Multifunctional nanomedicine holds considerable promise as the next generation of medicine that will enable early detection of diseases, as well as simultaneous monitoring and
therapy with minimal toxicity. In particular, surface-enhanced Raman scattering (SERS) technology with high sensitivity and multiplexing capabilities is emerging as a powerful alternative for identifying specific
biological targets in live cells. In this paper, we present the synthesis of SERS-active
gold nanochains (AuNCs) as a potential
theranostic system for multiplex detection and
photodynamic therapy (
PDT) of
cancer. AuNCs were prepared by a simple physical mixing method to assemble
citrate-stabilized
gold nanoparticles into nanochains using
hyaluronic acid and hydrocaffeic
acid (HA-HCA) conjugates as templates. In addition, Raman reporters and
photosensitizers (PSs) were conjugated onto the surface of the AuNCs for multiplex detection and
PDT action. After mixing with HA-HCA conjugates,
citrate-stabilized
gold nanoparticles formed the AuNC structure, and AuNC length was controlled by the HCA conjugation ratio in the HA-HCA conjugates. AuNCs exhibited maximal absorption in the near-infrared (NIR) spectral region and effective SERS property. Confocal microscopy, flow cytometry, Raman spectroscopy and Bio-TEM measurements were used to determine cellular uptake of the Raman reporter, PS and AuNCs in HeLa cells. AuNCs conjugated with Raman reporter and PS (HA-HCAn-Au-Pheo-NPT) showed more than 99% cellular uptake and exhibited excellent
phototoxicity even at low PS concentrations compared with free PS after
laser irradiation. This SERS-active AuNC (HA-HCAn-Au-Pheo-NPT) shows promise for applications in
theranostics, integrating SERS imaging and
PDT.