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To produce the hairy cellulose nanocrystals capable of capturing chemotherapy drugs, the researchers chemically treated cellulose fibres found in softwood pulp and imparted a negative charge on the hairs, making them stable against the charged molecules found in the blood. This corrected the problems found with conventional nanoparticles, whose charge can be rendered inert or reduced when exposed to blood, limiting the number of positively charged drug molecules it can bind to in insignificant numbers.

The nanocrystals' binding efficacy was tested in human serum, the protein-rich liquid portion of blood. For every gram of hairy cellulose nanocrystals, more than 6,000 milligrams of DOX were effectively removed from the serum. This represented an increase in DOX capture of two to three orders of magnitude compared to other methods currently available.

Furthermore, DOX capture occurred immediately after the addition of the nanocrystals and the nanocrystals had no toxic or harmful effects on red blood cells in whole blood or on cell growth of human umbilical cells.

Such a powerful means of drug capture within the body can have a great impact on cancer treatment regimens, as doses can be elevated to more effective levels without the worry of detrimental side effects.

Principal investigator, Amir Sheikhi, assistant professor of chemical engineering and biomedical engineering at Penn State, offered an example of such an application, "For some organs, like the liver, chemotherapy can be locally administered through catheters. If we could place a device based on the nanocrystals to capture the excess drugs exiting the liver's inferior vena cava, a major blood vessel, clinicians could potentially administer higher doses of chemotherapy to kill cancer more quickly without worrying about damaging healthy cells. Once the treatment is finished, the device could be removed."

In addition to removing excess chemotherapeutic drugs from the body, the hairy cellulose nanocrystals could also target other undesirable substances such as toxins and addictive drugs for removal from the body, and experiments have also demonstrated the nanocrystals' effectiveness in other separation applications, such as in the retrieval of valuable elements from electronic waste.

"What began as a relatively simple concept has evolved into a highly effective means of materials separation," said Ali Khademhosseini, director and CEO at the Terasaki Institute for Biomedical Innovation.

"This creates the potential for wide-ranging and impactful biomedical and materials science applications," he added.

Additional authors are Sarah AE Young, Joy Muthami, Mica Pitcher, Petar Antovski, Patricia Wamea, Robert Denis Murphy, Reihaneh Haghniaz, Andrew Schmidt and Samuel Clark.

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