Evaluation of automated synthesis for chain and step‐growth polymerizations: Can robots replace the chemists?

Rojas, Ramiro; Harris, Nicole K.; Piotrowska, Karolina; Kohn, Joachim

doi:10.1002/pola.23119

Cited by 42 publications

(40 citation statements)

References 22 publications

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“…The tyrosine-derived polycarbonate based co-polymer used for coating was synthesized at the New Jersey Center for Biomaterials according to previously published procedures (Rojas et al 2009; Schut et al 2007) from 3 monomers: desaminotyrosyl-tyrosine alkyl ethyl ester (DTE), desaminotyrosyl-tyrosine (DT), and low-molecular-weight poly(ethylene glycol) (PEG). The naming convention for this type of polymer is EXXYY(MW), meaning poly(DTE-co-XX%DT-co-YY%-PEGMW carbonate) where XX is the mole percent of DT, YY is the mole percent of the PEG and the MW is the average molecular weight of the PEG (Fig.…”

Section: Methodsmentioning

confidence: 99%

Coating flexible probes with an ultra fast degrading polymer to aid in tissue insertion

Wang

Singh

et al. 2015

Biomed Microdevices

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We report a fabrication process for coating neural probes with an ultrafast degrading polymer to create consistent and reproducible devices for neural tissue insertion. The rigid polymer coating acts as a probe insertion aid, but resorbs within hours post-implantation. Despite the feasibility for short term neural recordings from currently available neural prosthetic devices, most of these devices suffer from long term gliosis, which isolates the probes from adjacent neurons, increasing the recording impedance and stimulation threshold. The size and stiffness of implanted probes have been identified as critical factors that lead to this long term gliosis. Smaller, more flexible probes that match the mechanical properties of brain tissue could allow better long term integration by limiting the mechanical disruption of the surrounding tissue during and after probe insertion, while being flexible enough to deform with the tissue during brain movement. However, these small flexible probes inherently lack the mechanical strength to penetrate the brain on their own. In this work, we have developed a micromolding method for coating a non-functional miniaturized SU-8 probe with an ultrafast degrading tyrosine-derived polycarbonate (E5005(2K)). Coated, non-functionalized probes of varying dimensions were reproducibly fabricated with high yields. The polymer erosion/degradation profiles of the probes were characterized in vitro. The probes were also mechanically characterized in ex vivo brain tissue models by measuring buckling and insertion forces during probe insertion. The results demonstrate the ability to produce polymer coated probes of consistent quality for future in vivo use, for example to study the effects of different design parameters that may affect tissue response during long term chronic intra-cortical microelectrode neural recordings.

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Section: Methodsmentioning

confidence: 99%

Coating flexible probes with an ultra fast degrading polymer to aid in tissue insertion

Wang

Singh

et al. 2015

Biomed Microdevices

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“…[114,115,251] High throughput methods have been applied to synthesize libraries of methacrylate polymers (MAA, various oligo(ethylene glycol) methacrylates and copolymers of MAA with PEGMA, [108] MMA, DMAEMA and block and statistical copolymers, [114] and copolymers of DMAEMA with PEGMA [113] ) for evaluating the composition dependence of the lower critical solution temperature (LCST).…”

Section: Reaction Conditions (Initiator Temperature Pressure Solvementioning

confidence: 99%

Living Radical Polymerization by the RAFT Process - A Second Update

Moad¹,

Rizzardo²,

Thang³

2009

Aust. J. Chem.

905

720

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This paper provides a second update to the review of reversible deactivation radical polymerization achieved with thiocarbonylthio compounds (ZC(=S)SR) by a mechanism of reversible addition-fragmentation chain transfer (RAFT) that was published in June 2005 (Aust. J. Chem. 2005, 58, 379-410). The first update was published in November 2006 (Aust. J. Chem. 2006, 59, 669-692). This review cites over 500 papers that appeared during the period mid-2006 to mid-2009 covering various aspects of RAFT polymerization ranging from reagent synthesis and properties, kinetics and mechanism of polymerization, novel polymer syntheses and a diverse range of applications. Significant developments have occurred, particularly in the areas of novel RAFT agents, techniques for end-group removal and transformation, the production of micro/nanoparticles and modified surfaces, and biopolymer conjugates both for therapeutic and diagnostic applications.

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“…Polycarbonates such as poly(bisphenol A carbonate) and tyrosine derived polycarbonates, are commercially valuable materials that are efficiently synthesized using triphosgene [24] [25]. Due to its toxicity, it is crucial that all excess triphosgene be quenched prior to work up and precipitation of the polymer.…”

Section: Resultsmentioning

confidence: 99%

Simple, rapid, and highly sensitive detection of diphosgene and triphosgene by spectrophotometric methods

Joy

Anim-Danso

Kohn

2009

Talanta

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Methods for the detection and estimation of diphosgene and triphosgene are described. These compounds are widely used phosgene precursors which produce an intensely colored purple pentamethine oxonol dye when reacted with 1,3-dimethylbarbituric acid (DBA) and pyridine (or a pyridine derivative). Two quantitative methods are described, based on either UV absorbance or fluorescence of the oxonol dye. Detection limits are ~ 4 µmol/L by UV and <0.4 µmol/L by fluorescence. The third method is a test strip for the simple and rapid detection and semi-quantitative estimation of diphosgene and triphosgene, using a filter paper embedded with dimethylbarbituric acid and poly(4-vinylpyridine). Addition of a test solution to the paper causes a color change from white to light blue at low concentrations and to pink at higher concentrations of triphosgene. The test strip is useful for quick on-site detection of triphosgene and diphosgene in reaction mixtures. The test strip is easy to perform and provides clear signal readouts indicative of the presence of phosgene precursors. The utility of this method was demonstrated by the qualitative determination of residual triphosgene during the production of poly(Bisphenol A carbonate). Keywordstriphosgene; phosgene; spectrophotometry; spectrofluorimetry; test strip; poly(Bisphenol A carbonate)Phosgene and its safer derivatives -diphosgene and triphosgene -are industrially important chemicals used in the manufacture of polyurethanes [1] and polycarbonates [2] and in the synthesis of various active pharmaceutical ingredients. [3] This market sector generates approximately 8 million tons of products and the global demand for phosgene is about 5 million tons per year.[4] Phosgene is very corrosive and has a high acute toxicity if inhaled. The danger of inhalation poisoning is particularly grave, since phosgene can be lethal before its odor is recognizable. [5] Current methods for the detection of phosgene are predominantly electrochemical and spectrophotometric. [6,7] A cellulose tape impregnated with 4-nitrobenzylpyridine and benzylaniline has been developed for monitoring phosgene in air. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. They have shown that organic cyanates react with dimethylbarbituric acid in pyridine-water to produce an intensely colored purple oxonol dye. The mechanism of color formation is based on the nucleophilic reaction of pyridine with an activated electrophilic species. This reaction is also used for the detection and determination of HCN. NIH Public Access Author Manuscript[20] A similar reaction between phosg...

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Evaluation of automated synthesis for chain and step‐growth polymerizations: Can robots replace the chemists?

Cited by 42 publications

References 22 publications

Coating flexible probes with an ultra fast degrading polymer to aid in tissue insertion

Coating flexible probes with an ultra fast degrading polymer to aid in tissue insertion

Living Radical Polymerization by the RAFT Process - A Second Update

Simple, rapid, and highly sensitive detection of diphosgene and triphosgene by spectrophotometric methods

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