A New Way to Help Patients Undergoing Chemotherapy Treatment

Title: 3D Printed Absorber for Capturing Chemotherapy Drugs before They Spread through the Body

Authors: Hee Jeung Oh, Mariam S. Aboian, Michael Y. J. Yi, Jacqueline A. Maslyn, Whitney S. Loo, Xi Jiang, Dilworth Y. Parkinson, Mark W. Wilson, Terilyn Moore, Colin R. Yee, Gregory R. Robbins, Florian M. Barth, Joseph M. DeSimone, Steven W. Hetts, and Nitash P. Balsara

Journal: ACS Central Science

Year: 2019

Article: https://pubs.acs.org/doi/pdf/10.1021/acscentsci.8b00700

Chemotherapy is a common method used to treat cancer, but it must be broadly applied to the entire body and has many negative consequences for the patient.  Cancer is one of the leading causes of death in developed nations, so many people are required to undergo chemotherapy treatment. This treatment kills all fast-growing cells in the body, which includes hair, so patients always lose their hair, eyebrows, and eyelashes. There are many other side effects including fatigue, nausea, and lack of appetite. Since patients must undergo treatment for many weeks these effects are very impactful on their lives. The recent Chembite by Rebekah discusses one possible solution using targeted drug delivery, but these researchers are exploring another option: using drug capture to prevent the spread of the excess drug around the body.

The researchers 3D printed porous cylinders to create a drug absorber (Figure 1). These cylinders had a central hole for attachment into a vein during surgery, surrounded by a square lattice. The lattice structure was then coated in a polymer that has been shown to bind the chemotherapy drug. The researchers tested it with the most common chemotherapy drug, doxorubicin (Figure 2). The drug is typically administered by IV, and with their absorber, the drug would be injected before the cancerous tumor, and the absorber would be placed directly after the tumor to prevent the spread of the drug to the whole body.

Figure 1: (a) cartoon of the entire cylinder (b) inner view of cylinder (c) chemical reaction occurring inside the 3D printer (d) chemical structure of the polymer used to coat the cylinder for absorption of chemotherapy drug (e) scaffold before coating in polymer (f) cylinder after coating in polymer (g) view from above of lattice structure after coated (h) cross section of lattice after coating with polymer.
Figure 2: Chemical structure of doxorubicin, a common chemotherapy drug.

To test the absorbers, the researchers implanted their devices in pigs that then received an infusion of the chemo drug to treat a tumor in the liver. They measured the concentrations of the drug before and after the implanted absorber, and elsewhere in the body far away from the location of the drug dosage. This allowed researchers to see how much drug was removed by the absorber directly after the absorber and if this then reduced levels of the drug in other areas of the body. This can be seen schematically in Figure 3a and imaged in the animal in Figure 3b,c.

Figure 3: (a) cartoon of the implementation of the absorber. Drug is delivered at (1), the pre-device drug levels are tested at (2) and the post-device levels are tested at (3). (b) Image of the device in the vein (c) magnified image of the device in the vein showing the absorber.

The researchers performed one test with control absorbers, which do not have any polymer coating, and another with the drug-capturing polymer coating. The coated absorber captured 69% of the drug that would have otherwise been spread through the body (Figure 4).  There was also a slight reduction in the drug amounts in other peripheral areas of the body, which would reduce the impact of the drug on other organs.

Figure 4: (a) Trace of the drug concentration over time with uncoated cylinders. Black shows the pre-device levels, red shows the post-device levels, and blue shows the levels elsewhere in the body. (b) Trace of drug concentrations with coated cylinders. Colors are the same as in (a). The difference in concentration can be seen by comparing the red trace in (a) and (b) where significantly more drug has been absorbed by the coated absorbers.

The researchers also tested if the drug could escape from the absorbers by pumping a solution of potassium chloride and ethanol over the absorbers for one month, but there was a negligible amount of drug released. The drug is permanently bound to the polymer, so the drug would likely not be released back into the body when the absorber is removed.

These scientists have developed a new method of absorbing excess drug delivered to treat a tumor. This is highly valuable in treating cancer, where extremely toxic drugs are used in high concentrations to kill cancerous cells but have the painful side effects of killing healthy cells. Implementation of these absorbers could greatly help us improve patient health and mitigate the damage of cancer treatment.

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