Propylene Glycol Methyl Ether Acetate Research Articles

Synthesis of Propylene Glycol Methyl Ether Acetate: Reaction Kinetics and Process Simulation Using Heterogeneous Catalyst

Propylene glycol methyl ether acetate (PGMEA) serves as a crucial solvent in semiconductor and display material processes, demanding high purity and low acidity. Despite its significance, its conventional synthesis method using homogeneous catalysts requires extensive purification. Our study explores the use of Amberlyst-15, a stable solid catalyst, to streamline this process. Through batch reactions with a 1:1 reactant ratio at various temperatures and modeling using an integrated reaction rate equation, we obtained kinetic parameters. These parameters were used to predict the kinetics under different reactant ratios and different catalyst amounts, and the predictions match well with experimental results, especially when we used the catalyst amount scaled by the amount of the limiting reactant (PGME) rather than the total amount of the reactants. This highlights the importance of reporting kinetic parameters with proper scaling for catalyst used. Furthermore, we integrated these parameters into process simulations to determine the length of a plug flow reactor (PFR), constructed a PFR system, and confirmed that the simulation results matched well with experimental data obtained from the PFR system. Our findings suggest Amberlyst-15’s potential in simplifying PGMEA synthesis, promising advancements in industrial applications.

Adjustable photovoltaic performance driven by polarization in molecular ferroelectrics

The photovoltaic effect driven by ferroelectric polarization shows great application potential in photovoltaic devices. Two-dimensional (2D) Ruddlesden-Popper perovskite molecular ferroelectric materials, which combine polarization and low band gap properties, occupy a promising position in this field. However, literature reports mostly focus on single crystal blocks, and film devices are rarely reported. In this paper, 2D EA4Pb3Br10 (EA=ethylammonium) molecular ferroelectrics are used as the absorption layers to prepare photovoltaic devices, and the photovoltaic performance of the devices is enhanced by polarization. Dense EA4Pb3Br10 films are prepared by immediately adding antisolvent propylene glycol methyl ether acetate when the spin coating rate reaches the maximum. Surprisingly, the photovoltaic device exhibits significant photovoltaic effects under AM1.5 (100 mW/cm2) illumination with VOC ∼ 1.042 V and JSC ∼ 438.02 μA/cm2, which is much higher than that of ordinary inorganic ferroelectrics. In addition, the photovoltaic performance has been greatly improved by applying an external electric field, reaching to the maximum VOC ∼ 1.087 V and JSC ∼ 489.12 μA/cm2. This indicates the potential application prospects of 2D EA4Pb3Br10 molecular ferroelectric films in photovoltaic devices.

Molybdenum-Containing Dendritic Mesoporous Silica Nanospheres as Effective Catalysts for Synthesis of Propylene Glycol Methyl Ether Acetate

Molybdenum-Containing Dendritic Mesoporous Silica Nanospheres as Effective Catalysts for Synthesis of Propylene Glycol Methyl Ether Acetate

Solvent recovery from photolithography wastes using cellulose ultrafiltration membranes

Solvent recycling and reuse are indispensable for ensuring a sustainable chemical industry and circular economy. In this study we report the fabrication of cellulose ultrafiltration membranes and their application in recovery of propylene glycol methyl ether acetate (PGMEA) used as developer solvent in SU-8 photolithography. Cellulose membranes were fabricated via alkaline hydrolysis of cellulose acetate membranes in aqueous NaOH. Membrane permeance and molecular weight cut-off (MWCO) were tuned via changing cellulose acetate concentration in precursor solution and evaporation of volatile co-solvent, acetone. MWCO of the membranes was found to be smallest in DMSO, followed by water and largest in methanol. The difference was attributed to the different hydrodynamic diameters of the probe molecules in these solvents. SU-8 rejection from its representative developer solutions in PGMEA was assessed in dead-end filtration at up to 80% permeate recovery. After the first filtration, the collected permeate was fed to the same membrane to simulate a two-stage filtration scenario. Rejection was in the range of 87%–89% in a first stage filtration and 79%–80% in a second stage, both operated at 80% permeate recovery. Recycled solvent could be used in photolithography although with some loss of pattern fidelity, possibly owing to remaining SU-8 and photoacid generator in PGMEA. • Cellulose membrane permeance and MWCO tuned between 0.40–23.3 LHM/bar and 4–15 kDa. • Permeance is via pore flow mechanism but is also affected by swelling and steric hindrance. • SU-8 can be recovered from its PGMEA solution and reused in photolithography.

