective and resonant components leads to a Raman enhancement factor (EF) of 1.16 × 107, which is much greater than that achieved using the reflective/resonant cavities on their own. Finite-difference time-domain (FDTD) simulations and experimental results together confirm that the mechanism of this synergistic effect is achieved by realizing multiple reflections and repeated absorptions of light, generating a strong local electric field. Thus, a 2-3 order of magnitude increase in sensitivity could be achieved. More importantly, with the homemade centrifugal device, above optical substrates were further used to develop a rapidly highly sensitive household health monitoring system (detection time <3 min). It can thus be used to give early warning of acute diseases with high risk (e.g., acute myocardial infarction (AMI) and cerebral peduncle). Due to the good reusability and storability (9% and 8% reduction in EF after washing 30 times and 9 months of storage, respectively) of the substrates, the substrates thus reduce detection costs (to ∼$1), making them much cheaper to use than the current gold-standard methods (e.g., ∼$16 for gout detection).

Correlation between iron metabolism indicators and programmed death ligand 1 expression in advanced non-small cell lung cancer

The dysregulation of iron metabolism is closely linked to the onset and progression of lung cancer. This study aimed to explore the association between iron metabolism indicators (serum iron, transferrin, ferritin) and the expression level of programmed death factor ligand 1 in primary lesions of advanced non-small cell lung cancer. A cohort of 62 patients, including 42 men and 20 women, was recruited from October 2022 to July 2023, all diagnosed with advanced non-small cell lung cancer, confirmed through radiographic imaging and histopathological analysis. Comprehensive clinical data (such as gender, age, familial lung cancer history, smoking history, pathological classification, clinical stage, etc.) and concentrations of fasting serum iron, transferrin, and ferritin were collected. Patients were categorized into PD-L1 negative (<1% expression) and programmed death ligand 1 (PD-L1) positive (≥1% expression) groups based on PD-L1 expression levels in tumor tissues. Subsequently, the correlation between levels of serum iron, transferrin, ferritin, and PD-L1 expression in advanced non-small cell lung cancer were examined. Patients in the PD-L1 positive group exhibited lower levels of peripheral serum iron and transferrin compared to those in the PD-L1 negative group (P<0.05). For patients exhibiting positive PD-L1 expression, a negative correlation was observed between PD-L1 expression and both serum iron and transferrin levels (r = -0.465, P=0.003; r = -0.447, P=0.005), and a positive correlation was noted between PD-L1 expression and ferritin levels (r=0.393, P=0.015). We conclude that in In patients with advanced non-small cell lung cancer, serum iron and transferrin levels can serve as partial predictors of PD-L1 expression; among those positive for PD-L1, a significant association exists between indicators of iron metabolism and PD-L1 expression.

Fast proton transport enables the magnetic relaxation response of graphene quantum dots for monitoring the oxidative environment in vivo

A magnetic relaxation switch (MRS) that targets small molecules such as H2O2 is difficult to realize because of the small size of the targets, which cannot gather enough MRS probes to form aggregates and generate a difference in magnetic relaxation times. Therefore, the development of small molecule-targeted MRS is strongly dependent on changes in the interfacial structure of the probe, which modulates the proton transport behavior near the probe. Herein, functionalized graphene quantum dots (GQDs) consisting of GQDs with disulfide bonds, polyethylene glycol (PEG), and paramagnetic Gd3+ were used as the MRS probe to sense H2O2. The structure of GQDs changed after reacting with H2O2. The PEG assembled a tube for transmitting changes in GQDs via proton transport and thus enabled the magnetic relaxation response of the probe towards H2O2. Pentaethylene glycol was experimentally and theoretically proven to have the strongest ability to transport protons. Such a probe can be applied in the differentiation of healthy and senescent cells/tissues using in vitro fluorescent imaging and in vivo magnetic resonance imaging. This work provides a reliable solution for building a proton transport route, which not only enables the response of the MRS probe towards the targets but also demonstrates the design of carbon nanostructures with proton transport behaviors.

Fabrication of Carbon-Based Quantum Dots via a "Bottom-Up" Approach: Topology, Chirality, and Free Radical Processes in "Building Blocks"

The discovery of carbon-based quantum dots (CQDs) has allowed opportunities for fluorescence bioimaging, tumor diagnosis and treatment, and photo-/electro-catalysis. Nevertheless, in the existing reviews related to the "bottom-up" approaches, attention is mainly paid to the applications of CQDs but not the formation mechanism of CQDs, which mainly derived from the high complexities during the synthesis of CQDs. Among the various synthetic methods, using small molecules as "building blocks", the development of a "bottom-up" approach has promoted the structural design, modulation of the photoluminescence properties, and control of the interfacial properties of CQDs. On the other hand, many works have demonstrated the "building blocks"-dependent properties of CQDs. In this review, from one of the most important variables, the relationships among intrinsic properties of "building blocks" and photoluminescence properties of CQDs are summarized. The topology, chirality, and free radical process are selected as descriptors for the intrinsic properties of "building blocks". This review focuses on the induction and summary of recent research results from the "bottom-up" process. Moreover, several empirical rules pertaining thereto are also proposed.

Association of body mass index and intestinal (faecal) Streptococcus in adults in Xining city, China P.R

Body mass index (BMI) and gut microbiota show significant interaction, but most studies on the relationship between BMI and gut microbiota have been done in Western countries. Relationships that are also identified in other cultural backgrounds are likely to have functional importance. Hence here we explore gut microbiota in adults living in Xining city (China P.R.) and relate results to subject BMI. Analysis of bacterial 16s rRNA gene was performed on faecal samples from participants with normal-weight (n=24), overweight (n=24), obesity (n=11) and type 2 diabetes (T2D) (n=8). The results show that unweighted but not weighted Unifrac distance was significantly different when gut microbiota composition was compared between the groups. Importantly, the genus Streptococcus was remarkably decreased in both obese subjects and subjects suffering from T2D, as compared to normal-weight subjects. Accordingly, strong association was identified between the genus Streptococcus and BMI and especially Streptococcus salivarius subsp. thermophiles was a major contributor in this respect. As previous studies have shown that Streptococcus salivarius subsp. thermophiles is also negatively associated with obesity in Western cohorts, our results suggest that this species is a potential probiotic for the prevention of obesity and related disorders.

