In recent years, much more attentions have been focused on siRNA-based gene therapy. This approach is based on PTGS (Post-transcriptional gene silencing). Due to some defects in viral vectors, non-viral vectors have been used to deliver nucleic acids into target cells. Although, transfection efficiency in non-viral vectors is less than viral ones, but safety of non-viral vectors is much more. Characteristic features of siRNA, such as high compatibility, application in low doses and its versatility make it suitable in the gene therapy field. However, some challenges, such as stimulating immune system and Off-target silencing will be remain. In this review article, we express bottlenecks existing in siRNA delivery into target cells. According to the information, with further development of siRNA delivery in the future, it could be a promising approach in treatment for a variety of genetic diseases.

In this paper, recommended spiral passive micromixer was designed and simulated. spiral design has the potential to create and strengthen the centrifugal force and the secondary flow. A series of simulations were carried out to evaluate the effects of channel width, channel depth, the gap between loops, and flowrate on the micromixer performance. These features impact the contact area of the two fluids and ultimately lead to an increment in the quality of the mixture. In this study, for the flow rate of 25 μl/min and molecular diffusion coefficient of 1×10-10 m2/s, mixing efficiency of more than 90% is achieved after 30 (approximately one-third of the total channel length). Finally, the optimized design fabricated using proposed 3D printing method.

Several plant extracts and phytoconstituents, despite having excellent bioactivity in vitro, demonstrate less or no in vivo actions due to their poor lipid solubility or improper molecular size or destruction in gut. Drug delivery system for polyphenolic phytoconstituents (phytosomes) was prepared by complexing polyphenolic phytoconstituents with phospholipid mainly phosphatidylcholine which bind components to each other on a molecular level. Bioavailability is enhanced due to their capacity to cross the lipid rich bio-membranes and to protect the valuable components of the herbal extract from destruction by digestive secretions and gut bacteria. Phytosomes have the capacity to deliver the standardized plant extracts and phytoconstituents through several routes of drug administration. Only a few natural drugs have been formulated and are available in the market as phytosomes. With wide range of applications of phytosomes numerous studies are undergoing and lots more is expected in the forthcoming years. The techniques used for such formulations are patentable and highly profitable.