Polymer Mass Research Articles

9-PAN promotes tubulin- and ROS-mediated cell death in human triple-negative breast cancer cells.

To examine the antiproliferative effect of a rationally designed, novel noscapine analogue, 9-((perfluorophenyl)methylene) aminonoscapine, '9-PAN') on MDA-MB-231 breast cancer cell line, and to elucidate the underlying mechanism of action. The rationally designed Schiff base-containing compound, 9-PAN, was characterized using IR, NMR and mass spectra analysis. The effect of the compound on cell viability was studied using an MTT assay. Cell cycle and cell death analyses were performed using flow cytometry. Binding interactions of 9-PAN with tubulin were studied using spectrofluorometry. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were investigated using the probes, DCFDA and rhodamine-123, respectively. Immunofluorescence imaging was used to visualize cellular microtubules. 9-PAN inhibited cell proliferation (IC50 of 20±0.3µm) and colony formation (IC50 , 6.2±0.3µm) by arresting the cells at G2 /M phase of the cell cycle. It bound to tubulin in a concentration-dependent manner without considerably altering the tertiary conformation of the protein or the polymer mass of the microtubules in vitro. The noscapinoid substantially damaged cellular microtubule network and induced cell death, facilitated by elevated levels of ROS. 9-PAN exerts its antiproliferative effect by targeting tubulin and elevating ROS level in the cells.

Abstract 1240: Runx2 promotes microtubule stability for survival of breast cancer bone metastatic cells

Abstract Bone metastasis of breast cancer causes significant patient mortality. During metastasis, breast cancer cells induce autophagy to survive metabolic stress. Although the core components of the autophagy pathway have been characterized, the regulatory mechanism of autophagy in bone metastatic cancer cells is still unknown. To examine autophagy during bone metastasis, we used a bone metastatic isogenic variant of breast cancer MDA-MB-231 cells isolated from a xenograft tumor mouse model of metastasis. Previously, we and others have shown that Runt-related transcription factor-2 (Runx2) promotes cell survival, cell invasion, and metastatic tumor growth associated osteolysis. Therefore, we examined the regulatory mechanisms of Runx2-mediated autophagy for increased cell survival in the bone microenvironment. Our results show that Runx2 promotes microtubule (MTs) stability to enhance autophagy flux. We show that Runx2 silencing significantly decreases acetylated α-Tubulin (Ac-α-Tub) levels. Ac-α-Tub is a marker of stable MTs, which promotes trafficking of autophagosomes. Ac-α-Tub also increases during cellular stress, such as glucose starvation. We found that Runx2 knockdown cells are able to induce Ac-α-Tub upon glucose starvation but are unable to maintain acetylated polymer mass of MTs upon removal of stress. Furthermore, expression of wild type or transcriptionally inactive Runx2 can restore Ac-polymer of MTs in Runx2 knockdown cells, while C-terminal deletion mutant failed to rescue MT polymer mass. Previous studies have shown that the C-terminal of Runx2 serves a scaffolding function by interacting with MTs and multiple proteins including HDAC6, the deacetylase of α-Tubulin. Interestingly, the expression levels of HDAC6 and αTAT1 (α-tubulin acetyltransferase-1) were not altered with Runx2 silencing, suggesting a transcriptionally independent function for Runx2 for maintaining the MTs stability. As MT targeting agents are often used as chemotherapeutics, we found that treatment with vinblastine, a MT disrupting agent, decreases Ac-polymer MTs with Runx2 silencing or expression of C-terminal mutant Runx2, while WT and transcriptionally inactive Runx2 expressing cells exhibit resistance to the treatment. Conversely, treatment with Docetaxel, a MT stabilizing agent, enhances Ac-α-Tub and polymer MTs. Recent reports have also linked high levels of Ac-α-Tub with aggressive breast cancer. We performed immunohistochemistry for Ac-α-Tub levels in bone metastatic patient samples and found significantly strong Ac-α-Tub positive cells in matched and unmatched bone metastatic tumors compared to the primary tumors. Our findings indicate that inhibition of Runx2 may sensitize metastatic tumors to MT targeting agents, and Runx2 and Ac-α-Tub levels may serve as markers for metastatic tumors to help stratify patients for optimal treatment for bone metastatic tumors. Citation Format: Ahmad Othman, Marcus Winogradzki, Manish Tandon, Jitesh Pratap. Runx2 promotes microtubule stability for survival of breast cancer bone metastatic cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1240.

