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Hydrogen sulfide (H2S) typically plays biphasic biological roles in living organisms with subnormal H2S exerting cytoprotective effects such as participating in cardioprotective signaling pathways while H2S with higher-than-normal concentrations in localized tissues acting the opposite way such as inhibiting mitochondrial respiration. Such concentration-dependent biological and pathological roles of H2S with the wide involvement of mitochondria and the elusive feature of H2S definitely highlight the vital significance of fast and precise estimation of the physiological level of H2S in specific microenvironments, particularly within cellular mitochondria. In this work, we developed a new type of fluorescent probe (QcyCHO) featured with H2S-triggered off-to-on near-infrared (NIR) fluorescence conversion within ~ 10 min, limit of detection (LOD) down to 8.3 nM, and high recognition specificity over other similarly interfering species. The ideal mitochondrion-targeting ability, high recognition specificity over typical interfering substances and other physiologically relevant species, and the ability for mapping intracellular H2S in living cells of QcyCHO probe were also unequivocally confirmed, which imply its potential for shedding light on the biology of H2S and therapeutic development in H2S-associated diseases by identifying the specific physiological stimuli inducing H2S production and determining the levels of H2S at the location and time of stimulation.

TiO2 is the most photoactive material because of its superstrong photooxidizing ability, and TiO2 photocatalysis has been widely applied in sustainable water treatment and environmental remediation. However, poor sunlight or visible-light harvesting efficiency and fast recombination rate of the photogenerated charge carriers severely limit the practical applications of TiO2. To overcome these problems, the present work demonstrates a facile in-situ co-condensation method combined with hydrothermal treatment to prepare a series of graphitized carbon/TiO2 composite photocatalysts, and anatase TiO2 phase and π-π-conjugated polycyclic aromatic carbon structure are created simultaneously. As-prepared TiO2/C composites exhibit remarkably high visible-light photocatalytic activity in the degradation of aqueous emerging phenolic pollutants, acetaminophen (APAP) and methylparaben (MPB), and apparent rate constant of the TiO2/C composite with carbon doping level of 10.3% for APAP and MPB removal is 7.6 and 2.8 times higher than that of bare TiO2, and 6.2 and 2.6 times higher than that of Degussa P25 TiO2. Based on the results of photoelectrochemical experiments, indirect chemical probe measurements, and ESR spectroscopy, it is verified that doping TiO2 with graphitized carbon is responsible for this enhanced photocatalytic activity, which renders the improved visible-light harvesting ability, the accelerated separation of the photogenerated charge carriers, and enlarged BET surface areas. Through analyzing the intermediates yielded in the photodegradation process, the pathway of visible-light photocatalytic degradation of APAP and MPB over the TiO2/C composite is proposed.

Graphitic carbon nitride (g-C3N4) offers exciting opportunities for sustainable photocatalytic oxidation of organic pollutants but suffers from drawbacks of insufficient oxidation driving force and low quantum efficiency. To over the drawbacks, here a simple and effective strategy was developed to engineer g-C3N4 with simultaneous interstitially embedded potassium dopant and nitrogen defects, and the process included supramolecular preorganization followed by KOH-assisted thermal polycondensation. In the prepared DN-K-CN catalysts, potassium doping level and the amount of nitrogen defects were both controllable. With the increment of potassium doping level, the bandgap of the DN-K-CN became narrow, along with continuously downshifted valence band position. The DN-K-CN showed greatly enhanced visible-light photocatalytic oxidation performance with respect to g-C3N4 in the degradation of emerging phenolic pollutants, acetaminophen and methylparaben; meanwhile, the oxidation performance of DN-K-CN depended on potassium doping level and the amount of nitrogen defects. Combination of experimental findings and theory calculations it is confirmed that the enhanced photocatalytic oxidation performance of DN-K-CN was attributed to the synergistic effect of potassium dopant and nitrogen defects, which resulted in the generation of plentiful active oxygen species and the improvement of oxidation driving force of valence holes. The influence of potassium dopant and nitrogen defects on the electronic and band structures of g-C3N4 was revealed; simultaneously, mechanism of the enhanced photocatalytic oxidation performance of g-C3N4 after the introduction of potassium dopant and nitrogen defects was studied. The present work provided new insights into the electronic and band structure tuning for the improvement of the photocatalytic oxidation performance of g-C3N4.

