H-and J-aggregation of conjugated small molecules in organic solar cells

As H-and J-aggregation receive more and more attention in the research of organic solar cells(OSCs),especially in small molecular systems,deep understanding of aggregation behavior is needed to guide the design of conjugated small molecular structure and the fabrication process of OSC device.For this end,this review is written.Here,the review firstly introduced the basic information about H-and J-aggregation of conjugated small molecules in OSCs.Then,the characteristics of H-and J-aggregation and the methods to identify them were summarized.Next,it reviewed the research progress of H-and J-aggregation of conjugated small molecules in OSCs,including the factors influencing H-and J-aggregation in thin film and the effects of H-and J-aggregation on OPV performance.

Antiviral effects of natural small molecules on aquatic rhabdovirus by interfering with early viral replication

Spring viremia of carp virus(SVCV)is globally widespread and poses a serious threat to aquatic ecology and aquaculture due to its broad host range.To develop effective agents to control SVCV infection,we selected 16 naturally active small molecules to assess their anti-SVCV activity.Notably,dihydroartemisinin(DHA)(100μmol/L)and(S,S)-(+)-tetrandrine(TET)(16μmol/L)exhibited high antiviral effects in epithelioma papulosum cyprinid(EPC)cells,with inhibitory rates of 70.11%and 73.54%,respectively.The possible antiviral mechanisms were determined as follows:1.Preincubation with DHA and TET decreased viral particle infectivity in fish cells,suggesting that horizontal transmission of SVCV in the aquatic environment was disrupted;2.Although neither had an effect on viral adhesion,TET(but not DHA)interfered with SVCV entry into host cells(>80%),suggesting that TET may have an antiviral function in early viral replication.For in vivo study,both agents enhanced the survival rate of SVCV-infected zebrafish by 53.3%,significantly decreased viral load,and modulated the expression of antiviralrelated genes,indicating that DHA and TET may stimulate the host innate immune response to prevent viral infection.Overall,our findings indicated that DHA and TET had positive effects on suppressing SVCV infection by affecting early-stage viral replication,thus holding great potential as immunostimulants to reduce the risk of aquatic rhabdovirus disease outbreaks.

Direct conversion of human fibroblasts into dopaminergic neuron-like cells using small molecules and protein factors

Background:Generation of neurons is essential in cell replacement therapy for neurodegenerative disorders like Parkinson’s disease.Several studies have reported the generation of dopaminergic(DA)neurons from mouse and human fibroblasts by ectopic expression of transcription factors,in which genetic manipulation is associated with potential risks.Methods:The small molecules and protein factors were selected based on their function to directly induce human fetal lung IMR-90 fibroblasts into DA neuron-like cells.Microscopical,immunocytochemical,and RT-qPCR analyses were used to characterize the morphology,phenotype,and gene expression features of the induced cells.The wholecell patch-clamp recordings were exploited to measure the electrophysiological properties.Results:Human IMR-90 fibroblasts were rapidly converted into DA neuron-like cells after the chemical induction using small molecules and protein factors,with a yield of approximately 95%positive TUJ1-positive cells.The induced DA neuron-like cells were immunopositive for pan-neuronal markers MAP2,NEUN,and Synapsin 1 and DA markers TH,DDC,DAT,and NURR1.The chemical induction process did not involve a neural progenitor/stem cell intermediate stage.The induced neurons could fire single action potentials,which reflected partially the electrophysiological properties of neurons.Conclusions:We developed a chemical cocktail of small molecules and protein factors to convert human fibroblasts into DA neuron-like cells without passing through a neural progenitor/stem cell intermediate stage.The induced DA neuron-like cells from human fibroblasts might provide a cellular source for cell-based therapy of Parkinson’s disease in the future.

New matrix of MALDI-TOF MS for analysis of small molecules

New matrix, metal-phthalocyanine （MPc）, of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS） was used for analysis of small molecules （usually 〈500 Da）. By using MPcs as matrices, small molecular samples were moved to high mass-to-charge region where there was no interference caused by the traditional matrices. The mass of the target analvte was obtained by simple calculation.

