Nanomaterial-based miniaturized extraction and preconcentration techniques coupled to matrix-assisted laser desorption/ionization mass spectrometry for assaying biomolecules

• Nanomaterials are successfully integrated into miniaturized extraction methods.
• Nanomaterials acted as affinity probes to enrich biomolecules at µL sample volumes.
• Nanomaterial-based SDME/LLME-MALDI-MS enables detection of analytes at fmol level.
• Nanoparticles in analytical applications for extraction of trace biomolecules.
• Nanomaterial-based MALDI-MS showed the best performance in assaying biomolecules.

Within the past decade, intensive efforts have been devoted to the development of core nanomaterials (NMs) with tunable surface properties and their integration into miniaturized solvent-extraction and sample-preparation methods for extraction, enrichment and preconcentration of ultra-trace biomolecules prior to analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). We summarize the most recent bioanalytical developments that employed NMs as effective probes using solvent microextraction in preconcentration methods coupled with MALDI-MS for assaying biomolecules from complex biological samples. We classify the nanomaterial (NM)-based miniaturized extraction/preconcentration methods into four parts: (1) nanoparticle (NP)-based single-drop microextraction; (2) NP-assisted liquid-liquid microextraction; (3) NMs as affinity and concentrating probes; and, (4) NMs as probes for bacterial analysis. We particularly emphasize efforts on NM-based miniaturized extraction and sample-preparation methods coupled with MALDI-MS for bioassays. Finally, we introduce practical applications of the above approaches.