Surface molecularly imprinted organic-inorganic polymers having affinity sites for cholesterol

Thiol-maleimide click reaction-driven imprinted polymer for chiral resolution of indoprofen

Indoprofen (INP) comprises two enantiomers, R- and S-, whose high pharmacological efficacy is realized only in the case of the separated enantiomers. A newly synthesized poly(acrylonitrile-co-divinylbenzene) (PANB)-based sorbent with selective affinity to the S-enantiomer of INP was applied to separate INP racemate. The synthesis was performed by suspension polymerization with low-crosslinked PANB microparticles and by reaction of the inserted nitriles with 1-amino-1H-pyrrole-2,5‑dione (Ma-NH2). The cationic maleimide-hydrazidine was then attached to the polymer particles, followed by its loading with anionic S-INP. In the post-crosslinking, ethane-1,2-dithiol (ETH) was used as a crosslinker through a thiol-maleimide click reaction, which attached the ETH to the maleimide groups in Ma-P. Acidic elution released S-INP enantiomers through specific receptor sites formed in the imprinted polymer particles, S-INP-P. Characterization of the polymers was done by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (13C NMR), and X-ray diffraction (XRD) while the surface morphology of the sorbents was investigated by scanning electron microscope (SEM). Optimum conditions for the enantioselective adsorption indicated that at pH 7, 285 mg/g of S-INP can be extracted. The chiral separation of the INP racemate led to an ee of 85% for R-INP in the first run and 97% for S-INP during elution.

Chiral resolution of (±)-flurbiprofen using molecularly imprinted hydrazidine-modified cellulose microparticles

Flurbiprofen (FP) is one of the non-steroidal anti-inflammatory drugs (NSAIDs) commonly used to treat arthritic conditions. FP has two enantiomers: S-FP and R-FP. S-FP has potent anti-inflammatory effects, while R-FP has nearly no such effects. Herein, molecularly imprinted microparticles produced from hydrazidine-cellulose (CHD) biopolymer for the preferential uptake of S-FP and chiral resolution of (±)-FP were developed. First, cyanoethylcellulose (CECN) was synthesized, and the -CN units were transformed into hydrazidine groups. The developed CHD was subsequently shaped into microparticles and ionically interacted with the S-FP enantiomer. The particles were then imprinted after being cross-linked with glutaraldehyde, and then the S-FP was removed to provide the S-FP enantio-selective sorbent (S-FPCHD). After characterization, the optimal removal settings for the S- and R-FP enantiomers were determined. The results indicated a capacity of 125 mg/g under the optimum pH range of 5-7. Also, S-FPCHD displayed a noticeable affinity toward S-FP with a 12-fold increase compared to the R-FP enantiomer. The chiral resolution of the (±)-FP was successfully attempted using separation columns, and the outlet sample of the loading solution displayed an enantiomeric excess (ee) of 93 % related to the R-FP, while the eluent solution displayed an ee value of 95 % related to the S-FP.

Designing an efficient organic-inorganic hybrid nanocomposite for simultaneous oxidative/adsorptive desulfurization of model and real fuel oils

In this study, an efficient organic-inorganic hybrid nanocomposite was designed for deep oxidative/adsorptive removal of dibenzothiophene (DBT) from model and real fuel oils employing surface molecularly imprinted polymer (SMIP) and mesoporous silica nanoparticles (MSNs). On the surface of silanol-functionalized MCM-48-HPW prepared at different 12-tungstophosphoric acid (HPW wt%) as the oxidation catalyst, an imprinted polymethacrylic acid polymer (PMAA) as a selective adsorbent of DBT was formed using different amounts of DBT template. Then, various oxidant/sulfur molar ratios were applied during the desulfurization reactions according to the central composite design (CCD). The successful synthesis of the optimum SMIP-PMAA@MCM-48-HPW nanocomposite was confirmed by FTIR, XRD, N2-adsorption, SEM, TEM, TGA, and NMR techniques. The desulfurization percentage of the model oil reached 98.54% under the optimum conditions, and the catalyst percentage was found to be the most significant parameter for desulfurization efficiency. Comparison experiments showed that the combined role of oxidation and adsorption had an extensive impact on desulfurization efficiency. Under the optimized conditions, 96% DBT from gasoline was removed by the optimum nanocomposite. The optimum nanocomposite showed good stability and could be reused five times without a remarkable decrease in the desulfurization ability.

