Sensitive and reliable hybrid nanosensor (Co2+-CDs@R-CDs) for ratiometric fluorescent and colorimetric detecting NO2.

A ratiometric fluorescent and colorimetric detecting assay for NO2- was realized by a hybrid nanosensor (Co2+-CDs@R-CDs) utilizing firstly through the redox reaction of nitrite (NO2-) with Co2+, of which the hybrid nanosensor Co2+-CDs@R-CDs was fabricated by Co2+-doped carbon dots (Co2+-CDs) and a reference of red-emitting carbon dots (R-CDs). The ratiometric fluorescent linear detection range of NO2- was 2.5-45 µM and the limit of detection (LOD) was 0.068 µM with the response time of 120 s. While, the colorimetric linear detection range of NO2- was 2.5-60 µM and the LOD was 0.075 µM. In addition, a portable smartphone system which could measure the R (red), G (green), and B (blue) values of the fluorescence and the visible color of the coated Co2+-CDs@R-CDs paper strip-based sensor had also been developed and successfully applied to detect NO2- in sausage, pickles and tap water samples.

Sulfonyl Molecules Induced Oriented Lithium Deposition for Long-Term Lithium Metal Batteries.

Dendrites growth and unstable interfacial Li+ transport hinder the practical application of lithium metal batteries (LMBs). Herein, we report an active layer of 2,4,6-trihydroxy benzene sulfonyl fluorine on copper substrate that induces oriented Li+ deposition and generates highly crystalline solid-electrolyte interphase (SEI) to achieve high-performance LMBs. The lithiophilic -SO2 - groups of highly crystalline SEI accept the rapidly transported Li+ ions and form a dense inner layer of LiF and Li3 N, which regulate Li+ plating morphology along the (110) crystal surface toward dendrite-free Li anode. Thus, Li||Cu cells with lithiophilic SEI achieve an average deposition efficiency of 99.8 % after 700 cycles, and Li||Li cells operate well for 1100 h. Besides, Li||LiNi0.8 Co0.1 Mn0.1 O2 cells with modified SEI exhibit a capacity retention that is 14 times than that of conventional SEI. Even at -60 °C, Li||Cu cells reach stable deposition efficiency of 83.2 % after 100 cycles.

Effect of low-temperature degradation on the fatigue performance of dental strength-gradient multilayered zirconia restorations.

OBJECTIVES: Fatigue and low-temperature degradation (LTD) are the main factors contributing to zirconia restoration failure. This study evaluated the effect of LTD on the fatigue performance of the novel "strength & shade-gradient" multilayered zirconia restorations. METHODS: Discs (15 mm × 1.2 mm) of each yttria content layer from a newly developed strength-gradient multilayered zirconia were fabricated and under accelerated aging in an autoclave at 134℃ for 0 h, 32 h, and 64 h. Then, the phase transformation, microstructure, and mechanical properties after LTD were assessed. In addition, the crown samples, including the multi-Zir, 3Y-Zir, and 5Y-Zir were fabricated, and their monotonic and fatigue load before and after LTD, percentage of fatigue degradation (Sd) and the fracture morphology were investigated. Statistical analyses were performed using paired samples t-test (α' = α/3 = 0.017), one-way ANOVA and Weibull analysis. RESULTS: After LTD, the phase transformation, surface roughness, depth of transformed zone, and residual stress were increased and inversely associated with the yttria content. The indentation elastic modulus and hardness after LTD decreased; however, there was no significant difference between the different yttria content layers. The monotonic and fatigue load of multi-Zir restorations decreased, but their Weibull modulus increased, and Sd decreased, similar to 3Y-Zir. The crack origin was associated with the cervical region. CONCLUSION: These results show that although LTD reduces the absolute fatigue strength of strength-gradient multilayered zirconia restorations, it also reduces the effect of cyclic fatigue itself on the strength of zirconia (relative to monotonic strength), which might be due to the increase of residual stress. CLINICAL SIGNIFICANCE: The novel "strength & shade-gradient" multilayered zirconia restorations show a promising performance during in vitro LTD and fatigue test and their reliability to some extent is comparable to 3Y-Zir. Yet, further in vivo longitudinal studies are warranted to confirm their precise performance.

