Silicate Ions Research Articles

Comparative Carbon Synthesis of Peat using ZnCl2 and H3PO4 for Heavy Metal Adsorption in Oilfield Produced Water

Oilfield Produced Water is one of the amplest wastes resulting from oil and gas operations and it’s of great industrial concern due to its quantity, concentration, and cost of treatment; thus, it needs cheaper and more available options. Peat being an option is a renewable brown deposit resembling soil, formed as a result of an accumulation of organic matter, also known to have a rich carbon content. This research work aims to comparatively synthesize peat soil with ZnCl2 and H3PO4, carbonize, characterize, and determine the efficiency of heavy metal adsorption in Oilfield Produced Water. The peat samples were collected from Warri City commonly referred to as Oil City in southern Nigeria and were impregnated with ZnCl2 (PAC-ZC); H3PO4 (PAC-HP); ZnCl2 and H3PO4 at a ratio of 1:1 (PAC-ZC+HP) and with De-ionized water as control (PAC-D). After activation, peat was carbonized at 400oC for 1 hour. Fourier-Transform Infrared Spectroscopy analysis showed all five samples have a strong silicate ion peak between 998.9 - 1028.7cm-1, the presence of Vincy C-H group at 909.5cm-1, broad shaped polar O-H bond between 369.5 – 3623.0cm-1 and an adsorption peak between 2929.7 – 2012.8cm-1 which disappeared after activation and carbonization. Scanning Electron Microscopy micrograph shows a surface enhancement after activation and carbonization. The heavy metals (Pb, Cu, Ni, Zn & Fe) level in the Oilfield Produced Water was analyzed before and after treatment with Peat Activated Carbon using Atomic Absorption Spectrometry. Four dosages (1,2,3, and 4g) of each Peat Activated Carbon were used to treat 100ml of Oilfield Produced Water. PAC-ZC and PAC-ZC+HP showed 100% efficiency in the removal of turbidity, Pb, Cu, Ni, and Fe. However, the overall efficiency trend of the adsorption capacity of the Peat Activated Carbon was PAC-ZC > PAC-ZC+HP > PAC-HP > PAC-D. With the experimental result, PAC-ZC and PAC-ZC+HP can be used as treatment options for Oilfield Produced Water.

Solubility of 15MgO–15CaO–5P2O5–10SiO2 glass

AbstractMg2+ and silicate ions are important ionic species in bone formation. Previously, the authors’ group reported a 15MgO–15CaO–8P2O5–4SiO2 glass (silicophosphate invert glass [spIG]) containing orthophosphate and orthosilicate structures. Mg2+ and Ca2+ ions in the glass preferentially formed Si–O–Mg and P–O–Ca bonds, respectively, suppressing the release amount of silicate ions in a tris–HCl buffer solution (TBS). In this study, a new 15MgO–15CaO–5P2O5–10SiO2 invert glass without a silicate 3D‐network structure was prepared via a melt‐quenching method. The new glass exhibits an improved silicate‐ion release ability that promotes bone formation. The dissolution amounts of Ca2+ and phosphate ions from the glass into a TBS were similar to those of spIG, but the amounts of Mg2+ and silicate ions increased by ∼2 and ∼5 times, respectively. 31P and 29Si magic‐angle spinning nuclear magnetic resonance spectroscopic analyses showed that the glass was composed of orthophosphate and chain silicate structures. Even when the silica content exceeded that of spIG, the formation of a silicate 3D‐network was suppressed. The O1s X‐ray photoelectron spectra indicated that (Si, P)–O–Mg bonds contribute to the glass formation. In a glass model based on classical molecular dynamics, the oxygen coordination numbers of Mg and Ca were determined as 4–7 and 5–8, respectively. Mg2+ ions are predominantly responsible for bridging the silicate/phosphate structures in this glass and play an important role in tuning the glass formation and the release amount of silicate ions.

Microporous Hydroxyapatite-Based Ceramics Alter the Physiology of Endothelial Cells through Physical and Chemical Cues.