Fluorescent nitrogen-doped carbon nanodots synthesized through a hydrothermal method with different isomers

In this work, we have developed a novel fabrication technique for preparing N-functionalized carbon nanodots (CNDs) through one-pot hydrothermal route using various isomers, exhibiting highly intense fluorescence under blue light illumination. Three types of isomers, o-, m-, and p-phenylenediamine (PD), serving as the carbon and nitrogen sources were employed where the N/C atomic ratio in the CNDs structure was precisely tuned within the range of 20.2–25.7 at.% via tailoring the isomer precursors. The application of the m-PD precursor resulted in implanting the “lattice N” functionalities while the o-PD precursor enabled the formation of N-oxide groups. The CND suspensions in highly-polarity solvents (e.g., water and ethanol) emit intense fluorescence with ultrahigh quantum yield (QY: 85‒99%), whereas the fluorescence from the CND suspensions in propylene glycol methyl ether acetate is significantly quenched. The ultrahigh QY is majorly due to an intense radiative emission mechanism induced by the substitutional N atoms (via high electron-withdrawing) and N- and O-rich edge groups as the major contributors for boosting the affinity to high-polar solvents. Given the widespread applications of quantum dots as high-performance nanomaterials, this study paves the way for engineering N-functionalized CNDs to be used in optical, sensing, energy storage/conversion, and biological devices.

Effect of Solvent on Fluorescence Emission from Polyethylene Glycol-Coated Graphene Quantum Dots under Blue Light Illumination.

To explore aggregate-induced emission (AIE) properties, this study adopts a one-pot hydrothermal route for synthesizing polyethylene glycol (PEG)-coated graphene quantum dot (GQD) clusters, enabling the emission of highly intense photoluminescence under blue light illumination. The hydrothermal synthesis was performed at 300 °C using o-phenylenediamine as the nitrogen and carbon sources in the presence of PEG. Three different solvents, propylene glycol methyl ether acetate (PGMEA), ethanol, and water, were used for dispersing the PEG-coated GQDs, where extremely high fluorescent emission was achieved at 530–550 nm. It was shown that the quantum yield (QY) of PEG-coated GQD suspensions is strongly dependent on the solvent type. The pristine GQD suspension tends to be quenched (i.e., QY: ~1%) when dispersed in PGMEA (aggregation-caused quenching). However, coating GQD nanoparticles with polyethylene glycol results in substantial enhancement of the quantum yield. When investigating the photoluminescence emission from PEG-coated GQD clusters, the surface tension of the solvents was within the range of from 26.9 to 46.0 mN/m. This critical index can be tuned for assessing the transition point needed to activate the AIE mechanism which ultimately boosts the fluorescence intensity. The one-pot hydrothermal route established in this study can be adopted to engineer PEG-coated GQD clusters with solid-state PL emission capabilities, which are needed for next-generation optical, bio-sensing, and energy storage/conversion devices.

