Abstract There have been significant developments in the use of siRNA in the silencing of cancer-allied target proteins with substantial apoptotic effects. Nevertheless, the challenges regarding siRNA delivery for cancer therapy remain a major concern for taking these therapies successfully from laboratory to in vivo studies. Biomaterials are defined traditionally as any material that is used for either medical or dental applications that contact the host cells in any form, such as a drug carrier a device, or as a prosthesis towards the replacement of damaged tissues. The main issues to be fulfilled by the biomaterial for clinical applications are biocompatibility, bioactivity, ability to carry drug to target site, inflammatory responses and other factors based on its application. The present study focuses on the in vitro inflammatory response to the CS nanoparticles using RAW 264.7 and bone marrow derived macrophage cells. Additionally, the in vitro release kinetics of siRNA with varying concentrations and pH, transfection efficacy and biocompatibility were also investigated. The results of siRNA cumulative release increased at pH 5 and 3, which may be corresponding to the protonation, and a delayed release was seen at 7, which was ascribed to unprotonated amine groups inside the CS. The results of release kinetics confirmed a sustained release of siRNA from CS NPs. Considering that CS is a biocompatible polymer, it typically has little impact/damage on cells, as numerous researchers have observed during in vitro experiments. Inflammatory studies were carried out in vitro with RAW 264.7 and BMC cells derived from mice. The gene and protein expression studies showed that the materials might cause some slight inflammation on exposure with both RAW 264.7 and BMC cells in vitro, which is completely negligible. However, putting together the overall data it can be concluded that CS NPs can be a promising material for in vivo applications, which is in agreement with the results of other researchers, but the only concern being its ability to carry siRNA and protect it from nuclease and other enzymatic attacks.
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