Rebinding Capacity Research Articles

Molecularly imprinted composite membranes with the dual imprinted network for highly selective separation of acteoside

Acteoside (ACT) is the main active ingredient in phenylethanoid glycosides (PhGs) and it has anti-inflammatory, liver-protecting, and memory-enhancing functions. It remained a challenge to develop an imprinted membrane with high permselectivity for separation of ACT from PhGs. In this paper, ACT was used as a template molecule to design dual imprinted molecularly imprinted composite membranes (DIMICMs). The dual imprinted network structure was constructed and played a vital role in DIMICMs. On one hand, ACT imprinted network was formed on the surface of ACT-KH570/PDA/CMK-3@PVDF, and it can recognize and adsorb ACT. On the other hand, the imprinted filler ACT-KH570/PDA/CMK-3 was mixed with PVDF powder to construct the ACT imprinted network in the membrane, and the imprinted network can further recognize and accommodate the ACT. The dual imprinted network acted synergistically for dual recognition of ACT. The result showed that the DIMICMs had the high permselectivity (β = 14.61), selectivity (α = 4.64) and rebinding capacity (105.58 mg/g). The designed approach of DIMICM with a dual imprinted network provided a strategy for the separation of natural products.

Constructing multiple capture domains in molecularly imprinted nanocomposite membranes by flower-like covalent organic framework for separation of acteoside

The selective separation of bioactive components by molecularly imprinted nanocomposite membranes (MINMs) has attracted widespread attention, but the traditional MINMs often were confronted with low rebinding capacity. Herein, the flower-like covalent organic framework (FL-COF) based-molecularly imprinted nanocomposite membranes (FMINMs) with multiple capture domains were developed for separation of acteoside (ACT). The multiple capture domains of FMINMs were constructed by the following three different domains: Firstly, the imprinted layer of FMINMs constructed the imprinted capture domain for specific capture of ACT, improving separation performance of FMINMs for ACT. Secondly, the amino groups on the surface of petals of FL-COF formed affinity capture domain to enrich ACT during the adsorption process, enhancing rebinding capacity and permselectivity of FMINMs for ACT. Thirdly, the hollow structure of FL-COF provided a large spatial capture domain for accommodating ACT, thus enhancing the rebinding capacity of FMINMs. Consequently, the FMINMs with multiple capture domains exhibited high separation performance with rebinding capacity (141.47 mg/g) and permselectivity (βECH/ACT=8.25) of ACT. It demonstrated that designed MINMs with multiple capture domains has great potential for efficient separation of bioactive components.

Preparation of a surface molecularly imprinted thermo-sensitive polymer for selective trypsin capture

Molecularly imprinted polymers (MIPs) are innovative porous materials created through polymerization templating methods for highly selective, sensitive detection and separation of the desired chemical species, known as template molecules. Surface imprinting over nano-sized substrates with special functional groups is an effective approach for improving the mass transfer and rebinding capacity. In this study, we successfully performed surface imprinting using methacrylic acid (MAA) and thermoresponsive N-isopropyl acrylamide (NIPAm) as functional monomers on acrylic-functionalized silica nanoparticles and served as a Trypsin artificial receptor. The resulting Trypsin imprinted polymer exhibited a binding capacity of 1022.44 mg/g, surpassing the non-imprinted polymer’s capacity of 292.41 mg/g within 45 min. Moreover, the imprinting factor, the main influence factor in MIP performance, was 3.5, demonstrating the significant selectivity of the polymeric products. In addition, due to the temperature sensitivity of NIPAm the template removing process was simply done by changing pore size. The silica nanoparticles and the synthesized MIP particles had diameters of approximately 95 nm and 105 nm, respectively, with the polymer layer thickness being around 5 nm. The MIP adsorption model followed the Freundlich isotherm and pseudo-second-order kinetics resulting in efficiencies of 93.0 % and 95.4 %, respectively. The developed Trypsin imprinted polymer was reusable for four consecutive uses,demonstrating both resilience and selectivity towards Trypsin.

