The competitive mechanism of EZH1 and EZH2 in promoting oral squamous cell carcinoma.

Enhancer of Zeste Homolog 1 (EZH1) and Enhancer of Zeste Homolog 2 (EZH2) are the key components of polycomb repressive complex 2 (PRC2); however, the roles of these proteins in oral squamous cell carcinoma (OSCC) have yet to be elucidated. In this study, we aimed to determine the respective roles of these proteins in OSCC by investigating the expression levels of EZH1 and EZH2 in OSCC tissues (N = 63) by immunohistochemistry. In addition, we used lentiviruses to construct stable OSCC cell lines that overexpressed EZH1 and EZH2. Then, we investigated these cell lines for cell viability, colony formation capacity, stemness, and epithelial-mesenchymal transition (EMT). Binding competition between EZH1 and EZH2 with PRC2 was further evaluated using Co-immunoprecipitation (Co-IP). Compared with normal tissues, the expression levels of EZH2 in OSCC tissues was up-regulated, while the expression of EZH1 was down-regulated. EZH2 enhanced cell viability, colony formation capacity, stemness, and EMT, while EZH1 did not. Furthermore, analysis indicated that EZH1 and EZH2 bound competitively to PRC2 and influenced the methylation status of H3K27. In conclusion, our findings verified that EZH1 and EZH2 play opposing roles in OSCC and that EZH1 and EZH2 compete as the key component of PRC2, thus affecting the characteristics of OSCC via the methylation of H3K27.

Cell-derived nanovesicle-mediated drug delivery to the brain: Principles and strategies for vesicle engineering.

Developing strategies toward safe and effective drug delivery into the central nervous system (CNS) with improved targeting abilities and reduced off-target effects is crucial. CNS-targeted drug carriers made of synthetic molecules raise concerns about their biodegradation, clearance, immune responses, and neurotoxicity. Cell-derived nanovesicles (CDNs) have recently been applied in CNS-targeted drug delivery, because of their intrinsic stability, biocompatibility, inherent homing capability, and the ability to penetrate through biological barriers, including the blood-brain barrier. Among these CDNs, extracellular vesicles and exosomes are the most studied because their surface can be engineered and modified to cater to brain targeting. In this review, we focus on the application of CDNs in brain-targeted drug delivery to treat neurological diseases. We cover recently developed methods of exosome derivation and engineering, including exosome-like particles, hybrid exosomes, exosome-associated adeno-associated viruses, and envelope protein nanocages. Finally, we discuss the limitations and project the future development of the CDN-based brain-targeted delivery systems, and conclude that engineered CDNs hold great potential in the treatment of neurological diseases.

Exosome for mRNA delivery: strategies and therapeutic applications.

Messenger RNA (mRNA) has emerged as a promising therapeutic molecule with numerous clinical applications in treating central nervous system disorders, tumors, COVID-19, and other diseases. mRNA therapies must be encapsulated into safe, stable, and effective delivery vehicles to preserve the cargo from degradation and prevent immunogenicity. Exosomes have gained growing attention in mRNA delivery because of their good biocompatibility, low immunogenicity, small size, unique capacity to traverse physiological barriers, and cell-specific tropism. Moreover, these exosomes can be engineered to utilize the natural carriers to target specific cells or tissues. This targeted approach will enhance the efficacy and reduce the side effects of mRNAs. However, difficulties such as a lack of consistent and reliable methods for exosome purification and the efficient encapsulation of large mRNAs into exosomes must be addressed. This article outlines current breakthroughs in cell-derived vesicle-mediated mRNA delivery and its biomedical applications.

Brain-derived extracellular vesicles: Potential diagnostic biomarkers for central nervous system diseases.

