Underwent Surface Modification Research Articles

Effect of ionic liquid on dispersion stability and antiwear behavior of CuO nanoparticles added to polyalphaolefin base oil

The experimental study assessed the impact of choline chloride cation-based ionic liquid (IL), on the dispersion stability and wear characteristics of copper (II) oxide (CuO) nanoparticles (NPs) in synthetic base oil (PAO 10). CuO NPs, averaging 50 nm in size, underwent surface modification using varying concentrations of the IL (0.25%, 0.5%, 0.75%, and 1% by weight). The formulations were subjected to sliding wear tests to evaluate their wear behavior. Analysis of the worn surfaces utilized scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy. The results indicated that the combination of 0.75% IL and 1% CuO NPs provided optimal dispersion and exhibited effective surface mending, enhancing wear protection by 21.1% than that of PAO 10. The formulation containing 1% IL and 1% CuO NPs demonstrated the highest load carrying capacity among all tested compositions. In terms of wear behavior, the nanolubricant formulations with 0.75% and 1% IL outperformed the lubricant formulation containing 1 wt% of the commercial antiwear additive Zinc dialkyldithiophosphates (ZDDP).

Cutting-edge applications of oleic acid-modified CdSiO3: Ce3+ phosphors: Artificial intelligence enhanced latent fingerprint detection, anti-counterfeiting and optical thermometry

A series of (1–11 mol%) Ce³⁺ doped CdSiO₃ phosphors are synthesized via a solution combustion method, and the sample with the optimal doping concentration underwent surface modification with oleic acid (OA). X-ray diffraction (XRD) analysis confirmed the formation of high-purity, well-crystallized CdSiO3:Ce3+ phosphors. Upon 347 nm UV excitation, the phosphor exhibited intense blue emission at 400 nm, with an optimized Ce³⁺ concentration of 5 mol%, attributed to dipole-dipole interactions. The OA-modified phosphor demonstrated significantly enhanced properties, achieving a color purity (CP) of 97.2% and Internal quantum efficiency (IQE) of 82.5%. The phosphor also exhibited excellent thermal stability, retaining 93.0% of its emission intensity at 423 K and a thermal quenching temperature exceeding 483 K, with a high activation energy (Eₐ) of 0.384 eV. In practical applications, the OA modified phosphor showed exceptional performance in latent fingerprints (LFPs) detection and anti-counterfeiting (AC) across different substrates, offering high resolution, contrast, and minimal background interference. MATLAB based analysis yielded a matching score of 94.52%, surpassing conventional benchmarks, underscoring the phosphor's potential for advanced fingerprint identification. These results demonstrate that the CdSiO₃:5Ce³⁺ phosphor is a promising candidate for applications in white light-emitting diodes (w-LEDs), optical thermometry, forensic analysis and AC technologies.

Nascently generated microplastics in freshwater stream are colonized by bacterial communities from stream and riparian sources.

The purpose of this study was to examine bacterial colonization of different types of microplastics through time in a freshwater ecosystem. Microplastics are persistent pollutants in aquatic ecosystems. Bacteria readily colonize microplastic surfaces and may contribute to their degradation, but the taxa involved, and their degradative abilities, differ based on factors such as microplastic chemistry, plastic age, and specific ecosystem types. Four different common types of newly manufactured microplastics, high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene, were incubated for 7 weeks in a freshwater stream and sampled. Sample collection was timed to examine the development of early and late bacterial biofilm communities. Microplastics were analyzed for changes to buoyancy, weight, contact angles (an indicator of surface roughness), bacterial community composition, and the number of bacterial cells. Time was the only significant contributing factor in the development of bacterial biofilm communities on microplastic disks over the 7-week study. Notably, the Comamonadaceae were abundant early in the study and decreased in abundance with time, while the Methylococcaceae demonstrated the opposite trend. Different physicochemical properties among the various types of microplastics had only a minor effect on bacterial community compositions of biofilms growing on the microplastics. Additionally, the surfaces of all microplastic disks became rougher over time in the stream. Collectively, our results show that microplastic surfaces undergo surface modification and community succession as time progresses, regardless of microplastic type, in a freshwater stream ecosystem.

