T cells specific for α-myosin drive immunotherapy-related myocarditis.

Immune-related adverse events, particularly severe toxicities such as myocarditis, are major challenges to the utility of immune checkpoint inhibitors (ICIs) in anticancer therapy1. The pathogenesis of ICI-associated myocarditis (ICI-MC) is poorly understood. Pdcd1-/-Ctla4+/- mice recapitulate clinicopathological features of ICI-MC, including myocardial T cell infiltration2. Here, using single-cell RNA and T cell receptor (TCR) sequencing of cardiac immune infiltrates from Pdcd1-/-Ctla4+/- mice, we identify clonal effector CD8+ T cells as the dominant cell population. Treatment with anti-CD8-depleting, but not anti-CD4-depleting, antibodies improved the survival of Pdcd1-/-Ctla4+/- mice. Adoptive transfer of immune cells from mice with myocarditis induced fatal myocarditis in recipients, which required CD8+ T cells. The cardiac-specific protein α-myosin, which is absent from the thymus3,4, was identified as the cognate antigen source for three major histocompatibility complex class I-restricted TCRs derived from mice with fulminant myocarditis. Peripheral blood T cells from three patients with ICI-MC were expanded by α-myosin peptides. Moreover, these α-myosin-expanded T cells shared TCR clonotypes with diseased heart and skeletal muscle, which indicates that α-myosin may be a clinically important autoantigen in ICI-MC. These studies underscore the crucial role for cytotoxic CD8+ T cells, identify a candidate autoantigen in ICI-MC and yield new insights into the pathogenesis of ICI toxicity.

Protective effect of α7 nicotinic acetylcholine receptor activation on experimental colitis and its mechanism.

BACKGROUND: Inflammatory bowel disease (IBD) is a common chronic remitting disease with no satisfactory treatment. The aim of this study was to investigate the protective effect of α7 nicotinic acetylcholine receptor (α7nAChR), and to determine the underlying mechanism of its activity. METHODS: The expression and distribution of α7nAChR in the intestinal tissue of patients with ulcerative colitis and Crohn's disease were analyzed. The effects of vagal excitation on murine experimental colitis were investigated. The colitis model was induced in C57BL/6 mice by the administration of 3% dextran sulfate sodium (DSS). The therapeutic group received treatment with the α7nAChR agonist PNU-282987 by intraperitoneal injection. RESULTS: Our results showed that there was significantly increased expression of α7nAChR in colitis and Crohn's disease intestinal tissue, and its expression was mainly located in macrophages and neutrophils, which were extensively infiltrated in the disease status. Treatment with an α7nAChR agonist potently ameliorated the DSS-induced illness state, including weight loss, stool consistency, bleeding, colon shortening, and colon histological injury. α7nAChR agonist exerted anti-inflammatory effects in DSS colitis mice by suppressing the secretion of multiple types of proinflammatory factors, such as IL6, TNFα, and IL1ß, and it also inhibited the colonic infiltration of inflammatory cells by blocking the DSS-induced overactivation of the NF-κB and MAPK signaling pathways. Mechanistically, activation of α7nAChR decreased the number of infiltrated M1 macrophages in the colitis intestine and inhibited the phagocytosis ability of macrophages, which were activated in response to LPS stimulation. CONCLUSION: Thus, an α7nAChR agonist ameliorated colonic pathology and inflammation in DSS-induced colitis mice by blocking the activation of inflammatory M1 macrophages.

DNA ligase IV dificiency with elevated serum IgG levels suspected to have myelodysplastic syndrome: a case report.

BACKGROUND: Ligase IV (LIG4) dificiency is a very rare clinical syndrome with around 50 cases reported to date. This syndrome is caused by biallelic pathogenic variants in the LIG4 gene, which cause DNA damage repair disorders, mainly manifesting as severe immunodeficiency. CASE PRESENTATION: We report the case of a 15-month-old male child with pancytopenia, growth retardation, microcephaly, history of vaccine-related rubella, elevated immunoglobulin G, and decreased T- and B lymphocytes. Next-generation sequencing revealed LIG4 pathogenic genes and compound heterozygous mutations, namely the missense mutation c.833G > T (p.Arg278Leu) and deletion mutation c.1271_1275del (p.Lys424Argfs*20). CONCLUSION: This case suggests that LIG4 dificiency can manifest not only as immunodeficiency but also with increased serum IgG levels and pancytopenia, which constitutes an additional clinical phenotype. Furthermore, this case suggests that LIG4 deficiency should be considered upon differential diagnosis of myelodysplastic syndrome in children.

