Band 4, Heft 1

RNA interference (RNAi) has been regarded as a vital asset in the field of therapeutics as it has the capability to silence various disease causing genes including those that cause cancer. Small non-coding RNA molecules such as short interfering RNAs (siRNAs) are one of the extensively studied RNAi inducers for gene modulations. However, the delivery of RNAi inducers including siRNAs is compromised due to the barriers imposed by the biological system such as degradation by nucleases, rapid clearance, high anionic charge, immunogenicity and off-target effects. Viral vectors, in general exhibit high transfection efficiencies but are expensive and likely to confer immunological and safety issues. Therefore, non-viral cationic vectors (NVCVs) have received considerable attention to not only address these issues but also for developing efficacious siRNA delivery vectors. In this review, we will first discuss the historical development of various NVCVs and then will discuss functionalized NVCVs with linkers that provide stability, as well as respond to the cancer cell environment and with cancer cell receptor specific ligands to explicitly target them for improved siRNA efficacy. Multifunctional NVCVs (MNVCVs) that employ multiple synergistically working components to aid siRNA delivery efficacy are also discussed.

Fluorescent biosensors typically use energy or electron transfer to modulate the emission from a fluorophore. This requirement often makes it difficult to change the biosensor to make it selective to a difference target. In this research highlight we describe a recently reported strategy that relies, for the first time, on fluorescence blinking from nucleic acid-coupled quantum dots to report the presence of a target molecule. This strategy produces a decoupled biosensor, whose fluorescence output is not directly modulated by interaction with the target. The resulting biosensor can be readily modified to sense any target that can be selectively bound to nucleic acids and is therefore much more widely applicable than the vast majority of fluorescent sensors that have been reported.

Nucleic acids are biocompatible, robust, and highly versatile polymers that can be used to design fine-tunable and dynamically responsive nanostructures. In this report, we focus our attention to recently introduced concepts of interdependent, cognate nucleic acid nanoparticles assembly that take advantage of dynamic interactions and consequent shape-switching to trigger the activation of multiple functionalities. Particularly, we discuss re-association of thermodynamically driven complementary nanocubes (“cube” and complementary “anti-cube”) into functional duplexes that do not require toehold interactions or extensive computational design, bringing a new perspective for utility of nucleic acid nanoparticles as a drug carriers, biosensors, and templates for the formation of siRNA duplexes.