Environmentally benign photocatalytic oxidation is one of the most promising approaches to remove volatile, highly toxic and refractory aromatics, and the key points of gas-phase photocatalytic oxidation of aromatics are to develop efficient photocatalysts and design suitable photoreactors. Here, the custom-designed H3PW12O40/g-C3N4 film-coated optical fiber photoreactor is demonstrated for gas-phase simulated sunlight photocatalytic removal of aromatics including benzene, toluene and m-xylene. At relative humidity of 73% and air atmosphere, the H3PW12O40/g-C3N4 film-coated optical fibers with H3PW12O40 doping level of 3.2% exhibit remarkably higher photocatalytic removal efficiency of benzene, toluene and m-xylene than that of the g-C3N4 film, and apparent rate constant of the H3PW12O40/g-C3N4 film for benzene, toluene and m-xylene removal is 2.42, 1.75 and 3.67 times higher than that of g-C3N4 film. The enhanced photocatalytic activity of the H3PW12O40/g-C3N4 film is ascribed to direct Z-scheme-dictated charge carrier migration mechanism, imparting not only superior photogenerated charge carrier separation ability but also undiminished redox capability of the photogenerated electrons and holes; additionally, the increased contact area of catalyst film with the substrates and improved light harvesting ability give rise to the important contribution to gas-phase photocatalytic removal of aromatics. Moreover, the catalyst film exhibits excellent adhesion, stability and recyclability, and the activity loss is negligible after total thirty times’ catalytic runs.

A single-chromophore-based photoactive agent (MB-DOPA) capable of rapid sensing of nanomolar hypochlorous acid (HOCl) and in-situ generating photocytotoxicity to cancer cells was developed using dopamine moiety as the recognition unit and methylene blue (MB) moiety as the fluorescence signaling unit. Specifically, HOCl triggered conversion of the nonfluorescent MB-DOPA to MB enabling far-red fluorescence emission (λmax ∼ 683 nm) and additional ability to photogenerate 1O2 species. Owing to the catechol nature of dopamine characterized with strong electron-donating property, MB-DOPA underwent HOCl-mediated conversion with response time of ∼20 s and a strong fluorescence OFF-to-ON contrast by a factor of more than 3000. The preliminary bioimaging results confirmed the intracellular HOCl sensing ability of MB-DOPA and the in-situ photodynamic therapy (PDT) effectiveness for inducing massive apoptosis of cancer cells. The figure of merits of MB-DOPA, including ability for sensing of nanomolar HOCl with high specificity, rapid response, practicality for intracellular fluorescence imaging, and the in-situ generation of 1O2 for killing tumor cells, is expected to enable diagnosis of early-stage oncogenesis based on the highly specific detection of abnormal HOCl levels in the transformed cells and the simultaneous treatment in biomedical applications.

A new type of single-chromophore-based photoactivatable prodrug (B-Cbl-3) enabling green-light-triggered chemotherapy and simultaneous photodynamic therapy with superb therapeutic efficacy was developed by conjugating a photoactive BODIPY derivative with an antitumor chlorambucil moiety. The optimized BODIPY moiety markedly enabled high efficient photogeneration of 1O2 and fluorescence emission with distinct colors before and after photorelease of chlorambucil. The preliminary biological experiment results have verified the efficient photorelease of chlorambucil from B-Cbl-3 and the huge contrast in cytotoxicity between them, superior combined therapeutic performance based on extraordinary low doses of drug and light irradiation, and ratiometric fluorescence imaging for in situ monitoring drug release. The salient superiority of B-Cbl-3 regarding alleviating the attenuation of triggering light caused by optically turbid tissue that short-wavelength lights typically encounters has also been verified.

Previous studies show that mortalin, a HSP70 family member, contributes to the development and progression of ovarian cancer. However, details of the transcriptional regulation of mortalin remain unknown. We aimed to determine whether NF‐κB p65 participates in the regulation of mortalin expression in ovarian cancer cells and to elucidate the underlying mechanism. Chromatin immunoprecipitation and luciferase reporter assay were used to identify mortalin gene sequences, to which NF‐κB p65 binds. Results indicated that NF‐κB p65 binds to the mortalin promoter at a site with the sequence ‘CGGGGTTTCA’. Using lentiviral pLVX‐NF‐κB‐puro and Lentivirus‐delivered NF‐κB short hairpin RNA (shRNA), we created ovarian cancer cell lines in which NF‐κB p65 was stably up‐regulated and down‐regulated. Using these cells, we found that downregulation of NF‐κB p65 inhibits the growth and migration of ovarian cancer cells. Further experimental evidence indicated that downregulation of NF‐κB p65 reduced mortalin, and upregulation of mortalin rescued the proliferation and migration of ovarian cancer cells reduced by NF‐κB p65 knockdown. In conclusion, NF‐κB p65 binds to the mortalin promoter and promotes ovarian cancer cells proliferation and migration via regulating mortalin.

