Chemical Components Research Articles

Optimization of ammonia nitrogen benchmarks and ecological risk assessment in monsoon freezing lakes based on species sensitivity distribution with Lake Chagan in northeastern China as an example

There is an urgent need to determine reasonable water-quality benchmarks and risk assessment results to accurately characterize the relationship between crop yield enhancement and ammonia nitrogen pollution caused by excessive nitrogen fertilizer application. Through the collection of monitoring data from 2016 to 2023 in Chagan Lake, the first development of ecological criteria for ammonia nitrogen and risk evaluation for Northeast China was carried out based on the secondary ecological risk models (the quotient value method and joint probability curve). In addition, the species sensitivity distribution (SSD) model is improved through the use of genetic algorithms to identify more suitable ammonia water-quality benchmarks for ecological risk assessment. The results showed that high ammonia nitrogen concentration in wet season is primarily influenced by agricultural irrigation and drainage activities, whereas the dry season is driven by low temperatures and the nitrogen and phosphorus concentrations. The biological benchmark of improved SSD model with a genetic algorithm has a maximum error reduction of 23.84 % compared with other distributions, which is more than twice that of the median water-quality benchmark under the traditional Class III water-quality standard and empirical formula. Risk evaluation using traditional water-quality standards leads to the overprotection of the biological environment. Evaluations using quotient value methods and joint probability curves yield consistent results. The severity of the ecological risk of ammonia nitrogen follows the order: wet season > flat season > dry season. Using a genetic algorithm to optimize SSD model can effectively reduce the uncertainty of the model, providing a more accurate and reasonable ammonia nitrogen water-quality benchmark. This study improves the evaluation of the ecological risk of ammonia nitrogen in Lake Chagan, provides ideas for reducing the uncertainty of the selection of ammonia nitrogen water-quality benchmarks, and effectively prevents the overprotection of the lake from ammonia nitrogen.

Physical and chemical characterization of chitin and chitosan extracted under different treatments from black soldier fly

The shell of Hermetia illucens L. contains considerable amounts of chitin, which has various biological activities. So far, few studies have focused on chitin of Hermetia illucens L. as a source of chitosan and oligosaccharides. There is great potential for utilizing Hermetia illucens L. chitin to produce chitosan films in biomaterials. We studied different extraction conditions for chitin and extracted it from black soldier fly (BSF) (Hermetia illucens L.). Three processing steps were adopted: (1) demineralization, (2) deproteinization, and (3) decolorization. The chemical components (moisture, ash, protein, fat, residual protein, and residual mineral contents) and physicochemical characteristics of the chitin and chitosan extracted under these three conditions were determined. In addition, Fourier transform infrared spectroscopy and X-ray diffraction were used to analyze the extracted chitin and commercial samples, and the results showed that demineralization–deproteinization–decolorization treatments could achieve the highest chitin yield (7.18 ± 0.11 %), chitosan yield (64.22 ± 0.79 %), and the best purity (residual protein 0.56 ± 0.01 % and residual ash 0.58 ± 0.04 %), making it the best treatment method. Using this method, the residues produced from farmed BSF can be recycled and used as a new source of chitin.

Chaihu Guizhi Decoction Prevents Cognitive, Memory Impairments and Sensorimotor Gating Deficit Induced by N-methyl-d-aspartate Receptor Antibody in Mice