Fabrication of a porous Urea@MIL-100(Fe)/CI-MCC/SA hydrogel for All-In-One adsorption, removal and fluorescence monitoring of nitrite.

In this paper, a novel All-In-One Urea@MIL-100(Fe)/CI-MCC/SA hydrogel platform was generated by microcrystalline cellulose (MCC) functionalized with pH-response probe (CI), MIL-100 (Fe) and sodium alginate (SA), which was as a carrier of urea to adsorb, remove and monitor NO2-. Under acidic condition, the fluorescent hydrogel platform could produce N2, CO2 and H2O through the diazotization and redox reaction between urea and NO2- with a removal efficiency up to 99.8%, and could also character a good adsorption property for NO2- due to the positive charges of protonation (the maximum adsorption capacity was 21.67 mg g-1), and the adsorption kinetics conformed to pseudo-second-order model. By carried out the NO2- removal step in fluorescent hydrogel platform, NO2- could also be detected indirectly by sensing the changes of pH within 15 min. The linear response range was 0-0.005 M, and the detection limit (LOD) was 74 µM. These results demonstrated that this All-In-One Urea@MIL-100(Fe)/CI-MCC/SA hydrogel platform had great potential in environment. This strategy for the removal and monitoring of NO2- could be employed to related applications in water purification and environmental protection. ENVIRONMENTAL IMPLICATION: Nitrite is one of the important indicators of water monitoring, which is harmful to human and environment. The removal and monitoring of nitrite in industrial wastewater and surface water is very important, but there are no studies about it at present. Based on the fact that urea can react with nitrite to produce green products, we synthesized a novel functional hydrogel to achieve adsorption, removal and fluorescence monitoring of nitrite for the first time. Besides, the practicability of the material in environmental water samples was verified through the detection of nitrite in simulated wastewater.

Organophosphate Level Evaluation for the Poisoning Treatment by Enzyme Activation Regeneration Strategy with Oxime-Functionalized ZIF-8 Nanoparticles.

In this work, two nanometal-organic frameworks (NMOFs) of ZIF-8-1 and ZIF-8-2 were designed and synthesized with a "missing linker" defects strategy by using Oxime-1 and Oxime-2 as coligands, respectively. ZIF-8-2 exhibited an excellent performance in comparison to that of ZIF-8-1 in activating and regenerating the activity of BChE suppressed by demeton-S-methyl (DSM) and could rapidly detoxify DSM in poisoned serum samples within 24 min. Additionally, the synthesized fluorescence probe of IND-BChE with high quantum yields, large Stokes shifts, and superior water solubility could be used for the detection of both butyrylcholinesterase (BChE) and DSM in a lower LOD of 0.63 mU/mL (BChE) and 0.086 µg/mL (DSM). By the difference in fluorescent intensity of IND-BChE with and without ZIF-8-2, a highly linear relationship of IND-BChE with DSM concentration was found (R2 = 0.9889), and the LOD was 0.073 µg/mL. In addition, an intelligent detection platform of ZIF-8-2@IND-BChE@agarose hydrogel combined with a smartphone formed a point-of-care test for DSM -poisoned serum samples and also realized satisfactory results. Unlike other detection methods of nerve agents, this assay first combined an NMOF reactivator for detoxification and detection of BChE enzyme activity and then quantification of OP nerve agents, which was of great significance in treatment of organophosphate poisoning.

Simple method for visual detection of nitrite using fluorescence and colorimetry by poly (tannic acid) nanoparticles.

