The Nanotechnology Characterization Laboratory (NCL) performs and standardizes the pre-clinical characterization of nanomaterials intended as cancer therapeutics and diagnostics developed by researchers from academia, government, and industry. The NCL serves as a national resource and knowledge base for cancer researchers, advancing nanotechnology science to facilitate the development and translation of nanoscale particles and devices for clinical applications.
The NCI believes that the NCL's activities will markedly speed the development of nanotechnology-based products for cancer patients, reduce the risk of doing so, and encourage private-sector investment in this promising area of technology development. By achieving its goals the NCL will provide a comprehensive set of baseline characterization parameters that will enable cancer biologists, drug and diagnostic developers, and clinical oncologists to apply their tools to solving problems that most affect cancer patients. This work will also lay a scientific foundation that will enable the FDA to make sound decisions concerning the testing and approval of nanoscale cancer diagnostics, imaging agents, and therapeutics.
To achieve its Mission, the NCL has established the following four objectives:
- Characterize nanoparticles using standardized methods
The NCL will develop and maintain a standardized analytical cascade that characterizes nanoparticles' physical and chemical attributes, their in vitro biological properties, and their in vivo compatibility with preclinical toxicology, pharmacology, and efficacy studies. A nonexhaustive list of the assays and equipment used for nanoparticle characterization at the NCL is available for reference.
Current research on therapeutic and diagnostic applications for nanomaterials is helping to identify critical parameters for the material's compatibility with biological systems. Extant literature implicates physical attributes such as size, hydrophilicity, and surface chemistry as key factors contributing to a nanomaterial's in vivo fate. The first phase of the analytical cascade will therefore focus on the characterizing of the material's physical and chemical properties. The goal of this phase is to determine the particle's size, size distribution, molecular weight, density, surface area, porosity, hydrophilicity, surface charge density, purity, surface chemistry, and stability. The batch-to-batch reproducibility of material as provided by the sponsor/vendor will also be addressed during this stage.
In Vitro Characterization
Prior to filing an Investigational New Drug (IND) or Investigational Device Exemption (IDE) application with the FDA, a new product must be adequately studied. For these products, toxicity or biocompatibility must first be characterized in animals and efficacy may be standardized in animal discovery models. The cost- and labor-intensiveness of these in vivo studies impel drug and device discovery efforts to utilize in vitro methodologies wherever technology permits. Refined in vitro protocols related to drug and device discovery allow researchers to make a first-order assessment of a material's in vivo pharmacokinetics, biocompatibility, and toxicity.
Nanoparticles' binding, pharmacology, and uptake properties, for example, will be monitored by common cell and molecular biology methods, such as ELISA and fluorescence microscopy. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) will also be used as tools to observe the particle's interaction with cellular-level components. Electron microscopy, chromatography and electrophoresis protocols allow the NCL to characterize the nanomaterial's blood contact properties, such as opsonization and macrophage phagocytosis as well as pinocytosis and uptake by nonphagocytic cells.
Also included in the in vitro characterization is a thorough examination of the nanoparticle’s hematocompatibility, compatibility with components of the immune system, and the therapeutic and/or diagnostic functionality. For example, particles with imaging modalities will be examined for their signal intensity (i.e., signal-to-noise ratio); nanotechnology strategies that incorporate therapeutic or preventative agents will be characterized for their drug-release kinetics and ability to cross biological barriers.
In vitro models can also serve as a gross approximation of a nanomaterial's absorption, distribution, metabolism, excretion and toxicity (ADME/Tox) properties. For example, an initial assessment of acute toxicity can be conducted using hepatic microsomes, primary bone marrow cultures (GM-CFU), or mitochondrial toxicity assays. Other cellular assays to monitor apoptosis and cytotoxicity are now commonplace. As an example of pharmacokinetic characterization, release curves from nanoparticles with drug delivery strategies will be obtained and then assessed against other standardized release models, such as insulin.
In Vivo Characterization
The primary goal of the in vivo characterization is to elucidate the nanomaterials' safety, efficacy, and toxicokinetic properties in animal models. As is the case with any new chemical entity (NCE), these properties and other ADME data must be obtained prior to transitioning the nanoparticles to clinical applications. This phase will leverage the plethora of knowledge gained in the in vitro characterization stage to characterize the drugs and devices in vivo.
Animal studies conducted under the in vivo phase for the study of nanoparticles will be in support of the FDA's Guidance For Industry, Single Dose Acute Toxicity Testing For Pharmaceuticals. The nanoparticle will be administered to animals to identify (1) doses causing no adverse effect and (2) doses causing life-threatening toxicity. The information obtained from these tests will provide preliminary identification of target organs of acute toxicity, and may aid in the selection of starting doses for Phase I human trials. In vivo studies will also characterize the nanoparticle absorption, pharmacokinetics, serum half-life, protein binding, tissue distribution/ accumulation, enzyme induction or inhibition, metabolism characteristics and metabolites, and excretion pattern.
Given the multifunctional potential of nanoparticles, the in vivo characterization phase will also include an assessment of the strategy's targeting and/or imaging capabilities. Targeting will be assessed, for example, by comparing a nanoparticle distribution profile with a non-targeting nanoparticle from the same class. For those particles used with imaging modalities, the signal enhancement will be monitored using the appropriate magnetic resonance, ultrasound, optical, positron emission tomography imaging instrumentation. The NCL will actively collaborate with NCI's Cancer Imaging Program (CIP) to facilitate and harmonize the NCL studies with imaging strategies to be used in clinical trials.