[Advances of enhancers in regulating craniomaxillofacial development in mammals]

As a key regulatory element of gene differential expression, enhancer plays a crucial role in craniomaxillofacial development through regulating the spatiotemporal expression of target genes to promote tissue-specific differentiation. With the development of CRISPR and chromosome conformation capture technique, the function of enhancer and its regulatory mechanism has been explored in depth. This paper gave a systematic review on the mechanism of enhancer regulating target gene expression and the role of enhancer in oral craniofacial development and malformation.

Synergistic Effect of Oxygen- and Nitrogen-Containing Groups in Graphene Quantum Dots: Red Emitted Dual-Mode Magnetic Resonance Imaging Contrast Agents with High Relaxivity

Contrast agents (CAs) in magnetic resonance imaging generally involve the dissociative Gd³⁺. Because of the limited ligancy of Gd³⁺, the balance between Gd³⁺ coordination stability (reducing the concentration of dissociative Gd³⁺) and increases in the number of coordination water molecules (enhancing the relaxivity) becomes crucial. Herein, the key factor of the synergistic effect between the O- and N-containing groups of graphene quantum dots for the structural design of CAs with both high relaxivity and low toxicity was obtained. The nitrogen-doped graphene quantum dots (NGQDs) with an O/N ratio of 0.4 were selected to construct high-relaxivity magnetic resonance imaging (MRI)-fluorescence dual-mode CAs. The coordination stability of Gd³⁺ can be increased through the synergetic coordination of O- and N-containing groups. The synergetic coordination of O- and N-containing groups can result in the short residency time of the water ligand and achieve high relaxivity. The resulting CAs (called NGQDs-Gd) exhibit a high relaxivity of 32.04 mM^-1 s^-1 at 114 μT. Meanwhile, the NGQDs-Gd also emit red fluorescence (614 nm), which can enable the MRI-fluorescence dual-mode imaging as the CAs. Moreover, the bio-toxicity and tumor-targeting behavior of NGQDs-Gd were also evaluated, and NGQDs-Gd show potential in MRI-fluorescence imaging in vivo.

Investigation of a Highly Sensitive Surface-Enhanced Raman Scattering Substrate Formed by a Three-Dimensional/Two-Dimensional Graphene/Germanium Heterostructure

Three-dimensional graphene (3D-graphene) is used in surface-enhanced Raman spectroscopy (SERS) because of its plasmonic nanoresonator structure and good ability to interact with light. However, a thin (3-5 nm) layer of amorphous carbon (AC) inevitably appears as a template layer between the 3D-graphene and object substrate when the 3D-graphene layer is synthesized, weakening the enhancement factor. Herein, two-dimensional graphene (2D-graphene) is employed as a template layer to directly synthesize 3D-graphene on a germanium (Ge) substrate via plasma-assisted chemical vapor deposition, bypassing the formation of an AC layer. The interaction and photoinduced charge transfer ability of the 3D-graphene/Ge heterojunction with incident light are improved. Moreover, the high density of electronic states close to the Fermi level of the heterojunction induces the adsorbed probe molecules to efficiently couple to the 3D-graphene-based SERS substrate. Our experimental results imply that the lowest concentrations of rhodamine 6G and rhodamine B that can be detected on the 3D/2D-graphene/Ge SERS substrate correspond to 10^-10 M; for methylene blue, it is 10^-8 M. The detection limits of the 3D/2D-graphene/Ge SERS substrate with respect to 3-hydroxytyramine hydrochloride and melamine (in milk) are both less than 1 ppm. This work may provide a viable and convenient alternative method for preparing 3D-graphene SERS substrates. It also constitutes a new approach to developing SERS substrates with remarkable performance levels.

Magnetic graphene quantum dots facilitate closed-tube one-step detection of SARS-CoV-2 with ultra-low field NMR relaxometry

The rapid and sensitive diagnosis of the highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the crucial issues at the outbreak of the ongoing global pandemic that has no valid cure. Here, we propose a SARS-CoV-2 antibody conjugated magnetic graphene quantum dots (GQDs)-based magnetic relaxation switch (MRSw) that specifically recognizes the SARS-CoV-2. The probe of MRSw can be directly mixed with the test sample in a fully sealed vial without sample pretreatment, which largely reduces the testers' risk of infection during the operation. The closed-tube one-step strategy to detect SARS-CoV-2 is developed with home-made ultra-low field nuclear magnetic resonance (ULF NMR) relaxometry working at 118 μT. The magnetic GQDs-based probe shows ultra-high sensitivity in the detection of SARS-CoV-2 due to its high magnetic relaxivity, and the limit of detection is optimized to 248 Particles mL^‒1. Meanwhile, the detection time in ULF NMR system is only 2 min, which can significantly improve the efficiency of detection. In short, the magnetic GQDs-based MRSw coupled with ULF NMR can realize a rapid, safe, and sensitive detection of SARS-CoV-2.

Magnetic graphene quantum dots facilitate closed-tube one-step detection of SARS-CoV-2 with ultra-low field NMR relaxometry

The rapid and sensitive diagnosis of the highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the crucial issues at the outbreak of the ongoing global pandemic that has no valid cure. Here, we propose a SARS-CoV-2 antibody conjugated magnetic graphene quantum dots (GQDs)-based magnetic relaxation switch (MRSw) that specifically recognizes the SARS-CoV-2. The probe of MRSw can be directly mixed with the test sample in a fully sealed vial without sample pretreatment, which largely reduces the testers' risk of infection during the operation. The closed-tube one-step strategy to detect SARS-CoV-2 is developed with home-made ultra-low field nuclear magnetic resonance (ULF NMR) relaxometry working at 118 μT. The magnetic GQDs-based probe shows ultra-high sensitivity in the detection of SARS-CoV-2 due to its high magnetic relaxivity, and the limit of detection is optimized to 248 Particles mL^‒1. Meanwhile, the detection time in ULF NMR system is only 2 min, which can significantly improve the efficiency of detection. In short, the magnetic GQDs-based MRSw coupled with ULF NMR can realize a rapid, safe, and sensitive detection of SARS-CoV-2.

