Alexandra Bondarenko

Monitoring Tyrosinase Expression in Non-metastatic and Metastatic Melanoma Tissues by Scanning Electrochemical Microscopy

Although tremendous progress has been made in the diagnosis of melanoma, the identification of different stages of malignancy in a reliable way remains challenging. Current strategies rely on optical monitoring of the concentration and spatial distribution of specific biomarkers. State-of-the-art optical methods can be affected by background-color interference and autofluorescence. We overcame these shortcomings by employing scanning electrochemical microscopy (SECM) to map the prognostic indicator tyrosinase (TyR) in non-metastatic and metastatic melanoma tissues by using soft-stylus microelectrodes. Electrochemical readout of the TyR distribution was enabled by adapting an immunochemical method. SECM can overcome the limitations of optical methods and opens unprecedented possibilities for improved diagnosis and understanding of the spatial distribution of TyR in different melanoma stages.

Electrostatic Spray Ionization Mass Spectrometry Imaging

Imaging samples on a surface by mass spectrometry (MS) requires the combination of MS detection with a scanning mode that enables localized desorption and ionization and/or detection of sample analytes with good spatial resolution. We have developed a new mass spectrometry imaging (MSI) method based on electrostatic spray ionization. It works under ambient conditions and can be applied to a wide range of molecules providing quantitative MS analysis even in the presence of salts in excess. 2D MS images of protein and peptide spots, inkjet-printed black dye patterns, and cells were obtained. The presented novel ambient ionization mass spectrometry imaging method can find many applications in analytical and bioanalytical chemistry.