Polymeric Ligand-Mediated Regioselective Bonding of Plasmonic Nanoplates and Nanospheres.

Nanoparticle (NP) clusters are attractive for many applications, but controllable and regioselective assembly of clusters remains challenging. This communication reports a strategy to precisely assemble Ag nanoplates (NP-As) and Au nanospheres (NP-Bs) grafted with copolymer ligands into defined ABx clusters with controlled coordination number (x) and orientation of the NPs. The directional bonding of shaped NPs relies on the stoichiometric reaction of complementary reactive groups on copolymer ligands. The x value of NP clusters can be tuned from 1 to 4 by varying the number ratio of reactive groups on single NP-Bs to NP-As. The regioselective bonding of nanospheres to the edge or face of a central nanoplate is governed by the steric hindrance of copolymeric ligands on the nanoplate. The clusters exhibit distinctive plasmonic properties that are dependent on the bonding modes of NPs. This study paves a route to fabricating nanostructures with high precision and complexity for applications in plasmonics, catalysis, and sensing.

Intestinal tuberculosis: clinico-pathological profile and the importance of a high degree of suspicion.

OBJECTIVES: Intestinal tuberculosis (ITB) remains prevalent and a big health hazard in China. The aim of this study was to retrospectively analyse its clinico-pathological features. METHODS: Retrospective study of 85 consecutive ITB patients in two tertiary hospitals in East China. Relevant clinical, laboratory examination, radiological, endoscopic and histopathological features of ITB were recorded. RESULTS: The mean age was 37.3 ± 16.0 years; 56 patients (65.9%) were male. 67.1% had ITB secondary to pulmonary tuberculosis. The overall median length of hospital stay was 28 days and was significantly longer in patients with intestinal complications (P = 0.003) and malnutrition (P = 0.042). Abdominal pain (88.2%) and weight loss (75.3%) were the commonest symptoms. The positive rate of the purified protein derivative (PPD) test was 88.2%; of the T-spot, 85.7%. Histopathology revealed caseating granuloma in 70.6% and caseating necrosis in 24.7% of patients. The most commonly affected sites were the ileocecal valve (56, 65.9%), terminal ileum (40, 47.1%) and caecum (33, 38.8%). Only 17 (20%) patients were initially diagnosed as ITB, the other 68 patients were misdiagnosed. Six patients with caecum tuberculosis were misdiagnosed as appendicitis, four of whom had improper surgical procedures followed by post-operative intestinal fistulas; two died due to MODS. CONCLUSIONS: Diagnosis of ITB is often misdirected and delayed, which may lead to inappropriate treatment and high mortality. High diagnostic suspicion is necessary for patients with unexplained abdominal complaints. Diagnosis is not easy but could benefit coexisting pulmonary tuberculosis, T-spot, CT imaging, colonoscopy, pathological features, acid-fast bacilli and response to anti-tuberculosis therapy (ATT).

Anisotropic Self-Assembly of Hairy Inorganic Nanoparticles.

Current interest in functional assemblies of inorganic nanoparticles (NPs) stems from their collective properties and diverse applications ranging from nanomedicines to optically active metamaterials. Coating the surface of NPs with polymers allows for tailoring of the interactions between NPs to assemble them into hybrid nanocomposites with targeted architectures. This class of building blocks is termed "hairy" inorganic NPs (HINPs). Regiospecific attachment of polymers has been used to achieve directional interactions for HINP assembly. However, to date anisotropic surface functionalization of NPs still remains a challenge. This Account provides a review of the recent progress in the self-assembly of isotropically functionalized HINPs in both the condensed state and aqueous solution as well as the applications of assembled structures in such areas as biomedical imaging and therapy. It aims to provide fundamental mechanistic insights into the correlation between structural characteristics and self-assembly behaviors of HINPs, with an emphasis on HINPs made from NPs grafted with linear block copolymer (BCP) brushes. The key to the anisotropic self-assembly of these HINPs is the generation of directional interactions between HINPs by designing the surrounding medium (e.g., polymer matrix) or engineering the surface chemistry of the HINPs. First, HINPs can self-assemble into a variety of 1D, 2D, or 3D nanostructures with a nonisotropic local arrangement of NPs in films. Although a template is not always required, a polymer matrix (BCPs or supramolecules) can be used to assist the assembly of HINPs to form hybrid architectures. The interactions between brushes of neighboring HINPs or between HINPs and the polymer matrix can be modulated by varying the grafting density and length of one or multiple types of polymers on the surface of the NPs. Second, the rational design of deformable brushes of BCP or mixed homopolymer tethers on HINPs enables the anisotropic assembly of HINPs (in analogy to molecular self-assembly) into complex functional structures in selective solvents. It is evidenced that the directional interactions between BCP-grafted NPs arise from the redistribution and conformation change of the long, flexible polymer tethers, while the lateral phase separation of brushes on NP surfaces is responsible for the assembly of HINPs carrying binary immiscible homopolymers. For HINPs decorated with amphiphilic BCP brushes, their self-assembly can produce a variety of hybrid structures, such as vesicles with a monolayer of densely packed NPs in the membranes and with controlled sizes, shapes (e.g., spherical, hemispherical, disklike), and morphologies (e.g., patchy, Janus-like). This strategy allows fine-tuning of the NP organization and collective properties of HINP assemblies, thus facilitating their application in effective cancer imaging, therapy, and drug delivery. We expect that the design and assembly of such HINPs with isotropic functionalization is likely to open up new avenues for the fabrication of new functional nanocomposites and devices because of its simplicity, low cost, and ease of scale-up.