Ethnopharmacological relevanceAnti-NMDAR encephalitis is one of the most common types of autoimmune encephalitis, primarily presenting with prodromal symptoms, such as fever and headache, followed by a range of neurological and psychiatric symptoms. Chaihu Guizhi Decoction (CGD), a traditional Chinese medicine formulated by Zhang Zhongjing in the Eastern Han Dynasty, has been effectively used in clinical practice to treat the symptoms of Taiyang and Shaoyang disorders, including fever, headache, and psychiatric disorders. Aim of the studyTo demonstrate the protective effects of CGD in an animal model of anti-NMDAR encephalitis and explore the potential mechanisms involved. Materials and methodsUHPLC-HRMS was used to identify CGD’s chemical components and serum metabolomic profiles. Network pharmacology and molecular docking were performed to predict potential targets of CGD for the treatment of anti-NMDAR encephalitis. The effect of CGD on anti-NMDAR encephalitis was evaluated using a mouse model induced by patients’ antibodies. Behavioral tests were performed to assess cognitive impairment and schizophrenia-like behaviors. The effect of CGD on the cell-surface NMDAR GluN1 subunit in cultured neurons treated with patient antibodies was detected by immunofluorescence. Golgi staining was used to observe morphological changes in hippocampal dendrites. The expression of NMDAR-interacting proteins and various neuroreceptors in the hippocampus were examined to validate the targets predicted using network pharmacology and molecular docking. ResultsCGD alleviated cognitive, memory, and sensorimotor gating deficits in mice treated with anti-NMDAR encephalitis patients’ antibodies. Further experiments demonstrated the effect of CGD in preventing NMDAR reduction both in vitro and in vivo. Meanwhile, CGD regulated NMDAR-interacting proteins and dopamine receptors but did not affect hippocampal dendritic morphology and synaptic density. Additionally, CGD modifies metabolic pathways associated with anti-NMDAR encephalitis and other neurological and psychiatric disorders. ConclusionsCGD exhibited protective effects against anti-NMDAR encephalitis by mitigating the antibody-induced reduction in NMDAR and NMDAR-interacting proteins.

A general unit hydrograph theory for water level and tidal range distributions in the Modaomen Estuary, China

Understanding the spatial distributions of river-tide dynamics in estuaries and their response to intensive human interventions is critical. However, the studies on the characteristics of the spatial distributions of water levels and tidal range are insufficient, with inadequate direct established empirical formulas. In this study, we propose a general and analytical water level and tidal range distribution model based on the recently proposed General Unit Hydrograph (GUH) theory and apply it to the Modaomen Estuary in China. Due to the intensive human interventions, the evolution of river-tide dynamics in the Modaomen Estuary was divided into three distinct periods: Pre-human, Transitional and Post-human Periods. The results show that the water level increased at the SZ station, yet decreased at other stations, thereby reducing the maximum water level gradient by approximately 9.08 × 10−6 on average from the Pre-human to the Post-human Periods. The tidal range generally increased along the channel and the absolute value of the maximum tidal range gradient decreased by approximately 54 % on average. Correspondingly, the positions of both maximum water level gradient and minimum tidal range gradient generally move seaward by approximately 27.25 km and 0.34 km, respectively. Additionally, the spatial distributions of river-tide dynamics tended more linear after human interventions. The satisfactory correspondence of the model outputs with observations at the six gauging stations along the Modaomen Estuary (with maximum RMSE values being 0.05 m for the water level and 0.03 m for the tidal range, respectively) indicate that the newly proposed GUH model could serve as a simple tool to describe the spatial distributions of water level and tidal range in a specific channel together with their response to anthropogenic modifications, which is also particularly useful for the identification of regime shifts in river-tide dynamics and sustainable water resources management in other highly human-modified estuaries worldwide.

Spectroscopic study of wemple-didomenico empirical formula and taucs model to determine the optical band gap of dye-doped polymer based on chitosan: Common poppy dye as a novel approach to reduce the optical band gap of biopolymer

Spectroscopic study of wemple-didomenico empirical formula and taucs model to determine the optical band gap of dye-doped polymer based on chitosan: Common poppy dye as a novel approach to reduce the optical band gap of biopolymer

Investigation on the oil permeation–adsorption–diffusion combined action mechanism of the adsorbed layer for flexible oil storage in waters