Application of Artificial Neural Networks to Predict the Catalytic Pyrolysis of HDPE Using Non-Isothermal TGA Data.

This paper presents a comprehensive kinetic study of the catalytic pyrolysis of high-density polyethylene (HDPE) utilizing thermogravimetric analysis (TGA) data. Nine runs with different catalyst (HZSM-5) to polymer mass ratios (0.5, 0.77, and 1.0) were performed at different heating rates (5, 10, and 15 K/min) under nitrogen over the temperature range 303–973 K. Thermograms showed clearly that there was only one main reaction region for the catalytic cracking of HDPE. In addition, while thermogravimetric analysis (TGA) data were shifted towards higher temperatures as the heating rate increased, they were shifted towards lower temperatures and polymer started to degrade at lower temperatures when the catalyst was used. Furthermore, the activation energy of the catalytic pyrolysis of HDPE was obtained using three isoconversional (model-free) models and two non-isoconversional (model-fitting) models. Moreover, a set of 900 input-output experimental TGA data has been predicted by a highly efficient developed artificial neural network (ANN) model. Results showed a very good agreement between the ANN-predicted and experimental values (R2 > 0.999). Besides, A highly-efficient performance of the developed model has been reported for new input data as well.

Phosphorylated styrene-butadiene rubber as an adsorbent for the removal of Cd(II) from aqueous solution

ABSTRACT In the present study, the new phosphorylated polymer has been synthesised via chemical modification of styrene-butadiene rubber (SBR). The successful modification of the polymer and the presence of the functional group are determined using Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). The adsorption property of the new polymer towards Cd (II) ions was investigated. The influence of the in/itial concentration of Cd (II) ions, temperature, pH of the solution, polymer mass, contact time between the solid and liquid phases is studied for the understanding of their effect on the sorption process. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models are applied for the experimental data assessment of the sorption isotherms. The kinetic analyses of the sorption processes were evaluated by using pseudo-first-order, pseudo-second-order and intra-particle diffusion models. With the calculation of thermodynamic parameters (free energy, enthalpy, and entropy), it was found that the process has a spontaneous and endothermic nature. The adsorption characteristics of the phosphorylated polymer allow considering that it has potential applications for the removal of the Cd (II) ions from water.

Removal and Separation of Heavy Metal Ions from Multicomponent Simulated Waters Using Silica/Polyethyleneimine Composite Microparticles.

Composite solid surfaces with high content of functional groups (FGs) are useful materials in different types of applications requiring stimuli-responsive "hard/soft" architectures, their improved properties rising from the combination of organic-inorganic parts. Among different types of weak polyelectrolytes, poly(ethyleneimine) (PEI) is of great interest in the construction of composite systems with thin layer-by-layer (LbL) organic films due to the large number of amino groups per unit mass of polymer. Herein, the spherical silica microparticles were modified with linear (L) or branched (B) PEI chains using LbL deposition of a copper complex (PEIL-Cu2+ or PEIB-Cu2+) and poly(acrylic acid) (PAA), glutaraldehyde selective cross-linking, followed by copper and PAA extraction from the multilayer. The newly formed silica/(PEIL)10 and silica/(PEIB)10 composites were used in batch and column sorption/desorption experiments of four heavy metal ions (Cu2+, Ni2+, Co2+, and Cd2+). In noncompetitive conditions ([FG]/Σ[M2+] > 9), all heavy metal ions were retained on composites, demonstrating the potential application of the prepared functional microparticles in surface water treatment. However, in competitive conditions ([FG]/Σ[M2+] < 9), only Cu2+ is sorbed in high amount (∼2.5 mmol·g-1 PEI) on composites, with simultaneous displacement of already sorbed ions, demonstrating the solid-phase extraction and chromatographic properties of the synthesized silica/(PEIL)n and silica/(PEIB)n composites.