Sensitive, Reusable, Surface-Enhanced Raman Scattering Sensors Constructed with a 3D Graphene/Si Hybrid

Surface-enhanced Raman scattering (SERS) substrates based on graphene and its derivatives have recently attracted attention among those interested in the detection of trace molecules; however, these substrates generally show poor uniformity, an unsatisfactory enhancement factor, and require a complex fabrication process. Herein, we design and fabricate three-dimensional (3D) graphene/silicon (3D-Gr/Si) heterojunction SERS substrates to detect various types of molecules. Notably, the detection limit of 3D-Gr/Si can reach 10^-10 M for rhodamine 6G (R6G) and rhodamine B (RB), 10^-7 M for crystal violet (CRV), copper(II) phthalocyanine (CuPc), and methylene blue (MB), 10^-8 M for dopamine (DA), 10^-6 M for bovine serum albumin (BSA), and 10^-5 M for melamine (Mel), which is superior to most reported graphene-based SERS substrates. Besides, the proposed 3D-Gr/Si heterojunction SERS substrates can achieve a high uniformity with relative standard deviations (RSDs) of less than 5%. Moreover, the 3D-Gr/Si SERS substrates are reusable after washing with ethyl alcohol to remove the adsorbed molecules. These excellent SERS performances are attributed to the novel 3D structure and abundantly exposed atomically thin edges, which facilitate charge transfer between 3D-Gr and probe molecules. We believe that the 3D-Gr/Si heterojunction SERS substrates offer potential for practical applications in biochemical molecule detection and provide insight into the design of high-performance SERS substrates.

Graphene Quantum Dots with Pyrrole N and Pyridine N: Superior Reactive Oxygen Species Generation Efficiency for Metal-Free Sonodynamic Tumor Therapy

Those responsible for the development of sonosensitizers are faced with a dilemma between high sonosensitization efficacy and good biosecurity that limited the development of sonodynamic therapy (SDT). Herein, inspired by the intriguing therapeutic features of SDT and the potential catalytic activity of graphene quantum dots, the potential of N-doped graphene quantum dots (N-GQDs) to act as a sonosensitizer is demonstrated. The superior sonosensitization effect of N-GQDs is believed to be three to five times higher than that of traditional sonosensitizers (such as porphyrin, porphyrin Mn, porphyrin Zn, TiO₂ , etc.). More importantly, the sonochemical mechanism of N-GQDs is revealed. Pyrrole N and pyridine N are believed to form catalytic centers in sonochemical processing of N-GQDs. This knowledge is important from the perspective of understanding the structure-dependent SDT enhancement of carbon nanostructure. Moreover, N-GQDs modified by folic acid (FA-N-GQDs) show a high marker rate for tumor cells (greater than 96%). Both in vitro and in vivo therapeutic results have exhibited high tumor inhibition efficiency (greater than 90%) of FA-N-GQDs as sonosensitizers while the oxidative stress response of tumor cells is activated through the PEX pathway and induced apoptosis via the p53 pathway.

Imaging Cellular Aerobic Glycolysis using Carbon Dots for Early Warning of Tumorigenesis

Early warning of tumor formation is crucial for the classification, treatment, and prognosis of tumor patients. Here, a new strategy is reported, aimed at realizing this goal based on imaging aerobic glycolysis processes using nitrogen-doped carbon dots (N-CDs) as fluorescent probes. The intensity of the photoluminescence emitted by the N-CDs is specifically enhanced by nicotinamide adenine dinucleotide (NAD⁺ , oxidized) in the physiological environment. The N-CDs allow a few (five to ten) abnormal cells in spontaneous hepatocellular carcinoma models to be identified before the in situ development of tumor tissue. The N-CD probes can also distinguish tumor cells from normal cells and be used to evaluate their proliferation activity (with a specificity of up to 96.15% in 13 types of tumor cells and 90.90% in orthotopic xenograft models). The N-CDs are successfully used to monitor the invasion of tumor cells into neighboring tissues and body fluids in 49 clinical samples (with a sensitivity up to 79.31%). These included three vitreous body samples (from patients with retinoblastoma), 42 urine samples (22 patients clinically diagnosed with urothelium carcinoma and 20 healthy persons), and four hydrothorax samples (from patients with metastatic lesions).

Carbon-Based Quantum Dots with Solid-State Photoluminescent: Mechanism, Implementation, and Application

Carbon-based quantum dots (CQDs), including spherical carbon dots and graphene quantum dots, are an emerging class of photoluminescent (PL) materials with unique properties. Great progress has been made in the design and fabrication of high-performance CQDs, however, the challenge of developing solid-state PL CQDs have aroused great interest among researchers. A clear PL mechanism is the basis for the development of high-performance solid-state CQDs for light emission and is also a prerequisite for the realization of multiple practical applications. However, the extremely complex structure of a CQD greatly limits the understanding of the solid-state PL mechanism of CQDs. So far, a variety of models have been proposed to explain the PL of solid-state CQDs, but they have not been unified. This review summarizes the current understanding of the solid-state PL of solid-state CQDs from the perspective of energy band theory and electronic transitions. In addition, the common strategies for realizing solid-state PL in CQDs are also summarized. Furthermore, the applications of CQDs in the fields of light-emitting devices, anti-counterfeiting, fingerprint detection, etc., are proposed. Finally, a brief outlook is given, highlighting current problems, and directions for development of solid-state PL of CQDs.