Incorporation of silicate ions in calcium phosphate ceramics (CPC) and modification of their multiscale architecture are two strategies for improving the vascularization of scaffolds for bone regenerative medicine. The response of endothelial cells, actors for vascularization, to the chemical and physical cues of biomaterial surfaces is little documented, although essential. We aimed to characterize in vitro the response of an endothelial cell line, C166, cultivated on the surface CPCs varying either in terms of their chemistry (pure versus silicon-doped HA) or their microstructure (dense versus microporous). Adhesion, metabolic activity, and proliferation were significantly altered on microporous ceramics, but the secretion of the pro-angiogenic VEGF-A increased from 262 to 386 pg/mL on porous compared to dense silicon-doped HA ceramics after 168 h. A tubulogenesis assay was set up directly on the ceramics. Two configurations were designed for discriminating the influence of the chemistry from that of the surface physical properties. The formation of tubule-like structures was qualitatively more frequent on dense ceramics. Microporous ceramics induced calcium depletion in the culture medium (from 2 down to 0.5 mmol/L), which is deleterious for C166. Importantly, this effect might be associated with the in vitro static cell culture. No influence of silicon doping of HA on C166 behavior was detected.

Dimeric and oligomeric interactions between calcium silicate aqua monomers before calcium silicate hydrate nucleation

Understanding the formation mechanism of calcium silicate hydrate (C-S-H) is pivotal to control the kinetics of calcium silicates hydration and the evolution of C-S-H microstructure. However, the reactions between calcium- and silicate-based aqueous species before or during the process of C-S-H nucleation at molecular level are still unclear. Here, based on ab initio metadynamics simulations, we find that the dimeric interaction between calcium silicate aqua monomers leads to the formation of a calcium silicate aqua Q0-dimer through an ionic bond between calcium and silicate ions and a reduction of hydration number of the Ca ion, which is prior to the formation of silicate dimers (Q1). Besides, the first coordination shell of the Ca ion in the most stable calcium silicate aqua cluster has the characteristics of both tobermorite and jennite structures. We further propose a potential formation pathway for C-S-H, where the replacement of water ligands of the Ca ion by silicates initiates the clustering and dimerization of silicate monomers and promotes the formation of C-S-H.

Structural organization of phase-separated bioactive glasses and the clustering of Si, P, B, Na and F atoms investigated by solid-state NMR and Monte Carlo simulations

In this paper we studied the effect of NaBO2 addition to a phase-separated alkali-free bioactive glass with a composition of 38.49 SiO2 • 36.07 CaO • 19.24 MgO • 5.61 P2O5 • 0.59 CaF2. Microscopy reveals binodal phase separation involving two Si-containing microphases with a droplet size of ∼200 μm, driven by the thermodynamic LLPS mechanism. The local environments and spatial distribution of silicate, phosphate, and fluoride ions in this phase-separated system were studied, using 29Si, 31P, 11B, 19F, 25Mg, and 23Na nuclear magnetic resonance (NMR) and infrared spectroscopy. The silicate units are dominantly of the metasilicate (Si2) type. The phosphate units exist mostly as orthophosphate (P0) while the borate is present in the form of pyroborate (B1). Multinuclear dipolar re-coupling experiments indicate that the minority components F, P, B and Na all occur within a common phase. Thus, atomic distribution scenarios involving the separation of these components into separate phases can be excluded. The 31P spin echo decay (SED) method was used along with Monte Carlo simulations to characterize the spatial distribution of the phosphate component. Based on the analysis, the phosphate component forms clusters of sizes 1-4 nm, which are embedded in an environment more dilute in phosphate, having a random distribution. While 19F SED results indicate that the fluoride ions do not form clusters and are close to randomly distributed, dipolar recoupling of 31P suggests a local environment resembling that of fluorapatite.

Resistance of Sugarcane Clones (Saccharum spp.) to Red Rot Disease (Collectorichum falcatum Went) and Analysis of Resistant clone by FTIR

Sugarcane (Saccharum spp.) is an important industrial crop and mainly grown for the sugar and jaggery production. The major constraint in the sugarcane cultivation is the outbreak of red rot disease and many high yielding and high sugar varieties succumb to the disease-causing huge reduction in the cane yield and also quality of cane. The disease is very difficult to manage as the pathogen is deep seated in the stalk. Exploitation of the host resistance in viable way to contain the disease. The sugarcane clones developed were screened for resistance to red rot disease by artificial inoculation. Among the 52 clones screened three clones viz., C15632, 16G032 and 16G031 behaved resistant and thirteen clones C15004, C15006, C15011, C15021, C15095, C15157, C15559, C15603, 16G006, 16G087, 16G046, 15G060 and 15G028 behaved moderately resistant to red rot. In the FT-IR analysis of the leaf samples of resistant type clones spectral peaks were found in wave length of 1046 cm-1, 1044 cm-1 and 1068 cm-1 associate with the functional group of the molecule Aliphatic fluoro compound, C-F stretch / Primary alcohol, C-O Stretch / Primary amine, CN stretch / Phosphate / Silicate ions and these functional group of components may be associated for the resistance to the red rot.