Synthesis of metallic nanoparticles for heterogeneous catalysis: Application to the Direct Borohydride Fuel Cell

Until now, the fabrication of electrocatalysts to guarantee long life of fuel cells and low consumption of noble metals remains a major challenge. The electrocatalysts based on metals or metal oxides which are used today are limited by the complexity of their synthesis processes and require several steps before depositing the catalysts on the substrate. Herein is described a chemical synthesis process that consists of a single-step synthesis and direct deposition of catalysts nanoparticles such as gold (Au), palladium (Pd) and platinum (Pt) in the thickness of a carbon-fibers-based porous transport layer (PTL). The synthesis process essentially consists of dissolving in the same PGMEA (Propylene glycol methyl ether acetate) solvent a metal precursor (HAuCl4 or PdNO2 or PtCl4) and a homopolymer PMMA (Polymethylmetacrylate), then the metal solution is deposited on the surface of the PTL after cleaning. Special emphasis is made on Pt-based materials. The obtained PTL-supported nanoparticles were firstly characterized by scanning electron microscopy (SEM) to evaluate their morphology, and then X-Ray diffraction (XRD) to observe the crystal phases. To validate the methodology, Pt-coated PTL materials have been used as anode for the borohydride oxidation reaction (BOR) in a direct borohydride fuel cell (DBFC) and compared to a state-of-the-art nickel electrode. There is an optimum loading of platinum (below 0.16 mg Pt / cm2) which constitutes the best compromise between power density and faradic efficiency for the borohydride oxidation reaction (BOR). Thanks to this low Pt loading, hydrogen evolved during the anodic reaction is completely valorized. These electrodes combine the advantages of high-performance with a very low metal loading, hence lowering materials’cost.

Highly fluorescent green and red emissions from boron-doped graphene quantum dots under blue light illumination

Highly fluorescent boron-doped graphene quantum dots (B-doped GQDs, average particle size of ∼4 nm) are synthesized via one-pot solvothermal route in the presence of 1,3,6-trinitropyrene (TNP) and boric acid. The chemical ratio of the boric acid to TNP precursor is identified as a crucial factor in modulating the B-dopant concentration within the GQD lattices. The GQD suspensions maintain uniform dispersion over extended operation thanks to the NO2 groups formed in the GQD edge sites promoting high dispersivity in polar and nonpolar solvents. The B-doped GQD suspensions are homogeneously stored in n-hexane and propylene glycol methyl ether acetate, enabling highly fluorescent green and red emission, respectively. Under the blue-light illumination, the green emission takes place at ca. 541 nm with a narrow full width at half maximum (FWHM) of 31.7 nm, whereas the red emission centers at ca. 617 nm with a FWHM of 42.5 nm. Through adjusting the concentration of B-dopant, the quantum yield of green and red fluorescence reached as high as 99.8 and 17.1%, respectively. Accordingly, the novel solvothermal synthesis route developed in this work provides the essential framework for engineering B-doped GQDs with tunable optical properties for high-performance biosensors and biomedical devices.

Confinement and Processing Can Alter the Morphology and Periodicity of Bottlebrush Block Copolymers in Thin Films.

Bottlebrush block copolymers (BBCPs) are intriguing architectural variations on linear BCPs with highly tunable structure. Confinement can have a significant impact on polymer assembly, giving rise to changes in morphology, assembly kinetics, and properties like the glass transition. Given that confinement leads to significant changes in the persistence length of bottlebrush homopolymers, it is reasonable to expect that BBCPs will see significant changes in their structure and periodicity relative to the bulk morphology. Understanding how confinement influences assembly will be important for designing BBCPs for thin film applications including membranes, integrated photonic structures, and potentially BCP lithography. In order to study the effects of confinement on BBCP conformation and morphology, a blade coating was used to prepare films with continuous variation in film thickness. Unlike thin films of linear BCPs, islands/holes were not observed, and instead mixtures of parallel and perpendicular morphologies emerge after annealing. The lamellar periodicity (L0) of the morphologies is found to be thickness dependent, increasing L0 with decreasing film thickness for blade coated films. Films coated out of tetrahydrofuran (THF) resulted in a single well-defined lamellar periodicity, verified through atomic force microscopy (AFM) and grazing incidence small-angle X-ray scattering (GISAXS), which increases dramatically from the bulk value (30.6 nm) and continues to increase as the film thickness decreases. The largest observed L0 was 65.5 nm, and this closely approaches the estimated upper limit of 67 nm corresponding to a fully extended backbone in a bilayer arrangement. Films coated out of propylene glycol methyl ether acetate (PGMEA) resulted in a mixture of perpendicular lamellae and a smaller, likely cylindrical morphology. The lamellar portion of the film shows the same thickness dependence as the lamellae observed in the THF coated films. The scaling of the lamellar L0 with respect to film thickness follows predictions for confined semiflexible polymers with weak excluded volume interactions and can be related to models for confinement of DNA. Spin coated films shows the same reduction in periodicity, although at very different film thicknesses. This result suggests that the material has shallow free-energy barriers to transitioning between different L0 and morphologies, a property that could be taken advantage of for patterning diverse structures with a single material.

