Researchers are working on a series of nanomaterials that respond specifically to cancer, which can specifically provide imaging compounds to cancer cells for treatment, such as nanomaterials that are more sensitive to proteases.
According to an article published in the journal Science and Technology of Advanced Materials, nanosystems are making significant progress in providing anticancer drugs or imaging materials to tumors, especially for tumor-related stimuli React those nanomaterials. However, further research is needed to ensure the stability of these delivery systems and to ensure that they are non-toxic and biodegradable.
Nanocarriers designed to release their contents only in cancerous tissue are important because they not only reduce the negative effects of chemotherapeutic drugs on healthy tissues, they also provide contrast materials to tumors to enhance imaging.
Reviewers from Xiamen University in China explained that nanomaterials specifically target tumors by responding to unique tumor conditions such as acidity and excess enzymes.
Acidity levels often vary depending on the type of tissue, and tumors usually have a higher acidity than the healthy tissue around them. Researchers are using it to design vehicles for organic, inorganic, and hybrid nanomaterials that can release their contents in response to the acidic environment of tumors. For example, acid-sensitive polymers have been explored for the delivery of a chemotherapeutic drug doxorubicin coupled to a fluorescent compound. When the drug finds its target, it is absorbed by tumor cells and exposed to an acidic environment, and then the polymer changes shape by releasing its contents for the treatment and imaging of cancer cells.
Reduction potential is also used as a stimulus for cancer-targeted delivery vehicles, a measure of the tendency of molecules to acquire electrons so that the potential becomes "reduced." The reduction potential in cancer tissue is different from that in healthy tissue.
Nanocarriers designed as reducing agents are decomposed into a substance called reduced glutathione tripeptide when exposed in vivo, which is 1000 times higher inside tumor cells than outside. This type of nanocarrier has excellent stability in blood and responds quickly in the reducing environment of tumors. Some of these nanocarriers have been approved by the US Food and Drug Administration for use in clinics.
Other nanocarriers respond to abnormally expressed enzymes in tumors. These nanocarriers are made of materials that can be broken down by these enzymes, releasing the contents. In some cases, the breakdown of the nanocarrier wall is so effective that it can reduce the amount of drug needed to have a therapeutic effect.
Although these nanomaterials show promising prospects, much more needs to be done. For example, acid-responsive carriers need to have better drug-loading capabilities, stability, and biodegradability, and further inspection of the toxicity of enzyme-responsive materials is needed.
"Given the huge potential of stimulus-response nanomaterials, we should work even harder to create more trigger drug delivery platforms that increase efficiency and reduce the side effects of cancer treatment," the researchers concluded.