Constructing labyrinth structure in molecularly imprinted composite membranes for efficiently separating acteoside

Molecular imprinted composite membranes (MICMs) had attracted much attention in the field of selective separation for bioactive components of natural products. However, it remained a challenge to improve the separation performance of MICMs. Herein, multi-chamber carbon cubes (MCCBs) were synthesized and introduced into polyvinylidene fluoride (PVDF) powders to construct labyrinth structure in molecularly imprinted composite membranes (LMICMs), which were used for efficiently separating acteoside (ACT). The constructed labyrinth structure had complex multidimensional transport routes to trap abundant ACT molecules in LMICMs, thereby improving the rebinding capacities and permselectivity of LMICMs. Meanwhile, the prepared MCCBs with multi-chamber structure can provide a great accommodation space, improving the rebinding capacities of LMICMs. In addition, the labyrinth structure with the large interface resulted in the creation of numerous ACT-imprinted sites and cavities (ACT-ISC) in LMICMs, thus increasing the permselectivity of LMICMs to ACT. Importantly, it was no surprise that large rebinding capacity (154.74 mg/g), excellent rebinding selectivity (4.52) and high permselectivity (14.88) were successfully achieved. It was of great value to design LMICMs with labyrinth structure for efficiently separating of bioactive components from natural products.

Fabricating Ultrathin Imprinting Layer for Fast Capture of Valsartan via a Metal Affinity-Oriented Surface Imprinting Method.

Rapid separation and enrichment of targets in biological matrixes are of significant interest in multiple life sciences disciplines. Molecularly imprinted polymers (MIPs) have vital applications in extraction and sample cleanup owing to their excellent specificity and selectivity. However, the low mass transfer rate, caused by the heterogeneity of imprinted cavities in polymer networks and strong driving forces, significantly limits its application in high-throughput analysis. Herein, one novel metal affinity-oriented surface imprinting method was proposed to fabricate an MIP with an ultrathin imprinting layer. MIPs were prepared by immobilized template molecules on magnetic nanoparticles (NPs) with metal ions as bridges via coordination, and then polymerization was done. Under the optimized conditions, the thickness of the imprinting layer was merely 1 nm, and the adsorption toward VAL well matched the Langmuir model. Moreover, it took just 5 min to achieve adsorption equilibrium significantly faster than other reported MIPs toward VAL. Adsorption capacity still can reach 25.3 mg/g ascribed to the high imprinting efficiency of the method (the imprinting factor was as high as 5). All evidence proved that recognition sites were all external cavities and were evenly distributed on the surface of the NPs. The obtained MIP NPs exhibited excellent selectivity and specificity toward VAL, with good dispersibility and stability. Coupled with high-performance liquid chromatography, it was successfully used as a dispersed solid phase extraction material to determine VAL in serum. Average recoveries are over 90.0% with relative standard deviations less than 2.14% at three spiked levels (n = 3). All evidence testified that the MIPs fabricated with the proposed method showed a fast trans mass rate and a large rebinding capacity. The method can potentially use high-throughput separation and enrichment of target molecules in batch samples to meet practical applications.

Unlocking New Avenues: Solid-State Synthesis of Molecularly Imprinted Polymers.

Molecularly imprinted polymers (MIPs) are established artificial molecular recognition platforms with tailored selectivity towards a target molecule, whose synthesis and functionality are highly influenced by the nature of the solvent employed in their synthesis. Steps towards the "greenification" of molecular imprinting technology (MIT) has already been initiated by the elaboration of green MIT principles; developing MIPs in a solvent-free environment may not only offer an eco-friendly alternative, but could also significantly influence the affinity and expected selectivity of the resulting binding sites. In the current study the first solvent-free mechanochemical synthesis of MIPs via liquid-assisted grinding (LAG) is reported. The successful synthesis of the imprinted polymer was functionally demonstrated by measuring its template rebinding capacity and the selectivity of the molecular recognition process in comparison with the ones obtained by the conventional, non-covalent molecular imprinting process in liquid media. The results demonstrated similar binding capacities towards the template molecule and superior chemoselectivity compared to the solution-based MIP synthesis method. The adoption of green chemistry principles with all their inherent advantages in the synthesis of MIPs may not only be able to alleviate the potential environmental and health concerns associated with their analytical (e.g., selective adsorbents) and biomedical (e.g., drug carriers or reservoirs) applications, but might also offer a conceptual change in molecular imprinting technology.

