https://www.selleckchem.com/products/pnd-1186-vs-4718.html The potential of RNAi therapies has been largely impeded by the inherent challenges in the functional delivery of siRNA to cells. Herein, we describe protocols for the synthesis and characterization of novel peptide-siRNA nanoparticles prepared from disulfide-constrained amphipathic peptides complexed with siRNA as promising siRNA delivery vectors. We also describe protocols for the application of these nanoparticles to the in vitro and in vivo delivery of siRNA to lung cells for the functional knockdown of lung proteins.Efficient gene transfer is necessary for advanced biotechnologies ranging from gene therapy to synthetic biology. Peptide nanoparticles provide suitable packaging systems promoting targeted gene expression or silencing. Though these systems have yet to match the transfection efficacy of viruses, they are typically devoid of drawbacks characteristic of virus-based vectors, including insertional mutagenesis, low packaging capacities, and strong immune responses. Given the promise nanoparticle formulations hold for gene delivery, methods of their preparation and accurate analysis of their physicochemical and biological properties become indispensable for progress toward systems that seek to outperform viral vectors. Herein, we report a comprehensive protocol for the preparation and characterization of archetypal peptide nanoparticles resulting from nonspecific and noncovalent complexation with RNA and DNA.Covalently linking together different proteins can enhance functionality for a range of applications. We have developed the SnoopLigase peptide-peptide conjugation method to easily and specifically link proteins fused to the peptides SnoopTagJr or DogTag via an isopeptide bond. SnoopLigase conjugation has been applied for enhancing enzyme resilience and for antigen oligomerization to enhance vaccine efficacy. Following conjugation, SnoopLigase and unreacted substrates can be removed by solid-p