Investigation of performance and mechanism of zinc removal from polluted water by concrete fines derived from aggregate recycling: From problematic byproducts to effective adsorbent

Concrete fines are byproducts produced from aggregate recycling. Because of their properties, they cannot be directly recycled for use in concrete manufacturing, which is problematic to move the cement and concrete industry toward sustainable development goals and reduce its environmental impact. Taking advantage of concrete fines unique properties was regarded as a possible research direction. The hydrated cement fraction was expected to provide alkalinity to neutralize the acidic solutions, while calcium related compounds were expected to provide the function of heavy metals removal. In this research, concrete fines were used to remove Zn from acid mine drainage as an active treatment. The removal performance was comprehensively investigated. The maximum capacity of Zn-adsorption is 111.9 mg/g, and almost 100% Zn can be removed for an initial Zn concentration of 20 mg/L. The dominant reaction mechanism of Zn adsorption to concrete fines was determined to be ion-exchange reaction with surface complexation and precipitation. The Zn2+ ions in solution can exchange with the Ca2+ ions in calcium silicates and calcium silicate hydrates in concrete fines and replace the protons released by ionization of the silanol group for complexation, and thus Zn removal is not limited to an alkaline environment or high initial Zn concentration. The acidity was alkalized by hydration reaction, mainly consuming calcium hydroxide. Based on these mechanisms, concrete fines are effective adsorbent to remove Zn without the need for the synergistic reactions of other metals and for making the aqueous solution strongly alkaline, even in the strongly acidic environments and in effluents with high Zn concentration. Through evaluation and comparison of Zn adsorption capacity with other materials, concrete fines were regarded as promising alternative adsorbent for Zn removal.

Silicate ions as soluble form of bioactive ceramics alleviate aortic aneurysm and dissection.

Aortic aneurysm and dissection (AAD) are leading causes of death in the elderly. Recent studies have demonstrated that silicate ions can manipulate multiple cells, especially vascular-related cells. We demonstrated in this study that silicate ions as soluble form of bioactive ceramics effectively alleviated aortic aneurysm and dissection in both Ang II and β-BAPN induced AAD models. Different from the single targeting therapeutic drug approaches, the bioactive ceramic derived approach attributes to the effect of bioactive silicate ions on the inhibition of the AAD progression through regulating the local vascular microenvironment of aorta systematically in a multi-functional way. The in vitro experiments revealed that silicate ions did not only alleviate senescence and inflammation of the mouse aortic endothelial cells, enhance M2 polarization of mouse bone marrow-derived macrophages, and reduce apoptosis of mouse aortic smooth muscle cells, but also regulate their interactions. The in vivo studies further confirm that silicate ions could effectively alleviate senescence, inflammation, and cell apoptosis of aortas, accomplished with reduced aortic dilation, collagen deposition, and elastin laminae degradation. This bioactive ceramic derived therapy provides a potential new treatment strategy in attenuating AAD progression.

Synthesis of Tetraethoxysilane-Reacted Hydroxyapatite Nanoparticles and Their Stabilization in Phosphate-Buffered Saline.

Hydroxyapatite (HA) particle, which is an inorganic component of biological hard tissues, is being applied as a bioceramic for biotechnology and medicine fields. However, early bone formation is difficult in the implantation of well-known stoichiometric HA into our body. To solve this problem, it is important to control the shapes and chemical compositions of the physicochemical properties of HA to be functionalized as the state similar to the biogenic bone. In this study, the physicochemical properties of the HA particles synthesized in the presence of tetraethoxysilane (TEOS) (SiHA particles) were evaluated and investigated. In particular, the surface layers of the SiHA particles were successfully controlled by adding silicate and carbonate ions in the synthetic, which would be involved in the bone formation process, and their elusive reaction behavior with phosphate-buffered saline (PBS) was also evaluated. The results showed that the ions in the SiHA particles increased with the increase in the added TEOS concentration, and the silica oligomer was also formed on the surfaces. The ions were present not only in the HA structures but also on the surface layers, indicating the formation of the non-apatitic layer containing the hydrated phosphate and calcium ions. The change in state of the particles with the immersion in PBS was evaluated, the carbonate ions eluted from the surface layer into PBS, and the free water component in the hydration layer increased with the immersion time in PBS. Therefore, we successfully synthesized the HA particles containing silicate and carbonate ions, suggesting the important state of the surface layer consisting of the characteristic non-apatitic layers. It was found that the ions in the surface layers can react with PBS and leach out, weakening the interaction of hydrated water molecules on the particle surfaces to increase the free water component in the surface layer.

