METHOD FOR PREPARING HIGH-CONCENTRATION PENTA-TWINNED GOLD NANOPARTICLES

The present invention concerns a method for preparing penta-twinned gold nanoparticles comprising at least the following steps: i) providing a suspension of gold seeds comprising gold seeds, a cationic surfactant and at least one inert solvent, the temperature of the suspension being between 30 and 75°C; ii) providing a growth solution comprising a gold salt, a cationic surfactant, a reducing agent, the reducing agent being an aromatic compound comprising at least one aromatic ring carrying at least one hydroxyl group, and optionally at least one base; iii) subjecting the suspension of gold seeds from step i) to a growth treatment comprising the following steps: iii1) adding the growth solution from step ii) in a controlled manner to the suspension of gold seeds from step i); iii2) maintaining the temperature of the mixture obtained in step iii1) at a temperature of between 30°C and 75°C for at least 5 minutes. The invention also concerns a nanosuspension likely to be obtained according to the method of the invention, and the use of same for manufacturing an optical sensor.