Liquid Phase Plasma Research Articles

Synergistic N/F Dual-Doped MoC/C Catalyst Synthesized via Liquid Phase Plasma for Sustainable Ammonia Production.

NH3 is a versatile solution for the storage and distribution of sustainable energy, offering high energy density and promising applications as a renewable hydrogen carrier. However, electrochemical NH3 synthesis under ambient conditions remains challenging, such as low selectivity and efficiency, owing to the inertness of N≡N and competing reactions. In this study, a catalyst (MoC/NFC) comprising molybdenum carbide evenly dispersed on carbon doped with N and F heteroatoms was successfully synthesized using liquid-phase plasma. The MoC/NFC catalyst exhibited a maximum NH3 yield of 115 μg h-1 mg-1cat. with a faradaic efficiency of 1.15% at -0.7 V vs reversible hydrogen electrode in 0.1 M KOH electrolyte. Pyridinic- and pyrrolic-N atoms adjacent to the carbon pores served as active sites for N2 adsorption and enabled N2 triple bond cleavage. In addition, F doping contributed to N2 activation owing to the high electronegativity of 3.98, resulting in the attraction of more electrons. These findings demonstrate a significant advancement in the development of efficient catalysts for electrochemical ammonia synthesis, potentially paving the way for scalable and sustainable NH3 production methods that can support the growing demand for renewable energy storage solutions.

Femtogram-Sensitive Cantilever Platform for Dynamic Graphene Oxide Nanosheet Monitoring.

This study introduces a new approach to optimizing graphene oxide (GO) properties using liquid-phase plasma treatment in a microenvironment. Our innovation exploits atomic force microscopy (AFM) cantilever frequency tracking to monitor mass variations in GO, which are indicative of surface oxidation-reduction processes or substituent doping (boron/nitrogen). Complementary in situ Raman spectroscopy has observed D/G band shifts, and X-ray photoelectron spectroscopy (XPS) determined the C/O ratio and B/N doping levels pre- and post-treatment, confirming chemical tuning to GO. We can achieve femtogram-level precision in detecting nanomaterial mass changes by correlating elemental ratios with AFM cantilever frequency measurements. This multifaceted approach not only enhances our understanding of the chemical properties of GO but also establishes a new, versatile method for monitoring, modifying, and optimizing the properties of nanomaterials.

Surface Modification of Chromium–Nickel Steel by Electrolytic Plasma Nitriding Method

Electrolytic plasma nitriding is an attractive chemical heat treatment used to improve the surface properties of steel by implementing nitrogen saturation. This method is widely applied to steel and iron-based alloys operating under various operating conditions. In this work, using liquid-phase plasma nitriding technology, a nitrided layer was obtained on the surface of 40CrNi steel in electrolytes of different concentrations. The microstructure and phase composition of the nitrided layer were investigated and analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and we performed Vickers hardness and wear resistance tests using the ball-on-disc method. The microhardness and wear resistance of nitrided 40CrNi steel were significantly improved due to the lubricating properties of the ε-Fe2N phase formed on its surface.

Evaluating a green liquid phase plasma discharge process and working mechanism for remediating cobalt contamination in water

Cobalt is a toxic heavy metal contaminant in water and wastewater causing health concerns and on the other hand, a valuable element to recycle. In this study, performance of a novel and green continuous liquid phase plasma discharge (CLPD) process was investigated for removal and recovery of cobalt from aqueous solution without use of any catalysts or chemicals. The CLPD reactor design features two conductive channels and stable electric discharge at the orifice of two dielectric plates sandwiched among the electrodes. The effects of operating factors of the CLPD process were evaluated with liquid flow rate (25–100 mg/L) and applied power (200–300 W), and the highest removal efficiency of cobalt (93 %) was obtained within 25 min at a 50 ml/min liquid flow rate and 300 W applied power. The CLPD energy efficiency for cobalt removal under this condition was 27.44 g kW-1h−1. Reaction kinetics with scavenger tests revealed that oxidative reactive species, i.e., hydroxyl radical and superoxide radicals, produced at the discharge zone were responsible for cobalt removal from water by producing cobalt oxide particles and the reaction pathways were proposed. The CLPD process not only allowed for the efficient removal of cobalt (II) from water but also synthesized cobalt oxides particles with averaged size of 2.75 µm, which can be applied as catalyst. The overall results indicated that the novel CLPD is a robust and highly effective process to remove and recover cobalt from water.

