PreS1 peptide-functionalized gold nanostructures with SERRS tags for efficient liver cancer cell targeting

Early detection is the most effective mean of improving prognosis for many fatal diseases such as cancer. In this context, the Surface Enhanced Resonance Raman Scattering (SEARS) technique is being proposed as alternative to fluorescent methods in detection of biomarkers, because SERRS nanostructures are bright as fluorescent tags but more stable and clearly detectable using the narrow Raman "fingerprints" of a suitable reporter. Here we show that biocompatible SERRS active gold nanostructures, functionalized with an engineered PreS1 peptide (AuNP@PEG-PreS1), detect the presence of the SerpinB3 antigen overexpressed on liver tumor cells, a biomarker of the onset of liver cell carcinomatous transformation. A proper engineering of the targeting unit, linked to the nanostructure by a polymer chain, affords a sensitivity and specificity larger than 80%, at subnanomolar concentrations. Taking into account the high sensitivity of SEARS and that SB3 overexpression is an early event in liver cell carcinomatous transformation, AuNP@PEG-PreS1 nanostructures could be used in routine diagnostic activities, to improve the accuracy of HCC detection in particular in patients with chronic liver diseases.