Microglial forkhead box O3a deficiency attenuates LPS-induced neuro-inflammation and depressive-like behaviour through regulating the expression of peroxisome proliferator-activated receptor-γ.

BACKGROUND AND PURPOSE: Depression is closely linked with microglial activation and neuro-inflammation. Peroxisome proliferator-activated receptor-γ (PPAR-γ) plays an important role in M2 activation of microglia. Forkhead box (FOX) O3a has been implicated in the regulation of mood-relevant behaviour. However, little is known about the inflammatory mechanisms of in the microglia of the brain. Here, we have investigated the role of microglial FOXO3a/PPAR-γ in the development of depression. EXPERIMENTAL APPROACH: The effect of FOXO3a on microglia inflammation was analysed in vitro and in lipopolysaccharide (LPS)-induced depression-like behaviours in vivo. ChIP-seq and Dual-luciferase reporter assays were used to confirm the interaction between FOXO3a and PPAR-γ. Behavioural changes were measured, while inflammatory cytokines, microglial phenotype and morphological properties were determined by ELISA, qRT-PCR, western blotting and immunostaining. KEY RESULTS: Overexpression of FOXO3a significantly attenuated expression of PPAR-γ and enhanced the microglial polarization towards the M1 phenotype, while knockdown of FOXO3a had the opposite effect. FOXO3a binds to the promoters of PPAR-γ and decreases its transcription activity. Importantly, deacetylation and activation of FOXO3a regulate LPS-induced neuro-inflammation by inhibiting the expression of PPAR-γ in microglia cells, supporting the antidepressant potential of histone deacetylase inhibitors. Microglial FOXO3a deficiency in mice alleviated LPS-induced neuro-inflammation and depression-like behaviours but failed to reduce anxiety behaviour, whereas pharmacological inhibition of PPAR-γ by GW9662 restored LPS-induced microglial activation and depressive-like behaviours in microglial FOXO3a-deficient mice. CONCLUSION AND IMPLICATIONS: FOXO3a/PPAR-γ axis plays an important role in microglial activation and depression, identifying a new therapeutic avenue for the treatment of major depression.

Modulation of macrophage polarization by secondary cross-linked hyaluronan-dopamine hydrogels.

The inflammatory response plays a critical role in standard tissue repair processes, wherein active modulation of macrophage polarization is necessary for wound healing. Dopamine, a mussel-inspired bioactive material, is widely involved in wound healing, neural/bone/myocardial regeneration, and more. Recent studies indicated that dopamine-modified biomaterials can potentially alter macrophages polarization towards a pro-healing phenotype, thereby enhancing tissue regeneration. Nevertheless the immunoregulatory activity of dopamine on macrophage polarization remains unclear. This study introduces a novel interpenetrating hydrogel to bridge this research gap. The hydrogel, combining varying concentrations of oxidized dopamine with hyaluronic acid hydrogel, allows precise regulation of mechanical properties, antioxidant bioactivity, and biocompatibility. Surprisingly, both in vivo and in vitro outcomes demonstrated that dopamine concentration modulates macrophage polarization, but not linearly. Lower concentration (2 mg/mL) potentially decrease inflammation and facilitate M2 type macrophage polarization. In contrast, higher concentration (10 mg/mL) exhibited a pro-inflammatory tendency in the late stages of implantation. RNA-seq analysis revealed that lower dopamine concentrations induced the M1/M2 transition of macrophages by modulating the NF-κB signaling pathway. Collectively, this research offers valuable insights into the immunoregulation effects of dopamine-integrated biomaterials in tissue repair and regeneration.

Analysis of telomere length and the relationship with neurocognitive functions in euthymic bipolar disorder: A cross-sectional pilot study.

