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Ruiz-Pérez L, Rizzello L, Wang J, Li N, Battaglia G, Pei Y. Polypyrrole and polyaniline nanocomposites with high photothermal conversion efficiency. Soft Matter 2020; 16:4569-4573. [PMID: 32373877 DOI: 10.1039/d0sm00306a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The simple and scalable synthesis of poly[2-(methacryloyloxy)ethyl phosphorylcholine] (PMPC)-coated conducting polymer (CP) nanocomposites is described. These functional nanocomposites exhibit tunable absorption in the near-infrared region with relatively high photothermal efficiencies. More importantly, their potential for bio-imaging and therapeutic treatment is proven by cellular uptake and cytotoxicity studies.
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Affiliation(s)
- Lorena Ruiz-Pérez
- Department of Chemistry, University College London, London, WC1H 0AJ, UK. and The EPSRC/JEOL Centre for Liquid Electron Microscopy, London, WC1H 0AJ, UK
| | - Loris Rizzello
- Department of Chemistry, University College London, London, WC1H 0AJ, UK.
| | - Jinping Wang
- Tianjin Key Laboratory of Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, 300072, P. R. China
| | - Nan Li
- Tianjin Key Laboratory of Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, 300072, P. R. China
| | - Giuseppe Battaglia
- Department of Chemistry, University College London, London, WC1H 0AJ, UK. and The EPSRC/JEOL Centre for Liquid Electron Microscopy, London, WC1H 0AJ, UK and Department of Chemical Engineering, University College London, London, UK
| | - Yiwen Pei
- Department of Chemistry, University College London, London, WC1H 0AJ, UK.
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Chen X, Lin Z, Feng Y, Tan H, Xu X, Luo J, Li J. Zwitterionic PMCP-Modified Polycaprolactone Surface for Tissue Engineering: Antifouling, Cell Adhesion Promotion, and Osteogenic Differentiation Properties. Small 2019; 15:e1903784. [PMID: 31448570 DOI: 10.1002/smll.201903784] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/11/2019] [Indexed: 06/10/2023]
Abstract
Biodegradable polycaprolactone (PCL) has been widely applied as a scaffold material in tissue engineering. However, the PCL surface is hydrophobic and adsorbs nonspecific proteins. Some traditional antifouling modifications using hydrophilic moieties have been successful but inhibit cell adhesion, which is not ideal for tissue engineering. The PCL surface is modified with bioinspired zwitterionic poly[2-(methacryloyloxy)ethyl choline phosphate] (PMCP) via surface-initiated atom transfer radical polymerization to improve cell adhesion through the unique interaction between choline phosphate (CP, on PMCP) and phosphate choline (PC, on cell membranes). The hydrophilicity of the PCL surface is significantly enhanced after surface modification. The PCL-PMCP surface reduces nonspecific protein adsorption (e.g., up to 91.7% for bovine serum albumin) due to the zwitterionic property of PMCP. The adhesion and proliferation of bone marrow mesenchymal stem cells on the modified surface is remarkably improved, and osteogenic differentiation signs are detected, even without adding any osteogenesis-inducing supplements. Moreover, the PCL-PMCP films are more stable at the early stage of degradation. Therefore, the PMCP-functionalized PCL surface promotes cell adhesion and osteogenic differentiation, with an antifouling background, and exhibits great potential in tissue engineering.
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Affiliation(s)
- Xingyu Chen
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
- College of Medicine, Southwest Jiaotong University, Chengdu, 610003, P. R. China
| | - Zaifu Lin
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Ying Feng
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Hong Tan
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Xinyuan Xu
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Jun Luo
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Jianshu Li
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
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Zhao Y, Deng Y, Tang Z, Jin Q, Ji J. Zwitterionic Reduction-Activated Supramolecular Prodrug Nanocarriers for Photodynamic Ablation of Cancer Cells. Langmuir 2019; 35:1919-1926. [PMID: 30204452 DOI: 10.1021/acs.langmuir.8b02745] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An adamantane-containing zwitterionic copolymer poly(2-(methacryloyloxy)ethyl phosphorylcholine)- co-poly(2-(methacryloyloxy)ethyl adamantane-1-carboxylate) (poly(MPC- co-MAda)) was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The hydrophobic photosensitizer chlorin e6 (Ce6) was conjugated to β-cyclodextrin (β-CD) by glutathione (GSH)-sensitive disulfide bonds. The Ce6 conjugated supramolecular prodrug nanocarriers were fabricated due to the host-guest interaction between adamantane and β-CD, which was confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The Ce6 conjugated prodrug nanocarriers showed reduction-responsive release of Ce6, which could result in the activation of Ce6. The generation of cytotoxic reactive oxygen species (ROS) was significantly enhanced due to the activation of Ce6. In additiona, the Ce6 conjugated prodrug nanocarriers could effectively inhibit the proliferation of cancer cells upon light irradiation.
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Affiliation(s)
- Yiming Zhao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Yongyan Deng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Zhe Tang
- Department of Surgery, second Affiliated Hospital, School of Medicine , Zhejiang University , Hangzhou 310009 , China
| | - Qiao Jin
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Jian Ji
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
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Ma MQ, Zhang C, Chen TT, Yang J, Wang JJ, Ji J, Xu ZK. Bioinspired Polydopamine/Polyzwitterion Coatings for Underwater Anti-Oil and -Freezing Surfaces. Langmuir 2019; 35:1895-1901. [PMID: 30145900 DOI: 10.1021/acs.langmuir.8b02320] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Zwitterionic polymers are continually suggested as promising alternatives to tune the surface/interface properties of materials in many fields because of their unique molecular structures. Tremendous efforts have been devoted to immobilizing zwitterionic polymers (polyzwitterions, PZIs) on the material surfaces. However, these efforts usually suffer from cumbersome and time-consuming procedures. Herein we report a one-step strategy to facilely achieve the bioinspired polydopamine/polyzwitterion (PDA/PZI) coatings on various substrates. It requires only 30 min to form PDA/PZI coatings by mixing oxidant, dopamine, and zwitterionic monomers, including carboxybetaine methacrylate (CBMA), sulfobetaine methacrylate (SBMA), and 2-methacryloxyethyl phosphorylcholine (MPC). These bioinspired coatings display multifunctional properties such as underwater antioil-adhesion and antifreezing thanks to their high hydrophilicity and underwater superoleophobicity. The coatings even show the antiadhesion property for crude oil with high viscosity. Therefore, the PDA/PZI-coated meshes are efficient for separating both light oil and crude oil from oil/water mixtures. All these results demonstrate that the one-step strategy is a facile approach to design and exploit the bioinspired PDA/PZI coatings for diverse applications.
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Affiliation(s)
- Meng-Qi Ma
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Chao Zhang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Ting-Ting Chen
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Jing Yang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Jian-Jun Wang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Jian Ji
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Zhi-Kang Xu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China
- Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
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Han L, Xiang L, Zhang J, Chen J, Liu J, Yan B, Zeng H. Biomimetic Lubrication and Surface Interactions of Dopamine-Assisted Zwitterionic Polyelectrolyte Coatings. Langmuir 2018; 34:11593-11601. [PMID: 30156852 DOI: 10.1021/acs.langmuir.8b02473] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A bioinspired zwitterionic polyelectrolyte coating with excellent hydration ability has been regarded as a promising lubricating candidate for modifying artificial joint cartilage surface. In physiological fluids, the ubiquitous proteins play an important role in achieving outstanding boundary lubrication; however, a comprehensive understanding of the hydration lubrication between polyelectrolyte coatings and proteins still remains unclear. In this work, a facile fabrication of ultrasmooth polyelectrolyte coatings was developed via codeposition of synthesized poly(dopamine methacrylamide- co-2-methacryloyloxyethyl phosphorylcholine) (P(DMA- co-MPC)) and dopamine (DA) in a mild condition. Upon optimization of the feeding ratio of P(DMA- co-MPC) and DA, the as-fabricated PDA/P(DMA- co-MPC) coatings exhibit excellent lubricating properties when sliding with each other (friction coefficient μ = 0.036 ± 0.002, ∼2.8 MPa), as well as sliding with a model protein (bovine serum albumin (BSA)) layer (μ = 0.041 ± 0.005, ∼4.8 MPa) in phosphate-buffered saline (PBS, pH 7.4). Intriguingly, the lubrication in both systems shows Amontons-like behaviors: the friction is directly proportional to the applied load but independent of the shear velocity. Moreover, the PDA/P(DMA- co-MPC) coatings could resist the protein fouling (i.e., BSA) in PBS, which is crucial to prevent the surfaces from being contaminated when applied in biological media, thus maintaining their lubricating properties. Our results provide a versatile approach for facilely fabricating polyelectrolyte coatings with superior lubrication properties to both polyelectrolyte coatings and protein surfaces, with useful implications into the development of novel lubricating coatings for bioengineering applications (e.g., artificial joints).
