Silver Ions Research Articles

One-step construction of silver nanoparticles immersed hydrogels by triple-helix β-glucans and the application in infectious wound healing

Hydrogels composed of polysaccharides and silver nanoparticles (AgNPs) are widely recognized for their applications in wound dressings, particularly for healing wounds prone to infection. Traditional methods for preparing AgNPs immersed hydrogels are often complex, costly, and may lead to sustained cytotoxicity. To address these challenges, we developed a biocompatible, one-step green reduction strategy to generate AgNPs within hydrogels using a triple-helix β-glucan (PCPA) derived from Poria cocos, a renowned Chinese traditional herb. PCPA serves as a reducing agent, converting silver ions into AgNPs while its triple-helix conformation prevents AgNPs aggregation. The resulting hydrogel (PAg-G) is injectable and contains uniformly distributed AgNPs. PAg-G exhibits broad-spectrum antimicrobial activity and enhanced bioactivity. The in vivo study on S.aureus-infected SD rats demonstrated that PAg-G can accelerate wound healing within 12 days by down-regulating inflammatory factors such as IL-6 and TNF-α, and up-regulating VEGF and CD31 expression, promoting neovascularization in wound tissues. This innovative one-step construction of AgNPs immersed hydrogels offers a promising approach for the development of antimicrobial hydrogels, especially for treating bacterial-infected wounds.

A Novel Approach to Produce Metal–Metal Composites by Leveraging Immiscibility: Laser Powder Bed Fusion of Nanosilver‐Dispersed Titanium

The antimicrobial properties of silver ions are well known and effectively utilized in various biomedical applications. The efficacy of silver‐containing materials, particularly in terms of antimicrobial activity, heavily relies on the oxidizing surface, favoring nanosized silver features. However, producing such structures is challenging due to the high probability of miscibility in the liquid phase. Developing Ti–Ag composite alloys using the laser powder bed fusion technique with supported titanium powders and silver nanoparticles (AgNPs) represents a novel research pursuit, with no prior investigations reported. Incorporating AgNPs into titanium forms nanoislands, directly enhancing the antimicrobial efficacy of biomedical components. In this study, it is aimed to explore the solubility limit of silver in titanium and the feasibility of achieving finely dispersed silver islands. Experimental findings reveal that incorporating AgNPs into Ti‐based alloys results in discrete silver islands (0.01–0.02 μm2) within the microstructure, governed by the solubility limit of silver in titanium. In this study, valuable insights into producing components with augmented biocompatibility and proven antibacterial properties against Staphylococci infections are offered. The successful development of Ti–Ag composite alloys, featuring finely dispersed silver islands, opens promising avenues for biomedical applications, enhancing their antibacterial characteristics and improving patient outcomes.

Incorporation of Silver into Sulfate Groups Enhances Antimicrobial and Antiviral Effects of Fucoidan.

The COVID-19 pandemic has significantly impacted our daily lives. Routine infection-control measures present an effective preventive strategy for a new infectious disease outbreak. Fucoidan, a fucose-rich sulfated polysaccharide found in brown algae, exhibits antiviral activity. Moreover, fucoidan exerts an antimicrobial effect; however, it requires considerably higher concentrations than those needed for its antiviral effect. In this study, we aimed to enhance the antimicrobial activity of fucoidan and prepared a fucoidan silver salt (Ag-Fuc) by incorporating silver ions into the sulfate groups of Yakult Fucoidan derived from Cladosiphon okamuranus Tokida. The fucoidan exhibited a weak inhibitory effect on Escherichia coli growth at significantly higher concentrations, whereas Ag-Fuc inhibited the growth of E. coli and Staphylococcus epidermidis at concentrations comparable to those required for its antiviral effects. Moreover, Ag-Fuc inhibited the growth of Cladosporium cladosporioides. Infections of human cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus were more effectively inhibited by lower concentrations of Ag-Fuc compared with fucoidan. Overall, silver ions added to the sulfate groups induced strong antimicrobial activity and enhanced the antiviral effect of fucoidan. We suggest a wide application of Ag-Fuc as a routine preventive material to avoid new infectious disease pandemics.