Ultra-low noise graphene/copper/nylon fabric for electromagnetic interference shielding in ultra-low field magnetic resonance imaging

In ultra-low-field magnetic resonance imaging (ULF MRI) working in the micro-tesla magnetic field range, the superconducting quantum interference device (SQUID) as the signal detector is very susceptible to electromagnetic interference (EMI) so that the system normally works in a shielded room. However, the leakage of EMI in the shielded room may still seriously reduce the system performance. In order to improve the electromagnetic compatibility of the system, we designed a microwave absorbing composite, graphene/Cu/nylon fabric (GCN fabric). In this design, high shielding effectiveness and low-noise performance of the EMI shielding material are equally crucial due to the extremely sensitive detection with SQUID. The shielding effectiveness of 5-layer fabric ranges between 30 dB and 67 dB from 30 MHz to 3 GHz and its maximum appears at 60 MHz. Furthermore, GCN fabric introduces little extra system noise when applied in the ULF MRI system with magnetic field noise of 0.8 fT/Hz at 5 kHz. The SQUID unlocked tuned signal is thus increased by 33% and the signal-to-noise ratio of MRI image is increased by a factor of 4.3. In future, portable and inexpensive unshielded ULF MRI with low-noise might be realized by potential optimization on the component and preparation technology of GCN fabric.

Interface Engineering-Assisted 3D-Graphene/Germanium Heterojunction for High-Performance Photodetectors

Three-dimensional graphene (3D-Gr) with excellent light absorption properties has received enormous interest, but in conventional processes to prepare 3D-Gr, amorphous carbon layers are inevitably introduced as buffer layers that may degrade the performance of graphene-based devices. Herein, 3D-Gr is prepared on germanium (Ge) using two-dimensional graphene (2D-Gr) as the buffer layer. 2D-Gr as the buffer layer facilitates the in situ synthesis of 3D-Gr on Ge by plasma-enhanced chemical vapor deposition (PECVD) by promoting 2D-Gr nucleation and reducing the barrier height. The growth mechanism is investigated and described. The enhanced light absorption as confirmed by theoretical calculation and 3D-Gr/2D-Gr/Ge with a Schottky junction improves the performance of optoelectronic devices without requiring pre- and post-transfer processes. The photodetector constructed with 3D-Gr/2D-Gr/Ge shows an excellent responsivity of 1.7 A W^-1 and detectivity 3.42 × 10¹⁴ cm Hz^1/2 W^-1 at a wavelength of 1550 nm. This novel hybrid structure that incorporates 3D- and 2D-Gr into Ge-based integrated circuits and photodetectors delivers excellent performance and has large commercial potential.

Polarizing Graphene Quantum Dots toward Long-Acting Intracellular Reactive Oxygen Species Evaluation and Tumor Detection

The evaluation of intracellular reactive oxygen species (ROS) would greatly deepen the understanding of cell metabolism/proliferation and tumor detection. However, current long-acting level tracking techniques for intracellular ROS remain unsuited to practical applications. To solve this problem, we synthesized cyclotriphosphazene-doped graphene quantum dots (C-GQDs) whose quantum yield is highly sensitive to ROS (increased by 400% from 0.12 to 0.63). Electron cloud polarization of oxidized cyclotriphosphazene rings in C-GQDs is confirmed to account for this novel optical property by density functional theory calculations and experimental results. In combination with excellent biological stability, C-GQDs achieve a long-acting evaluation of intracellular ROS level (more than 72 h) with an accuracy of 98.3%. In addition, recognition rates exceeding 90% are demonstrated to be feasible for eight kinds of tumor cell lines cultured with C-GQDs, which can also be expanded to in vivo detection. C-GQDs also show a high recognition rate (82.33%) and sensitivity (79.65%) for tumor cells in blood samples.

"Self-Matched" Tribo/Piezoelectric Nanogenerators Using Vapor-Induced Phase-Separated Poly(vinylidene fluoride) and Recombinant Spider Silk

Flexible biocompatible mechanical energy harvesters are drawing increasing interest because of their high energy-harvesting efficiency for powering wearable/implantable devices. Here, a type of "self-matched" tribo-piezoelectric nanogenerators composed of genetically engineered recombinant spider silk protein and piezoelectric poly(vinylidene fluoride) (PVDF)-decorated poly(ethylene terephthalate) (PET) layers is reported. The PET layer serves as a shared structure and electrification layer for both piezoelectric and triboelectric nanogenerators. Importantly, the PVDF generates a strong piezo-potential that modifies the surface potential of the PET layer to match the electron-transfer direction of the spider silk during triboelectrification. A "vapor-induced phase-separation" process is developed to enhance the piezoelectric performance in a facile and "green" roll-to-roll manufacturing fashion. The devices show exceptional output performance and energy transformation efficiency among currently existing energy harvesters of similar sizes and exhibit the potential for large-scale fabrication and various implantable/wearable applications.

Coordinating capillary infiltration with anodic oxidation: a multi-functional strategy for electrochemical fabrication of graphene

Coordinating the capillarity infiltration with anodic oxidation enables electrochemical fabrication of various graphene materials at different temperatures.

Graphite-N Doped Graphene Quantum Dots as Semiconductor Additive in Perovskite Solar Cells

Efficient charge transport is especially important for achieving high performance of perovskite solar cells (PSCs). Here, molecularly designed graphite-nitrogen doped graphene quantum dots (GN-GQDs) act as a functional semiconductor additive in perovskite film. GN-GQDs with abundant N active sites participate in the crystallization of perovskite film and effectively passivate the grain boundary (GB) trap states by Lewis base/acid interaction. Moreover, the semiconductive GN-GQDs at GBs exhibit matched energy structure with the perovskite, which facilitate the charge transport at GBs. GN-GQDs also show n-type dopant property to upshift the Fermi energy level of perovskite films. It largely improves the charge transport in PSCs and reduces the interface recombination at the same time. Profiting from these advantages, inverted planar PSCs with NiO/perovskite/PCBM/BCP structure achieves high efficiency of 19.8% with no hysteresis phenomenon. GN-GQDs modified PSCs also show high stability even without encapsulation, benefiting from the protected GBs and more hydrophobic surface of the modified film. This work highlights a judicious design method of GQDs additive to satisfy efficient and stable PSCs.