Hydrogeochemical processes and groundwater evolution of the São Sebastião-Marizal aquifer system in the Tucano Central Basin, Bahia, Brazil

• New hydrogeochemical and physicochemical data for 35 samples of the São Sebastião-Marizal Aquifer System. • Ca–Na–Mg–HCO 3 –Cl facies of recharge zones evolves to Mg–Ca–Cl and Na–Cl facies along groundwater flow in the Marizal and São Sebastião aquifers, respectively. • Silicate weathering exerts a dominant control on groundwater composition. • Water-rock interaction is the main hydrogeochemical process. • Physicochemical parameters are more variable within the unconfined Marizal aquifer. • Alkaline to alkaline earth ratios indicate that reverse ion exchange predominates in the Marizal aquifer. • The hydrogeochemical signature indicates that silicate weathering and ion exchange processes contribute equally in the São Sebastião aquifer.

Geochemical evaluation of groundwater around Chromepet tannery belt, Southern India

The study appraises the geogenic and anthropogenic contamination of groundwater around tanneries located in Chromepet, Southern India. Thirty-six groundwater samples were examined for major anions, cations and trace metals concentration. The concentration of chromium (Cr), iron (Fe) and lead (Pb) in the study area ranges from 0.04 to 0.51 mg/L, 0.001–1.07 mg/L and 0.001–0.09 mg/L respectively. 97% of the samples exceeded the acceptable range for Cr whereas, lead and iron exceeded 89 and 8% of the samples respectively. The high concentrations of chromium, iron and lead in the groundwater are due to the influence of tannery effluents. The majority of the samples in the study area suggested silicate weathering. The piper plot reveals that 50% of the water samples have Na–Cl type water which is possibly due to anthropogenic sources. The Chadha plot revealed that silicate weathering and ion exchange govern the bulk of groundwater chemistry in freshwater aquifers owing to carbonate precipitation and mineral dissolution. Durov plot highlights that the bulk of the samples has no dominating anion or cation types, indicating simple dissolution or mixing. Saturation Index (SI) reveals that 50% of the samples were supersaturated due to calcite and dolomite precipitation. Principal Component Analysis (PCA) 1 suggested secondary salt discharge from geogenic and anthropogenic processes due to tanning industries. Increasing the performance of wastewater treatment plants is essential to improve the groundwater quality of the region under tannery influence.

Synthesis of Hydroxyapatite Containing Different Ions and Control of Their Surface Layers

In this review, the current status and issues of bone defect sites in our body were explained based on the examples of the conventional hydroxyapatite (HA), and the necessity of regenerative functions in addition to bone defect sites for the biomedical applications was proposed. The characteristics and properties of HA substituted with the heterogeneous ions such as silicate, carbonate and other elemental ions were explained. For the effective control of the biomedical function, the characteristics and possibilities of the surface layer formed on HA and its components, the hydrated layer and the non-HA layer were proposed, and their relationship for improving the biocompatibility was highlighted.

Thermal Stability of Iron- and Silicon-Substituted Hydroxyapatite Prepared by Mechanochemical Method

In this study, hydroxyapatite with the substitution of calcium cations by iron and phosphate by silicate groups was synthesized via a mechanochemical method. The as-prepared compounds have the general formula Ca10−xFex(PO4)6−x(SiO4)x(OH)2−xOx/2 with x = 0–1.5. The thermal stability of the as-prepared compounds was studied by ex situ annealing of powders in a furnace. It has been established that, at 800 °C for x ≤ 0.5, a partial decomposition of the substituted apatites occurs with the formation of the β–Ca3(PO4)2 phase. At high “x” values, the formation of this phase starts at the lower temperature of 700 °C, followed by the formation of Fe2O3 at 900 °C. The introduction of iron and silicate ions into the hydroxyapatite lattice was shown to decrease its thermal stability.