A novel method entitled flexible oil storage in waters is proposed, aiming to address the limitations of current oil storage systems and enhance the country's oil storage capacity. However, oil contamination severely restricts its applicability. To ensure the environmental sustainability of the method, the adsorbed layer is added outside the oil bladder, and the study investigates the material and the action mechanism of the adsorbed layer for flexible oil storage in waters. The results show that, with long breakthrough time and low oil concentration as criteria, the reed straw biochar is more suitable as the adsorbed layer filling material compared to the coconut shell and the apricot shell biochar and the fluorinated ethylene propylene copolymer is more suitable as the adsorbed layer membrane material compared to polyvinyl chloride. The adsorbed layer action mechanism involves multiple interactions, including permeation, adsorption, accumulation, and diffusion. They are coupled and together influence the adsorption effect. The empirical formula for the adsorbed layer's lifespan is derived, which helps in designing the adsorbed layer to satisfy specific lifespan requirements. This study provides theoretical and engineering guidance for the application of flexible oil storage in waters, contributing to the development of oil storage techniques.

Rapid determination of chlorate and perchlorate in tea by ion exchange chromatography-tandem mass spectrometry

Ion exchange chromatography-tandem mass spectrometry (IEC-MS/MS) has recently become the preferred method for detecting ionic substances in tea. In this study, an IEC-MS/MS method was developed for the rapid determination of chlorate and perchlorate residues in tea samples. The optimal sample extraction process, pretreatment column, and chromatographic and mass spectrometric conditions were systematically investigated. In the optimal process, the tea samples were ultrasonically extracted with methanol-water (13∶7, v/v), and a PRiME HLB SPE column was used to purify the sample extract. An AceChrom Hybri-A IEC column (150 mm×2.1 mm, 5.0 μm) was used for separation, and 100 mmol/L ammonium acetate-acetonitrile (40∶60, v/v) was used as the mobile phase for isocratic elution. The flow rate was 0.3 mL/min, the column temperature was 40 ℃, and the injection volume was 5.0 μL. The mass spectrometric data were collected in negative electrospray ionization mode combined with multiple reaction monitoring (MRM) mode to achieve the rapid and accurate separation and qualitative analysis of the desired chemical components. Quantification was performed using the internal standard (IS) method. The measurement results showed a good linear relationship when the mass concentrations of chlorate and perchlorate were between 2.00-200 and 1.00-100 μg/L, respectively, with correlation coefficients (r2) greater than 0.9990. The average recoveries of chlorate and perchlorate at three spiked levels of low, medium, and high ranged from 88.54% to 97.25% with relative standard deviations (RSDs, n=7) of 3.2%-5.2%. The limits of detection for chlorate and perchlorate were 12.0 and 8.0 μg/kg, respectively, while the limits of quantification were 40.0 and 26.6 μg/kg, respectively. The results of tests conducted to assess the linearity, specificity, accuracy, precision, and applicability of the method to the analysis of chlorate and perchlorate in 15 tea samples collected from a local market demonstrated its validity for the routine analysis of tea samples. The proposed method is simple, rapid, sensitive, and accurate, and can meet requirements for the rapid screening and quantitative analysis of residual trace chlorate and perchlorate in large quantities of tea samples.

Seminar: Functional Exposomics and Mechanisms of Toxicity-Insights from Model Systems and NAMs.