Nanopore surface engineering of molecular imprinted mesoporous organosilica for rapid and selective detection of L-thyroxine

To develop a biosensing platform for precise diagnosis and management of thyroid-related diseases, the sensitive and selective recognition and identification of L-thyroxine (T4), a thyroid hormone, remains challenging. We herein introduce T4-imprinted mesoporous organosilica (T4-IMO) for sensitive and specific detection of T4 via the sophisticated engineering of pore surfaces using additives with different polarities. The pore surface of T4-IMO emitting a stable fluorescence signal is simply modified by fixed additives. Additives embedded in the pore surface promote the rebinding response of T4 into the recognized cavities, subsequently sensitizing T4 detection. Notably, T4-IMO containing abundant fluorine elements on the pore surface shows a high affinity toward T4, remarkably boosting the rebinding capacity. In addition to good selectivity to T4, the “turn-off” fluorescent signal exhibits a linear relationship with the logarithm of T4 concentration in a range of 0–500nM with a detection limit of 0.47nM in synthetic urine samples. Our findings can establish an insightful strategy for the rational design of molecular-recognition-based sensor systems for the selective and sensitive detection of target analytes.

Constructing bilayer-mesoporous structure in molecularly imprinted nanocomposite membranes for efficient separation of acteoside

The main active component of Cistanche tubulosa is acteoside (ACT), which is difficult to separate due to its low content. Therefore, it is important to develop an efficient method for efficient separation of ACT. Herein, the ACT-based molecularly imprinted nanocomposite membranes (A-MINMs) doped with bilayer-mesoporous carbon nanospheres (BMCNs) were fabricated for efficient separation of ACT. The designed BMCNs mixed with polyvinylidene fluoride (PVDF) powders to prepare the hybrid membranes (BMCNs@PVDF) by a phase inversion method. Then, a sol–gel method was used to synthesize the ACT-imprinted layer on the BMCNs@PVDF. The A-MINMs-400 synthesized under the given conditions demonstrated an excellent rebinding capacity of 114.94 mg/g, the brilliant permselectivity of 7.15, and the rebinding selectivity of 4.48. It mainly attributed to the following three reasons: (i) The designed BMCNs possessed a well-defined bilayer-mesoporous structure composed of the mesoporous carbon shell, interlayer void, and mesoporous carbon core. This bilayer-mesoporous structure can construct the efficient shell@void@core@void@shell pathways in A-MINMs for intercepting ACT molecules through the A-MINMs. (ii) The interlayer void structure can provide a large space for accommodating ACT molecules, thereby enhancing the rebinding capacities of A-MINMs. (iii) The introduced BMCNs nanofillers facilitated to form the abundant ACT-imprinted sites and cavities, improving the selectivity of A-MINMs for ACT. Therefore, the development and design of A-MINMs with bilayer-mesoporous nanofillers had a great potential for efficient separation of bioactive active constituents from natural products.

Molecularly imprinted composite membranes with interleaved imprinted network structure for highly selective separation of acteoside

Acteoside (ACT) is one of the phenylethanoid glycosides in Cistanche tubulosa. The ACT molecules have high medicinal value, but the content of ACT is scarce. Therefore, it is imperative to develop the ACT-based molecularly imprinted composite membranes (A-MICMs) with highly selective separation of ACT. In this study, the amine-polyhedral oligomeric sesquisiloxanes (NH2-POSS) were uniformly introduced into polydopamine modified polyvinylidene fluoride (pDA@PVDF) membranes to fabricate NH2-POSS-pDA@PVDF. Then, the ACT-imprinted layers were synthesized on the surface of NH2-POSS-pDA@PVDF to obtain A-MICMs. The results showed that the optimal conditions were 180 mg DA, 12 h DA self-polymerization time, 400 mg NH2-POSS and 10 h washing time for the synthesis of A-MICMs. The results of adsorption isotherm experiments showed that there was a single layer adsorbate analyte on the A-MICMs. The results of adsorption kinetic experiments showed that chemisorption mechanism played a major function in the adsorption process of A-MICMs for ACT. The A-MICMs exhibited the maximum rebinding capacity of 98.37 mg⋅g−1, an excellent rebinding selectivity of 4.63, and the permselectivity of 7.02. The same A-MICMs kept 95.99% of the maximum rebinding capacity for ACT after 5 adsorption-desorption cycles. The designed A-MICMs with the interleaved imprinted network structure have a potential to be applied to the highly selective separation of bioactive components from natural products.

