Simultaneous Unlocking Optoelectronic and Interfacial Properties of C 60 for Ultrasensitive Immunosensing by Coupling to Metal-Organic Framework.

Due to exceptional electron-accepting ability, light-absorption, and a delocalized conjugated structure, buckminsterfullerene (C-60) has attracted fascinating interest in the field of organic solar cells. However, poor delocalization and accumulation of electrons for pristine C-60 in physiological aqueous solution and difficulties in conjugation with biomolecules limit its extended photovoltaic applications in bioassay. Herein, we reported the noncovalent coupling of C-60 to an electronically complementary porphyrin-derived metal-organic framework (PCN-224) with carboxyl-group terminals. Such assembly not only offered a friendly interface for bioconjugation but also resulted in a long-range ordering C-60@PCN-224 donor-acceptor system that demonstrated an unprecedented photocurrent enhancement up to 10 times with respect to each component. As an example, by further cooperating with Nanobodies, the as-prepared C-60@PCN-224 was applied to a photoelectrochemical (PEC) immunosensor for S100 calcium-binding protein B with by far the most promising detection activities. This work may open a new venue to unlock the great potential of C-60 in PEC biosensing with excellent performances.