A new strategy for the reinforcement of paraffin-based fuels based on cellular structures: The armored grain — Mechanical characterization

Paraffin waxes have been identified as promising hybrid rocket fuels. Though attractive from the ballistic point of view, these materials feature poor mechanical properties and, in particular, a brittle behavior making them unsuitable for application in operating systems. This study introduces a new strategy to enhance the mechanical properties of paraffin-based fuel grains manufactured at lab-scale. The implemented technique is based on the use of a 3D printed reinforcing structure embedded in the paraffin wax matrix and providing mechanical properties to the grain. This is named armored grain. The gyroid, a triply periodic cellular structure, is selected as a suitable reinforcing structure and its mechanical behavior is assessed by experimental and numerical investigations. Different 3D printable materials are considered, focusing the analysis on the differences due to their structural properties, compatibility and wettability with the paraffin fuel. In this paper, the mechanical properties of the gyroid-reinforced grains are evaluated by compression tests. The armored grains performance is compared to the mechanical behavior of fuel formulations in which reinforcement is pursued by blending the paraffin with thermoplastic polymers. The strength of the paraffin wax can be slightly enhanced by the addition of thermoplastic polymers. Under the investigated conditions (polymer mass fraction ≤10%), this reinforcing strategy yields blends with brittle behavior, while the armored grain provides a ductile behavior. The structural response of the armored grain can be tuned by exploiting different 3D printer polymers and relative densities (7%, 10%, 15%) for the gyroid reinforcement. Under the investigated conditions, the higher the relative density the stronger the mechanical properties. Albeit all the investigated polymers for gyroid reinforcement enhance the structural behavior of the paraffin wax, the nylon-based armored grain seems the most promising solution, featuring a 35% yield stress and a 296% yield strain increase over the paraffin baseline.

The Two Phase Transitions of Hydrophobically End-Capped Poly(N-isopropylacrylamide)s in Water.

High-sensitivity differential scanning calorimetry (HS-DSC) thermograms of aqueous poly(N-isopropylacrylamide) (PNIPAM) solutions present a sharp unimodal endotherm that signals the heat-induced dehydration/collapse of the PNIPAM chain. Similarly, α,ω-di-n-octadecyl-PNIPAM (C18-PN-C18) aqueous solutions exhibit a unimodal endotherm. In contrast, aqueous solutions of α,ω-hydrophobically modified PNIPAMs with polycyclic terminal groups, such as pyrenylbutyl (Py-PN-Py), adamantylethyl (Ad-PN-Ad), and azopyridine- (C12-PN-AzPy) moieties, exhibit bimodal thermograms. The origin of the two transitions was probed using microcalorimetry measurements, turbidity tests, variable temperature 1H NMR (VT-NMR) spectroscopy, and 2-dimensional NOESY experiments with solutions of polymers of molar mass (Mn) from 5 to 20 kDa and polymer concentrations of 0.1 to 3.0 mg/mL. The analysis outcome led us to conclude that the difference of the thermograms reflects the distinct self-assembly structures of the polymers. C18-PN-C18 assembles in water in the form of flower micelles held together by a core of tightly packed n-C18 chains. In contrast, polymers end-tagged with azopyridine, pyrenylbutyl, or adamantylethyl form a loose core that allows chain ends to escape from the micelles, to reinsert in them, or to dangle in surrounding water. The predominant low temperature (T1) endotherm, which is insensitive to polymer concentration, corresponds to the dehydration/collapse of PNIPAM chains within the micelles, while the higher temperature (T2) endotherm is attributed to the dehydration of dangling chains and intermicellar bridges. This study of the two phase transitions of telechelic PNIPAM homopolymer highlights the rich variety of morphologies attainable via responsive hydrophobically modified aqueous polymers and may open the way to a variety of practical applications.