Damage Localization of Beam Bridges Using Quasi-Static Strain Influence Lines Based on the BOTDA Technique.

The diagnosis of damage in a bridge superstructure using quasi-static strain influence lines (ILs) is promising. However, it is challenging to accurately localize the damage in a bridge superstructure due to limited numbers of strain IL measurement points and inconsistencies between the loading conditions before and after damage. To address the above issues, the Brillouin optical time domain analysis (BOTDA) technique is first applied to bridge damage localization using quasi-static strain ILs, and the number of strain IL measurement points is substantially increased. Additionally, a damage localization index based on quasi-static strain ILs that is independent of differences in the loading conditions before and after damage is proposed to localize damage in the superstructure of a beam bridge. Finally, the effectiveness of the proposed method is demonstrated through both numerical analysis and measured data from a quasi-static test of a model bridge.

Laparoscopic surgery for radiation enteritis.

BACKGROUND: The aim of this study was to determine the safety and feasibility of laparoscopic surgery for radiation enteritis-induced intestinal stenosis requiring ileocecal resection. METHODS: Clinical records of radiation enteritis patients that underwent laparoscopic ileocecal resection and ileo-ascending colonic side-to-side anastomosis in a single center from January 2012-February 2014 were retrospectively analyzed. Thirty patients were identified and matched by abdominal adhesion grade, age, gender, primary malignancy distribution, previous abdominal surgery history, and body mass index to 30 patients that underwent open surgery for the same procedure from August 2009-December 2011. General information, operative findings, and short-term outcomes were compared between the two groups. RESULTS: The conversion rate of laparoscopic surgery was 23.3%. The length of skin incision in the laparoscopic group was significantly shorter than that of the open surgery group (6.8 cm versus 15.8 cm, P = 0.001). Laparoscopic surgery significantly decreased recovery time to total enteral nutrition (10.3 d versus 15.6 d, P = 0.037); however, postoperative hospital stay was not significantly different between the two groups (28.2 d versus 32.4 d, P = 0.924). Intraoperative blood loss (125 mL versus 189 mL, P = 0.000) and operation time (138 min versus 171 min, P = 0.003) were significantly improved in the laparoscopic group compared with those in the open surgery group. Laparoscopic surgery did not significantly decrease postoperative morbidity but did decrease the pleural effusion rate. CONCLUSIONS: Laparoscopic surgery is feasible for treatment of radiation enteritis-induced intestinal stenosis with a relatively low conversion rate. Laparoscopic surgery is as safe as open surgery and is superior to open surgery with decreased skin incision length, operation time, intraoperative blood loss, and postoperative recovery time to total enteral nutrition.

Model updating of complex structures using the combination of component mode synthesis and Kriging predictor.

Updating the structural model of complex structures is time-consuming due to the large size of the finite element model (FEM). Using conventional methods for these cases is computationally expensive or even impossible. A two-level method, which combined the Kriging predictor and the component mode synthesis (CMS) technique, was proposed to ensure the successful implementing of FEM updating of large-scale structures. In the first level, the CMS was applied to build a reasonable condensed FEM of complex structures. In the second level, the Kriging predictor that was deemed as a surrogate FEM in structural dynamics was generated based on the condensed FEM. Some key issues of the application of the metamodel (surrogate FEM) to FEM updating were also discussed. Finally, the effectiveness of the proposed method was demonstrated by updating the FEM of a real arch bridge with the measured modal parameters.