Permselective and transparent wooden membrane with artemisinin-imprinted nanocages based on a MOFs@C3N4 self-assembly design

Molecularly imprinted membranes have superior selective separation capacity, rebinding capacity, and flux due to their microporous substrates and tightly packed molecularly imprinted polymers. In current study, artemisinin (Ars), the most effective antimalarial drug, is used as template molecule. The permeation-selectivity wooden membranes based on Ars-imprinted nanocages designed by metal organic framework@carbon nitride self-assembly process (MDWMs) has been successfully prepared: (i) based on three-dimensional mesoporous basswood membranes, dopamine-based auto-polymerization process was developed on basswood to for harvest the first layer imprinting and secondary reaction platform. (ii) The two-dimensional sheet carbon nitride modified by metal-organic framework is stably loaded on the surface of the polydopamine-modified basswood membrane, providing a rich irregular point array structure for the formation of recognition sites. Based on elaborate designs and optimizations, selectivity, rebinding capabilities, and flux are enhanced on the developed MDWMs (βAre/Ars = 6.49, βAru/Ars = 4.22, βDH-Ars/Ars = 7.42), and high regeneration rate (>94% after 10 cycles) indicates that MDWMs have superior selectivity and stability. The MDWMs and preparation strategies developed here will provide a completely new design methodology for subsequent selective separation of Ars.

Biomimetic Dual-Layer Imprinted UiO-66-Based Basswood Membranes for Ibuprofen Recognition and Separation

MOF/basswood-based nanocomposite molecularly imprinted membranes had been smoothly compounded on the surface of three-dimensional (3D) basswood materials. Metal–organic framework (MOF) UiO-66-based particles were uniformly encapsulated onto the 3D basswood membranes (BMs) by pretreating basswood with sodium hydroxide (NaOH). The polydopamine (PDA)-based imprinting structure was initially prepared on the as-obtained UiO-66-modified basswood at the first time. A sol–gel imprinting course was then implemented to gain the biomimetic double-layer imprinting based on MOFs grown in situ on BMs (BD-MOF/BMs). Importantly, ibuprofen (IBP) was used as the template molecule throughout the whole dual-imprinted process. Therefore, the sandwich-like double-imprinted layers of IBP could be finally constructed in the BD-MOF/BMs. Abundant IBP-imprinted sites had been obtained in BD-MOF/BMs based on the in situ growth of UiO-66 and dual-imprinted processes, in which the as-prepared BD-MOF/BMs showed particularly high rebinding capacity (120.6 mg g–1) and fast adsorption kinetics. Moreover, the as-prepared PDA-modified surface was not only employed for the first IBP-imprinted layers but also applied to the further construction of the subsequent imprinting sites of IBP; the as-obtained permselectivity coefficients of BD-MOF/BMs were all more than 4.8 based on the selective separation experiments. The stability of the membrane was continuously assessed using dynamic permeation. Finally, the aforementioned experimental results and the approach to environmental protection synthesis demonstrate that our method of BD-MOF/BM synthesis holds significant promise for use in a variety of fields, including selective separation, the chemical industry, the environment, and others.

Thermal Pyocyanin Sensor Based on Molecularly Imprinted Polymers for the Indirect Detection of Pseudomonas aeruginosa