Construction of highly efficient hollow nanosphere photocatalytic systems has been strongly attracting the attention of researchers. In the present work, nanopore enriched hollow carbon nitride nanospheres (HCNNSs) with a smaller particle size (200 nm) and a thinner shell thickness (40 nm) are successfully fabricated by a silica-nanocasting strategy. Such unique structures possess many advantages such as large BET surface area (122 m2 g−1), high light-harvesting ability, fast charge separation and transfer efficiency, plentiful exposed active sites and enhanced oxidation ability of photogenerated holes (h+VB). Therefore, HCNNSs in smaller sizes (HCNNS-200) exhibit extremely excellent visible-light photocatalytic efficiency towards the degradation of contaminants of emerging concern, e.g. levofloxacin (LEVO), in comparison with bulk g-C3N4 and HCNNSs in larger sizes (HCNNS-500). And it takes less than 10 min to finish the degradation of LEVO. The experimental results including those from indirect chemical probing, electron spin resonance, ion chromatography and high performance liquid chromatography-mass spectrometry confirm that h+VB and ˙O2− are the active species that are responsible for the mineralization of LEVO to NO3−, F−, H2O and CO2 under visible-light irradiation. Additionally, the degradation pathway of LEVO in the HCNNS-200 photocatalytic system is also proposed. It is expected that HCNNS-200 can be used as a promising photocatalyst for environmental remediation.

Novel hybrid fluorescent nanoparticles (NPs) characterized with salient features of fluorescence brightness, photostability and fluorescence lifetime were fabricated based on fluorescent dyes (DBQ-3PXZ) with thermal activation delayed fluorescence (TADF) and aggregation-induced emission (AIE) characteristics (aggregation-induced delayed fluorescence, AIDF). An amphiphilic polymer with oxygen-blocking properties was used as the host matrix, while small-molecular-weight antifade agents (singlet oxygen quencher and antioxidant) and a triplet energy barrier were incorporated in the hybrid NPs. The matrix polymer, which is capable of separating DBQ-3PXZ molecules from molecular oxygen, and the incorporated antifade agents, which are capable of suppressing the oxygen-mediated photodegradation of DBQ-3PXZ, contributed to the excellent photostability of the target hybrid NPs. The intrinsic AIE properties and the triplet energy barrier capable of confining the triplet excitons within the dye molecules jointly enabled the high fluorescing ability of DBQ-3PXZ dyes residing in the core part of the NPs. Additionally, the TADF nature of DBQ-3PXZ dye together with the protective role of the matrix polymer and antifade agents imparted long fluorescence lifetimes to the target NPs. The preliminary cell fluorescence imaging results verified the practicability of these feature-packed NPs for highlighting regions of interest and enabling high-resolution visualization of fine subcellular architectures; this unequivocally proclaims this probe to be an ideal tag for biological fluorescence imaging.

Metal-free g-C3N4 is a promising candidate for the next-generation visible light-responsive photocatalyst; however, high recombination probability of the photogenerated charge carriers on g-C3N4 limits its photocatalytic activity. To further increase the intrinsic photocatalytic activity of g-C3N4, here, perylene tetracarboxylic diimide–g-C3N4 (PDI/GCN) heterojunctions are prepared by one-step imidization reaction between perylene tetracarboxylic dianhydride (PTCDA) and g-C3N4 in aqueous solution. By the combination of various testing results, it is confirmed that the surface hybridization of PTCDA and g-C3N4 in the PDI/GCN heterojunctions via O═C–N–C═O covalent bonds occurs at lower PTCDA-to-g-C3N4 weight percentage. By selecting p-nitrophenol (PNP) and levofloxacin (LEV) as the target organic pollutants, the visible-light photocatalytic performance of the PDI/GCN heterojunctions is studied. It shows that the PDI/GCN heterojunction prepared at a PTCDA-to-g-C3N4 weight percentage of 1% exhibits remarkably...