Thermocapillary Marangoni Flows in Azopolymers.

It is well known that light-induced multiple trans-cis-trans photoisomerizations of azobenzene derivatives attached to various matrices (polymeric, liquid crystalline polymers) result in polymer mass movement leading to generation of surface reliefs. The reliefs can be produced at small as well as at large light intensities. When linearly polarized light is used in the process, directional photo-induced molecular orientation of the azo molecules occurs, which leads to the generation of optical anisotropy in the system, providing that thermal effects are negligible. On the other hand, large reliefs are observed at relatively strong laser intensities when the optofluidization process is particularly effective. In this article, we describe the competitive thermocapillary Marangoni effect of polymer mass motion. We experimentally prove that the Marangoni effect occurs simultaneously with the optofluidization process. It destroys the orientation of the azopolymer molecules and results in cancelation of the photo-induced birefringence. Our experimental observations of polymer surface topography with atomic force microscopy are supported by suitable modelings.

Systematic Studies on Surface Erosion of Photocrosslinked Polyanhydride Tablets and Data Correlation with Release Kinetic Models.

Photocrosslinkable polyanhydrides that undergo surface erosion are suitable materials for controlled-release drug delivery systems. Investigating the impact of different parameters on their erosion behavior is essential before use in drug delivery systems. Although their synthesis is well-established, parameters that may substantially affect the erosion of thiol-ene polyanhydrides including temperature and pH of the media, the geometry of the polymers, and the media shaking rate (the convective force for the polymer erosion), have not yet been studied. This study explores the effects of different environmental and geometric parameters on mass loss (erosion) profiles of polyanhydrides synthesized by thiol-ene photopolymerization. A comparative study on several release kinetic models fitting is also described for a better understanding of the polymer erosion behavior. The results demonstrated that although the temperature was the only parameter that affected the induction period substantially, the mass-loss rate was influenced by the polymer composition, tablet geometry, temperature, pH, and mass transfer (shaking) rate. With regard to geometrical parameters, polymers with the same surface area to volume ratios showed similar mass loss trends despite their various volumes and surface areas. The mass loss of polyanhydride tablets with more complicated geometries than a simple slab was shown to be non-linear, and the kinetic model study indicated the dominant surface erosion mechanism. The results of this study allow for designing and manufacturing efficient delivery systems with a high-predictable drug release required in precision medicine using surface-erodible polyanhydrides.

The Influence of Heat Treatment on the Quality of Vehicle Component Parts Made of Rigid Polyurethane Foam

The paper provides the results of the investigation in the influence of heat treatment on the quality of vehicle component parts made of rigid polyurethane integral foam. The temperature of heat treatment was based on the exo-peak of the first heat cycle in DSC curve, and was equal to 135 °С. At that temperature, the samples were treated for 2-8 hours, and, as a result, they experienced an abnormal exo-effect in the glass transition region, which was indicative of thermal relaxation. The paper shows that the additional heat treatment stage for parts made of rigid polyurethane integral foam results in an increase in molecular mass of polymer, due to a smaller quantity of end groups, and, thus, in an increase in glass transition temperature from 169 °С to 176 °С. An increase in heat treatment time to 6 hours at 135 °С leads to a higher ultimate bending strength, which reaches its maximum, while further heat treatment (up to 8 hours) lowers this value. Therefore, with a higher degree of cross-linking the fracture toughness increases and passes its maximum, after that it starts to decrease, and the material becomes brittle.

Robust Guanidine Metal Catalysts for the Ring-Opening Polymerization of Lactide under Industrially Relevant Conditions.

