Evaluation of nanoparticle drug-delivery systems used in preclinical studies.

Multifunctional nanoparticles have been identified as a promising drug-delivery system for sustainable drug release. The structural and size tunability and disease-targeting ability of nanoparticles have made them more suitable for multiple drug loading and delivery, thereby enhancing therapeutic results through synergistic effects. Nanoparticulate carriers with specific features such as target specificity and stimuli-responsiveness enable selective drug delivery with lower potential side effects.

Z-form DNA specific binding geometry of Zn(II) meso-tetrakis(N-methylpyridinium-4-yl)porphyrin probed by linear dichroism spectroscopy.

Zn(II) meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (ZnTMPyP) produced a unique linear dichroism (LD) spectrum when forming a complex with Z-form poly[d(G-C)(2)]. The spectrum was characterized by a large positive wavelength-dependent LD signal in the Soret absorption region. The magnitudes of LD in both the DNA and Soret band increased as the [porphyrin]/[DNA base] ratio increased and were larger by 20-40 times compared to the negative LD of the ZnTMPyP bound to B-form poly[d(G-C)(2)] and poly[d(A-T)(2)].

The relationship between the structures of periphery ligands and the DNA binding mode of [Ru(II)(1,10-phenanthroline)(L1L2)dipyrido[3,2-a:2',3'-c]phenazine](n+) (L1=Cl or pyridine and L2=pyridine, n=1,2).

The binding modes of the [Ru(II)(1,10-phenanthroline)(L(1)L(2)) dipyrido[3,2-a:2',3'-c]phenazine](2+) {[Ru(phen)(py) Cl dppz](+) (L(1)=Cl, L(2)=pyridine) and ([Ru(phen)(py)(2)dppz](2+) (L(1)=L(2)=pyridine)} to native DNA is compared to that of the [Ru(II)(1,10-phenanthroline)(2)dipyrido[3,2-a:2',3'-c]phenazine](2+) complex ([Ru(phen)(2)dppz](2+)) by various spectroscopic and hydrodynamic methods including electric absorption, linear dichroism (LD), fluorescence spectroscopy, and viscometric titration. All measured properties, including red-shift and hypochromism in the dppz absorption band, nearly perpendicular molecular plane of the dppz ligand with respect to the local DNA helix axis, prohibition of the ethidium binding, the light switch effect and binding stoichiometry, increase in the viscosity upon binding to DNA, increase in the melting temperature are in agreement with classical intercalation of dppz ligand of the [Ru(phen)(2)dppz](2+) complex, in which both phenanthroline ligand anchored to the DNA phosphate groups by electrostatic interaction. [Ru(phen)(py)(2) dppz](2+) and [Ru(phen)(py) Cl dppz](+) complexes had one of the phenanthroline ligand replaced by either two pyridine ligands or one pyridine plus a chlorine ion.

Enantioselective binding of S- and R-ofloxacin to various synthetic polynucleotides.

The binding properties of S- and R-ofloxacin to poly[d(A-T)(2)], poly[d(G-C)(2)] and poly[d(I-C)(2)] were studied by circular dichroism (CD) and various fluorescence techniques. The spectral properties of R-ofloxacin did not change when it was mixed with poly[d(A-T)(2)] and poly[d(I-C)(2)], indicating that R-enantiomer does not interact with these polynucleotides. On the other hand, when S-ofloxacin was mixed with any polynucleotide, or R-enantiomer with poly[d(G-C)(2)], characteristic changes in CD and fluorescence were observed.