Formation of ceramic coatings on non-valve metal low carbon steel using micro-arc oxidation technology

Valve metals are metals that can undergo surface modification through micro-arc oxidation (MAO). Iron is not considered a valve metal and cannot undergo MAO. Steel is a widely used alloy due to its excellent properties, including high toughness, good workability, and low cost. However, its weak corrosion and abrasion resistance limit its range of application and service life. Al2O3 ceramic coating is formed on the surface of non-valve metal low carbon steel using MAO technology. The surface morphology and composition of the MAO coatings on non-valve metals are investigated through characterization. Tribological experiments show that the coefficient of friction of the samples obtained from the MAO power supply frequency of 1400 Hz is the smallest. After conducting a corrosion resistance test following MAO treatment, the impedance increased by three orders of magnitude and the corrosion rate decreased by one order of magnitude. The use of MAO treatment can expand the use of steel and shows promise for application to other non-valve metals.

Electrochemical Properties of Li4Ti5O12 Coated LiMn0.6Fe0.4PO4 Prepared by Rheological Phase Reaction Method

Abstract In this study, we fabricated LiMn0.6Fe0.4PO4/C (LMFP/C) materials employing the spray drying method. Subsequently, the LMFP/C composites underwent surface modification with Li4Ti5O12 (LTO) using the rheological phase reaction method. LTO demonstrates high electrochemical activity and possesses significantly greater lithium-ion conductivity compared to LMFP. The developed composite coating serves a dual purpose by safeguarding the LMFP material against electrolyte erosion and facilitating the swift transfer of lithium ions and electrons. The results from transmission electron microscopy and energy-dispersive X-ray spectroscopy validated the successful coating of LTO onto the LMFP/C surface after the surface modification treatment. A comparative analysis was conducted between the pristine LMFP/C powder and the LMFP-LTO composite that underwent surface modification. The results reveal that the 2 wt. % LTO-coated LMFP/C composite has the best electrochemical performance, manifesting specific capacities of 156 and 132.6 mAh·g-1 at 0.2 and 5 C rate, respectively. Furthermore, the material demonstrated excellent cycle retention, with 95.4% capacity retention after 100 cycles at 1 C. Hence, LTO coating can be considered an efficacious strategy for enhancing the electrochemical performance of LMFP.

Biocatalytic Performance of β-Glucosidase Immobilized on 3D-Printed Single- and Multi-Channel Polylactic Acid Microreactors.

Microfluidic devices have attracted much attention in the current day owing to the unique advantages they provide. However, their application for industrial use is limited due to manufacturing limitations and high cost. Moreover, the scaling-up process of the microreactor has proven to be difficult. Three-dimensional (3D) printing technology is a promising solution for the above obstacles due to its ability to fabricate complex structures quickly and at a relatively low cost. Hence, combining the advantages of the microscale with 3D printing technology could enhance the applicability of microfluidic devices in the industrial sector. In the present work, a 3D-printed single-channel immobilized enzyme microreactor with a volume capacity of 30 μL was designed and created in one step via the fused deposition modeling (FDM) printing technique, using polylactic acid (PLA) as the printing material. The microreactor underwent surface modification with chitosan, and β-glucosidase from Thermotoga maritima was covalently immobilized. The immobilized biocatalyst retained almost 100% of its initial activity after incubation at different temperatures, while it could be effectively reused for up to 10 successful reaction cycles. Moreover, a multi-channel parallel microreactor incorporating 36 channels was developed, resulting in a significant increase in enzymatic productivity.

Predictable and adjustable broadband gold nanorods for photothermal effects and foldable performances

Colloidal gold nanorods (GNRs) have demonstrated their potential to absorb light within specific wavelength bands and induce photothermal effects. However, the unpredictability and lack of adjustability in the broadband spectrum formed by the self-assembly of gold nanospheres or the coupling of various sizes of GNRs have posed significant challenges. To address this, we have developed broadband GNRs (BGNRs) with a predictable and adjustable extinction band in the visible and near-infrared regions. The BGNRs were synthesized by simply mixing GNRs with different aspect ratios, allowing for control over the bandwidths and positions of the extinction bands. Subsequently, the BGNRs were coated with silica and underwent surface modification. The resulting BGNRs@SiO2 were then mixed with either polydimethylsiloxane (PDMS) or polyvinylidene fluoride (PVDF) to create BGNRs@SiO2/PDMS (or PVDF) films. The BGNRs@SiO2/PDMS and BGNRs@SiO2/PVDF films both exhibit excellent photothermal performance properties. Additionally, the light absorption intensity of the BGNRs@SiO2/PVDF film linearly increases upon folding, leading to significantly enhanced photothermal performance after folding. This work demonstrates that plasmonic colloidal GNRs, without the need for coupling, can yield predictable and adjustable extinction bands. This finding holds great promise for future development and practical applications, particularly in the transfer of these properties to films.