Extracellular vesicles (EVs) are membrane-enclosed nanovesicles secreted by cells into the extracellular space and contain functional biomolecules, e.g. signaling receptors, bioactive lipids, nucleic acids, and proteins, which can serve as biomarkers. Neurons and glial cells secrete EVs, contributing to various physiological and pathological aspects of brain diseases. EVs confer their role in the bidirectional crosstalk between the central nervous system (CNS) and the periphery owing to their distinctive ability to cross the unique blood-brain barrier (BBB). Thus, EVs in the blood, cerebrospinal fluid (CSF), and urine can be intriguing biomarkers, enabling the minimally invasive diagnosis of CNS diseases. Although there has been an enormous interest in evaluating EVs as promising biomarkers, the lack of ultra-sensitive approaches for isolating and detecting brain-derived EVs (BDEVs) has hindered the development of efficient biomarkers. This review presents the recent salient findings of exosomal biomarkers, focusing on brain disorders. We summarize highly sensitive sensors for EV detection and state-of-the-art methods for single EV detection. Finally, the prospect of developing advanced EV analysis approaches for the non-invasive diagnosis of brain diseases is presented.

Silver-Enabled Cycloaddition of Bicyclobutanes with Isocyanides for the Synthesis of Polysubstituted 3-Azabicyclo[3.1.1]heptanes.

Synthesis of bicyclic scaffolds has emerged as an important research topic in modern drug development because they can serve as saturated bioisosters to enhance the physicochemical properties and metabolic profiles of drug candidates. Here we report a remarkably simple silver-enabled strategy to access polysubstituted 3-azabicyclo[3.1.1]heptanes in a single operation from readily accessible bicyclobutanes (BCBs) and isocyanides. The process is proposed to involve a formal (3+3)/(3+2)/retro-(3+2) cycloaddition sequence. This novel protocol allows for rapid generation of molecular complexity from simple starting materials, and the products can be easily derivatized, further enriching the BCB cycloaddition chemistry and the growing set of valuable sp3-rich bicyclic building blocks.

Electrochemical Oxidation Induced Selective C-C Bond Cleavage.

Selective C-C bond cleavage under mild conditions can serve as a valuable tool for organic syntheses and macromolecular degradation. However, the conventional chemical methods have largely involved the use of noble transition-metal catalysts as well as the stoichiometric and perhaps environmentally unfriendly oxidants, compromising the overall sustainable nature of C-C transformation chemistry. In this regard, electrochemical C-C bond cleavage has been identified as a sustainable and scalable strategy that employs electricity to replace byproduct-generating chemical reagents. To date, the progress made in this area has mainly relied on Kolbe electrolysis and related processes. Encouragingly, more and more examples of the cleavage of C-C bonds via other maneuvers have recently been developed. This review provides an overview on the most recent and significant developments in electrochemically oxidative selective C-C bond cleavage, with an emphasis on both synthetic outcomes and reaction mechanisms, and it showcases the innate advantages and exciting potentials of electrochemical synthesis.

Targeted therapy using engineered extracellular vesicles: principles and strategies for membrane modification.

Extracellular vesicles (EVs) are 30-150 nm membrane-bound vesicles naturally secreted by cells and play important roles in intercellular communication by delivering regulatory molecules such as proteins, lipids, nucleic acids and metabolites to recipient cells. As natural nano-carriers, EVs possess desirable properties such as high biocompatibility, biological barrier permeability, low toxicity, and low immunogenicity, making them potential therapeutic delivery vehicles. EVs derived from specific cells have inherent targeting capacity towards specific cell types, which is yet not satisfactory enough for targeted therapy development and needs to be improved. Surface modifications endow EVs with targeting abilities, significantly improving their therapeutic efficiency. Herein, we first briefly introduce the biogenesis, composition, uptake and function of EVs, and review the cargo loading approaches for EVs. Then, we summarize the recent advances in surface engineering strategies of EVs, focusing on the applications of engineered EVs for targeted therapy. Altogether, EVs hold great promise for targeted delivery of various cargos, and targeted modifications show promising effects on multiple diseases.

Edible exosome-like nanoparticles from portulaca oleracea L mitigate DSS-induced colitis via facilitating double-positive CD4+CD8+T cells expansion.

