nanotecnologia y el cancer

Miniaturized Device Puts Nanotechnology to Work in Diagnosing Cancer
An experimental diagnostic device could be a valuable addition to a pathologist’s tool kit for diagnosing cancer, new research suggests. The miniaturized nuclear magnetic resonance, or micro-NMR, device can diagnose cancer within an hour, using patient samples of just a few thousand cells that are collected using a fine needleand a syringe.
Initial clinical studies by researchers at Massachusetts General Hospital (MGH) indicate that the micro-NMR system, which can quantify multiple protein markers in cells from a single patient sample, may be more accurate than standard diagnostic techniques.
A miniaturized nuclear magnetic resonance (NMR) device can detect cancer cells (dark brown) in a small sample of cells from apatient. The coils generate magnetic fields that excite magnetic nanoparticles attached to antibody-protein complexes, resulting in NMR signals that can be used to identify a cancer protein signature. (Image courtesy of H. Lee and R. Weissleder, Massachusetts General Hospital)
Conventional pathology, which is the current gold standard for diagnosing many cancers, is far from perfect. It takesseveral days to yield results, may require surgery to provide enough tissue, is technically challenging, and is subject to human interpretation. A biopsy for conventional pathology may be done either with open surgery, which yields samples containing billions of cells, or with a wide or fine needle. A pathologist processes and stains the tissue sample and examines it under a microscope. If enoughtissue is available, the pathologist may use immunohistochemistry to visualize specific cancer markers in cross-sections of tissue.
The micro-NMR device uses principles similar to those of magnetic resonance imaging (MRI) to detect magnetic nanoparticles attached to antibodies, which flag protein biomarkers known to be associated with some cancers in patient samples. A physician can operate theportable device from the patient’s bedside with a smart-phone application that displays results on the phone’s screen.
Simplicity, Speed, and Sensitivity
The reactions for coupling the magnetic nanoparticle-antibody complexes to specific target proteins are performed at room temperature, and sample processing is simple and quick, the researchers said. In addition to eliminating waiting time, therapid processing is an advantage because experiments showed that protein markers in patient samples degrade quickly.
Micro-NMR probably won’t replace conventional pathology and histology completely, but “it would be a good mechanism to triage patients before they undergo more invasive procedures,” said Dr. Cesar Castro, an oncologist and investigator at MGH. Dr. Castro co-led a recent clinicalstudy that was the first to test the micro-NMR and nanoparticle technologies in patient samples.
The entire micro-NMR system costs about $200 and is roughly the size of a cube-shaped box of facial tissue. Developed by Drs. Hakho Lee and Ralph Weissleder at the Center for Systems Biology at MGH, the system is highly sensitive thanks to miniaturization of the device and the chemistry used to bindmagnetic nanoparticles to their targets. The device can measure levels of individual tumor markers in a 1-microliter sample containing about 200 cells and—unlike technologies that rely on optical properties—works in nonpurified samples.
Advantages in the Clinic
If validated in larger clinical trials, the micro-NMR system could eventually be used not only to diagnose cancer but also to identifypotential patient candidates for targeted therapies and to monitor the response to therapy, Dr. Castro said. When used for diagnosis, this approach could potentially reduce the time that patients are in limbo while waiting for results and provide more information to clinicians, while steering patients away from more invasive procedures and avoiding repeat biopsies, he noted.
“A key advantage of this...