Significant progress has been made over the past decade in measuring the chemical components of the exposome, providing transformative population-scale frameworks in probing the etiologic link between environmental factors and disease phenotypes. While the analytical technologies continue to evolve with reams of data being generated, there is an opportunity to complement exposome-wide association studies (ExWAS) with functional analyses to advance etiologic search at organismal, cellular, and molecular levels. Exposomics is a transdisciplinary field aimed at enabling discovery-based analysis of the nongenetic factors that contribute to disease, including numerous environmental chemical stressors. While advances in exposure assessment are enhancing population-based discovery of exposome-wide effects and chemical exposure agents, functional screening and elucidation of biological effects of exposures represent the next logical step toward precision environmental health and medicine. In this work, we focus on the use, strategies, and prospects of alternative approaches and model systems to enhance the current human exposomics framework in biomarker search and causal understanding, spanning from bench-based nonmammalian organisms and cell culture to computational new approach methods (NAMs). We visit the definition of the functional exposome and exposomics and discuss a need to leverage alternative models as opposed to mammalian animals for delineating exposome-wide health effects. Under the "three Rs" principle of reduction, replacement, and refinement, model systems such as roundworms, fruit flies, zebrafish, and induced pluripotent stem cells (iPSCs) are advantageous over mammals (e.g., rodents or higher vertebrates). These models are cost-effective, and cell-specific genetic manipulations in these models are easier and faster, compared to mammalian models. Meanwhile, in silico NAMs enhance hazard identification and risk assessment in humans by bridging the translational gaps between toxicology data and etiologic inference, as represented by in vitro to in vivo extrapolation (IVIVE) and integrated approaches to testing and assessment (IATA) under the adverse outcome pathway (AOP) framework. Together, these alternatives offer a strong toolbox to support functional exposomics to study toxicity and causal mediators underpinning exposure-disease links. https://doi.org/10.1289/EHP13120.

Revelation of the high surface insulation performance of the electron-delocalized group through molecule self-assembly on alumina insulato

Surface modification of vacuum insulators is a promising way to improve their surface insulation performance but commonly used surface modification technologies in surface insulation area such as fluorination and plasmas treatment are unable to control the surface chemical components at the molecular level, which makes it hard to explore molecular groups with high surface insulation performance. In this paper, molecule self-assembly is introduced to control the surface molecular structure precisely and vacuum surface insulation performance of a special molecular structure electron-delocalized group is studied. Hexagonal phenyl group containing delocalized electrons and cyclohexyl group with the same hexagonal molecular structure but without delocalized electrons are grafted onto the surface of alumina insulators through molecule self-assembly. Secondary electron emission yield test shows that phenyl group endows alumina insulators lower SEY than cyclohexyl group. Correspondingly, phenyl group grafted alumina insulators show higher surface insulation performance than cyclohexyl group. The results indicate that group containing delocalized electrons can endow insulators higher surface insulation characteristics.

Spatially resolved chemical data for PM10 and oxidative potential source apportionment in urban-industrial settings

This study proposes the use of spatially resolved data to identify local sources contributing to PM10 mass concentration and OP in urban-industrial contexts. Over a 18-month monitoring campaign spanning from October 2020 to May 2022, a low-volume PM10 sampling device was employed at 12 sites in the Sacco River Valley, Italy. PM10 samples were analyzed for OP by applying the DTT, AA, and DCFH assays, and for 77 chemical parameters: the main chemical components (major elements, inorganic ions, EC, OC, levoglucosan) and the water-soluble and insoluble fractions of 28 elements. Source apportionment via PMF analysis on spatially resolved data revealed seven PM10 source contributions, notably biomass burning and soil dust. Biomass burning predominated in winter, while soil dust prevailed in summer. Spatial variability in source contributions was observed due to diverse biomass types, domestic heating, and proximity to the cement plant and transportation networks. Bubble maps and FPCA represented OP and PM10 source relationships, highlighting biomass burning as the main contributor to OPDTT and OPDCFH, while non-exhaust traffic contributed significantly to OPAA. Findings from this study provide valuable insights into planning effective air pollution mitigation policies aimed at enhancing air quality in urban-industrial contexts.

Curving and running resistance of freight trains: current experience with on-track measurements

Curving resistance affects the railway vehicle running through curves. For its estimation in train dynamics calculations, different empirical formulas are used in various countries. It is practically impossible to determine its exact value because of its dependency on various – to some extent random – parameters. In the framework of the experimental research of running resistance of freight trains at the Faculty of Transport Engineering of the University of Pardubice, measurements in regular operation conditions on the Czech railway network were realised in recent years. Because some of these results can be used to quantify the curving resistance, the applied evaluation methods and the relevant results are presented in this paper. Besides that, a new general formula of running resistance for freight trains, based on the measurement results, is proposed. Attention is also paid to the effect of track quality on the vehicle running resistance.

