Mesoporous silica nanoparticles (MSNs) were covalently coated with antioxidant molecules, namely, caffeic acid (MSN-CAF) or rutin (MSN-RUT), in order to diminish the impact of oxidative stress induced after transfection into cells, thus generating safer carriers used for either drug delivery or other applications. Two cellular models involved in the entry of NPs in the body were used for this purpose: the intestinal Caco-2 and the epidermal HaCaT cell lines. Rutin gave the best results in terms of antioxidant capacities preservation during coupling procedures, cellular toxicity alleviation, and decrease of ROS level after 24 h incubation of cells with grafted nanoparticles. These protective effects of rutin were found more pronounced in HaCaT than in Caco-2 cells, indicating some cellular specificity toward defense against oxidative stress. In order to gain more insight about the Nrf2 response, a stable transfected HaCaT cell line bearing repeats of the antioxidant response element (ARE) in front of a luciferase reporter gene was generated. In this cell line, both tBHQ and quercetin (Nrf2 agonists), but not rutin, were able to induce, in a dose-dependent fashion, the luciferase response. Interestingly, at high concentration, MSN-RUT was able to induce a strong Nrf2 protective response in HaCaT cells, accompanied by a comparable induction of HO-1 mRNA. The level of these responses was again less important in Caco-2 cells. To conclude, in keratinocyte cell line, the coupling of rutin to silica nanoparticles was beneficial in term of ROS reduction, cellular viability, and protective effects mediated through the activation of the Nrf2 antioxidant pathway.
Organosilica nanoparticles hold great promise for nanomedicine applications. These nanoparticles are synthesized from polytrialkoxysilylated precursors without any silica source. In this work we present two kinds of organosilica nanoparticles with either amine or ammonium walls constituting their structure. Both types of nanoparticles are very efficient for gemcitabine monophosphate delivery, a small hydrophilic anticancer drug whose encapsulation is still a challenge. The nanoparticles are endocytosed by MCF‐7 breast cancer cells as monitored by confocal microscopy. They are efficient and lead to 60% cancer cell death.
(1) Background: Nanomedicine has recently emerged as a new area of research, particularly to fight cancer. In this field, we were interested in the vectorization of pepstatin A, a peptide which does not cross cell membranes, but which is a potent inhibitor of cathepsin D, an aspartic protease particularly overexpressed in breast cancer. (2) Methods: We studied two kinds of nanoparticles. For pepstatin A delivery, mesoporous silica nanoparticles with large pores (LPMSNs) and hollow organosilica nanoparticles (HOSNPs) obtained through the sol–gel procedure were used. The nanoparticles were loaded with pepstatin A, and then the nanoparticles were incubated with cancer cells. (3) Results: LPMSNs were monodisperse with 100 nm diameter. HOSNPs were more polydisperse with diameters below 100 nm. Good loading capacities were obtained for both types of nanoparticles. The nanoparticles were endocytosed in cancer cells, and HOSNPs led to the best results for cancer cell killing. (4) Conclusions: Mesoporous silica-based nanoparticles with large pores or cavities are promising for nanomedicine applications with peptides.
The sol‐gel synthesis of hollow organosilica nanoparticles incorporating amino groups with uniform size are described. These nanoparticles were successfully prepared via a microemulsion method. Then, the hollow nanoparticles were loaded with gemcitabine hydrochloride or methotrexate and studied in MCF‐7 breast cancer cells.
Ni-incorporated MgFe2O4 (Mg0.5Ni0.5Fe2O4) porous nanofibers were synthesized using the sol–gel electrospinning method. The optical bandgap, magnetic parameters, and electrochemical capacitive behaviors of the prepared sample were compared with pristine electrospun MgFe2O4 and NiFe2O4 based on structural and morphological properties. XRD analysis affirmed the cubic spinel structure of samples and their crystallite size is evaluated to be less than 25 nm using the Williamson–Hall equation. FESEM images demonstrated interesting nanobelts, nanotubes, and caterpillar-like fibers for electrospun MgFe2O4, NiFe2O4, and Mg0.5Ni0.5Fe2O4, respectively. Diffuse reflectance spectroscopy revealed that Mg0.5Ni0.5Fe2O4 porous nanofibers possess the band gap (1.85 eV) between the calculated value for MgFe2O4 nanobelts and NiFe2O4 nanotubes due to alloying effects. The VSM analysis revealed that the saturation magnetization and coercivity of MgFe2O4 nanobelts were enhanced by Ni2+ incorporation. The electrochemical properties of samples coated on nickel foam (NF) were tested by CV, GCD, and EIS analysis in a 3 M KOH electrolyte. The Mg0.5Ni0.5Fe2O4@Ni electrode disclosed the highest specific capacitance of 647 F g−1 at 1 A g−1 owing to the synergistic effects of multiple valence states, exceptional porous morphology, and lowest charge transfer resistance. The Mg0.5Ni0.5Fe2O4 porous fibers showed superior capacitance retention of 91% after 3000 cycles at 10 A g−1 and notable Coulombic efficiency of 97%. Moreover, the Mg0.5Ni0.5Fe2O4//Activated carbon asymmetric supercapacitor divulged a good energy density of 83 W h Kg−1 at a power density of 700 W Kg−1.
(1) Background: Due to human activities, greenhouse gas (GHG) concentrations in the atmosphere are constantly rising, causing the greenhouse effect. Among GHGs, carbon dioxide (CO2) is responsible for about two-thirds of the total energy imbalance which is the origin of the increase in the Earth’s temperature. (2) Methods: In this field, we describe the development of periodic mesoporous organosilica nanoparticles (PMO NPs) used to capture and store CO2 present in the atmosphere. Several types of PMO NP (bis(triethoxysilyl)ethane (BTEE) as matrix, co-condensed with trialkoxysilylated aminopyridine (py) and trialkoxysilylated bipyridine (Etbipy and iPrbipy)) were synthesized by means of the sol-gel procedure, then characterized with different techniques (DLS, TEM, FTIR, BET). A systematic evaluation of CO2 adsorption was carried out at 298 K and 273 K, at low pressure. (3) Results: The best values of CO2 adsorption were obtained with 6% bipyridine: 1.045 mmol·g−1 at 298 K and 2.26 mmol·g−1 at 273 K. (4) Conclusions: The synthetized BTEE/aminopyridine or bipyridine PMO NPs showed significant results and could be promising for carbon capture and storage (CCS) application.
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