The activity, distribution, and colocalization of cathepsin K and matrix metalloproteases in intact and eroded dentin.

OBJECTIVES: This study aimed to assess the activity, distribution, and colocalization of cathepsin K (catK) and matrix metalloproteases (MMPs) in both intact and eroded dentin in vitro. MATERIALS AND METHODS: Eroded dentin was obtained by consecutive treatment with 5% citric acid (pH = 2.3) for 7 days, while intact dentin remained untreated. Pulverized dentin powder (1.0 g) was extracted from both intact and eroded dentin using 5 mL of 50 mM Tris-HCl buffer (0.2 g/1 mL, pH = 7.4) for 60 h to measure the activity of catK and MMPs spectrofluorometrically. In addition, three 200-µm-thick dentin slices were prepared from intact and eroded dentin for double-labeling immunofluorescence to evaluate the distribution and colocalization of catK and MMPs (MMP-2 and MMP-9). The distribution and colocalization of enzymes were analyzed using inverted confocal laser scanning microscopy (CLSM), with colocalization rates quantified using Leica Application Suite Advanced Fluorescent (LAS AF) software. One-way analysis of variance (ANOVA) was used to analyze the fluorescence data related to enzyme activity (α = 0.05). RESULTS: The activity of catK and MMPs was significantly increased in eroded dentin compared with intact dentin. After erosive attacks, catK, MMP-2, and MMP-9 were prominently localized in the eroded regions. The colocalization rates of catK with MMP-2 and MMP-9 were 13- and 26-fold higher in eroded dentin, respectively, than in intact dentin. CONCLUSIONS: Erosive attacks amplified the activity of catK and MMPs in dentin while also altering their distribution patterns. Colocalization between catK and MMPs increased following erosive attacks. CLINICAL RELEVANCE: CatK, MMP-2, and MMP-9 likely play synergistic roles in the pathophysiology of dentin erosion.

Aloe derived nanovesicle as a functional carrier for indocyanine green encapsulation and phototherapy.

BACKGROUND: Cancer is one of the devastating diseases in the world. The development of nanocarrier provides a promising perspective for improving cancer therapeutic efficacy. However, the issues with potential toxicity, quantity production, and excessive costs limit their further applications in clinical practice. RESULTS: Herein, we proposed a nanocarrier obtained from aloe with stability and leak-proofness. We isolated nanovesicles from the gel and rind of aloe (gADNVs and rADNVs) with higher quality and yield by controlling the final centrifugation time within 20 min, and modulating the viscosity at 2.98 mPa S and 1.57 mPa S respectively. The gADNVs showed great structure and storage stability, antioxidant and antidetergent capacity. They could be efficiently taken up by melanoma cells, and with no toxicity in vitro or in vivo. Indocyanine green (ICG) loaded in gADNVs (ICG/gADNVs) showed great stability in both heating system and in serum, and its retention rate exceeded 90% after 30 days stored in gADNVs. ICG/gADNVs stored 30 days could still effectively damage melanoma cells and inhibit melanoma growth, outperforming free ICG and ICG liposomes. Interestingly, gADNVs showed prominent penetrability to mice skin which might be beneficial to noninvasive transdermal administration. CONCLUSIONS: Our research was designed to simplify the preparation of drug carrier, and reduce production cost, which provided an alternative for the development of economic and safe drug delivery system.

[Study on the enrichment and purification of total flavonoids in Schizonepeta tenuifolia by macroporous adsorption resin].

OBJECTIVE: To establish an optimum enrichment and purification process of total flavonoids in Schizonepeta tenuifolia by macroporous resins. METHODS: 9 kinds of resins were compared and the best one was chosen. Then the technique condition for separating and purifying total flavonoids from Schizonepeta tenuifolia was studied. RESULTS: HP-20 was selected for its excellent adsorption and desorption properties, 80% ethanol was found to be the best elution solution. The best result was based on the follows: pH value-6.0, feeding rate-2 BV/h,sample concentration-0.4 g/mL, the ratio of total flavonoids to HP-20 macroporous resin-133. 76 mg/g, elution flowing rate-4 BV/h, eluting agent amount-3 BV. Then the purity reached 74. 31% and the yield was 97.13%. CONCLUSION: The total flavonoids of Schizonepeta tenuifolia can be effectively purificated and separated by HP-20 macroporous resin.

Functionalized porous magnetic cellulose/Fe3O4 beads prepared from ionic liquid for removal of dyes from aqueous solution.

Porous magnetic cellulose/Fe3O4 beads (CFBs), consisting of cellulose as matrix and ferrosoferric oxide, were successfully fabricated from microcrystalline cellulose dissolved in an ionic liquid and further modified with glutaric anhydride. The porous structure of modified magnetic cellulose/Fe3O4 beads (MCFBs) was created by nano-sized calcium carbonate (CaCO3). The resulting MCFBs were well characterized and employed as effective adsorbents for removal of dyes from aqueous solution. The adsorption behaviors indicated that the adsorption kinetics was preferably fitted to the pseudo-second-order kinetic model; whereas the adsorption isotherms were well described by Langmuir model with the maximum adsorption capacity of 1186.8 and 151.8 mg/g for methylene blue (MB) and Rhodamine B (RhB), respectively. Moreover, MCFBs are magnetically separable, thus leading to a range of green-based and promising adsorbents towards organic pollutants with easy recovery.