Molecularly Imprinted Polymer-Coated Inorganic Nanoparticles: Fabrication and Biomedical Applications

Molecularly imprinted polymers (MIPs) continue to gain increasing attention as functional materials due to their unique characteristics such as higher stability, simple preparation, robustness, better binding capacity, and low cost. In particular, MIP-coated inorganic nanoparticles have emerged as a promising platform for various biomedical applications ranging from drug delivery to bioimaging. The integration of MIPs with inorganic nanomaterials such as silica (SiO₂), iron oxide (Fe₃O₄), gold (Au), silver (Ag), and quantum dots (QDs) combines several attributes from both components to yield highly multifunctional materials. These materials with a multicomponent hierarchical structure composed of an inorganic core and an imprinted polymer shell exhibit enhanced properties and new functionalities. This review aims to provide a general overview of key recent advances in the fabrication of MIPs-coated inorganic nanoparticles and highlight their biomedical applications, including drug delivery, biosensor, bioimaging, and bioseparation.

The Effect of the Synthesis Method on Physicochemical Properties of Selective Granular Polymer Sorbents

Investigation of the effect of the polymer synthesis method on physicochemical properties of sorbents is one of the topical problems in the chemistry of macromolecular compounds that has high scientific and practical interest. Determination of the optimal synthesis method will make it possible to create sorbents with physicochemical properties that led to the realization of effective sorption. In this work, we investigated the effect of synthesis methods (Pickering emulsion polymerization and precipitation polymerization in solution) of granular polymers based on 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate on physicochemical and sorption properties. The synthesis by Pickering emulsion polymerization led to improvement of the n-propyl alcohol diffusion into the polymer network and to the formation of more homogeneous and structurally stable polymer networks. Creating selective polymer networks by Pickering emulsion polymerization compared to precipitation polymerization in solution led to an increase in porosity, creation of more segregated surface of granules, improvement of binding sites availability at the temperature of 37 °C, and formation of the homogeneous sorption surface with high affinity to target molecules at 25 °C and 37 °C. Selective polymers synthesized by both polymerization methods had the largest values of available sorption surfaces areas for target molecules at 37 °C.

Cholesterol removal from human plasma with biologically modified cryogels

In this study, low molecular weight heparin immobilized P(HEMA) cryogels were fabricated for the removal of LDL-C in hypercholesterolemic human plasma. After characterization studies for P(HEMA) cryogels, effects of the parameters including medium pH, CNBr concentration, heparin concentration and contact time on heparin immobilization were investigated. Blood compatibility and cell adhesion tests were also performed, and platelet and leucocyte loss for P(HEMA)-Hp cryogels were found to be 2.95% and 4.91%, respectively. Maximum adsorption capacity for LDL-C from hypercholesterolemic human plasma was found to be 26.7 mg/g for P(HEMA)-Hp cryogel while it was only 1.67 mg/g for bare P(HEMA) cryogel. The P(HEMA)-Hp cryogels exhibit high desorption ratios up to 96% after 10 adsorption-desorption cycles with no significant decrease in the adsorption capacity. The findings indicated that these reusable P(HEMA)-based cryogels proposed good alternative adsorbents for removal of LDL-C.

Cholesterol-imprinted macroporous monoliths: Preparation and characterization

The development of sorbents for selective binding of cholesterol, which is a risk factor for cardiovascular disease, has a great importance for analytical science and medicine. In this work, two series of macroporous cholesterol-imprinted monolithic sorbents differing in the composition of functional monomers (methacrylic acid, butyl methacrylate, 2-hydroxyethyl methacrylate and ethylene dimethacrylate), amount of a template (4, 6 and 8 mol%) used for molecular imprinting, as well as mean pore size were synthesized by in situ free-radical process in stainless steel housing of 50 mm × 4.6 mm i.d. All prepared materials were characterized regarding to their hydrodynamic permeability and porous properties, as well as examined by BET and SEM methods. Imprinting factors, apparent dynamic dissociation constants, the maximum binding capacity, the number of theoretical plates and the height equivalent to a theoretical palate of MIP monoliths at different mobile phase flow rates were determined. The separation of a mixture of structural analogues, namely, cholesterol and prednisolone, was demonstrated. Additionally, the possibility of using the developed monoliths for cholesterol solid-phase extraction from simulated biological solution was shown.