Surface Modification Of Nanoparticles Research Articles

Efficacy Assessment of Sulfated Flavanol Functionalized Silver Nanoparticles against MCF-7 Breast Cancer

Aim: The present research work aims to formulate a cost-effective and less toxic drug for specific and selective delivery at the tumor site. Background: Existing therapeutics, such as chemo, surgery, etc., for fast-paced MCF-7 breast cancer, still face challenges, especially due to their toxic side effects. The unique properties of metal nanoparticles embedded in anti-oxidant plant polymers have sparked great interest in the formulation of less toxic-targeted drugs for cancer cure. Objective: The present work aims to synthesize a targeted formulation of colloidal nanosilver by surface engineering of silver nanoparticles using plant polymers in electrolytic deposition technique, developed indigenously at the institute lab. Methods: A current is passed through an elctrolyte, AgNO3, which splits it into ions. The positive ions of Ag deposit over LDPE wrapped carbon cathode and negative ion, NO3, is liberated. Ag+ ions get capped in-situ. These surface-modified silver nanoparticles formulate a colloidal solution. UV-visible and FTIR spectroscopy, TEM-EDX, and XRD were used to validate asprepared formulation and in vivo human tumor xenograft model in NOD-SCID mouse for efficacy against MCF-7 breast cancer. Results: The as-synthesized formulation consists of pure spherical poly-dispersed silver nanoparticles of average size 5.4 nm, coated with sulphated flavanols. The efficacy evaluation reported that it significantly, T/C = 0.53, reduced tumor volumes with a 100% survival rate and change in animal body weight <4 gms. Conclusion: The as-synthesized formulation can be used as a potential neo-adjuvant or adjuvant drug along with existing therapeutics for MCF-7 breast cancer, significantly reducing the toxicity and cost.

Specific surface-modified iron oxide nanoparticles trigger complement-dependent innate and adaptive antileukaemia immunity

Considerable advances have been achieved in the application of nanomaterials for immunotherapies, yet the precise immune effects induced by protein corona remain elusive. Here, we explore the formation mechanism and immune regulation process of protein corona in acute myeloid leukaemia (AML) mouse models using commercialized iron oxide nanoparticles (IONPs), with different surface modifications, including an FDA-approved variant. Using macrophages depleted or Complement Component 3 (C3) knockout mice, we demonstrate that carboxymethyl dextran-coated IONP (IONP-COOH) reduces leukaemia burden. Mechanistically, IONP-COOH indirectly binds to C3b after activating the complement alternative pathway, subsequently enhancing phagocytosis of macrophages and activating adaptive immunity mediated by complement corona. While aminated dextran-coated IONPs directly absorb C3b and activate the lectin pathway, leading to immune cell exhaustion. Our findings suggest that IONP-COOH may serve as an immune activator for AML treatment, offering a promising approach to developing therapeutic nanomaterials by leveraging surface chemistry to enhance immunotherapy.

Novel synthesis of reduced PdO-WO3 hybrids for enhanced photoelectrochemical water splitting

In this study, a novel synthesis approach for WO3 nanoparticles and their hybrids is proposed, followed by an investigation of their photoelectrochemical performance for water splitting applications. The surface modification of WO3 nanoparticles is carried out by immersing them in a Pd precursor solution, followed by calcination to obtain PdO-WO3 hybrid nanoparticles. Subsequently, the PdO-WO3 is reduced in a hydrogen (H2) environment to prepare PdOx-WO3-y hybrid material. XPS analysis revealed that H2 reduction converts residual metallic Pd to PdH and simultaneously generates oxygen vacancy defects in WO3 hybrid nanoparticles, as confirmed by EPR analysis. Additionally, TPR analysis further confirms the H2-induced reduction in the PdO-WO3 hybrid at a lowered temperature of 150 °C. The optical band gap energy of PdOx-WO3-y hybrid nanoparticles is slightly reduced (by 0.06 eV) compared to that of the PdO-WO3 reference sample. Photoelectrochemical measurements were conducted to assess the impact of these tailored modifications on the performance of conventional PdO-WO3 nanoparticles. The reduced PdOx-WO3-y catalyst exhibits an approximatly ∼22 % improvement in incident photon-to-current conversion efficiency (IPCE), over the unreduced PdO-WO3. The PEC efficiency improvement was attributed to the composite electronic structure changes introduced during the annealing process. Mott-Schottky measurements confirm that the reductive treatment consolidates the material’s two distinct flat band potentials (Efb) into with a single intermediate energy level and increases the charge carrier concentration. This study presents a straightforward method to generate oxygen vacancy defects in hybrid metal oxides and provides a convenient method for band gap engineering for photoelectrocatalytic applications.