BACKGROUND: Telomere shortening has been considered a potential biological marker related to disease susceptibility and aging in psychiatric disorders. However, the relationship between telomere length and bipolar disorder (BD-I and BD-II) is uncertain. Moreover, whether telomere shortening is an independent factor of cognitive impairment in BD patients is still inconclusive. METHODS: We explore telomere length and cognitive function in patients with bipolar disorder and the relationship between them. We enrolled three groups (35 patients with euthymic BD-I, 18 with euthymic BD-II, and 38 healthy controls). Telomere length was measured by fluorescent quantitative polymerase chain reaction (q-PCR), and cognitive function was evaluated by the MATRICS Consensus Cognitive Battery (MCCB). SPSS 24.0 was used for statistical analysis. RESULTS: The telomere length of euthymic patients with BD-I and BD-II was shorter than that of healthy controls (F = 8.228, P = 0.001, η2 = 0.176). Telomere length was not significantly different between BD-I and BD-II. Compared to HCs, poor performance was detected in attention and vigilance in BD-I patients (F = 3.473, P = 0.036). Working memory was positively correlated with telomere length in BD-II patients (Beta = 0.5, P = 0.041, Adjusted R2 = 0.2). CONCLUSIONS: The current study provided evidence of shortened telomere length in euthymic BD patients, indicating that telomere shortening might be a promising biomarker of susceptibility to bipolar disorder. The telomere length predicted the working memory in BD-II patients. Further studies are needed to clarify the role of accelerated aging on cognitive functioning in a young group of patients with BD.

Case report of non-tracheal intubation-an alternative for postpneumonectomy patients undergoing contralateral pulmonary resection.

BACKGROUND: Surgery on the contralateral or other lungs after pneumonectomy on one side is highly challenging and complex. It is critical to creating conditions for fluent surgical maneuvers while ensuring adequate ventilation for a patient during such an operation in the same chest cavity that appears incompatible. CASE PRESENTATION: We have reported herein the case of a patient who, following a left pneumonectomy, underwent a right upper pulmonary nodule wedge resection via video-assisted thoracoscopic surgery without requiring endotracheal intubation. We managed ventilation with a laryngeal mask airway under general anesthesia combined with a thoracic epidural block. The diseased lobe collapsed well for the surgical procedure during VATS without hypoxia, after which the resection was safely performed. CONCLUSIONS: Non-tracheal intubation anesthesia can be a potentially attractive alternative for patients undergoing contralateral pulmonary resection after pneumonectomy.

Antibacterial-Antioxidative Thiolated Gelatin/Methacrylated Silk Fibroin Hydrogels with Nitric Oxide Release Catalyzed by Metal-Polyphenol Nanoparticles for MRSA-Infected Wound Healing.

Chronic wound infection often leads to irregular tissue closure and accompanies delayed healing and economy issues. Developing an ideal wound dressing that can control the occurrence of antibacterial infections and biological responses is highly desirable. In this study, a multifunctional hybrid hydrogel (GS@EG-Cu-CA NPs) containing synthesized thiolated gelatin, methacrylated silk fibroin, and (-)-epigallocatechin gallate-copper ionic-carrageenan nanoparticles (EG-Cu-CA NPs) was engineered by a thio-ene click reaction. The metal-polyphenol EG-Cu-CA NPs were encapsulated with kappa-carrageenan to enhance its aqueous-soluble, mechanical, and bioactive properties and endowed the hydrogel dressing with fascinating antibacterial, antioxidation, and nitric oxide (NO) generation by catalyzing. The hybrid hydrogels also illustrated a favorable cytocompatibility. Benefiting from the thio-ene click reaction, the hybrid hydrogels were injected and photocured rapidly in situ to cover an irregular wound. In an SD rat full-thickness skin-wound-infected model, the methicillin-resistant Staphylococcus aureus-infected wound covered with GS@EG-Cu-CA NPs was almost completely healed after 10 days. This study presents a facile design of hydrogel dressing incorporating metal-polyphenol nanoparticles, which demonstrates a promising potential way for dealing with effective wound infection management and other complicated wound healings.

Association between hypertension and Epstein-Barr virus reactivation among the population in a high-risk area for nasopharyngeal carcinoma.