A New Correlation for Estimating Static Elastic Properties of Sandstone Formations: Case Study from Rumaila Oilfield

Evaluating the elastic characteristics of reservoir's rocks is crucial for the oil and gas sector to reduce risks throughout drilling and production operations. Elastic parameters are essential for prediction of wellbore stability, estimation of in-situ stresses, optimization of drilling performance and design of hydraulic fracturing. Depending on the type of formation, Elastic parameter is varied dramatically. Thus, a precise way to identify these characteristics is needed. Inaccurate assessment of elastic characteristics can result in excessive expenditure and inappropriate field development plans. Static elastic modulus (Est) can be determined through laboratory testing. Although laboratory measurement is the most precise approach to determine the elastic modulus, it requires a continuous core sample to acquire a complete profile of the formation's elastic characteristics. However, just a portion of the well is typically sampled for cores. On the other hand, wireline log data is applied to determine the dynamic modulus (Edyn), allowing for continuous assessment of elastic properties. Numerous characteristics of the rock, including consolidation, pore pressure and lithology affect the dynamic modulus. Thus, it needs to be converted to Static elastic modulus by empirical formulae. Several empirical equations have been proposed to convert dynamic Young's modulus to static Elastic modulus. Nevertheless, the validity of these relationships is restricted and exclusive to certain areas. This research seeks to establish a relationship between Dynamic modulus and static Elastic modulus for sandstone formation of Rumaila oil field. The suggested correlation provides accurate predictions of the static elastic modulus for the complete sandstone segment. The newly created correlation performed better than the previous correlations in predicting static elastic modulus with average absolute error of 8.69 %, and correlation coefficient of 0.9848. The newly established empirical correlation can assist geo-mechanical engineers in estimating continuous profile of the sandstone formation's static modulus.

Hydraulic and mechanical response of loess to different chemical components in root exudates

Hydraulic and mechanical response of loess to different chemical components in root exudates

Pell Leonardo numbers and their matrix representations

In this study, we investigate Pell numbers and Leonardo numbers and describe a new third-order number sequence entitled Pell Leonardo numbers. We then construct some identities, including the Binet formula, generating function, exponential generating function, Catalan, Cassini, and d’Ocagne’s identities for Pell Leonardo numbers and obtain a relation between Pell Leonardo and Pell numbers. In addition, we present some summation formulas of Pell Leonardo numbers based on Pell numbers. Finally, we create a matrix formula for Pell Leonardo numbers and obtain the determinant of the matrix.

Empirical formula model and process parameter optimization of two-dimensional ultrasonic-assisted grinding force based on 2.5D-Cf/SiC fiber orientation

Empirical formula model and process parameter optimization of two-dimensional ultrasonic-assisted grinding force based on 2.5D-Cf/SiC fiber orientation

A comprehensive strategy of lipidomics and pharmacokinetics based on ultra-high-performance liquid chromatography-mass spectrometry of Shaoyao Gancao Decoction.

Shaoyao Gancao Decoction (SGD), a traditional Chinese medicine, has been proven to have a good liver protection effect, but the mechanism and pharmacodynamic substances of SGD in the treatment of acute liver injury are still unclear. In this study, an ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) method was established to characterize 107 chemical components of SGD and 12 compounds absorbed in rat plasma samples after oral administration of SGD. Network pharmacology was applied to construct a component-target-pathway network to screen the possible effective components of SGD in acute liver injury. Using lipidomics based on UHPLC-Q-TOF-MS coupled with a variety of statistical analyses, 20 lipid biomarkers were screened and identified, suggesting that the improvement of acute liver injury by SGD was involved in cholesterol metabolism, glycerol-phospholipid metabolism, sphingolipid signaling pathways and fatty acid biosynthesis. In addition, the UHPLC-tandem MS method was established for pharmacokinetics analysis, and 10 potential active components were determined simultaneously within 12 min through the optimization of 0.1% formic acid water and acetonitrile as a mobile phase system. A Pharmacokinetics study showed that paeoniflorin, albiflorin, oxypaeoniflorin, liquiritigenin, isoliquiritigenin, liquiritin, ononin, formononetin, glycyrrhizic acid, and glycyrrhetinic acid as the potential active compounds of SGD curing acute liver injury.