The increasing awareness of sustainability has led to enormous growth of the demand for bio-based and biodegradable polymers such as poly(lactide) (PLA). In industry, polymerization of lactide is currently carried out using tin catalysts (e. g., tin(II) ethyl hexanoate, Sn(Oct)2 ). Since the catalyst remains in the polymer, it can accumulate in the soil or in the human body after degradation and cause damage due to its toxicity. Therefore, a search for a suitable substitute for this catalyst has been going on for decades. Guanidine metal complexes prove to be excellent catalysts in the polymerization of lactide. They are not only convincing because of their activity and the synthesis of high molar mass polymers, but also show a high robustness against high temperatures, oxidation as well as residual protic impurities in the monomer. Herein, key zinc and iron guanidine complexes are discussed with respect to their apparent rate constant (kapp ) and rate constant of propagation (kp ), produced molar masses and the mechanism involved.

Molar mass determination of polylactic acid alternatives by capillary viscometry method

The molar mass of polymers is a basic property that defines the appropriate processing method and the field of application of polymers. Therefore, the measurement of molar weights is a crucial point of polymer synthesis. In absence of modern but expensive equipment a rheology-based method can be used to define the molar mass with reliable result. By evaluation of molar mass, the entire polymerization can be monitored and controlled.During my experiments polylactic acid alternatives (PLLA, PDLA, PDLLA) have been synthesized by direct polycondensation methods. According to the relevant literature, by this method and with the adequate setup of its parameters 104-105 g·mol−1 molar mass can be reached. The two most important parameters are the process time and temperature that strongly effects on the value of molar mass of polymer. In this work standard polycondensation method has been used to produce the mentioned polylactic acid alternatives then the molar masses of polylactic acid polymers were calculated by followed the correlation of Mark – Houwink relation.

Molar mass determination of microwave initiated polycondensation produced PLLA by capillary viscometry method

The microwave initiated polycondensation is a new approach for polylactic acid production. The time need of this process is quite less compared to the standard polycondensation process, but the progress and improvement of the molar mass is the most important basic factor.In my earlier work the standard polycondensation has already been investigated, so to be able to compare both methods PLLA has been produced by microwave initiated polycondensation too. The measurement of molar weights is a crucial point of polymer synthesis. According to my earlier work a rheology-based method was used again to define the molar masses during the polymerization process and make the comparison reliable.During my experiments PLLA has been synthesized by microwave initiated polycondensation method. According to the relevant literature, by standard polycondensation 104-105 g·mol−1 molar mass can be reached, so the main question was that how long should be the microwave process run to result the same level of molar mass. During the experiments PLLA samples have been taken according to a special time plan, then solved in chloroform prepared samples with different concentrations for further analysis. To measure the flow-times Ubbelohde capillary viscometer was applied at this time too. Based on the data of viscometry measurements the intrinsic viscosities have been graphically defined then the molar masses of polylactic acid polymers were calculated according to the correlation of Mark – Houwink relation.

Long-Term Evaluation of Dip-Coated PCL-Blend-PEG Coatings in Simulated Conditions.

Our study focused on the long-term degradation under simulated conditions of coatings based on different compositions of polycaprolactone-polyethylene glycol blends (PCL-blend-PEG), fabricated for titanium implants by a dip-coating technique. The degradation behavior of polymeric coatings was evaluated by polymer mass loss measurements of the PCL-blend-PEG during immersion in SBF up to 16 weeks and correlated with those yielded from electrochemical experiments. The results are thoroughly supported by extensive compositional and surface analyses (FTIR, GIXRD, SEM, and wettability investigations). We found that the degradation behavior of PCL-blend-PEG coatings is governed by the properties of the main polymer constituents: the PEG solubilizes fast, immediately after the immersion, while the PCL degrades slowly over the whole period of time. Furthermore, the results evidence that the alteration of blend coatings is strongly enhanced by the increase in PEG content. The biological assessment unveiled the beneficial influence of PCL-blend-PEG coatings for the adhesion and spreading of both human-derived mesenchymal stem cells and endothelial cells.