The nitration reaction of nitrite and phenolic substances was first used to identify and detect NO2- by taking fluorescent poly (tannic acid) nanoparticles (FPTA NPs) as sensing platform. With the low cost, good biodegradable and convenient water-soluble FPTA NPs, a fluorescent and colorimetric dual modes detecting assay was realized. In fluorescent mode, the linear detection range of NO2- was 0-36 µM, the LOD was as low as 3.03 nM, and the response time was 90 s. In colorimetric mode, the linear detection range of NO2- was 0-46 µM, and the LOD was as low as 27 nM. Besides, a smartphone with FPTA NPs@ agarose hydrogel formed a portable detection platform to test the fluorescent and visible color changes of FPTA NPs for NO2- sensing as well as for accurate visualization and quantitative detection of NO2- in actual water and food samples.

Ultrasensitivity Detecting AChE through "Covalent Assembly" and Signal Amplification Strategic Approaches and Applied to Screen Its Inhibitor.

An ultrasensitivity detecting assay for acetylcholinesterase (AChE) activity was developed based on "covalent assembly" and signal amplification strategic approaches. After hydrolyzing thioacetylcholine by AChE and participation of thiol in a self-inducing cascade accelerated by the Meldrum acid derivatives of 2-[bis(methylthio) methylene] malonitrile (CA-2), mercaptans triggered an intramolecular cyclization assembly by the probe of 2-(2,2-dicyanovinyl)-5-(diethylamino) phenyl 2,4-dinitrobenzenesulfonate (Sd-I) to produce strong fluorescence. The limit of detection for AChE activity was as low as 0.0048 mU/mL. The detection system also had a good detecting effect on AChE activity in human serum and could also be used to screen its inhibitors. By constructing a Sd-I@agarose hydrogel with a smartphone, a point-of-care detection of AChE activity was achieved again.

Tb3+-Doped Ag-MOFs for fluorescent detection of formaldehyde in a novel smartphone platform and its removal applications in milk products and wastewater.

As one kind of reactive carbonyl species (RCS), formaldehyde (FA) with a high concentration could be extremely toxic to living bodies as well as the environment. This paper reports a three-dimensional (3D) Tb3+@Ag-MOFs-based fluorescent probe for fast sensing of FA, which uses a novel turn-on mechanism based on the luminescence induced by Tb3+. The MOF sensor shows broad dynamic ranges of 0.1-1 mM for FA with the detection limit of 1.9 µM. For online and real-time detection of FA, a portable smartphone platform was employed to analyze the RGB values of the fluorescence by a smartphone application. By incorporating this probe into a polyacrylonitrile (PAN) layer, we synthesized a film composite that could effectively remove FA in real samples including milk and chemical factory wastewater, and the removal rate reached 98.52% and 95.38% respectively. Moreover, the potential of the film to remove gaseous FA was confirmed by experiments as well.

The mechanisms of immune-chemotherapy with nanocomplex codelivery of pTRP-2 and adjuvant of paclitaxel against melanoma.

Melanoma accounts for the highest proportion of all skin cancer deaths. Immune-chemotherapy has transformed anti-melanoma therapy and is a preferred first-line combination strategy for melanoma. We previously prepared dendritic cells (DCs) targeting the nanocomplex paclitaxel (PTX)-encapsulated sulfobutylether-ß-cyclodextrin (SBE)/mannosylated N,N,N-trimethyl chitosan (mTMC)/DNA (PTX/SBE-DNA/Man-TMC) for the co-delivery of pTRP-2 DNA and adjuvant PTX. The nanocomplex PTX/SBE-DNA/Man-TMC promoted DC maturation and antigen presentation and spur potent anti-melanoma immunity. However, the mechanism by which PTX/SBE-DNA/Man-TMC regulates the biological functions of DCs and T lymphocytes is unknown. Therefore, we explored the underlying signaling pathways and mixed leukocyte reactions, resulting in enhanced T cell-mediated anti-tumor immunity. Interleukin-12 secretion from nanocomplex-pulsed mouse bone marrow-derived DCs was inhibited by treatment with Toll-like receptor 4 (TLR-4), nuclear factor kappa-B (NF-κB), and a specific blocker of p38 mitogen-activated protein kinase (MAPK). The results revealed that TLR-4, NF-κB, and MAPK signaling pathways were essential anti-tumor immune responses regulation factors. Furthermore, mixed leukocytes pulsed with PTX/SBE-DNA/Man-TMC induced tumor cell apoptosis and arrested the cell cycle in G0/G1, significantly promoting the synergy. Thus, we concluded that the mechanism driving the PTX/SBE-DNA/Man-TMC immune-chemotherapy synergistic effect was multifactorial.

