Rhodamine B

Rhodamine B is a staining fluorescent dye, commonly used for dyeing textiles, paper, soap, leather, and drugs.

In Vitro:Rhodamine B induces a concentration-dependent reduction of root meristem cells of A. cepa. mitotic activity. Rhodamine B induces various nuclear aberrations in A. cepa. root cells. In the 100 and 200 ppm rhodamine B groups, the frequencies of NBUDs and BN surpass those of the positive control (MMS) group. Rhodamine B-induced changes of H2O2 (a) and MDA (b) level increase in a concentration-dependent manner in A. cepa. roots[1].

References:
[1]. Tan D, et al. Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells. Environ Sci Pollut Res Int. 2014 Mar;21(5):3363-70.

Coating Titania Nanoparticles with Epoxy-Containing Catechol Polymers via Cu(0)-Living Radical Polymerization as Intelligent Enzyme Carriers.[Pubmed:29738234]

Biomacromolecules. 2018 Jul 9;19(7):2979-2990.

Immobilization of enzyme could offer the biocatalyst with increased stability and important recoverability, which plays a vital role in the enzyme's industrial applications. In this study, we present a new strategy to build an intelligent enzyme carrier by coating titania nanoparticles with thermoresponsive epoxy-functionalized polymers. Zero-valent copper-mediated living radical polymerization (Cu(0)-LRP) was utilized herein to copolymerize N-isopropylacrylamide (NIPAM) and glycidyl acrylate (GA) directly from an unprotected dopamine-functionalized initiator to obtain an epoxy-containing polymer with terminal anchor for the "grafting to" or "one-pot" modification of titania nanoparticles. A Rhodamine B-labeled laccase has been subsequently used as a model enzyme for successful immobilization to yield an intelligent titania/laccase hybrid bifunctional catalyst. The immobilized laccase has shown excellent thermal stability under ambient or even relatively high temperature above the lower critical solution temperature (LCST) at which temperature the hybrid particles could be facilely recovered for reuse. The enzyme activity could be maintained during the repeated use after recovery and enzymatic degradation of bisphenol A was proven to be efficient. The photocatalytic ability of titania was also investigated by fast degradation of Rhodamine B under the excitation of simulated sunlight. Therefore, this study has provided a facile strategy for the immobilization of metal oxide catalysts with enzymes, which constructs a novel bifunctional catalyst that will be promising for the "one-pot" degradation of different organic pollutants.

Enhanced Homing Technique of Mesenchymal Stem Cells Using Iron Oxide Nanoparticles by Magnetic Attraction in Olfactory-Injured Mouse Models.[Pubmed:29734748]

Int J Mol Sci. 2018 May 5;19(5). pii: ijms19051376.

Intranasal delivery of mesenchymal stem cells (MSCs) to the olfactory bulb is a promising approach for treating olfactory injury. Additionally, using the homing phenomenon of MSCs may be clinically applicable for developing therapeutic cell carriers. Herein, using superparamagnetic iron oxide nanoparticles (SPIONs) and a permanent magnet, we demonstrated an enhanced homing effect in an olfactory model. Superparamagnetic iron oxide nanoparticles with Rhodamine B (IRBs) had a diameter of 5.22 ± 0.9 nm and ζ-potential of +15.2 ± 0.3 mV. IRB concentration of 15 µg/mL was injected with SPIONs into MSCs, as cell viability significantly decreased when 20 μg/mL was used (p ≤ 0.005) compared to in controls. The cells exhibited magnetic attraction in vitro. SPIONs also stimulated CXCR4 (C-X-C chemokine receptor type 4) expression and CXCR4-SDF-1 (Stromal cell-derived factor 1) signaling in MSCs. After injecting magnetized MSCs, these cells were detected in the damaged olfactory bulb one week after injury on one side, and there was a significant increase compared to when non-magnetized MSCs were injected. Our results suggest that SPIONs-labeled MSCs migrated to injured olfactory tissue through guidance with a permanent magnet, resulting in better homing effects of MSCs in vivo, and that iron oxide nanoparticles can be used for internalization, various biological applications, and regenerative studies.

Protein carbonyl determination by a rhodamine B hydrazide-based fluorometric assay.[Pubmed:29727801]

Redox Biol. 2018 Jul;17:236-245.

A new fluorometric assay is presented for the ultrasensitive quantification of total protein carbonyls, and is based on their specific reaction with Rhodamine B hydrazide (RBH), and the production of a protein carbonyl-RBH hydrazone the fluorescence of which (at ex/em 560/585nm) is greatly enhanced by guanidine-HCl. Compared to the fluorescein-5-thiosemicarbazide (FTC)-based fluorometric assay, the RBH assay uses a 24-fold shorter reaction incubation time (1h) and at least 1000-fold lower protein quantity (2.5microg), and produces very reliable data that were verified by extensive standardization experiments. The protein carbonyl group detection sensitivity limit of the RBH assay, based on its standard curve, can be as low as 0.4 pmol, and even lower. Counting the very low protein limit of the RBH assay, its cumulative and functional sensitivity is 8500- and 800-fold higher than the corresponding ones for the FTC assay. Neither heme proteins hemoglobin and cytochrome c nor DNA interfere with the RBH assay.

Visible-light-driven activity and synergistic mechanism of TiO2@g-C3N4 heterostructured photocatalysts fabricated through a facile and green procedure for various toxic pollutants removal.[Pubmed:29737308]

Nanotechnology. 2018 Aug 3;29(31):315601.