High Weight-Specific Power Density of Thin-Film Amorphous Silicon Solar Cells on Graphene Papers

Flexible thin-film solar cells with high weight-specific power density are highly desired in the emerging portable/wearable electronic devices, solar-powered vehicles, etc. The conventional flexible metallic or plastic substrates are encountered either overweight or thermal and mechanical mismatch with deposited films. In this work, we proposed a novel substrate for flexible solar cells based on graphene paper, which possesses the advantages of being lightweight and having a high-temperature tolerance and high mechanical flexibility. Thin-film amorphous silicon (a-Si:H) solar cells were constructed on such graphene paper, whose power density is 4.5 times higher than that on plastic polyimide substrates. In addition, the a-Si:H solar cells present notable flexibility whose power conversion efficiencies show little degradation when the solar cells are bent to a radius as small as 14 mm for more than 100 times. The application of this unique flexible substrate can be extended to CuInGaSe and CdTe solar cells and other thin-film devices requiring high-temperature processing.

Ultrafast extreme rejuvenation of metallic glasses by shock compression

Structural rejuvenation of glasses not only provides fundamental insights into their complicated dynamics but also extends their practical applications. However, it is formidably challenging to rejuvenate a glass on very short time scales. Here, we present the first experimental evidence that a specially designed shock compression technique can rapidly rejuvenate metallic glasses to extremely high-enthalpy states within a very short time scale of about 365 ± 8 ns. By controlling the shock stress amplitude, the shock-induced rejuvenation is successfully frozen at different degrees. The underlying structural disordering is quantitatively characterized by the anomalous boson heat capacity peak of glasses. A Deborah number, defined as a competition of time scales between the net structural disordering and the applied loading, is introduced to explain the observed ultrafast rejuvenation phenomena of metallic glasses.

Probiotics maintain intestinal secretory immunoglobulin A levels in healthy formula-fed infants: a randomised, double-blind, placebo-controlled study

Formula-fed infants are more susceptible to infectious diseases because they lack the maternal immune factors transferred from breast milk, while their own immune system is still immature. As timely probiotic administration was suggested to promote immune system development in formula-fed infants, this study aimed at assessing the safety and the effects of a probiotic supplement (Bifidobacterium infantis R0033, Bifidobacterium bifidum R0071, and Lactobacillus helveticus R0052) on mucosal immune competence and digestive function in formula-fed infants. Healthy infants (3.5-6 months old) were randomised to receive either probiotic- (n=66) or placebo-supplemented (n=66) formula once a day for four weeks. In the probiotics group, faecal secretory immunoglobulin A (SIgA) levels remained similar between visit 2 (baseline; V2) and visit 3 (end-of-treatment; V3), but decreased in the placebo group. Changes in SIgA levels following treatment (log₁₀ΔV3-V2 [95%CI]) between the probiotic and placebo groups were statistically significant (23 ng/dl [-57;102] and -137 ng/dl [-212;-62], respectively (P=0.0044; ANCOVA)). While log₁₀ΔV3-V2 [95%CI] for salivary SIgA levels increased in both groups, this trend was more pronounced in the probiotics than in the placebo group with an increase of 123 ng/dl [9;236] and 37 ng/dL [-72;147], respectively (P=0.2829; ANCOVA). The weekly average number of stools/day was significantly higher in the probiotics group compared to placebo during the last week of treatment for the per protocol population. There was no difference in microbiota composition or anthropometric parameters between groups. No serious adverse event was reported, and all adverse events were mild and unrelated to the product or study. Our results show that formula-fed infants receiving probiotics maintained higher faecal SIgA levels at the end of the four-week treatment period, suggesting a positive effect of probiotics on SIgA production. This study demonstrates the safety of this probiotic formulation in infants. Formula-fed infants may benefit from probiotics supplementation to sustain the development of mucosal immunity.

miR-33a expression sensitizes Lgr5+ HCC-CSCs to doxorubicin via ABCA1

Cancer stem cells (CSCs) are responsible for the unrestrained cell growth and chemo-resistance of malignant tumors. Reports about miR-33a in different type of cancer are limited, and it remains elusive whether there is a link between miR-33a and chemo-resistance of CSCs. Here we report that Lgr5+ hepatocellular carcinoma (HCC) cells from primary tissues and cell lines behave similarly to CSCs and are chemo-resistant to doxorubicin. Significantly, reduced miR-33a expression is associated with the chemo-resistance of Lgr5+ HCC-CSCs, accompanied by an overexpression of ABCA1 which is identified as target of miR-33a by mainly using miRNA luciferase assay and western-blotting. We demonstrate that down-regulation of miR-33a expression directly contributes to chemo-resistance of Lgr5+ HCC-CSCs, and restoring miR-33a expression sensitizes them to doxorubicin via apoptosis by mainly using TUNEL assay, soft agar colony formation assay and xenograft assay. Additionally, reduced miR-33a expression in HCC tissues is associated with chemo-response and poor patient survival, which suggests the therapeutic potential of miR-33a. In conclusion, our work indicates that ectopic miR-33a expression sensitizes Lgr5+ HCC-CSCs to doxorubicin via direct targeting ABCA1, which sheds new light on understanding the mechanism of chemo-resistance in HCC-CSCs and contributes to development of potential therapeutics against HCC.

