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 Amplification of Plasmonic Sensor Signal for Cortisol Detection Using Gold Nanoparticles

Herein, gold nanoparticles (AuNP)-modified cortisol-imprinted (AuNP-MIP) plasmonic sensor was developed for signal amplification and real-time cortisol determination in both aqueous and complex solutions. Firstly, the sensor surfaces were modified with 3-(trimethoxylyl)propyl methacrylate and then pre-complex was prepared using the functional monomer N-methacryloyl-L-histidine methyl ester. The monomer solution was made ready for polymerization by adding 2-hydroxyethyl methacrylate to ethylene glycol dimethacrylate. In order to confirm the signal enhancing effect of AuNP, only cortisol-imprinted (MIP) plasmonic sensor was prepared without AuNP. To determine the selectivity efficiency of the imprinting process, the non-imprinted (AuNP-NIP) plasmonic sensor was also prepared without cortisol. The characterization studies of the sensors were performed with atomic force microscopy and contact angle measurements. The kinetic analysis of the AuNP-MIP plasmonic sensor exhibited a high correlation coefficient (R2 = 0.97) for a wide range (0.01–100 ppb) with a low detection limit (0.0087 ppb) for cortisol detection. Moreover, the high imprinting efficiency (k′ = 9.67) of the AuNP-MIP plasmonic sensor was determined by comparison with the AuNP-NIP plasmonic sensor. All kinetic results were validated and confirmed by HPLC

Polymethacryloyl-L-Phenylalanine [PMAPA]-Based Monolithic Column for Capillary Electrochromatography

The ability to detect catecholamines (CAs) and their metabolites is vital to understand the mechanism behind the neuronal diseases. Neurochemistry aims to provide an improved pharmacological, molecular and physiological understanding of complex brain chemistries by analytical techniques. Capillary electrophoresis (CE) is one such analytical technique that enables the study of various chemical species ranging from amino acids and peptides to natural products and drugs. CE can easily adapt the changes in research focus and in recent years remains an applicable technique for investigating neuroscience and single cell neurobiology. The prepared phenylalanine-based hydrophobic monolithic column, Polymethacryloyl-L-phenylalanine [PMAPA], was used as a stationary phase in capillary electrochromatography to separate CAs that are similar in size and shape to each other including dopamine (DA) and norepinephrine (NE) via hydrophobic interactions. Separation carried out in a short period of 17 min was performed with the electrophoretic mobility of 5.54 x 10(-6) m(2) V-1 s(-1) and 7.60 x 10(-6) m(2) V-1 s(-1) for DA and NE, respectively, at pH 7.0, 65% acetonitrile ratio with 100 mbar applied pressure by the developed hydrophobic monolithic column without needing any extra process such as imprinting or spacer arms to immobilize ligands used in separation

Antimicrobial Nanomaterials: A Review

Microbial colonization on various surfaces is a serious problem. Biofilms from these microbes pose serious health and economic threats. In addition, the recent global pandemic has also attracted great interest in the latest techniques and technology for antimicrobial surface coatings. Incorporating antimicrobial nanocompounds into materials to prevent microbial adhesion or kill microorganisms has become an increasingly challenging strategy. Recently, many studies have been conducted on the preparation of nanomaterials with antimicrobial properties against diseases caused by pathogens. Despite tremendous efforts to produce antibacterial materials, there is little systematic research on antimicrobial coatings. In this article, we set out to provide a comprehensive overview of nanomaterials-based antimicrobial coatings that can be used to stop the spread of contamination to surfaces. Typically, surfaces can be simple deposits of nanomaterials, embedded nanomaterials, as well as nanotubes, nanowires, nanocolumns, nanofibers, nanoneedles, and bio-inspired structures

Phenol removal from wastewater by surface imprinted bacterial cellulose nanofibres

In this study, we have reported a novel wastewater treatment technique by phenol imprinted bacterial cellulose (BC-MIP) nanofibres with high specificity and adsorption capacity. N-methacryloyl-(L) phenylalanine methyl ester (MAPA) functional monomer was used to create specific binding sites for the template molecule phenol via electrostatic and hydrophobic interactions. BC-MIP nanofibres were synthesized by surface imprinting approach in the presence of different amounts of total monomer (% weight), monomer/template ratio and polymerization time. Then, the nanofibres were characterized by FTIR-ATR, surface area analysis (BET), elemental analysis, scanning electron microscopy (SEM) and contact angle measurements. Adsorption studies were performed with respect to pH, temperature and ionic strength, and the adsorption capacity was calculated by using the spectrophotometer. In order to desorb the adsorbed phenol from BC-MIP nanofibres, 0.1 M NaCl solution was used. Besides, BC-MIP nanofibres were applied to real wastewater samples from Ergene basin in Turkey. The suitable equilibrium isotherm was determined as Langmuir isotherm. To evaluate the selectivity of the BC-MIP nanofibres, similar molecules were utilized as competitor molecules, which were 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol. Electrostatic interactions were found to contribute to the generation of specific recognition binding sites. The results have shown that imprinting of phenol was achieved successfully with high adsorption capacity. The phenol removal efficiency was reported up to 97%. BC-MIP nanofibres were used 10 times with a negligible decrease in adsorption capacity

Gold-Modified Molecularly Imprinted N-Methacryloyl-(l)-phenylalanine-containing Electrodes for Electrochemical Detection of Dopamine

A molecularly imprinted polymer-based pencil graphite electrode (MIP PGE) sensor, modified with gold nanoparticles, was utilized for the detection of dopamine in the presence of other biochemical compounds using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), depending on its strong electroactivity function. The pulse voltammetry methods recorded the highest response. In addition to the high oxidation rate of DA and the other biomolecule interferences available in the sample matrix used, which cause overlapping voltammograms, we aimed to differentiate them in a highly sensitive limit of detection range. The calibration curves for DA were obtained using the CV and DPV over the concentration range of 0.395–3.96 nM in 0.1 M phosphate buffer solution (PBS) at pH 7.4 with a correlation coefficient of 0.996 and a detection limit of 0.193 nM. The electrochemical technique was employed to detect DA molecules quantitatively in human blood plasma selected as real samples without applying any pre-treatment processes. MIP electrodes proved their ability to detect DA with high selectivity, even with epinephrine and norepinephrine competitor molecules and interferences, such as ascorbic acid (AA). The high level of recognition achieved by molecularly imprinted polymers (MIPs) is essential for many biological and pharmaceutical studies

Poly(vinyl alcohol)/polyethyleneimine (PVA/PEI) blended monolithic cryogel columns for the depletion of haemoglobin from human blood

We have synthesized PVA/PEI monolithic cryogel columns chelated with Cu2+ ions as a model adsorbent, which is capable of binding haemoglobin (Hb) from human blood. The goal of this study is to perform the depletion of Hb via a single and easy process to be useful in proteomic studies. PVA/PEI-Cu2+ cryogel columns were subjected to adsorption studies of Hb from both aqueous solution and human plasma to evaluate the extent of interaction between cryogel columns and Hb. The effects of experimental parameters, such as pH, Hb equilibrium concentration, adsorption time, temperature, and ionic strength, on Hb adsorption capacity were investigated