Surface Functionalization Of Nanofibrous Membranes From Acrylonitrile Copolymer For Recognition

Molecular recognition is a universal phenomenon existing in biological systems suchas enzyme-substrate recognition,antigen-antibody binding,carbohydrate-proteininteraction.It is characterized by selective binding on the basis of the exact matchbetween two molecules by shape,size and the position of functional groups.Polyacrylonitrile (PAN) has the superior membrane/fiber-forming property andphysicochemical stability,and the electrospun nanofibrous membrane pocesses highsurface area to volume and large porosity.Therefore,PAN-based nanofibrous membraneswith specific recognition capabilities were designed and prepared on the basis of the meritsof PAN and the nanofibrous membrane,which included molecularly imprinted nanofibrousmembrane and glycosylated nanofibrous membrane.The affinity and selectivity of thesenanofibrous membranes were further investigated.The main results of this work aresummarized as below.Poly(acrylonitrile-co-acrylic acid) (PANCAA) and poly(acrylonitrile-co-hydroxyethylmethacrylate) (PANCHEMA) were synthesized,respectively.Theophylline (THO)imprinted PANCAA nanofibrous membranes were fabricated by electrospinning technique.We find that the THO imprinted nanofibrous membranes can selectively induce thecrystallization of THO on its surface.The anlysis of two-dimensional infrared correlationspectroscopy and quantum chemistry calculations confirm that the THO imprintednanofibrous membrane shows a high affinity and selectivity with THO on the basis of thestrong hydrogen bonding and the exactly matched cavities.Chitosan-modified PANCAA nanofibrous membranes were prepared and employed tostudy the specific interaction with concanavalin A (Con A).These chitosan-modifiedPANCAA nanofibrous membranes show strong affinity with Con A.However,theadsorption is not completely reversible.The percent of desorption is less than 50%.Furthermore,glucose was immobilized on the PANCHEMA nanofibrous membranes.The specific interaction between the glucosylated PANCHEMA nanofibrous membranesand Con A was subsequently studied.The results indicate that the glucosylatedPANCHEMA nanofibrous membranes have strong specific affinity and high bindingcapacities to Con A,which is a kind of excellent adsorption and separation material withreversible adsorption capability,repeatability and good mechanical property.The construction of glucosylted surface on the PANCHEMA film was in situmonitored by quartz crystal microbalance (QCM).Meawhile,the association binding constant between the glucose residues and Con A was measured by QCM and surfaceplasmon resonance (SPR),respectively.Accordingly they are 2.86×10⁶ and 4.09×10⁶M^-1,which are much higher than that between single glucose and Con A (0.8×10³ M^-1).These results suggest the feasibility for the construction of a multivalent glucosylationsurface using this method.