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The authors describe a novel water-soluble, stable, biocompatible, and highly fluorescent probe consisting of iron quantum clusters incorporated into human adult hemoglobin (Hb-FeQCs). The Hb-FeQCs were characterized by various spectroscopic techniques. The probe displays strong absorption and yellow fluorescence with a peak centered at 567 nm (photo-excited at 460 nm). The Hb-FeQCs show excellent photostability over a wide range of pH values (5-12), even in the presence of high electrolyte concentrations. A colorimetric and a fluorometric method were worked out for the quantitation Zn(II) and cysteine in aqueous solution. Zinc ions induce a visible color change from brown to yellow. The sensitivity of Hb-FeQCs towards other metal ions was negligible, with the exception of Co2+1 and Cu2+, which caused a modest interference. The Hb-FeQCs were exploited in a sensitive and selective turn-on fluorescence assay for Zn2+. It is also found that cysteine quenches the fluorescence of the Hb-FeQCs/Zn(II) complex. Under the optimized conditions, the probe has a linear response in the 0.04 to 2.2 µM Zn(II) concentration range, with a 48 nM detection limit. Response to cysteine is linear in the 1-60 µM concentration range, with a 0.25 µM limit of detection. This fluorescent probe undergoes fluorescent emission intensity enhancement upon binding to zinc ions in living normal human fibroblast cells under visible lamp. The cellular imaging capability and very low cytotoxicity of this soluble iron quantum clusters can be potentially extended as an exciting sub-nanoplatform with promising biomaterial applications. [ABSTRACT FROM AUTHOR]

A novel design of gold-coated iron oxide nanoparticles was fabricated as a potential delivery system to improve the efficiency and stability of d, l-sulforaphane as an anticancer drug. To this purpose, the surface of gold-coated iron oxide nanoparticles was modified for sulforaphane delivery via furnishing its surface with thiolated polyethylene glycol-folic acid and thiolated polyethylene glycol-FITC. The synthesized nanoparticles were characterized by different techniques such as FTIR, energy dispersive X-ray spectroscopy, UV-visible spectroscopy, scanning and transmission electron microscopy. The average diameters of the synthesized nanoparticles before and after sulforaphane loading were obtained ∼ 33 nm and ∼ 38 nm, respectively, when ∼ 2.8 mmol/g of sulforaphane was loaded. The result of cell viability assay which was confirmed by apoptosis assay on the human breast cancer cells (MCF-7 line) as a model of in vitro-cancerous cells, proved that the bare nanoparticles showed little inherent cytotoxicity, whereas the sulforaphane-loaded nanoparticles were cytotoxic. The expression rate of the anti-apoptotic genes (bcl-2 and bcl-xL), and the pro-apoptotic genes (bax and bak) were quantified, and it was found that the expression rate of bcl-2 and bcl-xL genes significantly were decreased when MCF-7 cells were incubated by sulforaphane-loaded nanoparticles. The sulforaphane-loaded into the designed gold-coated iron oxide nanoparticles, acceptably induced apoptosis in MCF-7 cells. [ABSTRACT FROM AUTHOR]

New Ag(I) complexes of N-nicotinyl, N′,N″-bis(cyclohexyl) phosphoric triamide, 3-NC 5 H 4 C(O)NHP(O)[NH(C 6 H 11 )] 2 ( L 1 ), and N-nicotinyl, N′,N″-bis(tert-butyl) phosphoric triamide, 3-NC 5 H 4 C(O)NHP(O)[NHC(CH 3 ) 3 ] 2 ( L 2 ), with formula Ag( L 1 ) 2 NO 3 ( C 1 ) and Ag( L 2 ) 2 NO 3 ( C 2 ) were synthesized and characterized by NMR, IR, UV–Vis spectroscopy and elemental analysis. Molecular structures of C 1 and C 2 were determined by X-ray crystallography and revealed that coordination of ligands to Ag(I) has been occurred from the nitrogen atom of the pyridine ring. Also, compound C 1 exists as two conformers in crystalline structure which are weakly connected to each other through intermolecular Ag…O C electrostatic interaction. Ag(I) complexes and the corresponding ligands were screened for their antibacterial activity against selected Gram-positive and Gram-negative bacteria, showing bactericidal activity for complexes. In vitro cytotoxicity of compounds was studied against human carcinoma cell lines, HeLa (cervical cancer), MCF-7 (breast cancer) and MG-63 (osteosarcoma). Results indicated that C 1 and C 2 possess strong cytotoxic activity against cancer cells with IC 50 values ranging from 3.3 to 15.3 μM for two exposure time (24 and 48 h). The cytotoxicity of complexes against non-tumorigenic breast cell, MCF-10A was further evaluated. Structure–activity relationships have been also discussed. [ABSTRACT FROM AUTHOR]