Plasma-assisted synthesis of ultra-fine NiCo2O4/NiCo-layered double hydroxides nanoparticles-decorated electrospun carbon nanofibers with enhanced electrochemical performance

Nickel cobaltate/NiCo-layered double hydroxides (NiCo2O4/NiCo-LDH) as energy storage materials offer considerable potential for various applications. However, many of current methods for synthesizing NiCo2O4/NiCo-LDH suffer from long synthesis times, complex preparation process, and high temperatures and high pressures. In this study, we present a green, simple, and efficient approach known as assisted liquid-phase plasma electrolysis, which realizes the rapid fabrication of ultra-fine NiCo2O4/NiCo-LDH nanoparticle-decorated electrospun carbon nanofibers (NiCo2O4/NiCo-LDH/CNFs) composites. Ultra-fine NiCo2O4/NiCo-LDH nanoparticles (<70 nm) are uniformly deposited on the CNF surface. The CNFs are intertwined to form a highly conductive three-dimensional mesh structure, which synergizes the NiCo2O4/NiCo-LDH nanoparticles with a high specific capacitance in favor of ion/electron transport efficiency. In addition, the cooperative effect between the two phases of NiCo2O4 and NiCo-LDH further improves the electrochemical properties. The NiCo2O4/NiCo-LDH/CNFs composites exhibit a high specific capacitance of 1534.7 F/g at 1 A/g and a capacitance retention of 93.9 % after 5000 cycles. An assembled asymmetric supercapacitor using activated carbon and NiCo2O4/NiCo-LDH/CNFs composites achieves an energy density of 33.8 Wh/kg at a power density of 400 W/kg and a capacitance retention of 93.0 % after 5000 cycles. Notably, two series-connected NiCo2O4/NiCo-LDH/CNFs ASC supercapacitors can light up an LED bulb, which maintains a certain brightness even after 50 min. Hence, this work provides a new and efficient route for synthesizing carbon-based NiCo2O4/NiCo-LDH composites for use as advanced energy storage materials.

Reactive Species Risk Assessment Using Optimized HET-CAM Safety Evaluation of Feed Gas-Modified Gas Plasma Technology and Anticancer Drugs.

Clinical therapies, including dermatology and oncology, require safe application. In vitro experiments allow only limited conclusions about in vivo effects, while animal studies in, e.g., rodents have ethical constraints at a large scale. Chicken embryos lack pain reception until day 15 postfertilization, making the in ovo model a suitable alternative to in vivo safety assessment. In addition, the hen's egg test on chorioallantoic membrane assay allows irritation potential analysis for topical treatments, but standardized analysis has been limited so far. Medical gas plasma is a topical, routine, approved dermatology treatment. Recent work suggests the potential of this technology in oncology. Its main mode of action is the release of various reactive species simultaneously. Intriguingly, varying plasma feed gas compositions generates customized reactive species profiles previously shown to be optimized for specific applications, such as skin cancer treatment. To support clinical implications, we developed a novel chicken embryo CAM scoring and study scheme and employed the model to analyze 16 different plasma feed gas settings generated by the atmospheric pressure plasmajet kINPen, along with common anticancer drugs (e.g., cisplatin) and physiological mediators (e.g., VEGF). Extensive gas- and liquid-phase plasma reactive species profiling was done and was found to have a surprisingly low correlation with irritation potential parameters. Despite markedly different reactive species patterns, feed gas-modulated kINPen plasma was equally tolerated compared to standard argon plasma. CAM irritation with gas plasmas but not anticancer agents was reversed 48 h after treatment, underlining the only temporary tissue effects of medical gas plasma. Our results indicate a safe therapeutic application of reactive species.

Gold nanoparticles with natural polymer synthesized by plasma–liquid interactions: Size-control, characterization and colorimetric detection of melamine based on the size effect of gold nanoparticles

This work reports the synthesis of size-controlled gold nanoparticles as AuNP colloids in aqueous solutions with capping natural polymer matrices – the sodium salt of carboxymethyl cellulose, using a liquid-phase plasma process. The effects of the solution plasma process discharge time, concentrations of gold(III) chloride trihydrate precursor (0.06–2.5 mmol/L) and correlations of the precursor/CMC ratios on the characteristics on the synthesized Au NPs, including size distribution and optical absorption properties, were investigated. The average size (20–90 nm) and form (spherical, hexagonal and triangular) of the AuNPs can be change depending on the initial concentration of Au3+ and the ratios of precursor/CMC on the process synthesis. Gold nanoparticles were used to study a straightforward colorimetric detection of melamine. Melamine caused the AuNPs to agglomerate in aqueous solution, changing their visible color from red to blue. The prepared AuNPs can be used for the detection of melamine with a low LOD and an extremely wide linear range (0.005–0.21 μM.).