Injectable Chitosan-Based Thermosensitive Hydrogel/Nanoparticle-Loaded System for Local Delivery of Vancomycin in the Treatment of Osteomyelitis.

PURPOSE: Osteomyelitis, particularly chronic osteomyelitis, remains a major challenge for orthopedic surgeons. The traditional treatment for osteomyelitis, which involves antibiotics and debridement, does not provide a complete solution for infection and bone repair. Antibiotics such as vancomycin (VCM) are commonly used to treat osteomyelitis in clinical settings. VCM use is limited by a lack of effective delivery methods that provide sustained, high doses to entirely fill irregular bone tissue to treat infections. METHODS: We engineered a chitosan (CS)-based thermosensitive hydrogel to produce a VCM-nanoparticle (NPs)/Gel local drug delivery system. The VCM-NPs were formed with quaternary ammonium chitosan and carboxylated chitosan nanoparticles (VCM-NPs) by positive and negative charge adsorption to enhance the encapsulation efficiency and drug loading of VCM, with the aim of simultaneously preventing infection and repairing broken bones. This hydrogel was evaluated in a rabbit osteomyelitis model. RESULTS: The VCM-NPs had high encapsulation efficiency and drug loading, with values of 60.1±2.1% and 24.1±0.84%, respectively. When embedded in CS-Gel, the VCM-NPs maintained their particle size and morphology, and the injectability and thermosensitivity of the hydrogel, which were evaluated by injectability test and rheological measurement, were retained. The VCM-NPs/Gel exhibited sustained release of VCM over 26 days. In vitro tests revealed that the VCM-NPs/Gel promoted osteoblast proliferation and activity against Staphylococcus aureus. In vivo, VCM-NPs/Gel (with 10 mg vancomycin per rabbit) was used to treat rabbits with osteomyelitis. The VCM-NPs/Gel showed excellent anti-infection properties and accelerating bone repair under osteomyelitis conditions. CONCLUSION: The reported multifunctional NPs hydrogel system for local antibiotic delivery (VCM-NPs/Gel) showed bone regeneration promotion and anti-infection properties, demonstrating significant potential as a scaffold for effective treatment of osteomyelitis.

"Covalent-Assembly"-Based Fluorescent Probe for Detection of a Nerve-Agent Mimic (DCP) via Lossen Rearrangement.

The highly selective and sensitive fluorescence "light-up" probe, 5'-(dimethylamino)-2'-formyl-N-hydroxy-[1,1'-biphenyl]-2-carboxamide(PTS), has been fabricated for the nerve-agent mimic diethyl chlorophosphate (DCP). The probe is designed by combining two novel strategies of "covalent assembly" and Lossen rearrangement. Formation of a phosphoryl intermediate from DCP and a hydroxamic acid group in PTS yields an isocyanate that quickly undergoes Lossen rearrangement to produce an aniline that condenses intramolecularly to a fluorescent phenanthridine system. PTS shows superior properties to probe DCP, such as rapid response (within 100 s), low detection limit (10.4 nM), specificity, and excellent linearity (R2 = 0.9993) in the range from 2 to 16 µM. More importantly, its application of detecting DCP vapor has also been achieved with satisfying results.

CD44-targeted hyaluronic acid-curcumin reverses chemotherapeutics resistance by inhibiting P-gp and anti-apoptotic pathways.