Janus particles: features, synthesis and potential uses, including surface functionalisation

ABSTRACTAs the development of nanostructured materials continues to blossom, there is increasing attention to functionalised particles. The so-called Janus particles are anisotropic regions having different physicochemical properties. The recent development of their synthesis in a pH field during suspension as bipolar particles between electrodes has opened the door to improved scalability due to the ease of entraining particles as a slurry in a flowing electrolyte stream. Potential application areas span catalysis of chemical synthesis, sustainable energy conversion and pharmaceutical and biomedical sectors of industry. In view of their versatility, the ability to undergo surface modification and opportunities for facile scale-up, Janus particles might be deployed as building blocks to fabricate functional surfaces having tailored chemical, structural and surface anisotropy. They could prove to be valuable feedstock in 3-D printing and surface finishing of fast prototype components and devices.

Flow diverter surface modifications for aneurysm treatment: A review of the mechanisms and data behind existing technologies.

Flow diversion (FD) has become a mainstay treatment for large wide-necked aneurysms. Despite excellent safety and efficacy, the risk of thromboembolic complications necessitates the use of dual antiplatelet therapy (DAPT). The use of DAPT makes hemorrhagic complications of stenting carry high morbidity and mortality. Additionally, DAPT usage carries a risk of "nuisance" complications that do not directly impact intracranial circulation but need to be managed nonetheless. To circumvent this issue, the most recent generation of flow diverters have undergone surface modification with various compounds to confer blood compatibility to limit clotting and thrombosis. While these newer generation flow diverters are marketed to enhance ease of deployment, the goal is to eventually facilitate single antiplatelet use with flow diverter treatment. This generation of FDs have potential to expand indications beyond unruptured wide-necked aneurysms to include ruptured intracranial aneurysms without the necessity of DAPT. Currently, no comprehensive review details the molecular mechanisms and pre-clinical and clinical data on these modifications. We seek to fill this gap in the literature by consolidating information on the coating technology for four major FDs currently in clinical use-PipelineTM Flex and Vantage Shield TechnologyTM, FREDTMX, p48/64 hydrophilic coating, and Acandis Dervio® 2heal-to serve as a reference guide in neurointerventional aneurysm treatment. Although the Balt silkTM was one of the first FDs, it is uncoated, thus we will not cover this device in our review. A literature review was performed to obtain information on each coating technology for the major flow diverters currently on the market using international databases (PUBMED, Embase, Medline, Google Scholar). The search criteria used the keywords for each coating technology of interest "phosphorylcholine," "poly 2-methoxyethyl acrylate," "hydrophilic polymer coating," and "fibrin-heparin" Keywords related to the device names "Pipeline Shield," "Pipeline Shield with Flex Technology," "FRED," "FREDX," "p64," "p64-HPC," "Derivo 2heal" were also used. Studies that detailed the mechanism of action of the coating, any pre-clinical studies with surface-modified intravascular devices, and any clinical retrospective series, prospective series, or randomized clinical trials with surface-modified devices for aneurysm treatment were included.

Effect of Highly Hydrophilic Superparamagnetic Iron Oxide Nanoparticles on Macrophage Function and Survival.

Superparamagnetic iron oxide nanoparticles (SPIONs) have garnered significant attention in the medical sector due to their exceptional superparamagnetic properties and reliable tracking capabilities. In this study, we investigated the immunotoxicity of SPIONs with a modified surface to enhance hydrophilicity and prevent aggregate formation. The synthesized SPIONs exhibited a remarkably small size (~4 nm) and underwent surface modification using a novel "haircut" reaction strategy. Experiments were conducted in vitro using a human monocytic cell line (THP-1). SPIONs induced dose-dependent toxicity to THP-1 cells, potentially by generating ROS and initiating the apoptotic pathway in the cells. Concentrations up to 10 μg/mL did not affect the expression of Nrf2, HO-1, NF-κB, or TLR-4 proteins. The results of the present study demonstrated that highly hydrophilic SPIONs were highly toxic to immune cells; however, they did not activate pathways of inflammation and immune response. Further investigation into the mechanisms of cytotoxicity is warranted to develop a synthetic approach for producing effective, highly hydrophilic SPIONs with little to no side effects.

Biopharmaceutical and nanotoxicological aspects of cyclodextrins for non-invasive topical treatments: A critical review.