Cycling-Induced Capacity Increase of Graphene Aerogel/ZnO Nanomembrane Composite Anode Fabricated by Atomic Layer Deposition

Zinc oxide (ZnO) nanomembranes/graphene aerogel (GAZ) composites were successfully fabricated via atomic layer deposition (ALD). The composition of GAZ composites can be controlled by changing the number of ALD cycles. Experimental results demonstrated that the anode made from GAZ composite with ZnO nanomembrane of 100 ALD cycles exhibited highest specific capacity and best rate performance. A capacity increase of more than 2 times during the first 500 cycles was observed, and a highest capacity of 1200 mAh g^-1 at current density of 1000 mA g^-1 was observed after 500 cycles. On the basis of detailed electrochemical investigations, we ascribe the remarkable cycling-induced capacity increase to the alloying process accompanied by the formation of a polymer layer resulting from kinetically activated electrolyte degradation at low voltage regions.

Promising Fast Energy Transfer System Between Graphene Quantum Dots and the Application in Fluorescent Bioimaging

Tunable photoluminescence performance of graphene quantum dots (GQDs) is one of the most important topics for the development of GQDs. In this paper, we report lattice-doped GQDs (boron-doped GQDs (B-GQDs) and phosphorus-doped GQDs (P-GQDs)). Because of the matched band structure, the fast energy transfer between blue-emitted B-GQDs (emission wavelength: 460 nm) and orange-emitted P-GQDs (emission wavelength: 630 nm) can induce an efficient fluorescence emission in P-GQDs once B-GQDs are excited under the optimal excitation wavelength of 460 nm. Moreover, with the effective energy transfer, the quantum yield of P-GQDs increased to 0.48, which is much higher than that of pure P-GQDs. We also demonstrated the potentials of this system for fluorescent bioimaging in vitro.

Electrochemical Strategy for Flexible and Highly Conductive Carbon Films: The Role of 3-Dimensional Graphene/Graphite Aggregates

Conductive carbon films with good flexibility are ever-increasingly desired for electronics. Previous efforts relying on graphene films to achieve this required special treatment to create wrinkles in the lamellar stacking sheet structure. Here, films with a wrinkled structure were facilely fabricated from electrochemically derived 3-dimiensional (3D) graphene/graphite aggregates, exhibiting excellent flexibility and high conductivity. The resulting films are very flexible that can bear 1000 times fold without breakage. A high conductivity up to 100 000 S m^-1 can be achieved after a relatively low temperature annealing (1000 °C) owing to its low content of defect and large size of graphene/graphite aggregates. Based on these properties, an electrothermal heater assembled from these composite films supplies a high saturated temperature (423 °C) at low working voltages (4 V). These superior properties, together with the advantage of environmental friendliness and facile and large-scale fabrication, endow the composite films with great potential applications in flexible electronics.

Seamless lateral graphene p-n junctions formed by selective in situ doping for high-performance photodetectors

Lateral graphene p–n junctions are important since they constitute the core components in a variety of electronic/photonic systems. However, formation of lateral graphene p–n junctions with a controllable doping levels is still a great challenge due to the monolayer feature of graphene. Herein, by performing selective ion implantation and in situ growth by dynamic chemical vapor deposition, direct formation of seamless lateral graphene p–n junctions with spatial control and tunable doping is demonstrated. Uniform lattice substitution with heteroatoms is achieved in both the boron-doped and nitrogen-doped regions and photoelectrical assessment reveals that the seamless lateral p–n junctions exhibit a distinct photocurrent response under ambient conditions. As ion implantation is a standard technique in microelectronics, our study suggests a simple and effective strategy for mass production of graphene p–n junctions with batch capability and spatial controllability, which can be readily integrated into the production of graphene-based electronics and photonics.

Fabricating lateral graphene p–n junctions with controlled doping levels is instrumental to realize ultrafast and efficient optoelectronic devices. Here, the authors report a seamless graphene based photodetector doped by selective ion implantation and in-situ chemical vapour deposition.

Phase-Separation-Induced PVDF/Graphene Coating on Fabrics toward Flexible Piezoelectric Sensors

Clothing-integrated piezoelectric sensors possess great potential for future wearable electronics. In this paper, we reported a phase-separation approach to fabricate flexible piezoelectric sensors based on poly(vinylidene fluoride) (PVDF)/graphene composite coating on commercially available fabrics (PVDF/graphene@F). The structural units of -CH₂- and -CF₂- of PVDF chains were arranged directionally due to the structural induction of graphene and water during phase separation, which is the key for electroactive phase enrichment. In optimized case, integrating into fabric substrates endows the phase-out PVDF/graphene composite coating 4 times higher voltage output than its film counterpart. Piezoelectric sensor based on PVDF/graphene@F exhibits a sensitivity of 34 V N^-1, which is higher than many reports. It also shows low detecting threshold (0.6 mN), which can be applied to distinguish the voices or monitor the motion of body. This simple and effective approach toward PVDF/graphene@F with excellent flexibility provides a promising route toward the development of wearable piezoelectric sensors.

Three-dimensional cross-linking composite of graphene, carbon nanotubes and Si nanoparticles for lithium ion battery anode

Various graphene-based Si nanocomposites have been reported to improve the performance of active materials in Li-ion batteries. However, these candidates still yield severe capacity fading due to the electrical disconnection and fractures caused by the huge volume changes over extended cycles. Therefore, we have designed a novel three-dimensional cross-linked graphene and single-wall carbon nanotube structure to encapsulate the Si nanoparticles. The synthesized three-dimensional structure is attributed to the excellent self-assembly of carbon nanotubes with graphene oxide as well as a thermal treatment process at 900 °C. This special structure provides sufficient void spaces for the volume expansion of Si nanoparticles and channels for the diffusion of ions and electrons. In addition, the cross-linking of the graphene and single-wall carbon nanotubes also strengthens the stability of the structure. As a result, the volume expansion of the Si nanoparticles is restrained. The specific capacity remains at 1450 mAh g^-1 after 100 cycles at 200 mA g^-1. This well-defined three-dimensional structure facilitates superior capacity and cycling stability in comparison with bare Si and a mechanically mixed composite electrode of graphene, single-wall carbon nanotubes and silicon nanoparticles.