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Affiliation(s)
- Linbo Han
- College of Health Science and Environmental Engineering , Shenzhen Technology University , Shenzhen 518118 , China
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
| | - Li Xiang
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
| | - Jiawen Zhang
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
| | - Jingsi Chen
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
| | - Jifang Liu
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
- The Fifth Affiliated Hospital , Guangzhou Medical University , Guangzhou , Guangdong 510700 , China
| | - Bin Yan
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
- College of Light Industry, Textile & Food Engineering, Sichuan University , Chengdu 610065 , China
| | - Hongbo Zeng
- College of Health Science and Environmental Engineering , Shenzhen Technology University , Shenzhen 518118 , China
- Chemical and Materials Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
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Wang J, Song Y, Sun P, An Y, Zhang Z, Shi L. Reversible Interactions of Proteins with Mixed Shell Polymeric Micelles: Tuning the Surface Hydrophobic/Hydrophilic Balance toward Efficient Artificial Chaperones. Langmuir 2016; 32:2737-2749. [PMID: 26948309 DOI: 10.1021/acs.langmuir.6b00356] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Molecular chaperones can elegantly fine-tune its hydrophobic/hydrophilic balance to assist a broad spectrum of nascent polypeptide chains to fold properly. Such precious property is difficult to be achieved by chaperone mimicking materials due to limited control of their surface characteristics that dictate interactions with unfolded protein intermediates. Mixed shell polymeric micelles (MSPMs), which consist of two kinds of dissimilar polymeric chains in the micellar shell, offer a convenient way to fine-tune surface properties of polymeric nanoparticles. In the current work, we have fabricated ca. 30 kinds of MSPMs with finely tunable hydrophilic/hydrophobic surface properties. We investigated the respective roles of thermosensitive and hydrophilic polymeric chains in the thermodenaturation protection of proteins down to the molecular structure. Although the three kinds of thermosensitive polymers investigated herein can form collapsed hydrophobic domains on the micellar surface, we found distinct capability to capture and release unfolded protein intermediates, due to their respective affinity for proteins. Meanwhile, in terms of the hydrophilic polymeric chains in the micellar shell, poly(ethylene glycol) (PEG) excels in assisting unfolded protein intermediates to refold properly via interacting with the refolding intermediates, resulting in enhanced chaperone efficiency. However, another hydrophilic polymer-poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) severely deteriorates the chaperone efficiency of MSPMs, due to its protein-resistant properties. Judicious combination of thermosensitive and hydrophilic chains in the micellar shell lead to MSPM-based artificial chaperones with optimal efficacy.
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Affiliation(s)
- Jianzu Wang
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University , Tianjin 300071, P.R. China
| | - Yiqing Song
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University , Tianjin 300071, P.R. China
| | - Pingchuan Sun
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University , Tianjin 300071, P.R. China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, China
| | - Yingli An
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University , Tianjin 300071, P.R. China
| | - Zhenkun Zhang
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University , Tianjin 300071, P.R. China
| | - Linqi Shi
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University , Tianjin 300071, P.R. China
- State Key Laboratory of Medicinal Chemical Biology, Nankai University , Tianjin 300071, P.R. China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, China
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Wiarachai O, Vilaivan T, Iwasaki Y, Hoven VP. Clickable and Antifouling Platform of Poly[(propargyl methacrylate)-ran-(2-methacryloyloxyethyl phosphorylcholine)] for Biosensing Applications. Langmuir 2016; 32:1184-1194. [PMID: 26695478 DOI: 10.1021/acs.langmuir.5b02727] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A functional copolymer platform, namely, poly[(propargyl methacrylate)-ran-(2-methacryloyloxyethyl phosphorylcholine)] (PPgMAMPC), was synthesized by reversible addition-fragmentation chain-transfer polymerization. In principle, the alkyne moiety of propargyl methacrylate (PgMA) should serve as an active site for binding azide-containing molecules via a click reaction, i.e., Cu-catalyzed azide/alkyne cycloaddition (CuAAC), and 2-methacryloyloxyethyl phosphorylcholine (MPC), the hydrophilic monomeric unit, should enable the copolymer to suppress nonspecific adsorption. The copolymers were characterized using Fourier transform infrared (FTIR) and (1)H NMR spectroscopies. Thiol-terminated, PPgMAMPC-SH, obtained by aminolysis of PPgMAMPC, was immobilized on a gold-coated substrate using a "grafting to" approach via self-assembly. Azide-containing species, namely, biotin and peptide nucleic acid (PNA), were then immobilized on the alkyne-containing copolymeric platform via CuAAC. The potential use of surface-attached PPgMAMPC in biosensing applications was shown by detection of specific target molecules, i.e., streptavidin (SA) and DNA, by the developed sensing platform using a surface plasmon resonance technique. The copolymer composition strongly influenced the performance of the developed sensing platform in terms of signal-to-noise ratio in the case of the biotin-SA system and hybridization efficiency and mismatch discrimination for the PNA-DNA system.
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Affiliation(s)
| | | | - Yasuhiko Iwasaki
- Faculty of Chemistry, Materials and Bioengineering, Kansai University , 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan
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Korb ML, Warram JM, Grudzinski J, Weichert J, Jeffery J, Rosenthal EL. Breast cancer imaging using the near-infrared fluorescent agent, CLR1502. Mol Imaging 2015; 13. [PMID: 25743270 DOI: 10.2310/7290.2014.00040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Positive margins after breast conservation surgery represent a significant problem in the treatment of breast cancer. The near-infrared fluorescence agent CLR1502 (Cellectar Biosciences, Madison, WI) was studied in a preclinical breast cancer model to determine imaging properties and ability to detect small islands of malignancy. Nude mice bearing human breast cancer flank xenografts were given a systemic injection of CLR1502, and imaging was performed using LUNA (Novadaq Technologies Inc., Richmond, BC) and Pearl Impulse (LI-COR Biosciences, Lincoln, NE) devices. Normal tissues were examined for fluorescence signal, and conventional and fluorescence histology was performed using the Odyssey scanner. Peak tumor to background ratio occurred 2 days after injection with CLR1502. The smallest amount of tumor that was imaged and detected using these devices was 1.9 mg, equivalent to 1.9 × 10⁶ cells. The highest fluorescence signal was seen in tumor and normal lymph node tissue, and the lowest fluorescence signal was seen in muscle and plasma. Human breast cancer tumors can be imaged in vivo with multiple optical imaging platforms using CLR1502. This pilot study supports further investigations of this fluorescent agent for improving surgical resection of malignancies, with the goal of eventual clinical translation.