Record high photocurrent density of In:Ag2S/ZnO heterojunction enabled by controllable doping for efficient solar hydrogen production

The high mobility of silver ions (Ag+) in silver sulfide (Ag2S) promotes vacancy formation, which serves as the recombination center of the photoexcited charge carriers to severely limit the photoelectrochemical activity of Ag2S. To address this issue, trivalent indium (In3+) is particularly introduced into Ag2S via low–temperature successive ionic layer adsorption and reaction (SILAR) technique, by which are the migration and the side reactions of Ag+ to form the phase impurities largely suppressed. Herein, In3+ is preferentially chosen due to its two more valence electrons with respect to that of Ag+, effectively increasing the carrier concentration of In:Ag2S to not only improve its electrical conductivity but also uplift its Fermi level. The photoexcited electron transport is thereby accelerated to more efficiently separate from the geminate holes, which is further reinforced by depositing In:Ag2S on the zinc oxide nanorods (ZnO NRs) with a relatively low–lying Fermi level. The photogenerated holes are rectified by the built–in electric field at the In:Ag2S/ZnO heterojunction to flow in an opposite direction to that of the electrons, between which the recombination is thereby suppressed. Meanwhile, the light harvesting ability of In:Ag2S/ZnO NRs is also enhanced due to its reduced band gap by In3+. Their synergistic effect renders In:Ag2S/ZnO NRs developed in the present contribution to deliver a record–high photocurrent density of 7.7 mA cm−2 under one–sun illumination, which far exceeds those of not only the undoped counterpart but also additional Ag2S–based photoelectrodes reported in the literature.

LIFs-Based Fluorescent Analysis of Silver Ions in Water Using AIEgen-Embedded PVA Hydrogel.

The detection and quantification analysis of silver ions is important to protect human health and improve the level of wastewater treatment. In this work, a polyvinyl alcohol (PVA) hydrogel-based sensing material based on an aggregation-induced emission strategy was developed and combined with a portable laser-induced fluorescence spectroscopy (LIFs) device for the direct detection and quantification of silver ions in water. Considering the requirements of environmental water analysis regarding portability, reliability, and convenience, this fluorescence turn-on strategy was optimized accordingly to ensure the accuracy and stability of the analysis in complex natural water environmental. This sensing method showed operational excellence and good sensitivity (down to 1 ppb) and may provide a stable and convenient strategy for the on-site, real-time analysis of environmental water samples.

Comparison of silver nanoparticles and AgNO<sub>3</sub> toxic effects on <i>Caenorhabditis elegans</i> with a genetic disorder of copper metabolism

BACKGROUND: Silver nanoparticles are widely used in various types of industry, but their safety for humans has not been strictly proven. The experimental data currently available on the comparison of the toxic effect of silver nanoparticles and AgNO3 are contradictory and the question of the priority use of silver nanoparticles remains open, especially for organisms with impaired copper metabolism. AIM: The main aim of this study is to compare the effects of silver nanoparticles and AgNO3 on the nematode with normal and impaired copper metabolism and draw conclusions about their toxicity. MATERIALS AND METHODS: In this work, we determined the sublethal concentration (LC50) of AgNPs and AgNO3 for H828Q nematode strain. Using the results obtained, we performed the development assay, thrashing assay and lifespan analysis of the animals. RESULTS: It has been shown that LC50 of silver nanoparticles is lower than the one for AgNO3. Caenorhabditis elegans with impaired copper metabolism treated with silver nanoparticles have a statistically significant reduction in development, level of mobility and lifespan, comparing to animals treated with AgNO3. CONCLUSIONS: The results obtained allow us to conclude that the toxic effect of silver nanoparticles on C. elegans with a genetic defect in copper metabolism is higher comparing to ionic silver.

Thermodynamics of Solvation of Silver(I) Ion in Nonaqueous Solvents

Thermodynamics of Solvation of Silver(I) Ion in Nonaqueous Solvents

Examining the Influence of Silver(I) Ion Coordination Environment in Ionic Liquids on Olefin-Paraffin Separations using Inverse Gas Chromatography.

