'Failed drug molecules may be reused as semiconductors'

The study, published in the journal Nature Communications, noted that biological molecules once considered for cancer treatment can now be redesigned as organic semiconductors for use in chemical sensors and transistors.

The researchers, including those from the University of Illinois in the US, looked at a well-studied class of bioactive molecules called DNA topoisomerase inhibitors which prevented the genetic material from replicating, and was once explored as a potential anti-cancer agent.

"While examining these pharmaceutical molecules, we noticed that their molecular structures looked much like the organic semiconductors we were working with in the rest of my group," said co-author and biomolecular engineering professor Ying Diao of the University of Illinois.

The study noted that the DNA topoisomerase inhibitors were flat and contained neatly stacked columns of electrically conductive molecular rings, which according to the researchers were features of a good semiconductor.

The researchers said that these molecular columns are linked together by hydrogen bonds that are capable of moving charges from column to column, and forming bridges which transform the entire molecular assembly into a semiconductor.

According to Diao, these molecules can interact with biological material with high specificity, making them suitable candidates to be made into biosensors.

"They are also easily printable but will require new solvents because they are chemically different than other organic semiconductors. The fabrication infrastructure is already in place," Diao said.

The researchers said that the efficiency and performance of the semiconductors made from these drugs need improvement.

But Diao added that the real excitement regarding this advance comes from the possibility of discovering similar molecules.