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Affiliation(s)
- H Eibl
- Max-Planck-Institut für biophysikalische Chemie, Göttingen, FRG
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Fang J, Ye SH, Shankarraman V, Huang Y, Mo X, Wagner WR. Biodegradable poly(ester urethane)urea elastomers with variable amino content for subsequent functionalization with phosphorylcholine. Acta Biomater 2014; 10:4639-4649. [PMID: 25132273 DOI: 10.1016/j.actbio.2014.08.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/18/2014] [Accepted: 08/05/2014] [Indexed: 12/01/2022]
Abstract
While surface modification is well suited for imparting biomaterials with specific functionality for favorable cell interactions, the modification of degradable polymers would be expected to provide only temporary benefit. Bulk modification by incorporating pendant reactive groups for subsequent functionalization of biodegradable polymers would provide a more enduring approach. Towards this end, a series of biodegradable poly(ester urethane)urea elastomers with variable amino content (PEUU-NH2 polymers) were developed. Carboxylated phosphorycholine was synthesized and conjugated to the PEUU-NH2 polymers for subsequent bulk functionalization to generate PEUU-PC polymers. Synthesis was verified by proton nuclear magnetic resonance, X-ray photoelectron spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The impact of amine incorporation and phosphorylcholine conjugation was shown on mechanical, thermal and degradation properties. Water absorption increased with increasing amine content, and further with PC conjugation. In wet conditions, tensile strength and initial modulus generally decreased with increasing hydrophilicity, but remained in the range of 5-30 MPa and 10-20 MPa, respectively. PC conjugation was associated with significantly reduced platelet adhesion in blood contact testing and the inhibition of rat vascular smooth muscle cell proliferation. These biodegradable PEUU-PC elastomers offer attractive properties for applications as non-thrombogenic, biodegradable coatings and for blood-contacting scaffold applications. Further, the PEUU-NH2 base polymers offer the potential to have multiple types of biofunctional groups conjugated onto the backbone to address a variety of design objectives.
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Affiliation(s)
- Jun Fang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Sang-Ho Ye
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Venkat Shankarraman
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Yixian Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Xiumei Mo
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China; College of Chemistry and Chemical Engineering and Biological Engineering, Donghua University, Shanghai 201620, China
| | - William R Wagner
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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Drescher S, Lechner BD, Garamus VM, Almásy L, Meister A, Blume A. The headgroup (a)symmetry strongly determines the aggregation behavior of single-chain phenylene-modified bolalipids and their miscibility with classical phospholipids. Langmuir 2014; 30:9273-9284. [PMID: 25025213 DOI: 10.1021/la501160s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In the present work, we describe the synthesis of two single-chain phenylene-modified bolalipids, namely PC-C17pPhC17-PC and PC-C17pPhC17-OH, with either symmetrical (phosphocholine) or asymmetrical (phosphocholine and hydroxyl) headgroups using a Sonogashira cross-coupling reaction as key step. The temperature-dependent aggregation behavior of both bolalipids in aqueous suspension was studied using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, small angle neutron scattering (SANS), and X-ray scattering. We show that different headgroup symmetries lead to a change in the aggregation behavior: Whereas PC-C17pPhC17-PC forms nanofibers with a diameter of 5.7 nm that transform into small ellipsoidal micelles at 23 °C, the PC-C17pPhC17-OH self-assembles into lamellae with bolalipid molecules in an antiparallel orientation up to high temperatures. Furthermore, the mixing behavior of both bolalipids with bilayer-forming phospholipids (DPPC and DSPC) was studied by means of DSC and TEM. The aim was to stabilize bilayer membranes formed of phospholipids in order to improve these mixed lipid vesicles for drug delivery purposes. We show that the symmetrical PC-C17pPhC17-PC is miscible with DPPC and DSPC; however, closed lipid vesicles are not observed, and elongated micelles and bilayer fragments are found instead. In contrast, the asymmetrical PC-C17pPhC17-OH shows no miscibility with phospholipids at all.
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Affiliation(s)
- Simon Drescher
- Institute of Pharmacy, Martin-Luther-Universitaet (MLU) Halle-Wittenberg , Wolfgang-Langenbeck-Strasse 4, 06120 Halle (Saale), Germany
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Warren NJ, Muise C, Stephens A, Armes SP, Lewis AL. Near-monodisperse poly(2-(methacryloyloxy)ethyl phosphorylcholine)-based macromonomers prepared by atom transfer radical polymerization and thiol-ene click chemistry: novel reactive steric stabilizers for aqueous emulsion polymerization. Langmuir 2012; 28:2928-2936. [PMID: 22191694 DOI: 10.1021/la204083z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) macromonomers have been prepared by the atom transfer radical polymerization (ATRP) of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) using a bifunctional disulfide-based initiator. To attach a terminal polymerizable methacrylate group, the central disulfide bond was cleaved and the resulting thiols were conjugated to 3-(acryloyloxy)-2-hydroxypropyl methacrylate using tris(2-carboxyethyl)phosphine (TCEP) in water. Here TCEP serves as both the disulfide cleavage agent and also the catalyst for the subsequent Michael addition, which is highly selective for the acrylate group. The resulting methacrylate-terminated macromonomers were used as a reactive steric stabilizer for the aqueous emulsion polymerization of styrene, yielding near-monodisperse PMPC-stabilized polystyrene (PS) latexes of around 100-200 nm in diameter. As a comparison, the disulfide-containing PMPC homopolymer precursor and the intermediate thiol-functional PMPC homopolymer (PMPC-SH) were also evaluated as potential steric stabilizers. Interestingly, near-monodisperse latexes were also obtained in each case. These three sterically-stabilized latexes, prepared using either PMPC macromonomer, disulfide-based PMPC homopolymer, or PMPC-SH homopolymer as a reactive steric stabilizer, remained colloidally stable after both freeze-thaw experiments and the addition of an electrolyte, indicating that a coronal layer of PMPC chains prevented flocculation in each case. In contrast, both a charge-stabilized PS latex prepared in the absence of any steric stabilizer and a PS latex prepared in the presence of a nonfunctional PMPC homopolymer exhibited very poor colloidal stability when subjected to a freeze-thaw cycle or the addition of an electrolyte, as expected.
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Affiliation(s)
- Nicholas J Warren
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
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Edmondson S, Nguyen NT, Lewis AL, Armes SP. Co-nonsolvency effects for surface-initiated poly(2-(methacryloyloxy)ethyl phosphorylcholine) brushes in alcohol/water mixtures. Langmuir 2010; 26:7216-26. [PMID: 20380474 DOI: 10.1021/la904346j] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Surface-initiated atom transfer radical polymerization (SI-ATRP) has been used to grow brushes of poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) from silicon wafers using a polyelectrolytic macroinitiator on planar silicon wafers. Film thicknesses of up to 450 nm were possible within 21 h, and the effect of adding activator and deactivator species on the brush growth rate was studied. The solvation of PMPC brushes in mixed alcohol/water solvents was investigated using in situ ellipsometry. Co-nonsolvency (a re-entrant swelling transition) behavior was observed in water/ethanol binary mixtures; that is, the PMPC brushes were highly swollen in either pure ethanol or water but became deswollen at specific ethanol-rich solvent compositions. A similar effect was obtained with water/2-propanol mixtures, except that in this case pure 2-propanol was not a particularly good solvent for the PMPC chains. However, co-nonsolvency was not observed for water/methanol binary mixtures, since the brushes remained well swollen at all solvent compositions. This is consistent with prior reports of co-nonsolvency effects in both PMPC gels and linear PMPC chains. However, this is the first report of this phenomenon for PMPC brushes and one of the first examples of co-nonsolvency observed for any polymer brush system. A direct comparison of brush and gel swelling reveals an approximate power-law relationship between the equilibrium volumes of these two systems at various solvent compositions, which is interpreted by treating the brush layer as a surface-attached gel. We believe this to be the first quantitative comparison of brush and gel swelling using the same polymer under the same conditions. The kinetics of the PMPC brush response to adjustment of the alcohol/water composition is relatively fast, with the brush volume change occurring on time scales of less than 1 min as judged by in situ ellipsometry.
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Affiliation(s)
- Steve Edmondson
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom.