Silver(I) ions (Ag+) undergo selective π-complexation with olefins and have been employed as separation media for the isolation of olefins from structurally similar paraffins. Ionic liquids (ILs) possess minimal vapor pressures, exceptional thermal stabilities, low melting points, as well as provide a favorable environment for π-complexation between Ag+ ions and olefins. The development of molecular drivers capable of highly selective olefin/paraffin separation systems with Ag+-containing ILs necessitates a comprehensive understanding of all factors that affect olefin solubility and selectivity. This study examines how coordinating different ligand species to Ag+ ions produces separation media with varying interaction strengths to olefins. Four coordination compounds, (4,4'-dimethyl-2,2'-bipyridine)silver(I) bis[(trifluoromethyl)sulfonyl]imide ([Ag+(DMBP)][NTf2-]), bis(pyridine)silver(I) [NTf2-] ([Ag+(Py)2][NTf2-]), bis(2,6-lutidine)silver(I) [NTf2-] ([Ag+(Lut)2][NTf2-]), and (triphenylphosphine)silver(I) [NTf2-] ([Ag+(PPh3)][NTf2-]) were dissolved in the 1-decyl-3-methylimidazolium [NTf2-] ([DMIM+][NTf2-]) IL and employed as stationary phases for inverse gas chromatography. Ligand coordination to the Ag+ ion was observed to modulate interactions of unsaturated hydrocarbons. The [Ag+(Py)2][NTf2-] complex offered the greatest olefin retention among the coordination complexes reaching 54% of the 1-octene retention factor of the uncoordinated [Ag+][NTf2-]. Hydrogen (H2) exposure studies showed ligand-dependent rates of reduction from Ag+ ion to elemental silver (Ag0). The [Ag+(PPh3)][NTf2-] complex exhibited superior stability, compared to the neat [Ag+][NTf2-] salt, reducing the retention factor of 1-octene by 15.3% and 19.4%, respectively, after 200 h of H2 exposure at 70 °C. The results from this study show that coordination complexes with Ag+ ions are useful in highly selective and efficient petroleum processing systems.

Selective Electrochemical Conversion of CO2 into Methane on Ag-Decorated Copper Microsphere.

We synthesized the silver-decorated copper microsphere via the hydrothermal method followed by photoreduction of silver ions. Sub 100 nm Ag nanoparticles anchored on the surface of Cu microspheres enhance the electrochemical performance and the selectivity of the CO2 reduction into CH4. Incorporating Ag nanoparticles onto Cu lowers the charge transfer resistance, enhancing the catalyst's conductivity and active site and increasing the rate of CO2 reduction. The faradaic efficiency of silver nanoparticles decorated copper microsphere for methane was 70.94 %, almost twice that of a copper microsphere (44 %). The electrochemical performance showed higher catalytic properties, stability, and faradaic efficiency of silver-decorated copper microspheres.

Aqueous dispersions of ‘green’ silver nanoparticles for eco-applications: Synthesis, structure and biosafety

Sustainable agriculture requires the use of intelligent compounds with multifaceted effect on soil and plants. Such conditioners can be hydrogels enriched with nanoparticles, but only those synthesized using ‘green chemistry’ methods. Therefore, the main aim of the study was to synthesize and characterize innovative ‘green’ silver nanoparticles (AgNPs) for agricultural applications. AgNPs were created using water or alcohol extracts of eucalyptus (Eucalyptus viminalisLabill) and aloe (Aloë arborescens Mill) as well as tannin to reduce silver ions (Ag+) to zero valent form (Ag0). The synthesis was conducted under autoclave conditions or at room temperature, in the presence of potassium carbonate. The AgNPs characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) method, whereas stability of the AgNPs suspensions under various conditions was estimated using turbidimetry. Biosafety of the formed species was determined based on genotoxicity (comet test) and cytotoxicity (study with crystal violet and MTT) assays. The obtained results confirmed the presence of zero valent silver phase in the nanoparticles and showed that their crystallite size was 14–24 nm, with different degrees of polydispersity depending on the synthesis conditions. Hydrodynamic diameter of AgNPs and their aggregates in the aqueous dispersions varied from 6 nm to 103 nm, and the smallest aggregation degree was noted for the nanoparticles synthesized using tannin. All synthesized nanoparticles were biosafe. Thus, they can be applied in agro-industrial processes without damaging the environment.