Heterostructured photocatalysts based on g-C3N4 and TiO2 represent a promising kind of photocatalyst in environmental fields, but the synthesis methods are always complex and not green. In the present paper, a facile and green one-step calcination procedure at lower temperature (450 degrees C) with the assistance of water is developed to synthesize a visible-light-active TiO2@g-C3N4 heterostructured photocatalyst, which shows higher visible-light-driven activity (k = 0.014 min(-1)) than pure g-C3N4 (k = 0.0036 min(-1)) and TiO2 (k = 0.0067 min(-1)) for methyl orange degradation. Excellent performance (over 90% conversion) was also observed for the removal of Rhodamine B, phenol, and Cr(VI) under visible light. The heterostructured photocatalyst showed favorable reusability, preserving 86% of its activity after five successive cycles. A mechanism study demonstrates that the enhanced photocatalytic activity results from the efficient separation of the photo-generated charge carriers through the intimate interface between the two semiconductors based on their appropriate band structures and light-induced mechanism. The heterostructured photocatalyst will certainly find wide applications in the treatment of various toxic pollutants in wastewater using abundant solar energy. Furthermore, this facile and green procedure and the proposed synergistic mechanism will provide guidelines in designing other g-C3N4 based organic-inorganic composite photocatalysts for various applications.

Luminescence-Tunable Polynorbornenes for Simultaneous Multicolor Imaging in Subcellular Organelles.[Pubmed:29742341]

Biomacromolecules. 2018 Jul 9;19(7):2750-2758.

Through modular ROMP (ring-opening metathesis polymerization), biofunctional polynorbornenes are designed and fabricated from panchromatic fluorophores, bioactive peptides, and polyethylene glycol solubilizer for organelle-specific multicolor imaging. Attributed to the free permutation and combination of highly fluorescent red Rhodamine B, green dichlorofluorescein and blue 9,10-diphenylanthracene fluorophores as well as signaling peptide sequences of F xrF xK and TAT, we successfully realize simultaneous multicolor imaging toward lysosomes and mitochondria in living cells first utilizing polymeric scaffolds. If more biofunctions could be incorporated, modularly designed copolymer would provide a promising opportunity to facilitate multitasking application to monitoring intracellular alterations and elucidating complex biological processes.

Phospholipid-Tailored Titanium Carbide Nanosheets as a Novel Fluorescent Nanoprobe for Activity Assay and Imaging of Phospholipase D.[Pubmed:29737155]

Anal Chem. 2018 Jun 5;90(11):6742-6748.

As one of the emerging inorganic graphene analogues, two-dimensional titanium carbide (Ti3C2) nanosheets have attracted extensive attention in recent years because of their remarkable structural and electronic properties. Herein, a sensitive and selective nanoprobe to fluorescently probe phospholipase D activity was developed on the basis of an ultrathin Ti3C2 nanosheets-mediated fluorescence quenching effect. Ultrathin Ti3C2 nanosheets with approximately 1.3 nm in thickness were synthesized from bulk Ti3AlC2 powder by a two-step exfoliation procedure and further modified by a natural phospholipid that is doped with Rhodamine B-labeled phospholipid (RhB-PL-Ti3C2). The close proximity between RhB and Ti3C2 leads to efficient fluorescence quenching (>95%) of RhB by energy transfer. Phospholipase D-catalyzed lipolysis of the phosphodiester bond in RhB-PL results in RhB moving away from the surface of Ti3C2 nanosheets and subsequent fluorescence recovery of RhB, providing a fluorescent "switch-on" assay for the phospholipase D activity. The proposed nanoprobe was successfully applied to quantitatively determine phospholipase D activity with a low limit of detection (0.10 U L(-1)) and to measure its inhibition. Moreover, in situ monitoring and imaging the activity of phospholipase D in living cells were achieved using this biocompatible nanoprobe. These results reveal that Ti3C2 nanosheets-based probes exhibit great potential in fluorometric assay and clinical diagnostic applications.

Development of transethosomes formulation for dermal fisetin delivery: Box-Behnken design, optimization, in vitro skin penetration, vesicles-skin interaction and dermatokinetic studies.[Pubmed:29730964]

Artif Cells Nanomed Biotechnol. 2018;46(sup2):755-765.

The present study was conducted for the optimization of transethosomes formulation for dermal fisetin delivery. The optimization of the formulation was carried out using "Box-Behnken design". The independent variables were Lipoid S 100, ethanol and sodium cholate. The prepared formulations were characterized for vesicle size, entrapment efficiency and in vitro skin penetration study. The vesicles-skin interaction, confocal laser scanning microscopy and dermatokinetic studies were performed with optimized formulation. Results of the present study demonstrated that the optimized formulation presented vesicle size of 74.21 +/- 2.65 nm, zeta potential of -11.0 mV, entrapment efficiency of 68.31 +/- 1.48% and flux of 4.13 +/- 0.17 microg/cm(2)/h. The TEM image of optimized formulation exhibited sealed and spherical shape vesicles. Results of thermoanalytical techniques demonstrated that the prepared transethosomes vesicles formulation had fluidized the rigid membrane of rat's skin for smoother penetration of fisetin transethosomes. The confocal study results presented well distribution and penetration of Rhodamine B loaded transethosomes vesicles formulation up to deeper layers of the rat's skin as compared to the Rhodamine B-hydro alcoholic solution. Present study data revealed that the developed transethosomes vesicles formulation was found to be a potentially useful drug carrier for fisetin dermal delivery.