Eco-friendly, high-effective, and biocompatible sorbent based on specially designed hydroxyapatite nanoparticles for wastewater treatment from non-ionic surfactants

A new approach to the development of sorbents based on surface-modified hydroxyapatite (HAp) nanoparticles (NPs) for extraction of nonionic surfactants is proposed and tested. The essence of the approach is the building HAp NPs through a non-classical oriented attachment (OA) mechanism from smaller NPs under hydrothermal treatment. Based on characterization data and quantum-chemical calculations, a possible mechanism for final NPs formation is suggested. An additive of ammonium nitrate was used as a source of ammonium ions to specifically regulate the process of OA impacting the size of final NPs, the increase of additive amount resulted in the final NPs size decrease. An original procedure for NPs surface modification by fatty acids in order to create required for sorption of nonionic surfactants combination of hydrophobic and hydrophilic areas was developed. Obtained NPs were used as sorbents for extraction of nonionic surfactant Triton X-100 from aqueous solutions, including solutions based on water taken from city water channel, showing extraction efficiency up to 100 %. The extraction efficiency is determined not only by the fatty acid used for surface modification, but also by the location of modifier on NP surface.

Rate-Controlled Washing of Surface-Modified Nanoparticles Using Rationally Designed Supercritical CO2 Media.

In practical applications of surface-modified nanoparticles (NPs), the washing stage has a number of challenges, such as insufficient washing, long treatment time, and various waste liquors. Cosolvent-enhanced supercritical CO2 (scCO2) is an appealing solvent system for complete, rapid, and eco-friendly washing owing to its high diffusivity and recyclability. In this paper, we report a rapid washing guideline for surface-modified NPs using ethanol-enhanced scCO2. Kinetic analysis was performed on the washing behavior of oleic acid-modified NPs mixed with various modifiers (C10 to C18 fatty acids) at 40 °C and 20.0 MPa while designing scCO2 media based on rationally estimated modifier solubilities. Notably, the scCO2 medium showed superior washing rates to that of ethanol for various modifiers with a wide range of solubilities in scCO2. The washing rate was dependent on solubility and could be organized into two regions, with a threshold value of 0.016 mol kg-1: solubility/diffusivity-controlled and diffusivity-controlled washing. These findings provide valuable guidelines for designing cosolvent-enhanced scCO2 media for the rapid washing of surface-modified NPs.

Enhanced Electrocaloric Effect of PVDF-based Polymer Composite with Surface Modified AlN.

Poly(vinylidenefluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) relaxor ferroelectric polymer exhibits a modest electrocaloric effect (ECE) at a low electric field near room temperature and a low thermal conductivity. The low thermal conductivity causes poor heat transfer when the terpolymer is used as a cooling device, even when the ECE of the polymer is substantial. By incorporating aluminum nitride (AlN) nanoparticles, which possess high thermal conductivity and good electrical insulation properties, into polymer matrices, we can enhance both the thermal conductivity and the ECE. However, weak bonding at the AlN-polymer interface can lead to a reduced breakdown electric field. Therefore, surface modification of AlN nanoparticles is performed to strengthen the chemical bonding between AlN and the terpolymer, thereby increasing the breakdown electric field. Following the addition of surface-modified nanoparticles, the breakdown electric field of the composite films remained around 240 MV/m, which is comparable to that of the pristine polymer film. Furthermore, the ECE and thermal conductivity were improved by 44% and 55%, respectively. We found three factors influencing the ECE, including the interface effect, the change in ferroelectric-paraelectric phase transition behavior, and the Joule heating effect. To assess the interfacial effect on the ECE, composite films with AlN particles of four different sizes were prepared. It was found that as the size of the nanoparticles increased, which resulted in a decreased interface area, the ECE decreased correspondingly. This finding further confirms the significant impact of the interface area in the composites on the ECE.

