Engineered Recombinant Proteins for Aqueous Ultrasonic Exfoliation and Dispersion of Biofunctionalized 2D Materials

Aqueous ultrasonic exfoliation by using proteins as dispersants allows for the simultaneous production and biofunctionalization of single- or few-layered 2D materials for biomedical applications. However, the production yield and quality are always a concern. Here, the production of stable, low-defect, and biofunctionalized 2D flakes of graphene by using bifunctional chimeric polyproteins as dispersants is shown. The chimeric polyproteins contain an amphiphilic protein, hydrophobin (HFBI), to serve as the anchoring point that strongly binds to graphene layers and tandem repeats of a globular protein, GB1, to respond and transmit the ultrasonic force for efficient mechanical exfoliation. For this reason, the production yield is much higher than those obtained by using HFBI alone. Moreover, the yield, lateral size and number of layers can be fine-tuned by the number of GB1 repeats. Other 2D materials, such as MoS₂ and WS₂ , can also be exfoliated in the same manner, demonstrating the versatility of this approach.