Engineering an “Invisible Cloak” for Bacteria to Deliver Cancer Drugs

Scientists exploring a novel but highly promising avenue of cancer treatment have developed a type of “invisibility cloak” that helps engineered bacteria sneak through the body’s immune defenses. The result is more powerful delivery of anti-cancer drugs and shrinking of tumors in mice, with the scientists hopeful the approach can overcome toxicity issues that have plagued these techniques so far.

Traditional forms of cancer treatment – radiotherapy, chemotherapy and immunotherapy – each have their own strengths when it comes to combating tumors, and what’s known as therapeutic bacteria could bring its own set of skills into the mix. Bacteria itself can have powerful anti-tumor effects, but genetic engineering could allow it to take on entirely new capabilities, including releasing specific compounds or carrying potent anti-cancer drugs. There are a number of challenges in using bacteria for this purpose, however, with the issue of toxicity chief among them. Living bacteria can grow rapidly in the body, and because the body’s immune system sees them as a threat, too many can trigger an extreme inflammatory response.

In clinical trials, these toxicities have been shown to be the critical problem, limiting the amount we can dose bacteria and compromising efficacy,” said Columbia University‘s Jaeseung Hahn, who co-led the research. “Some trials had to be terminated due to severe toxicity.

Addressing this toxicity problem would mean finding (or engineering) bacteria that can evade the body’s immune system and safely make it to a tumor to fulfill their anti-cancer potential. Hahn’s team has made new inroads in this space by turning to sugar polymers called capsular polysaccharides (CAP), which naturally coat bacterial surfaces and protect them from immune attacks.

We hijacked the CAP system of a probiotic E. coli strain Nissle 1917,” said Tetsuhiro Harimoto, the study’s co-lead author. “With CAP, these bacteria can temporarily evade immune attack; without CAP, they lose their encapsulation protection and can be cleared out in the body. So we decided to try to build an effective on/off switch.”

Source: https://www.engineering.columbia.edu/

Lead-Free Perovskites Boost Generation Of Electric Current

Lead-based perovskites are quite promising in applications of large-scale photovoltaic technology. However, toxicity is one of the crucial issues in these materials.

In the search for Lead-free perovskite, UNIST scientists have taken a major step forward toward a new generation of solar cells. They have developed new perovskite material that works as a charge regenerator with dye‐sensitized solar cells and have higher efficiency and stability.

Scientists used the vacancy‐ordered double perovskite (Cs2SnI6). They primarily examined the charge transfer mechanism of Cs2SnI6 with the aim of clarifying the function of its surface state.

For this reason, a 3‐electrode system was produced to observe charge exchange through the surface state of Cs2SnI6.  “Due to a high volume of electrical charges in organic dyes that show high connectivity with the surface state of Cs2SnI6, more electric current was generated,” said Byung-Man Kim from the Department of Chemistry at UNIST. “Consequently, Cs2SnI6 shows efficient charge transfer with a thermodynamically favorable charge acceptor level, achieving a 79% enhancement in the photocurrent density compared with that of a conventional liquid electrolyte.”

Source: http://news.unist.ac.kr/