Cyclodextrins are nanometric cyclic oligosaccharides with amphiphilic characteristics that increase the stability of drugs in pharmaceutical forms and bioavailability, in addition to protecting them against oxidation and UV radiation. Some of their characteristics are low toxicity, biodegradability, and biocompatibility. They are divided into α-, β-, and γ-cyclodextrins, each with its own particularities. They can undergo surface modifications to improve their performances. Furthermore, their drug inclusion complexes can be made by various methods, including lyophilization, spray drying, magnetic stirring, kneading, and others. Cyclodextrins can solve several problems in drug stability when incorporated into dosage forms (including tablets, gels, films, nanoparticles, and suppositories) and allow better topical biological effects of drugs at administration sites such as skin, eyeballs, and oral, nasal, vaginal, and rectal cavities. However, as they are nanostructured systems and some of them can cause mild toxicity depending on the application site, they must be evaluated for their nanotoxicology and nanosafety aspects. Moreover, there is evidence that they can cause severe ototoxicity, killing cells from the ear canal even when applied by other administration routes. Therefore, they should be avoided in otologic administration and should have their permeation/penetration profiles and the in vivo hearing system integrity evaluated to certify that they will be safe and will not cause hearing loss.

Characteristics of alginate and soy protein isolates composite aerogels as oil absorbent

Treating oil spill occurrence is crucial because of the toxic effects on marine life and the environment. Hence, absorption is used for a low-cost oil recovery process, simple mechanism, and sustainability to mitigate such occurrence. Synthetic absorbent is always associated with its poor degradability, which may cause water to turn toxic. Natural materials have been foreseen as excellent absorbent due to their cost-effectiveness, sustainability, and less environmental harm. In this work, alginate/soy protein isolates (SPI) aerogels are synthesized, undergo surface modification with methyltrimethoxysilane (MTMS) and tetraethyl orthosilane (TEOS) solution, and then dried by supercritical CO2 at 110 ± 5 bar and 40 °C in 4h to produce aerogels absorbent. The synthesized absorbents were analyzed via FTIR, TGA, DSC, FESEM, contact angle and oil absorption analysis to determine their physical and chemical properties. Results demonstrated that the hydrophilic surface of the alginate/soy protein isolate could be tailored in a simple surface modification process. Its oil absorption capacity towards the engine oil can reach a range of 9.1-12.1 g/g, comparable to most reported natural absorbents. Thus, the findings in this study show that alginate/ SPI aerogels may have potential as an industry oil absorbent.

Investigation of the "Nose-to-Brain" Pathways in Intranasal HupA Nanoemulsions and Evaluation of Their in vivo Pharmacokinetics and Brain-Targeting Ability.

PurposeWhile developing huperzine A (HupA) to explore new approaches to treating Alzheimer’s disease (AD), intranasal administration was proposed as an alternative route to deliver drugs into the brain. This study aimed to prepare nanoemulsions (NEs) of HupA to investigate their potential “nose-to-brain” pathways and to evaluate their pharmacokinetic and brain-targeting parameters.MethodsHupA-NE and Lf-HupA-NE that underwent surface modification with lactoferrin (Lf) were characterized to determine various physicochemical properties, such as their size, PDI, zeta potential, pH, and loading efficiency; in addition, transmission electron microscopy and stability assessments were performed. We utilized an aggregation-caused quenching (ACQ) probe to monitor intact NEs in the brains of olfactory nerve transection model and normal rats. Immunohistochemistry, pharmacokinetic and targeting index analyses were performed to investigate the in vivo effects of HupA-NE and Lf-HupA-NE.ResultsBased on the live imaging results, HupA-NE and Lf-HupA-NE could be transported into the brain via nerve and blood circulation pathways. Immunohistochemical staining tests demonstrated that the efflux proteins P-gp, MRP1, and BCRP were expressed in brain tissue. NEs can inhibit efflux pumps to improve drug concentrations in the brain. The findings of this study showed that NEs (especially Lf-HupA-NE) had better pharmacokinetic profiles and a better nose-to-brain drug transport efficiency than free HupA.ConclusionThe newly designed formulations might contribute to the transport and accumulation of HupA to achieve therapeutic results. The delivery system may be a promising strategy for the brain-targeted delivery of HupA.

