Nanoparticle-mediated systemic delivery of siRNA for treatment of cancers and viral infections.

RNA interference (RNAi) is an endogenous post-transcriptional gene regulatory mechanism, where non-coding, double-stranded RNA molecules interfere with the expression of certain genes in order to silence it. Since its discovery, this phenomenon has evolved as powerful technology to diagnose and treat diseases at cellular and molecular levels. With a lot of attention, short interfering RNA (siRNA) therapeutics has brought a great hope for treatment of various undruggable diseases, including genetic diseases, cancer, and resistant viral infections. However, the challenge of their systemic delivery and on how they are integrated to exhibit the desired properties and functions remains a key bottleneck for realizing its full potential. Nanoparticles are currently well known to exhibit a number of unique properties that could be strategically tailored into new advanced siRNA delivery systems. This review summarizes the various nanoparticulate systems developed so far in the literature for systemic delivery of siRNA, which include silica and silicon-based nanoparticles, metal and metal oxides nanoparticles, carbon nanotubes, graphene, dendrimers, polymers, cyclodextrins, lipids, hydrogels, and semiconductor nanocrystals. Challenges and barriers to the delivery of siRNA and the role of different nanoparticles to surmount these challenges are also included in the review.

Hybrid nanocluster plasmonic resonator for immunological detection of hepatitis B virus.

Approximately 88% of the world population lives in regions with intermediate to high incidence of Hepatitis B virus (HBV), yet current serological and DNA-based detection methods have limited sensitivity and convenience. Here, we describe a preassembled plasmonic resonance nanocluster for HBV detection. The gold nanoparticle acceptors (AuNPs), with HBV surface antigen (HBsAg) epitope, and quantum dot (QD) donors with Fab antibody, are assembled into an immuno-mediated 3D-oriented complex with enhanced energy transfer and fluorescence quenching. The coherent plasmonic resonance between Au and QD nanoparticles is exploited to achieve improved donor-acceptor resonance within the nanocluster, which in the presence of HBV viral particles is disassembled in a highly specific manner. The nanocluster provides high detection specificity and sensitivity of HBV, with a sensitivity limit down to 1-100 viral particles per microliter and to attomolar levels of HBsAg. This general platform could be used to establish multiplex diagnostic assays for a variety of other microbial pathogens.