Plant-derived exosome-like nanoparticles (PDENs) have been paid great attention in the treatment of ulcerative colitis (UC). As a proof of concept, we isolated and identified Portulaca oleracea L-derived exosome-like nanoparticles (PELNs) from edible Portulaca oleracea L, which exhibited desirable nano-size (~ 160 nm) and a negative zeta potential value (-31.4 mV). Oral administration of PELNs effectively suppressed the expressions of pro-inflammatory cytokines (TNF-α, IL-6, IL-12, and IL-1ß) and myeloperoxidase (MPO), increased levels of the anti-inflammatory cytokine (IL-10), and alleviated acute colitis in dextran sulfate sodium (DSS)-induced C57 mice and IL-10-/- mice. Notably, PELNs exhibited excellent stability and safety within the gastrointestinal tract and displayed specific targeting to inflamed sites in the colons of mice. Mechanistically, oral administration of PELNs played a crucial role in maintaining the diversity and balance of gut microbiota. Furthermore, PELNs treatment enhanced Lactobacillus reuteri growth and elevated indole derivative levels, which might activate the aryl-hydrocarbon receptor (AhR) in conventional CD4+ T cells. This activation downregulated Zbtb7b expression, leading to the reprogramming of conventional CD4+ T cells into double-positive CD4+CD8+T cells (DP CD4+CD8+ T cells). In conclusion, our findings highlighted the potential of orally administered PELNs as a novel, natural, and colon-targeted agent, offering a promising therapeutic approach for managing UC. Schematic illustration of therapeutic effects of oral Portulaca oleracea L -derived natural exosome-like nanoparticles (PELNs) on UC. PELNs treatment enhanced Lactobacillus reuteri growth and elevated indole derivative levels, which activate the aryl-hydrocarbon receptor (AhR) in conventional CD4+ T cells leading to downregulate the expression of Zbtb7b, reprogram of conventional CD4+ T cells into double-positive CD4+CD8+T cells (DP CD4+CD8+ T cells), and decrease the levels of pro-inflammatory cytokines.

Intratumoral platelet microthrombi in oral squamous cell carcinoma: A marker of lymph node metastasis.

OBJECTIVE: A hypercoagulable state exists in patients with oral squamous cell carcinoma (OSCC), but the role of platelets in the tumour microenvironment has not been explored. This study revealed the status of intratumoral plateletmicrothrombi (PLT-MT) and their clinicopathological relevance and predictive value in OSCC. STUDY DESIGN: This study retrospectively evaluated 106 OSCC patients. Tumour and tumour-adjacent tissue specimens were used to stain PLT-MT. Clinicopathological information, patient follow-ups and outcomes and preoperative coagulation and inflammatory hematologic indicators were collected, and their correlation with PLT-MT was analysed. RESULTS: Intratumoral PLT-MT was present in 35 of 106 patients with OSCC who had higher preoperative D-dimer, CRP, FIB and PT levels and lower TT levels. PLT-MT was an independent correlative factor of lymph node metastasis and suggested worse OS in N0 patients. CONCLUSIONS: Intratumoral PLT-MT was found in OSCC and was correlated with a hypercoagulable inflammatory state. PLT-MT was an independent marker of lymph node metastasis and showed potential in prognosis prediction.

Bisphenol F induced hyperglycemia via activation of oxidative stress-responsive miR-200 family in the pancreas.

Bisphenol F (BPF), BPS and BPAF are gaining popularity as main substitutes to BPA, but there is no clear evidence that these compounds disrupt glycemic homeostasis in the same way. In this study, four bisphenols were administered to C57BL/6 J mice, and showed that the serum insulin was elevated in the BPA and BPS exposed mice, whereas BPF exposed mice exhibited lower serum insulin and higher blood glucose. BPF decreased oxidized glutathione/reduced glutathione ratio (GSSG/GSH) and N6-methyladenosine (m6A) levels, which was responsible for pancreatic apoptosis in mice. Additionally, the downregulation of Nrf2 and the aberrant regulation of the p53-lncRNA H19 signaling pathway further increased miR-200 family in the BPF-exposed pancreas. The miR-200 family directly suppressed Mettl14 and Xiap by targeting their 3' UTR, leading to islet apoptosis. Antioxidant treatment not only elevated m6A levels and insulin contents but also suppressed the miR-200 family in the pancreas, ultimately improving BPF-induced hyperglycemia. Taken together, miR-200 family could serve as a potential oxidative stress-responsive regulator in the pancreas. And moreover, we demonstrated a novel toxicological mechanism in that BPF disrupted the Keap1-Nrf2 redox system to upregulate miR-141/200b/c which controlled pancreatic insulin production and apoptosis via Mettl14 and Xiap, respectively. As the major surrogates of BPA in various applications, BPF was also diabetogenic, which warrants attention in future research.