Strategy for Enhancing Ultrahigh-Molecular-Weight Block Copolymer Chain Mobility to Access Large Period Sizes (>100 nm).

Assembling ultrahigh-molecular-weight (UHMW) block copolymers (BCPs) in rapid time scales is perceived as a grand challenge in polymer science due to slow kinetics. Through surface engineering and identifying a nonvolatile solvent (propylene glycol methyl ether acetate, PGMEA), we showcase the impressive ability of a series of lamellar poly(styrene)-block-poly(2-vinylpyridine) (PS-b-P2VP) BCPs to self-assemble directly after spin-coating. In particular, we show the formation of large-period (≈111 nm) lamellar structures from a neat UHMW PS-b-P2VP BCP. The significant influence of solvent-polymer solubility parameters are explored to enhance the polymer chain mobility. After optimization using solvent vapor annealing, increased feature order of ultralarge-period PS-b-P2VP BCP patterns in 1 h is achieved. Isolated metallic and dielectric features are also demonstrated to exemplify the promise that large BCP periods offer for functional applications. The methods described in this article center on industry-compatible patterning schemes, solvents, and deposition techniques. Thus, our straightforward UHMW BCP strategy potentially paves a viable and practical path forward for large-scale integration in various sectors, e.g., photonic band gaps, polarizers, and membranes that demand ultralarge period sizes.

Vapor–Liquid Equilibrium for the Binary of Propylene Glycol Methyl Ether Acetate + Ethyl Lactate and Propylene Glycol Methyl Ether + Ethyl Lactate at 101.3 and 20.0 kPa

In this work, the vapor–liquid equilibrium (VLE) data of propylene glycol methyl ether acetate + ethyl lactate and propylene glycol methyl ether + ethyl lactate was determined by a modified Rose–Wi...

Tuning the Wettability and Surface Free Energy of Poly(vinylphenol)Thin Films by Modulating Hydrogen-Bonding Interactions.

The ability to tune the surface properties of a polymer film in a simple and effective manner is important for diverse biological, industrial, and environmental applications. In this work, we investigated whether or not the surface free energy of poly(vinyl phenol; PVPh) can be tuned by adjusting the casting solvent and the thermal treatment time, which alters the proportions of intra-and intermolecular hydrogen bonding interactions. Compared to the untreated sample, in tetrahydrofuran (THF) system, the thermal treatment resulted in a lower proportion of intermolecular hydrogen bonds and a concomitant decrease in the surface free energy (from 39.3 to 18.8 mJ/m2). In contrast, the thermal treatment in propylene glycol methyl ether acetate (PGMEA) and ethyl-3-ethoxypropionate (EEP) systems increased the proportion of intermolecular hydrogen bonds and the surface free energy of the polymer thin films, from 45.0 to 54.3 mJ/m2 for PGMEA and from 45.5 to 52.9 mJ/m2 for EEP. Controlling intermolecular hydrogen-bonding interactions is a unique and easy method for tuning the surface free energies of polymer substances.

