Multiplexed MALDI-MS arrays for screening of MIP solid phase extraction materials

The utility of molecularly imprinted polymers for mass spectrometric protein and proteomics analysis

Selective and efficient sample clean-up is important in mass spectrometric protein- and proteomics analyses from biological matrices. Molecularly imprinted polymers (MIPs), polymers prepared to have tailor-made cavities for capture of target analytes may by such represent an interesting alternative for selective clean-up. The present review aims to give an overview of the utility of MIPs for protein capture from biological matrices prior to mass spectrometry (MS) analysis. The application of MIPs in depletion of abundant proteins, in protein and proteotypic peptide capture as well as in capture of post-translational modifications (PTMs) is described and discussed. In addition, an overview of available MIP formats and their advantages and challenges is given, together with an overview of the mass spectrometric techniques used in protein analysis after MIP capture. Overall, the present literature demonstrates that for many applications MIPs for sample clean-up in mass spectrometric protein and proteomics analysis from biological matrices is still not fully matured. MIPs for proteotypic peptide capture is the most mature approach and a method for routine use may be available within the next few years.

Spectrophotometric determination of fluoxetine by molecularly imprinted polypyrrole and optimization by experimental design, artificial neural network and genetic algorithm

A selective method based on molecularly imprinted polymer (MIP) solid-phase extraction (SPE) using UV-Vis spectrophotometry as a detection technique was developed for the determination of fluoxetine (FLU) in pharmaceutical and human serum samples. The MIPs were synthesized using pyrrole as a functional monomer in the presence of FLU as a template molecule. The factors that affecting the preparation and extraction ability of MIP such as amount of sorbent, initiator concentration, the amount of monomer to template ratio, uptake shaking rate, uptake time, washing buffer pH, take shaking rate, Taking time and polymerization time were considered for optimization. First a Plackett-Burman design (PBD) consists of 12 randomized runs were applied to determine the influence of each factor. The other optimization processes were performed using central composite design (CCD), artificial neural network (ANN) and genetic algorithm (GA). At optimal condition the calibration curve showed linearity over a concentration range of 10^-7-10^-8M with a correlation coefficient (R²) of 0.9970. The limit of detection (LOD) for FLU was obtained 6.56×10^-9M. The repeatability of the method was obtained 1.61%. The synthesized MIP sorbent showed a good selectivity and sensitivity toward FLU. The MIP/SPE method was used for the determination of FLU in pharmaceutical, serum and plasma samples, successfully.

MALDIViz: A Comprehensive Informatics Tool for MALDI-MS Data Visualization and Analysis

Recently, mass spectrometry (MS) has emerged as an important tool for high-throughput screening (HTS) providing a direct and label-free detection method, complementing traditional fluorescent and colorimetric methodologies. Among the various MS techniques used for HTS, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) provides many of the characteristics required for high-throughput analyses, such as low cost, speed, and automation. However, visualization and analysis of the large datasets generated by HTS MALDI-MS can pose significant challenges, especially for multiparametric experiments. The datasets can be generated fast, and the complexity of the experimental data (e.g., screening many different sorbent phases, the sorbent mass, and the load, wash, and elution conditions) makes manual data analysis difficult. To address these challenges, a comprehensive informatics tool called MALDIViz was developed. This tool is an R-Shiny-based web application, accessible independently of the operating system and without the need to install any program locally. It has been designed to facilitate easy analysis and visualization of MALDI-MS datasets, comparison of multiplex experiments, and export of the analysis results to high-quality images.

Filter Plate-Based Screening of MIP SPE Materials for Capture of the Biomarker Pro-Gastrin-Releasing Peptide

Affinity-based solid-phase extraction (SPE) is an attractive low-cost sample preparation strategy for biomarker analysis. Molecularly imprinted polymers (MIPs) as affinity sorbents offer unique opportunities for affinity SPE, due to their low manufacturing cost and high robustness. A limitation is the prediction of their affinity; therefore, screening of analyte recovery and specificity within a large range of SPE conditions is important in order to ensure high-sensitivity detection and assay reproducibility. Here, a µ-SPE method for screening of the MIP-SPE materials using a commercial 384-well filter plate is presented. The method allows for rapid and automated screening using 10-30 µL of packed SPE sorbent per well and sample volumes in the range of 10-70 µL. This enables screening of many different SPE sorbents while simultaneously identifying optimal SPE conditions. In addition, the 384-well format also facilitates detection with a multitude of analytical platforms. Performance of the µ-MIP-SPE method was investigated using a series of MIPs designed to capture pro-gastrin-releasing peptide (ProGRP). Fractions coming from sample load, cartridge wash, and elution were collected and analyzed using mass spectrometry (MS). The top-performing MIPs were identified, together with proper SPE conditions.

Solvent-Responsive Molecularly Imprinted Nanogels for Targeted Protein Analysis in MALDI-TOF Mass Spectrometry

Molecular imprinted poly(acrylamido)-derivative nanogels have shown their selectivity to bind the protein human serum transferrin (HTR) and also showed their capability for instantaneous solvent-induced modification upon the addition of acetonitrile. Integrated to matrix-assisted laser desorption/ionization time-of-flight mass analysis the HTR-imprinted solvent-responsive nanogels permitted the determination of HTR straight from serum and offered novel perspectives in targeted protein analysis.