Lanthanide (Ln<sup>3+</sup>)-doped nanoparticles (NPs) have shown great promise in versatile bioassay. We constructed a supramolecular sensor array by hybridized time-resolved Förster resonance energy transfer (TR-FRET) with the indicator displacement assay (IDA) concept. The sensor array was generated by binding a series of negatively charged indicators on the surface of NaYF<sub>4:</sub>Ce/Tb NPs. The sensor array could successfully discriminate 6 model proteins with high accuracy and sensitivity both qualitatively and quantitatively.
We report the synthesis and characterization of arginine-glycine-aspartic acid (RGD) peptide-targeted polyethylenimine (PEI)-entrapped gold nanoparticles (RGD-Au PENPs) for targeted CT imaging of hepatic carcinomas in situ. In this work, PEI sequentially modified with polyethylene glycol (PEG), and RGD linked-PEG was used as a nanoplatform to prepare AuNPs, followed by complete acetylation of PEI surface amines. We showed that the designed RGD-Au PENPs were colloidally stable and biocompatible in the given concentration range, and could be specifically taken up by α<sub>v</sub>β<sub>3</sub> integrin-overexpressing liver cancer cells in vitro. Furthermore, in vivo CT imaging results revealed that the particles displayed a great contrast enhancement of hepatic carcinomas region, and could target to hepatic carcinomas region in situ. With the proven biodistribution and histological examinations in vivo, the synthesized RGD-Au PENPs show a great formulation to be used as a contrast agent for targeted CT imaging of different αvβ3 integrin receptoroverexpressing tumors.