Navigating the nano-bio immune interface: advancements and challenges in CNS nanotherapeutics.

In recent years, significant advancements have been made in utilizing nanoparticles (NPs) to modulate immune responses within the central nervous system (CNS), offering new opportunities for nanotherapeutic interventions in neurological disorders. NPs can serve as carriers for immunomodulatory agents or platforms for delivering nucleic acid-based therapeutics to regulate gene expression and modulate immune responses. Several studies have demonstrated the efficacy of NP-mediated immune modulation in preclinical models of neurological diseases, including multiple sclerosis, stroke, Alzheimer's disease, and Parkinson's disease. While challenges remain, advancements in NPs engineering and design have led to the development of NPs using diverse strategies to overcome these challenges. The nano-bio interface with the immune system is key in the conceptualization of NPs to efficiently act as nanotherapeutics in the CNS. The biomolecular corona plays a pivotal role in dictating NPs behavior and immune recognition within the CNS, giving researchers the opportunity to optimize NPs design and surface modifications to minimize immunogenicity and enhance biocompatibility. Here, we review how NPs interact with the CNS immune system, focusing on immunosurveillance of NPs, NP-induced immune reprogramming and the impact of the biomolecular corona on NPs behavior in CNS immune responses. The integration of NPs into CNS nanotherapeutics offers promising opportunities for addressing the complex challenges of acute and chronic neurological conditions and pathologies, also in the context of preventive and rehabilitative medicine. By harnessing the nano-bio immune interface and understanding the significance of the biomolecular corona, researchers can develop targeted, safe, and effective nanotherapeutic interventions for a wide range of CNS disorders to improve treatment and rehabilitation. These advancements have the potential to revolutionize the treatment landscape of neurological diseases, offering promising solutions for improved patient care and quality of life in the future.

Eco-friendly synthesis and surface modification of ZnO nanoparticles using Pueraria montana root extract: enhanced photocatalytic performance with trisodium pyrophosphate

ABSTRACT The synthesis of zinc oxide (ZnO) nanoparticles using Pueraria montana (kudzu) plant extracts highlights advancements in green nanotechnology. This study explores the use of Pueraria montana roots, rich in phytochemicals such as phenols, terpenoids and flavonoids, which serve as natural reducing and stabilizing agents for nanoparticle synthesis. The eco-friendly production and surface modification of ZnO nanoparticles were achieved using these plant extracts, enhancing their photocatalytic performance with trisodium pyrophosphate (TSPP).Characterization techniques, including XRD, TEM, and FE-SEM, confirmed the nanoparticles’ crystalline structure, with a BET surface area of 14.01 m²/g and a type II adsorption isotherm. The synthesized nanoparticles exhibited exceptional dye degradation capabilities, achieving 99.9% removal of malachite green (MG) and 97.78% for aniline blue (AB). Kinetic analysis revealed a steady-state rate constant (k) of 2 × 10⁻⁴ min⁻¹ for MG where as the response rate constant(k) for the photocatalytic degradation of AB using modified ZnO nanostructures was 3.0 × 10−3 min−1 allowing near-total dye removal within 600 minutes for MG and 350 min for AB . Adsorption studies were well described by Langmuir and Freundlich isotherms, indicating maximum adsorption capacities of 59.7 mg/g for MG and 61.2 mg/g for AB. Surface modification with TSPP improved charge carrier separation and enhanced the generation of reactive oxygen species under UV exposure, further increasing dye degradation efficiency.Statistical analysis indicated high reproducibility, with close mean adsorption values of 99.125 for MG and 97.3125 for AB, supported by small standard deviations. The findings affirm the potential of using Pueraria montana in synthesizing efficient photocatalysts, providing a sustainable and cost-effective approach for water treatment applications. Overall, this research underscores the effectiveness of plant-based materials in advancing eco-friendly nanotechnology solutions.