Highly-efficient recovery of silver from industrial cyanide-based plating effluent on TiO2/activated carbon composites

The release of silver-containing wastewater is an economic loss. In this works, the silver ions in the cyanide-based plating effluent of jewelry effluent was systematic recovered by the photocatalytic process using commercial semiconductors (TiO2, ZnO, Bi2O3 and WO3) and activated carbon (AC) enhanced semiconductors as the photocatalysts. The preliminary results demonstrated that the highest photocatalytic silver recovery was achieved via the use of TiO2 nanoparticles (NPs), ascribing to its better textural property that provided abundant active sites to undergo the reaction. The intrinsic property and activity of TiO2 were significantly improved in the presence of proper content of AC. Approximately 94% of silver was recovered within 45 min through the TiO2/AC with 14.9 wt% AC (TiO2/AC1) under the UV–vis irradiation due to the act of AC as the conductive pathway for electron migration from CB of TiO2 along its surface, thus prolonging the lifetime of electron-hole pairs. Although a marked decrease in photocatalytic activity of the best composite was detected after the 4th use (∼50%), it exhibited an outstanding antibacterial ability compared with TiO2 and fresh one in dark environment. The work offers the avenue to design the photocatalyst for recovering the precious metals from industrial effluent and broaden the application of such recovered metal decorated photocatalyst for practical use.

Enhanced NO2 Gas Sensing in Nanocrystalline MoS2 via Swift Heavy Ion Irradiation: An Experimental and DFT Study.

Nanostructured transition metal dichalcogenides (TMDs) like MoS2 hold promise for gas sensing applications due to their exceptional properties. However, limitations exist in maximizing sensor performance, such as limited active sites for gas interaction and sluggish response/recovery times. This study explores swift heavy ion (SHI) irradiation as a strategy to address these challenges in MoS2-based NO2 gas sensors. MoS2 nanoflakes were fabricated and subsequently irradiated with 120 MeV silver (Ag) ions to induce structural and morphological modifications. Characterization techniques confirmed the formation of Mo and S vacancies within the MoS2 lattice due to irradiation. Significantly, SHI irradiation resulted in a remarkable enhancement of approximately 3 times improvement in sensing response compared to pristine MoS2 sensors. Additionally, the irradiated sensors exhibit substantial improvements in both response and recovery times for NO2 detection. SHI irradiation resulted in the formation of self-affine nanostructures and increased grain fragmentation as fluence rises. This enhanced surface area is hypothesized to promote gas-sensor response. To gain deeper insights into the underlying mechanism, first-principles calculations were employed. These calculations suggest that electron transfer occurs from the MoS2 surface to the NO2 molecule during interaction. Furthermore, the irradiation-induced vacancies facilitate stronger NO2 adsorption on the MoS2 surface compared to the pristine sample. This work demonstrates the effectiveness of SHI irradiation in engineering defects within MoS2 nanoflakes, leading to significantly improved NO2 gas-sensing performance. This approach offers a promising avenue for developing next-generation TMD-based gas sensors with enhanced sensitivity, response times, and stability.

Selective CO2 Reduction Electrocatalysis Using AgCu Nanoalloys Prepared by a "Host-Guest" Method.

