Gold nanoparticle-based anodic stripping voltammetry detection of transcription factor NF-kB

Transcription factor and sequence specific DNA interactions play important roles in drug genome and transcription diagnosis. Gold nanoparticles show high sensitivity, stability and compatibility for biological molecules as electrochemical intercalators. Here unimolecular hairpin oligonucleotides were self-assembled onto Au electrode surface and elongation on solid phase was carried out to double strand oligonucleotides with transcription factor NF-r,13 binding site. Gold nanoparticle-catalyzed Ag deposition was detected by anodic stripping voltammetry （ASV） for NF-kB binding. It was indicated that this method for sequence specific DNA binding protein detection shows pronounced specificity, sensitivity and we can find application in transcription regulation research, open reading frame characterization and functional gene inspection by this method.

Optimizing surface-engineered ultra-small gold nanoparticles for highly efficient miRNA delivery to enhance osteogenic differentiation of bone mesenchymal stromal cells

Regulation of osteogenic differentiation of bone mesenchymal stromal cells （BMSCs） plays a critical role in bone regeneration. As small non-coding RNAs, microRNAs （miRNAs） play an important role in stem cell differentiation through regulating target-mRNA expression. Unfortunately, highly efficient and safe delivery of miRNAs to BMSCs to regulate their osteogenic differentiation remains challenging. Conventional inorganic nanocrystals have shown increased toxicity owing to their larger size precluding renal clearance. Here, we developed novel, surface-engineered, ultra-small gold nanoparticles （USAuNPs, 〈10 nm） for use as highly efficient miR-5106-delivery systems to enable regulation of BMSC differentiation. We exploited the effects of AuNPs coated layer-by-layer with polyethylenimine （PEI） and liposomes （Lipo） to enhance miR-5106-delivery activity and subsequent BMSC differentiation capacity. The PEI- and Lipo-coated AuNPs （Au@PEI@Lipo） showed negligible cytotoxicity, good miRNA-5106-binding affinity, highly efficient delivery of miRNAs to BMSCs, and long-term miRNA expression （21 days）. Additionally, compared with commercial Lipofectamine 3000 and 25 kD PEI, the optimized Au@PEI@Lipo-miR-5106 nanocomplexes significantly enhanced BMSC differentiation into osteoblast-like cells through activation of the Sox9 transcription factor. Our findings reveal a promising strategy for the rational design of ultra-small inorganic nanoparticles as highly efficient miRNA-delivery platforms for tissue regeneration and disease therapy.

Biomimetic gold nanocomplexes for gene knockdown： Will gold deliver dividends for small interfering RNA nanomedicines？

RNA interference （RNAi） effectors such as small interfering RNA （siRNA） and micro RNA （miRNA） can selectively downregulate any gene implicated in the pathology of a disease. Therefore, RNAi-based therapies have immense potential for the treatment of a wide range of diseases. However, pharmacokinetic and pharmacodynamic studies have revealed that these therapeutic agents have poor bioactivity due to a number of factors, including insufficient plasma drug levels, short plasma half-lives, renal clearance, and hepatic metabolism. Non-viral delivery may facilitate the clinical application of siRNA-based therapeutics by helping to overcome these barriers. Recently, the potential of gold nanoparticles （AuNPs） as multifunctional carriers for transporting drugs, proteins, and genetic materials has been demonstrated. In this review, some of the key properties of AuNPs relevant to siRNA delivery, such as physical properties and surface chemistry have been described. In addition, the ability of AuNP-based formulation strategies to successfully overcome delivery barriers associated with siRNA, and the potential for this material to translate into safe and effective nanomedicines are critically discussed.