BACKGROUND: Hypertension may increase the infection risk of multiple viruses. The evidence for the association between hypertension and Epstein-Barr virus (EBV) reactivation is still largely lacking. METHODS: The study was based on the baseline information of a population-based prospective cohort from high-risk areas of nasopharyngeal carcinoma (NPC). Using two EBV reactivation classification criteria, we explored the relationship between hypertension and EBV reactivation through logistic regression models. RESULTS: We included a total of 12,159 subjects. Among them, 3,945 (32.45%) were EBV arbitrary seropositive, and 1,547 (12.72%) were EBV comprehensive seropositive. Hypertension was associated with an increased risk of EBV reactivation, with odds ratios (ORs) of 1.17 (95% CI = 1.08-1.27) for EBV arbitrary seropositive subjects and 1.16 (95% CI = 1.03-1.30) for EBV comprehensive seropositive subjects. Two types of antihypertensive drugs were associated with decreased risk of EBV reactivation: ß-adrenergic receptor-blocking agents (ß-blockers) (OR = 0.51, 95% CI = 0.42-0.61 for EBV arbitrary seropositive subjects; OR = 0.62, 95% CI = 0.47-0.81 for EBV comprehensive seropositive subjects) and angiotensin converting enzyme inhibitors (ACEIs) (OR = 0.61, 95% CI = 0.41-0.88 for EBV arbitrary seropositive subjects; OR = 0.58, 95% CI = 0.32-0.98 for EBV comprehensive seropositive subjects). CONCLUSIONS: Hypertension was associated with an increased risk of EBV reactivation in high-incidence areas of NPC. ß-blockers and ACEIs reduce this risk, and thus might be used for NPC prevention in endemic areas.

Cyanoacrylate glue foreign body after CT-guided localization of a pulmonary nodule during video-assisted thoracoscopic surgery: a case report.

BACKGROUND: A tracheal foreign body is a common airway aspiration that creates an emergency, which often causes unobserved respiratory problems and requires management. Iatrogenic tracheal foreign bodies are rarely observed, which results in tracheal obstruction. If the foreign body were removed from the tracheobronchial system, it would save lives. A similar case of a tracheal foreign body was focused on, which was caused by medical glue used during preoperative computed tomography localization of pulmonary nodules. CASE PRESENTATION: The foreign body was deposited in the right upper bronchi, accidentally discovered after anesthesia when a double-lumen tube was located by fiber bronchoscopy. Following a video-assisted thoracoscopic surgery, the foreign body was removed using a respiratory endoscopy without subsequent adverse consequences for the patient. CONCLUSIONS: There is a risk of complications from iatrogenic airway foreign bodies for preoperative localization of pulmonary nodules by injecting cyanoacrylate glue.

Development and Internal Validation of a Prediction Model for Difficult Laryngoscopy Using Ultrasound-Derived Factor in Comatose Patients.

OBJECTIVES: The distance from skin to the hyoid bone (DSHB) and skin to the anterior commissure of vocal cords (DSAC) are reliable parameters for pre-operative airway ultrasound assessment in awake patients and can be assessed in comatose patients. This study aimed to inspect its feasibility and accuracy in predicting difficult laryngoscopy for comatose patients. METHODS: A prospective cohort study included patients with a Glasgow Coma Scale (GCS) of ≤8 who underwent emergency tracheal intubation between November 2019 and August 2020. The outcome was difficult laryngoscopy and classified according to the Cormack-Lehane grading. RESULTS: A total of 151 patients were included in the study. Fifty-two (34.4%) patients were categorized as having difficult laryngoscopy. The DSHB add DSAC (hereinafter referred to as the "DSBAC") was superior to either parameter alone in the predictive performance, and the optimal cut-off value was 1.90. To optimize the predictive value, DSBAC (adjusted odds ratio [OR]: 7.76; 95% confidence interval [CI]: 2.88-20.94; P < .001), GCS (adjusted OR: 1.39; 95% CI: 3.93-26.28; P = .039), mandibular retraction (adjusted OR: 8.20; 95% CI: 1.92-35.09; P = .005) and edentulous (adjusted OR: 4.23; 95% CI: 1.40-12.80; P = .011) were included in a multivariable model and constructed a nomogram. Discrimination and calibration statistics were satisfactory, with C-index above 0.80 from both model development and internal validation. CONCLUSIONS: Ultrasound-derived factor, DSBAC, can be easily assessed and help predict difficult laryngoscopy among comatose patients. A simple nomogram including only four clinical items exhibited excellent discrimination performance and was useful when comatose patients underwent emergency tracheal intubation.

