Ligands for Tumor Targeting

Cancer is the world's second leading cause of death, and new cancer cases are expected to increase dramatically in the next decades. Many biotechnologists and medical researchers are actively involved in finding issues related to cancer detection and treatment efficacy. Given the difficulties of traditional chemotherapy, the targeted drug delivery system (DDS) of chemotherapeutics for cancer therapy through nanoparticles (NPs) carriers is a growing field of research. Researchers have concentrated on surface modification of NPs or nanocarriers using biological ligands in addition to optimizing their physicochemical characteristics. Several in-vivo investigations have shown that virus-sized stealth NPs may circulate in the blood for a longer period and preferentially concentrate at tumor sites due to the increased permeability and retention (EPR) effect, also known as the passive targeting strategy. Surface modification of stealth NPs with specific biological ligands may result in enhanced retention and accumulation of NPs in tumor sites, referred to as an “active targeting strategy”. This chapter outlined some key points regarding each strategy's impact and how combining some or all of them has proven beneficial in tumor targeting. After a brief introduction to existing cancer treatments and their drawbacks, we discussed the biological obstacles that NPs must overcome, followed by several forms of DDS to increase drug accumulation in the tumor site. Then, using active targeting strategies, we also describe various receptors present on cancer cells that enhance cellular drug targeting. A substantial quantity of information has been summarized in tables on different polymeric NPs conjugated with selective targeting ligands such as proteins, polysaccharides, peptides, and aptamers to small molecules. With the potential of maximizing therapeutic efficacy and reducing side effects, ligandmediated-DDS has emerged as an essential platform for safe and effective tumor treatment.