Surface modification of Au nanoparticles with porous carbon microsheets/Bi2S3 for enhanced electrochemical monitoring of hazardous sulfamethoxazole

Surface modification of Au nanoparticles with porous carbon microsheets/Bi2S3 for enhanced electrochemical monitoring of hazardous sulfamethoxazole

Surface-modified ZnO nanoparticles for enhanced environmental and biomedical performance

The present study explores the synthesis of cetyltrimethylammonium bromide-modified zinc oxide nanoparticles (CTAB: ZnO NPs) via a precipitation-cum-hydrothermal route, optimizing their multifunctional capabilities for photocatalytic dye degradation and antibacterial applications. The synthesized ZnO NPs exhibit a wurtzite hexagonal structure, as confirmed by X-ray diffraction (XRD), with an average crystallite size of 47.12 nm, refined through Williamson-Hall (107.8 nm) and modified Debye-Scherrer (41 nm) analyses to account for lattice strain effects. UV-visible spectroscopy reveals a sharp absorption peak at 430 nm, with a corresponding band gap of 3.2 eV, indicative of strong quantum confinement effects. High-resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) confirm the quasi-spherical morphology with minimal agglomeration, while energy-dispersive X-ray spectroscopy (EDX) validates the purity of the ZnO composition. Photocatalytic investigations demonstrate a remarkable degradation efficiency of 100% for reactive blue-81 (RB-81) dye under UV irradiation within 1.3 hours, with a kinetic reaction rate of 5.71 × 102 μmol·g⁻1·h⁻1. Quantum yield (QY) and space-time yield (STY) values of 2.53 × 10⁻⁴ molecules photon⁻1 and 1.27 × 10⁻⁵ molecules photon⁻1·mg⁻1, respectively, highlight the superior photonic utilization efficiency compared to conventional TiO₂-based photocatalysts. Antibacterial studies using the agar well diffusion method reveal significant inhibition zones of up to 3.42 cm and 2.14 cm for Staphylococcus aureus and Pseudomonas aeruginosa, respectively, demonstrating potent antibacterial activity. The findings indicate that CTAB: ZnO NPs not only enhance photocatalytic degradation and antibacterial efficacy but also offer scalable potential for environmental remediation and biomedical applications.

Fabrication and Characterization of Biocompatible Multilayered Elastomer Hybrid with Enhanced Water Permeation Resistance for Packaging of Implantable Biomedical Devices.

This study presents the synthesis and characterization of hexadecyl-modified SiO2 (HD-SiO2) nanoparticles and their application in the fabrication of a multilayered elastomer hybrid sheet to enhance water resistance in implantable biomedical devices. The surface modification of SiO2 nanoparticles was confirmed via FT-IR and TGA analyses, showing the successful grafting of hydrophobic hexadecyl groups. FE-SEM and DLS analyses revealed spherical HD-SiO2 nanoparticles with an average size of 360 nm. A multilayered elastomer hybrid sheet, consisting of a PDMS-based circuit-protecting body, a water resistance layer of HD-SiO2, a planarization layer, and a biocompatible layer of polydopamine, was fabricated and characterized. The water resistance layer exhibited superhydrophobic properties, with a water contact angle of 154.7° and a 27% reduction in water vapor transmission rate (WVTR) compared to the circuit-protecting body alone. The device packaged with both the circuit-protecting body and water resistance layer demonstrated a tenfold increase in operational lifespan in water medium compared to the device without the water resistance layer. Cytotoxicity and cell proliferation tests on human dermal fibroblast cells (HDFn) confirmed the biocompatibility of the multilayered sheet, with no significant cytotoxicity observed over 48 h.

