1. A novel approach to the high-specific-activity labeling of small peptides with the technetium-99m fragment [99mTc(N)(PXP)]2+ (PXP = diphosphine ligand)
F Tisato, L Uccelli, F Refosco, C Bolzati, E Malagò, A Boschi, E Benini, A Duatti, A Piffanelli Bioconjug Chem . 2001 Nov-Dec;12(6):1035-42. doi: 10.1021/bc0155162.
A new labeling approach for incorporating bioactive peptides into a technetium-99m coordination complex is described. This method exploits the chemical properties of the novel metal-nitrido fragment [99mTc(N)(PXP)]2+, composed of a terminal Tc[triple bond] N multiple bond bound to an ancillary diphosphine ligand (PXP). It will be shown that this basic, molecular building block easily forms in solution as the dichloride derivative [99mTc(N)(PXP)Cl2], and that this latter complex selectively reacts with monoanionic and dianionic, bidentate ligands (YZ) having soft, pi-donor coordinating atoms to afford asymmetrical nitrido heterocomplexes of the type [99mTc(N)(PXP)(YZ)]0/+ without removal of the basic motif [99mTc(N)(PXP)]2+. The reactions of the amino acid cysteine was studied in detail. It was found that cysteine readily coordinates to the metal fragment [99mTc(N)(PXP)]2+ either through the [NH2, S-] pair of donor atoms or, alternatively, through the [O-, S-] pair, to yield the corresponding asymmetrical complexes in very high specific activity. Thus, these results were conveniently employed to devise a new, efficient procedure for labeling short peptide sequences having a terminal cysteine group available for coordination to the [99mTc(N)(PXP)]2+ fragment. Examples of the application of this novel approach to the labeling of the short peptide ligand H-Arg-Gly-Asp-Cys-OH (H(2)1) and of the peptidomimetic derivative H-Cys-Val-2-Nal-Met-OH (H2) will be discussed.
2. Molding a silver nanoparticle template on polydimethylsiloxane to efficiently capture mammalian cells
Hong-Lei Gou, Jing-Juan Xu, Hong-Yuan Chen, Hai-Jing Bai Langmuir . 2010 Feb 16;26(4):2924-9. doi: 10.1021/la902683x.
Herein, a functional template made up of in situ synthesized silver nanoparticles (AgNPs) is prepared on polydimethylsiloxane (PDMS) for the spatial control of cell capture, where the residual Si-H groups in the PDMS matrix are used as reductants to reduce AgNO(3) for forming AgNPs. In virtue of microfluidic system, a one-dimensional array pattern of AgNPs is obtained easily. Further combining with plasma treatment, a two-dimensional array pattern of AgNPs could be achieved. The obtained PDMS-AgNPs composite is characterized in detail. The PDMS-AgNPs composite shows good antibacterial property in E. coli adhesion tests. The patterns possess hifi and high resolution (ca. 8 microm). Cell patterns with high efficiency and spatial selectivity are further formed with the aid of H-Arg-Gly-Asp-Cys-OH (RGDC) tetrapeptide which is grafted on the AgNPs template. Cells immobilized on the template show a good ability for adhesion, spreading, migration, and growth.