Risk of second primary cancer in patients with head and neck squamous cell carcinoma: a systemic review and meta-analysis.

OBJECTIVES: Second primary cancer is a common event in patients with head and neck squamous cell carcinoma. However, the incidence and relevant factors vary by studies. We conducted a systematic review and meta-analysis of observational studies to estimate the incidence and relevant risk factors. MATERIALS AND METHODS: PubMed and Web of Science were searched for studies published between January 2000 and December 2020 that reported the incidence of SPC in HNSCC patients. Per 1000-person-year incidence and odds ratios were used to estimate the incidence and potential risk factors. Due to the high heterogeneity, random-effects models were used to estimate the incidence and 95% confidence interval. RESULTS: Seven thousand seven hundred thirteen articles were identified from the databases, in which 60 studies were included in this meta-analysis. The pooled incidence of the total, synchronous, and metachronous SPC in patients with HNSCC were 29.116 per 1000-person-year, 6.960 per 1000-person-year, and 26.025 per 1000-person-year, respectively. The head and neck region was the most common area where SPC occurred, followed by the lung (7.472 per 1000-person-year) and upper digestive tract (2.696 per 1000-person-year). Smoking, alcohol consumption, betel quid chewing, primary cancer of T1-2, and N0 were risk factors, while HPV infection (OR 0.47, 95% CI 0.30-0.72) was the protective factor. CONCLUSIONS: SPC is frequently observed in HNSCC patients and had great impact on the prognosis. The findings could promote a more individualized follow-up strategy for SPC in HNSCC patients. CLINICAL RELEVANCE: This systemic review and meta-analysis provide sufficient evidence for the establishment of the follow-up strategy for head and neck squamous cancer patients.

The contralateral-based submental artery island flap: feasibility and oncological safety in oral cancer-related defect reconstruction.

OBJECTIVES: Oncologic risk is a serious concern of submental artery island flaps. Here, we introduce the contralateral-based submental artery island flap (C-SAIF) and demonstrate its feasibility and long-term oncological safety in reconstructing oral cancer-related defects. METHODS: An anatomical study was performed concentrating on the pedicle length in seven cadavers. Then, a retrospective study was carried out on C-SAIF patients operated on by a single team. The standard surgical technique of C-SAIF was conducted. Outcomes including operative time, length of hospital stay, volume of intraoperative blood loss, and scores of the Multidisciplinary Salivary Gland Society (MSGS) questionnaire were compared with a similar cohort reconstructed with anterolateral thigh free flap (ALTF). In addition, oncological outcomes were evaluated by the 5-year cumulative survival rate between C-SAIF and ALTF patients. RESULTS: The pedicle length of C-SAIF was sufficient for the flap to be extended to the contralateral oral cavity. Fifty-two patients were included in the retrospective study, and nineteen of them underwent reconstruction with C-SAIF. The operative time of C-SAIF was shorter (p = 0.003), and the intraoperative blood loss was less (p = 0.004) than that of ALTF. There was no difference in MSGS scores. The results of survival analysis revealed comparable survival curves for the two groups in terms of overall survival, disease-specific survival, and disease-free survival. CONCLUSION: C-SAIF is a feasible and reliable flap for reconstructing oral cancer-related defects. Moreover, it is an effective island flap to preserve the perforator and pedicle without compromising oncological safety.

