A class of Ag(I) N-heterocyclic carbene silver complexes, 1–3, derived from 4,5-dichloro-1H-imidazole has been evaluated for their anticancer activity against the human cancer cell lines OVCAR-3 (ovarian), MB157 (breast), and Hela (cervical). Silver complexes 1–3 are active against the ovarian and breast cancer cell lines. A preliminary in vivo study shows 1 to be active against ovarian cancer in mice. The results obtained in these studies warrant further investigation of these compounds in vivo.

The pressing need to treat multi-drug resistant bacteria in the chronically infected lungs of cystic fibrosis (CF) patients has given rise to novel nebulized antimicrobials. We have synthesized a silver–carbene complex (SCC10) active against a variety of bacterial strains associated with CF and chronic lung infections. Our studies have demonstrated that SCC10-loaded into l-tyrosine polyphosphate nanoparticles (LTP NPs) exhibits excellent antimicrobial activity in vitro and in vivo against the CF relevant bacteria Pseudomonas aeruginosa. Encapsulation of SCC10 in LTP NPs provides sustained release of the antimicrobial over the course of several days translating into efficacious results in vivo with only two administered doses over a 72 h period.

The four SCCs described here, including their development as NP therapies, show great promise for treating a wide variety of bacterial and fungal pathogens that are not easily killed by routine antimicrobial agents.

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Although the potential benefits of gene therapy for the treatment of acquired and inherited genetic diseases have been demonstrated through preclinical studies, the results of human gene therapy trials have been disappointing. Recombinant viruses are the primary vectors of choice because of their ability to protect genetic materials, cross cellular membranes, escape from endosomes and transport their genetic materials into the nucleus. Unfortunately, viral vectors have been unable to gain widespread clinical application because of their toxicity and immunogenicity. Consequently, the need for safer alternatives has led to the development of liposomes, cationic polyplexes, microparticles and nanoparticles. Although these alternative vectors have shown promise, degradable nanoparticles are the only non-viral vectors that can provide a targeted intracellular delivery with controlled release properties. Furthermore, the potential advantage of degradable nanoparticles over their non-degradable counterparts is the reduced toxicity and the avoidance of accumulation within the target tissue after repeated administration. In this article, current non-viral gene delivery devices are reviewed with a special emphasis on nanoparticle gene delivery systems. Also, the authors highlight their philosophy and efforts on the development of l-tyrosine-based polyphosphate nanoparticle-based non-viral gene delivery systems and assess the potential benefits and shortcomings of their approach.