Role of the combination of biologics and/or small molecules in the treatment of patients with inflammatory bowel disease

Inflammatory bowel disease(IBD)is a group of chronic diseases that includes ulcerative colitis,Crohn’s disease,and indeterminate colitis.Patients with IBD require prolonged treatment and high utilization of healthcare resources for proper management.The treatment of patients with IBD is focused on achieving therapeutic goals including clinical,biochemical,and endoscopic variables that result in improvement of the quality of life and prevention of disability.Advanced IBD treatment includes tumor necrosis factor inhibitors,integrin antagonist,antagonist of the p40 subunit of interleukin 12/23,and small molecule drugs.However,despite the multiple treatments available,about 40%of patients are refractory to therapy and present with persistent symptoms that have a great impact on their quality of life,with hospitalization and surgery being necessary in many cases.Dual therapy,a strategy sometimes applicable to refractory IBD patients,includes the combination of two biologics or a biologic in combination with a small molecule drug.There are two distinct scenarios in IBD patients in which this approach can be used:(1)Refractory active luminal disease without extraintestinal manifestations;and(2)patients with IBD in remission,but with active extraintestinal manifestations or immune-mediated inflammatory diseases.This review provides a summary of the results(clinical response and remission)of different combinations of advanced drugs in patients with IBD,both in adults and in the pediatric population.In addition,the safety profile of different combinations of dual therapy is analyzed.The use of newer combinations,including recently approved treatments,the application of new biomarkers and artificial intelligence,and clinical trials to establish effectiveness during long-term followup,are needed to establish new strategies for the use of advanced treatments in patients with refractory IBD.

Transformation of peptides to small molecules in medicinal chemistry:Challenges and opportunities

Peptides are native binders involved in numerous physiological life procedures,such as cellular signaling,and serve as ready-made regulators of biochemical processes.Meanwhile,small molecules compose many drugs owing to their outstanding advantages of physiochemical properties and synthetic convenience.A novel field of research is converting peptides into small molecules,providing a convenient portable solution for drug design or peptidomic research.Endowing properties of peptides onto small molecules can evolutionarily combine the advantages of both moieties and improve the biological druggability of molecules.Herein,we present eight representative recent cases in this conversion and elaborate on the transformation process of each case.We discuss the innovative technological methods and research approaches involved,and analyze the applicability conditions of the approaches and methods in each case,guiding further modifications of peptides to small molecules.Finally,based on the aforementioned cases,we summarize a general procedure for peptide-to-small molecule modifications,listing the technological methods available for each transformation step and providing our insights on the applicable scenarios for these methods.This review aims to present the progress of peptide-to-small molecule modifications and propose our thoughts and perspectives for future research in this field.

Electrochemical conversion of organic compounds and inorganic small molecules

Electrochemical synthesis presents a facile and sustainable strategy to produce valuable molecules.This review summarizes the most recent advances in electrosynthesizing value-added compounds with inorganic small molecules.While“small molecules”refers to a broad spectrum of chemicals,we mainly focus on the electrochemical conversion of CO_(2),H_(2)O/D_(2)O,NH_(3)and SO_(2)until March 2024.This review intends to compare the results and display general trends throughout the field,with an emphasis on the substrate scope and mechanical aspect.Furthermore,we propose several techniques and protocols that can enable a more fundamental understanding of the electrochemical reaction involving inorganic small molecules and help drive this methodology toward commercialization.

Small molecules targeting protein-protein interactions for cancer therapy

Protein-protein interactions(PPIs)are fundamental to many biological processes that play an important role in the occurrence and development of a variety of diseases.Targeting the interaction between tumour-related proteins with emerging small molecule drugs has become an attractive approach for treatment of human diseases,especially tumours.Encouragingly,selective PPI-based therapeutic agents have been rapidly advancing over the past decade,providing promising perspectives for novel therapies for patients with cancer.In this review we comprehensively clarify the discovery and development of small molecule modulators of PPIs from multiple aspects,focusing on PPIs in disease,drug design and discovery strategies,structure-activity relationships,inherent dilemmas,and future directions.

Functional customization of two-dimensional materials for photocatalytic activation and conversion of inert small molecules in the air

Air has the advantage of abundance and easy availability,so it is suitable to be used as a synthetic raw material and energy source.However,the triggering of inert small molecules in the air,like O_(2),N2,and CO_(2),is a kinetically complex and energetically challenging multistep reaction.Photocatalysis brings hope for this challenge,but obstacles remain in many aspects.Here,aiming at the key difficulties of the photocatalytic activation and conversion of these three inert small molecules,i.e.,regulating electronic structure,active sites,charge carrier separation and mobility,and reaction energy barrier,we propose the concept of functional customization strategy of ultrathin two-dimensional materials for achieving more efficient activation and better performance,including thickness control,vacancy engineering,doping operation,single-atom site fabrication,and composite construction.The in-depth understanding of the functional customization will provide more profound guidance for designing photocatalysts that specialize in activating and converting inert small molecules.

