Here, we introduce the first smart plasmonic absorber based on metal-polymer bionanocomposites performing via conformational changes of the biological functional agent i.e. a protein. Such a progress was done through bridging the gaps between nanofluid filtration, plasmonics and bioswitching. Initially, a biofunctionalized nanofibrous membrane was developed that could filter out metal nanoparticles (<100 nm) from an aqueous stream with a high separation efficiency (97%). This approach brings about a breakthrough in applicability of the macroporous nanofibrous membranes for rejection of suspended nanosolids and extends the application area beyond Microfiltration (MF) to Ultrafiltration (UF). This operative filtration in next step leads to a novel synthesis route for plasmonic materials as formation of a smart freestanding metal-polymer bionanocomposite able to act as an omnidirectional black absorber. M. Elbahri thanks the initiative and networking fund of the Helmholtz Associations for providing the financial base of the start-up of his research group. The authors would like to acknowledge Prof. Dr. Gorb for Cryo-SEM imaging of the samples, Stefan Rehders for drawing the 3-D sketch of the membranes, Kristian Bühr for design of water flux measurement setup , Heinrich Böttcher for tensile tests, and Karen-Marita Prause for SEM measurements.

Here, we report development of a novel biofunctionalized nanofibrous membrane which, despite its macroporous structure, is able to separate even trace amounts (as low as 2mg/L) of biomolecules such as protein and enzyme from water with an optimum efficiency of ~90%. Such an extraordinary protein selectivity at this level of pollutant concentration for a nanofibrous membrane has never been reported. In the current study, poly(acrylonitrile-co-glycidyl methacrylate) (PANGMA) electrospun nanofibers are functionalized by a bovine serum albumin (BSA) protein. This membrane is extraordinarily successful in removal of BSA protein and Candida antarctica Lipase B (Cal-B) enzyme from a water based solution. Despite a negligible non-specific adsorption of both BSA and Cal-B to the PANGMA nanofibrous membrane (8%), the separation efficiency of the biofunctionalized membrane for BSA and Cal-B reaches to 88% and 81%, respectively. The optimum separation efficiency at a trace amount of protein models is due to the water-induced conformational change of the biofunctional agent. The conformational change not only exposes more functional groups available to catch the biomolecules but also leads to swelling of the nanofibers thereby a higher steric hindrance for the solutes. Besides the optimum selectivity, the biofunctionalized membranes are highly wettable thereby highly water permeable.

PANGMA nanofibers and nanomats with fiber diameters of 200–300 nanometers were fabricated by electrospinning. Cal‐B was covalently immobilized onto the PANGMA nanomats via three different immobilization routes. The properties of the Cal‐B‐immobilized PANGMA nanomats were assayed and compared with the free Cal‐B. The observed Cal‐B loading on these nanomats is up to ≈50 mg · g−1, and their hydrolytic activity is up to ≈2 500 nmol · min−1 · mg−1, much higher than free enzyme powder and also slightly higher than Novozyme 435. Cal‐B immobilized PANGMA nanomats have better reusability, thermal stability, and storage ability than free Cal‐B. They retain over 50% of their initial activity after 15 cycles, over 65% after 10 h heat incubation, and over 75% after 30 d storage. magnified image

A novel biofunctionalized nanofibrous membrane is developed through immobilization of protein ligands on the surface of nanofibers. The biofunctionalization not only enhances the membrane's structural properties including mechanical and thermal ones but also makes the membrane capable to separate nanoparticles and biomolecules much smaller than the pore size from water efficiently. Upon contact with water, the conformational change of the protein immobilized leads to its swelling, thereby an enlarged functional surface area and a higher steric hindrance capturing the filtrates. In case of filtration of a plasmonic nanoparticle containing suspension, decoration of the membrane with the plasmonic nanoparticles forms a smart bionanocomposite biosensor for detection of protein denaturation. IntroductionMembrane technology for water treatment is steadily gaining very high importance worldwide. This is primarily due to water pollution and dwindling fresh water supplies leading to water scarcity. Water quality has to be controlled to ensure a safer environment by implementing efficient technologies such as advanced membranes offering more output with less input, that is, efficient energy saving membranes. Electrospun nanofibrous membranes (ENMs) that have the potential to be used as advanced membrane systems will be able to remove pollutants from the environment at lower energy and hence cost.1 Energy saving by ENMs derives from their high interconnected porosity leading to a very high permeability.2 Despite an extraordinary permeability, ENMs suffer from low size selectivity. Microfiltration (MF) range pore size of ENMs makes them efficient in removing relatively coarse particles and suspended solids but not tiny substances smaller than the pore size. [3][4][5][6][7] Considering the importance of separation of nanoparticles also organics that can be detrimental to the quality of water systems, optimizing the selectivity of such membranes could be crucial. Accordingly, not only the high permeability of the membrane is preserved but also on the basis of selectivity, the application domain would be extended from MF to ultrafiltration (UF) and even nanofiltration. Long-term functionality, that is, longevity of ENMs with regard to their extraordinary surface area thereby a higher exposed surface to the water streams is dependent on their mechanical stability. Hence, to maximize the efficiency of an ENM, besides the optimization of the selectivity, its mechanical stabilization should be also stressed.Here, we show that through one-single approach, that is, protein functionalization, an ENM can acquire mechanical and thermal stability while showing more optimum selectivity. Inspired by the

In this article, we report the preparation of a kind of novel crosslinked ultrafine fiber by electrospinning of unsaturated polyester macromonomers (UPM) and subsequent thermal crosslinking. The UPM is prepared via a two-step reaction with poly(2-methyl-1,3-propyleneadipate) diol terminated (PMPA), isophoronediisocyanate (IPDI) and 2-hydroxyethyl methacrylate (HEMA). Poly(3-hydroxyl-butyrate-co-3-hydroxylvalerate) (PHBV) is chosen to improve the processability of the UPM. UPM/PHBV blend ultrafine fibers are successfully electrospun with a proper mass ratio of UPM to PHBV in dichloromethane solution. The fibers are thermally crosslinked after electrospinning. Measurement results indicate that the average diameter of the fibers is about 1 mm and the crosslinked fibers have good solvent-stability and thermal-stability. This novel fiber has potential applications in filtration and protective coating.