In this work, an organic coating film was designed to have a porous microstructure together with a rough surface, and its matrix was covered with a low surface energy layer, so that it can be employed for oil/water separation based on its superhydrophobicity and superoleophilicity. First, a mixture solution of poly(styrene-block-butadiene-block-styrene) (SBS) and polydimethylsiloxane (PDMS) prepolymer was sprayed onto stainless steel mesh in a non-solvent vapor atmosphere of ethanol. After solvent evaporation, a porous coating film has been obtained. The film matrix was formed from SBS to have a nodular-microstructure, which was covered by the highly flexible PDMS prepolymer. Then, the PDMS prepolymer was cured to cover the nodular microstructure at 60 °C, which was chosen to be far below the glass transition temperature of polystyrene block of SBS in order to maintain the formed nodular microstructure. The microstructures of the obtained coating films were carefully characterized and analyzed. Water and oil contact angles on the coating films were measured to indicate their wetting properties of superhydrophobicity and superoleophilicity. The oil diffusion speed along the coating film and the oil swelling behavior were examined to suggest the advantages of the covering PDMS layer. The coating films have been employed for oil/water separation through self gravity-driven filtration, where oil could penetrate the coating film automatically while water retained. The oil separation rate was found to be higher than 99.0% and the flux was estimated to be greater than 162 L∙h−1 m−2. Moreover, the cycling tests suggest the satisfactory reusability of the coating film, implying its potential applications in oily wastewater treatment or oil spill recovery.

We herein developed a core-shell type antitumor nanoagent based on the synergistically reinforced oxidative stress and calcium overload to mitochondria, both of which were triggered by near-infrared (NIR) light. The folic acid (FA) moiety decorated on MOF shells enabled efficient cellular uptake of nanoagents. The upconversion nanoparticle (UCNP) core converted NIR light to ultraviolet (UV) light with the latter catalyzed Fe3+-to-Fe2+ reduction and simultaneously activated the photoacid generator encapsulated in the cavities of MOFs, which enabled the release of free Fe2+ and photoacidification of intracellular microenvironment, respectively. The overexpressed H2O2 in the mitochondria, highly reactive Fe2+ and acidic milieu synergistically reinforced Fenton reactions for producing lethal hydroxyl radicals in mitochondria. Moreover, the photoacidification of plasma induced calcium influx, leading to calcium overload in the mitochondria. The therapeutic potency of the nanoagent based on the dual mitochondrial damage has been unequivocally confirmed in cell- and patient-derived tumor xenograft models in vivo.

Targeting subcellular organelle with multilevel damage has shown great promise for antitumor therapy. Here, we report a core-shell type of nanoagent with iron (III) carboxylate metal-organic frameworks (MOFs) as shell while upconversion nanoparticles (UCNPs) as core, which enables near-infrared (NIR) light-triggered synergistically reinforced oxidative stress and calcium overload to mitochondria. The folate decoration on MOFs shells enables efficient cellular uptake of nanoagents. Based on the upconversion ability of UCNPs, NIR light mediates Fe3+-to-Fe2+ reduction and simultaneously activates the photoacid generator (pHP) encapsulated in MOFs cavities, which enables release of free Fe2+ and acidification of intracellular microenvironment, respectively. The overexpressed H2O2 in mitochondria, highly reactive Fe2+ and acidic milieu synergistically reinforce Fenton reactions for producing lethal hydroxyl radicals (•OH) while plasma photoacidification inducing calcium influx, leading to mitochondria calcium overload. The dual-mitochondria-damage-based therapeutic potency of the nanoagent has been unequivocally confirmed in cell- and patient-derived tumor xenograft models in vivo., Targeting damage to mitochondria has become an effective strategy antitumor therapies. Here, the authors report on nanoagents with upconversion nanoparticles as cores and photoacid-loaded MOFs as shells for NIR triggered Fenton reaction, acidification and calcium overload to provide synergistic mitochondrial damage.

