A monolayer nanostructure based on polyhedral oligomeric silsesquioxane and graphene oxide for highly efficient separation of hemoglobin

Herein, monolayer self-assembly of polyhedral oligomeric silsesquioxane (POSS) onto graphene oxide (GO) is facilely achieved by taking advantage of their electrostatic and hydrogen-bonding interaction. Attributed by the rigid nanocage and donor/acceptor effect of POSS, the as-prepared POSS-GO monolayer nanostructure (denoted as PG) shows an ultrathin thickness of 1.6 nm and significantly suppressed stacking. Followed by post-functionalization of Cu2+, the POSS-GO-Cu2+ nanostructure (shortly termed as PGCu) exhibits outstanding performances including hemoglobin specificity, salt tolerance and ultrahigh adsorption capacity (up to 1657.2 mg g−1). Moreover, PGCu is successfully utilized for the separation of hemoglobin from human whole blood with the maintenance of protein activity. The present study furnishes a simple, rapid and cost-efficient route for the fabrication of ultrathin two-dimensional materials with considerable application potentialities for bio-separation and analysis. •An ultrathin two-dimensional nanostructure (PGCu) is prepared based on polyhedral oligomeric silsesquioxane and graphene oxide through a simple and cost-efficient self-assembly approach.•Ultrathin thickness, highly suppressed stacking and abundant adsorption sites endow PGCu with favorable hemoglobin specificity, salt tolerance and ultrahigh adsorption capacity.•The practical application of PGCu is demonstrated by selective separation of hemoglobin from complex biological samples.