Multimetallic nanoalloy catalysts have attracted considerable interest for enhancing the efficiency and selectivity of many electrochemically driven chemical processes. However, the preparation of homogeneous bimetallic alloy nanoparticles remains a challenge. Here, we present a room-temperature and scalable, host-guest approach for synthesis of dilute Cu in Ag alloy nanoparticles. In this approach, an ionic silver bromide precursor harboring exogenous Cu cations is reduced to yield ∼20 nm diameter AgCu alloy nanoparticles wherein the % Cu loading can be tuned precisely. AgCu nanoparticles with a 5% nominal loading of Cu exhibit peak activity (-0.23 mA/cm2 normalized partial current density) and selectivity (83.2% faradaic efficiency) for CO product formation from electrocatalytic reduction of CO2 at mild overpotentials. These AgCu nanoalloys exhibit a higher mass activity compared to Ag- and Cu-containing nanomaterials used for similar electrocatalytic transformations. Our host-guest synthesis platform holds promise for production of other nanoalloys with relevance in electrocatalysis and optics.

Predictive calculation of the stability constants of silver(I) ion with pyridine and 2,2′-bipyridyl in a solvent environment

In the present study, the stability constants of silver(I) coordination compounds with 2,2′-bipyridyl (bpy, L) in mixed methanol–acetonitrile solvents (MeOH-AN, χAN = 0.0 ÷ 1.0 mol fr.) were determined by the potentiometric method at 25.0 °C. The influence of reagents solvation on the change in stability of [Ag(bpy)]+ and [Ag(bpy)2]+ complexes upon changing the composition of the solvent MeOH→(MeOH-AN) was analyzed. It has been established that the determining factor in the shift of the complex formation equilibrium along the first and second steps of coordination with a change in the composition of the solvent is the contribution from the central ion resolvation. The obtained results and data on the thermodynamics of complex formation reactions of Ag+ with bpy and pyridine (py, L) in a few binary non-aqueous solvents were compared. The possibility of carrying out an estimated calculation of the stability constants of [Ag(L)]+ in non-aqueous solvents was confirmed.

In Vitro Assessment of Gallium Nanoalloy Hydrogels for Antimicrobial and Wound Healing Applications.

Chronic and recurring wounds pose a significant challenge in modern healthcare, leading to substantial morbidity. These wounds allow pathogens to colonize, potentially resulting in local and systemic infections. Current interventions need to be revised and become increasingly less reliable due to the emergence of antibiotic resistance. In the present study, we aim to address these issues by fabricating hydrogels impregnated with gallium-based nanoalloys for their antimicrobial activity. Gallium liquid metal nanoparticles (approximately 100 nm in diameter) were alloyed in different combinations with bismuth and silver ions through a galvanic replacement reaction. These multimetallic hydrogels showed favorable antibacterial activity against the Gram-positive Staphylococcus aureus and the Gram-negative Pseudomonas aeruginosa, as observed with fluorescence microscopy and inhibition assays. The multimetallic hydrogels showed no toxicity against murine macrophages or human dermal fibroblasts and enhanced in vitro wound healing. The development of these innovative gallium-based hydrogels represents a promising strategy to combat chronic wounds and their associated complications, offering an effective alternative to current antimicrobial treatments amidst rising antibiotic resistance.

Optical, dielectric, and rheological properties of EG-Al2O3/AgNO3 nanofluids: Insights and advances in multifunctional materials for soft device technologies

Nanofluids (NFs) of fascinating multifunctional properties are the advanced materials highly admired in emerging soft device technologies. In this innovative research, we explored the detailed optical, dielectric, and rheological properties of silver ions conducting green NFs. These NFs comprise ethylene glycol (EG) as viscous base fluid, suspension of a fixed amount (0.02 wt%) aluminum oxide (Al2O3) nanoparticles for high performance thermal conductor, and addition of silver nitrate (AgNO3) salt as the ionic component of varying amounts ranging from 0.2 to 2.0 wt% are prepared and investigated. The detailed analysis of 200–800 nm wavelength range ultraviolet–visible (UV–Vis) absorbance spectra of these EG–Al2O3/AgNO3 based NFs demonstrated their significant photosensitivity character in the visible region, radiations shielding performance in the UV region, and trio energy band gaps in a wide semiconducting range from 2.4 to 4.9 eV which are found adequately tunable with the AgNO3 concentrations. The high static dielectric permittivity (εs ≈ 40) of these polar NFs, at 298.15 K, showed a marginal change with the variation in AgNO3 concentrations confirming a little alteration in the parallel aligned dipole ordering of hydrogen bonded EG molecular network beside the ion-molecules-nanoparticle interactions and formation of ion-dipole complexes (coordinative interaction). The electrical conductivity of EG–Al2O3 NF increased by three orders of magnitude i.e., from 10−6 to 10−3 S/cm, at the initial addition of 0.2 wt% AgNO3 in it and then, exhibited almost a linear increase with further increasing the salt concentrations up to 2.0 wt% realizes them promising ionic nanofluids. Rheological investigations on these NF samples, at 298.15 K, validate their Newtonian behaviour with a high dynamic viscosity of 14 mPa s. These experimental findings highlight the multifunctional characteristics of EG–Al2O3/AgNO3 nanofluids which could be utilized in heat transfer, solar energy harvesting/storage, and the development of next-generation iontronic and optoelectronic devices and silver ion conducting biomedical sensors.

