Transport of Methyl <i>tert</i>-Butyl Ether through Alfalfa Plants

Concentrations measured in alfalfa plant stem segments indicated that plants grown in methyl tert-butyl ether (MTBE)-contaminated soil took up the chemical through their roots. Assuming a cylindrical shape for the plant stem, a mathematical model was developed to describe the transport of MTBE through the stems. Simulation results from uniform and nonuniform initial concentration distributions across the stem radius were compared with steady-state experimental data. With known values of plant stem radius, water usage, water content, and the distance over which the concentration decreased by 50%, the diffusion coefficient of MTBE radial transport across the plant stem was estimated with 95% confidence to be in the range of 8.43−16.2 × 10-8 cm2/s with a mean of 1.23 × 10-7 cm2/s. When the diffusion coefficient was calculated based on transient experimental data, the values with 95% confidence interval ranged from 4.14 × 10-7 to 8.00 × 10-7 cm2/s with a mean value of 6.07 × 10-7 cm2/s. The difference between these two results can be reduced by more accurate estimation of the water flow velocity through plant stems. The model is applicable to other species including sunflowers and poplars upon substitution of appropriate parameters

Supporting_information_2 – Supplemental material for Novel photosensitizing properties of porphyrin–chrysin derivatives with antitumor activity in vitro

Supplemental material, Supporting_information_2 for Novel photosensitizing properties of porphyrin–chrysin derivatives with antitumor activity in vitro by Ding Liu, Qizhi Zhang, Lang Zhang, Wenmei Yu, Huizhi Long, Jun He and Yunmei Liu in Journal of Chemical Research</p

Synthesis and biological evaluation of amino acid derivatives containing chrysin that induce apoptosis

A series of chrysin amino acid derivatives were synthesized to evaluate for their antiproliferative activities against several cancer cell lines. Among the compounds tested, N-(2-((5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yl)oxy)octanoyl)-L-leucine methyl ester(5d) presented a good anti-proliferative activity in MDA-MB-231 and MCF-7 cells. Flow cytometry analysis showed that 5d induced apoptosis and prolonged cell cycle progression in MDA-MB-231 and MCF-7 cells. Western blot analysis showed that 5d significantly inhibited Akt phosphorylation (Ser473) in MDA-MB-231 and MCF-7 cells. In addition, 5d treatment markedly downregulated Bcl-2 and upregulated Bax in a dose-dependent manner. In vitro caspase activation assay showed that 5d induced apoptosis of MDA-MB-231 cells by enhancing caspase 3/7 activity. The regulatory effect of 5d on apoptosis of MDA-MB-231 and MCF-7 cells may be induced by mitochondrial apoptosis pathway. This study is of great significance for designing and developing more effective chrysin amino acid derivatives.</p

Research on the Tooth-shaped Nanoscale Refractive Index Sensor Structure in Optical Fano Resonance

In this paper, the tooth-shaped nanoscale refractive index sensor structure is designed, which consists of a metal-insulator-metal (MIM) waveguide and an inner and outer tooth-shaped ring cavity with an embedded single ellipse (IOTRC-ESEE). The performance and structure of the overall nanoscale sensor are comprehensively evaluated by employing the finite element method (FEM) and coupled mode theory (CMT). The impact of various geometric parameters on sensor characteristics was rigorously assessed. The investigation ascertained that the thickness of the dielectric layer significantly influences the optical Fano resonance, emerging as a crucial parameter in its effectuation. The study finally shows that IOTRC-ESEE has a sensitivity of 3060 nm/RIU, a Figure of Merit (FOM) of 60, and possesses high sensitivity and structural complexity