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Ahmad H, Dupin D, Armes SP, Lewis AL. Synthesis of biocompatible sterically-stabilized poly(2-(methacryloyloxy)ethyl phosphorylcholine) latexes via dispersion polymerization in alcohol/water mixtures. Langmuir 2009; 25:11442-11449. [PMID: 19588940 DOI: 10.1021/la901631a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) is soluble in either 2-propanol or water but becomes insoluble in certain alcohol-rich 2-propanol/water mixtures. We have exploited this unusual cononsolvency behavior in order to prepare new biocompatible sterically stabilized PMPC latexes via nonaqueous dispersion polymerization in 2-propanol/water mixtures. All polymerizations were conducted in the presence of monomethoxy-capped poly(ethylene glycol) methacrylate (PEGMA) as a reactive stabilizer, with some formulations including ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Under optimized conditions, unimodal size distributions could be obtained with a mean latex diameter of approximately 1 microm, as judged by laser diffraction and DLS. The mean latex diameter depended on both the PEGMA and initiator concentration but was almost independent of the cross-linking density. Smaller PMPC latexes were obtained by increasing the alcohol content of the dispersion medium. On dilution with water, these latexes acquired microgel character. The microgel solution viscosity was insensitive to added salt due to the so-called "antipolyelectrolyte" effect, which is characteristic of polyzwitterions. Finally, copolymerization of MPC with a fluorescein-based methacrylic comonomer produced fluorescently labeled PMPC latexes, which may have potential biomedical applications.
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Affiliation(s)
- Hasan Ahmad
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK
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Du J, Armes SP. Preparation of biocompatible zwitterionic block copolymer vesicles by direct dissolution in water and subsequent silicification within their membranes. Langmuir 2009; 25:9564-9570. [PMID: 19572508 DOI: 10.1021/la900834z] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The facile preparation of block copolymer vesicles in pure water and their subsequent stabilization by sol-gel chemistry within the vesicle membrane is described. An amphiphilic biocompatible zwitterionic diblock copolymer, poly(epsilon-caprolactone)-block-poly[2-(methacryloyloxy)ethyl phosphorylcholine], PCL-b-PMPC, was synthesized by (i) ring-opening polymerization of epsilon-caprolactone, (ii) end-group modification by esterification, and (iii) atom transfer radical polymerization (ATRP) of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC). Unusually, block copolymer vesicles were formed instantly upon adding dried copolymer powder into hot water without using organic cosolvents, pH adjustment, or even stirring. This protocol is much more convenient than previously reported methods such as solvent-switching and film rehydration. The PCL vesicle membrane is moderately hydrophobic and fully biodegradable. The highly biocompatible PMPC chains are expressed on both the exterior and interior surface of the membrane. These vesicles can be stabilized by aqueous sol-gel chemistry within the hydrophobic PCL vesicle membrane by using tetramethyl orthosilicate (TMOS) as the silica precursor in the absence of any external catalyst. The water-immiscible TMOS precursor is initially solubilized within the hydrophobic membrane prior to its in situ transformation into silica. The vesicles were characterized by 1H NMR spectroscopy, atomic force microscopy, transmission electron microscopy, and dynamic light scattering.
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Affiliation(s)
- Jianzhong Du
- Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom.
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Drescher S, Meister A, Blume A, Karlsson G, Almgren M, Dobner B. General synthesis and aggregation behaviour of a series of single-chain 1,omega-bis(phosphocholines). Chemistry 2007; 13:5300-7. [PMID: 17385202 DOI: 10.1002/chem.200601866] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The synthesis and physicochemical characterisation of a series of polymethylene-1,omega-bis(phosphocholines) with even-numbered chain lengths between 22 and 32 carbon atoms is described. Two new synthetic strategies for the preparation of long-chain 1,omega-diols as hydrocarbon building blocks are presented. The temperature-dependent self-assembly of the single-chain bolaamphiphiles was investigated by cryo transmission electron microscopy (cryo-TEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR).
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Affiliation(s)
- Simon Drescher
- Institute of Pharmacy, MLU Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, 06120 Halle/Saale, Germany
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Kyomoto M, Moro T, Konno T, Takadama H, Kawaguchi H, Takatori Y, Nakamura K, Yamawaki N, Ishihara K. Effects of photo-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on physical properties of cross-linked polyethylene in artificial hip joints. J Mater Sci Mater Med 2007; 18:1809-15. [PMID: 17483881 DOI: 10.1007/s10856-007-3063-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 05/31/2006] [Indexed: 05/15/2023]
Abstract
Osteolysis caused by wear particles from polyethylene in the artificial hip joints is a serious issue. We have used photo-induced radical graft polymerization to graft 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer onto the surface of cross-linked polyethylene (CLPE-g-MPC) in order to reduce friction and wear at the bearing surface of the joint. The physical and mechanical properties of CLPE and CLPE-g-MPC were not significantly different, expect that the friction coefficient of untreated CLPE cups was 0.0075, compared with 0.0009 for CLPE-g-MPC cup, an 88% reduction. After 3.0 x 10(6) cycles in the hip joint simulator test, we could not observe any wear of CLPE-g-MPC cups. We concluded that the advantage of photo-induced radical graft polymerization technique was that the grafted MPC polymer gave a high lubricity only on the surface and has no effect on the bulk properties of the CLPE substrate.
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Affiliation(s)
- Masayuki Kyomoto
- Research and Development Corporate Division, Japan Medical Materials Corporation, Uemura Nissei Bldg 9F, 3-3-31 Miyahara, Osaka, Japan.
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18
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Affiliation(s)
- Chengming Li
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK
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Kyomoto M, Moro T, Konno T, Takadama H, Yamawaki N, Kawaguchi H, Takatori Y, Nakamura K, Ishihara K. Enhanced wear resistance of modified cross-linked polyethylene by grafting with poly(2-methacryloyloxyethyl phosphorylcholine). J Biomed Mater Res A 2007; 82:10-7. [PMID: 17265442 DOI: 10.1002/jbm.a.31134] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We developed a cross-linked polyethylene (CLPE) modified with a phospholipid polymer in order to address the serious problem of osteolysis caused by wear particles derived from the polyethylene components of artificial hip joints. Our goal of preventing aseptic loosening could be achieved by avoiding any formation of CLPE wear particles or suppressing the activation of cell systems by the wear particles. We investigated the surface and wear resistance properties of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer grafted onto the surface of CLPE (CLPE-g-MPC). The relative density of MPC polymer chains was determined by the P-O group index. Generally, polymerization times correspond to the number of polymer chains in radical polymerization. After 3.0 x 10(6) cycles in a hip joint simulator test, the steady wear rates of the untreated CLPE and CLPE-g-MPC cups with a low P-O group index were as high as 4 mg/10(6) cycles; those of the CLPE-g-MPC cups with high P-O group indexes, that is, 0.46 and 0.48, markedly decreased to -1.12 and 0.16 mg/10(6) cycles, respectively. Therefore, the grafting of an MPC polymer with high density would be essential in order to maintain the long-term wear resistance of CLPE-g-MPC as an orthopedic bearing material.
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Affiliation(s)
- Masayuki Kyomoto
- Research and Development Corporate Division, Japan Medical Materials Corporation, Osaka, Japan.
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20
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Yuan JJ, Armes SP, Takabayashi Y, Prassides K, Leite CAP, Galembeck F, Lewis AL. Synthesis of biocompatible poly[2-(methacryloyloxy)ethyl phosphorylcholine]-coated magnetite nanoparticles. Langmuir 2006; 22:10989-93. [PMID: 17154575 DOI: 10.1021/la061834j] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A well-defined, double-hydrophilic diblock copolymer comprising poly[2-(methacryloyloxy)ethyl phosphorylcholine]-block-(glycerol monomethacrylate) (PMPC30-PGMA30, where the numbers represent the average degrees of polymerization for each block) was evaluated for the synthesis of colloidally stable ultrafine magnetite sols. Sterically stabilized paramagnetic sols were prepared in aqueous solution by chemical coprecipitation of ferric and ferrous salts in the presence of this block copolymer. The PMPC30-PGMA30-stabilized magnetite sol had a mean transmission electron microscopy (TEM) diameter of 9.4 +/- 1.7 nm and a mean hydrodynamic diameter of 34 nm. This sol exhibited improved colloidal stability with respect to long-term storage and pH variation compared with magnetite sols prepared in the presence of alternative water-soluble homopolymers and diblock copolymers. Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry, electron spectroscopy imaging (ESI), and zeta potential studies indicate that the PMPC30-PGMA30 diblock copolymer was adsorbed onto the surface of the sol via the PGMA30 block, with the PMPC30 chains acting as the stabilizing block. Such sterically stabilized sols are expected to be improved contrast agents for magnetic resonance imaging (MRI) applications.
