Despite recent progress in the treatment of cancer, far too many cases are still diagnosed only after tumors have metastasized. As a result, patients with cancer face a grim prognosis and often need to endure toxic and uncomfortable whole-body chemotherapy and/or other radiation treatments with the hope that their cancers will be eliminated. If the disease can be detected early enough, statistics have shown that the burden of cancer is drastically reduced. Nanotechnology applied to cancer, by way of nanofunctional materials, is in a unique position to significantly transform the way the disease is diagnosed, imaged, and treated and is the focus of this issue of MRS Bulletin. Materials research in nanotechnology is already successfully implemented in several applications. For instance, photocatalysis using TiO2 nanoparticles is becoming the dominant method for the “self-cleaning” of material surfaces such as glass, ceramics, and fabrics. The nanomaterial carbon nanotubes is a promising candidate in sensor technology and field-emission technology. Our goal is to illustrate the promising new methods being developed in the research community and the challenges that need to be overcome in order to reach clinical utility. More importantly, we hope this issue helps educate and invoke the materials science community to tackle some of the hard issues in diagnosing and treating this disease.

Nanoparticles with a gold shell and iron core have unique optical and magnetic properties that can be utilized for simultaneous detection and treatment strategies. Several nanoparticles have been synthesized and show an ability to mediate a variety of potential applications in biomedicine, including cancer molecular optical and magnetic resonance imaging, controlled drug delivery, and photothermal ablation therapy. However, to be effective, these nanoparticles must be delivered efficiently into their targets. In this review, we will provide an updated summary of the gold-shelled magnetic nanoparticles that have been synthesized, methods for characterization, and their potential for cancer diagnosis and treatment. We will also discuss the biological barriers that need to be overcome for the effective delivery of these nanoparticles. The desired nanoparticle characteristics needed to evade these biological barriers, such as size, shape, surface charge, and surface coating are also explained.

Polymers have been extensively utilized in the design of nanometer-sized delivery vehicles of chemotherapeutics for clinical cancer therapy. Polymeric nanoparticulate delivery vehicles, with chemotherapeutics being either conjugated or encapsulated, have been developed into a variety of different architectures, including polymer-drug conjugates with linear or branched polymers, micelles, and polymersomes. This review describes the progress that has been made in the field of polymeric nanomedicine that brings the science closer to clinical realization of nanopolymeric therapeutics for its application in cancer treatment.

Targeted cancer therapies focus on molecular and cellular changes that are specific to cancer and hold the promise of harming fewer normal cells, reducing side effects, and improving the quality of life. One major challenge in cancer nanotechnology is how to selectively deliver nanoparticles to diseased tissues while simultaneously minimizing the accumulation onto the nanoparticle of unwanted materials (e.g., proteins in the blood) during the delivery process. Once therapeutic nanoparticles have been created, very often they are linked or coated to other molecules that assist in targeting the delivery of nanoparticles to different cell types of the body. These linkers or coatings have been termed targeting ligands or “smart molecules” because of their inherent ability to direct selective binding to cell types or states and, therefore, confer “smartness” to nanoparticles. Likewise, “smartness” can be imparted to the nanoparticles to selectively repel unwanted entities in the body. To date, such smart molecules can consist of peptides, antibodies, engineered proteins, nucleic acid aptamers, or small organic molecules. This review describes how such smart molecules are discovered, enhanced, and anchored to nanoparticles, with an emphasis on how to minimize nonspecific interactions of nanoparticles to unintended targets.

This article provides a brief overview of recent progress in the synthesis and functionalization of magnetic nanoparticles and their applications in the early detection of malignant tumors by magnetic resonance imaging (MRI). The intrinsic low sensitivity of MRI necessitates the use of large quantities of exogenous contrast agents in many imaging studies. Magnetic nanoparticles have recently emerged as highly efficient MRI contrast agents because these nanometer-scale materials can carry high payloads while maintaining the ability to move through physiological systems. Superparamagnetic ferrite nanoparticles (such as iron oxide) provide excellent negative contrast enhancement. Recent refinement of synthetic methodologies has led to ferrite nanoparticles with narrow size distributions and high crystallinity. Target-specific tumor imaging becomes possible through functionalization of ferrite nanoparticles with targeting agents to allow for site-specific accumulation. Nanoparticulate contrast agents capable of positive contrast enhancement have recently been developed in order to overcome the drawbacks of negative contrast enhancement afforded by ferrite nanoparticles. These newly developed magnetic nanoparticles have the potential to enable physicians to diagnose cancer at the earliest stage possible and thus can have an enormous impact on more effective cancer treatment.

Cantilever sensors have attracted considerable attention over the last decade because of their potential as a highly sensitive sensor platform for high throughput and multiplexed detection of proteins and nucleic acids. A micromachined cantilever platform integrates nanoscale science and microfabrication technology for the label-free detection of biological molecules, allowing miniaturization. Molecular adsorption, when restricted to a single side of a deformable cantilever beam, results in measurable bending of the cantilever. This nanoscale deflection is caused by a variation in the cantilever surface stress due to biomolecular interactions and can be measured by optical or electrical means, thereby reporting on the presence of biomolecules. Biological specificity in detection is typically achieved by immobilizing selective receptors or probe molecules on one side of the cantilever using surface functionalization processes. When target molecules are injected into the fluid bathing the cantilever, the cantilever bends as a function of the number of molecules bound to the probe molecules on its surface. Mass-produced, miniature silicon and silicon nitride microcantilever arrays offer a clear path to the development of miniature sensors with unprecedented sensitivity for biodetection applications, such as toxin detection, DNA hybridization, and selective detection of pathogens through immunological techniques. This article discusses applications of cantilever sensors in cancer diagnosis.

In recent years, a new branch of nanoscience/nanotechnology seems to be emerging. This branch is characterized by the application of preparation methods and/or the diagnostic tools developed in nanoscience/nanotechnology in order to perform either new, decisive experiments or to open the way to novel applications in areas of science that were originally not related to nanoscience/nanotechnology, such as cancer research or quantum physics. In order to highlight the diversity of this new branch, we shall discuss the following four areas in which methods of nanoscience/nanotechnology are applied to other areas of science: (1) cancer therapy, (2) cellular labeling, (3) the synthesis of solid materials with tunable atomic structures, and (4) the new opportunities provided by nanoscience/nanotechnology to probe the limits of quantum physics, one of the classical problems of physics.