Intra- and Inter-Self-Assembly of Identical Supramolecules on Silver Surfaces.

Self-assembly of identical organometallic supramolecules into ordered superstructures is of great interest in both chemical science and nanotechnology due to its potential to generate neoteric properties through collective effects. In this work, we demonstrate that large-scale self-organization of atomically precise organometallic supramolecules can be achieved through cascaded on-surface chemical reactions, by the combination of intra- and inter-supramolecular interactions. Supramolecules with defined size and shape are first built through intramolecular reaction and intermolecular metal coordination, followed by the formation of well-ordered two-dimensional arrays with the assistance of Br atoms by -C-H···Br interactions. The mechanism of this process has been investigated from the perspectives of thermodynamics and kinetics.

Acupoint Autohemotherapy Attenuates Atopic Dermatitis Lesions by Regulating Th1/Th2 Balance in DNCB-Induced BALB/c Mice.

OBJECTIVE: To evaluate the therapeutic effects of acupoint autohemotherapy (A-AHT) on 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis (AD) in mice focusing on regulating T helper 1/T helper 2 (Th1/Th2) immune responses. METHODS: Thirty BALB/c mice were divided into 5 groups by a random number table, including normal control (NC), AD model (AD), A-AHT, sham A-AHT (sA-AHT), and acupoint injection of normal saline (A-NS) groups, 6 mice per group. Mice were challenged by DNCB for the establishment of experimental AD model. On the 8th day, except for the NC and AD groups, the mice in the other groups received management once every other day for a total of 28 days. For the A-AHT and sA-AHT groups, 0.05 mL of autologous whole blood (AWB) was injected into bilateral Zusanli (ST 36) and Quchi (LI 11) and sham-acupoints (5 mm lateral to ST 36 and LI 11), respectively. The A-NS group was administrated with 0.05 mL of normal saline by acupoint injection into ST 36 and LI 11. Dermatitis severity for dorsal skin of mice was determined using the Severity Scoring of Atopic Dermatitis (SCORAD) every week. The total immunoglobulin E (IgE), interleukin-4 (IL-4), and interferon-gamma (IFN-γ) cytokine levels in serum were examined by enzyme-linked immunosorbent assay (ELISA). Spleen Th1/Th2 expression were analyzed via flow cytometry and immunohistochemical assay was used to detect T-box expressed in T cell (T-bet) and GATA-binding protein 3 (GATA3) expressions in skin lesions of mice. RESULTS: Compared with the AD group, both A-AHT and sA-AHT reduced the SCORAD index and serum IgE level (P<0.05 or P<0.01); A-AHT, sA-AHT and A-NS down-regulated serum IL-4 level and upregulated IFN-γ/IL-4 ratio (P<0.05 or P<0.01); A-AHT regulated the Th1/Th2 shift specifically and increased the related transcription factors such as T-bet expression and T-bet/GATA3 ratio (P<0.05). CONCLUSION: A-AHT showed significant effectiveness on the AD model mice, through regulating Th1/Th2 immune responses.

Patient preferences and attitudes towards first choice medical services in Shenzhen, China: a cross-sectional study.