Cellulose-based adsorbents loaded with zero-valent iron for removal of metal ions from contaminated water.

Sawdust loaded with zero-valent iron (S-ZVI) was prepared using a liquid phase reduction method for removing heavy metal ions from contaminated water. Surface chemistry and morphology of adsorbents were characterized with Fourier transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), SEM-mapping, EDX, and X-ray photoelectron spectrum (XPS). The results demonstrated that the zero-valent iron was successfully loaded onto the sawdust. The impact of various factors such as pH, initial metal ion concentration, temperature, and contact time on the removal capability of the adsorbents was systematically investigated. The equilibrium adsorption data showed that the adsorption of arsenic ions and Cr(III) followed the Langmuir model well, and the maximum adsorption reached 111.37 and 268.7 mg/g in an aqueous solution system. In addition, the adsorption kinetics was more accurately described by the pseudo-second-order model, suggesting the domination of chemical adsorption. Meanwhile, the results on recyclability indicated that the high performance of S-ZVI on the removal of arsenic ions was well maintained after three regeneration cycles. The adsorption mechanism revealed in this work suggested that S-ZVI improved the dispersion of ZVI by minimizing the agglomeration, thus leading to highly effective adsorption via chelation, electrostatic interaction, and redox reaction.

Adsorption of Hg (II) ions from aqueous solution by diethylenetriaminepentaacetic acid-modified cellulose.

The diethylenetriaminepentaacetic acid (DTPA)-modified cellulose adsorbent was prepared using N­[3­(trimethoxysilyl)propyl]ethylenediamine as a crosslinking reagent and used for the removal of Hg (II) ions from aqueous solution. The resulting adsorbents were comprehensively characterized with FTIR, XRD and SEM. The results showed that DTPA successfully functionalized cellulose, and coordinating DTPA ligand improved the binding properties towards heavy metal ions significantly. Various influencing factors on adsorption performance were investigated, including temperature, initial concentration of Hg (II), solution pH, contact time. Moreover, the reusability of the adsorbent was also assessed. The experimental and modeling results indicated that the adsorption process was better described by Langmuir isotherm model, and the maximum adsorption capacity reached as high as 476.2 mg·g-1, The kinetic date of the adsorption matched well with the pseudo-second-order kinetic model. Furthermore, the cellulose-based adsorbent is reusable, maintaining the adsorption capacity after seven adsorption-desorption cycles. The findings from this work demonstrated that the DTPA-modified cellulose adsorbent can be recognized as an effective adsorbent for Hg (II) removal from aqueous solution.

AC105 Increases Extracellular Magnesium Delivery and Reduces Excitotoxic Glutamate Exposure within Injured Spinal Cords in Rats.

Magnesium (Mg2+) homeostasis is impaired following spinal cord injury (SCI) and the loss of extracellular Mg2+ contributes to secondary injury by various mechanisms, including glutamate neurotoxicity. The neuroprotective effects of high dose Mg2+ supplementation have been reported in many animal models. Recent studies found that lower Mg2+ doses also improved neurologic outcomes when Mg2+ was formulated with polyethylene glycol (PEG), suggesting that a PEG/ Mg2+ formulation might increase Mg2+ delivery to the injured spinal cord, compared with that of MgSO4 alone. Here, we assessed spinal extracellular Mg2+ and glutamate levels following SCI in rats using microdialysis. Basal levels of extracellular Mg2+ (∼0.5 mM) were significantly reduced to 0.15 mM in the core and 0.12 mM in the rostral peri-lesion area after SCI. A single intravenous infusion of saline or of MgSO4 at 192 µmoL/kg did not significantly change extracellular Mg2+ concentrations. However, a single infusion of AC105 (a MgCl2 in PEG) at an equimolar Mg2+ dose significantly increased the Mg2+ concentration to 0.3 mM (core area) and 0.25 mM (rostral peri-lesion area). Moreover, multiple AC105 treatments completely restored the depleted extracellular Mg2+ concentrations after SCI to levels in the uninjured spinal cord. Repeated MgSO4 infusions slightly increased the Mg2+ concentrations while saline infusion had no effect. In addition, AC105 treatment significantly reduced extracellular glutamate levels in the lesion center after SCI. These results indicate that intravenous infusion of PEG-formulated Mg2+ normalized the Mg2+ homeostasis following SCI and reduced potentially neurotoxic glutamate levels, consistent with a neuroprotective mechanism of blocking excitotoxicity.

Bacterial-cellulose-derived carbon nanofiber@MnO2 and nitrogen-doped carbon nanofiber electrode materials: an asymmetric supercapacitor with high energy and power density.

A new kind of high-performance asymmetric supercapacitor is designed with pyrolyzed bacterial cellulose (p-BC)-coated MnO2 as a positive electrode material and nitrogen-doped p-BC as a negative electrode material via an easy, efficient, large-scale, and green fabrication approach. The optimal asymmetric device possesses an excellent supercapacitive behavior with quite high energy and power density.