New cancer-hunting “nano-robots” to search for and destroy tumors

It looks like a scene from a science fiction novel – an army of tiny armed robots traveling around a human body, hunting down malignant tumors and destroying them from within.

But research in Nature Communications today from the Davis Cancer Center at the University of California shows that the prospect of a realistic scenario may not be far off. Promising progress is being made in the development of a versatile anti-tumor nanoparticle called a “nanoporphyrin” that can help diagnose and treat cancers.

Cancer is the biggest killer in the world. In 2012, about 14.1 million new cases of cancer were diagnosed and about 8.2 million people died of cancer around the world.

This year cancer overtaken cardiovascular disease become the leading cause of death in Australia; 40,000 Australians died from cancer last year. It’s no wonder that scientists are exploring all possible technologies to diagnose and treat the disease effectively and safely.

Nanotechnology is one of these revolutionary cancer fighting technologies.

Nanotech: a big deal

A nanometer is a very small unit of length, barely a billionth of a meter. Nanotechnology seeks to create incredibly tiny structures at the nanoscale level for different functions and applications.

What is the real size of a nanoparticle?

One of these nanoparticle-based applications is the development of precise cancer diagnostic technology and the safe and effective treatment of tumors. The only problem is that nanoparticles have to be tailored for specific jobs. They can be time consuming and expensive to research and build.

So how do nanoparticles work? They can be made from inorganic or organic components. Each has different properties:

  • Inorganic nanoparticles often have unique properties that make them useful in applications such as fluorescence probes and magnetic resonance imaging tumor diagnostics;
  • “Soft” organic nanoparticles are the best drug delivery vehicles for the treatment of tumors, due to their biocompatibility, their ability to be chemically modified, and their drug load capacity. Some “soft” organic nanomedicines, including Genexol-PM (polymeric micelles loaded with paclitaxel), Doxil (liposomal doxorubicin) and Abraxane (human serum albumin nano-aggregate loaded with paclitaxel) have been approved or are in progress. clinical trials for the treatment of human cancers.

The new organic nanoparticle – nanoporphyrin – can do it all.

The ins and outs of nanoporphyrin

Nanoporphyrin is only 20 to 30 nanometers. If you want to get technical, this is a self-assembled micelle made up of crosslinkable amphiphilic dendrimer molecules containing four porphyrins.

Structure of porphin, the simplest porphyrin.
Wikimedia Commons

If you want to be less technical, this is a group of loosely bound molecules (or “micelles”) with their hydrophilic (“water-loving”) heads facing outward and their hydrophobic (“hate-hating”) tails. water ”) directed inwards. Each molecule contains organic compounds called porphyrins. Porphyrins can occur naturally, the best known being heme, the pigment in red blood cells.

The small size of nanoporphyrin gives it an intrinsic advantage as it can be engulfed and accumulate in tumor cells, where it can act on two levels:

  1. At the molecular level, nanoporphyrin may aid in diagnosis by enhancing contrast in tumor tissue using magnetic resonance imaging (MRI), positron emission tomography (PET), and bimodal PET-MRI. (Again, it’s a bit technical, but if you’re interested, porphyrin acts as a ligand, which chelates with imaging agent metal ions such as gadolinium (III) or copper (II). .)
  2. at the micelle level, nanoporphyrin can be loaded with anti-tumor drugs to kill malignant tissue. When activated, for example, it can generate heat to “cook” tumor tissue and release lethal reactive oxygen species (ROS) at tumor sites.

Armed and dangerous (for tumors)

The functional processes of nanoparticles can be similar to those of an armed nano-robot. For example, when a tumor recognition module is installed in a delivery nano-robot (organic particle), the drug-loaded armed nano-robot particles can target and deliver the drug into tumor tissue. They only kill these cells, while being harmless to surrounding cells and healthy tissue.

If a tumor recognition module is installed in a probe nanobot (inorganic particle), particles from the armed nanobot can penetrate tumor tissue and activate a measurable signal to help doctors better diagnose tumors.

It has been a huge challenge to integrate these functions on a single nanoparticle. It is difficult to combine imaging functions and light absorption capacity for phototherapy in organic nanoparticles as drug carriers. This has so far hampered the development of intelligent and versatile “all-in-one” organic nanoparticles for tumor diagnosis and treatment.

The production of nanoporphyrin is an effective strategy in the development of multifunctional and integrated nanoparticles. The same strategy could be used to guide other versatile nanoparticle platforms to lower nanomedicine costs, develop personalized treatment plans, and produce self-report nanomedicines.

Mavis R. Bernier