Selective Detection of Penicillin G Antibiotic in Milk by Molecularly Imprinted Polymer-Based Plasmonic SPR Sensor.

Molecularly imprinted polymer-based surface plasmon resonance sensor prepared using silver nanoparticles was designed for the selective recognition of Penicillin G (PEN-G) antibiotic from both aqueous solution and milk sample. PEN-G imprinted sensors (NpMIPs) SPR sensor was fabricated using poly (2-hydroxyethyl methacrylate-N-methacroyl-(L)-cysteine methyl ester)-silver nanoparticles-N-methacryloyl-L-phenylalanine methyl ester polymer by embedding silver nanoparticles (AgNPs) into the polymeric film structure. In addition, a non-imprinted (NpNIPs) SPR sensor was prepared by utilizing the same polymerization recipe without addition of the PEN-G template molecule to evaluate the imprinting effect. FTIR-ATR spectrophotometer, ellipsometer, contact angle measurements were used for the characterization of NpMIPs SPR sensors. The linear concentration range of 0.01-10 ng/mL PEN-G was studied for kinetic analyses. The augmenting effect of AgNPs used to increase the surface plasmon resonance signal response was examined using polymer-based PEN-G imprinted (MIPs) sensor without the addition of AgNPs. The antibiotic amount present in milk chosen as a real sample was measured by spiking PEN-G into the milk. According to the Scatchard, Langmuir, Freundlich and Langmuir-Freundlich adsorption models, the interaction mechanism was estimated to be compatible with the Langmuir model.

Selective recognition of nucleosides by boronate affinity organic-inorganic hybrid monolithic column.

Boronic acids are important ligands used to selectively recognize and enrich compounds containing cis-diol groups such as nucleosides. In the present study, organic-inorganic hybrid [POSS-MAH-BPA] monolithic column was prepared for the first time in the literature as a new boronate affinity system for the recognition of nucleosides. The selectivity of the [POSS-MAH-PBA] boronate affinity monolithic column for the recognition of cis-diol containing adenosine nucleoside from its analogue molecule of deoxyadenosine triphosphate, dATP, non-cis-diol containing compound was investigated both by UV and HPLC studies. When the relative selectivity coefficients are compared, the [POSS-MAH-PBA] boronate affinity monolithic column is 4.25 times more selective for adenosine than [POSS-MAH] monolithic column. Besides, to determine endogenous nucleosides in biological fluids, which may serve as non-invasive cancer biomarkers, nucleosides were spiked into the urine solutions and passed through the [POSS-MAH-PBA] boronate affinity monolithic column, and the nucleosides were confirmed by HPLC. The adenosine recognition capability of the [POSS-MAH-PBA] boronate affinity monolithic column with an average enrichment factor of 48.9-fold was apparently superior to that of the [POSS-MAH] monolithic column. Methacryl Polyhedral Oligomeric Silsesquioxanes (POSS-MA) with nano-sized stable 3-dimensional architectures provided the advantage of being used as an adsorbent for the monolithic structure by providing high surface area, 507.60 m2/g, and enabling vinyl groups to function with amino acid-based MAH monomers capable of providing electrons to coordinate PBA. Recovery results of more than 90% for adenosine showed that the [POSS-MAH-PBA] boronate affinity monolithic column could be a promising adsorbent for selective adsorption of cis-diol containing compounds such as nucleosides.

Molecularly imprinted cryogel cartridges for the selective recognition of tyrosine.

Molecularly imprinted polymers are used for creating a specific cavity and selective recognition sites for the structure of a target molecule in a polymeric structure. In this study, specific molecularly imprinted cryogel cartridges were synthesized using two distinct functional monomers to compare imprinting efficiency for the selective recognition of Tyrosine (Tyr). Tyr-imprinted cryogel cartridge (MIP1) was prepared using metal-chelate coordination for the imprinting process by free-radical bulk polymerization under frozen conditions, and Tyr-imprinted cryogel cartridge (MIP2) was prepared in the same way using hydrophobic effects for imprinting. After the characterization of the cryogel cartridges was carried out, the optimum adsorption conditions of both were determined according to the different parameters such as flow rate (0.5-2.5 ml/min), pH of the medium (4.0-8.0), initial Tyr concentration (0.1-3.0 mg/ml), and temperature (4-45°C). Selectivity experiments of Tyr-imprinted and non-imprinted cryogel cartridges were carried out by using phenylalanine, tryptophan, and cysteine. Besides, the eluted Tyr from MIP1 and MIP2 cryogel cartridge were applied to FPLC system. Also, the reusability experiments of Tyr-imprinted cryogel cartridges was observed no significant decrease in the adsorption capacity.

Catalase purification from rat liver with iron-chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-glutamic acid) cryogel discs.

In this study, iron-chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-glutamic acid) (PHEMAGA/Fe(3+)) cryogel discs were prepared. The PHEMAGA/Fe(3+) cryogel discs were characterized by elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, swelling tests, and surface area measurements. The PHEMAGA/Fe(3+) cryogel discs had large pores ranging from 10 to 100 µm with a swelling degree of 9.36 g H2O/g cryogel. Effects of pH, temperature, initial catalase concentration, and flow rate on adsorption capacity of the PHEMAGA/Fe(3+) cryogel discs were investigated. Maximum catalase adsorption capacity (62.6 mg/g) was obtained at pH 7.0, 25°C, and 3 mg/ml initial catalase concentration. The PHEMAGA/Fe(3+) cryogel discs were also tested for the purification of catalase from rat liver. After tissue homogenization, purification of catalase was performed using the PHEMAGA/Fe(3+) cryogel discs and catalase was obtained with a yield of 54.34 and 16.67 purification fold.

Removal of iron by chelation with molecularly imprinted supermacroporous cryogel.

Iron chelation therapy can be used for the selective removal of Fe(3+) ions from spiked human plasma by ion imprinting. N-Methacryloyl-(L)-glutamic acid (MAGA) was chosen as the chelating monomer. In the first step, MAGA was complexed with the Fe(3+) ions to prepare the precomplex, and then the ion-imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-glutamic acid) [PHEMAGA-Fe(3+)] cryogel column was prepared by cryo-polymerization under a semi-frozen temperature of - 12°C for 24 h. Subsequently, the template, of Fe(3+) ions was removed from the matrix by using 0.1 M EDTA solution. The values for the specific surface area of the imprinted PHEMAGA-Fe(3+) and non-imprinted PHEMAGA cryogel were 45.74 and 7.52 m(2)/g respectively, with a pore size in the range of 50-200 µm in diameter. The maximum Fe(3+) adsorption capacity was 19.8 µmol Fe(3+)/g cryogel from aqueous solutions and 12.28 µmol Fe(3+)/g cryogel from spiked human plasma. The relative selectivity coefficients of ion-imprinted cryogel for Fe(3+)/Ni(2+) and Fe(3+)/Cd(2+) were 1.6 and 4.2-fold greater than the non-imprinted matrix, respectively. It means that the PHEMAGA-Fe(3+) cryogel possesses high selectivity to Fe(3+) ions, and could be used many times without significantly decreasing the adsorption capacity.