Chemotherapeutic drug resistance poses a great challenge in cancer therapy. Drug efflux and anti-apoptotic processes are the two most common mechanisms leading to chemotherapy resistance. In this study, we focused on the applicability of curcumin (CUR) as a sensitizer for chemotherapeutics (doxorubicin [DOX] as the model drug) modified with hyaluronic acid (HA) as an effective therapeutic strategy against multidrug resistance (MDR) in cancer cells. We constructed an HA-CUR/DOX delivery system measuring approximately 180 nm with superior encapsulation efficacy and serum stabilities. In vitro, we found that HA modification could facilitate the efficient delivery of chemotherapeutics through CD44 receptor-mediated targeted delivery. MTT assay results confirmed that the combination of CUR and DOX/paclitaxel (PTX) had a significant synergistic effect and significantly reversed MDR. Further experiments including real-time polymerase chain reaction and western blotting proved that the main mechanisms by which CUR reversed MDR in tumor cells were inhibiting the expression and activity of P-glycoprotein (P-gp) and inducing apoptosis through mitochondrial pathway. Taken together, our new engineered tumor-targeting nanoparticle delivery system may have the potential for overcoming MDR in cancer.

A near-infrared fluorescent probe for selective and quantitative detection of fluoride ions based on Si-Rhodamine.

A highly selective fluorescent probe (SiROPS) based on Si-rhodamine (SiR) towards F- was investigated. SiROPS can realize the NIR detection of F- because of the long fluorescent wavelength (λex = 650 nm, λem = 669 nm). The near-IR optical and the ratiometric fluorescence type signaling were realized by employing fluoride-selective cleavage of the latent thiophosphinated probe in mixed aqueous media. The cleavage of F- to the ortho positions of dimethylphosphinothionyl group in the meso aryl involves the suppression of internal rotation upon phosphorylation of a reactive phenolate and the activating rotation of o-OH, which resulting in a large fluorescence "Turn-Off" response. The detection limit of the probe to F- was 48 nM in the dynamic range of 0.5 µM-20 µM. In addition, the proposed probe has been used to detect F- in water samples and toothpaste samples with satisfying results.

A "Turn-On" fluorescent probe for sensitive and selective detection of fluoride ions based on aggregation-induced emission.

Based on the fluorophore of 2-(2'-hydroxyphenyl)benzothiazole (HBT) with aggregation-induced emission (AIE) properties, a highly selective and sensitive fluorescent probe PBT towards F- was investigated. "Turn-On" fluorescence type signaling was realized by employing fluoride-selective cleavage of the latent thiophosphinated probe in mixed aqueous media. The probe is designed in such a way that the excited state intramolecular proton transfer (ESIPT) of the HBT moiety becomes blocked. The chemodosimetric approach of F- to the probe results in the recovery of the ESIPT by removal of a free AIE-active HBT moiety through a subsequent hydrolysis process. The F- detection limit of the probe was 3.8 nM in the dynamic range of 0.5 µM to 10 µM. In addition, the proposed probe has been used to detect F- in water samples and toothpaste samples with satisfying results.

Side Chain Engineering on Medium Bandgap Copolymers to Suppress Triplet Formation for High-Efficiency Polymer Solar Cells.

Suppression of carrier recombination is critically important in realizing high-efficiency polymer solar cells. Herein, it is demonstrated difluoro-substitution of thiophene conjugated side chain on donor polymer can suppress triplet formation for reducing carrier recombination. A new medium bandgap 2D-conjugated D-A copolymer J91 is designed and synthesized with bi(alkyl-difluorothienyl)-benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit, for taking the advantages of the synergistic fluorination on the backbone and thiophene side chain. J91 demonstrates enhanced absorption, low-lying highest occupied molecular orbital energy level, and higher hole mobility, in comparison with its control polymer J52 without fluorination on the thiophene side chains. The transient absorption spectra indicate that J91 can suppress the triplet formation in its blend film with n-type organic semiconductor acceptor m-ITIC (3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(3-hexylphenyl)-dithieno[2,3-d:2,3'-d']-s-indaceno[1,2-b:5,6-b']-dithiophene). With these favorable properties, a higher power conversion efficiency of 11.63% with high VOC of 0.984 V and high JSC of 18.03 mA cm-2 is obtained for the polymer solar cells based on J91/m-ITIC with thermal annealing. The improved photovoltaic performance by thermal annealing is explained from the morphology change upon thermal annealing as revealed by photoinduced force microscopy. The results indicate that side chain engineering can provide a new solution to suppress carrier recombination toward high efficiency, thus deserves further attention.