Speech disorders in patients with Tongue squamous cell carcinoma: A longitudinal observational study based on a questionnaire and acoustic analysis.

BACKGROUND: Speech disorders are common dysfunctions in patients with tongue squamous cell carcinoma (TSCC) that can diminish their quality of life. There are few studies with multidimensional and longitudinal assessments of speech function in TSCC patients. METHODS: This longitudinal observational study was conducted at the Hospital of Stomatology, Sun Yat-sen University, China, from January 2018 to March 2021. A cohort of 92 patients (53 males, age range: 24-77 years) diagnosed with TSCC participated in this study. Speech function was assessed from preoperatively to one year postoperatively using the Speech Handicap Index questionnaire and acoustic parameters. The risk factors for postoperative speech disorder were analyzed by a linear mixed-effects model. A t test or Mann‒Whitney U test was applied to analyze the differences in acoustic parameters under the influence of risk factors to determine the pathophysiological mechanisms of speech disorders in patients with TSCC. RESULTS: The incidence of preoperative speech disorders was 58.7%, which increased up to 91.4% after surgery. Higher T stage (P＜0.001) and larger range of tongue resection (P = 0.002) were risk factors for postoperative speech disorders. Among the acoustic parameters, F2/i/decreased remarkably with higher T stage (P = 0.021) and larger range of tongue resection (P = 0.009), indicating restricted tongue movement in the anterior-posterior direction. The acoustic parameters analysis during the follow-up period showed that F1 and F2 were not significantly different of the patients with subtotal or total glossectomy over time. CONCLUSIONS: Speech disorders in TSCC patients is common and persistent. Less residual tongue volume led to worse speech-related QoL, indicating that surgically restoring the length of the tongue and strengthening tongue extension postoperatively may be important.

Catalytic Formal [2π+2σ] Cycloaddition of Aldehydes with Bicyclobutanes: Expedient Access to Polysubstituted 2-Oxabicyclo[2.1.1]hexanes.

Synthesis of bicyclic scaffolds has attracted tremendous attention because they are playing an important role as saturated bioisosteres of benzenoids in modern drug discovery. Here, we report a BF3 -catalyzed [2π+2σ] cycloaddition of aldehydes with bicyclo[1.1.0]butanes (BCBs) to access polysubstituted 2-oxabicyclo[2.1.1]hexanes. A new kind of BCB containing an acyl pyrazole group was invented, which not only significantly facilitates the reactions, but can also serve as a handle for diverse downstream transformations. Furthermore, aryl and vinyl epoxides can also be utilized as substrates which undergo cycloaddition with BCBs after in situ rearrangement to aldehydes. We anticipate that our results will promote access to challenging sp3 -rich bicyclic frameworks and the exploration of BCB-based cycloaddition chemistry.

Synthesis of Polysubstituted 2-Oxabicyclo[2.1.1]hexanes via Visible-Light-Induced Energy Transfer.

Synthesis of bicyclic scaffolds has attracted growing interest because they are of high importance in modern pharmaceutical development. Here we report a strategy to access polysubstituted 2-oxabicyclo[2.1.1]hexanes in a single operation from readily accessible benzoylformate esters and bicyclo[1.1.0]butanes via visible-light-induced triplet energy transfer catalysis. The process is proposed to involve a formal [2π + 2σ] photocycloaddition/backbone C-H abstraction/aryl group migration sequence. A diverse range of (hetero)aryl groups successfully underwent migration to the backbone (C2) position to provide previously inaccessible bicyclic molecules, and the ester group of the product can serve as a handle for downstream manipulation, thus offering opportunities to rapidly build up molecular complexity and access new sp3-rich chemical space.

Site-Selective Lysine Acetylation of Human Immunoglobulin G for Immunoliposomes and Bispecific Antibody Complexes.