Mechanically Flexible Self-Healing Mg(II)-Metallogel: Approach of Triggering the ROS-Induced Apoptosis in Human Breast Cancer Cells.

A self-assembly-directed thixotropic metallohydrogel (i.e., Mg-Tetrakis) of Mg(II)-metal salt and N,N,N',N'-tetrakis(2-hydroxy-ethyl)ethylenediamine (i.e., Tetrakis) was successfully achieved. The organic chemical component N,N,N',N'-tetrakis(2-hydroxy-ethyl)ethylenediamine was used as a low-molecular-weight gelator, and water was employed as the gel-forming solvent. The fabricated supramolecular metallohydrogel promisingly depicted viscoelastic and mechanoelastic behaviors, which are interpreted through various rheological parameters. The thixotropic behavior of the metallohydrogel is also well characterized through this rheological study. Field emission scanning electron microscopy microstructural analyses were performed to visualize the morphological arrangements of the metallohydrogel. The anticancer properties of the synthesized metallogels are investigated through this work. The cytotoxic potential of the metallohydrogel on the MCF-7 breast cancer cell line is critically examined. Reducing the growth of breast cancer cell line MCF-7 through the treatment of gel on the colony formation assay has been explored through the work. The antimigratory potential of the metallohydrogel on the MCF-7 cell was also scrutinized. The anticancer effect of the fabricated metallohydrogel is inspected through various assay formation strategies, like wound healing assay, tumor spheroid inhibition assay, nuclear fragmentation assay, and so on. Quantitative reactive oxygen species analysis of the cancer cells by treatment with the metallohydrogel was also conducted through this study. The mechanistic apoptosis study was executed by studying the expression of various apoptotic markers like BAX, BCL2, PUMA, and NOXA.

Pharmacodynamics of Sishen decoction in relieving rheumatoid arthritis: Chemical composition, regulatory pathway and online prediction simulation

As a commonly used traditional Chinese medicine formula for treating rheumatoid arthritis (RA), Sishen Decoction (SSD) has anti-inflammatory, analgesic and swelling relief effects. However, at present, the pharmacodynamic basis of SSD and its mechanism of treating RA have not been clarified, and further research is needed. Analyzing the pharmacological basis of SSD was the aim of our study and further elucidate its therapeutic mechanism and potential targets for treating RA. LC‒MS was used to identify the high content and characteristic chemical components of SSD. On this basis, a network of pharmacological analysis was established between the chemical structure and RA. According to the predicted possible pathways and targets, in vivo pharmacodynamic experiments and related pathway analysis were conducted. Finally, the possible targets and mechanisms of SSD in treating RA were analyzed. Identified 78 compounds from SSD by LC-MS, including 23 flavonoids, 19 phenolic acids, 9 monoterpenoids and 26 other compounds. Network pharmacological analysis based on pharmacodynamic substances revealed that the most likely interaction pathway between SSD and RA was the PI3K/AKT/mTOR pathway. Foot swelling and inflammatory factors (IL-6, IL-10, IL-18, TGF, TNF-α, VEGF) in model mice were shown to be significantly improved in vivo. WB and qPCR experiments proved that SSD could significantly regulate the pathway of PI3K/AKT/mTOR. The interaction between SSD and AKT target was further analyzed by multispectroscopy. This study revealed that SSD alleviates RA by regulating the pathway of PI3K/AKT/mTOR and preliminarily revealed the pharmacodynamic mechanism of SSD for the first time.

