Hydrophobin-Assisted One-Step Preparation Of Boron Nitride Quantum Dots For Multifunctional Application

Boron nitride quantum dots(BNQDs)are novel zero-dimensional nanomaterials and attract wide attention in the fields of biological imaging,optical sensors,and electronics,due to its outstanding physical and chemical properties such as excellent optical characteristics,high thermal conductivity,and chemical stability.Currently,it is still in the early stage for the research of BNQDs preparation that include two approaches,the “bottom-up” and the “top-down”.Although,the “top-down” approach is currently the primary mean to prepare BNQDs,it has quite a few disadvantages including complicated preparation steps,poor biocompatibility(due to the use of organic solvents or strong chemicals),low level of functionalization,and poor water solubility.To overcome these disadvantages,this study proposed a novel one-step preparation of BNQDs with ultrasound assisted by an amphiphilic hydrophobin protein HFBI.Then the applications of such HFBI-functionalized BNQDs in the areas of biological imaging and membrane filtration were studied.The specific research content and results are as follows:(1)In this study,functionalized BNQDs were prepared with one-step ultrasonic method,assisted by hydrophobin protein HFBI with high surface tension.Then the physical and chemical properties of such HFBI-functionalized BNQDs were characterized through series of studies,including Zeta,TEM,AFM,XRD,Raman,WCA,FITR,and XPS.The results showed that the concentration of such HFBI-functionalized BNQDs could reach 90 mg/m L in water,which is the highest concentration of BNQDs aqueous solution currently known.Combined with MD,this study also showed that the self-assembly adsorption of HFBI on the surfaces of BNQDs through its hydrophobic patch is crucial to efficiently exfoliate and disperse BNQDs;(2)In this study,the optical and biological properties of HFBI-coated BNQDs were characterized by PLE,PL,TRPL,MTT,ELISA,and confocal.The results showed that the HFBI-coated BNQDs have excellent photoluminescence and strong blue luminescence with a high quantum yield of 21.2%.Then the functional groups formed on the surface of HBFI-coated BNQDs were used to chemically conjugate with antibodies and successfully targeted labeled cytoskeleton protein actin and cell membrane protein CD44;(3)Finally,the HBFI-coated BNQDs was cast into a laminated boron nitride membrane by vacuum filtration,and was tested for its sorting performance.The results showed that the thickness of such laminated boron nitride membrane was only 200 nm,and it had an extremely ultrafast permeation of water and organic solvents.Such membrane can efficiently reject and maintain high permeation of dye molecules larger than 2 nm.The results also showed that this membrane had good stability in various acidic and alkaline environments.The above research results lay the foundation for large-scale green preparation of BNQDs and provide the bases for novel studies of its theory and applications.