Science or Pseudoscience: Ancient Chinese Calligraphy Ink and Cancer Treatment

When it comes to reading about cancer cures in the media it is usually good advice to be pretty skeptical. Sometimes the story lends well to skepticism – like this one recently covered in a few outlets where it was proclaimed that scientists had found a cure for cancer in ancient Chinese calligraphy ink. It’s a story that has everything – including lasers. Here is a romantic idea that the cure for cancer might lie in an ink that is produced from plants and has been handed down between generations as a way to share writing and art. The proposed treatment is billed as non-invasive and specific only for cancer cells – could this really be science?

I was particularly suspicious when I saw that the representation of the story on Natural News, a prominent proponent of pseudoscience, looked a lot like the story on Science Alert which is typically more of a reliable source on science stories. So I did some digging into the data for this finding.

The paper that was covered in the media is titled “New Application of Old Material: Chinese Traditional Ink for Photothermal Therapy of Metastatic Lymph Nodes” and was published in the journal ACS Omega in August 2017. The researchers were based in Shanghai distributed across various institutes at different hospitals or universities. They had been working on a relatively new cancer therapy called Photo-thermal Therapy (PTT).

Photo-thermal therapy (PTT)

In cancer treatment, PTT is the use of specific types of nanoparticles to generate cell damaging heat specifically at the tumour sites. Scientists take a material that can be stimulated with light – typically infra-red – causing the generation of heat and subsequent tumour cell death. The problem is that many of these nanoparticles are toxic or expensive so in order to make the treatment as efficient and effective as possible, we need to find just the right material.


Hu-Kaiwen (Hu-ink) is an ink that has been used by calligraphers in China for hundreds of years. It’s derived from plants, is mostly made up of carbon and it is black in colour which the materials used for PTT tend to be. So scientists got to wondering if it might be useful for PTT.

Firstly the authors of this study looked at the stability of the ink. They diluted it in different things including water and saline and made sure it was stable when stored over time. They looked at the structure of the ink and noticed that it typically forms small aggregates of 20-50nm in diameter – nanoparticles. They confirmed that the core component of the ink was carbon and they stimulated different concentrations of the diluted ink with infra-red lasers and tested the temperature. They found that Hu-ink was more efficient at converting light into heat than most other PTT materials reaching temperatures of 55°C after five minutes irradiation.

Hu-ink for PTT in cancer cells grown in the lab

In research we use cell models of cancer which we refer to as cancer cell lines. These are cells that have originally been taken from patients with different types of cancer but are grown and stored artificially in the lab. We use them so we can test things out on cells that behave like cancer but aren’t in a human body before we move on to doing tests in living organisms. The researchers in this study used some cancer cells originally derived from colon (SW-620) and colorectal (HCT-116) cancer. First they treated the cells with just the Hu-ink and the cells tolerated it really well proving that the ink solution itself wasn’t toxic. Then they treated the cells with the ink and combined it with irradiation with the infra-red laser.

HCT-116 cells treated with Hu-ink and infra-red compared to HCT-116 cells treated with infra-red only. Image modified from the paper.

The image above is part of a figure taken from the paper itself. There are three images of HCT-116 colorectal cancer cells. In the top image, the cells were treated with only the laser for five minutes. They were not given any Hu-ink. In the middle image the cells were treated both with the Hu-ink at a medium dose for two hours and the laser for five minutes. In the bottom image the cells received a high dose of the Hu-ink for two hours and the laser for five minutes. The red cells are cells stained with a marker of cell death. The green cells are living cells. You can also see that the dead cells are much smaller than the living cells. In the top image where cells did not receive any ink – all of the cells are alive. In the bottom image where the cells had a high dose of ink – all of the cells are dead. In the middle image with a lower dose of the ink, there are some living cells and some dead cells. In other words – when you treat cancer cells with both Hu-ink and infra-red, the cancer cells die.

Hu-ink for PTT in mice

The researchers wanted to be sure that this technique was safe in living organisms and that it was able to kill cancer cells in living organisms. So they took mice with cancer of the lymph nodes and injected Hu-ink into the tumour which they then irradiated with infra-red. After an allocated treatment time, they removed the tumours from the mice and measured them.

Lymph node tumours taken from mice treated with Hu-ink and infra-red versus control treatments. Image modified from the paper.

For this experiment they had three control conditions – NS (the tumours were injected with saline), NS plus laser (the tumours were injected with saline and treated with a laser) and Hu-ink (the cells were injected with Hu-ink). They had one test condition – the Hu-ink plus laser. The test condition is the only one that the authors predicted would have an effect on tumour size. And that’s exactly what they saw. Lymph node tumours treated with Hu-ink and infra-red were significantly smaller than the control conditions. They also saw that the surrounding tissue wasn’t damaged suggesting that the treatment is safe.

Study conclusion

This study is a proof-of-principle study. The authors have shown that this ink can be used in PTT therapy with a positive effect and in a safe way in mice and in the lab. It is a very small scale study and it is a single study. It needs replicating before we can be confident in the result and it needs to be studied on a larger scale and have many more safety tests before we could begin to think about using it in patients. But it is a really promising study. It takes a treatment we already use and aims to make that treatment safer and cheaper and more available to patients. It is a non-invasive treatment and it can be used in ways that reduces tissue damage to healthy tissue while targeting cancer cells for cell death. It’s a great example of some really cool science, using materials that have been available for many years and applying them to modern techniques.

It might seem far-fetched to say ancient ink can help us treat cancer, but really it’s just cool science!

Author: Dr Alice Howarth

I am a science loving PhD cancer researcher with a passion for science accessibility. I like cell biology, scientific skepticism and equality. For almost 5 years I have been an integral part of The Merseyside Skeptics society - a non-profit organisation which aims to promote scientific reasoning, nationally and internationally. I am co-host of the successful podcast, Skeptics with a K where I discuss topical science stories on a fortnightly basis. I am a science communicator to a wide variety of audiences from school age children to interested members of the public and academic researchers.

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