A layered titanosilicate AM-4 as a novel catalyst for the synthesis of 1-methoxy-2-propanole from propylene oxide and methanol

In this paper we report for the first time the catalytic properties of the titanosilicate AM-4 in the synthesis of 1-methoxy-2-propanol (PGME) from methanol and propylene oxide (PO). PGME is widely used as a pollution-free solvent and intermediate in the synthesis of propylene glycol methyl ether acetate, the herbicide metolachlor and in other industrial applications. We found that the catalytic properties of AM-4 could be adjusted by treatment with 0.0625–0.25 M HNO3. Increasing the concentration of HNO3 led to a decrease in basicity, which played a critical role in the reaction rate and the selectivity towards PGME. The yield of PGME decreased with increased acid concentration. The maximum conversion of PO (88.4%) and the selectivity towards PGME (92.3%) were found to be in the presence of AM-4 at 110 °C and 8 mol/mol MeOH/PO. Our results suggest that titanosilicate AM-4 has great potential for application in basic catalysis.

Health Risk Assessment of Photoresists Used in an Optoelectronic Semiconductor Factory.

Photoresist materials are indispensable in photolithography, a process used in semiconductor fabrication. The work process and potential hazards in semiconductor production have raised concerns as to adverse health effects. We therefore performed a health risk assessment of occupational exposure to positive photoresists in a single optoelectronic semiconductor factory in Taiwan. Positive photoresists are widely used in the optoelectronic semiconductor industry for photolithography. Occupational exposure was estimated using the Stoffenmanager® model. Bayesian modeling incorporated available personal air sampling data. We examined the composition and by-products of the photoresists according to descriptions published in the literature and patents; the main compositions assessed were propylene glycol methyl ether acetate (PGMEA), novolac resin, photoactive compound, phenol, cresol, benzene, toluene, and xylene. Reference concentrations for each compound were reassessed and updated if necessary. Calculated hazard quotients were greater than 1 for benzene, phenol, xylene, and PGMEA, indicating that they have the potential for exposures that exceed reference levels. The information from our health risk assessment suggests that benzene and phenol have a higher level of risk than is currently acknowledged. Undertaking our form of risk assessment in the workplace design phase could identify compounds of major concern, allow for the early implementation of control measures and monitoring strategies, and thereby reduce the level of exposure to health risks that workers face throughout their career.

Surface Engineering of Carbon-Based Microelectrodes for High-Performance Microsupercapacitors.

In this research, the enhancement in electrochemical performance of pyrolyzed carbon microelectrodes by surface modification is investigated. For the proposed microfabrication process, pyrolyzed carbon microelectrodes with multi-walled carbon nanotubes (MWCNTs) on their surface are obtained by developing GM-1060 photoresist in mixture of propylene glycol methyl ether acetate (PGMEA) and CNTs, and following pyrolysis of a micropatterned photoresist. Polyvinyl alcohol (PVA)/H2SO4 electrolyte (1 M) was applied to assemble this carbon/CNT microelectrode-based all-solid-state microsupercapacitor (carbon/CNT-MSC). The carbon/CNT-MSC shows a higher electrochemical performance compared with that of pyrolyzed carbon microelectrode-based MSC (carbon-MSC). The specific areal and volumetric capacitances of carbon/CNT-MSC (4.80 mF/cm2 and 32.0 F/cm3) are higher than those of carbon-MSC (3.52 mF/cm2 and 23.4 F/cm3) at the scan rate of 10 mV/s. In addition, higher energy density and power density of carbon/CNT-MSC (2.85 mWh/cm3 and 1.98 W/cm3) than those of carbon-MSC (2.08 mWh/cm3 and 1.41 W/cm3) were also achieved. This facile surface modification and optimization are potentially promising, being highly compatible with modern microfabrication technologies and allowing integration of highly electrically conductive CNTs into pyrolyzed carbon to assemble MSCs with improved electrochemical performance. Moreover, this method can be potentially applied to other high-performance micro/nanostructures and microdevices/systems.