Growth and metabolism of halophilic Candida versatilis and Tetragenococcus halophilus in simultaneous and sequential fermentation of salted soy whey

This study investigated various strategies: mono-, simultaneous and sequential fermentation of halophilic Candida versatilis and Tetragenococcus halophilus to valorize salted whey, a side stream of salted tofu (pressed beancurd) production, with an ultimate goal of creating a soy sauce-like condiment. Growth, glucose, organic acids were monitored throughout fermentation, while free amino acids and volatile compounds were analyzed on the final days. In monoculture fermentation, both C. versatilis and T. halophilus thrived in salted soy whey. However, in co-culture fermentation, an antagonistic relationship was observed, wherein C. versatilis growth was slightly suppressed and T. halophilus was significantly inhibited. In C. versatilis-involved fermentations, no significant (p > 0.05) differences in key volatile and non-volatile chemical components were found among various fermentation modes. Key soy sauce-like volatile compounds, such as 4-ethylguaiacol and 4-ethylphenol, were detected in all C. versatilis-fermented salted soy whey, while T. halophilus primarily functioned as a lactic and acetic acids producer. This study highlights the potential of mixed culture fermentation involving soy sauce yeast and lactic acid bacteria for eventually developing a soy sauce-like condiment from salted soy whey, with C. versatilis playing a crucial role in flavour development. The findings suggest that fermenting of a single culture of C. versatilis in lactic acid-adjusted salted soy whey could be a viable and efficient choice for future production of soy sauce-like condiment.

Dynamic Chemistry of DNA-Based Nanoassemblies in Living Cells.

ConspectusIn recent years, the controlled assembly/disassembly of exogenous chemical components inside cells has become an emerging approach to regulating cell functions. However, the construction of dynamic material chemistry systems in living cells always remains highly challenging due to the complicated intracellular microenvironment. Nucleic acid is a category of biological components that can achieve efficient molecular assembly via specific base-pairing and perform biological functions in the intracellular microenvironment. Deoxyribonucleic acid (DNA) molecules exhibit the superior performance of intracellular assembly, including sequence programmability, molecule recognition ability, and nanostructure predictability, as well as the unique biological functions that traditional synthetic polymers do not carry, showing great superiority in the construction of dynamic material chemistry systems. Moreover, the technologies of DNA synthesis are relatively mature, and the conjugation of DNA with functional small molecules can be achieved through established chemical synthesis methods, facilitating the construction of DNA-based dynamic materials with more functions. In addition, a few specific DNA molecules have been proven to show responsiveness toward different stimuli, functioning as dynamic modules.In this Account, we summarize our recent work in dynamic chemistry of DNA-based nanoassemblies in living cells from the perspective of stimulus types including enzyme, H+, glutathione (GSH), adenosine triphosphate (ATP), and light. Upon the specific stimuli, DNA-based nanoassemblies undergo precise assembly in living cells, executing disassembly or aggregation, which consequently affects the functions and behaviors of living cells. In the first part, we describe the interactions between DNA-based nanoassemblies and intracellular enzymes, namely the enzymatic cleavage of intracellular enzymes on the DNA or RNA sequences. In the second part, we summarize the effects of H+ in lysosomes on DNA-based nanoassemblies, including the formation of a tetraplex i-motif structure and the decomposition of acid-degradable polymeric coating. In the third part, we discuss the mechanism of GSH responsiveness of DNA-based nanoassemblies, including the breaking of disulfide bonds and reduction-responsive nanoparticles. In the fourth part, we describe the ATP-mediated conformational transition for the specific release of functional RNA sequences. In the fifth part, we demonstrate the light-mediated spatiotemporally dynamic chemistry of DNA-based nanoassemblies. In summary, based on the achievements of our group in the study of dynamic chemistry of DNA-based nanoassemblies, the assembly, disassembly, and reassembly in living cells are well-controlled, the regulation of cellular functions are explored, and the new strategies for cancer therapeutics are demonstrated. We envision that our work on the dynamic chemistry of DNA-based nanoassembly is a new paradigm for constructing dynamic material chemistry systems inside living cells, and will facilitate the development of precision medicine.