The Raman spectroscopy approach to the study of Water–Polymer interactions in hydrated hydroxypropyl cellulose (HPC)

Raman spectroscopy was used to investigate molecular interactions and the water binding structure in hydrated hydroxypropyl cellulose Klucel® Pharm HPC type MF. During the study, there were examined samples with water content equal to 0.69, 1.41 and 2.17 g/g. In this case, the water concentration was defined as the ratio of the mass of water to the mass of the dry polymer. The first content was close to the previously determined amount of non-freezing water that was found to be 0.54 g/g (calorimetric studies). The analysis was focused on the O–H stretching band region range from 3600 to 3000 cm−1. The received 3 bands at ca. 3400 cm−1, 3320 cm−1 and 3220 cm−1 were assigned to non-freezing water, freezing bound water and free water respectively. Changes in the 1235-1000 cm−1 glycosidic linkage range were also analyzed as well as in the 3000-2850 cm−1 range of C–H stretching vibrations of the CH2 and CH3 groups. Changes in the asymmetrical CH stretching vibrations of the methylene and symmetrical CH stretching vibrations of CH3 were also discussed.

Biodegradable stent coatings on the basis of PLGA polymers of different molecular mass, sustaining a steady release of the thrombolityc enzyme streptokinase

The work describes synthesis of novel biodegradable polymer membranes based on poly(lactic-co-glycolic acid) (PLGA), as well as testing of their physicochemical properties. The membranes synthesized have been shown to possess the necessary mechanical properties and to be capable of sustained and directed release of large biomacromolecules, in particular, the molecules of streptokinase (m.w. 47 kDa). Streptokinase is a pharmaceutical drug with a high thrombolytic activity. The technology developed allows one to synthesize membranes with a relative elongation of 25 to 165% and a tensile strength of 20 to 55 MPa. The membranes are biodegradable; the rate of the polymer degradation in an isotonic solution is 0.5–1.0% per day. The streptokinase-infused membranes were demonstrated to release the protein in a controlled manner, with ~90% of the enzyme molecules retaining their activity. The rate of streptokinase release from the membranes was in the range of 0.01–0.07 mg/cm2 per day. The polymer films did not exert any short-term toxic effects on the cells cultivated de novo on the film surface. The mitotic index of cells growing on the surface of polymer films was ~1.5%. The implantation of the synthesized polymers in animals – in the form of film samples and as a component of the coating of nitinol stents – had no complications during the postoperative period. The histological examination of the implant-surrounding tissues did not reveal any abnormalities. When the polymers were implanted as separate film samples, only traces of PGLA were detected in the tissues two months after the surgery. The implantation of stents coated with the streptokinase-infused polymers resulted in the formation of a mature and thick connective-tissue capsule. Thus, novel biodegradable PLGA-based polymer membranes have been synthesized and tested in this work – membranes which possess the necessary mechanical properties and are capable of a sustained and directional release of high-molecular biological compounds.

Environmental degradation and efficacy of a sprayable, biodegradable polymeric mulch

Polyethylene (PE) and other non-degradable plastics are used in vast quantities as agriculture mulch to help protect the soil surface, conserve water, and improve soil microclimatic factors. Unfortunately, their continued use poses several environmental problems, so an environmentally friendly solution needs to be found. The use of biodegradable plastics in place of conventional PE is one well studied solution, and here we investigate how different controlled environmental conditions affect the water conservation efficacy, and rate of biodegradation of a novel, biodegradable, sprayable polycaprolactone based polyurethane mulch. The effect of soil moisture content, sunlight, soil type, and polymer pigmentation are investigated using several different characterization techniques and measurements. It was found that the polymer studied is effective at conserving soil moisture, and that it biodegrades at different rates via a bulk erosion mechanism. The rate at which it degrades mostly depends on the soil type to which it is applied, and the moisture content of that soil. This was confirmed using soil CO2 emissions, polymer mass loss, polymer molecular weight reduction, and scanning electron microscopy. Results are discussed.

