Despite being ubiquitous in the fields of chemistry and biology, the ion-specific effects of electrolytes pose major challenges for researchers. A lack of understanding about ion-specific surface interactions has hampered the development and application of materials for (bio-)chemical sensor applications. Here, we show that scaling a silicon nanotransistor sensor down to ~25 nm provides a unique opportunity to understand and exploit ion-specific surface interactions, yielding a surface that is highly sensitive to cations and inert to pH. The unprecedented sensitivity of these devices to Na⁺ and divalent ions can be attributed to an overscreening effect via molecular dynamics. The surface potential of multi-ion solutions is well described by the sum of the electrochemical potentials of each cation, enabling selective measurements of a target ion concentration without requiring a selective organic layer. We use these features to construct a blood serum ionogram for Na⁺, K⁺, Ca²⁺ and Mg²⁺, in an important step towards the development of a versatile, durable and mobile chemical or blood diagnostic tool.

尽管在化学和生物学领域无处不在，但电解质的离子特异性作用对研究人员提出了重大挑战。缺乏对离子特异性表面相互作用的了解，阻碍了（生物）化学传感器应用材料的开发和应用。在这里，我们表明将硅纳米晶体管传感器的尺寸缩小至〜25 nm，为理解和利用离子特定的表面相互作用提供了独特的机会，从而产生了对阳离子高度敏感且对pH呈惰性的表面。这些设备对Na ⁺的空前敏感性二价离子可通过分子动力学归因于过筛作用。多离子溶液的表面电势可以通过每个阳离子的电化学势之和很好地描述，从而可以选择性地测量目标离子浓度，而无需选择性的有机层。我们利用这些功能来构建Na ⁺，K ⁺，Ca ²⁺和Mg ^2+的血清^离子图，这是朝着开发多功能，耐用且可移动的化学或血液诊断工具迈出的重要一步。