Chlorine-Substituent Regulation in Dopant-Free Small-Molecule Hole-Transport Materials Improves the Effi ciency and Stability of Inverted Perovskite Solar Cells

Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the stability.Here,we describe the use of various chlorinated small molecules,specifi cally fl uorenone-triphenylamine(FO-TPA)-x-Cl[x=para,meta,and ortho(p,m,and o)],with diff erent chlorine-substituent positions,as dopant-free HTMs for PSCs.These chlorinated molecules feature a symmetrical donor-acceptor-donor structure and ideal intramolecular charge transfer properties,allowing for self-doping and the establishment of built-in potentials for improving charge extraction.Highly effi cient hole-transfer interfaces are constructed between perovskites and these HTMs by strategi-cally modifying the chlorine substitution.Thus,the chlorinated HTM-derived inverted PSCs exhibited superior effi ciencies and air stabilities.Importantly,the dopant-free HTM FO-TPA-o-Cl not only attains a power conversion effi ciency of 20.82% but also demonstrates exceptional stability,retaining 93.8%of its initial effi ciency even after a 30-day aging test conducted under ambient air conditions in PSCs without encapsulation.These fi ndings underscore the critical role of chlorine-substituent regulation in HTMs in ensuring the formation and maintenance of effi cient and stable PSCs.

Development of small molecule drugs targeting immune checkpoints

Immune checkpoint inhibitors(ICIs)are used to relieve and refuel anti-tumor immunity by blocking the interaction,transcription,and translation of co-inhibitory immune checkpoints or degrading co-inhibitory immune checkpoints.Thousands of small molecule drugs or biological materials,especially antibody-based ICIs,are actively being studied and antibodies are currently widely used.Limitations,such as anti-tumor efficacy,poor membrane permeability,and unneglected tolerance issues of antibody-based ICIs,remain evident but are thought to be overcome by small molecule drugs.Recent structural studies have broadened the scope of candidate immune checkpoint molecules,as well as innovative chemical inhibitors.By way of comparison,small molecule drug-based ICIs represent superior oral bioavailability and favorable pharmacokinetic features.Several ongoing clinical trials are exploring the synergetic effect of ICIs and other therapeutic strategies based on multiple ICI functions,including immune regulation,anti-angiogenesis,and cell cycle regulation.In this review we summarized the current progression of small molecule ICIs and the mechanism underlying immune checkpoint proteins,which will lay the foundation for further exploration.

Small molecule inhibitor DDQ-treated hippocampal neuronal cells show improved neurite outgrowth and synaptic branching

The process of neurite outgrowth and branching is a crucial aspect of neuronal development and regeneration.Axons and dendrites,sometimes referred to as neurites,are extensions of a neuron's cellular body that are used to start networks.Here we explored the effects of diethyl(3,4-dihydroxyphenethylamino)(quinolin-4-yl)methylphosphonate(DDQ)on neurite developmental features in HT22 neuronal cells.In this work,we examined the protective effects of DDQ on neuronal processes and synaptic outgrowth in differentiated HT22cells expressing mutant Tau(mTau)cDNA.To investigate DDQ chara cteristics,cell viability,biochemical,molecular,western blotting,and immunocytochemistry were used.Neurite outgrowth is evaluated through the segmentation and measurement of neural processes.These neural processes can be seen and measured with a fluorescence microscope by manually tracing and measuring the length of the neurite growth.These neuronal processes can be observed and quantified with a fluorescent microscope by manually tracing and measuring the length of the neuronal HT22.DDQ-treated mTau-HT22 cells(HT22 cells transfected with cDNA mutant Tau)were seen to display increased levels of synaptophysin,MAP-2,andβ-tubulin.Additionally,we confirmed and noted reduced levels of both total and p-Tau,as well as elevated levels of microtubule-associated protein 2,β-tubulin,synaptophysin,vesicular acetylcholine transporter,and the mitochondrial biogenesis protein-pe roxisome prolife rator-activated receptor-gamma coactivator-1α.In mTa u-expressed HT22 neurons,we observed DDQ enhanced the neurite characteristics and improved neurite development through increased synaptic outgrowth.Our findings conclude that mTa u-HT22(Alzheimer's disease)cells treated with DDQ have functional neurite developmental chara cteristics.The key finding is that,in mTa u-HT22 cells,DDQ preserves neuronal structure and may even enhance nerve development function with mTa u inhibition.