• Two Pd(II) complexes, [Pd(bipy)(mtzt) 2 ] (1) and [Pd(5,6-dmphen)(mtzt) 2 ] (2), were synthesized and fully characterized. • According to the single-crystal X-ray diffraction studies, central Pd(II) ions in 1 and 2 have a slightly distorted square-planar geometry. • The anti-tumor properties of Pd(II) complexes were evaluated as in vitro anti-proliferative activity by MTT assay in human breast cancer cell lines. • The interaction of the complexes with DNA have been performed. Complexes [Pd(bipy)(mtzt) 2 ] (1) and [Pd(5,6-dmphen)(mtzt) 2 ] (2) (where Hmtzt, bipy and 5,6-dmphen are 1-methyl-1 H -1,2,3,4-tetrazole-5-thiol, 2,2′-bipyridine and 5,6-dimethyl-1,10-phenanthroline, respectively) were synthesized by the reaction of a mixture of Hmtzt and 2,2′-bipyridine (1) or 5,6-dimethyl-1,10-phenanthroline (2) with Pd(II) chloride. Complexes 1 and 2 were fully characterized by elemental analysis, 1H NMR, IR, UV–Vis, luminescence spectroscopy as well as single-crystal X-ray diffraction method. According to single-crystal X-ray diffraction, central Pd(II) ions in 1 and 2 have a slightly distorted square-planar geometry, involving the S atoms from two mptrz− ligands and two nitrogen atoms from bipy (complex 1) and 5,6-dmphen (complex 2) ligands (τ 4 = 0.09 for 1 and 0.07 for 2). Additionally, some well-known non-covalent intermolecular interactions such as hydrogen bonding (complexes 1 and 2), π–π (complexes 1 and 2), and ring-metal interactions (complex 2) have also been involved in these complexes. These kinds of interactions have been observed to be responsible for the formation of the 3D supramolecular structure. The luminescence properties of the free ligand, as well as the complexes 1 and 2 , were investigated in solution. The interaction of the complexes with DNA was investigated by UV–Vis absorption spectra. The results indicate that complexes bind to DNA and the intrinsic binding constant (K b) of complexes 1 and 2 were about 2.19 × 105 and 1.51 × 105 M−1, respectively. Gel electrophoresis assay demonstrates the ability of the complexes to bind the plasmid DNA. The anti-tumor properties of Pd(II) complexes were evaluated as in vitro anti-proliferative activity by MTT assay in human breast cancer cell lines (MCF-7, SKBR-3, and MDA-MB-231). It suggests that complex 2 might dedicate important anti-tumor properties and 5,6-dmphen ligand has an important effect on cytotoxicity, so complex 2 shows IC 50 value in μM range as effective as cisplatin. [ABSTRACT FROM AUTHOR]

Encapsulation of ES-SS peptide in nano-sized liposome to increase stability and plasma half-life of the endostatin peptide. • A variant of endostatin, ES_SS peptide, was encapsulated in the liposome. • Liposomal peptide show better stability and plasma half-life in the bloodstream. • The ES-SS peptide embedded in the liposomal core space with slow release rate. • The MD illustrated self-assembly of peptides, helping the durability of the liposome. The endostatin protein is a potent inhibitor of angiogenesis and tumor growth. The anti-angiogenic and antitumor properties of full-length endostatin can be mimicked by its N-terminal segment, including residues 1-27. Therefore, our previous studies have shown that a mutant N-terminal peptide which the Zn-binding loop was replaced by a disulfide loop (referred to as the ES-SS peptide) has preserved antiangiogenic and antitumor properties compared to the native peptide. To increase stability and plasma half-life of the ES-SS peptide, the nano-sized liposomal formulations of the peptide with different ratio of phosphocholine (PC) were synthesized. The liposomal peptide formulations possessed an average size of around 100 nm with (−4 to −36 mv) in zeta potential. The encapsulation efficiency of the ES-SS peptide was in the range of 24–54% with different lipid: peptide molar ratios. In vitro release of the peptide from liposomes indicated a complete peptide release after 7 days. Cytotoxicity assay was evaluated using the human umbilical vein endothelial cells (HUVECs) for various concentrations of the liposomal peptide. The results depicted the gradual release of the peptide through liposomes. By comparing with the free peptide, the liposomal peptide formulations have indicated higher cell viability with IC 50 value about 0.1 μM. The peptide-liposome interactions, as well as the peptide effect on the liposome structure, were also investigated through coarse-grained molecular dynamics (CG-MD) simulation. The results revealed that the peptides were assembled in the hydrophilic core of the liposome. The peptide behavior in liposome can stabilize the liposome structure and be a response to the observed low peptide release rate. The investigation is promising for designing a liposome-based anti-angiogenesis peptide delivery system. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) represent a new generation of graphene-based nanomaterials with enormous potential for use and development of a variety of biomedical applications. However, up to now little studies have investigated the impact of GQDs on human health in case of exposure. GQDs were synthesized from citric acid as carbon precursor by hydrothermal treatment at 160 °C for 4 h. The synthesized GQDs showed strong blue emission under UV-Irradiation with fluorescence quantum yield of 9.8%. The obtained GQDs were further carbonized, activated and functionalized by nitric acid vapor method. Nitrogen adsorption/desorption isotherms were used to analyze the surface area and porous structures of GQDs. The results revealed that compared to GQDs, the specific surface area of functionalized graphene quantum dots (fGQDs) has been increased from 0.0667 to 2.5747 m2/g and pore structures have been enhanced significantly. The potential cytotoxic effect of GQDs, fGQDs and GO suspensions was evaluated on HFF cell line using MTT assays and flow cytometry method after 24 h incubation. We have for the first time demonstrated that by carbonization, activation and functionalization of GQDs they still showed cytocompatible properties. We observed excellent biocompatibility of GQDs and fGQDs at low concentrations. Moreover, the results suggested that modification of GQDs yields product suspensions with high surface area, enhanced pore volume and loading capacities. Thus, fGQDs represent an attractive candidate for further use in drug delivery systems and bio-imaging application. Novel modified graphene quantum dots prepared from natural, eco-friendly and biocompatible materials. Unlabelled Image • Blue luminescent graphene quantum dots were modified by acid vapor method. • The modified graphene quantum dots showed very high specific surface area with enhanced pore structures. • The functionalized graphene quantum dots revealed high loading capacities. • The excellent biocompatibility was confirmed toward HFF cells at low concentrations. [ABSTRACT FROM AUTHOR]