Facile and Highly Effective Synthesis of Controllable Lattice Sulfur-Doped Graphene Quantum Dots via Hydrothermal Treatment of Durian

Recently, the biomass "bottom-up" approach for the synthesis of graphene quantum dots (GQDs) has attracted broad interest because of the outstanding features, including low-cost, rapid, and environmentally friendly nature. However, the low crystalline quality of products, substitutional doping with heteroatoms in lattice, and ambiguous reaction mechanism strongly challenge the further development of this technique. Herein, we proposed a facile and effective strategy to prepare controllable sulfur (S) doping in GQDs, occurring in a lattice substitution manner, by hydrothermal treatment of durian with platinum catalyst. S atoms in GQDs are demonstrated to exist in the thiophene structure, resulting in good optical and chemical stabilities, as well as ultrahigh quantum yield. Detailed mechanism of the hydrothermal reaction progress was investigated. High-efficiency reforming cyclization provided by platinum was evidenced by the coexistence of diversified sp²-fused heterocyclic compounds and thiophene derivatives. Moreover, we also demonstrated that saccharides in durian with small molecular weight (<1000 Da) is the main carbon source for the forming GQDs. Because of the desulfurizing process, controllable photoluminescence properties could be achieved in the as-prepared GQDs via tuning doping concentrations.

Electrochemical Cutting in Weak Aqueous Electrolytes: The Strategy for Efficient and Controllable Preparation of Graphene Quantum Dots

The controllable and efficient electrochemical preparation of highly crystalline graphene quantum dots (GQDs) in an aqueous system is still challenging. Here, we developed a weak electrolyte-based (typically an ammonia solution) electrochemical method to enhance the oxidation and cutting process and therefore achieve a high yield of GQDs. The yield of GQDs (3-8 nm) is 28%, approximately 28 times higher than the yield of GQDs prepared by other strong electrolytes. The whole preparation process can be accomplished within 2 h because of the effective free radical oxidation process and the suppressed intercalation-induced exfoliation in weakly ionized aqueous electrolytes. The GQDs also showed excellent crystallinity which is obviously better than the crystallinity of GQDs obtained via bottom-up approaches. Moreover, amino-functionalization of GQDs can be realized by manipulating the electrolyte concentration. We further demonstrate that the proposed method can also be expanded to other weak electrolytes (such as HF and H₂S) and different anode precursor materials (such as graphene/graphite papers, carbon fibers, and carbon nanotubes).

Selective CD28 Blockade Results in Superior Inhibition of Donor-Specific T Follicular Helper Cell and Antibody Responses Relative to CTLA4-Ig

Donor-specific antibodies (DSAs) are a barrier to improved long-term outcomes after kidney transplantation. Costimulation blockade with CTLA4-Ig has shown promise as a potential therapeutic strategy to control DSAs. T follicular helper (Tfh) cells, a subset of CD4⁺ T cells required for optimal antibody production, are reliant on the CD28 costimulatory pathway. We have previously shown that selective CD28 blockade leads to superior allograft survival through improved control of CD8⁺ T cells relative to CTLA4-Ig, but the impact of CD28-specific blockade on CD4⁺ Tfh cells is unknown. Thus, we identified and characterized donor-reactive Tfh cells in a murine skin transplant model and then used this model to evaluate the impact of selective CD28 blockade with an anti-CD28 domain antibody (dAb) on the donor-specific Tfh cell-mediated immune response. We observed that the anti-CD28 dAb led to superior inhibition of donor-reactive CXCR5⁺ PD-1^high Tfh cells, CD95⁺ GL7⁺ germinal center B cells and DSA formation compared with CTLA4-Ig. Interestingly, donor-reactive Tfh cells differentially upregulated CTLA4 expression, suggesting an important role for CTLA4 in mediating the superior inhibition observed with the anti-CD28 dAb. Therefore, selective CD28 blockade as a novel approach to control Tfh cell responses and prevent DSA after kidney transplantation warrants further study.

Prevalence of honeybee viruses in different regions of China and Argentina

Honeybees are threatened by various pathogens and parasites. More than 18 viruses have been described in honeybees and many of them have been detected in China and Argentina. In China, both Apis cerana and Apis mellifera are raised. In Argentina, beekeepers raise different ecotypes of A. mellifera: European honeybees (in both temperate and subtropical regions) and Africanised honeybees (in subtropical areas only). A thorough study was carried out in both China and Argentina to analyse the current virus presence and distribution in different climatic zones and gather information on different bee species/subspecies. Adult honeybees were collected from apiaries in temperate and subtropical regions of China (including areas with exclusive populations of A. mellifera, areas where A. mellifera and A. cerana co-exist, and areas with exclusive populations of A. cerana) and Argentina. Six viruses, namely, deformed wing virus (DWV), black queen cell virus (BQCV), sacbrood virus (SBV), chronic bee paralysis virus (CBPV), acute bee paralysis virus (ABPV) and Israeli acute paralysis virus (IAPV) were detected in China, both in A. cerana and in A. mellifera, while four viruses (DWV, BQCV, CBPV and ABPV) were present in Argentina. Interestingly, multiple infections were commonly found in China, with up to five different viruses co-circulating in some colonies without apparent abnormalities. In this study, no Chinese samples were positive for slow bee paralysis virus. The most prevalent viruses were BQCV (China) and DWV (Argentina). Kashmir bee virus was absent from samples analysed for both countries.