With the widespread use, chlorinated organophosphorus flame retardants (Cl-OPFRs) as a new emerging contaminant have been widely detected in water environments over the last few years. In this study, the degradation of a typical Cl-OPFR, TCEP (tris (2-chloroethyl) phosphate), by electrochemical reduction was investigated. It was found that copper (Cu) foam as the cathode showed more rapid and effective degradation for TCEP, compared to other cathodes. When TCEP was at the low concentrations (0.1 and 1 mg L−1), its degradation by Cu foam could reach above 95% within 20 min, and the maximum rate constant was 0.127 min–1. TCEP reduction was little influenced by the co-existing humic substance and anions, except Cl−. Compared with the reported oxidation methods, electrochemical reduction showed fast and stable degradation for TCEP. For other types of Cl-OPFRs, electrochemical reduction displayed a fast and effective removal for tris (1,3-dichloro-2-propyl) phosphate but lower removal for tris (2-cholroisopropyl) phosphate who possessed methyl units in the branched chains, influencing its reducibility. Based on the product analysis and Fukui function calculation, the bonds of TCEP molecule were found to be gradually broken, and the three oxygen-ethyl-chlorine arms were cleaved one by one. The products including C6H13Cl2O4P (MW = 249.99278 Da), C4H9Cl2O4P (MW = 221.96105 Da) and C4H10ClO4P (MW = 188.0002 Da) were detected at 60 min reaction, and those intermediates showed much lower toxicities than TCEP according to the previous report. The findings may provide a promising treatment for Cl-OPFRs removal from aqueous environments and help understand their reductive fate.

Aromatic organophosphate flame retardant (OPFR) pollutants and biochars are commonly present and continually released into soils due to their increasingly wide applications. In this study, for the first time, the sorption of OPFRs on biochars was investigated. Although triphenyl phosphate (TPhP) and triphenylphosphine oxide (TPPO) have similar molecular structures and sizes, TPhP exhibited much faster and higher sorption than TPPO due to its stronger hydrophobicity, suggesting the dominant role of hydrophobic interactions in TPhP sorption. The π-π electron donor-acceptor (EDA) interactions also contributed to the sorption process, as suggested by the negative correlation between the sorption capacity of the aromatic OPFRs and the aromatic index (H/C atomic ratios) of biochar. Density functional theory calculations further showed that one benzene ring of aromatic OPFRs has no electrons, which may interact with biochar via π-π EDA interactions. The electrostatic attraction between the protonated P = O in OPFRs and the negatively charged biochar was found to occur at pH below 7. This work provides insights into the sorption behaviors and mechanisms of aromatic OPFRs by biochars.

Ultrathin two-dimensional (2D) g-C3N4 nanosheets (UCNS) are facilely prepared by liquid-exfoliation of the urea-derived g-C3N4 via an HCl-assisted hydrothermal treatment method. The UCNS are served as the novel visible-light-driven photocatalyst to degrade a typical organic pollutant, p-nitrophenol (PNP), in an aqueous solution. By the combination of the advantages of plentiful exposed active sites, fast photogenerated charge carrier separation rate, aligned energy levels and easy dispersion in an aqueous solution, the UCNS exhibit considerably enhanced visible-light photocatalytic activity toward the degradation of the target compound in comparison of their bulk g-C3N4 counterpart, melamine-derived g-C3N4 nanoparticles or Degussa P25 TiO2. The indirect chemical probe experimental results indicate that both the superoxide radicals and the photogenerated holes are responsible for the complete decomposition of PNP. Additionally, the UCNS can be reused at least four times without obvious activity loss and morphology change, exhibiting the excellent reusability in photodegradation aqueous organic pollutants.

In this study, flower-like MoS2 prepared using hydrothermal method has been designed to hybrid with Cu2O using Cu(NO3)2·3H2O as copper salt and salicylaldehyde as reducing agent. The as-prepared composite has been characterized by X-ray diffraction (XRD), Raman spectrometer, Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption, Electrochemical impedance spectroscopy (EIS) as well as density functional theory (DFT), etc. techniques. The results imply that the parent MoS2 synthesized in the first step has been transformed into amorphous state in the following solvothermal process. Therefore, the as-prepared composite is denoted as Cu2O/MoSx and used for testing its catalytic performance in the reduction of 4-NP by NaBH4. As expected, the as-prepared Cu2O/MoSx composite has absolute superiority in catalyzing the reduction of 4-NP by NaBH4 compared with the patent MoS2 and Cu2O, demonstrating the remarkable synergistic effect between MoSx and Cu2O. Possible relationship between the structure and properties of the as-prepared Cu2O/MoSx composite in the reduction of 4-NP by NaBH4 has been discussed in this study.