Pseudomonas aeruginosa is a ubiquitous multi-drug-resistant bacterium, capable of causing serious illnesses and infections. This research focuses on the development of a thermal sensor for the indirect detection of P. aeruginosa infection using molecularly imprinted polymers (MIPs). This was achieved by developing MIPs for the detection of pyocyanin, the main toxin secreted by P. aeruginosa. To this end, phenazine was used as a dummy template, evaluating several polymeric compositions to achieve a selective MIP for pyocyanin recognition. The sensitivity of the synthesized MIPs was investigated by UV-vis analysis, with the best composition having a maximum rebinding capacity of 30 μmol g-1 and an imprinting factor (IF) of 1.59. Subsequently, the MIP particles were immobilized onto planar aluminum chips using an adhesive layer, to perform thermal resistance measurements at clinically relevant concentrations of pyocyanin (1.4-9.8 μM), achieving a limit of detection (LoD) of 0.347 ± 0.027 μM. The selectivity of the sensor was also scrutinized by subjecting the receptor to potential interferents. Furthermore, the rebinding was demonstrated in King's A medium, highlighting the potential of the sensor for the indirect detection of P. aeruginosa in complex fluids. The research culminates in the demonstration of the MIP-based sensor's applicability for clinical diagnosis. To achieve this goal, an experiment was performed in which the sensor was exposed to pyocyanin-spiked saliva samples, achieving a limit of detection of 0.569 ± 0.063 μM and demonstrating that this technology is suitable to detect the presence of the toxin even at the very first stage of its production.

Precise identification and transport of specific molecules through framework-functionalized membranes with multiple binding sites

Membranes with specific-recognition and superfast-filtration have significant practical applications in water purification and chiral separation. However, membrane technique still remains challenging to high selectivity and permeation in aqueous-and-organic solvents. Here, we reported a new approach to designing framework-functionalized membranes with multiple binding sites (FMMBSs) that enabled structure&size-exclusion selectivity and fast transport performance towards specific compound of shikimic acid (SA). The as-prepared FMMBSs, based on intrinsic core-shell structure of the boronate-affinity sol-gel imprinted polymers, demonstrated that exquisite control over polymerization pattern and functionalization of characteristic membrane construction played important roles in achieving fast molecule transport combined with high molecular selectivity. The superior property of the membrane-based core-shell structure had been initially demonstrated by testing nitrogen adsorption capacity, showing about a 3.0 times higher result (63.65 cm3/g) than that of original membrane (20.71 cm3/g). These framework-functionalized membranes were then regarded as the platforms to construct the FMMBSs through a first-time-developed boronate-affinity sol-gel imprinting strategy. Therefore, the FMMBSs always kept remarkably static rebinding capacity (45.48 mg g−1) and perm-selectivity factors (>10). The dynamic transport results showed that much higher SA-based rebinding capacities than that of other molecules could be still observed under pump-pressure-driven for a long time, which strongly confirmed the preparation of high-efficiency selective membrane separation system. The strategy of introducing framework-functionalized structure on porous membrane would offer a window of opportunity for preparation of high-intensitive selective separation membrane systems not only for continuous high permeability, but also for competitive selectivity.

Preparation of Magnetic Dummy Molecularly Imprinted Meso-Porous Silica Nanoparticles Using a Semi-Covalent Imprinting Approach for the Rapid and Selective Removal of Bisphenols from Environmental Water Samples

Bisphenol compounds (BPs) are a severe threat to humans and creatures; hence it is critical to develop a quick and simple approach for removing trace BPs from water. This research synthesized a novel template–monomer complex, phenolphthalein-(3-isocyanatopropyl)triethoxysilane (PP-ICPTES), as a dummy template, and a molecularly imprinted polymer for bisphenol was made via a semi-covalent approach. By successfully coating the imprinted layer on the Fe3O4@SiO2@mSiO2 structure, a magnetic dummy molecularly imprinted mesoporous silica nanoparticles (m-DMI-MSNPs) with a core-shell structure and superefficient aqueous phase selectivity for bisphenols was synthesized. The morphology and structure of the m-DMI-MSNPs were characterized using transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The prepared m-DMI-MSNPs presented excellent water compatibility and magnetic separation abilities. The m-DMI-MSNPs showed excellent recognition selectivity towards BPs with imprinting factors of 7.6, 8.2, and 7.5 for bisphenol F (BPF), bisphenol E (BPE), and bisphenol A (BPA), respectively. Fast binding kinetics (equilibrium time < 1 min) and a high rebinding capacity (maximum adsorption capacity, 38.75 mg g–1) were observed in the adsorption experiments. More importantly, the m-DMI-MSNPs, which combine good water compatibility, class selectivity, and magnetic separation performance, exhibited excellent performance for the removal of BPF, BPE, and BPA from tap water, mineral water, and sewage water samples, with removal efficiencies in the ranges of 96.6–97.8, 95.6–97.1, and 93.1–95.3%, respectively.

