Smart Nanoprobes to locate the Diseases.

Nanoprobes with Quantum dots are programmed with technique, Quenching to illuminate cells with Disease

Quantum Dots are programmed with the technique called 'Quenching' to glow in presence of Enzyme Activity. Researchers from Rice University Center for Biological and Environmental Nanotechnology (CBEN) have developed Smart NanoProbes hundreds of times smaller than a human cell that lights up only when activated by specific proteases (Enzymes that degrade Proteins). Such Enzymes degrading proteins are common in diseases like cancer and atherosclerosis

Development of a this smart nanoprobe for visualization of proteolytic activity in vivo is described in the September Issue of the journal
Biochemical and Biophysical Research Communications. Lead authors of this Research paper are Jennifer West, the Isabel C. Cameron Professor of Bioengineering and director of CBEN's biological research program, and Rebekah Drezek, the Stanley C. Moore Assistant Professor of Bioengineering and assistant professor of electrical and computer engineering.

"The idea is to develop a 'smart' nanostructure that is dark in its original state but lights up very brightly in the presence of enzymatic
activity associated with a particular disease process," said West researcher on Nanoprobes. "Other groups have used targeted nanostructures including quantum dots for molecular imaging, but they have never been able to adequately solve the problem of clearly distinguishing between the 'cancer is here' signal and the background light which arises from nanostructures not specifically bound to their molecular targets."

Research breakthrough is mainly focused at solving the problem to distinguish between disease cell signals and background lights in Molecular Imaging. In the past researchers successfully attempted the experiments to treat cancer cells and other diseases with nanostructures which can break through cell membrane and deliver a drug but they were not successful in pin pointing the cells with disease resulting in approximations in biomedical Imaging. A better known example of this is branching of polymer molecules, called dendrimers, small enough to pass through a cell membrane can be loaded with the anticancer drug methotrexate, the vitamin folic acid, and a fluorescent imaging agent to treat cancer. This technique is definitely many times effective than conventional chemotherapy which harms healthy cells also.

Researchers at Rice University solves this problem in molecular imaging with the use of emissive nanoparticles called quantum dots that emit light in near infrared region (NIR). NIR is a band in the electromagnetic spectrum which is free of any background component and also harmless through living tissues in the skin. Such Smart Nanoprobes with nanoparticle techniques to treat diseases like cancer will increase effectiveness of drugs to fight killer diseases.

Design of Smart Nanoprobes binds the gold nanoparticle to the quantum dot to inhibit luminescence. The Bind is made up of Peptide sequence few nanometers in length, ties the gold nanoparticle close enough to quantum dot to prevent the quantum dot from giving off its light.

At Rice University, Team of Researchers working on Nanoprobes used a peptide (a Protein fragment with chain of two or more amino acids) bond that is segmented by the enzyme collagenase (type of enzyme that breaks down the protein collagen). Nanoprobe researchers showed that 70% of the light emission from quantum dots is cut off when they are bonded with gold nanoparticles. These quantum dots remained dark until they are exposed to enzyme which can break peptide bonding, and quantum dots start emitting light after that making probing possible. Ultimately, the nanoprobes researchers hope to pair a series of quantum dots, each with a unique NIR optical signature, to an index of linker proteases.

"There is currently a critical need for methods to simultaneously image the activity of multiple proteases in vivo," said Drezek. "This is
important not only for early detection of several diseases, but perhaps more significantly, in understanding and monitoring the efficacy of
therapeutic interventions, including the growing class of drugs that act as protease inhibitors. What is particularly powerful about the protease imaging probes described in this study is the combination of the contrast enhancement achievable through an activateable probe with the imaging advantages provided by the brightness, photostability, and tunability of quantum dots."

Smart Nanoprobes could prove gifted lenses for human or any living organism which can peep into cell membranes locate the deformed cells and also provide long hidden knowledge of cellular dynamics, they can be most powerful detection techniques for cells with protease almost like a computer antivirus systems for which one can download patches with definitions for new virus, sounds exciting. Smart Nanoprobes are promising advancement in medical science and Molecular Imaging.

The original news release can be found here