Donor-recipient intermicrobial interactions impact transfer of subspecies and fecal microbiota transplantation outcome.

Studies on fecal microbiota transplantation (FMT) have reported inconsistent connections between clinical outcomes and donor strain engraftment. Analyses of subspecies-level crosstalk and its influences on lineage transfer in metagenomic FMT datasets have proved challenging, as single-nucleotide polymorphisms (SNPs) are generally not linked and are often absent. Here, we utilized species genome bin (SGB), which employs co-abundance binning, to investigate subspecies-level microbiome dynamics in patients with autism spectrum disorder (ASD) who had gastrointestinal comorbidities and underwent encapsulated FMT (Chinese Clinical Trial: 2100043906). We found that interactions between donor and recipient microbes, which were overwhelmingly phylogenetically divergent, were important for subspecies transfer and positive clinical outcomes. Additionally, a donor-recipient SGB match was indicative of a high likelihood of strain transfer. Importantly, these ecodynamics were shared across FMT datasets encompassing multiple diseases. Collectively, these findings provide detailed insight into specific microbial interactions and dynamics that determine FMT success.

[Bacteriological spectrum and drug susceptibility of pus from severe intra-abdominal infected patients with abdominal trauma].

OBJECTIVE: To retrospectively analyze the bacteriological spectrum and drug susceptibility of pus flora from abdominal traumatic patients with severe intra-abdominal infection. METHODS: A total of 41 severe intra-abdominal infected patients with abdominal trauma were recruited to collect 123 abdominal pus specimens. And the results of laboratory microbiology and drug sensitivity were analyzed with the WHONET 5.4 software. RESULTS: A total of 297 strains of bacteria were isolated at (7.2 ± 2.3) strains for each patient. Gram-positive bacteria accounted for 44.1% (131/297) , Gram-negative bacteria 55.2% (164/297) and fungi 0.7% (2/297). The top five isolates were Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Enterococcus faecalis and Pseudomonas aeruginosa. Those antibiotics highly sensitive (>90%) to Escherichia coli included cefoperazone (91%), imipenem (98%); highly sensitive to Gram-positive cocci included teicoplanin (100%) and linezolid (100%). Staphylococcus aureus was 100% sensitive to vancomycin. The agents with a high susceptibility to Klebsiella pneumonia included imipenem (100%) and amikacin (79%). Ciprofloxacin (90%) had the highest sensitivity to Pseudomonas aeruginosa. CONCLUSIONS: The predominant bacteria of causing severe intra-abdominal infection of traumatic patients is Gram-negative bacteria, but the infection of Gram-positive bacteria, especially the ratio of Staphylococcus aureus infection is also comparatively high. Cefoperazone, ciprofloxacin, imipenem, vancomycin, teicoplanin and linezolid have higher antibacterial activity.

Environmental carcinogens disproportionally mutate genes implicated in neurodevelopmental disorders.

Introduction: De novo mutations contribute to a large proportion of sporadic psychiatric and developmental disorders, yet the potential role of environmental carcinogens as drivers of causal de novo mutations in neurodevelopmental disorders is poorly studied. Methods: To explore environmental mutation vulnerability of disease-associated gene sets, we analyzed publicly available whole genome sequencing datasets of mutations in human induced pluripotent stem cell clonal lines exposed to 12 classes of environmental carcinogens, and human lung cancers from individuals living in highly polluted regions. We compared observed rates of exposure-induced mutations in disease-related gene sets with the expected rates of mutations based on control genes randomly sampled from the genome using exact binomial tests. To explore the role of sequence characteristics in mutation vulnerability, we modeled the effects of sequence length, gene expression, and percent GC content on mutation rates of entire genes and gene coding sequences using multivariate Quasi-Poisson regressions. Results: We demonstrate that several mutagens, including radiation and polycyclic aromatic hydrocarbons, disproportionately mutate genes related to neurodevelopmental disorders including autism spectrum disorders, schizophrenia, and attention deficit hyperactivity disorder. Other disease genes including amyotrophic lateral sclerosis, Alzheimer's disease, congenital heart disease, orofacial clefts, and coronary artery disease were generally not mutated more than expected. Longer sequence length was more strongly associated with elevated mutations in entire genes compared with mutations in coding sequences. Increased expression was associated with decreased coding sequence mutation rate, but not with the mutability of entire genes. Increased GC content was associated with increased coding sequence mutation rates but decreased mutation rates in entire genes. Discussion: Our findings support the possibility that neurodevelopmental disorder genetic etiology is partially driven by a contribution of environment-induced germ line and somatic mutations.

