COOH-Terminated Silicon Quantum Dots as a Highly Efficient Drug Nanocarrier for Targeted Tumor Cell Imaging

Fluorescent silicon quantum dots (SiQDs) characterized by exceptional photostability and colloidal robustness as well as beneficial biocompatibility are fast becoming new pharmaceutical nanocarriers. With a view to efficiently loading cisplatin (CDDP) onto SiQDs, carboxylate group (COOH) terminated SiQDs were imperative because of chelate formation with CDDP. In this work, we employed a facial microwave irradiation route for rapidly synthesizing high-quality COOH-SiQDs through the use of 3-aminopropyl trimethoxy silane (APTMS) molecules to fulfil the role of silicon precursor and maleic acid (MA) as the agent for facilitating reduction. The SiQDs showed blue fluorescence with an associated photoluminescence quantum yield (PLQY) of 40.2%, the size of which was small at 3.2 ±0.6 nm, and long-lasting stability (an extensive range in pH (4-12) and concentrations of electrolytes reaching 3 Molarity of a solution of sodium chloride). As nanocarriers, carboxylic acids chelation generated a high loading of CDDP onto SiQDs (drug loading capacity, DLC up to 32.2% at pH = 9) and a drug release of CDDP up to 57.6% at pH = 5. Furthermore, the MTT assays demonstrated the non or low cytotoxicity of SiQDs and the role of the controlled release of SiQD-CDDP Finally, the prepared SiQD-CDDP were used for cell imaging, and further targeted labeling of some tumors after folic acid (FA) conjugation. These characteristics allow for the deployment of SiQDs as a highly efficient nanocarrier that facilitate the delivery of clinical drugs for the future.