(Digital Presentation) Design and Development of Electrochemical Immunosensor for Brain-Related Protein

The process of diagnosis for neurodegenerative diseases relies on the onset of symptoms. However, there is the possibility of detecting these diseases, such as amyotrophic lateral sclerosis (ALS), before progression, which would allow for more treatment. ALS is a neurodegenerative disease that targets the motor system. As the disease progresses, individuals experience a loss in mobility in their appendages and limbs and eventually total muscle paralysis. The development of new diagnostic tools will allow for earlier treatment and provide a greater time frame between diagnosis and disease onset. Early detection of ALS can be achieved by detecting biomarkers associated with the disease, one of which is the TDP-43 protein. Using electrochemistry, miniaturized and portable biosensors which provide rapid response are ideally suited for the point of care applications. Towards this goal, we developed a label-free biosensor based on the electrochemical impedance spectroscopy (EIS). The signal output was the charge transfer resistance (Rct) of the antibody-surface before and after protein exposure. The changes in the Rct values were directly related to the amount of analyte. The sensor used in these experiments was synthesized using a gold disk working electrode, which underwent surface modification, to add TDP-43 antibodies to the surface. After surface modification, the immunosensor optimization was carried out by using several commercial TDP-43 antibodies at various concentrations. The significant changes in Rct values were observed above 100 nM concentration of the protein. This study provides the methodology for fabricating a sensor recognition layer for TDP-43 specifically, but can be easily extended for detection of other disease-related biomarkers.

(Digital Presentation) Surface Modifications of Cathodes By Coating: A Step Towards Improving the Electrochemical Performance of Lithium Ion Batteries (LIBs)

Lithium-ion batteries (LIBs) have been widely utilized as power sources for mobile devices. Recently, their use has been expanded to large-scale applications such as electric vehicles (EVs) and energy storage systems (ESSs). These batteries have dominated the energy industry due to their unmatchable properties that include a high energy density, a compact design, and an ability to meet a number of required performance characteristics in comparison to other rechargeable systems. Two vital parameters for LIBs are their stable and safe operation. Since, the cathode serves as a central component of LIBs, the overall cell performance is significantly affected by the chemical and physical properties of the cathode. Cathodes tend to react with the electrolytes and, hence, undergo surface modifications accompanied by degradation. These side-reactions result in an erosion of battery performance and rate capability, thereby causing a reduced battery life and power capacity. Surface coating is the most simple, economical and effective method to protect the cathode surface from degradation and detrimental interfacial reactions with the electrolyte. For the present investigation, a variety of coatings have been used to coat cathode surface. The aim is to explore the effect of these coatings on the physicochemical characteristics as well as electrochemical and thermal properties of spinel cathode using characterization techniques like scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) and differential thermal analysis (DTA)/ thermogravimetric analysis (TGA).

Recent advances of boron-doped diamond electrochemical sensors toward environmental applications

The electrocatalytic properties of boron-doped diamond (BDD) electrodes have been considered for a variety of sensing applications. The unusual electrochemical properties of BDD include a large potential window, a small background current, and better resistance to fouling than other carbon-based electrodes. The use of BDD for remediation and environmental sensing applications has recently attracted the interest of the sensor research community. This review focuses on recent developments that involve the use of BDD as an environmentally friendly sensing material for environmental analysis. The electrochemical properties of boron-doped diamond that has undergone surface modification (e.g., with metals or enzymes) will be considered. Recent achievements involving the use of BDD electrodes for detecting pesticides, mycotoxins, peroxides, and phenolic compounds are considered.

Inter-diffusion and stability studies in W/Cr and W/Fe films using ion beam analysis

Plasma facing components in fusion reactors are exposed to intense plasma and the accompanying thermal loads and undergo surface modification due to sputtering and thermal diffusion. In order to get insight into the thermal diffusion in reduced-activation ferritic/martensitic (RAFM) steel, a prominent W containing plasma facing material, the compositional, structural and morphological changes occurring in W/Cr and W/Fe bi-layered films on vacuum annealing in 373–873 K temperature range were investigated. Compositional analysis by ion beam techniques established the out-diffusion of Cr and Fe through the W layer to the top surface. The diffusion coefficients of Cr and Fe in W were determined to be 8.0 × 10-19 (at 873 K) and 9.75 × 10-18 m2/s (at 773 K) respectively. The out-diffusion of Cr and Fe was substantiated by diffraction studies; however, no inter-metallic phases were formed. Annealing, besides promoting grain growth also introduced roughness in films.

The Surface Characterisation of Fused Filament Fabricated (FFF) 3D Printed PEEK/Hydroxyapatite Composites.