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Affiliation(s)
- J-J Yuan
- Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
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21
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Yuan JJ, Schmid A, Armes SP, Lewis AL. Facile synthesis of highly biocompatible poly(2-(methacryloyloxy)ethyl phosphorylcholine)-coated gold nanoparticles in aqueous solution. Langmuir 2006; 22:11022-7. [PMID: 17154580 DOI: 10.1021/la0616350] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Diblock copolymers comprising a highly biocompatible poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) block and a poly(2-(dimethylamino)ethyl methacrylate) (PDMA) block were evaluated for the synthesis of sterically stabilized gold nanoparticles in aqueous solution. The PDMA block becomes partially protonated on addition of HAuCl4, and the remaining nonprotonated tertiary amine groups reduce the AuCl4- counterion to zerovalent gold in situ. This approach results in the adsorption of the PDMA block onto the gold nanoparticle surface while the PMPC chains serve as a stabilizing block, producing highly biocompatible gold sols in aqueous solution at ambient temperature without any external reducing agent. The size and shape of gold nanoparticles could be readily controlled by tuning synthesis parameters such as the block composition and the relative and absolute concentrations of the PMPC-PDMA diblock copolymer and HAuCl4. These highly biocompatible gold sols have potential biomedical applications.
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Affiliation(s)
- Jian-Jun Yuan
- Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
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Gutteridge WE. TDR collaboration with the pharmaceutical industry. Trans R Soc Trop Med Hyg 2006; 100 Suppl 1:S21-5. [PMID: 16730039 DOI: 10.1016/j.trstmh.2006.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Revised: 01/23/2006] [Accepted: 02/20/2006] [Indexed: 10/24/2022] Open
Abstract
TDR's research programme was initiated in 1976 at the same time that the pharmaceutical industry began to withdraw from the discovery and development of new drugs for tropical diseases. TDR collaborated with the industry right from the start, its prime objective initially being to ensure that candidate drugs already in the development pipeline, such as praziquantel, mefloquine, ivermectin, halofantrine and atovaquone/proguanil, were not shelved. It became clear during the 1980s that once candidate drugs in these existing pipelines had been processed, that would be it. TDR therefore developed a number of other ways for collaboration, including testing compounds already in development in companies for other therapeutic areas. One candidate identified in this way was an oral formulation of miltefosine, in development in Asta Medica for an antitumour indication. A joint Asta Medica (later Zentaris)/TDR development project was agreed, and despite its fair share of traumas during the development process, miltefosine is now registered for the treatment of visceral leishmaniasis in India, Germany and Colombia. This example of a successful TDR/pharmaceutical industry collaboration lives on in the various Public Private Partnerships such as the new Medicines for Malaria Venture that TDR helped to spawn.
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Acharya HP, Kobayashi Y. Total synthesis of 2-(5,6-epoxyisoprostane A2)phosphorylcholine and elucidation of the relative configuration of the isoprostane moiety. Angew Chem Int Ed Engl 2006; 44:3481-4. [PMID: 15861439 DOI: 10.1002/anie.200500534] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hukum P Acharya
- Department of Biomolecular Engineering, Tokyo Institute of Technology, Box B-52, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
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Hornillos V, Saugar JM, de la Torre BG, Andreu D, Rivas L, Acuña AU, Amat-Guerri F. Synthesis of 16-mercaptohexadecylphosphocholine, a miltefosine analog with leishmanicidal activity. Bioorg Med Chem Lett 2006; 16:5190-3. [PMID: 16870434 DOI: 10.1016/j.bmcl.2006.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 07/05/2006] [Accepted: 07/05/2006] [Indexed: 11/20/2022]
Abstract
The alkylphosphocholine miltefosine (n-hexadecylphosphocholine, MT) has been introduced recently as a very effective drug for the oral treatment of human leishmaniasis. However, the parasiticidal mechanism of MT at a molecular level is far from being understood. Here we report the synthesis and biological characterization of 16-mercaptohexadecylphosphocholine, a thiol analog of MT which was designed to facilitate the search of MT interacting targets within the parasite by a variety of analytical methods. This analog presents the same leishmanicidal effect as the parent drug against Leishmania donovani promastigotes and Leishmania pifanoi axenic amastigotes, and has been used to develop an affinity chromatography method to attempt the isolation of putative Leishmania proteins that bind to the phosphocholine part of the molecule.
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Affiliation(s)
- Valentín Hornillos
- Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
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Goda T, Konno T, Takai M, Moro T, Ishihara K. Biomimetic phosphorylcholine polymer grafting from polydimethylsiloxane surface using photo-induced polymerization. Biomaterials 2006; 27:5151-60. [PMID: 16797692 DOI: 10.1016/j.biomaterials.2006.05.046] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 05/29/2006] [Indexed: 11/25/2022]
Abstract
The biomimetic synthetic phospholipid polymer containing a phosphorylcholine group, 2-methacryloyloxyethyl phosphorylcholine (MPC), has improved the surface property of biomaterials. Both hydrophilic and anti-biofouling surfaces were prepared on polydimethylsiloxane (PDMS) with MPC grafted by surface-initiated photo-induced radical polymerization. Benzophenone was used as the photoinitiator. The quantity of the adsorbed initiator on PDMS was determined by UV absorption and ellipsometry. The poly(MPC)-grafted PDMS surfaces were characterized by XPS, ATR-FTIR and static water contact angle (SCA) measurements. The SCA on PDMS decreased from 115 degrees to 25 degrees after the poly(MPC) grafting. The in vitro single protein adsorption on the poly(MPC)-grafted PDMS decreased 50-75% compared to the unmodified PDMS. The surface friction of the poly(MPC)-grafted PDMS was lower than the unmodified PDMS under wet conditions. The oxygen permeability of the poly(MPC)-grafted PDMS was as high as the unmodified PDMS. The tensile property of PDMS was maintained at about 90% of the ultimate stress and strain after the poly(MPC) grafting. The surface-modified PDMS is expected to be a novel medical elastomer which possesses an excellent surface hydrophilicity, anti-biofouling property, oxygen permeability and tensile property.
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Affiliation(s)
- Tatsuro Goda
- Department of Materials Engineering, School of Engineering and Center for NanoBio Integration, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Gajate C, Mollinedo F. Edelfosine and perifosine induce selective apoptosis in multiple myeloma by recruitment of death receptors and downstream signaling molecules into lipid rafts. Blood 2006; 109:711-9. [PMID: 17003375 DOI: 10.1182/blood-2006-04-016824] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Multiple myeloma (MM) is an incurable B-cell malignancy, requiring new therapeutic strategies. We have found that synthetic alkyl-lysophospholipids (ALPs) edelfosine and perifosine induced apoptosis in MM cell lines and patient MM cells, whereas normal B and T lymphocytes were spared. ALPs induced recruitment of Fas/CD95 death receptor, Fas-associated death domain-containing protein, and procaspase-8 into lipid rafts, leading to the formation of the death-inducing signaling complex (DISC) and apoptosis. TNF-related apoptosis-inducing ligand receptor-1/death receptor 4 (TRAIL-R1/DR4) and TRAIL-R2/DR5, as well as Bid, were also recruited into lipid rafts, linking death receptor and mitochondrial signaling pathways. ALPs induced mitochondrial cytochrome c release. Bcl-X(L) overexpression prevented cytochrome c release and apoptosis. A Fas/CD95-deficient MM subline expressing DR4 and DR5 was resistant to edelfosine. Fas/CD95 retrovirus transduction bestowed edelfosine sensitivity in these cells. A Fas/CD95 mutant lacking part of the intracellular domain was ineffective. Lipid raft disruption prevented ALP-induced Fas/CD95 clustering, DISC formation, and apoptosis. ALP-induced apoptosis was Fas/CD95 ligand (FasL/CD95L) independent. ALP-induced recruitment of death receptors in lipid rafts potentiated MM cell killing by FasL/CD95L and TRAIL. These data uncover a novel lipid raft-mediated therapy in MM involving concentration of death receptors in membrane rafts, with Fas/CD95 playing a major role in ALP-mediated apoptosis.
