**4.4 Gene delivery applications of chitosan-based nanocomposites**

Gene therapy holds promise for challenging disease therapy such as innate genetic diseases [115], infections [116], and cancer [117]. A serious step for gene therapy is the gene's successful delivery. Naked nucleic acids cannot cross the cell membrane and are simply reduced by serum nucleases. Therefore, safe and efficient gene delivery systems are crucial for the accomplished application of gene therapy. Safety concerns about immunogenicity and toxicity are the key difficulties for the common use of viral systems [118]. Amongst virus-related vectors, adeno-associated virus (AAV) is now the most common gene delivery vector since it seldom includes the host genome, however, aggregate can be sensed [119, 120]. No viral vectors are good options for gene delivery

### *Chitosan-Based Nanocomposites for Biological Applications DOI: http://dx.doi.org/10.5772/intechopen.106379*

because of their no genotoxicity, scalable manufacture, and structural elasticity [121]. They have been used in studies related to RNAi [122], gene editing [123], and CAR-T cell treatment [124]. No viral vectors are used more regularly in cancer treatment than in other uses for cancer and are a key worldwide public health matter [125]. Chitosan and its derivatives are commonly used to formulate gene delivery vectors. Various studies have been conducted to theory gene vectors based on chitosan. This assessment will argue the present development of policies encouraging the restrictions and chitosan applications in gene delivery systems and upcoming forecasts [126].

Gene therapy has developed very promptly due to its incredible healing possible to treat various genetic diseases by the inclusion of new genes (DNA and RNA) into target cells with transgene expression. Yet, the in vivo delivery of naked healing genes is unrealistic and tense with difficulties, including the gene susceptibility degradation by nucleases in the plasma, non-specificity to directed cells, in addition to the incapability of the negative genes from incoming negative cellular membranes. Certainly, with nearly 2600 gene therapeutics having finalized or ongoing medical trials, about six genes healing has received confirmation in the west [127, 128]. It is approved that the administration of the naked gene either systemically or locally is not effective, because of the concerns mentioned above. Consequently, the simple difficulties for gene treatment is the safe development and efficient gene transfection vector (**Figure 5**) [129].

#### **4.5 Bio-imaging applications**

Chitosan is a naturally happening amino-polysaccharide, with tempting physiochemical and biological features, gotten from the deacetylation of chitin, the secondhighest biopolymer contemporary in the world afterward cellulose. The amino and hydroxyl groups current on the skeleton of chitosan deliver a route for reaction with

#### **Figure 5.** *Gene delivery in the cancer therapy (https://biorender.com/).*

organic practical molecules [130]. Moreover, chitosan is used as a biomaterial due to its outstanding biodegradability and low toxicity. Also used as bio imaging agent [131]. The introduction of imaging agents in chitosan permitted its use for bioimaging. Such as the integration of imaging agents, for example, Fe3O4 figure magnetic resonance imaging; the self-assembled nanoparticles improve the perception of hepatocyte targeted imaging [132]. Chitosan decreased gold nanoparticles have performed as photo thermalconverter, photodynamic-treatment besides photodynamics carrier and thus figure in the bio-imaging implementation plus used to annihilate the breast cancer cells (MCF-7) [133]. Gold-covered Fe3O4 nanoparticles were made by chemical co-precipitation technique with an average size of 9.8 nm in diameter by the decrease of glucose and stabilized with chitosan in the face of formaldehyde as a crosslinking agent. The prepared nanomaterial performed as well substantial for bio establisher applications [134, 135].