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer which has found increasing application in orthopaedics and has shown a lot of promise for ‘made-to-measure’ implants via additive manufacturing approaches. However, PEEK is bioinert and needs to undergo surface modification to make it at least osteoconductive to ensure a more rapid, improved, and stable fixation that will last longer in vivo. One approach to solving this issue is to modify PEEK with bioactive agents such as hydroxyapatite (HA). The work reported in this study demonstrates the direct 3D printing of PEEK/HA composites of up to 30 weight percent (wt%) HA using a Fused Filament Fabrication (FFF) approach. The surface characteristics and in vitro properties of the composite materials were investigated. X-ray diffraction revealed the samples to be semi-crystalline in nature, with X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry revealing HA materials were available in the uppermost surface of all the 3D printed samples. In vitro testing of the samples at 7 days demonstrated that the PEEK/HA composite surfaces supported the adherence and growth of viable U-2 OS osteoblast like cells. These results demonstrate that FFF can deliver bioactive HA on the surface of PEEK bio-composites in a one-step 3D printing process.

Engineering alginate microparticles for optimized accumulation in fetal rat myelomeningocele

IntroductionIntraamniotic microparticle injection is a novel technique for the treatment of myelomeningocele (MMC) in which microparticles are delivered in-utero in a minimally invasive fashion to bind to and protect the exposed spinal cord. This technique could offer earlier intervention and greater access to prenatal treatment of MMC. Here we demonstrate progress on the engineering of the microparticles to promote binding to the MMC defect. We hypothesized that when the particle's surface charge was decreased and delivery concentration increased, particles would bind to the MMC defect more frequently and more specifically. MethodsAlginate microparticles underwent surface modification to alter the particle charge. Dye-loaded alginate, alginate- dextran sulfate, and alginate- chitosan were injected on e17 into the amnion of a rat model of MMC and the incidence of successful binding and specificity of particle binding to the MMC defect were calculated. Specificity of binding was described using a defect-to-skin brightness ratio based on specimen imaging. Comparisons were made with chi-square, p< 0.05 marked significance. ResultsThere was no difference in the incidence of successful binding at e17 with 0.6 mg/fetal kg between the three tested alginate particles. However, alginate- dextran sulfate bound most specifically to the defect (p< 0.05). Alginate-dextran sulfate also demonstrated more frequent binding at higher doses than lower doses (79% at 1.2 mg/kg vs 38% at 0.6 mg/kg and 24% at 0.8 mg/kg, p< 0.01 for both). Specificity was not sacrificed at higher dose injections: defect-to-skin brightness ratio of 5.4 at 1.2 mg/kg vs 1.8 at 0.6 mg/kg (p< 0.05) ConclusionWe demonstrate that the intraamniotic injection of alginate-dextran sulfate microparticles at high concentration bind more frequently and more specifically to MMC defects than the previously tested unmodified alginate microparticles.

Increase in gold dissolution in copper ammonia thiosulfate solution via cobalt surface modification

When gold was leached using copper ammonia thiosulfate solution, the dissolution rate of gold decreased as the leaching time increased. The dissolution of gold powder with 44 and 77 μm particles was studied，and the results indicated that the dissolution rate was not decreased by surface passivation or the decrease in copper concentration but by the changes of the electronic structure of the gold surface caused by the change in the exposed crystal surface. The transmission electron microscopy images of the gold powder revealed that the high-index (220) and (311) crystal surfaces almost disappeared during leaching. Furthermore, the surface of gold consisted mainly of the low-index (111) crystal surface during the later stages of leaching. Owing to the changes in crystal surface, the work function of the gold surface increased from 6.56 to 6.95 eV, and the increase in work function hindered the loss of electrons from the gold surface. When cobalt was used to modify the gold surface, the work function decreased from 6.56 to 5.99 eV. The leaching results indicated that the cobalt modification increased gold dissolution, and the gold leaching percentage was increased by 40% within 8 h. the tendency of gold to dissolve more easily after it underwent surface modification was confirmed by the apparent activation energy of the surface-modified being lower than that of the fresh gold powder, the formation of intermediate products of Co3O4 with high oxidation ability and the galvanic interaction between cobalt and gold electrodes. Dry-grind was applied for gold concentrate calcine and different contents of cobalt powder to study the possibility of industrial application of this effect. The results showed that only adding 50 mg cobalt to 100 g gold ores was beneficial to gold leaching