A sequential design approach for in situ incorporation of cellulose nanocrystals in emulsion-based pressure sensitive adhesives

Cellulose nanocrystals (CNCs) are naturally-sourced nanoparticles that can be used to modify polymers and provide exceptional mechanical properties to nanocomposite materials. In this study, CNCs were incorporated into water-based pressure sensitive adhesives (PSAs) via in situ semi-batch emulsion polymerization to improve PSA properties. A sequential design approach was used to improve CNC/poly(n-butyl acrylate/vinyl acetate) nanocomposite PSAs. In the first part of the design, the effects of acrylic acid (AA) and anionic surfactant sodium dodecyl sulfate (SDS) were examined in the presence of 0.5 wt% CNCs (based on polymer mass). While the SDS was crucial to maintaining latex stability, its excessive addition led to a decrease in PSA performance, namely tack and peel strength. The AA comonomer was pivotal in improving the shear strength of the PSAs, especially in the presence of CNCs. In all cases, the addition of CNCs led to improved PSA shear strength. In the second part of the design, the addition of 1-dodecanethiol (NDM) as a chain transfer agent (CTA) with CNC levels up to 1 wt% led to an improvement in tack and peel strength but at the cost of diminishing the shear strength. Generally, the addition of CNCs improved PSA performance. Thus, to maximize the impact of CNCs on PSA properties, a careful balance of SDS (for latex stability), AA (to improve shear strength) and NDM (to improve tack and peel strength) are needed.

A mass spectrometry imaging method for visualizing synthetic polymers by using average molecular weight and dispersity as indices.

Matrix-assisted laser desorption/ionization mass spectrometric imaging (MSI) is considered to be a powerful tool for visualizing the spatial distribution of synthetic polymers. However, a conventional method extracting an image of a specific m/z value is not suitable for polymers, which have a mass distribution. It is necessary to develop the visualization method to show the spatial distribution of entire polymer series. The mass peaks included in polymer series were specified from the average mass spectrum of the entire MSI measurement region by using Kendrick mass defect analysis. The images of those mass peaks were extracted and the number average molecular weight (Mn ), the weight average molecular weight (Mw ) and dispersity (Đ) were calculated for each pixel. Finally, the spatial distribution of the polymer series was summarized to images using Mn , Mw and Đ as indices. The effects of the methods were investigated by (i) polymers with different mass distributions and (ii) polymers with different repeat units and end-groups. In both cases, the spatial distribution of specific polymer series including several dozens to hundreds of mass peaks was summarized into three images related to Mn , Mw and Đ, which are familiar indices in polymer analysis. The results are able to provide an overview of the spatial variation of each polymer more intuitively. The visualization of Mn , Mw and Đ will help provide an overview of the spatial distribution of polymer series combined with ion intensity distribution made by conventional methods. It can be also applied to other mass spectrometric imaging methods such as desorption electrospray ionization (DESI) or time-of-flight secondary ion mass spectrometry (TOF-SIMS).

MSPolyCalc: A web-based App for polymer mass spectrometry data interpretation. The case study of a pharmaceutical excipient.

In contrast to biological polymers, synthetic macromolecules consist of distributions of sizes, chemical compositions, functionalities and eventually architectures. The mass spectrum of a synthetic polymer may exhibit a tremendous number of signals. The availability of suitable IT tools to support interpretation is key. A web-based tool is presented: MSPolyCalc. It offers a set of functionalities, including the calculation of polymer distributions, molecular formulae and a match evaluation for peak assignment based on both mass and spectral accuracy (similarity score). The software was successfully tested with mass spectra exhibiting resolutions ranging from 10,000 to 240,000. The molecular characterization of a synthetic poly(ethylene glycol)-based excipient was achieved. MSPolyCalc allowed the discrimination of six polymer compositions of variable relative abundance. Secondary ionization adducts with very low intensity consisting of matrix-analyte clusters were also successfully identified. MSPolyCalc offers assisted data interpretation to target the needs of polymer chemists. It facilitates structure characterization, ionization adduct identification, and end-group determination together with visual result reporting.