Design of molecularly imprinted nanocomposite membrane for selective separation of lysozyme based on double-faced self-assembly strategy

In recent years, the combination of membranes and nanomaterials has made remarkable progress in separation of proteins. Nevertheless, the current combination methods suffer from the drawbacks of aggregation and embedding of nanomaterials, leading to a loss of membrane performance. In present work, the lysozyme molecularly imprinted nanocomposite membranes (LYZ-MINMs) with uniform and dense carboxyl functionalized mesoporous silica nanoparticles (C-MSNs) layer were successfully prepared by a double-faced self-assembly strategy for selective separation of LYZ from chicken egg white. Notably, the resulted LYZ-MINMs exhibit both promoted hydrophilicity (36.2°) and enhanced rebinding capacity (509 mg g−1) by comparing with the MINMs designed with the blending method. The selectivity of LYZ-MINMs toward LYZ is improved by the sol–gel imprinting process, resulting in a satisfactory rebinding selectivity of 2.98, 3.22 and 3.45 for Cytochrome C, Bovine haemoglobin, and Ovalbumin, respectively. After ten cycles, the high regeneration rate (>90 %) demonstrates the potential of LYZ- MINMs for practical applications. In addition, the practicability of LYZ- MINMs further verified by utilizing diluted egg white. The work shows great promise for next-generation membranes for protein separation.

Multilayer-functionalized molecularly imprinted nanocomposite membranes for efficient acteoside separation

Acteoside (ACT) and echinoside (ECH) had similar structure and property in the phenylethanoid glycosides (PhGs), thus the selective separation of ACT and ECH was a bottleneck problem. In this study, ACT was used as template molecule, and multilayer-functionalized of molecularly imprinted nanocomposite membranes (A-MINMs) were designed to efficient ACT separation. The A-MINMs were fabricated by using polydopamine (PDA), polyethylenimine functionalized mesoporous silica (PEI/MCM-41) and ACT imprinted layer to modify the surface of polyvinylidene fluoride (PVDF). The PDA layer was a stable surface adhesive, and the filler PEI/MCM-41 was uniformly bonded to the PVDF membrane surface, thus constructing the second layer on the membrane surface. The PEI/MCM-41 layer adjusted the pore uniformity of the membrane surface, and contained abundant amino groups, which provided an ACT imprinted platform to trigger the imprinted polymerization to form an imprinted layer. The ACT imprinted layer had a large number of ACT imprinted sites and cavities, which could specifically recognize ACT, realizing the efficient ACT separation. The results indicated the high rebinding capacity (108.74 mg/g) and permselectivity (βACT/ECH = 9.43) of A-MINMs. Therefore, multilayer-functionalized A-MINMs has a potential application prospect in the field of natural product separation membrane materials.

Molecularly Imprinted Ligand-Free Nanogels for Recognizing Bee Venom-Originated Phospholipase A2 Enzyme.

In this study, ligand-free nanogels (LFNGs) as potential antivenom mimics were developed with the aim of preventing hypersensitivity and other side effects following massive bee attacks. For this purpose, poly (ethylene glycol) diacrylate was chosen as a main synthetic biocompatible matrix to prepare the experimental LFNGs. The overall concept uses inverse mini-emulsion polymerization as the main route to deliver nanogel caps with complementary cavities for phospholipase A2 (PLA2) from bee venom, created artificially with the use of molecular imprinting (MI) technologies. The morphology and the hydrodynamic features of the nanogels were confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. The following rebinding experiments evidenced the specificity of molecularly imprinted LFNG for PLA2, with rebinding capacities up to 8-fold higher compared to the reference non-imprinted nanogel, while the in vitro binding assays of PLA2 from commercial bee venom indicated that such synthetic nanogels are able to recognize and retain the targeted PLA2 enzyme. The results were finally collaborated with in vitro cell-viability experiments and resulted in a strong belief that such LFNG may actually be used for future therapies against bee envenomation.

New Insights into High-Performance Nanocomposite Membranes with Threefold-Imprinted Layers for Selective Recognition and Separation.