NCI's Developmental Therapeutics Program (DTP) is an example of an in vivo program already in place at NCI at Frederick that can augment the NCL programs. DTP accepts candidate drugs from intramural and extramural investigators and then subjects these compounds to an extensive series of animal studies. These studies include determining the drug's maximum tolerated dose (MTD), its biological effective dose (BED), its toxicity to cardio-, hematopoetic, neurological, and nephritic tissues, and its efficacy in a variety of animal and tumor models.
Another NCI program that conducts preclinical studies using animal models is the NCI Experimental Therapeutics Program (NexT) program. NExT is a competitive program to expedite and facilitate the development of promising drugs from the laboratory to IND status. The NExT program provides preclinical resources and testing to facilitate IND filing of novel therapeutics to meet needs not adequately addressed by the private sector.
- Conduct structure activity relationship (SAR) studies
The analytical cascade developed at the NCL is structured to characterize specific nanotechnology strategies that are submitted to the NCL. Concurrent with that effort will be research directed at elucidating the critical parameters that influence nanomaterials' compatibility and effectiveness in biological systems. For instance, a growing body of evidence implicates nanomaterials' size, surface chemistry, fluid dynamics, and hydrophilicity as key parameters contributing to its distribution and excretion. By determining the influence of each of these parameters (i.e., the partial derivative), the NCL will work toward a better understanding of structure activity relationships (i.e., the total derivative). A systematic characterization of these parameters' influence on in vitro/in vivo ADME/Tox profiles will provide empirical data to engineering and predictive models. These modeling tools may predict and recommend functionalization and structural improvements, which can then be incorporated into the next iteration of nanomaterials submitted to the NCL.
- Facilitate regulatory review of nanotech constructs
In order to accelerate the transition of basic nanotechnology research to clinical applications, the NCL works closely with regulatory bodies, primarily the FDA, as it assists industry to navigate through preclinical tests and clinical trials. The FDA refers to this multidimensional product development and evaluation in terms of "critical path" and "critical path research." The former refers to the path from discovery or design concept through clinical evaluation to widespread clinical application; the latter is directed toward improving the product development process itself by establishing new evaluation tools. The NCL seeks to facilitate both the critical path itself and the development of critical path evaluative tools for medical product development.
In support of the critical path, the NCL will perform preclinical characterization of nanomaterials intended for clinical trials. The rigorous and thorough analytical cascade used by NCL will contribute to the scientific quality of data submitted in the IND/IDE application package; the lack thereof is the major cause of delays in IND/IDE approval. More specifically, the NCL will generate quality data in support of paragraphs (7) "Chemistry, manufacturing, and control information" and (8) "Pharmacology and toxicology information" in 21 CFR 312.23, "IND Content and Format."
The relationship with the FDA is also crucial for NCL interaction with industry. Industry presently assumes significant risk in R&D for nanomaterials intended for clinical applications; the regulatory guidelines for nanomaterials are not always clearly defined. A standardized analytical cascade, developed in collaboration with NIST and FDA, is intended to "incentivize" industry to submit nanomaterials to the NCL for characterization, thereby reducing the high risks associated with regulatory approval. FDA itself, as a result of changes introduced by the Modernization Act of 1997, has increased flexibility in classifying new medical devices (including diagnostics), a technique called de novo classification. The FDA also has a broadened tool box of regulatory tools including modular PMAs, special and abbreviated 510(k)s, real-time reviews, and expedited reviews.
It is also anticipated that much of NCL's preclinical characterization will be amenable to the use of Drug Master Files (DMF), a submission to the FDA that permits other users to reference the study (see 21 CFR 314.420). The NCL, through the NCI, could therefore submit core nanoparticle analysis and characterization results to a DMF. Subsequent nanotechnology strategies that rely on that core nanoparticle (e.g., dendrimers) could then reference the DMF in their INDs.
- Engage in educational and knowledge sharing efforts
The NCL is intended to serve as a nexus for transdisciplinary research, development, and clinical applications of nanotechnology. This cross-disciplinary nature provides a unique opportunity to educate and train scientists in the field of nanotechnology. It is anticipated that graduate students, postdocs, and scientists from the disciplines of material science, engineering, physics, chemistry, pharmacology, toxicology, immunology, and cancer research will be able to conduct and contribute to research in the nanotech field. High school and college students interested in learning more about nanotechnology can find internship opportunities through the NCI at Frederick website here. Researchers interested in doing a post-doctoral fellowship with the NCL can find openings on the Leidos website here. Visiting scientist sabbaticals are also occasionally offered, as time and resources permit. To request more information on these opportunities, please contact the NCL with a description of your interests.
The NCL will disclose relevant findings and trends to the scientific community and the public through journal publications, scientific conferences, public forums, the internet, and press releases. Care will be taken, however, to ensure a sponsor’s proprietary information is protected in accordance with the terms of any agreements (e.g., Material Transfer Agreement). A list of NCL publications can be found here.
Additionally, the NCL occasionally sponsors seminars and workshops to familiarize and equip intramural and extramural researchers with nanotechnology protocols and capabilities. Specifically, the NCL offers a Lessons Learned Workshop approximately every two years. The workshop is designed to update researchers on the “lessons learned” from NCL’s testing of candidate nanomedicines. Information on upcoming events will be posted on NCL’s website as available, and will also be distributed through NCL e-News alerts.