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Affiliation(s)
- Consuelo Gajate
- Unidad de Investigación, Hospital Universitario de Salamanca, Spain
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27
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Pinchuk AN, Rampy MA, Longino MA, Skinner RWS, Gross MD, Weichert JP, Counsell RE. Synthesis and structure-activity relationship effects on the tumor avidity of radioiodinated phospholipid ether analogues. J Med Chem 2006; 49:2155-65. [PMID: 16570911 DOI: 10.1021/jm050252g] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Radioiodinated phospholipid ether analogues have shown a remarkable ability to selectively accumulate in a variety of human and animal tumors in xenograft and spontaneous tumor rodent models. It is believed that this tumor avidity arises as a consequence of metabolic differences between tumor and corresponding normal tissues. The results of this study indicate that one factor in the tumor retention of these compounds in tumors is the length of the alkyl chain that determines their hydrophobic properties. Decreasing the chain length from C12 to C7 resulted in little or no tumor accumulation and rapid clearance of the compound in tumor-bearing rats within 24 h of administration. Increasing the chain length had the opposite effect, with the C15 and C18 analogues displaying delayed plasma clearance and enhanced tumor uptake and retention in tumor-bearing rats. Tumor uptake displayed by propanediol analogues NM-412 and NM-413 was accompanied by high levels of liver and abdominal radioactivity 24 h postinjection to tumor-bearing rats. Addition of a 2-O-methyl moiety to the propanediol backbone also retarded tumor uptake significantly. A direct comparison between NM-404 and its predecessor, NM-324, in human PC-3 tumor bearing immune-compromised mice revealed a dramatic enhancement in both tumor uptake and total body elimination of NM-404 relative to NM-324. On the basis of imaging and tissue distribution studies in several rodent tumor models, the C18 analogue, NM-404, was chosen for follow-up evaluation in human lung cancer patients. Preliminary results have been extremely promising in that selective uptake and retention of the agent in tumors is accompanied by rapid clearance of background radioactivity from normal tissues, especially those in the abdomen. These results strongly suggest that extension of the human trials to include other cancers is warranted, especially when NM-404 is radiolabeled with iodine-124, a new commercially available positron-emitting isotope. The relatively long physical half-life of 4 days afforded by this isotope appears well-suited to the pharmacodynamic profile of NM-404.
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Affiliation(s)
- Anatoly N Pinchuk
- Department of Pharmacology, The University of Michigan Medical School, 1301 MSRB III, 1150 W. Medical Center Drive, Ann Arbor, Michigan 48109-0632, USA
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Abstract
The use of pH-sensitive liposomes for acid-triggered site-specific drug delivery is one of the more promising approaches to improve the therapeutic index of drugs. Here, we report the synthesis, assembly, and hydrolysis of the first ortho ester phosphocholine (OEPC). The acid hydrolysis of OEPC liposomes consists of a lag phase and a burst phase. The lag time is pH-dependent-the lower the pH, the shorter the time. Upon acid hydrolysis, the OEPC liposomes were transformed into leaky metastable vesicles that rapidly collapsed in the presence of albumin. OEPC, when formulated with cationic lipid, significantly enhanced the transfection efficiency compared with that of the pH-insensitive formulation.
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Affiliation(s)
- Zhaohua Huang
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, 94143-0446
| | - Xin Guo
- Department of Pharmaceutics and Medicinal Chemistry, University of the Pacific, Stockton, California, 95211
| | - Weijun Li
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, 94143-0446
| | - J. Andrew MacKay
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, 94143-0446
| | - Francis C. Szoka
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, 94143-0446
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29
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Chevallier P, Janvier R, Mantovani D, Laroche G. In vitro biological performances of phosphorylcholine-grafted ePTFE prostheses through RFGD plasma techniques. Macromol Biosci 2005; 5:829-39. [PMID: 16134089 DOI: 10.1002/mabi.200500088] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Arterial prostheses made of microporous Teflon (ePTFE) are currently used in vascular surgery as bypasses for small and medium vessels. However, several clinical complications, such as thrombosis, frequently occur in these prostheses when implanted in humans. In this work, an original strategy was developed to improve the hemocompatibility of ePTFE prostheses, based on glow-discharge surface modification followed by chemical grafting of phosphorylcholine, known for its hemocompatible properties. This procedure leads to a covalent attachment of the molecules, therefore preventing their removal by shear stress induced by blood flow at the implant wall. The improvement of the blood compatibility properties of the modified ePTFE arterial prostheses have been investigated by in vitro tests such as thromboelastography, neutrophil adsorption, platelet aggregation, and cell cultures. These in vitro tests put in evidence that thrombogenicity index, platelet aggregation, and neutrophil adhesion were decreased by the molecule grafted on the prostheses. Moreover, the cell growth on the surface of the PRC-grafted prostheses was greatly enhanced in comparison to the virgin prosthesis. Based on these results, it could be concluded that PRC grafting on ePTFE prostheses permit to improve in vitro hemocompatibility and biocompatibility in comparison with their virgin counterpart.
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Affiliation(s)
- Pascale Chevallier
- Unité de Biotechnologie et de Bioingénierie, Centre de Recherche de l'Hôpital Saint-François d'Assise, CHUQ, 10 rue de l'Espinay, Québec G1L 3L5, Canada
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30
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Ho Ye S, Watanabe J, Takai M, Iwasaki Y, Ishihara K. High functional hollow fiber membrane modified with phospholipid polymers for a liver assist bioreactor. Biomaterials 2005; 27:1955-62. [PMID: 16239028 DOI: 10.1016/j.biomaterials.2005.09.041] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 09/26/2005] [Indexed: 01/30/2023]
Abstract
For practical application of a liver assist system with a tissue-conjugated hollow fiber membrane (HFM) bioreactor used in an extracorporeal therapy, it would require a highly sophisticated HFM which has both hemocompatibility on one side and cytocompatibility on the other side. In this study, we present a cellulose acetate (CA) HFM modified with 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers (PMB30 (MPC-co-n-butyl methacrylate) and PMA30 (MPC-co-methacrylic acid) for preparing a novel liver assist HFM bioreactor. A CA/PMB-PMA30 HFM modified asymmetrically on the inner and outer surface with the PMB30 and PMA30 was prepared successfully. Analysis with an X-ray photoelectron spectroscope showed that the intensity of the phosphorus atom attributed to the MPC units on the outer surface of the modified HFM was stronger than that of the inner surface. The PMA30 was immobilized on the outer surface of the CA/PMB30 blend HFM by a chemical condensation reaction. The CA/PMB-PMA30 HFM showed good water and solute permeability in comparison with the CA HFM. The morphologies of the adherent hepatocytes were round in shape in comparison with the cells that adhered on CA HFM. Furthermore, hepatocytes cultured on the inner surface of the CA/PMB-PMA30 HFM showed higher functional expression in terms of urea synthesis and albumin synthesis than that of the CA HFM.
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Affiliation(s)
- Sang Ho Ye
- Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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31
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Chen S, Zheng J, Li L, Jiang S. Strong Resistance of Phosphorylcholine Self-Assembled Monolayers to Protein Adsorption: Insights into Nonfouling Properties of Zwitterionic Materials. J Am Chem Soc 2005; 127:14473-8. [PMID: 16218643 DOI: 10.1021/ja054169u] [Citation(s) in RCA: 712] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, we show the strong resistance of zwitterionic phosphorylcholine (PC) self-assembled monolayers (SAMs) to protein adsorption and examine key factors leading to their nonfouling behavior using both experimental and molecular simulation techniques. Zwitterions with a balanced charge and minimized dipole are excellent candidates as nonfouling materials due to their strong hydration capacity via electrostatic interactions.