Investigation of Surface Layers on Biological and Synthetic Hydroxyapatites Based on Bone Mineralization Process.

In this review, the current status of the influence of added ions (i.e., SiO44-, CO32-, etc.) and surface states (i.e., hydrated and non-apatite layers) on the biocompatibility nature of hydroxyapatite (HA, Ca10(PO4)6(OH)2) is discussed. It is well known that HA is a type of calcium phosphate with high biocompatibility that is present in biological hard tissues such as bones and enamel. This biomedical material has been extensively studied due to its osteogenic properties. The chemical composition and crystalline structure of HA change depending on the synthetic method and the addition of other ions, thereby affecting the surface properties related to biocompatibility. This review illustrates the structural and surface properties of HA substituted with ions such as silicate, carbonate, and other elemental ions. The importance of the surface characteristics of HA and its components, the hydration layers, and the non-apatite layers for the effective control of biomedical function, as well as their relationship at the interface to improve biocompatibility, has been highlighted. Since the interfacial properties will affect protein adsorption and cell adhesion, the analysis of their properties may provide ideas for effective bone formation and regeneration mechanisms.

The impact of metakaolin on the hydration of tricalcium silicate: effect of C-A-S-H precipitation

Introduction:Metakaolin (MK) is used as supplementary cementitious material to reduce the CO2footprint of Portland cements. However, the early hydration of Portland cement (OPC) is often retarded due to its use. The present work investigates the mechanisms of this retardation. Focus is laid on the interaction of MK with the main clinker phase C3S (Ca3SiO5, pure form of alite) that is known to govern the kinetics of early hydration of OPC.Methods:Hydration reactions of MK and C3S were analysed by optical emission spectroscopy, electron microscopy, thermal analysis, X-ray diffraction and reaction calorimetry.Results:Results on MK showed that compared to sodium ions the presence of calcium ions reduced the maximum amounts of silicate and aluminate ions released into solution by MK. For MK + C3S mixtures, C-A-S-H was formed at the surfaces of both C3S and MK within minutes with a composition of (CaO)1.3(SiO2)0.8(Al2O3)0.2(H2O)2.7. The solubility constant of (CaO)1.3(SiO2)0.8(Al2O3)0.2(H2O)2.7was determined.Discussion:C-A-S-H appeared to be an unsuitable substrate for C-S-H nucleation. Therefore, its formation during early hydration is expected to play an important role in the retardation of C3S hydration. Indeed, when C-A-S-H seeds are formed, less C-S-H seeds are formed leading to lengthen the duration of the induction period. The presence of sulfate ions reduces the amount of C-A-S-H seeds as most aluminate ions are consumed to form ettringite. Consequently, sulfate ions induce an increase of the hydration kinetics such as observed in MK + C3S mixtures.

Study of some physical and chemical properties of the southern part of Al-Hawizeh Marsh/ Southern of Iraq

Some physical and chemical properties of the water quality at the Al-Hawizeh Marsh Southern of Iraq were studied seasonally during the period from October 2020 to July 2021 at four stations. The studied factors included air and water temperature, pH, transparency, water salinity, electrical conductivity, dissolved oxygen, biological oxygen demand, nitrate, phosphate, silicate, and chloride ion. The results of the current study showed that the water of the southern Al-Hawizeh Marsh has high average concentrations of salinity (9.2 ppt), electrical conductivity (14.8 mS/cm), and chloride (1749.4 mg/l), as its rise to record high values ​​by a large difference from the previous local studies, and thus it is more saline than the northern part of Al-Hawizeh Marsh due to the impact of the drought extending for nine consecutive years, which threatens to change a large area in the marsh environment may lead, in the event of the continuation of the current situation of lack of water revenues and the deterioration of environmental factors of the southern Al-Hawizeh marsh, to affect the important biodiversity of this vital area.

Semi-quantitative microfluidic paper-based analytical device for ionic silica detection.

