Nanomaterials Facilitate Tumor Targeting and Drug Delivery

Review Article

Austin J Cancer Clin Res. 2016; 3(2): 1072.

Nanomaterials Facilitate Tumor Targeting and Drug Delivery

Peng X1,2, Rahman MA1,2, Mao H2,3 and Shin DM1,2*

¹Department of Hematology and Medical Oncology, USA

²Emory Winship Cancer Institute, USA

³Department of Radiology and Imaging Sciences, Emory University School of Medicine, USA

*Corresponding author: Shin DM, Winship Cancer Institute, Rm 3090, 1365-C Clifton Road, Atlanta, GA 30322, USA

Received: November 23, 2016; Accepted: December 29, 2016; Published: December 30, 2016


Current anticancer therapeutic drugs are restricted by: 1) relatively lower drug concentrations in tumor tissues; 2) lack of targeted delivery; 3) side effects resulting from the nonspecific accumulation of drugs in normaltissues; 4) acquired drug resistance. The targeted or selective delivery of anticancer drugs to tumor cells by nanoparticles has been demonstrated to potentially reduce the limitations of current drug delivery. In recent years, the development of tumor-targeted nanoparticles as the next generation of drug carriers has been extensively studied. Results from largely preclinical studies of various types of engineered nano carriers show that targeted nanomaterial-facilitated delivery may further increase the intracellular accumulation of drugs and improve their antitumor effects compared with non-targeted nanoparticles. However, developing tumor-targeted nanoparticles for selective anticancer delivery in vivo requires further understanding on how nanoparticle carriers behave and function in the complex biological systems, various physiological conditions and heterogeneous tumor microenvironment in order to better design and functionalize a nanoparticle delivery system. In this review, we will focus on tumor targeting strategies with discussions on tumor specific biomarkers, promising nanomaterials developed and tested for targeted delivery of therapeutics and imaging, and important issues and challenges for future clinical applications in oncology.

Keywords: Tumor; Drug Delivery; Nanomaterial


Tumor targeting is a key strategy in personalized cancer diagnosis and treatment. The concept of tumor targeting was originally proposed decades ago to guide the development of “tumor seeking missiles” or “magic bullets” for cancer treatment [1]. With our increasing understanding of tumor biology and physiology at cellular and molecular levels and the discovery of new biomarkers and target specific treatment and drugs, tumor targeting is now applied in many major areas of cancer management, including diagnostic imaging, drug delivery and, most recently “theranostics”, which combines both diagnosis and therapy [2-6] in a shared platform. In parallel with tremendous advances in biomedical engineering, tumor biology and molecular oncology, one major focus in biomedical research is the development of new functional materials that enable highly efficient tumor targeting for imaging and delivery of therapeutic agents. Novel nanotechnologies and nanomaterials with unique properties and functions have increasingly shown capabilities and advantages in tumor targeted applications, particularly in the effort to overcome the challenges and limitations of tumor targeted anticancer drug delivery [7-10]. With tremendous progress made in the last decade some of the nanoparticles have already been approved by the FDA or are in clinical trials [11,12].

Conventional drug delivery routes applied in most current clinical practices include oral, transdermal, transmuscular and intravenous delivery, which are not designed to specifically target to certain cancer cells or cells with specific molecular characteristics.

In contrast, drug delivery with engineered nanoparticles can be accomplished in a targeted fashion using both passive and active targeting strategies as illustrated in Figure 1. Passive targeting takes advantage of the enhanced permeability and retention effect (EPR) [13,14] from leaky blood vessels and limited lymphatic drainage in tumors, which are commonly associated with tumor growth, to increase the accumulation of drug-carrying nanoparticles in the tumor mass. Thus, passive targeting enhances the anti-tumor effects and reduces the side effects of cytotoxic agents through changing the distribution and pharmacokinetics of nanoparticle-loadeddrugs without using tumor targeted ligands.