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Affiliation(s)
- Shengfu Chen
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA
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32
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Abstract
Alkylphospholipid analogues of perifosine and miltefosine bearing a nitroxide moiety at different positions on an alkyl chain were synthesized as electron paramagnetic resonance (EPR) probes. Their amphiphilic properties were characterized by determining their critical micelle concentration (cmc) and hemolytic activity on erythrocytes both in free and liposomal form. Spin-labeled analogues as membrane components of large unilamellar liposomes containing cholesterol and dicetyl phosphate or in free solution were evaluated using the MTT assay to determine growth inhibition on MT1, MT3, and MCF7 breast cancer cell lines. 4a (IC50 = 56.4 microM) was found to be significantly more active than the perifosine against the MCF-7 cell line. Its high cmc (194.03 microM) and low hemolytic activity shows that its cytotoxic activity might be more specific; therefore, 4a can be an important molecular tool for further EPR investigations.
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Affiliation(s)
- Janez Mravljak
- Faculty of Pharmacy, University of Ljubljana, Askerceva 7, SI-1000 Ljubljana, Slovenia.
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33
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Yaseen M, Wang Y, Su TJ, Lu JR. Surface adsorption of zwitterionic surfactants: n-alkyl phosphocholines characterised by surface tensiometry and neutron reflection. J Colloid Interface Sci 2005; 288:361-70. [PMID: 15927600 DOI: 10.1016/j.jcis.2005.03.024] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 03/06/2005] [Accepted: 03/11/2005] [Indexed: 10/25/2022]
Abstract
The surface adsorption of n-dodecyl phosphocholine (C12PC) has been characterised by a combined measurement of surface tension and neutron reflectivity. The critical micellar concentration (CMC) was found to be 0.91 mM at 25 degrees C in pure water. At the CMC, the limiting area per molecule (A(cmc)) was found to be 52+/-3 A2 and the surface tension (gamma(cmc)) to be ca. 40.0+/-0.5 mN/m. The parallel study of chain isomer n-hexadecyl phosphocholine (C16PC) showed a decrease of the CMC to 0.012 mM and a drop of gamma(cmc) to 38.1+/-0.5 mN/m. However, A(cmc) for C16PC was found to be 54+/-3 A2, showing that increase in alkyl chain length by four methylene groups has little effect on A(cmc). The almost constant A(cmc) suggested that the limiting area per molecule was determined by the bulky PC head group. It was further found that the surface tension and related key physical parameters did not vary much with temperature, salt addition, solution pH or any combination of these, thus showing that surface adsorption and solution aggregation from PC surfactants is largely similar to the zwitterionic betaine surfactants and is distinctly different from ionic and non-ionic surfactants. The thickness of the adsorbed monolayers measured from both dC12hPC and dC16hPC was found to be 20-22 A at the CMC from neutron reflectivity. Neither A(cmc) nor layer thickness varied with alkyl chain length, indicating that as the alkyl chain length became longer it was further tilted away from the surface normal direction and the layer packing density increased. It was also observed that the thickness of the layer varied little with surfactant concentration, indicating that the average conformational orientation of the alkyl chain remained unchanged against varying surface coverage.
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Affiliation(s)
- M Yaseen
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD, UK
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34
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Abstract
The receptor for the lipid mediator sphingosylphosphorylcholine (SPC) has not yet been identified. We describe here the synthesis of the first photoaffinity analogue of SPC. This probe, which contains a 14C-isotopic label in the choline methyl groups and a photoreactive benzophenone in the long-chain base, may be a useful tool in the identification of the G protein coupled receptors that have been postulated to interact directly and specifically with SPC and in the definition of the ligand-binding sites. The key steps in the synthesis are selective reduction of the triple bond in enyne 6 to install the 4E double bond, Suzuki coupling to incorporate the benzophenone photophore at the end of the sphingoid chain, and reduction of the 2-azidoethyl phosphate headgroup of 13 followed by N,N,N-trimethylation to introduce the radiolabel into the choline moiety. The synthesis was completed by the release of the amino group at C2 of the sphingoid base of SPC analogue 2.
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Affiliation(s)
- Xuequan Lu
- Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, New York 11367-1597, USA
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35
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Feng W, Zhu S, Ishihara K, Brash JL. Adsorption of fibrinogen and lysozyme on silicon grafted with poly(2-methacryloyloxyethyl phosphorylcholine) via surface-initiated atom transfer radical polymerization. Langmuir 2005; 21:5980-7. [PMID: 15952850 DOI: 10.1021/la050277i] [Citation(s) in RCA: 262] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Surfaces based on grafted poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) "brushes" with a constant graft density of 0.39 chain/nm2 and chain length from 5 to 200 monomer units were prepared by surface-initiated atom transfer radical polymerization (ATRP) on silicon wafers. The chain length and layer thickness of the poly(MPC) grafts were varied via the ratio of MPC to sacrificial initiator. The surfaces were characterized by water contact angle, XPS, and AFM. The effect of poly(MPC) chain length on fibrinogen and lysozyme adsorption was studied in TBS buffer at pH 7.4. The adsorption of both proteins on the poly(MPC)-grafted surfaces was greatly reduced compared to the unmodified silicon. Adsorption decreased with increasing chain length of the poly(MPC) grafts. Grafts of chain length 200 (MW 59 000) gave adsorption levels of 7 and 2 ng/cm2, respectively, for fibrinogen and lysozyme at 1 mg/mL protein concentration, corresponding to reductions of greater than 98% compared to the unmodified silicon. Adsorption experiments using mixtures of the two proteins showed that the suppression of protein adsorption on the poly(MPC)-grafted surfaces was not strongly dependent on protein size or charge.
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Affiliation(s)
- Wei Feng
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7
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36
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Nam K, Watanabe J, Ishihara K. The characteristics of spontaneously forming physically cross-linked hydrogels composed of two water-soluble phospholipid polymers for oral drug delivery carrier I: hydrogel dissolution and insulin release under neutral pH condition. Eur J Pharm Sci 2005; 23:261-70. [PMID: 15489127 DOI: 10.1016/j.ejps.2004.07.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 07/20/2004] [Accepted: 07/28/2004] [Indexed: 11/19/2022]
Abstract
Hydrogels bearing a phospholipid polar group, 2-methacryloyloxyethyl phosphorylcholine (MPC), were prepared from two aqueous solutions of polymers, water-soluble poly[MPC-co-methacrylic acid (MA)] (PMA) and poly[MPC-co-n-butyl methacrylate (BMA)] (PMB). The hydrogel, which was formed by physical cross-linking spontaneously without any chemical reactions and/or any physical stimuli, showed a controllable insulin release through a pH change in the medium by changing the hydrogen bonds. In this study, the mechanical strength, erosion of the hydrogel caused by polymer dissociation, and the release of insulin were examined with attention to the following three parameters of the MPC polymer: molecular weight of the polymers, composition of PMA and PMB (PMA/PMB ratio), and polymer concentration inside the hydrogel. The hydrogel with the highest mechanical strength was obtained at a PMA/PMB ratio = 3/7 (v/v, by volume ratio) while the hydrogel with the slowest dissolution was obtained at a ratio of 5/5 (v/v). The release was in good match with the dissolution and followed anomalous transport for all, but the diffusion exponent n changed according to the PMA/PMB ratio. An increase in the polymer concentration inside the hydrogel caused an increase in the mechanical strength of the hydrogel. When the polymer concentration was more than 20 wt.%, the absorption of water under neutral pH condition (pH 6.8) was observed. The release of insulin was suppressed below 10% during the swelling process of the hydrogel under neutral pH condition, while release was accelerated during the erosion process of the hydrogel. The relationship between erosion of the hydrogel and the release of the insulin depended on the erosion process of the hydrogel but differed according to the PMA/PMB ratio.