A general strategy for self-assembly of nanosized building blocks on liquid/liquid interfaces.

A family of water/oil interfaces is introduced to provide effective platforms for rapid fabrication of large-area self-assembled nanofilms composed of various nanosized building blocks, including nanoparticles (NPs), nanocubes (NC), nanowires (NWs), and nanosheets, at room temperature. As a general interfacial assembly method, NWs and NPs are co-assembled at the liquid/liquid interface. The as-prepared co-assembled Ag NW and Ag NC films show high surface-enhanced Raman spectroscopy (SERS) intensity, the SERS performance being strongly dependent on the number ratio of the two kinds of nanosized building blocks. The results demonstrate that this interfacial system provides a general method for the assembly of various nanosized building blocks with different shapes and dimensionalities, and thus paves an alternative pathway for further applications of macroscopic assemblies with different functionalities.

Analysis of risk factors for early clinical recurrence of inflammatory bowel disease after fecal microbiota transplantation.

OBJECTIVE: To explore the risk factors for early clinical recurrence of inflammatory bowel disease (IBD) after fecal microbiota transplantation (FMT). METHODS: A retrospective study was conducted on 192 patients with IBD who received FMT treatment in the Colorectal Disease Specialty/Intestinal Microecology Treatment Center of the Tenth People's Hospital Affiliated to Tongji University from February 2017 to June 2020. Univariate and multivariate logistic regression models were used to analyze the risk factors for early recurrence of inflammation. Feces from all participants were collected to extract the total bacterial genomic DNA. The V6-8 regions of the bacterial 16S rDNA gene were amplified by polymerase chain reaction (PCR), the PCR products were detected by the denaturing gradient gel electrophoresis (DGGE) method, and the intestinal flora was analyzed by DNA fingerprinting. Stool samples from all patients were tested for 9 bacteria, white blood cells (WBC) and platelet (PLT) counts, as well as the erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) level. RESULTS: Of the 192 patients, 15 cases had inflammation recurrence during FMT and within one week after treatment, including 11 cases of ulcerative colitis (UC) and 4 cases of Crohn's disease (CD), with a total recurrence rate of 7.8%. High Mayo inflammatory activity score, Mayo endoscopic sub-item score (MES) =3 points, CRP>10 mg/L, anemia, albumin <30 g/L, absolute value of peripheral blood lymphocytes (PBL) <500/mm3, and intolerance to enteral full nutrition were independent risk factors for recurrence during and after FMT in UC patients (P<0.05). Albumin <30 g/L and simultaneous use of immunosuppressive agents were associated with disease recurrence during and after FMT in CD patients. WBC, PLT, and CRP were all negatively correlated with Enterococcus (EC), and ESR was positively correlated with Saccharomyces boulardii (SB) (P<0.01). CONCLUSION: The low recurrence rate of IBD after FMT indicates the safety of FMT, but this procedure should be cautiously used in patients with severe intestinal barrier dysfunction and/or severe intestinal dysfunction.

Enteral nutrition ameliorates the symptoms of Crohn's disease in mice via activating special pro-resolving mediators through innate lymphoid cells.

Crohn's disease activates the inflammatory reactions to induce intestinal disorders. Enteral nutrition (EN) could exert general immunomodulatory effects. Cecal ligation and perforation (CLP) surgery was utilized to establish Crohn's disease mice models. Survival analysis, hematoxylin-eosin staining, flow cytometry, ELISA, Western blot and liquid chromatography-tandem MS were applied. Baicalein was added to inhibit lipoxygenases. The survival rate was restored and inflammatory injury, exudate neutrophils in peritoneal lavage and serum levels of IL-6 and TNF-α were ameliorated by EN treatment as compared with CLP treatment. EN also increased ILC-3 content, 5/15-LOX level and RvD1-RvD5 in peritoneal lavage. Baicalein reversed all the detected effects of EN except ILC-3 content. EN could activate special pro-resolving mediators (SPMs) through ILCs to mitigate injuries of Crohn's disease.

3-hydroxyanthranic acid increases the sensitivity of hepatocellular carcinoma to sorafenib by decreasing tumor cell stemness.

