Polydopamine-based functional composite particles for tumor cell targeting and dual-mode cellular imaging

Particles which bear tumor cell targeting and multimode imaging capabilities are promising in tumor diagnosis and cancer therapy. A simple and versatile method to fabricate gold/polydopamine-Methylene Blue@Bovine Serum Albumin–glutaraldehyde–Transferrin composite particles (Au/PDA-MB@BSA-GA-Tf NPs) for tumor cell targeting and fluorescence (FL) / surface-enhanced Raman scattering (SERS) dual-modal imaging were reported in this work. Polydopamine (PDA) spheres played an important role in gold ion reduction, gold nanoparticle (Au NPs) binding and methylene blue (MB) adsorption, MB were employed as both fluorescence label and Raman reporter. In addition, glutaraldehyde (GA) crosslinked bovine serum albumin (BSA) in the outer layer of Au/PDA-MB nanoparticles can prevent MB from dissociation and leakage. The composite nanoparticles were further conjugated with transferrin (Tf) to target transferrin receptor (TfR)-overexpressed cancer cells. The targeting ability as well as the intracellular location of the probe was investigated through SERS mapping and fluorescence imaging. Their excellent biocompatibility was demonstrated by low cytotoxicity against breast cancer cell (4T1 cell). [Display omitted] •Tumor cell targeting Au/PDA-MB NPs composite particles with fluorescence and SERS activity was developed by a simple method.•Polydopamine (PDA) spheres serve as active template, AuNPs binding agent, gold ion reducing agent and methylene blue (MB) adsorption agent.•MB molecules as both fluorescence label and Raman reporter were loaded on Au/PDA NPs via electrostatic interaction and π-π stacking.•Biocompatible, excellent stability in physiological conditions and cell targeting, dual-mode imaging capability were confirmed.