Polyketides with different post-modifications from desert endophytic fungus Paraphoma sp

Three new polyketides 4,6,8-trihydroxy-5-methyl-3,4-dihydronaphthalen-1(2H)-one (1), 5,7-dihydroxy-3-(1-hydroxyethyl)-3,4-dimethylisobenzofuran-1(3H)-one (2) and 1-(4-hydroxy-6-methoxy-1,7-dimethyl-3-oxo-1,3-dihydroisobenzofuran-1-yl) ethyl acetate (3) together with seven known analogues (4-10) were isolated from desert endophytic fungus Paraphoma sp. The structures of these compounds were elucidated by analysis of NMR data. The absolute configuration of (1-3) was established on the basis of CD experiments. The possible biosynthetic pathway of compounds (1-10) was suggested, which implied that these secondary metabolites might be originated from polyketide biosynthesis with different post-modification reactions. Compounds 2, and 5-8 were evaluated for bioactivities against plant pathogen A. solani, whereas none of them displayed any biological effects. In addition, compounds 1, 2 and 5-10 were also tested for cytotoxic activities against three human cancer cell lines (HepG2 cells, MCF-7 cells and Hela cells) without biological effects.

Extreme polyandry aids the establishment of invasive populations of a social insect

Although monandry is believed to have facilitated the evolution of eusociality, many highly eusocial insects have since evolved extreme polyandry. The transition to extreme polyandry was likely driven by the benefits of within-colony genetic variance to task specialization and/or disease resistance, but the extent to which it confers secondary benefits, once evolved, is unclear. Here we investigate the consequences of extreme polyandry on the invasive potential of the Asian honey bee, Apis cerana. In honey bees and other Hymenoptera, small newly founded invasive populations must overcome the genetic constraint of their sex determination system that requires heterozygosity at a sex-determining locus to produce viable females. We find A. cerana queens in an invasive population mate with an average of 27 males (range 16-42) that would result in the founding queen/s carrying 75% of their source population's sex alleles in stored sperm. This mating frequency is similar to native-range Chinese A. cerana (mean 29 males, range 19-46). Simulations reveal that extreme polyandry reduces the risk, relative to monandry or moderate polyandry, that colonies produce a high incidence of inviable brood in populations that have experienced a founder event, that is, when sex allele diversity is low and/or allele frequencies are unequal. Thus, extreme polyandry aids the invasiveness of A. cerana in two ways: (1) by increasing the sex locus allelic richness carried to new populations with each founder, thereby increasing sex locus heterozygosity; and (2) by reducing the population variance in colony fitness following a founder event.

Tunable amplified spontaneous emission in graphene quantum dots doped cholesteric liquid crystals

Graphene quantum dots (GQDs) have received much research attention, because of their useful structure and optical absorption/emission. We report the tunable amplified spontaneous emission (ASE) in GQD-doped cholesteric liquid crystal (CLC), which to the best of our knowledge has not been previously observed. The GQDs are uniformly dispersed with a weight ratio of 0.5 wt.% in CLC. Under optical excitation, typical ASE is triggered in the system at pump energies greater than 1.25 mJ cm^-2. The emission peak at the long wavelength edge of the photonic bandgap shifts from 662 to 669 nm, as the working temperature is increased from 50 to 90 °C. The preparation of the combined GQDs and CLC is simple and low-cost, and the resulting material is photostable and non-toxic. Combining the GQD gain material with the self-assembled CLC resonator has potential in the fabrication of ASE source and laser devices.

Single-step One-pot Synthesis of TiO2 Nanosheets Doped with Sulfur on Reduced Graphene Oxide with Enhanced Photocatalytic Activity

A hybrid photocatalyst based on anatase TiO₂ was designed by doping TiO₂ with sulfur and incorporating reduced graphene oxide (TiO₂-S/rGO hybrid), with an aim to narrow the band gap to potentially make use of visible light and decrease the recombination of excitons, respectively. This TiO₂-S/rGO hybrid was successfully synthesized using a one-pot hydrothermal method via single-step reaction. The structure and morphology of the TiO₂-S/rGO hybrid catalyst was carefully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Its photocatalytic reactivity was evaluated by the degradation of methyl blue. The results showed that both the doping of sulfur and the introduction of rGO worked as designed, and the TiO₂-S/rGO hybrid exhibited high photocatalytic activity under simulated sunlight. Considering both the facile and scalable reaction to synthesize TiO₂-S/rGO hybrid, and its excellent photocatalytic performance, such TiO₂-S/rGO hybrids are expect to find practical applications in environmental and energy sectors.

C3 N-A 2D Crystalline, Hole-Free, Tunable-Narrow-Bandgap Semiconductor with Ferromagnetic Properties

Graphene has initiated intensive research efforts on 2D crystalline materials due to its extraordinary set of properties and the resulting host of possible applications. Here the authors report on the controllable large-scale synthesis of C₃ N, a 2D crystalline, hole-free extension of graphene, its structural characterization, and some of its unique properties. C₃ N is fabricated by polymerization of 2,3-diaminophenazine. It consists of a 2D honeycomb lattice with a homogeneous distribution of nitrogen atoms, where both N and C atoms show a D_6h -symmetry. C₃ N is a semiconductor with an indirect bandgap of 0.39 eV that can be tuned to cover the entire visible range by fabrication of quantum dots with different diameters. Back-gated field-effect transistors made of single-layer C₃ N display an on-off current ratio reaching 5.5 × 10¹⁰ . Surprisingly, C₃ N exhibits a ferromagnetic order at low temperatures (<96 K) when doped with hydrogen. This new member of the graphene family opens the door for both fundamental basic research and possible future applications.

Insights into the Oxidation Mechanism of sp2-sp3 Hybrid Carbon Materials: Preparation of a Water-Soluble 2D Porous Conductive Network and Detectable Molecule Separation

A thorough investigation of the oxidation mechanism of sp²-sp³ hybrid carbon materials is helpful for the morphological trimming of graphene. Here, porous graphene (PGN) was obtained via a free radical oxidation process. We further demonstrated the difference between traditional and free radical oxidation processes in sp²-sp³ hybrid carbon materials. The sp³ part of graphene oxide was oxidized first, and well-crystallized sp² domains were reserved, which is different from the oxidation mechanism in a traditional approach. The obtained PGN shows excellent performance in the design of PGN-based detectable molecule separation or other biomedical applications.