Stability Assessment Through Dynamic Light Scattering and Rheological Study of Hexanoic Acid-Surface-Modified Cerium Oxide Nanoparticles in Cyclohexane at Low Concentration

The stability of 1wt% cerium oxide (CeO2) nanoparticles in cyclohexane is assessed in this paper. To do so, first, n-hexanoic acid (C6-) surface-modified CeO2 nanoparticles were synthesized by heating the aqueous Ce(OH)4 suspension at 400 °C and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high regulation transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). XRD pattern indicated the crystalline structure and TEM showed the cubic shape of the synthesized CeO2 nanoparticles with an average size of 4.5 nm. Next, 1 wt% CeO2–cyclohexane dispersion (nanofluids) was prepared simply by dispersing the required amounts of CeO2 nanoparticles in cyclohexane. Finally, the stability of CeO2–cyclohexane was assessed by dynamic light scattering (DLS) and rheological study. DLS measurement revealed that the 1wt% CeO2–cyclohexane nanofluid has good dispersibility with a small DLS diameter (~6 nm) comparable to that of the pristine particle diameter measured by TEM. Also, the rheology study depicted the Newtonian behavior of prepared nanofluids which indicated its excellent stability. Jagannath University Journal of Science, Volume 11, Number 1, June 2024, pp. 23−30

A 326 nm pure ultraviolet light sources achieved in a Ga[formula omitted]O[formula omitted] microwire heterojunction through interface optimization and surface-modification

Low-dimensional Ga2O3 single-crystals have caused widespread attentions in the potential of developing ultraviolet light sources due to its ultrabroad bandgap, low-budget, high thermally stable, high breakdown voltage and others. Herein, we exhibit a significant route to construct one-dimensional Ga2O3 microwire heterojunction deep-ultraviolet light-emitting diode (LED). The resulting electroluminescence is positioned at 326 nm with a narrow linewidth of about 22.5 nm, which is the shortest wavelengths once published for the Ga2O3-related light sources. In the well-fabricated LED, an intermediate AlN layer enables appropriately to manipulate band alignment of n-Ga2O3/p-GaN heterojunction, thus achieving efficient confinement of electron–holes spreading and radiative recombination within the Ga2O3 microwire active medium. Benefited from surface-modified Pt nanoparticles, the LED’s electroluminescence efficiency and brightness can be plasmonically boosted. More importantly, the peak energy at 3.8 eV obtained under forward bias, which is smaller than the Ga2O3 bandgap, could be resulted from radiative recombination of weakly-bounded electron–holes inside the Ga2O3 microwires. Therefore, the Ga2O3 monocrystalline wires synthesized using high-temperature carbothermal reduction, are expected as promising-looking candidates to develop environmentally friendly, easy miniaturization, highly-stable deep-ultraviolet light sources and photonic devices.

Surface-Modified Iron Oxide Nanoparticles with Natural Biopolymers for Magnetic Hyperthermia: Effect of Reducing Agents and Type of Biopolymers

Magnetic fluid hyperthermia, a minimally invasive localized therapy that uses heat generated by magnetic nanoparticles under an AC magnetic field, is a complementary approach for cancer treatment that is excellent due to its advantages of being noninvasive and addressing only the affected region. Still, its use as a stand-alone therapy is hindered by the simultaneous requirement of nanoparticle biocompatibility, good heating efficiency, and physiological safe dose. To overcome these limits, the biocompatible magnetic nanoparticles’ heating efficiency must be optimized. Iron oxide nanoparticles are accepted as the more biocompatible magnetic nanoparticles available. Therefore, in this work, superparamagnetic iron oxide nanoparticles were synthesized by a low-cost coprecipitation method and modified with starch and gum to increase their heating efficiency and compatibility with living tissues. Two different reducing agents, sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH), were used to compare their influence. The X-ray diffraction results indicate the formation of a single magnetite/maghemite phase in all cases, with the particle size distribution depending on the coating and reducing agent. Citric acid functionalized water-based ferrofluids were also prepared to study the heating efficiency of the nanoparticles under a magnetic field with a 274 kHz frequency and a 14 kAm−1 amplitude. The samples prepared with NaOH display a higher specific loss power (SLP) compared to the ones prepared with NH4OH. The SLP value of 72 Wg−1 for the magnetic nanoparticles coated with a combination of starch and gum arabic, corresponding to an intrinsic loss power (ILP) of 2.60 nWg−1, indicates that they are potential materials for magnetic hyperthermia therapy.