Restricted Intramolecular Rotation: A Dual Fluorescence Response to Hg2+ Quenching and Ag+ Enhancement in Live Rhizoctonia Solani Cells.

A novel imidazo[1,2-a]pyridine derivative probe (R) was designed, synthesized, and characterized via various characterization techniques, such as ESI-MS, 1H NMR, 13C NMR, and Dept-135 NMR. The data obtained from single-crystal XRD reveal that probe R has a coplanar configuration and is part of the monoclinic crystal system, designated the P2(1)/n space group. The fluorescence of (R) is further enhanced by silver (I) ions. On the other hand, Hg2+ significantly quenches the fluorescence of probe R. The presence of other common metal ions does not influence the fluorescence of probe R in the CH3CN: H2O (1:1) mixture, as they neither increase nor quench it. From the fluorescence enhancement data, the low detection limit (LOD) for Ag + ions was determined to be 1.24 × 10- 8 M, whereas the quenching caused by Hg2+ resulted in an LOD of 5.69 × 10- 9 M. The complex of probe R with Ag+/Hg2+ exhibited a 1:1 stoichiometry, as confirmed by mass spectrometry and a Job plot. Single-crystal XRD analysis of R and its complex with Hg2+ revealed a loss of coplanarity, which confirmed their nonfluorescent behavior. We present a promising application of probe R in visualizing living Rhizoctonia oryzae cells exposed to silver (I) and mercury (II) ions.

Biotechnological potential of silver nanoparticles synthesized by green method to control phytopathogenic bacteria: contributions from a proteomic analysis.

Silver nanoparticles (AgNPs) synthesized through green synthesis routes are widely used as antimicrobial agents due to their advantages such as biocompatibility, stability, sustainability, speed and cost-effectiveness. Although AgNPs appear to be more potent than silver ions, the mechanisms related to their antibacterial activity are not yet fully understood. The most common proposed mechanism of AgNPs' toxicity so far is the release of silver ions and/or specific functions of the particles. In this context, the present study aimed to investigate the mechanisms of action of AgNPs synthesized using noni fruit peels (Morinda citrifolia) against the phytopathogen Xanthomonas campestris pv. campestris (Xcc) through proteomics. Xcc was treated with AgNPs (32 µM), AgNO3 (32 µM), or received no treatment (Ctrl - control condition), and its proteomic response was comprehensively characterized to elucidate the antimicrobial mechanisms of AgNPs in the phytopathogenic microorganism. A total of 352 differentially abundant proteins were identified. Most proteins were regulated in the AgNPs × Ctrl and AgNPs × AgNO3 comparisons/conditions. When Xcc treated with 32 µM AgNPs were compared to controls, the results showed 134 differentially abundant proteins, including 107 increased and 27 decreased proteins. In contrast, when Xcc treated with 32 µM AgNO3 were compared to Ctrl, the results showed only 14 differentially abundant proteins, including 10 increased proteins and 4 decreased proteins. Finally, when Xcc treated with 32 µM AgNPs were compared to Xcc treated with 32 µM AgNO3, the results showed 204 differentially abundant proteins, including 75 increased proteins and 129 decreased proteins. Gene ontology enrichment analysis revealed that most of the increased proteins were involved in important biological processes such as metal ion homeostasis, detoxification, membrane organization, metabolic processes related to amino acids and carbohydrates, lipid metabolic processes, proteolysis, transmembrane transport, and others. The AgNPs used in this study demonstrated effective antimicrobial activity against the phytopathogenic bacteria Xcc. Furthermore, the obtained results contribute to a better understanding of the mechanisms of action of AgNPs in Xcc and may aid in the development of strategies to control Xcc in brassica.

