Organic Transistor Arrays Integrated with Finger‐Powered Microfluidics for Multianalyte Saliva Testing

Abstract

A compact multianalyte biosensing platform is reported, composed of an organic electrochemical transistor (OECT) microarray integrated with a pumpless "finger-powered" microfluidic, for quantitative screening of glucose, lactate, and cholesterol levels. A biofunctionalization method is designed, which provides selectivity towards specific metabolites as well as minimization of any background interference. In addition, a simple method is developed to facilitate multi-analyte sensing and avoid electrical crosstalk between the different transistors by electrically isolating the individual devices. The resulting biosensing platform, verified using human samples, offers the possibility to be used in easy-to-obtain biofluids with low abundance metabolites, such as saliva. Based on our proposed method, other types of enzymatic biosensors can be integrated into the array to achieve multiplexed, noninvasive, personalized point-of-care diagnostics.

Organic transistor platform with integrated microfluidics for in-line multi-parametric in vitro cell monitoring

“…This analysis can provide a direct evidence of any changes occurring in the cell metabolism and uptake of glucose induced by the FSS. Taking advantage of the facile biofunctionalization of PEDOT:PSS 26 , we implemented a glucose electrochemical biosensor based on our OECTs technology 52 . Figure 3c shows the glucose uptake of the cells over time, for samples collected before and after the 15 h of FSS stimulation at 0.3 dyne cm −2 .…”

“…Typically, 100 μL of the exhausted media from the microfluidics was collected (everỹ 1 h) in a Eppendorf tube for 3 h prior and 6 h after application of a physiological relevant fluid shear stress. With regards to the enzymatic functionalization of the OECT, a PEDOT:PSS planar gate electrode (600 × 600 μm 2 ) was modified with glucose oxidase enzyme based on a previously reported method 30 . Briefly, the gate electrode was plasma activated (25 W, 2 min) to favor covalent attachment of a heterobifunctional silane (GOPS) via condensation reaction.…”

“…OECT technology is also compatible with brightfield and fluorescence high-resolution microscopy as the PEDOT:PSS active layer is optically transparent 35 . Notably, the OECT has also been demonstrated for highly sensitive and specific metabolite sensing from complex media, through biofunctionalization of the gate electrode 26,30,[36][37][38] .…”

“…The working principle of the OECT relies on the direct electrochemical doping/de-doping of the PEDOT:PSS from ions in the electrolyte entering into the active area, upon application of a gate bias ( o0.5 V), thus serving as an efficient ion-to-electron transducer. OECTs have been employed in a wide range of applications, ranging from chemo/bio-sensing 30,31 , to in vivo brain activity recording 29 and in vitro measurements of barrier tissue integrity 32,33 or electrogenic cells 34 . Similar to the commercially available cell-based impedance sensing systems (ECIS, xCelligence), OECTs operating in the AC regime (1 Hz ⩽ ƒ (Hz) ⩽ 20 kHz) can also provide information on two of the most important cell electrical parameters, resistance and capacitance.…”

Biofunctionalization of polydioxythiophene derivatives for biomedical applications

“…Quantification of the binding of PLL was carried out by fluorescence microscopy as before, along with demonstration of preferential binding to the PLL functionalized areas on the PEDOT:PSS film (Figure 6c 64 Thus, the biofunctionalization strategy is designed to generate more sensitive and specific sensing in complex biological fluids.…”