Searching for effective strategies of boosting charge carrier separation and improving photooxidation ability are highly desirable to design graphitic carbon nitride-based photocatalysts for efficient organic pollutant degradation. Here we demonstrate an in situ acid-induced self-assembly of melamine and sodium tungstate method combined with hydrothermal treatment, by forming WO3/melamine-cyanuric acid supramolecular complex, to fabricate porous sheet-like WO3/g-C3N4 heterojunctions with oxygen doping; meanwhile, the morphology of WO3/g-C3N4 nanosheets can be further regulated by selecting different short-chain carboxylic acids. The heterojunctions exhibit enhanced visible-light photocatalytic activity than bulk g-C3N4 and supramolecule-based g-C3N4 in degradation of phenolic pollutants, acetaminophen and methylparaben. The tests including active species trapping, photoelectrochemistry and photoluminescence firmly evidence that the extraordinary Z-scheme charge transfer manner plays dominated role to this excellent activity, which can accelerate charge carrier separation and retain powerful redox ability of electrons on conduction band of g-C3N4 and holes on valence band of WO3 simultaneously; additionally, porous sheet-like nanostructures and oxygen doping also positively influence the activity via improving light harvesting, providing plentiful active sites, shortening charge carrier migration distance and further facilitating charge carrier separation. LC−MS analysis and TOC monitoring find the target pollutants are completely degraded under oxidation of holes, superoxide and hydroxyl radicals.

As a typical kind of endogenous reactive nitrogen species, peroxynitrite (ONOO−) is believed heavily involved in the pathogenesis of many diseases such as inflammation, neurodegenerative conditions, and cardiovascular disorders. Precisely estimating ONOO− level in cell compartments is crucial for unraveling the biological relevance of ONOO− and enabling effective control of ONOO−-associated pathogenicity but suffers from serious difficulty owing to the daunting elusive features of ONOO−, namely nanomolar level physiological concentration and millisecond level biological half-life. A new fluorescent probe capable of detecting ONOO− with limit of detection down to 1.2 nM, response time less than 1s, and high recognition specificity over other similarly interfering species was developed in this work. For the probe constructed by conjugating an isatin moiety with an electron-withdrawing tricyanofuran (TCF) moiety, the former enabled a highly selective ONOO−-mediated oxidative decarbonylation reaction while the latter significantly improved the electrophilicity of the 3-position carbonyl group of isatin moiety and therefore accelerate the ONOO−-mediated nucleophilic attack, which eventually enabled prompt and efficient recognition reaction. For the decarbonylated product featured with a released primary aniline moiety, TCF acted as an acceptor for enabling an intramolecular charge transfer (ICT) process and the remarkable change in electronic feature upon reaction with ONOO−, which generated turn-on fluorescence with large contrast and therefore the basis for ONOO− sensing. The cell fluorescence imaging performed in this work definitely verified the capability of the probe for mapping intracellular ONOO−, despite the daunting elusive features of such physiological species.

Hydroxyl-modified graphitic carbon nitride (HUCN) with interconnected open-framework is fabricated by hydrolysis of urea-derived graphitic carbon nitride (UCN) in an aqueous NaOH solution followed by a self-assembly in dialysis process. Compared with bulk graphitic carbon nitride (UCN), HUCN possesses more advantages such as plentiful exposed active sites, fast photogenerated charge carrier separation rate and more negative conduction band edge potential. These advantages bestow the HUCN remarkably higher simulated sunlight photocatalytic reduction ability towards an aqueous Cr(VI) as compared with UCN. By the combination of the experimental results including photoelectrochemistry and electron scavenger with the DFT calculated electrostatic potential (ESP) distribution, a possible reaction mechanism for the simulated sunlight photocatalytic reduction of highly toxic and carcinogenic Cr(VI) to non-toxic Cr(III) is put forward tentatively.

From the perspective of the life cycle, this paper studied the carbon emissions of urban commuter traffic and their factors. It puts forth the calculation method of commuter traffic carbon emissions based on life cycle. Then, relying on the survey data of Xi'an City and the life cycle research at home and abroad, the authors calculated the urban commuter traffic carbon emission of respondents. Finally, the authors applied SPSS software in a multiple linear regression and established an urban commuter traffic carbon emission model based on life cycle. The authors found that: (1) carbon emissions from vehicles usage were up to about one-half of the total life cycle carbon emissions; (2) for buses, the fuel cycle was the main carbon source; and, for cars, using parking facilities was the main source of carbon emissions; and (3) factors affecting the commuter carbon emissions were travel distance, travel mode, age and high degree of education (Masters or PhD).