Decomposition of the antibiotic sulfamethoxazole by the liquid-phase plasma process enhanced by peroxymonosulfate

In this study, sulfamethoxazole (SMZ) was successfully degraded using the liquid phase plasma (LPP) method, a new advanced oxidation process (AOPs). The effects of LPP process variables and side reactions on SMZ decomposition reactions were evaluated, and optimal LPP process conditions were determined based on these data. To increase the efficiency of the SMZ decomposition reaction, peroxymonosulfate (PMS) was added to the LPP reaction. The optimal addition amount was derived by tracking the change in the amount of oxidation radicals produced according to the addition of PMS. By analyzing the reaction intermediates generated in the SMZ decomposition reaction, the decomposition pathway of SMZ by the LPP method was proposed.

(Invited) Mechanism of H2 Synthesis Due to Plasma-Induced Water Splitting Via Free-Electron Impact

The electrified plasma-liquid interface (EPLI) has two major local reactors, the plasma phase and the liquid phase. Both local reactors enable water splitting, but their synthesis mechanism is different. While the mechanism of H2 synthesis in a liquid phase (plasma electrochemistry) was reasonably deciphered, the respective mechanism in the plasma phase does not (plasma chemistry). In this present contribution, the Chemical Reaction Network (CRN) analysis serves as a tool to decipher the H2 synthesis mechanism in the plasma reactor. For that, the datum from the laboratory of Sankaran serves as grounds for the CNR analysis. Sankaran team identified that the equilibrium vapor pressure of water introduces water vapor in the plasma phase; and that, fundamentally, there were eight elementary reactions involved in the plasma-chemistry mechanism of H2 synthesis, i.e., those reactions containing the largest constant rates (or electron rate coefficients). [1] The authors obtained the reaction rate constants via a numerical solution of the Boltzmann equation (BE) for electrons in weakly ionized gases considering the uniform electrical field. [2] Together, those eight elementary reactions form the following global reaction for the water splitting via electron-impact8 H2O → ●H+ ●OH + ●O + O– + O+ + OH– + OH+ + H– + H+ that is also rationalized in terms of global CRN, shown in figure 1. The water molecule splits into two major classes of fragments, the radical fragment set {●H, ●OH and ●O} and the ionic fragment set {O–, O+, OH–, OH+, H–, H+}. These two classes of fragments receive different treatments in this work because their kinetic relaxation is supposed to follow different time scales. The radical fragment is supposed to relax toward final products much faster than the ionic fragments. For this reason, only the chemical dynamics of the radical fragment are considered in the relaxation step toward the final products. The chemical dynamics of relaxation toward final products, thus, take into account only the set of radical fragments. This talk will present and discuss the chemical reaction network (CRN) for the relaxation of the radical fragment toward final products like hydrogen (H2), hydrogen peroxide (H2O2), water (H2O), and eventually oxygen (O2). The radical-relaxation CNR is not shown in this abstract but will be present/discussed in the talk.Roughly speaking, the radical-relaxation dynamics must deliver hydrogen as the major product and hydrogen peroxide as the major side-product, besides a stochiometric ratio of 4 to 1, respectively. Specifics on whether the radicals •OH relaxes toward H2O2 or H2O depend on the local dynamics, meaning that it mostly relies on the parameter set values that drive the CRN. Unfortunately, there is no experimental evidence already reporting the stoichiometry of products, which makes it unfeasible to evaluate the adherence of our analysis to the experimental pieces of evidence.

Evaluation of carbon black produced with hydrogen by the liquid phase plasma method as a conductive material for the anode of a supercapacitor

Carbon black is produced with H2 gas from a benzene solution using the liquid-phase precipitation (LPP) mathod. Subsequently, the carbon black is heat-treated and applied as a conductive material for a supercapacitor to evaluate its performance. Carbon black produced as primary particles by the LPP reaction aggregates and grows into a secondary structure, and then crystallizes through heat treatment to form multi-polygonal nanoshells. The electrical conductivity of carbon black increased by heat treatment, but when the temperature exceeded 1500 °C, the electrical conductivity rather decreased. Following heat treatment at 1500 °C, the electrode used as the conductive material exhibits the largest specific capacitance value and the smallest IR drop. As the carbon black produced via the LPP method exhibits better conductive properties than those of Super-P, the potential to use the present method as a new hydrogen production method is confirmed.

