The Oct. 30th Chemistry & Biochemistry Collquium guest speaker will be Prof. Hao Shen:  Creation and Development of the Electron Spin Catalyst Dr. Shen is an Assistant Professor in the Chemistry & Biochemistry department at Kent State University.

We have introduced a novel form of electron spin catalyst termed coronazymes, which consist of an achiral gold nanoparticle (AuNP) core encased by a surrounding DNA strand. It exhibits exceptional catalytic reactivity and selectivity compared to traditional nanozymes due to the strong binding affinity of the DNA, which also facilitates long-range catalysis on DNA bases instead of the AuNP surfaces. Through the utilization of single-molecule fluorescence spectroscopy and a fluorogenic reaction, we conducted a comprehensive investigation into the reaction kinetics and mechanism of coronazyme. Our findings reveal that a catalytic turnover initiates a charge transfer chain at the AuNP-DNA interface, followed by subsequent charge transfers within the DNA strand and release of charges to the reaction substrate. This charge injection at the interface is governed by chirality-induced spin selectivity (CISS), making the overall reactivity of coronazyme dependent on electron spin. The spin polarization at the interface can be enhanced by an external magnetic field or circularly polarized light (CPL), resulting in CPL-dependent reactivity. Exciting the DNA with CPL that matches its handedness leads to twice the reactivity compared to CPL with mismatched handedness. The chiral DNA hairpin enhances spin polarization as the electrons transfer through the DNA, and this capability is influenced by the conformation of the DNA. By applying external forces to alter the DNA conformation, we effectively modify the efficacy of spin filtering and subsequently control the reactivity of coronazyme. Additionally, we have invented novel instrumentation and developed innovative analytical methodologies for the creation of coronazymes.