Surface modification of titania nanoparticles with BSA engineered coating: Investigation of antimicrobial and anticancer activities

Intensive investigate in the scientific community focuses on designing and altering nanosystem surfaces with biomolecules to create more biocompatible and stable systems, leveraging their unique structure. The current work reports the synthesis of an ultrafine titania nano-bio-corona system (TNPs-BSA-PyBA) by surface functionalization of titania nanoparticles (TNPs) with 1-pyrene butyric acid (PyBA) coupled with bovine serum albumin (BSA). This biocompatible photocatalytic system was studied using Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Visible), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal analysis, zeta potential and fluorescence emission studies. The photocatalytic antimicrobial properties of synthesized TNPs and TNPs-BSA-PyBA system were evaluated against various antibiotic-resistant microbial strains via the well diffusion method, and the result showed that the surface-modified titania nanoparticles showed an enhanced bacteriostatic effect against various bacterial and fungal strains. Also, in vitro cytotoxic studies and cell viability of the TNPs-BSA-PyBA nanocomposite system were studied by the trypan blue exclusion method on Dalton’s Lymphoma Ascites cells as well as normal cells. The cytotoxicity investigations demonstrated that the TNPs-BSA-PyBA system selectively targeted and destroyed cancer cells, with the effectiveness varying depending on the dosage.

Porous polyimide composite films containing mesoporous hollow silica nanospheres with ultralow dielectric constant and dissipation loss

Porous polyimide hybrid films with ultralow dielectric constant and dissipation loss were synthesized during chemical imidization and rapid evaporation of polymer solutions. Polyimide (PI) of bis(4-aminophenyl)-1,4-diisopropylbenzene (BISP) and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) were synthesized in N-methylpyrrolidinone (NMP) to yield the corresponding poly(amic acid)s (PAA)s, which were then chemically imidized. To reduce the dielectric properties of the porous PI films, amine-functionalized, surface-modified hollow silica nanoparticles (AHNS) with various sizes from 100 nm to 1 μm, prepared via sol-gel process, were added with PAA at 3, 5, or 10 % weight content, followed by chemical imidization to produce the porous PI/AHNS films. To avoid the high-volume shrinkage of wet gels and maintain the high porosity of the PI with low polarizability, AHNS nanoparticles were added to the porous structure of the PI xerogels as a physical crosslinker. The polyimide hybrid film with 10 nm AHNS nanoparticles at 10 % weight content showed a dielectric constant of 1.151 and a dissipation rate of 0.001 at a frequency of 10 GHz.

Aluminum phthalocyanine tetrasulfonate conjugated to surface-modified Iron oxide nanoparticles as a magnetic targeting platform for photodynamic therapy of Ehrlich tumor-bearing mice

BackgroundPhotodynamic therapy (PDT) is a targeted treatment option for cancers that are non-responding to ordinary anticancer therapies. It involves activating a photosensitizer with a light source of a specific wavelength to destroy targeted cells and their surrounding vasculature. Aluminum phthalocyanine tetra sulfonate (AlPcS4) has gained attention as a second-generation photosensitizer for its strong absorption in the red-light region. AlPcS4 can be conjugated to magnetic iron oxide nanoparticles (IONs) to provide targeted drug delivery to the tumor cells while reducing its undesired effect on healthy tissues in other body parts. MethodsMagnetic glutamine functionalized iron oxide nanocomposites loaded with AlPcS4 (IONs-NH2-AlPcS4) were synthesized via the co-precipitation method. The conjugate (IONs-NH2-AlPcS4) was characterized by TEM, Zeta potential, DLS, FTIR, and UV–VIS absorption spectroscopy. Furthermore, its photodynamic activity was investigated using albino mice with induced Ehrlich solid tumors. ResultsAlPcS4 was successfully conjugated to IONs-NH2 with a high loading efficiency of 54±2%. The synthesized conjugate exhibited a spherical shape, with 7 ± 2 nm particle size. The In vivo experiment revealed that the albino mice with induced Ehrlich solid tumor that were treated by combined PDT and magnetic targeting conjugate exhibited significant tumor regression and notably higher levels of necrotic tissue compared to the animals in other groups. ConclusionPDT mediated by magnetic targeting significantly inhibited tumor growth with minimal adverse effects, indicating its great potential as a promising strategy for solid cancer treatment.

