A nanoparticle imaging system capable of highlighting a broad range of tumour types in mice is reported in a study published online in Nature Materials this week.

Cancers exist in a variety of genotypes and phenotypes and, as a consequence, finding an imaging strategy that can be widely applied in cancer diagnostics is challenging. However, there are some common factors of the tumour microenvironment, such as elevated acidity and rapid blood vessel growth, that could be exploited for detection.

Jinming Gao and colleagues describe a series of ultra pH-sensitive fluorescent nanoparticles that can detect the acidity and developing vasculature within the microenvironment of tumours in a broad range of mouse cancer models. The nanoparticles cannot be seen while in circulation in the blood but light up when they reach the acidic environment or new blood vessels of the tumours. By incorporating different colour dyes, simultaneous monitoring of many different tumours is possible.

The researchers also show that their imaging strategy can detect tumours rapidly (within the first hour following intravenous injection) and can recognize very small tumours (～1 mm3), enabling the detection of responses directly following acute drug treatments.