pH-sensitive release of insulin-loaded mesoporous silica particles and its coordination mechanism

Synthesis, spectroscopic, computational, molecular docking, antidiabetic(in vitro & in vivo) DNA and BSA interaction studies of ruthenium(II) carboxylate complexes

The ruthenium compounds have been known to have the wide range of potential applications as anticancer, antibacterial and anti-diabetic etc. The ligand substitutions play a vital role in enhancing the pharmacological and biological activities. In the present study, three ruthenium-metal based complexes, designated as (I-III), were synthesized and characterized employing element analysis, FTIR and 1HNMR. Density functional theory (DFT) was employed to work out FMO (frontier molecular orbital), NBO (natural bond orbital), UV-visible and FTIR analysis. The obtained results are comparable to the experimental findings. The complexes (I-III) were tested for pharmacological activities such as anti-diabetic (in vitro and in vivo). In vitro, anti-diabetic analysis of α-amylase inhibition enzyme dinitrosalicylic acid (DNSA) reagent confirmed inhibitory influence of the synthesized complexes (I-III). In vivo, investigation was conducted on rabbits as model. The bio-clinical tests such as glycated haemoglobin concentration (HbA1c), blood urea nitrogen (BUN), creatinine (Cr), blood glucose level (BGL), high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol (TC) were performed using the blood, plasma specimens isolated from diabetic, non-diabetic, control and treatment groups (n = 18). The results showed that complexes were significantly controlled the enrichment in tested parameters. The complexes (I-III) were also tested for antitumor potential using salmon sperm DNA (SSDNA), and bovine serum albumin (BSA). The results showed effective interaction for complexes (I-III) with obtained good binding constant values. The molecular docking studies were also done to compare and support the experimental results.

Mesoporous silica particles are phagocytosed by microglia and induce a mild inflammatory response in vitro

Aim: Mesoporous silica particles (MSPs) are broadly used drug delivery carriers. In this study, the authors analyzed the responses to MSPs of astrocytes and microglia, the two main cellular players in neuroinflammation. Materials & methods: Primary murine cortical mixed glial cultures were treated with rhodamine B-labeled MSPs. Results: MSPs are avidly internalized by microglial cells and remain inside the cells for at least 14 days. Despite this, MSPs do not affect glial cell viability or morphology, basal metabolic activity or oxidative stress. MSPs also do not affect mRNA levels of key proinflammatory genes; however, in combination with lipopolysaccharide, they significantly increase extracellular IL-1β levels. Conclusion: These results suggest that MSPs could be novel tools for specific drug delivery to microglial cells.

Meso-Cellular Silicate Foam-Modified Reduced Graphene Oxide with a Sandwich Structure for Enzymatic Immobilization and Bioelectrocatalysis

An integrated composite of meso-cellular silicate foam (MCF)-modified reduced graphene oxide (MCF@rGO) was designed and synthesized based on polyethylene oxide-polypropylene oxide-polyethylene oxide (P123)-modified rGO (P123-rGO). As the polymeric template for the fabrication of mesoporous silicates, modified P123 greatly improved the affinity between the nanosheet and the in situ formed MCFs, resulting in the formation of thin layers of MCFs on both sides of rGO. Therefore, the MCFs@rGO formed exhibited a unique sandwich structure with an inner skeleton of rGO and two outer layers of MCFs. The outer modification by MCFs, with the presence of large mesopores, not only shifted the surface property of rGO from hydrophobic to hydrophilic but also offered immobilized enzymes a favorable microenvironment to maintain their bioactivity. Meanwhile, the inner skeleton of rGO compensated for the weak conductivity of MCFs, providing a pathway for the direct electron transfer (DET) of various redox enzymes or proteins, such as hemoglobin (Hb), horseradish peroxidase, glucose oxidase (GOD), and cholesterol oxidase. It was found that the DET signal obtained from Hb-MCFs@rGO/glassy carbon electrode (GCE) was much larger than the sum of the signals from two components-based modified electrodes of Hb-P123-rGO/GCE and Hb-MCFs/GCE. A similar improvement in DET signal was also observed using GOD-MCFs@rGO/GCE. The significant enhancement of DET signals for both protein electrodes can be ascribed to the synergistic effects generated from the integration of the two components, one of which enhances biocompatibility and the other enhances conductivity. The bioelectrocatalytic performance of Hb and GOD electrodes was further investigated. As for Hb-MCFs@rGO/GCE, the GOD electrode displayed excellent analytical performance for the detection of hydrogen peroxide (H₂O₂), including a good sensitivity of 0.25 μA μmol^-1 L cm^-2, a low detection limit of 63.6 nmol L^-1 based on S/N = 3, and a low apparent Michaelis-Menten constant (K_M^app) of 49.05 μmol L^-1. GOD-MCFs@rGO/GCE also exhibited good analytical performance for the detection of glucose, with a wide linear range of 0.25-8.0 mmol L^-1. In addition, blood glucose detection in samples of human serum was successfully achieved using GOD-MCFs@rGO/GCE with a low quantification limit.