Hybrid-Free DNA Test by Band Engineering of Nitride Semiconductor and Machine Learning

Deoxyribonucleic acid (DNA) testing is a key step in personalized medical treatments. The technique often involves hybridization between complementary single DNA strands to identify the target gene. However, the formation of a hybrid DNA is slow. To capture the target quickly, we present a label-free hybrid-free DNA detection by surface-enhanced Raman spectroscopy (SERS), whose performances are boosted by InGaN quantum wells (QWs) and machine learning. This is realized by tuning the energy states of QWs, within which the confined electrons resonate with those vibrating on the oligonucleotide and the roughened aluminum (Al) surface. The QW-Al-DNA resonance promotes many minor SERS signals to the detectable level, allowing the machine to identify four distinct circulating tumor DNAs responsible for pancreatic, thyroid, lung, and breast cancers in 1 h.