Gold-Speckled Multimodal Nanoparticles for Noninvasive Bioimaging

In this report the synthesis, characterization, and functional evaluation of a multimodal nanoparticulate contrast agent for noninvasive imaging through both magnetic resonance imaging (MRI) and photoacoustic tomography (PAT) is presented. The nanoparticles described herein enable high resolution and highly sensitive three-dimensional diagnostic imaging through the synergistic coupling of MRI and PAT capabilities. Gadolinium (Gd)-doped gold-speckled silica (GSS) nanoparticles, ranging from 50 to 200 nm, have been prepared in a simple one-pot synthesis using nonionic microemulsions. The photoacoustic signal is generated from a nonuniform, discontinuous gold nanodomains speckled across the silica surface, whereas the MR contrast is provided through Gd incorporated in the silica matrix. The presence of a discontinuous speckled surface, as opposed to a continuous gold shell, allows sufficient bulk water exchange with the Gd ions to generate a strong MR contrast. The dual imaging capabilities of the particles have been demonstrated through <i>in silicio</i> and <i>in vitro</i> methods. The described particles also have the capacity for therapeutic applications including the thermal ablation of tumors through the absorption of irradiated light

Dual Enzyme Cascade-Activated Popcorn-Like Nanoparticles Efficiently Remodeled Stellate Cells to Alleviate Pancreatic Desmoplasia

In pancreatic cancer, excessive desmoplastic stroma severely impedes drug access to tumor cells. By reverting activated pancreatic stellate cells (PSCs) to quiescence, all-trans retinoic acid (ATRA) can attenuate their stromal synthesis and remodel the tumor-promoting microenvironment. However, its modulatory effects have been greatly weakened due to its limited delivery to PSCs. Therefore, we constructed a tripeptide RFC-modified gelatin/oleic acid nanoparticle (RNP@ATRA), which delivered ATRA in an enzyme-triggered popcorn-like manner and effectively resolved the delivery challenges. Specifically, surface RFC was cleaved by aminopeptidase N (APN) on the tumor endothelium to liberate l-arginine, generating nitric oxide (NO) for tumor-specific vasodilation. Then, massive nanoparticles were pushed from the vessels into tumors, showing 5.1- and 4.0-fold higher intratumoral accumulation than free ATRA and APN-inert nanoparticles, respectively. Subsequently, in the interstitium, matrix metalloproteinase-2-induced gelatin degradation caused RNP@ATRA to rapidly release ATRA, promoting its interstitial penetration and PSC delivery. Thus, activated PSCs were efficiently reverted to quiescence, and stroma secretion and vascular compression were reduced, thereby enhancing intratumoral delivery of small-molecule or nanosized chemotherapeutics. Ultimately, RNP@ATRA combined with chemotherapeutics markedly suppressed tumor growth and metastasis without causing additional toxicities. Overall, this work provides a potential nanoplatform for the efficient delivery of PSC-modifying agents in pancreatic cancer and other stroma-rich tumors

Cholinergic Neuron Targeting Nanosystem Delivering Hybrid Peptide for Combinatorial Mitochondrial Therapy in Alzheimer’s Disease

Mitochondrial dysfunction in neurons has recently become a promising therapeutic target for Alzheimer’s disease (AD). Regulation of dysfunctional mitochondria through multiple pathways rather than antioxidation monotherapy indicates synergistic therapeutic effects. Therefore, we developed a multifunctional hybrid peptide HNSS composed of antioxidant peptide SS31 and neuroprotective peptide S14G-Humanin. However, suitable peptide delivery systems with excellent loading capacity and effective at-site delivery are still absent. Herein, the nanoparticles made of citraconylation-modified poly­(ethylene glycol)-poly­(trimethylene carbonate) polymer (PEG-PTMC­(Cit)) exhibited desirable loading of HNSS peptide through electrostatic interactions. Meanwhile, based on fibroblast growth factor receptor 1­(FGFR1) overexpression in both the blood–brain barrier and cholinergic neuron, an FGFR1 ligand-FGL peptide was modified on the nanosystem (FGL-NP­(Cit)/HNSS) to achieve 4.8-fold enhanced accumulation in brain with preferred distribution into cholinergic neurons in the diseased region. The acid-sensitive property of the nanosystem facilitated lysosomal escape and intracellular drug release by charge switching, resulting in HNSS enrichment in mitochondria through directing of the SS31 part. FGL-NP­(Cit)/HNSS effectively rescued mitochondria dysfunction via the PGC-1α and STAT3 pathways, inhibited Aβ deposition and tau hyperphosphorylation, and ameliorated memory defects and cholinergic neuronal damage in 3xTg-AD mice. The work provides a potential platform for targeted cationic peptide delivery, harboring utility for peptide therapy in other neurodegenerative diseases