OBJECTIVE: This study aimed to explore the characteristics of Shenzhen residents' preferences and influencing factors regarding their first choice of medical institution at various medical levels, and to understand their attitudes towards community health services. DESIGN: Cross-sectional survey. PARTICIPANTS: A total of 1612 participants at least 18 years of age were randomly sampled with stratification among 10 districts in Shenzhen. Data were gathered through a self-designed questionnaire. The effective questionnaire response rate was 93.05%. All patients participated in the study voluntarily, provided written informed consent and were able to complete the questionnaire. MAIN OUTCOME MEASURES: We measured and compared the participants' expected and actual preferences and influencing factors regarding their first choice of medical service at various medical levels. RESULTS: More than 50% of the participants preferred municipal and district hospitals as their first choice, and 27.5% chose medical institutions according to specific circumstances. Univariate analysis indicated that age, education, income, medical insurance, housing conditions and registered permanent residence were significantly associated with the actual and expected preferred first medical institution. The main factors influencing participants' actual and expected preferred medical institution differed. With the actual preferred first medical institution as the dependent variable, education, monthly income, medical technology, convenience and providers' service attitude and medical ethics were the main factors (χ2=212.63, p<0.001), whereas with the expected preferred first medical institution as the dependent variable, occupation, Shenzhen registered permanent residence, education and medical technology were the main factors (χ2=78.101, p<0.001). CONCLUSION: The main factors influencing participants' preferred medical institution and their actual first visit differed. Patients with high education or income or registered permanent residence preferred high-level medical institutions for the first visit.

Selective ferroptosis vulnerability due to familial Alzheimer's disease presenilin mutations.

Mutations in presenilin 1 and 2 (PS1 and PS2) cause autosomal dominant familial Alzheimer's disease (FAD). Ferroptosis has been implicated as a mechanism of neurodegeneration in AD since neocortical iron burden predicts Alzheimer's disease (AD) progression. We found that loss of the presenilins dramatically sensitizes multiple cell types to ferroptosis, but not apoptosis. FAD causal mutations of presenilins similarly sensitizes cells to ferroptosis. The presenilins promote the expression of GPX4, the selenoprotein checkpoint enzyme that blocks ferroptosis by quenching the membrane propagation of lethal hydroperoxyl radicals. Presenilin γ-secretase activity cleaves Notch-1 to signal LRP8 expression, which then controls GPX4 expression by regulating the supply of selenium into the cell since LRP8 is the uptake receptor for selenoprotein P. Selenium uptake is thus disrupted by presenilin FAD mutations, suppressing GPX4 expression. Therefore, presenilin mutations may promote neurodegeneration by derepressing ferroptosis, which has implications for disease-modifying therapeutics.

Mxene Reinforced Supramolecular Hydrogels with High Strength, Stretchability, and Reliable Conductivity for Sensitive Strain Sensors.

Conductive hydrogels used as electronics have received much attention due to their great flexibility and stretchability. However, the fabrication of ideal conductive hydrogels fulfilling the excellent mechanical properties and outstanding sensitivity remains a great challenge until now. Moreover, high sensitivity and broad linearity range are pivotal for the feasibility and accuracy of hydrogel sensors. In this study, a conductive supramolecular hydrogel is engineered by directly mixing the aqueous dispersion of MXene with the precursor of N-acryloyl glycinamide (NAGA) monomer and then rapidly photo cross-linked by UV irradiation. The resultant PNAGA/MXene hydrogel-sensors exhibit high mechanical strength (4.8 MPa), great stretchability (630%), and excellent durability. The conductive hydrogel-based sensor presents excellent conductivity (17.3 S m-1 ) and a wide scope of linear dependence of sensitivity on strain (0%-125%, gauge factor = 2.05). It displays reliable detection of various motions, including repeated subtle movements and large strain. It also shows good degradation in vitro and antifouling capability. This work may provide a simple and promising platform for engineering conductive supramolecular hydrogels with integrated high performance aiming for smart wearable electronics, electronic skin, soft robots, and human-machine interfacing.

Macroporous methacrylated hyaluronic acid hydrogel with different pore sizes forin vitroandin vivoevaluation of vascularization.