Silicate ions (SiO32-), or ionic silica, are known to cause silica scaling in industrial water applications when excess amounts are present; hence, concentrations must be monitored and kept at a constant low level. Ionic silica is conventionally measured by spectrophotometry in the form of its silicomolybdic complex based on the molybdenum blue reaction, but the operation process is complicated and not suitable for on-site detection. To solve these issues, microfluidic paper-based analytical devices (µPADs) have been gaining attention as portable, low-cost analytical devices suitable for on-site detection. The foldable origami type device described in this work enabled silica detection based on the molybdenum blue reaction, in the range of 50-1000mg/L, with a practically detectable lowest concentration of 50mg/L. The device showed selectivity for silicate ions and stability over 21days when stored at 4°C. The semi-quantitative analytical performance makes the proposed paper-based device attractive for on-site industrial monitoring.

Multiple-Ion Releasing Bioactive Surface Pre-Reacted Glass-Ionomer (S-PRG) Filler: Innovative Technology for Dental Treatment and Care

Surface Pre-Reacted Glass-ionomer (S-PRG) filler, which releases strontium (Sr2+), borate (BO33-), fluoride (F-), sodium (Na+), silicate (SiO32-), and aluminum (Al3+) ions at high concentrations, is a unique glass filler that are utilized in dentistry. Because of its multiple-ion releasing characteristics, S-PRG filler exhibits several bioactivities such as tooth strengthening, acid neutralization, promotion of mineralization, inhibition of bacteria and fungi, inhibition of matrix metalloproteinases, and enhancement of cell activity. Therefore, S-PRG filler per se and S-PRG filler-containing materials have the potential to be beneficial for various dental treatments and care. Those include restorative treatment, caries prevention/management, vital pulp therapy, endodontic treatment, prevention/treatment of periodontal disease, prevention of denture stomatitis, and perforation repair/root end filling. This review summarizes bioactive functions exhibited by S-PRG filler and its possible contribution to oral health.

Novel agricultural waste based hardening accelerator for early strength development of fly ash-based concrete

Rapid urbanization is leading to a rise in demand for precast elements to reduce the time and cost of construction. However, precast elements consume the time to remove formwork during production depends on the early strength development of fresh concrete. On the other hand, thermal power plants produce a significant amount of fly ash, which also cause environmental issues. One solution to this problem is to use fly ash in cement and concrete to enhance their pozzolanic properties and address environmental concerns. However, using fly ash can delay the early strength development of concrete resulting deacceleration in the production cycle of precast elements. To speed up the process, some may opt for chemical-based hardening accelerator and high temperature curing. However, this may negatively impact the hydration kinetics of the concrete, pose environmental risks, and compromise the reinforced concrete’s durability.To overcome such limitations, impurity free C-S-H seed based hardening accelerator was synthesized from agricultural waste product namely, bagasse ash using novel chemical synthesis process which could effectively accelerates the early strength development of concrete without altering the conventional hydration process. The proposed synthesis process provides a platform for the reaction between the target calcium and silicate ions simultaneously eliminating the harmful elements (like chloride etc.) responsible for degradation of health of reinforced concrete structure.In order to study the effectiveness of a synthesized C-S-H seed, a blended ordinary Portland cement (OPC) was prepared by replacing 10%, 15%, and 20% of the cement weight with fly ash. Various amounts of the C-S-H seed were then added to the blend. Presence of developed C-S-H seed effectively reduced the setting time and eliminated the induction period during hydration of fly ash blended cement. Presence of additional seeds effectively reduces the critical free energy of nucleation which in turn accelerates the precipitation of hydration product responsible for the early strength development of fly ash-based concrete. Based on the setting time and heat of hydration analysis, it has been observed that the presence of C-S-H seed has the potential to accelerate the early strength gain process of fly ash-based concrete.

Extracellular vesicles engineering by silicates-activated endothelial progenitor cells for myocardial infarction treatment in male mice

Extracellular vesicles have shown good potential in disease treatments including ischemic injury such as myocardial infarction. However, the efficient production of highly active extracellular vesicles is one of the critical limitations for their clinical applications. Here, we demonstrate a biomaterial-based approach to prepare high amounts of extracellular vesicles with high bioactivity from endothelial progenitor cells (EPCs) by stimulation with silicate ions derived from bioactive silicate ceramics. We further show that hydrogel microspheres containing engineered extracellular vesicles are highly effective in the treatment of myocardial infarction in male mice by significantly enhancing angiogenesis. This therapeutic effect is attributed to significantly enhanced revascularization by the high content of miR-126a-3p and angiogenic factors such as VEGF and SDF-1, CXCR4 and eNOS in engineered extracellular vesicles, which not only activate endothelial cells but also recruit EPCs from the circulatory system.