Microneedle-Assisted, DC-Targeted Codelivery of pTRP-2 and Adjuvant of Paclitaxel for Transcutaneous Immunotherapy.

This work aims at developing an immunotherapeutic strategy to deliver a cancer DNA vaccine targeting dendritic cells (DCs), to trigger their maturation and antitumor function, and reduce immune escape using a polymeric nanocomplex of paclitaxel (PTX)-encapsulated sulfobutylether-ß-cyclodextrin (SBE)/mannosylated N,N,N-trimethylchitosan (mTMC)/DNA. To enhance DC-targeting and revoke immunosuppression is the major challenge for eliciting effective antitumor immunity. This codelivery system is characterized by using low-dose PTX as an adjuvant that is included inside SBE, and the PTX/SBE further serves as an anionic crosslinker to self-assemble with the cationic mTMC/DNA polyplexes. This system is used in combination with a microneedle for transcutaneous vaccination. Once penetrating into the epidermis, the mannosylated nanocomplexes would preferentially deliver the pTRP-2 DNA vaccine inside the DCs. Phenotypic maturation is demonstrated by the increased expression of costimulatory molecules of CD80 and CD86, and the elevated secretion of IL-12p70. The mixed leucocyte reactions reveal that the PTX/SBE-mTMC/DNA nanocomplexes enhance the proliferation of CD4+ and CD8+ T cells, and inhibit the generation of immune-suppressive FoxP3+ T cells. The system shows high antitumor efficacy in vivo. The PTX/SBE-mTMC/DNA nanocomplexes for DC-targeted codelivery of DNA vaccine and adjuvant PTX yield synergistic effects on the DC maturation and its presenting functions, thus increasing immune stimulation and reducing immune escape.

A mitochondria-targeting fluorescent probe for the selective detection of glutathione in living cells.

We report a fluorescent probe for the selective detection of mitochondrial glutathione (GSH). The probe, containing triphenylphosphine as a mitochondrial targeting group, exhibited ratiometric and selective detection of GSH over Cys/Hcy. The probe was used for imaging mitochondrial GSH in living HeLa cells.

A multi-emissive fluorescent probe for the discrimination of glutathione and cysteine.

Glutathione (GSH) and cysteine (Cys) play different roles in biological systems, thus the discrimination between them is of great importance. Herein we report a multi-emissive fluorescent probe for the selective detection of GSH and Cys. The probe was composed of covalently linked BODIPY and coumarin fluorophores. The BODIPY fluorophore was designed to react with GSH and Cys and generate different products with distinct photophysical properties, and the coumarin fluorophore acted as an internal standard. The probe exhibited green emission in aqueous solution. Upon addition of Cys, it yielded nitrogen-substituted BODIPY with weak fluorescence and free coumarin with blue emission. In the presence of glutathione, it generated mono- and di-sulfur substituted BODIPY and coumarin, resulting in various emission colors at different concentrations of GSH. Interestingly, the solution exhibited white fluorescence at GSH concentration of 0.4mM. The probe was capable of detecting and imaging GSH and Cys in living HeLa cells, indicating its significant potential in biological applications.

Naphthalenediimide-alt-Fused Thiophene D-A Copolymers for the Application as Acceptor in All-Polymer Solar Cells.

