Powerful Particles: An Innovative Approach to Cure Cancer

The majority of people in the world have known someone with cancer. It is a difficult time. The need for new cancer treatments is evident, and the newest breakthrough in the fight against cancer is nanoparticles, dendrimers and aptamers, used to deliver anticancer drugs.

                                                                                                                        The problem with most cancer-fighting drugs is that drugs that are powerful enough to kill cancer cells also kill healthy cells. Nanoparticles can deliver drugs directly to a cancerous site. That is why they are so important to cancer treatment. Typically, nanoparticles used for cancer treatment are called dendrimers, which can be combined with aptamers. A dendrimer, sometimes called a cascade molecule, is a polymer that has many branches that move out from a carbon core (Definition of Dendrimer, 2000). Functional groups at the ends of the dendrimers make cancer treatment possible. Discovered in the 1980’s, they are man-made in laboratories (Bryszewska & Klajnert, 2001). Aptamers are nucleic acid ligands, nucleic acids which bind to larger molecules. In the case of cancer treatment, these are parts of DNA or RNA that attach to antigens as the larger molecule with high accuracy. Aptamers are still in their early stages of helping with cancer treatment, so any idea of their use is just developing, and is not widespread. The basis of nanoparticle cancer treatment is that dendrimers, which can be combined with aptamers to make nanoparticle-aptamer bioconjugates (Mason, 2005), are released in the blood stream. The dendrimers are no larger than one ten-thousandth of a millimeter in diameter, which means that dendrimers can only leave the blood stream at the liver and the cancer site. If aptamers are involved, they help the nanoparticles reach the cancerous cells. Scientists have engineered the dendrimers to be attracted to water, which limits how many dendrimers can leave the blood stream through the liver (Nanoparticles could carry cancer drugs, 2003). Once they reach the cancerous site, the dendrimers offer a controlled release of the medicine. If aptamers are involved, then they lead the nanoparticle to the cancerous site.

            It had been observed that exposure to high concentrations of dendrimers could be dangerous. Dendrimers typically have an electric charge, and so they are attracted to cell membranes of healthy cells, too. This destroys healthy cells. That is why scientists from the University of Michigan manipulated dendrimers to give them no charge (Delivering a knockout punch with smart drugs, 2005). The success of this experiment brought hope to those using dendrimers for cancer treatment.

                                                                                                                        Research in this field has flourished recently. Scientists from all over the world have been developing various nanoparticles for use in cancer treatment. One area of study has been developing more efficient nanoparticles. This includes developing nanoparticles of new materials and even new shapes. For instance, Zhiping Zhang led a team from the University of Singapore that helped develop “nanoparticles of poly(lactide)/vitamin E TPGS copolymer” (Zhang & Feng, 2006). Essentially, they developed a new nanoparticle. They found that there was 89% drug encapsulation efficiency for their nanoparticles that were 5% loaded with drugs (Zhang & Feng., 2006, p. 1-2). As far as shape goes, another team made up of scientists from the Nanyang Technological University, the Hong Kong Polytechnic University, and the National Institute of Education, Singapore, led by Pan Jie, researched the use of “Micelle-like nanoparticles of star-branched PEO-PLA copolymers as chemotherapeutic carrier” (Freddy, Huat, Min, Pan, & Venkatraman, 2005, p. 1). In their experiment they compared the success of star-branched copolymers (a type of nanoparticle that resembles a star) to that of linear copolymers (another type of nanoparticle) as used in chemotherapy. They used the cancer treatment drugs 5-FU and paclitaxel. Their results showed that the star-branched copolymers were an efficient nanoparticle for cancer treatment. It was observed that star-branched nanoparticles had similar drug content and entrapment efficiency to linear nanoparticles (Freddy et al., 2005, p. 2).

            Other experiments involved the efficiency of nanoparticles. One experiment by a team from the University of Singapore led by L. Mu. tested the efficiency of various nanoparticles of biodegradable copolymers in the release of paclitaxel, because other releases of paclitaxel involve harmful adjuvants (to aid in the drug’s delivery) such as Cremophor EL. Nanoparticles would eliminate the need for need for adjuvants. The team found that a 100% drug uptake efficiency could be achieved (Feng & Mu, 2003). Also, a team from Brazil led by Carolina Azevedo studied the “…uptake by the tumor of a cholesterol-rich microemulsion (LDE) associated to etoposide oleate in patients with ovarian carcinoma” (Azevedo, Carvalho, Maranhao, & Valduga, 2005, p. 1). It was found that LDE (a nanoparticle) was an efficient nanoparticle for ovarian cancer and could be used to administer etoposide oleate, a cancer fighting drug, to cancerous cells (Azevedo et al., 2005).

            From this short explanation of some current research, it is obvious that scientists are studying this topic from many angles, such as the particular kinds of nanoparticles, the shapes of nanoparticles, and the uptake by a tumor of anticancer drugs.

                                                                                                                        Much research is taking place in this field, and we can only learn more. Scientists are hoping to get nanoparticles to have more functions, such as reporting back on cell death. The most important innovation in this field has been the development of the nanoparticle-aptamer bioconjugates because they showed a tendency to target tumors. What this means for the patient is that they can eliminate cancer without killing many of their own cells. This is the true greatness of nanoparticles. Also, less of the patient’s healthy cells are killed. However, the nanoparticles must become more efficient drug carriers. The use of nanoparticles for cancer treatment is only in the experimental stage. The more efficient and practical these nanoparticles become, the more lives can be saved, and that has profound meaning for humanity. I have known people who have struggled with cancer, and I hope that advancements such as this will keep loved ones alive.