How To Capture Quickly Cancer Markers

A nanoscale product of human cells that was once considered junk is now known to play an important role in intercellular communication and in many disease processes, including cancer metastasis. Researchers at Penn State have developed nanoprobes to rapidly isolate these rare markers, called extracellular vesicles (EVs), for potential development of precision cancer diagnoses and personalized anticancer treatments.

Lipid nanoprobes

Most cells generate and secrete extracellular vesicles,” says Siyang Zheng, associate professor of biomedical engineering and electrical engineering. “But they are difficult for us to study. They are sub-micrometer particles, so we really need an electron microscope to see them. There are many technical challenges in the isolation of nanoscale EVs that we are trying to overcome for point-of-care cancer diagnostics.”

At one time, researchers believed that EVs were little more than garbage bags that were tossed out by cells. More recently, they have come to understand that these tiny fat-enclosed sacks — lipids — contain double-stranded DNA, RNA and proteins that are responsible for communicating between cells and can carry markers for their origin cells, including tumor cells. In the case of cancer, at least one function for EVs is to prepare distant tissue for metastasis.

The team’s initial challenge was to develop a method to isolate and purify EVs in blood samples that contain multiple other components. The use of liquid biopsy, or blood testing, for cancer diagnosis is a recent development that offers benefits over traditional biopsy, which requires removing a tumor or sticking a needle into a tumor to extract cancer cells. For lung cancer or brain cancers, such invasive techniques are difficult, expensive and can be painful.

Noninvasive techniques such as liquid biopsy are preferable for not only detection and discovery, but also for monitoring treatment,” explains Chandra Belani, professor of medicine and deputy director of the Cancer Institute,Penn State College of Medicine, and clinical collaborator on the study.

We invented a system of two micro/nano materials,” adds Zheng. “One is a labeling probe with two lipid tails that spontaneously insert into the lipid surface of the extracellular vesicle. At the other end of the probe we have a biotin molecule that will be recognized by an avidin molecule we have attached to a magnetic bead.”


Understanding The Risks Of Nanotechnology

When radioactive materials were first introduced into society, it took a while before scientists understood the risks. The same is true of nanotechnology today, according to Dr Vladimir Baulin, from University Rovira i Virgili, in Tarragona, Spain, who together with colleagues has shown for the first time how nanoparticles can cross biological – or lipidmembranes in a paper published in the journal Science Advances
Nanotechnology is all around us, in building materials, in toothpaste and in cleaning products. Across Europe, hundreds of institutions are working together to look at how to monitor exposure, manage the risks and advise on what regulations may be needed under the EU’s NanoSafety Cluster.

nanoparticles effects on lipids

This is the first observation to show directly how tiny gold nanoparticles can cross a lipid bilayer (main part of a biological membrane). This process was quantified and the time of each step was estimated. The lipid membrane is the ultimate barrier protecting cells from the outside environment and if the nanoparticles can cross this barrier they may go into cells.’

‘Dr Jean-Baptiste Fleury (from Saarland University in Germany) designed a special set-up with two chambers separated by a lipid bilayer, which contained fluorescent lipids (fat molecules). Non-fluorescent nanoparticles were added to only one of the chambers. In this set-up, nanoparticles became visible only when they touched the fluorescent bilayer and exchanged lipids with it. If one sees the fluorescent nanoparticle in the second chamber, this means it was in contact with the bilayer and it crossed the bilayer from one chamber to another. This was the proof. In addition, the process of translocation was quantified and the time of the crossing was estimated as milliseconds.’

All biological objects, biomolecules, proteins that exist in living organisms evolved over billions of years to adapt to each other. Nanoparticles which are synthesised in the laboratory are thus considered by a living organism as something foreign. It is a big challenge to make them compatible and not toxic.’ ‘I would count the applications of nanoparticles as starting from the 1985 Nobel Prize for the discovery of fullerenes (molecules of hollow football-shaped carbon). This was the start of the nanoparticle boom.’

This is becoming urgent because nanoparticles and nanotechnology in general are entering our lives. Now it is possible to synthesise nanomaterials with precise control, fabricate nanostructures on surfaces and do precise tailoring of the properties of nanoparticles.