Herein, we reported on mixed-matrix membranes with polydopamine (PDA)-based threefold-imprinted layers (MMMs-PTIs), in which the dopamine molecules were simultaneously regarded as functional monomers and cross-linking agents during the first-in-class ternary-PDA-based imprinted method. Threefold-ibuprofen-imprinted layers were constructed into and onto the MMMs-PTIs through the phase inversion process, followed by suction filtration strategy, in which the PDA-based ibuprofen-imprinted activated carbon (AC)/SiO2 and TiO2/GO were chosen as fillers. Based on the threefold-imprinted SiO2/AC and polymer and TiO2/GO-loaded structure, rebinding capacities and permselectivity of MMMs-PTIs had been successfully enhanced, and the selective recognition and separation mechanism had been finally evaluated based on the static adsorption/permeation results. Both high rebinding capacity (53.22 mg/g) and adsorption selectivity (α > 2.0) had been achieved. Importantly, as to the permselectivity performance of MMMs-PTIs toward different compounds, the ibuprofen-permeation efficiencies (β value) of MMMs-PTIs reached 4.07, 4.08, and 3.77, respectively. That is to say, remarkable and stable permselectivity performance could be obtained, which demonstrated the successful preparation of good recognizability and permeability toward ibuprofen.

Selective Removal of the Emerging Dye Basic Blue 3 via Molecularly Imprinting Technique.

A molecularly imprinting polymer (MIP) was synthesized for Basic Blue 3 dye and applied to wastewater for the adsorption of a target template. The MIPs were synthesized by bulk polymerization using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA). Basic Blue 3 dye (BB-3), 2,2′-azobisisobutyronitrile (AIBN) and methanol were used as a functional monomer, cross linker, template, initiator and porogenic solvent, respectively, while non-imprinting polymers (NIP) were synthesized by the same procedure but without template molecules. The contact time was 25 min for the adsorption of BB-3 dye from 10 mL of spiked solution using 25 mg polymer. The adsorption of dye (BB-3) on the MIP followed the pseudo-second order kinetic (k2 = 0.0079 mg·g−1·min−1), and it was according to the Langmuir isotherm, with maximum adsorption capacities of 78.13, 85.4 and 99.0 mg·g−1 of the MIP at 283 K, 298 K and 313 K, respectively and 7 mg·g−1 for the NIP. The negative values of ΔG° indicate that the removal of dye by the molecularly imprinting polymer and non-imprinting polymer is spontaneous, and the positive values of ΔH° and ΔS° indicate that the process is endothermic and occurred with the increase of randomness. The selectivity of the MIP for BB-3 dye was investigated in the presence of structurally similar as well as different dyes, but the MIP showed higher selectivity than the NIP. The imprinted polymer showed 96% rebinding capacity at 313 K towards the template, and the calculated imprinted factor and Kd value were 10.73 and 2.62, respectively. In this work, the MIP showed a greater potential of selectivity for the template from wastewater relative to the closely similar compounds.

Wood-based multi-layered porous imprinted membranes with dual-metal composite nanostructures: Synergistic promotion of rebinding capacity, selectivity and permeability

Herein the Ag&TiO2-based propranolol-imprinted layers had been prepared onto basswood membrane surface based on a polydopamine (PDA)-induced self-polymerization/composite strategy. The as-prepared PDA-induced Ag&TiO2-based molecularly imprinted nanocomposite membranes (PAT-MIMs) showed superb specific recognition capability and permselectivity toward the template molecule of propranolol. Thereinto, the natural curved channel of basswood could efficiently promote the diffusion process of propranolol and improve the contact efficiency with surface recognition sites. Describing the entire synthetic strategy, the as-prepared PDA-induced Ag&TiO2-modified basswood-based membrane structure had been regarded as a threefold sol-gel imprinted-initiated system, thus constructing the propranolol-imprinted sites with key properties of high selectivity and rapid specific-recognizability. Therefore, enhanced adsorption performance of 118.6 mg/g, fast adsorption rate (within 30 min) and high permselectivity rates (more than 3.0) had been successfully harvested, which clearly illustrated the successful preparation of high-intensitive recognizability and permeability toward propranolol from complex separation system.