Process integration for simulated moving bed reactor for the production of glycol ether acetate

This work designs and optimizes a simulated moving bed reactor (SMBR) within an overall process that includes two downstream units. The extract and raffinate streams are processed to improve product purity, and recycle streams leaving the downstream units are returned to the SMBR to reduce solvent consumption. Three different operating schemes are evaluated–the standard, limited superstructure, and full superstructure configuration.The proposed process flowsheet is optimized in a deterministic, nonlinear dynamic optimization scheme. The productivity of the target product, propylene glycol methyl ether acetate (PMA), is maximized while the minimum conversion is maintained between 70% and 99%, and the ratio of excess (solvent) reactant to the product is from 1.2 to 8. In addition to the standard configuration of SMBR, we found novel operating schemes through a superstructure formulation which allows feeding the recycle stream from downstream separation units. This work offers a realistic understanding of SMBR for implementation in an overall process flowsheet for industrial applications.

Experimental evaluation of simulated moving bed reactor for transesterification reaction synthesis of glycol ether ester

This work presents an experimental evaluation of multi-column simulated moving bed reactor (SMBR) technology for transesterification of glycol ether ester for the first time. An industrially relevant solvent, propylene glycol methyl ether acetate (DOWANOL™ PMA) was produced using a laboratory-scale SMBR unit packed with a base catalyst. The catalyst selected in this study, a Type-II anion exchange resin, was found to be resistant to deactivation through our experimental runs. To design the SMBR process, single-column experiments were first carried out to develop a mathematical model and estimate model parameters. Using this model, the optimal SMBR process was found by a multi-objective optimization technique to maximize the productivity while achieving high conversions. The optimal operating conditions found in this manner were implemented in the lab-scale SMB unit, which achieved conversions ranging from 47.3 to 57.7%. Furthermore, using the experimental data obtained from these experimental runs, the prediction of the model was improved via Tikhonov regularization, which was successfully validated in an additional run at an even higher conversion of 74.6%.

Albiflorin inhibits the formation of THP-1-derived foam cells through the LOX-1/NF-κB pathway

Foam cells are characteristic pathologic cells of atherosclerosis (AS), they are lipid-loaded macrophages present on atherosclerotic lesions. A large number of studies has shown that the pathogenesis of AS is the result of interactions between the lipid metabolism disorders and chronic inflammatory responses in the body. Albiflorin can inhibit the inflammatory response and it has shown a therapeutic effect on certain inflammatory diseases. In this study, a human acute monocytic leukemia cell line (THP-1)-derived foam cell model was established via oxidized low-density lipoprotein (ox-LDL) to observe the effects of albiflorin on the AS-characteristic foam cells. Our results showed that, after the treatment with ox-LDL, macrophages induced by propylene glycol methyl ether acetate (PMA), presented large amounts of lipid deposition in their cytoplasm, indicating that the THP-1-derived foam cell model was successfully established. On the other hand, the same cells pretreated with albiflorin presented significantly reduced amounts of lipid deposition, and their contents of total cholesterol and triglyceride were also clearly lower. Besides, the expression levels of low-density lipoprotein receptor-1 (LOX-1) and nuclear factor-κB (NF-κB) were significantly decreased, and the expression levels of downstream factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were also obviously decreased in the cells treated with albiflorin but not in the negative control cells. Moreover, after treatment of macrophages with different concentrations of ox-LDL, the expression levels of LOX-1 and NF-κB were up-regulated in an ox-LDL concentration-dependent manner, and so were the expression levels of IL-6 and TNF-α. And, it was found after treatment with LOX-1 neutralizing antibody or NF-κB inhibitor (during the foam cell formation induction via ox-LDL) that the lipid deposition in the cytoplasm of the cells was reduced, as in the cells treated with albiflorin. Taken together, our findings suggest that albiflorin decreases lipid deposition in the cytoplasm and blocks the foaming process by regulating the LOX-1/NF-κB signaling pathway.