Variation of microbiological and small molecule metabolite profiles of Nuodeng ham during ripening by high-throughput sequencing and GC-TOF-MS

The internal microbial diversity and small molecular metabolites of Nuodeng ham in different processing years(the first,second and third year sample)were analyzed by high-throughput sequencing technology and gas chromatography-time of flight mass spectrography(GC-TOF-MS)to study the effects of microorganisms and small molecular metabolites on the quality of ham in different processing years.The results showed that the dominant bacteria phyla of Nuodeng ham in different processing years were Proteobacteria and Firmicutes,the dominant fungi phyla were Ascomycota and Basidiomycota,while Staphylococcus and Aspergillus were the dominant bacteria and fungi of Nuodeng ham,respectively.Totally,252 kinds of small molecular metabolites were identified from Nuodeng ham in different processing years,and 12 different metabolites were screened through multivariate statistical analysis.Further metabolic pathway analysis showed that 23 metabolic pathways were related to ham fermentation,of which 8 metabolic pathways had significant effects on ham fermentation(Impact>0.01,P<0.05).The content of L-proline,phenyllactic acid,L-lysine,carnosine,taurine,D-proline,betaine and creatine were significantly positively correlated with the relative abundance of Staphylococcus and Serratia,but negatively correlated with the relative abundance of Halomonas,Aspergillus and Yamadazyma.

Reprogramming cell fates by small molecules

Reprogramming cell fates towards pluripotent stem cells and other cell types has revolutionized our under- standing of cellular plasticity. During the last decade, transcription factors and microRNAs have become powerful reprogramming factors for modulating cell fates. Recently, many efforts are focused on repro- gramming cell fates by non-viral and non-integrating chemical approaches. Small molecules not only are useful in generating desired cell types in vitro for vari- ous applications, such as disease modeling and cell- based transplantation, but also hold great promise to be further developed as drugs to stimulate patients＇ endogenous cells to repair and regenerate in vivo. Here we will focus on chemical approaches for generating induced pluripotent stem cells, neurons, cardiomy- ocytes, hepatocytes and pancreatic is cells. Significantly, the rapid and exciting advances in cellular reprogramming by small molecules will help us to achieve the long-term goal of curing devastating diseases, injuries, cancers and aging.

Controlling Morphology of Active Layer by Tuning Coplanarity of the Centrality in Acceptor-Donor-Acceptor Small Molecules for Photovoltaic Application

A series of acceptor-donor-acceptor alternative small molecules were synthesized containing electron-donating central building moieties of phenothiazine, 2,7-carbazole and thieno[3,4-b]thiophene and electron-accepting moie- ties of tetrazine on both sides. The various conformations of the central blocks, with the coplanarity in an order of phenothiazine〈2,7-carbazole〈thieno[3,4-b]thiophene, have an obvious influence on the optical, electrochemical property and the crystallinity of small molecule. In addition, the blend films between small molecule and （6,6）-phenyl-C6rbutyric acid methyl ester offered significantly various morphologies, changing from uniform sur- face to interpenetrated networks. As a result, the bulk heterojunction photovoltaic devices based on the three small molecules provided varied performance, and the highest coplanar molecule based device exhibited the best photo- voltaic performance.

Dynamical Entanglement of Vibrations in Integrable Dimer and Small Molecules

By means of the reduced-density linear entropy, we investigate the properties of dynamical entanglement of vibrations in integrable dimer and realistic small molecules which are initially in the two-mode squeezed vacuum state. It is found that the entropy of the integrable dimer is periodic for weak coupling strength cl and small squeezing parameter r, and there exists a beat phenomenon for strong el and large r. Moreover, the entropy of the small molecules is quasi-periodic for small r, ＆nd the begt phenomenon occurs in the entropy evolution of the two molecules C2D2 and S02 for large r. Our results might be used for molecular quantum computing based on vibrational states.