Enhanced hydrogen production from cracking of liquid toluene by applying liquid plasma and perovskite catalysts

In this study, a process for producing hydrogen from liquid hydrocarbons by applying plasma is proposed. Toluene was decomposed by discharging a pulse-type plasma into liquid toluene directly. The changes in the rate of hydrogen production and reaction characteristics owing to injecting a perovskite catalyst were also investigated. A high hydrogen production rate of approximately 130 NL/h·g was obtained from the liquid–phase plasma reaction of toluene using the BiFeO3 catalyst. The investigation into the reaction characteristics based on the plasma generation conditions indicated that the reaction was mainly affected by the plasma voltage. When titanium dioxide and perovskite (SrTiO3, BiFeO3) photocatalysts were applied to this reaction, the reaction activities also varied depending on the light-absorption capacity of the catalysts. The highest hydrogen evolution rate was obtained using the BiFeO3 catalyst, which absorbs visible light as well as UV light, compared with the TiO2 photocatalyst, which absorbs only UV light. Because the plasma emission from toluene is predominantly in the visible region, the reaction activity was also determined to be the highest for the BiFeO3 catalyst. The BiFeO3 absorbs visible light up to about 550 nm, and it has a small bandgap energy of about 2.15 eV. This led to high photocatalytic degradation activity in visible light generated by plasma discharge in toluene. The carbon obtained had a particle size of less than 20 nm and purity of approximately 99%.

Liquid phase plasma for in-situ hydrogenation of heavy oil model compound (n-hexadecane)

Hydrogenation is an effective way to improve the efficiency of heavy oil utilization. In order to fully make interactions between active species such as hydrogen radicals with heavy oil, an innovative heavy oil upgrading method for in-situ hydrogenation by liquid phase discharge with non-uniform electric field was applied. In this work, experiments on discharge frequency and single discharge energy were made to discuss the calorific value in n-hexadecane (a heavy oil model compound). It was found that when the single discharge energy was in the range of 2.22–6.18 mJ, the calorific value gradually increased as the single discharge energy increased. The result also showed that when the discharge frequency reached 1.7 kHz, the hydrogenation performance was significantly better. In addition, the calorific value in conversion part increased by 10.16% when the discharge time reached 30 s compared to the original, which further provide sufficient evidence for the fast in-situ plasma-enabled hydrogenation.

Current Progress on Methods and Technologies for Catalytic Methane Activation at Low Temperatures.

Methane (CH4 ) is an attractive energy source and important greenhouse gas. Therefore, from the economic and environmental point of view, scientists are working hard to activate and convert CH4 into various products or less harmful gas at low-temperature. Although the inert nature of CH bonds requires high dissociation energy at high temperatures, the efforts of researchers have demonstrated the feasibility of catalysts to activate CH4 at low temperatures. In this review, the efficient catalysts designed to reduce the CH4 oxidation temperature and improve conversion efficiencies are described. First, noble metals and transition metal-based catalysts are summarized for activating CH4 in temperatures ranging from 50 to 500°C. After that, the partial oxidation of CH4 at relatively low temperatures, including thermocatalysis in the liquid phase, photocatalysis, electrocatalysis, and nonthermal plasma technologies, is briefly discussed. Finally, the challenges and perspectives are presented to provide a systematic guideline for designing and synthesizing the highly efficient catalysts in the complete/partial oxidation of CH4 at low temperatures.

A facile and efficient approach for the removal of high concentrations of ammonia nitrogen in wastewater: Liquid-phase plasma treatment

We report the facile and effective liquid-phase plasma treatment (LPPT) approach for removing high concentrations of ammonia nitrogen from wastewater. The effects of the operating parameters, including the pH and temperature, the pulse repetition frequency, the pulse duration, and the reaction time, were investigated to obtain the optimal removal conditions using a simulated wastewater sample. It was found that a higher pulse repetition, a longer pulse duration, and alkaline conditions were favorable for the removal of ammonia nitrogen. Thus, at pH 12, a pulse repetition frequency of 30 kHz, and a pulse duration of 3.0 μs, the removal efficiency of ammonia nitrogen reached 100% in 25 min during the LPPT. In addition, when isopropanol (IPA) and 1, 4-diazabicyclooctane triethylenediamine (DABCO) were used as scavengers for ∙OH and 1O2, respectively, the removal efficiency of ammonia nitrogen after 25 min decreased from 71.7% to 68.1% in the presence of DABCO and from 71.7% to 62.8% in the presence of IPA. Based on these results, the mechanism of ammonia nitrogen removal was proposed to constitute the collision of accelerated electrons and the oxidation reaction of ∙OH. Moreover, it was confirmed that the LPPT approach was feasible for the removal of ammonia nitrogen from wastewater.

