Investigation of the surface interactions of selected amides with mesoporous silica using FTIR spectroscopy and hyperspectral imaging

Stimuli-responsive core-shell-shell nanocarriers for implant-directed magnetic drug targeting

The treatment of implant-associated infections is still a major topic in medical-related research. As an evolution of classical systemic therapy, many approaches target local treatment at the infection site. Here, we present an innovative material approach to overcome the challenges of this local drug delivery. As an effective nanocarrier, we chose nanoporous silica, which fulfills the need for a high capacity to load antibacterial drugs. Combined with a magnetic iron oxide core, these core-shell particles provide a sophisticated drug-delivery system that allows targeted drug delivery to the desired tissue via a magnetic field. However, the release profile often reveals the problem of an uncontrolled burst release of the incorporated drug in physiological media, leading to the loss of the cargo en route to the site of infection and resulting in an ineffective treatment of implant-associated infection. A pH-responsive polymer shell can provide an elegant solution, as the acidic pH occurring during an infection (pH 5-6) can trigger the release precisely, preventing an early release of the drug. In this study, we selected poly(2-(diethylamino)ethyl methacrylate) (PDEMA) with a perfect fitting isoelectric point of 6.7 for the establishment of a pH-responsive polymer shell. Furthermore, we addressed the issue of a poorly stable dispersion of particles functionalized with hydrophobic polymers in physiological media by adding a sulfonic acid modification to the inner pore surface of the nanoparticles. This modification influenced the amount of attached polymer and the drug release profiles. It was also useful to increase the incorporated amount of enrofloxacin. In summary, we present innovative and effective core-shell-shell nanocarriers based on magnetic nanoporous silica nanoparticles functionalized with a pH-responsive polymer for the pH-triggered delivery of the antibiotic enrofloxacin and suitable for targeting using a magnetic field.

Mesoporous Silica Administration as a New Strategy in the Management of Warfarin Toxicity: An In-Vitro and In-Vivo Study

Purpose

Warfarin is one of the most widely used anticoagulants that functions by inhibiting vitamin K epoxide reductase. Warfarin overdose, whether intentional or unintentional, can cause life-threatening bleeding. Here, we present a novel warfarin adsorbent based on mesoporous silica that could serve as an antidote to warfarin toxicity.

Methods

Amino-functionalized mesoporous silica (MS-NH2) was synthesized based on the co-condensation method through a soft template technique followed by template removal. The prepared structure and functional group were studied by Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) checked the morphology. The capacity of MS-NH2 in the adsorption of warfarin was evaluated in vitro, at pH=7.4 and pH=1.2. In vivo evaluations were performed in control and warfarin-overdosed animal models. Overdosed animals were treated with MS-NH2 by oral gavage. Biomarkers of organ injury were assessed in animal serum.

Results

The MS-NH2 was relatively uniform, spherical with defined diameters (400 nm) and porous structure. Synthesized particles had a large surface area (1015 m2 g-1) and mean pore diameter of 2.4 nm which led to considerable adsorption capacity for warfarin 1666 mg/g. In vivo studies revealed that oral administration of MS-NH2 in mice poisoned with warfarin caused a significant difference (P<0.05) in the International Normalized Ratio (INR) and prothrombin time (PT). Moreover, the warfarin with MS-NH2 group demonstrated a notable decrease in biomarkers associated with tissue damage, such as bilirubin, lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and aspartate aminotransferase (AST).

Conclusion

The results confirm that MS-NH2 administration can be an effective treatment for warfarin toxicity and could potentially mitigate the adverse effects of warfarin poisoning.

Enhanced removal of Cr(VI) by polyethyleneimine-modified bamboo hydrochar

Hydrochar is an environmentally friendly and cheap adsorbent, but its adsorption amounts for anions is very limited. The functionalized hydrochar can overcome this shortcoming. Herein, polyethyleneimine-modified hydrochar (PEI-HC) was synthesized from hydrothermal carbonization (HTC) of methyl acrylate and bamboo after addition of initiator ammonium persulfate, and then modified by polyethyleneimine (PEI), which was used to treat Cr(VI). PEI-HC was tested by XANES, EXAFS, SEM-EDS, XPS, FTIR, N2 sorption isotherms, zeta potential, and elemental analyses. The characterizations showed that PEI was successfully grafted onto hydrochar, and the PEI-HC was rich in N and O functional groups, which presented high Cr(VI) sorption ability (528.41 mg·g-1 at pH 2). The bath experiments found the pseudo-second-order kinetic and Freundlich equations can well describe the adsorption kinetics and isotherm of the Cr(VI) adsorption onto PEI-HC, respectively. Electrostatic interaction, reduction, complexation, and H-bonding are the main removal mechanisms as supported by XANES, EXAFS, XPS, and FTIR. This study provides a strategy of combining HTC and free radical graft polymerization to convert agricultural and forestry wastes into functionalized hydrochar, showing highly efficient removal of Cr(VI).

Efficient discovery of potent α-glucosidase inhibitors from Paeoniae lactiflora using enzyme-MOF nanocomposites and competitive indicators

A great deal of attention has been paid to the seeds of Paeoniae lactiflora pall., an underutilized food resource, since its extract exhibits excellent α-glucosidase (GAA) inhibitory activity. In the present study, to gain further insight into this plant and find out potent GAA inhibitors, we established a novel ligand fishing strategy by introducing a competitive inhibitor as an indicator. After the successful establishment of this approach was verified by a series of methods, including kinetic assay, fluorescence determination, and HPLC, the newly developed ligand fishing method was applied to acquire potent GAA inhibitors from P. lactiflora seeds. Nine bioactive compounds were captured, and seven of them were identified as suffruticosol A, suffruticosol B, resveratrol, vitisin E, luteolin, trans-δ-viniferin, and ampelopsin E. The data of their GAA inhibitory activity demonstrated that these constituents were vigorously active against GAA with IC₅₀ values of 1.67-30.47 μM, while such value of 1-DNJ was 228.77 μM. Among them, vitisin E and ampelopsin E were reported to show such inhibitory activity for the first time. Collectively, our findings provide valuable clues for the further utilization of P. lactiflora seeds as a functional food, and offer a new avenue for acquiring potent inhibitors from natural resources.