Vascularization of thick hydrogel scaffolds is still a big challenge, because the submicron- or nano-sized pores seriously restrict endothelial cells adhesion, proliferation and migration. Therefore, porous hydrogels have been fabricated as a kind of promising hydrous scaffolds for enhancing vascularization during tissue repairing. In order to investigate the effects of pore size on vascularization, macroporous methacrylated hyaluronic acid (HAMA) hydrogels with different pore sizes were fabricated by a gelatin microspheres (GMS) template method. After leaching out GMS templates, uniform and highly interconnected macropores were formed in hydrogels, which provided an ideal physical microenvironment to induce human umbilical vein endothelial cells (HUVECs) migration and tissue vascularization.In vitroresults revealed that macroporous hydrogels facilitated cells proliferation and migration compared with non-macroporous hydrogels. Hydrogels with middle pore size of 200-250 µm (HAMA250 hydrogels) supported the best cell proliferation and furthest 3D migration of HUVECs. The influences of pore sizes on vascularization were then evaluated with subcutaneous embedding.In vivoresults illustrated that HAMA250 hydrogels exhibited optimum vascularization behavior. Highest number of newly formed blood vessels and expression of CD31 could be found in HAMA250 hydrogels rather than in other hydrogels. In summary, our results concluded that the best pore size for endothelial cells migration and tissue vascularization was 200-250 µm. This research provides a new insight into the engineering vascularized tissues and may find utility in designing regenerative biomaterial scaffolds.

Chemisorption-Induced Formation of Biphenylene Dimer on Ag(111).

We report an example that demonstrates the clear interdependence between surface-supported reactions and molecular-adsorption configurations. Two biphenyl-based molecules with two and four bromine substituents, i.e., 2,2'-dibromobiphenyl (DBBP) and 2,2',6,6'-tetrabromo-1,1'-biphenyl (TBBP), show completely different reaction pathways on a Ag(111) surface, leading to the selective formation of dibenzo[e,l]pyrene and biphenylene dimer, respectively. By combining low-temperature scanning tunneling microscopy, synchrotron radiation photoemission spectroscopy, and density functional theory calculations, we unravel the underlying reaction mechanism. After debromination, a biradical biphenyl can be stabilized by surface Ag adatoms, while a four-radical biphenyl undergoes spontaneous intramolecular annulation due to its extreme instability on Ag(111). Such different chemisorption-induced precursor states between DBBP and TBBP consequently lead to different reaction pathways after further annealing. In addition, using bond-resolving scanning tunneling microscopy and scanning tunneling spectroscopy, we determine with atomic precision the bond-length alternation of the biphenylene dimer product, which contains 4-, 6-, and 8-membered rings. The 4-membered ring units turn out to be radialene structures.

Potential Acupoint Prescriptions and Outcome Reporting for Acupuncture in Atopic Eczema: A Scoping Review.

BACKGROUND: Acupuncture is considered a complementary therapy for atopic eczema. The aim of this scoping review is to identify, examine, and summarize the potential acupoint prescriptions and outcome reporting regarding the clinical trials of acupuncture for eczema. METHODS: We searched different databases from inception to September 30, 2020. The data were screened and extracted to identify the potential acupuncture prescription and examine the variation in outcome reporting, outcome measurement instruments (OMIs), and measurement time points in clinical trials of acupuncture. RESULTS: A total of 116 clinical studies were included. The acupoint combination of LI11 and SP10 was used frequently. The core acupoint association networks were acupoints LI11, SP10, ST36, SP6, and LI4. For clinical trials of acupuncture, a total of 6 outcome distinct domains were identified in the 32 outcome measurements. The most frequently reported outcome was the eczema area, which was reported 97 times (83.6%, 97/116). Immune system outcomes were assessed in 15 outcome measurements, which totally reported 37 times. Adverse events were reported 51 times. TCM syndrome, which could reflect the characteristics of TCM, was reported 4 times. 29 outcomes (90.6%, 29/32) were provided definitions or OMIs. Among these outcomes, the outcome measurement times ranged from 0 to 34. CONCLUSIONS: This scoping review provides potential knowledge that should be considered as priority in future research of acupuncture for eczema.

An injectable double cross-linked hydrogel adhesive inspired by synergistic effects of mussel foot proteins for biomedical application.

