One-pot synthesis of acid-induced in situ aggregating theranostic gold nanoparticles with enhanced retention in tumor cells

In this work, we took advantage of a one-pot reaction to prepare tumor-targeting nanoparticles (Au@T), which could respond to the intracellular acidic environment and form aggregates to enhance the retention effect of nanoparticles in tumor cells. Au@T is composed of gold nanoparticles (Au NPs) modified with 4-mercaptobenzoic acid (MCBA), p-hydroxythiophenol (HTP), LA (lipoic acid)-PEG2K-OCH3 and LA-PEG2K-biotin. During blood circulation, Au@T remains well dispersed, making it inconspicuous. Then, with the help of active targeted transport, much more Au@T becomes internalized at the tumor site. After being internalized by tumor cells, Au@T aggregates under the condition of pH = 6.0, thereby improving the retention effect of Au@T, stymieing exocytosis and reducing the amount of nanoparticles returned to the blood stream. Furthermore, the in vivo experimental results showed that aggregated Au@T exhibits excellent photothermal effects, with a tumor inhibition rate of 86.40%. The computed tomography (CT) value was found to be 1.5 times higher than that of the control group (Au@Bio), as Au@Bio was unable to aggregate in tumor cells. In conclusion, this work provides a simple method for synthesizing a type of gold nanoparticles (Au@T) with promising potential for tumor diagnosis and treatment through enhancing the retention effect in tumor cells.