Palladium is a member of the platinum group of metals and can be used in the electronics industry for applications such as preparing precision resistors. It is also utilized for catalysis in organic chemistry to achieve faster reaction speeds and lower costs of production in industry. Overexposure to Pd is harmful to the environment and to human health because it can be conveyed quickly to the liver, kidney, spleen, adrenal glands, lungs, and bones. Herein, a fluorescent probe that contains an alkynyl group for specific reaction with Pd^II ions, and a naphthalimide group as a fluorophore was designed. This probe has high specificity and selectivity for Pd^II ions relative to many other metal ions. HPLC analysis was carried out to verify the mechanism of the detection. There is a distinct color change during the detection process. The influence of pH values shows that the probe is suitable to detect Pd^II ions in the range pH 6–9.

Cationic polysaccharides have been receiving more attentions and used as nonviral gene delivery vectors. In this paper, quaternized hydroxyethylcellulose (QHEC) derivatives were studied as gene carriers for their efficient DNA binding abilities. All QHECs could form stable QHEC/DNA complexes and resist the degradation of DNase I. And the dynamic light scatter (DLS) results showed that all QHEC/DNA complexes could form compact particles. These QHEC/DNA complexes exhibited effective transfection abilities in comparison to the naked DNA. The cytotoxicities of QHEC and QHEC/DNA complexes were also evaluated in four cell lines which were relatively low compared with 25 kDa bPEI. All results indicated that these quaternized hydroxyethylcelluloses could be used as potential gene delivery vectors.

In the presence of hemin and under appropriate conditions, some modalities of G-quadruplexes can form a peroxidase-like DNAzyme that has been widely used in biology. Structurefunction studies on the DNAzyme revealed that its catalytic ability may be dependent on the unimolecular parallel G-quadruplex. In this report, we present the preliminary investigation on the relationship between the structure and function of DNAzymes through a terminal oligo modification in G-quadruplex sequences by adding different lengths of oligo-dT to the 3′- or 5′-end of the aptamers. The results suggested that adding dT_n to the 5′-end of the DNA sequence of the enzyme improved the ability of hemin to bind with DNA, but the addition of dT_n to the 3′-end decreased the binding ability of hemin for DNA. The increased stability of the assembled DNAzyme would lead to more favorable binding between the enzyme and substrate (H₂O₂), facilitating higher peroxidase activity; on the contrary, with lower stability of the DNAzyme complex, we observed reduced peroxidase activity.

DNA damage plays an important role in cellular processes. Besides natural protein nucleases, different types of efficient agents for DNA damage have been developed over recent decades in the search for new anticancer and antiviral drugs. In addition to the double-stranded configuration, DNA structures also include some non-duplex regions, which are considered to be from spontaneous errors in DNA replication, thus playing an important role for cells. Herein, we focused on these non-duplex regions of DNA and generated manganese(III) corroles, which exhibit a highly selective cleavage ability for guanosine units located at non-duplex portions, such as loops and bulges. The cleavage mechanism was demonstrated to be a manganese-induced oxidation process. The results given herein show a molecular approach that could specifically probe the guanosine units in DNA non-duplex structures, thus representing a promising step in the construction of tools to target non-duplex structures in chromosomes.

G-quadruplex DNA plays an important role in the potential therapeutic target for the design and development of anticancer drugs. As various G-quadruplex sequences in the promoter regions or telomeres can form different secondary structural modes and display a diversity of biology functions, variant G-quadruplex interactive agents may be necessary to cure different disease by differentiating variant types of G-quadruplexes. We synthesize five cationic methylpyridylium corroles and compare the interactions of corroles with different types of G-quadruplexes such as cmyc, htelo, and bcl2 by using surface plasmon resonance. Because of the importance of human telomere G-quadruplex DNA, we focus on the biological properties of the interactions between human telomere G-quadruplex DNA and corrole isomers using CD, T_m, PCR-stop (PCR= polymerase chain reaction), and polymerase-stop assay, which demonstrate the excellent ability of the corrole to induce and stabilize the G-quadruplex. This study provides the first experimental insight into how selectivity might be achieved for different G-quadruplexes by a single group of methylpyridylium corrole isomers that may be optimized for potential selective cancer therapy.

A series of cationic ester porphyrins are much more cytotoxic to tumor cells than photofrin, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP4), and cisplatin. The lowest IC₅₀ value for SGC7901 is ca. 6 nMin vitro with irradiation. These porphyrins also exhibited the most potent photo-induced cytotoxicity without photobleaching. HeLa Cell apoptosis induced by cationic ester porphyrins after illumination was examined by flow cytometric analysis, staining assays with propidium iodide and annexin V FITC-PI, and further confirmed by observing morphological changes in the cells. The result of this study indicates that these cationic ester porphyrins may be applied in photodynamic therapy (PDT) in the future.

A series of systematically modified porphyrin esters, compounds 1–6, with multiple, permanent positive charges introduced at the meso-positions via N-methylated 4-, 3-, or 2-pyridyl moieties, were prepared and characterized. Their singlet-oxygen production, CT-DNA-binding properties, and plasmid-DNA photocleavage propensities were determined spectroscopically and by gel electrophoresis, and compared to those of the known, fourfold-charged parent porphyrin 4,4′,4″,4′′′-porphyrin-5,10,15,20-tetrayltetrakis(1-methylpyridinium) (TMPyP4). Some interesting structure–activity relationships could be established to rationalize effects affecting DNA binding mode and cleavage ability.

A series of pyridinium and quaternary ammonium copper corroles has been designed and synthesized. All new compounds have been fully characterized by NMR spectroscopy, high-resolution mass spectrometry, UV/Vis spectrscopy, and elemental analysis. Biochemical studies have indicated that all of these corrole derivatives can stabilize G-quadruplex structures, with corrole 4 being the most effective according to the results of circular dichroism (CD) melting experiments, polymerase chain reaction (PCR) stop assays, and surface plasmon resonance (SPR) experiments. Moreover, both corroles 3 and 4 tend to induce the human telomeric sequence to form hybrid G-quadruplex structures, whereas corroles 8 and 9 are more inclined to induce the human telomeric sequence to form antiparallel G-quadruplex structures.