Hydrogel adhesives with high tissue adhesion, biodegradability and biocompatibility are benefit for promoting surgical procedures and minimizing the pain and post-surgical complications of patients. In this paper, an injectable mussel inspired double cross-linked hydrogel adhesive composed of thiolated mussel inspired chitosan (CSDS) and tetra-succinimidyl carbonate polyethylene glycol (PEG-4S) was designed and developed. CSDS was synthesized with thiol and catechol groups inspired by the synergistic effect of mussel foot proteins (mfps). The double cross-linked hydrogel was first formed by the addition of sodium periodate (or Fe3+) and then double cross-linked with PEG-4S. The results showed that the mechanical and adhesion properties of the double cross-linked hydrogels were significantly improved by the synergistic effects of the functional groups. And the prepared hydrogels showed good cytocompatibility which evaluated by determining the viability of L929 cells and human umbilical vein endothelial cells (HUVECs). Additionally, the biodegradability and biocompatibility in vivo were further confirmed by subcutaneous implantation in mice model, and the histological analysis results identified that the prepared hydrogels were in vivo biocompatible. This work presents an injectable mussel inspired double cross-linked hydrogels that can use as a potential hydrogel adhesive for biomedical application.

Topology Selectivity in On-Surface Dehydrogenative Coupling Reaction: Dendritic Structure versus Porous Graphene Nanoribbon.

Selective control on the topology of low-dimensional covalent organic nanostructures in on-surface synthesis has been challenging. Herein, with combined scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), we report a successful topology-selective coupling reaction on the Cu(111) surface by tuning the thermal annealing procedure. The precursor employed is 1,3,5-tris(2-bromophenyl)benzene (TBPB), for which Ullmann coupling is impeded due to the intermolecular steric hindrance. Instead, its chemisorption on the Cu(111) substrate has triggered the ortho C-H bond activation and the following dehydrogenative coupling at room temperature (RT). In the slow annealing experimental procedure, the monomers have been preorganized by their self-assembly at RT, which enhances the formation of dendritic structures upon further annealing. However, the chaotic chirality of dimeric products (obtained at RT) and hindrance from dense molecular island make the fabrication of high-quality porous two-dimensional nanostructures difficult. In sharp contrast, direct deposition of TBPB molecules on a hot surface led to the formation of ordered porous graphene nanoribbons and nanoflakes, which is confirmed to be the energetically favorable reaction pathway through density functional theory-based thermodynamic calculations and control experiments. This work demonstrates that different thermal treatments could have a significant influence on the topology of covalent products in on-surface synthesis and presents an example of the negative effect of molecular self-assembly to the ordered covalent nanostructures.

Coaxial-printed small-diameter polyelectrolyte-based tubes with an electrostatic self-assembly of heparin and YIGSR peptide for antithrombogenicity and endothelialization.

Low patency ratio of small-diameter vascular grafts remains a major challenge due to the occurrence of thrombosis formation and intimal hyperplasia after transplantation. Although developing the functional coating with release of bioactive molecules on the surface of small-diameter vascular grafts are reported as an effective strategy to improve their patency ratios, it is still difficult for current functional coatings cooperating with spatiotemporal control of bioactive molecules release to mimic the sequential requirements for antithrombogenicity and endothelialization. Herein, on basis of 3D-printed polyelectrolyte-based vascular grafts, a biologically inspired release system with sequential release in spatiotemporal coordination of dual molecules through an electrostatic self-assembly was first described. A series of tubes with tunable diameters were initially fabricated by a coaxial extrusion printing method with customized nozzles, in which a polyelectrolyte ink containing of ε-polylysine and sodium alginate was used. Further, dual bioactive molecules, heparin with negative charges and Tyr-Ile-Gly-Ser-Arg (YIGSR) peptide with positive charges were layer-by-layer assembled onto the surface of these 3D-printed tubes. Due to the electrostatic interaction, the sequential release of heparin and YIGSR was demonstrated and could construct a dynamic microenvironment that was thus conducive to the antithrombogenicity and endothelialization. This study opens a new avenue to fabricate a small-diameter vascular graft with a biologically inspired release system based on electrostatic interaction, revealing a huge potential for development of small-diameter artificial vascular grafts with good patency.