Remediation of water contaminated with polycyclic aromatic hydrocarbons using liquid phase plasma: Influence of electrical discharge condition

Although the number of vessels with exhaust gas cleaning systems (EGCSs or scrubbers) has sharply increased to comply with strengthened regulations for marine environment, secondary pollutions are caused by discharged polycyclic aromatic hydrocarbons (PAHs) from scrubber effluent. Here, liquid-phase plasma (LPP) is employed to remediate water contaminated with PAHs. The increased frequency and pulse width enhanced the degradation efficiency, and 93.3, 90.7, 86.0, and 85.4% for naphthalene (Nap), acenaphthene (Ace), fluorene (Flu), and phenanthrene (Phe), respectively, are degraded at a frequency of 30 kHz and pulse width of 3 μs in 10 min. Considering physical condition of the plasma, long pulse width accelerated electrons, leading to increased generation of active species from intensified collision between electrons and surrounding molecules. Conversely, high frequency decelerated electrons due to the excessive changes in the polarity. However, the increased number of plasma discharges results in the generation of numerous active species. Generations of •OH and O radicals are confirmed by optical emission spectrometry and electron paramagnetic resonance. In addition, changes in functional groups which are corresponding to hydroxyl and oxygen groups are identified by Fourier transform infrared spectroscopy. Total PAHs in real scrubber are reduced from 1.1 to 0.4 μgL-1 with degradation efficiency of 63.6% after 10 min of LPP treatment. This study suggests LPP can be a promising method to protect diverse aqueous environments and provides optimal electrical discharge condition for degradation of organic pollutants.

Fabrication of Ni/TiO2 visible light responsive photocatalyst for decomposition of oxytetracycline

Nickel-impregnated TiO2 photocatalyst (NiTP) responding to visible light was prepared by the liquid phase plasma (LPP) method, and its photoactivity was evaluated in degrading an antibiotic (oxytetracycline, OTC). For preparing the photocatalyst, nickel was uniformly impregnated onto TiO2 (P-25) powder, and the nickel content increased as the number of LPP reactions increased. In addition, the morphology and lattice of NiTP were observed through various instrumental analyses, and it was confirmed that NiO-type nanoparticles were impregnated in NiTP. Fundamentally, as the amount of impregnated nickel in the TiO2 powder increased sufficiently, the band gap energy of TiO2 decreased, and eventually, the NiTP excited by visible light was synthesized. Further, OTC had a decomposition reaction pathway in which active radicals generated in OTC photocatalytic reaction under NiTP were finally mineralized through reactions such as decarboxamidation, hydration, deamination, demethylation, and dehydroxylation. In effect, we succeeded in synthesizing a photocatalyst useable under visible light by performing only the LPP single process and developed a new advanced oxidation process (AOP) that can remove toxic antibiotics.

A Review on the Recent Breakthrough Methods and Influential Parameters in the Biodiesel Synthesis and Purification

Biodiesel has recently received much attention as an energy source with numerous benefits such as high degradability, negligible toxicity, and minimal emissions of carbon monoxide gases as well as particulates. Therefore, this research aims to compare, review, and summarize the conventional and advanced methods of biodiesel production. Currently, some emerging processes that were developed for advanced biodiesel production include microwave-assisted synthesis, ultrasonic-assisted synthesis, supercritical transesterification, and liquid phase plasma discharge technology. The types of feedstocks, catalysts, and operating conditions as the influential parameters in biodiesel synthesis are also discussed. Moreover, in the purification process, the effectiveness of purification depends on the type of catalyst applied in the synthesis process. This research also reviewed and compared several commonly used purification methods such as wet and dry washing, ion exchange and precipitation, complexation, and membrane-based separation that have shown significant results along with the impacts of biodiesel production on environmental and economic sectors

Application of liquid-phase plasma for the production of hydrogen and carbon from the plasma-induced cracking of liquid hydrocarbons