Solvent assisted improvement of the dielectric properties and hysteresis behavior in poly‑4‑vinylphenol (PVP) thin films

The role of casting solvent, for casting the PVP dielectric layer in terms of variation in leakage current, dielectric constant and hysteresis voltage was investigated. The leakage current through the pristine (PVP) and cross linked PVP dielectric thin films cast with two different solvents namely Methanol and propylene glycol methyl ether acetate (PGMEA) was measured. Leakage current and dielectric constant in pristine PVP thin films reduced when low polarity solvent was used for casting the films (PGMEA in our case) and further reduced while PVP was cross linked with polymelamine‑co‑formaldehyde (MMF). This variation in the dielectric constant and the leakage current was attributed to the variation of the OH group density present at the polymer dielectric thin films cast with different solvents. The variation of OH group density among the samples was confirmed by the variation of 3290 cm−1 peak intensity, associated with hydroxyl group stretching, in FTIR spectra. Additionally, Contact angle study further revealed that the dielectric thin films cast with different solvents contained different amount of OH group density. Hysteresis voltage, observed in the MIS structure fabricated on these PVP thin films further confirmed variation in OH group densities. These results are critical for development of all organic FETs.

Characteristics of Treponema pallidum-induced macrophage-derived exosomes and its effect on proliferation of human umbilical vein endothelial cells

Objective To investigate characteristics of Treponema pallidum (Tp) -induced macrophage-derived exosomes and its effect on the proliferation of human umbilical vein endothelial cells (HUVEC) . Methods Tp strains were collected from the testis of male rabbit, which were infected with Tp (Nichols strain) . The human mononuclear macrophages (THP-1) were induced into macrophages by incubation with propylene glycol methyl ether acetate (PMA) , and then the macrophages were divided into 2 groups: experimental group incubated with Tp for 12 hours followed by 48-hour normal culture, and control group receiving normal culture. After the treatment, exosome suspensions were collected, and exosomes were extracted by differential centrifugation and exoEasy Maxi Kit. Transmission electron microscopy and Western blot analyses were performed to identify the exosomes, and nanoparticle tracking analysis (NTA) was conducted to measure the diameters and concentrations of exosomes. In vitro cultured HUVECs were divided into 3 groups, which were cultured with the 10 μl of suspensions containing exosomes derived from Tp-stimulated macrophages at a concentration of 4.5 × 108/ml (experimental group) , 10 μl of suspensions containing exosomes derived from untreated macrophages at a concentration of 4.5 × 108/ml (control group) , and 10 μl of exosome eluents (exosome eluent group) , respectively. After the treatment, confocal laser scanning microscopy was performed to observe the phagocytosis of exosomes of HUVECs, and cell counting kit-8 to evaluate the proliferative activity of HUVECs. Results The exosomes were saucer-like microvesicles with diameters of 30-100 nm under the transmission electron microscope. Western blot analyses showed that membrane proteins CD63, CD9 and CD81 were abundantly expressed by exosomes. Under the same conditions, NTA revealed that there were no significant differences in the particle diameter (u = 1.90, P > 0.05) and concentration of exosomes (Z=-1.604, P= 0.109) between the experimental group and the control group. After co-culture with HUVECs for 5 hours, confocal laser scanning microscopy showed scatteredly distributed exosomes with green fluorescence in the HUVECs in the experimental group and control group. After 12-hour co-culture with the exosome suspensions, the proliferative activity of HUVECs was significantly higher in the experimental group and the control group than in the exosome eluent group (both P 0.05) . At 72 hours, no significant differences in the proliferative activity of HUVECs were observed among the experimental group, the control group and the exosome eluent group (all P > 0.05) . Conclusions The exosomes secreted by THP-1 cells-derived macrophages evidently increased the proliferative activity of HUVECs within 48 hours, which peaked at 48 hours. After the stimulation with Tp, the exosomes secreted by THP-1 cells-derived macrophages were similar to those without Tp stimulation in morphology, size and concentration, and only increased the proliferative activity of HUVECs within 12 hours. Key words: Treponema pallidum; Macrophages; Exosomes; Human umbilical vein endothelial cells; Cell proliferation