Dual-Function Femtosecond Laser: β-TCP Structuring and AgNP Synthesis via Photoreduction with Azorean Green Tea for Enhanced Osteointegration and Antibacterial Properties.

β-Tricalcium phosphate (β-TCP) is a well-established biomaterial for bone regeneration, highly regarded for its biocompatibility and osteoconductivity. However, its clinical efficacy is often compromised by susceptibility to bacterial infections. In this study, we address this limitation by integrating femtosecond (fs)-laser processing with the concurrent synthesis of silver nanoparticles (AgNPs) mediated by Azorean green tea leaf extract (GTLE), which is known for its rich antioxidant and anti-inflammatory properties. The fs laser was employed to modify the surface of β-TCP scaffolds by varying scanning velocities, fluences, and patterns. The resulting patterns, formed at lower scanning velocities, display organized nanostructures, along with enhanced roughness and wettability, as characterized by Scanning Electron Microscopy (SEM), optical profilometry, and contact angle measurements. Concurrently, the femtosecond laser facilitated the photoreduction of silver ions in the presence of GTLE, enabling the efficient synthesis of small, spherical AgNPs, as confirmed by UV-vis spectroscopy, Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The resulting AgNP-embedded β-TCP scaffolds exhibited a significantly improved cell viability and elongation of human bone marrow mesenchymal stem cells (hBM-MSCs), alongside significant antibacterial activity against Staphylococcus aureus (S. aureus). This study underscores the transformative potential of combining femtosecond laser surface modification with GTLE-mediated AgNP synthesis, presenting a novel and effective strategy for enhancing the performance of β-TCP scaffolds in bone-tissue engineering.

Solution plasma synthesis of nitrogen-doped carbon dots from glucosamines: Comparative fluorescence modulation for dopamine detection

The intriguing fluorescence characteristics of carbon dots (CDs) have led to many sensor applications, particularly for dopamine (DA), a molecule linked to various diseases. This study prepares CDs from glucose and glucosamine (nitrogen-free and nitrogen-containing precursors) using a simple solution plasma process (SPP). We explore how nitrogen elements and counterions in glucosamine (hydrochloride and sulfate) affect CD properties and their ability to modulate fluorescence for DA detection. Glucosamine offers three advantages over glucose: (i) single-step CD synthesis via SPP, (ii) enhanced fluorescence of CDs, and (iii) improved fluorescence response to DA. We investigate the DA detection capabilities of N,S-CDs (from glucosamine sulfate) and N,Cl-CDs (from glucosamine hydrochloride). Both can sense DA with distinct photoluminescence responses. N,S-CDs show selectivity and fluorescence brightening upon DA interaction, with a detection limit of 33.05 μM. N,Cl-CDs demonstrate higher sensitivity with a lower detection limit of 0.1212 μM through fluorescence quenching. Silver ions (Ag+) may also contribute to N,Cl-CDs quenching; however, the observed color change to gray due to silver nanoparticle (AgNP) formation helps pinpoint the quenching substance. The varied photoluminescence responses arise from different surface functional groups: N,S-CDs have amino-rich surfaces, while N,Cl-CDs have conjugated carbonyl-rich surfaces. This study illustrates the mechanisms of DA detection and AgNP formation, suggesting the potential of CDs in medical diagnostics as selective tools for disease diagnosis. Additionally, we compare the DA sensing methodology of our CDs with existing literature, highlighting the advantages of our sensor.