The Smart Targeting of Nanoparticles

Abstract

One major challenge in nanomedicine is how to selectively deliver nanoparticles to diseased tissues. Nanoparticle delivery system requires targeting for specific delivery to pathogenic sites when enhanced permeability and retention (EPR) is not suitable or inefficient. Functionalizing nanoparticles is a widely-used technique that allows for conjugation with targeting ligands, which possess inherent ability to direct selective binding to cell types or states and, therefore, confer “smartness” to nanoparticles. This review illustrates methods of ligand-nanoparticle functionalization, provides a cross-section of various ligand classes, including small molecules, peptides, antibodies, engineered proteins, or nucleic acid aptamers, and discusses some unconventional approaches currently under investigation.

Nanoparticles Carrying Biological Molecules: Recent Advances and Applications

“…Furthermore, nucleic acids have a unique ability to self-assemble into compact and stable structures with precise control over the nanoparticle size, geometry, and composition (Panigaj M. and Reiser J., 2016). The current research in the development of bio-based nanoparticles have shown that the DNA and RNA nanoparticles can be utilised as scaffolds and can be tagged with various types of biological and therapeutic compounds such as aptamers, fluorophores, and oligonucleotides to carry its desired function (Friedman A.D. et al, 2013;Panigaj M. and Reiser J., 2016).…”

Smart multifunctional nanoparticles in nanomedicine

“…Immunogenicity, stability, and difficulties in site-specific conjugations with nanoparticles are the major obstacles in targeting ligands. Monoclonal antibodies (mAbs) are widely preferred targeting ligands because of their availability to research and their high affinity and specificity for molecular targets [49,50]. Several mAbs have been used in clinics for cancer therapy, such as bevacizumab (against colorectal cancer) and trastuzumab (against breast cancer) [51].…”

“…Aptamers can be synthesized with a specific functional moiety, such as a carboxylate, amino or sulfhydryl at only one end of the nucleic acid sequence of the aptamer. They are small in size and non-immunogenic [50,53]. Peptides are an attractive alternative as targeting molecule due to several advantages, including a smaller size, a lower immunogenicity, a higher tissue penetration capability, a higher stability and a relatively easy production process.…”

Peptide-Based Cancer-Targeted DDS and Molecular Imaging

“…[10][11][12] The application of the ligands to anticancer drugs is a rational approach for drug delivery systems (DDS) by directly conjugating to small molecular drugs or formulating nanoparticle-encapsulated small molecular drugs, nucleic acids, peptides, and proteins. 13,14) In addition, this approach is effective in molecular imaging that enables us to visualize tumor cells or their microenvironments in positron-emission tomography (PET), single photon-emission computed tomography (SPECT), magnetic resonance imaging (MRI), and optical imaging. 14) Among ligands, peptides obtained from endogenous protein sequences are relatively safe and show low immunogenicity, in addition to structural simplicity.…”

“…13,17) Nanoparticles (<200 nm) are nonspecifically leaked to tumor cells due to the enhanced permeability and retention (EPR) effect occurring with increasing tumor vascular permeability. [18][19][20] The modification of nanoparticles with peptide ligands enables their specific accumulation in target organs and tumor cells by receptormediated uptake such as endocytosis.…”