In Vivo Targeted Delivery of Nanoparticles for Theranosis

• Published in: Accounts of chemical research 2011-10, Vol.44 (10), p.1018-1028
• Main Authors: Koo, Heebeom, Huh, Myung Sook, Sun, In-Cheol, Yuk, Soon Hong, Choi, Kuiwon, Kim, Kwangmeyung, Kwon, Ick Chan
• Format: Article
• Language: English
• Subjects: Animals; Biomedical materials; Biotechnology; Chemical Phenomena; Drug Delivery Systems - methods; Drugs; Humans; Imaging; In vivo testing; In vivo tests; Injections, Intravenous; Medical services; Nanoparticles; Nanoparticles - administration & dosage; Nanoparticles - chemistry; Nanoparticles - therapeutic use; Receptors, Cell Surface - metabolism
• ISSN: 0001-4842; 1520-4898
• DOI: 10.1021/ar2000138

Therapy and diagnosis are two major categories in the clinical treatment of disease. Recently, the word “theranosis” has been created, combining the words to describe the implementation of these two distinct pursuits simultaneously. For successful theranosis, the efficient delivery of imaging agents and drugs is critical to provide sufficient imaging signal or drug concentration in the targeted disease site. To achieve this purpose, biomedical researchers have developed various nanoparticles composed of organic or inorganic materials. However, the targeted delivery of these nanoparticles in animal models and patients remains a difficult hurdle for many researchers, even if they show useful properties in cell culture condition. In this Account, we review our strategies for developing theranostic nanoparticles to accomplish in vivo targeted delivery of imaging agents and drugs. By applying these rational strategies, we achieved fine multimodal imaging and successful therapy. Our first strategy involves physicochemical optimization of nanoparticles for long circulation and an enhanced permeation and retention (EPR) effect. We accomplished this result by testing various materials in mouse models and optimizing the physical properties of the materials with imaging techniques. Through these experiments, we developed a glycol chitosan nanoparticle (CNP), which is suitable for angiogenic diseases, such as cancers, even without an additional targeting moiety. The in vivo mechanism of this particle was examined through rationally designed experiments. In addition, we evaluated and compared the biodistribution and target-site accumulation of bare and drug-loaded nanoparticles. We then focus on the targeting moieties that bind to cell surface receptors. Small peptides were selected as targeting moieties because of their stability, low cost, size, and activity per unit mass. Through phage display screening, the interleukin-4 receptor binding peptide was discovered, and we combined it with our nanoparticles. This product accumulated efficiently in atherosclerotic regions or tumors during both imaging and therapy. We also developed hyaluronic acid nanoparticles that can bind efficiently to the CD44 antigen receptors abundant in many tumor cells. Their delivery mechanism is based on both physicochemical optimization for the EPR effect and receptor-mediated endocytosis by their hyaluronic acid backbone. Finally, we introduce the stimuli-responsive system related to the che