The tight regulation of the glucose concentration in the body is crucial for balanced physiological function. We developed an electrochemical transistor comprising an n-type conjugated polymer film in contact with a catalytic enzyme for sensitive and selective glucose detection in bodily fluids. Despite the promise of these sensors, the property of the polymer that led to such high performance has remained unknown, with charge transport being the only characteristic under focus. Here, we studied the impact of the polymer chemical structure on film surface properties and enzyme adsorption behavior using a combination of physiochemical characterization methods and correlated our findings with the resulting sensor performance. We developed five n-type polymers bearing the same backbone with side chains differing in polarity and charge. We found that the nature of the side chains modulated the film surface properties, dictating the extent of interactions between the enzyme and the polymer film. Quartz crystal microbalance with dissipation monitoring studies showed that hydrophobic surfaces retained more enzymes in a densely packed arrangement, while hydrophilic surfaces captured fewer enzymes in a flattened conformation. X-ray photoelectron spectroscopy analysis of the surfaces revealed strong interactions of the enzyme with the glycolated side chains of the polymers, which improved for linear side chains compared to those for branched ones. We probed the alterations in the enzyme structure upon adsorption using circular dichroism, which suggested protein denaturation on hydrophobic surfaces. Our study concludes that a negatively charged, smooth, and hydrophilic film surface provides the best environment for enzyme adsorption with desired mass and conformation, maximizing the sensor performance. This knowledge will guide synthetic work aiming to establish close interactions between proteins and electronic materials, which is crucial for developing high-performance enzymatic metabolite biosensors and biocatalytic charge-conversion devices.
|Original language||English (US)|
|Journal||ACS Applied Materials & Interfaces|
|State||Published - Feb 7 2023|
Bibliographical noteKAUST Repository Item: Exported on 2023-02-10
Acknowledged KAUST grant number(s): ORA-2021-CRG10-4650, OSR-2018-CRG7-3709, REI/1/4577-01, REI/1/5130-01
Acknowledgements: The authors thank Michael Payne and Dr. Daniel Seeman from Brookhaven Instruments for their assistance with ζ potential measurements. S.S. acknowledges the British Council Newton Fund Institutional Links (ref: 337067) for their support. B.C.S. thanks the UK Research and Innovation for Future Leaders Fellowship no. MR/S031952/1 for funding. This publication is based upon work supported by King Abdullah University of Science and Technology (KAUST) under award nos. REI/1/5130-01-01, REI/1/4577-01, OSR-2018-CRG7-3709, and ORA-2021-CRG10-4650. Figure 7 was produced by Ana Bigio, a scientific illustrator at KAUST.
ASJC Scopus subject areas
- Materials Science(all)