Site-selective acetylation of a single lysine residue in a protein that reaches a lysine acetyltransferase's accuracy, precision, and reliability is challenging. Here, we report a peptide-guided, proximity-driven group transfer reaction that acetylates a single lysine residue, Lys 248, of the fragment crystallizable region (Fc region) in the heavy chain of the human Immunoglobulin G (IgG). An Fc-interacting peptide bound with the Fc domain and positioned a phenolic ester close to Lys 248, which induced a nucleophilic reaction and resulted in the transfer of an acetyl group to Lys 248. The acetylation reaction proceeded to a decent yield under the physiological condition without the need for deglycosylation, unnatural amino acids, or catalysts. Along with acetylation, functional moieties such as azide, alkyne, fluorescent molecules, or biotin could also be site-selectively installed on Lys 248, allowing IgG's further derivatization. We then synthesized an antibody-lipid conjugate and constructed antibody-conjugated liposomes (immunoliposomes), targeting HER2-positive (HER2+) cancer cells. We also built a bispecific antibody complex (bsAbC) covalently linking an anti-HER2 antibody and an anti-CD3 antibody. The bsAbC showed in vitro effector-cell-mediated cytotoxicity at nanomolar concentrations. Compared with bispecific antibodies (bsAbs), bsAbCs are constructed based on native IgGs and contain two antigen-binding sites to each antigen, twice that of bsAbs. Altogether, this work reports a method of site-selective acetylation of native antibodies, highlights a facile way of site-selective IgG functionalization, and underscores the potential of bsAbCs in cancer immunotherapy.

Modification of mesenchymal stem cells for cartilage-targeted therapy.

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the destruction of the articular cartilage, sclerosis of the subchondral bone, and joint dysfunction. Its pathogenesis is attributed to direct damage and mechanical destruction of joint tissues. Mesenchymal stem cells (MSCs), suggested as a potential strategy for the treatment of OA, have shown therapeutic effects on OA. However, the specific fate of MSCs after intraarticular injection, including cell attachment, proliferation, differentiation, and death, is still unclear, and there is no guarantee that stem cells can be retained in the cartilage tissue to enact repair. Direct homing of MSCs is an important determinant of the efficacy of MSC-based cartilage repair. Recent studies have revealed that the unique homing capacity of MSCs and targeted modification can improve their ability to promote tissue regeneration. Here, we comprehensively review the homing effect of stem cells in joints and highlight progress toward the targeted modification of MSCs. In the future, developments of this targeting system that accelerate tissue regeneration will benefit targeted tissue repair.

Epigenetic DNA methylation of Zbtb7b regulates the population of double-positive CD4+CD8+ T cells in ulcerative colitis.

BACKGROUND AND AIMS: Ulcerative colitis (UC) is a heterogeneous disorder with complex pathogenesis. Therefore, in the present study, we aimed to assess genome-wide DNA methylation changes associated explicitly with the pathogenesis of UC. METHODS: DNA methylation changes were identified by comparing UC tissues with healthy controls (HCs) from the GEO databases. The candidate genes were obtained and verified in clinical samples. Moreover, the underlying molecular mechanism related to Zbtb7b in the pathogenesis of UC was explored using the dextran sodium sulfate (DSS)-induced colitis model. RESULTS: Bioinformatic analysis from GEO databases confirmed that Zbtb7b, known as Th-inducing POZ-Kruppel factor (ThPOK), was demethylated in UC tissues. Then, we demonstrated that Zbtb7b was in a hypo-methylation pattern through the DSS-induced colitis model (P = 0.0357), whereas the expression of Zbtb7b at the mRNA and protein levels was significantly up-regulated in the inflamed colonic tissues of UC patients (qRT-PCR, WB, IHC: P < 0.0001, P = 0.0079, P < 0.0001) and DSS-induced colitis model (qRT-PCR, WB, IHC: P < 0.0001, P = 0.0045, P = 0.0004). Moreover, the expression of Zbtb7b was positively associated with the degree of UC activity. Mechanically, over-expression of Zbtb7b might activate the maturation of CD4+T cells (FCM, IF: P = 0.0240, P = 0.0003) and repress the differentiation of double-positive CD4+CD8+T (DP CD4+CD8+T) cells (FCM, IF: P = 0.0247, P = 0.0118), contributing to the production of inflammatory cytokines, such as TNF-α (P = 0.0005, P = 0.0005), IL-17 (P = 0.0014, P = 0.0381), and IFN-γ (P = 0.0016, P = 0.0042), in the serum and colonic tissue of DSS-induced colitis model. CONCLUSIONS: Epigenetic DNA hypo-methylation of Zbtb7b activated the maturation of CD4+T cells and repressed the differentiation of DP CD4+CD8+ T cells, resulting in the production of inflammatory cytokines and colonic inflammation in UC. Therefore, Zbtb7b might be a diagnostic and therapeutic biomarker for UC, and hypo-methylation might affect the biological function of Zbtb7b.