A study was conducted on the decomposition reaction of liquid hydrocarbons induced by liquid plasma and photocatalyst. This study is to obtain useful resources by recycling waste liquid-hydrocarbons. Titanium dioxide and TiO2-doped with a metal (and nitrogen atoms) were used as photocatalysts individually in the study. First, H2 and carbon were simultaneously produced in the decomposition reaction of liquid hexane and benzene induced by liquid plasma. Notably, only H2 was obtained as a gaseous product, and no carbon dioxide was produced in this reaction. However, when photocatalyst was injected into this decomposition, the corresponding reactivity improved. In particular, the amount of H2 and carbon produced increased in the order of: the amount of H2 and carbon produced with N/Ni/TiO2 > Ni/TiO2 > TiO2 photocatalyst, respectively, when the photocatalyst was added in an equal amount to the reactant of the decomposition. The highest carbon yield and hydrogen evolution under these experimental conditions were about 1 %/(g∙h) and about 180 L/(g∙h), respectively. This order is because the strong visible light generated by liquid plasma discharge improved the photoreactivity of the N/Ni/TiO2 photocatalyst that has a high sensitivity to visible light and narrow band gap. Carbon particles produced from the decomposition reaction of liquid hexane and benzene, respectively, induced by liquid plasma and photocatalyst were small and uniform, with a size of 10 nm or less. In addition, the BET surface area of the carbon produced in this reaction was greater than 500 m2/g, and the properties of the carbon particles were almost the same regardless of the lapse of reaction time. Hence, this decomposition reaction of liquid hexane and benzene, respectively, induced by liquid plasma and photocatalyst was judged to be forming an efficient technology that can simultaneously obtain high-purity hydrogen energy and useful basic materials from liquid hydrocarbons.

Facile synthesis of reduced graphene oxide@Co3O4 composites derived from assisted liquid-phase plasma electrolysis for high-performance hybrid supercapacitors

Reduced graphene oxide@Co3O4 (rGO@Co3O4) composites are widely developed as promising electrode materials; however, their practical applications are restricted owing to their complex synthesis process. In the current work, we developed a rapid, efficient, and facile method for the one-step synthesis of rGO@Co3O4 composites via assisted liquid-phase plasma electrolysis. During the plasma electrolysis process, uniform and ultrafine Co3O4 particles are grown in-situ on rGO. The rGO@Co3O4 composites present a specific capacitance as high as 1249.0F/g at 1 A/g and a capacitance retention of 89.7 % over 10,000 cycles in a three-electrode system. The superior electrochemical performance is ascribed to the synergistic effect of the high specific capacitance Co3O4 and highly conductive rGO, which is conducive to promoting the transportation efficiency of ions/electrons and reducing the volume change of Co3O4 in the charge–discharge cycle. Asymmetric supercapacitors are also assembled using rGO@Co3O4 composites as the positive electrode and rGO as the negative electrode. The asymmetric supercapacitors achieve a specific capacitance of 72.3F/g at 1 A/g, display an energy density of 23.6 Wh/kg at a power density of 0.4 kW/kg, and exhibit superior cycle stability with a capacitance retention of 88.2 % over 10,000 cycles at 5 A/g. The current work provides a rapid, efficient, and facile method for the one-step synthesis of rGO-transition metal oxide electrodes as advanced energy storage devices.

Extracellular vesicles present in bone, blood and extracellular matrix have distinctive characteristics and biologic roles

IntroductionExtracellular vesicles (EV) have long been recognized as an important means of cell to cell communication, but current metrics to delineate various subpopulations of EV are limited. Recently, a distinctive subpopulation of EV embedded within the extracellular matrix of soft tissues, termed matrix-bound nanovesicles (MBV), has been described. Although the lipid membrane composition and intravesicular cargo of MBV clearly differ from liquid phase EV (i.e. exosomes), a more comprehensive characterization of the physical and biologic properties of MBV vs. exosomes and those of a separate subpopulation of EV, specifically bone matrix vesicles, would contribute to our understanding of the biogenesis and physiologic role of these three EV subpopulations. ResultsThe physical characteristics, protein and miRNA cargo profiling, vesicle membrane lipidomics, and immunomodulatory activity were used to compare skeletal muscle-derived MBV, liquid phase plasma exosomes, and mineralization-competent matrix vesicles of provisional bone matrix. We show that despite similar physical characteristics, these three preparations of EV represent distinct entities with different biologic activity. ConclusionThese results inform metrics for the categorization of EV and provide tools for the isolation of EV for potential diagnostic and therapeutic applications.