The effect of lightly crosslinked poly(carboxybetaine) hydrogel coating on the performance of sensors in whole blood

Surface coatings of high packing densities have been routinely used to prevent nonspecific biomolecular and microorganism attachment. Hydrogels are another class of low fouling materials used to create three-dimensional matrixes for the free diffusion of small analytes or drugs and the high-loading of bio-recognition elements. However, biomolecules are subject to being entrapped within hydrogel matrixes or adhered onto hydrogel surfaces, making them questionable for use in whole blood. Here, we demonstrate the feasibility of a lightly crosslinked poly(carboxybetaine) hydrogel for use in whole blood, as opposite to the conventional wisdom of high packing density in surface coatings. Proteins are able to diffuse in and out of the matrix freely without being altered from their native conformations. In order to demonstrate its long-term performance in whole blood, this hydrogel was used as the surface coating of a glucose sensor. This work paves a new way for the development of surface coatings and sensors to achieve long-term stability and high performance in whole blood.