Sorafenib is the FDA-approved first-line target drug for HCC patients. However, sorafenib only confers 3-5 months of survival benefit with <30% of HCC patients. Thus, it is necessary to develop a sensitizer for hepatocellular carcinoma (HCC) to sorafenib. Here, we report that in representative HCC cell lines (SMMC-7721 and PLC8024) that are insensitive to sorafenib, 3-HAA (50 µM) significantly enhances cell sensitivity to sorafenib to an extent that could not be explained by additive effects. In nude mice carrying HCC xenograft, tumor growth is inhibited by sorafenib (10 mg/kg/day) or 3-HAA (100 mg/kg/day) alone. When used in combination, the treatment effectively prevents the xenograft from growing. In a set of mechanistic experiments, we find enhanced AKT activation and increased proportion of CD44+CD133+ cells in sorafenib-resistant HCC cells and tissues. The proportion of CD44+CD133+ cells is reduced upon 3-HAA treatment in both cultured cells and mouse xenografts, suggesting that 3-HAA could decrease the stemness of HCC. We also detect decreased phosphorylation of AKT, a regulator of the GSK3ß/ß-catenin signaling upon 3-HAA treatment. The AKT activator SC79 activates GSK3 ß/ß-catenin signaling while the Wnt inhibitor XAV-939 abolishes 3-HAA inhibition of HCC growth in vitro and in mice. The current study demonstrates that 3-HAA sensitizes HCC cells to sorafenib by reducing tumor stemness, suggesting it is a promising molecule for HCC therapy.

Toxicity and combined effects of antibiotics and nano ZnO on a phosphorus-removing Shewanella strain in wastewater treatment.

Antibiotics and nanoparticles, which are emerging contaminants, can occur simultaneously in biological wastewater treatment systems, potentially resulting in complex interactive effects. This study investigated the effects of individual and complex zinc oxide nanoparticles (nZnO) and antibiotics (quinolone and sulfonamide), on the Shewanella strain used to remove phosphorus (PO43-), metabolic processes, as well as its complexing and toxicity mechanisms. The inhibition of PO43- removal increased from 30.7% to 100.0% with increased nZnO concentrations (half maximal effective concentration (EC50) = 1.1 mg Zn/L) by affecting poly-p and glycogen metabolites. The combined exposure to nZnO and ciprofloxacin/norfloxacin (CIP/NOR) had a significant antagonistic effect on the removal of PO43- and on the metabolism of poly-p and glycogen in phosphate-accumulating organisms (PAOs), whereas the complexing of sulfonamide and nZnO had no significant additional effect. Thus, the complexing of nanoparticles and antibiotics exhibited different toxicity effects from the antibiotic structure-based complex reactions. These results can be used to improve wastewater treatment processes and reduce risks associated with wastewater discharge.

Biologic Effect of Hydrogen Sulfide and Its Role in Traumatic Brain Injury.

Ever since endogenous hydrogen sulfide (H2S) was found in mammals in 1989, accumulated evidence has demonstrated that H2S functions as a novel neurological gasotransmitter in brain tissues and may play a key role in traumatic brain injury. It has been proved that H2S has an antioxidant, anti-inflammatory, and antiapoptosis function in the neuron system and functions as a neuroprotective factor against secondary brain injury. In addition, H2S has other biologic effects such as regulating the intracellular concentration of Ca2+, facilitating hippocampal long-term potentiation (LTP), and activating ATP-sensitive K channels. Due to the toxic nature of H2S when exceeding the physiological dose in the human body, only a small amount of H2S-related therapies was applied to clinical treatment. Therefore, it has huge therapeutic potential and has great hope for recovering patients with traumatic brain injury.

Self-limiting directional nanoparticle bonding governed by reaction stoichiometry.

Nanoparticle clusters with molecular-like configurations are an emerging class of colloidal materials. Particles decorated with attractive surface patches acting as analogs of functional groups are used to assemble colloidal molecules (CMs); however, high-yield generation of patchy nanoparticles remains a challenge. We show that for nanoparticles capped with complementary reactive polymers, a stoichiometric reaction leads to reorganization of the uniform ligand shell and self-limiting nanoparticle bonding, whereas electrostatic repulsion between colloidal bonds governs CM symmetry. This mechanism enables high-yield CM generation and their programmable organization in hierarchical nanostructures. Our work bridges the gap between covalent bonding taking place at an atomic level and colloidal bonding occurring at the length scale two orders of magnitude larger and broadens the methods for nanomaterial fabrication.