Diagnostic nanoparticles "six in one"
One nanoparticle – six research methods
Ekaterina Baranova, sci-lib based on Nanotechweb – One nanoparticle: six imaging modalitiesAccording to the recently published work of an international group of scientists, a new type of nanoparticles potentially allows to examine the body of patients in six different ways, while introducing only one contrast agent.
If the technology is refined before the transition to clinical practice, it will allow doctors to combine the strengths of a number of imaging techniques, providing a clear picture of the patient's organs.
The nanoparticles proposed by scientists from the University of Buffalo (USA), University of Pennsylvania (USA) and their colleagues from Harbin Institute of Technology (China) have an average diameter of 74 nm. Each of them consists of two parts: nuclei and shells of porphyrin-phospholipid. The components of nanoparticles have their own properties that contribute to visualization in various modes.
The main component, originally developed for photonic up-conversion, fluoresces blue when irradiated with light in the near infrared range, which potentially makes it possible to visualize deeply located objects. In addition, the core containing ytterbium makes it possible to carry out CT imaging. The outer shell of nanoparticles has biophotonic properties, which makes them suitable for use in fluorescent and photoacoustic imaging techniques. Also, the affinity of the porphyrin shell with copper makes it possible to easily cover nanoparticles with radioactive copper-64 for use in the framework of luminescent display techniques.
Diagram from an article in Advanced Materials – VM
The researchers conducted an initial test of the proposed nanoparticles in a test tube, and then used the resulting contrast to visualize the internal structure of the turkey fillet (to determine the attenuation of the signal depending on the depth of its penetration). Turkey fillet was chosen as a medium similar in structure to human breast tissue (the display of lymph nodes is currently a primary task in the detection of breast cancer). Subsequently, nanoparticles were used to map the lymph nodes of live mice. This experiment demonstrated the huge potential of an integrated approach to research: photoacoustic tomography provides information about blood vessels, while CT provides data on the local structure of bone tissue. Combining the techniques allows you to simultaneously obtain information about deeply located tissues and about the absorption of nanoparticles by cells. As the scientists themselves note, an additional advantage of visualization using nanoparticles consisting of a nucleus and a shell is the ability to obtain data at various scales, from single molecules to whole living cells and organs of the body.
It is worth noting that with all the variety of research techniques available with such a contrast, the proposed nanoparticles are not expensive and easy to manufacture (compared to other contrast agents). Unfortunately, an aggregate capable of receiving all six variants of images simultaneously does not exist at the moment. However, the researchers hope that in the near future a toolkit will be developed that can use at least part of the potential of nanoparticles, since work in this direction has been underway for quite a long time. Integration of even several separate visualization tools in a single package may already be suitable for clinical use. However, before switching to the use of these nanoparticles in the framework of human body research, it will be necessary to test them for safety.
In addition to the aforementioned testing of nanoparticles, the scientific group plans to look for other applications for the developed nanostructures in the near future. One of the possible directions is an attempt to add another molecule to the surface of nanoparticles, which will ensure the accumulation of particles in cancer cells and a clearer display of tumors.
Detailed results of the work are published in the journal Advanced Materials (Rieffel et al., Hexamodal Imaging with Porphyrin-Phospholipid-Coated Upconversion Nanoparticles – VM).
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