Three n-type alternating D-A copolymers based on a naphthalenediimide (NDI) acceptor (A) unit and three different donor (D) units with varied electron-donating strength including thiophene (P(NDI-T)), thieno[3,2-b]thiophene (P(NDI-TT)), and thieno[3,2-b;4,5-b]dithiophene (P(NDI-TDT)), were synthesized, for the application as acceptor materials in all-polymer solar cells (all-PSCs). The effect of the donor units of thiophene, thienothiophene (TT) and thienodithiophene (TDT) on the physicochemical and photovoltaic properties of the n-type D-A copolymers was systematically investigated. It was found that the absorption spectrum is red-shifted and the energy band gap (Eg ) is reduced for the NDI-based D-A copolymers with increasing number of thiophene rings in the thiophene or fused thiophene donor units. All-PSCs were fabricated with the medium band gap conjugated polymer J51 (Eg of ca 1.9 eV) as polymer donor and the n-type D-A copolymers as acceptor. The power conversion efficiency reached 2.59 %, 3.70 % and 5.10 % for the all-PSCs with P(NDI-T), P(NDI-TT), and P(NDI-TDT) as acceptor, respectively. The results indicate that a larger conjugated fused molecular plane with more thiophene rings as donor units in the NDI-based D-A copolymers is beneficial to reduce the band gap, broaden the absorption and enhance the photovoltaic performance of n-type D-A copolymer acceptors.

Insight into unresolved complex mixtures of aromatic hydrocarbons in heavy oil via two-dimensional gas chromatography coupled with time-of-flight mass spectrometry analysis.

The aromatic hydrocarbon fractions of five crude oils representing a natural sequence of increasing degree of biodegradation from the Liaohe Basin, NE, China, were analyzed using conventional gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography (GC×GC). Because of the limited peak capability and low resolution, compounds in the aromatic fraction of a heavily biodegraded crude oil that were analyzed by GC-MS appeared as unresolved complex mixtures (UCMs) or GC "humps". They could be separated based on their polarity by GC×GC. UCMs are composed mainly of aromatic biomarkers and aromatic hydrocarbons with branched alkanes or cycloalkanes substituents. The quantitative results achieved by GC×GC-FID were shown that monoaromatic hydrocarbons account for the largest number and mass of UCMs in the aromatic hydrocarbon fraction of heavily biodegraded crude oil, at 45% by mass. The number and mass of diaromatic hydrocarbons ranks second at 33% by mass, followed by the aromatic biomarker compounds, triaromatic, tetraaromatic, and pentaaromatic hydrocarbons, that account for 10%, 6%, 1.5%, and 0.01% of all aromatic compounds by mass, respectively. In the heavily biodegraded oil, compounds with monocyclic cycloalkane substituents account for the largest proportion of mono- and diaromatic hydrocarbons, respectively. The C4-substituted compounds account for the largest proportion of naphthalenes and the C3-substituted compounds account for the largest proportion of phenanthrenes, which is very different from non-biodegraded, slightly biodegraded, and moderately biodegraded crude oil. It is inferred that compounds of monoaromatic, diaromatic and triaromatic hydrocarbons are affected by biodegradation, that compounds with C1-, C2-substituents are affected by the increase in degree of biodegradation, and that their relative content decreased, whereas compounds with C3-substituents or more were affected slightly or unaffected, and their relative content also increased. The varying regularity of relative content of substituted compounds may be used to reflect the degree of degradation of heavy oil. Moreover, biomarkers for the aromatic hydrocarbons of heavily biodegraded crude oil are mainly aromatic steranes, aromatic secohopanes, aromatic pentacyclotriterpanes, and benzohopanes. According to resultant data, aromatic secohopanes could be used as a specific marker because of their relatively high concentration. This aromatic compound analysis of a series of biodegraded crude oil is useful for future research on the quantitative characterization of the degree of biodegradation of heavy oil, unconventional oil maturity evaluation, oil source correlation, depositional environment, and any other geochemical problems.