Viruses are considered as natural nanomaterials as they are in the size range of 20-500 nm with a genetical material either DNA or RNA, which is surrounded by a protein coat capsid. Recently, the field of virus nanotechnology is gaining significant attention from researchers. Attention is given to the utilization of viruses as nanomaterials for medical, biotechnology and energy applications. Removal of genetic material from the viral capsid creates empty capsid for drug incorporation and coating the capsid protein crystals with antibodies, enzymes or aptamers will enhance their targeted drug deliver efficiency. Studies reported that these virus-like nanoparticles have been used in delivering drugs for cancer. It is also used in imaging and sensory applications for various diseases. However, there is reservation among researchers to utilize virus-like nanoparticles in targeted delivery of genes in gene therapy, as there is a possibility of using virus-like nanoparticles for targeted gene delivery. In addition, other biomedical applications that are explored using virus-like nanoparticles and the probable mechanism of delivering genes.
Visual analysis of the gene delivery process when using invasive bacteria as a vector has been conventionally performed using standard light and fluorescence microscopy. These microscopes can provide basic information on the invasiveness of the bacterial vector including the ability of the vector to successfully adhere to the cell membrane. Standard microscopy techniques however fall short when finer details including membrane attachment as well as internalization into the cytoplasm are desired. High-resolution visual analysis of bacteria-mediated gene delivery can allow accurate measurement of the adherence and internalization capabilities of engineered vectors. Here, we describe the use of scanning electron microscopy (SEM) to directly quantify vectors when they are external to the cell wall, and confocal microscopy to evaluate the vectors when they have internalized into the cytoplasm. By performing the invasion procedure on microscope coverslips, cells can be easily prepared for analysis using electron or confocal microscopes. Imaging the invasion complexes in high resolution can provide important insights into the behavior of bacterial vectors including E. coli, Listeria, and Salmonella when invading their target cells to deliver DNA and other molecules.
siRNA technology presents a helpful means of gene silencing in mammalian cells. Advancement in the field includes enhanced attentiveness in the characterization of target and off-target effects employing suitable controls and gene expression microarrays. These will permit expansion in the measurement of single and multiple target combinations and also permit comprehensive efforts to understand mammalian cell processes. Another fact is that the delivery of siRNA requires the creation of a nanoparticulate vector with controlled structural geometry and surface modalities inside the targeted cells. On the other hand, dendrimers represent the class of carrier system where massive control over size, shape and physicochemical properties makes this delivery vector exceptional and favorable in genetic transfection applications. The siRNA therapeutics may be incorporated inside the geometry of the density controlled dendrimers with the option of engineering the structure to the specific needs of the genetic material and its indication. The existing reports on the siRNA carrying and deliverance potential of dendrimers clearly suggest the significance of this novel class of polymeric architecture and certainly elevate the futuristic use of this highly branched vector as genetic material delivery system.