The development and evaluation of chitosan-coated enzyme magnetic nanoparticles for cellulose hydrolysis

The recycling capability, colloidal and thermal stability of exo-cellulase, endo-cellulase, and β-glucosidases with magnetic particles (MNPs) were evaluated. Co-precipitation and oxidation of Fe(OH)2 methods were used to fabricate magnetic nanoparticles. Three different enzymes were covalently bound to the surface of MNPs using 3-(aminopropyl) triethoxysilane (APTES) and a common protein crosslinking agent, glutaraldehyde. To evaluate the increase in colloidal dispersion stability, chitosan-coating was applied on MNPs and evaluated through particle settlement tests. The results showed that the chitosan-coated MNPs had 3.7 times higher colloidal dispersion stability than the bare MNPs. X-ray photoelectron spectroscopy (XPS) confirmed each magnetic nanoparticle surface modification step and successful enzyme binding. The optimum bioconjugate ratio in exo-cellulase, endo-cellulase, and β-glucosidases was evaluated, and having a high endo-cellulase bioconjugate in the reaction produced the highest glucose. The bioconjugates showed superior glucose productivity 39.4% at 65°C and 22.2% at 88°C in which the native enzyme is inactivated completely after 5 h of exposure. Recycling stability studies showed approximately 78% of activity was retained after 10 cycles and 32% of activity was retained after 20 cycles. The bioconjugates demonstrated equivalent total product conversions as a single reaction of an equivalent amount of the native enzyme after the 10th cycle this work introduces a novel method for covalently binding individual exo-cellulase, endo-cellulase, and β-glucosidases. These bioconjugates showed superior thermal stability and recyclability. It was also demonstrated that chitosan coating significantly improves the colloidal dispersion stability of bioconjugates. Thus this work validates the use of enzyme-MNP bioconjugates to effectively glucose production and promising technique for eventual continuous biological processes.

Optimization of Mesoporous Silica Nanoparticles of Silymarin through Statistical Design Experiment and Surface Modification by APTES

ABSTRACT: The major goal of this study was to create surface-modified mesoporous silica nanoparticles (MSN) of Silymarin, which has a short half-life and requires regular dosing due to first-pass metabolism. MSN was prepared by cost effective Sol-Gel method, functionalized by (3-Aminoprpyl) triethoxysilane (3-APTES). Evaluated and compared the Silymarin-loaded MSN and APTES functionalized MSN for drug loading, in-vitro dissolution, particle size, surface morphology, surface area, pore size and volume. The percent drug loading and encapsulation efficiency of APTES-functionalized MSN were found to be 92.50±0.72 % percent and 93.20±0.13 %, respectively, which showed a higher value in APTES-functionalized MSN as compared to Silymarin-loaded MSN. Drug release of APTES-functionalized MSN was 92.15 0.03%, which was more as compared to silymarin-loaded MSN. XRD showed that after functionalization silymarin changed from crystalline to amorphous form. SEM indicates that MSN was formed in a spherical shape with particle size of 196.7nm. The BET analysis proved that the nanoparticles had a larger surface area, which was reduced after drug loading and functionalization. Also, the pore size was increased and the pore volume was reduced after functionalization, indicating the incorporation of silymarin. The results suggested that the functionalization might successfully increase adsorption capacity, larger surface area, and increased encapsulation. Mesoporous silica nanoparticles also showed a greater impact on dissolution.

Comparative study on the effect of surface-modified nanoparticles on PCM for solar energy applications

Comparative study on the effect of surface-modified nanoparticles on PCM for solar energy applications