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The quantitative analysis of tear analytes in point‐of‐care settings can enable early diagnosis of ocular diseases. Here, a fluorescent scleral lens sensor is developed to quantitatively measure physiological levels of pH, Na+, K+, Ca2+, Mg2+, and Zn2+ ions. Benzenedicarboxylic acid, a pH probe, displays a sensitivity of 0.12 pH units within pH 7.0–8.0. Crown ether derivatives exhibit selectivity to Na+ and K+ ions within detection ranges of 0–100 and 0–50 mmol L−1, and selectivities of 15.6 and 8.1 mmol L−1, respectively. A 1,2 bis(o‐aminophenoxy)ethane‐N,N,‐N',N'‐tetraacetic‐acid‐based probe allows Ca2+ ion sensing with 0.02–0.05 mmol L−1 sensitivity within 0.50–1.25 mmol L−1 detection range. 5‐Oxazolecarboxylic acid senses Mg2+ ions, exhibiting a sensitivity of 0.10–0.44 mmol L−1 within the range of 0.5–0.8 mmol L−1. The N‐(2‐methoxyphenyl)iminodiacetate Zn2+ ion sensor has a sensitivity of 1 µmol L−1 within the range of 10–20 µmol L−1. The fluorescent sensors are subsequently multiplexed in the concavities of an engraved scleral lens. A handheld ophthalmic readout device comprising light‐emitting diodes (LEDs) and bandpass filters is fabricated to excite as well as read the scleral sensor. A smartphone camera application and an user interface are developed to deliver quantitative measurements with data deconvolution. The ophthalmic system enables the assessment of dry eye severity stages and the differentiation of its subtypes.

Multiparametric silicon sensor chips mounted into biocompatible cell culture units have been used for investigations on cellular microphysiological patterns. Potentiometric, amperometric and impedimetric microsensors are combined on a common cell culture surface on the chip with an area of approximately 29 mm2. Extracellular acidification rates (with pH-sensitive field effect transistors, ISFETs), cellular oxygen consumption rates (with amperometric electrode structures) and cell morphological alterations (with impedimetric electrode structures, IDES) are monitored on single chips simultaneously for up to several days. The corresponding test device accommodates six of such sensor chips in parallel, provides electronic circuitry and maintains the required cell culture conditions (temperature, fluid perfusion system). Sensor data are transformed into quantitative information about microphysiologic conditions. The outcome of this transformation as well as reliability and sensitivity in detection of drug effects is discussed. This is the first report on multiparametric cell based assays with data obtained solely with integrated sensors on silicon chips. Those assays are required in different fields of application such as pharmaceutical drug screening, tumor chemosensitivity tests and environmental monitoring.

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