Nanolayer-Constructed TiO(OH)2 Microstructures for the Efficiently Selective Removal of Cationic Dyes via an Electrostatic Interaction and Adsorption Mechanism.

Efficient removal of organic dyes from contaminated water has become a great challenge and urgent work due to increasingly serious environmental problems. Here, we have for the first time prepared nanolayer-constructed TiO(OH)2 microstructures which can present negative charge by deprotonation of the hydroxyl group to efficiently and selectively remove cationic dyes from aqueous solution through electrostatic interaction and an attraction mechanism. The nanolayer-constructed TiO(OH)2 microstructures achieve a high adsorption capacity of 257 mg g-1 for methylene blue (MB). The adsorption kinetics, thermodynamics, and isotherms of MB over the TiO(OH)2 microstructures have been studied systemically. The experimental measurements and corresponding analyses demonstrate that the adsorption process of MB on TiO(OH)2 microstructures follows a kinetic model of pseudo-second-order adsorption, agrees well with the Langmuir isotherm mode, and is a spontaneous and exothermic physisorption. Fourier transform infrared (FT-IR) spectra confirm that the prepared TiO(OH)2 microstructures possess hydroxyl group which can deprotonate to present negative charge in solution. Further experimental studies evidently demonstrate that the TiO(OH)2 microstructures also can remove other cationic dyes with positive charge such as basic yellow 1, basic green 4, and crystal violet but cannot adsorb anionic dye of methyl orange (MO) with negative charge in aqueous solution. The measurements for FT-IR spectra and the adsorption of cationic and anionic dyes evidently reveal that the adsorption of cationic dyes over the TiO(OH)2 microstructures is achieved by the electrostatic interaction and attraction between TiO(OH)2 and the dye. This work opens a strategy for the design of new absorbents to efficiently remove organic dyes from aqueous solution through an electrostatic attraction-driven adsorption process.

IrIII/NiII-Metallaphotoredox-Catalyzed Enantioselective Decarboxylative Arylation of α-Amino Acids: Theoretical Insight of Enantio-Determining Outer-Sphere Reductive Elimination.

The IrIII/NiII-metallaphotoredox-catalyzed enantioselective decarboxylative arylation of α-amino acids has been systematically investigated using density functional theory calculations. The combination of oxidative quenching (IrIII-*IrIII-IrIV-IrIII) or reductive quenching (IrIII-*IrIII-IrII-IrIII) cycle with the nickel catalytic cycle (NiII-NiI-NiIII-NiII) is possible. The favorable reaction mechanism consists of three major processes: single-electron transfer, oxidative addition, and stepwise outer-sphere reductive elimination. The rate-determining step is the oxidative addition. Unexpectedly, the enantio-determining C-C bond formation occurs via an ion-pair intermediate involved in the stepwise outer-sphere reductive elimination process, which is unusual in the IrIII/NiII-metallaphotoredox catalysis. Furthermore, computational results reveal that the high enantioselectivity of this reaction is mainly dependent on the steric effect of substituents on substrates. This theoretical study provides useful knowledge for deep insights into the activity and selectivity of visible-light-mediated enantioselective metallaphotoredox dual catalysis at the molecular and atomic levels and benefits the development of asymmetric synthesis.