Recent Advances in Surface-Assisted Laser Desorption/Ionization Mass Spectrometry and Its Imaging for Small Molecules

Mass spectrometry imaging(MSI)has provided a new perspective on acquiring spatial information of multiple molecules in various samples.Among the different ionization methods,matrix-assisted laser desorption/ionization(MALDI)has been widely utilized for detecting macromolecules,with difficulty for small molecules(m/z<700 Da)due to the matrix interference or ionization suppression.In the past two decades,surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)gives rise to lots of attention on account of its unique performances,especially in untargeted analysis of small molecules.Selecting an appropriate substrate is a precondition for SALDI-MS and offers the possibility for SALDI-MS imaging(SALDI-MSI).In the last 5 years,different kinds of nanomaterials have been widely explored as substrates including metal/metal oxide-based,carbon-based,silicon-based,metal-organic frameworks-based,covalent organic frameworksbased substrates,with growing interests on composite materials and nanomaterials with homogeneous film structure.This review highlights recent advances of various nanomaterials as SALDI substrates,and their emerging imaging applications in botanic,forensic,metabolic and pathological fields.Finally,the merits and limitations of SALDI-MS are sketched out and some recommendations of this technique and its imaging are proposed.

Therapies for Tau-associated neurodegenerative disorders:targeting molecules,synapses,and cells

Advances in experimental and computational technologies continue to grow rapidly to provide novel avenues for the treatment of neurodegenerative disorders. Despite this, there remain only a handful of drugs that have shown success in late-stage clinical trials for Tau-associated neurodegenerative disorders. The most commonly prescribed treatments are symptomatic treatments such as cholinesterase inhibitors and N-methyl-D-aspartate receptor blockers that were approved for use in Alzheimer's disease. As diagnostic screening can detect disorders at earlier time points, the field needs pre-symptomatic treatments that can prevent, or significantly delay the progression of these disorders(Koychev et al., 2019). These approaches may be different from late-stage treatments that may help to ameliorate symptoms and slow progression once symptoms have become more advanced should early diagnostic screening fail. This mini-review will highlight five key avenues of academic and industrial research for identifying therapeutic strategies to treat Tau-associated neurodegenerative disorders. These avenues include investigating(1) the broad class of chemicals termed “small molecules”;(2) adaptive immunity through both passive and active antibody treatments;(3) innate immunity with an emphasis on microglial modulation;(4) synaptic compartments with the view that Tau-associated neurodegenerative disorders are synaptopathies. Although this mini-review will focus on Alzheimer's disease due to its prevalence, it will also argue the need to target other tauopathies, as through understanding Alzheimer's disease as a Tau-associated neurodegenerative disorder, we may be able to generalize treatment options. For this reason, added detail linking back specifically to Tau protein as a direct therapeutic target will be added to each topic.

Precision medicine in inflammatory bowel disease:Individualizing the use of biologics and small molecule therapies

The advent of biologics and small molecules in inflammatory bowel disease(IBD)has marked a significant turning point in the prognosis of IBD,decreasing the rates of corticosteroid dependence,hospitalizations and improving overall quality of life.The introduction of biosimilars has also increased affordability and enhanced access to these otherwise costly targeted therapies.Biologics do not yet represent a complete panacea:A subset of patients do not respond to first-line anti-tumor necrosis factor(TNF)-alpha agents or may subsequently demonstrate a secondary loss of response.Patients who fail to respond to anti-TNF agents typically have a poorer response rate to second-line biologics.It is uncertain which patient would benefit from a different sequencing of biologics or even a combination of biologic agents.The introduction of newer classes of biologics and small molecules may provide alternative therapeutic targets for patients with refractory disease.This review examines the therapeutic ceiling in current treatment strategies of IBD and the potential paradigm shifts in the future.

Recent Progress of Surface Passivation Molecules for Perovskite Solar Cell Applications

Due to the solution processable nature,the prepared perovskite films are polycrystalline with considerable number of defects.These defects,especially defects at interface accelerate the carrier recombination and reduce the carrier collection.Besides,the surface defects also affect the long-term stability of the perovskite solar cells(PVSCs).To solve this problem,surface passivation molecules are introduced at selective interface(the interface between perovskite and carrier selective layer).This review summarizes recent progress of small molecules used in PVSCs.Firstly,different types of defect states in perovskite films are introduced and their effects on device performance are discussed.Subsequently,surface passivation molecules are divided into four categories,and the interaction between the functional groups of the surface passivation molecules and selective defect states in perovskite films are highlighted.Finally,we look into the prospects and challenges in design noble small molecules for PVSCs applications.