‘It is becoming quite urgent to understand the exact mechanisms of nanotoxicity and make a classification depending on the mechanism. Radioactivity or X-rays entered our lives the same way. It took time until researchers understood the mechanisms of action on living organisms and the regulations evolved with our understanding.’

gold nanoparticles cross the membrane

This is the first observation to show directly how tiny gold nanoparticles can cross a lipid bilayer.

An empirical test of toxicity is that you put nanoparticles into the cells and you see the cells are dead, but you don’t understand what has happened, this is empirical. This is a legitimate tool, but it is not enough to address toxicity. Instead, one could start from the properties of nanoparticles and think about classifying nano-objects based on their physical or chemical properties by trying to predict the effect of a given nanoparticle on a cell or tissue beforehand.

I understand, it may look too ambitious, since there are a lot of tiny details that are not considered at the moment in theoretical models or any classification. However, even if it may not be exact, it can give some guidance and it would be possible to make predictions on how nanoparticles and polymers interact with lipid membranes. For example, in this study we used theoretical modelling to suggest the size and surface properties of the nanoparticle that is able to cross the lipid membrane through a certain pathway and it was observed experimentally.’


How To Follow Nanoparticles In The Body

Treating a disease without causing side effects is one of the big promises of nanoparticle technology. But fulfilling it remains a challenge. One of the obstacles is that researchers have a hard time seeing where nanoparticles go once they’re inside various parts of the body. But now one team has developed a way to help overcome this problem — by making tissues and organs clearer in the lab. Their study on mice appears in the journal ACS Nano.

3D mapping of nanoparticle

Scientists are trying to design nanoparticles that deliver a therapeutic cargo directly to a disease site. This specific targeting could help avoid the nasty side effects that patients feel when a drug goes to heathy areas in the body. But barriers, such as blood vessel walls, can divert particles from reaching their intended destination. To get around such obstacles, scientists need a better understanding of how nanoparticles interact with structures inside the body. Current techniques, however, are limited. Warren C. W. Chan and colleagues from the University of Toronto  (Canada) wanted to develop a method to better track where nanoparticles go within tissues.

The researchers injected an acrylamide hydrogel into organs and tissues removed from mice. The gel linked all of the molecules together, except for the lipids, which are responsible for making tissues appear opaque. The lipids easily washed away, leaving the tissues clear but otherwise intact. Using this technique, the researchers could image nanoparticles at a depth of more than 1 millimeter, which is 25 times deeper than existing methods. In addition to helping scientists understand how nanoparticles interact with tumors and organs, the new approach could also contribute to tissue engineering, implant and biosensor applications, say the researchers.


Nanotechnology Fights Skin Disease

Researchers at The Hebrew University of Jerusalem have developed a nanotechnology-based delivery system containing a protective cellular pathway inducer that activates the body’s natural defense against free radicals efficiently, a development that could control a variety of skin pathologies and disorders. The human skin is constantly exposed to various pollutants, UV rays, radiation and other stressors that exist in our day-to-day environment. When they filter into the body they can create Reactive Oxygen Species (ROS) – oxygen molecules known as Free Radicals, which are able to damage and destroy cells, including lipids, proteins and DNA. In the skin – the largest organ of the body – an excess of ROS can lead to various skin conditions, including inflammatory diseases, pigmenting disorders, wrinkles and some types of skin cancer, and can also affect internal organs. This damage is known as Oxidative Stress. The body is naturally equipped with defense mechanisms to counter oxidative stress. It has anti-oxidants and, more importantly, anti-oxidant enzymes that attack the ROS before they cause damage.

In a review article published in the journal Cosmetics, a PhD student from The Hebrew University of Jerusalem, working in collaboration with researchers at the Technion – Israel Institute of Technology, suggested an innovative way to invigorate the body to produce antioxidant enzymes, while maintaining skin cell redox balance – a gentle equilibrium between Reactive Oxygen Species and their detoxification.

skin nano

The approach of using the body’s own defense system is very effective. We showed that activation of the body’s defense system with the aid of a unique delivery system is feasible, and may leverage dermal cure,” said Hebrew University researcher Maya Ben-Yehuda Greenwald.

She showed that applying nano-size droplets of microemulsion liquids containing a cellular protective pathway inducer into the skin activates the natural skin defense systems.

Currently, there are many scientific studies supporting the activation of the body’s defense mechanisms. However, none of these studies has demonstrated the use of a nanotechnology-based delivery system to do so,” adds Ben-Yehuda Greenwald.