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Affiliation(s)
- Kwangwoo Nam
- Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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37
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Abstract
Dual activity of phosphoryl choline (PC) functional poly(trimethylene carbonate) (PTMC) was found which induces the zwitterionic biomimetic PC group to form physical cross-links with ionomers in the bulk, and at the same time enrich at the surface of cast films. The formation of zwitterionic domains from a bifunctional PC-PTMC-PC (ionomer) provided firm films with a low elastic modulus in contrast to the tacky PTMC starting material (Mn approximately 3900 g/mol) with poor mechanical performance. In addition, the ionomer possessed improved hemocompatible properties that was explained by the enrichment of PC at the surface, suggesting a way to tailor the mechanical performance of biodegradable PTMC-based ionomers while providing its bioactivity. Tailored elasticity while maintaining hemocompatibility of a biodegradable ionomer should be of particular interest for a variety of in vivo applications.
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Affiliation(s)
- Fredrik Nederberg
- Department of Materials Chemistry, Polymer Chemistry, Box 538, Uppsala University, S-751 21 Uppsala, Sweden
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38
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Abstract
A family of new uridine phosphocholine amphiphiles that were prepared using a convenient four-step synthetic route is described. Physicochemical studies (differential scanning calorimetry, small-angle X-ray scattering, UV-vis and circular dichroism spectroscopies, light microscopy, transmission electronic microscopy, and scanning electron microscopy) show that these amphiphiles spontaneously assemble into supramolecular structures including vesicles, fibers, hydrogels, and organogels. In aqueous solution, the amphiphiles possessing saturated alkyl chains self-assemble into DNA-like helical fibers in the crystalline state below T(m) and compact bilayers above the melting temperature (T(m)). The transition from bilayers to fibers is thermally reversible. Above a threshold concentration (>6% w/w), a hydrogel is formed due to an entangled network of the fibers. A therapeutic agent such as DNA can be entrapped within the hydrogel structure. In addition to forming bilayer vesicles and hydrogels in aqueous solution, these nucleoside amphiphiles also form organogels in cyclohexane above T(m). Scanning electron microscopy shows a continuous multilamellar phase in the organogels.
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Affiliation(s)
- Louis Moreau
- Faculté des sciences d'Avignon 33, rue Louis Pasteur, F-84000 Avignon, France
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39
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Park J, Kurosawa S, Watanabe J, Ishihara K. Evaluation of 2-Methacryloyloxyethyl Phosphorylcholine Polymeric Nanoparticle for Immunoassay of C-Reactive Protein Detection. Anal Chem 2004; 76:2649-55. [PMID: 15117211 DOI: 10.1021/ac035321i] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To prepare novel 2-methacryloyloxyethyl phosphorylcholine (MPC)-polymeric nanoparticle (MPC-PNP), water-soluble amphiphilic phospholipid polymer, poly [MPC-co-n-butyl methacrylate (BMA)-co-p-nitrophenyloxycarbonyl poly(ethylene glycol) methacrylate (MEONP) (PMBN)], which has active ester groups for bioconjugation on the side chains, was synthesized. MPC-PNP was prepared by a solvent evaporation technique where the poly(l-lactic acid) was used as core and PMBN was applied as an emulsifier and a surface modifier under systematical design of well-arranged phospholipids polar groups in its surface. Characteristics for MPC-PNP were thoroughly investigated with dynamic light scattering, electrophoresis light scattering, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy measurements. Through a protein adsorption test, the phosphorylcholine group on the surface of MPC-PNPs, which had their active ester groups substituted by glycine, were shown to suppress the nonspecific adsorption of bovine serum albumin. These particles were used for C-reactive protein (CRP) detection, where anti-CRP monoclonal antibodies were immobilized on the MPC-PNP using the active ester group, while the remaining active ester groups were thoroughly reacted with glycine. The detection limit about serum-free CRP in the calibration curve was shown to extend from 0.01 to 10 mg/dL when anti-CRP antibody immobilized MPC-PNP was used for serum-free CRP detection. This compares favorably with measurement using polystyrene nanoparticles that were shown to detect from 0.1 to 10 mg/dL by an immunoagglutination technique. Also, for the detection of CRP in serum, MPC-PNP was shown to give the same calibration curve explained by the efficient suppression of nonspecific binding. Furthermore, denaturation of immobilizing anti-CRP antibody on the MPC-PNP hardly occurred despite increasing the temperature. It is concluded that MPC-PNP is unique due to the design of its interfacial properties, also it will perform well in a diagnostic immunoassay because of its optimized material properties.
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Affiliation(s)
- Jongwon Park
- Department of Materials Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
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40
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Agresta M, D'Arrigo P, Fasoli E, Losi D, Pedrocchi-Fantoni G, Riva S, Servi S, Tessaro D. Synthesis and antiproliferative activity of alkylphosphocholines. Chem Phys Lipids 2003; 126:201-10. [PMID: 14623454 DOI: 10.1016/j.chemphyslip.2003.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Alkylphosphocholines (APC) with one or more methylene groups in the alkyl chain replaced by oxygen atoms or carbonyl groups, or both have been assembled modularly using omega-diols as central building blocks. Out of 25 new compounds of this kind, 11 were evaluated for their antiproliferative activity on four cell lines and compared with miltefosine to evaluate their hemolytic activity (HA) and cytotoxicity on non-tumoral cells (MT2), used as markers of adverse effects. Compound 13 was more active on cancer cell lines than on non-tumoral cells and the data were similar for MTT and thymidine incorporation assays. It had less HA than miltefosine. Compound 13 could therefore be a candidate for the preparation of compounds with higher cytotoxicity on cancer cells and lower general toxicity.
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Affiliation(s)
- Mandy Agresta
- Dipartimento di Chimica, Materiali, Ingegneria Chimica Giulio Natta, Politecnico di Milano and CNR, Istituto di Chimica del Riconoscimento Molecolare Adolfo Quilico, Via Mancinelli 7, 20131 Milano, Italy
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41
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Abstract
This review addresses the non-thrombogenic characteristics of copolymers based on 2-methacryloyloxyethyl phosphorylcholine (MPC), originally developed by Nakabayashi and colleagues. The hypothesis underlying these developments was that such materials would adsorb phospholipids from blood, yielding surfaces with good natural blood compatibility. Methacrylates were found to have excellent properties for this copolymerisation. The characteristics of the MPC copolymers relevant to the improved blood compatibility were minimisation of protein adsorption through an increase in the amount of free water in the MPC hydrogels, which prevents protein conformational change and increased protein stability in solution. Non-thrombogenicity has been evaluated by in vitro, ex vivo and in vivo procedures. Non-thrombogenic dialysis membranes and a durable glucose biosensor have been developed using this MPC copolymer.
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Affiliation(s)
- N Nakabayashi
- Division of Organic Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Surugudai, Kanda, Chiyoda-ku, Tokyo 101-0062,
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42
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Abstract
Novel carbohydrate-based phospholipids containing two saturated C(12) (dilauroyl ribo-phosphocholine) (DLRPC), C(14) (dimyristoyl ribo-phosphocholine) (DMRPC), and C(20) (diarachadonyl ribo-phosphocholine) (DARPC) carboxylic acid chains were synthesized. The physical properties of the supramolecular structures formed by these compounds were compared to those formed by their direct glycerol analogues dilauroyl phosphocholine (DLPC), dimyristoyl phosphocholine (DMPC), and diarachadonyl phosphocholine (DAPC). Modulated differential scanning calorimetry (MDSC) and X-ray diffraction data indicated that with chain lengths < or =14 carbons, the carbohydrate backbone increased the thermal stability of the bilayer below the phase-transition temperature (T(m)) as compared to the glycerol-based lipids. With longer chains (C(20)), the bilayer structure was destabilized as compared to glycerol-based lipids. NMR studies of a DMRPC vesicle dispersion reveal split choline headgroup signals and distinct magnetization transfer effects arising from the "inner" and "outer" surfaces of the bilayer vesicle. Modulated differential scanning calorimetry also demonstrated that glycerol- and carbohydrate-based lipids mix, as evidenced by a single intermediate T(m). In addition, carbohydrate-based lipid/cholesterol mixtures exhibited a decrease in enthalpy with an increase in cholesterol concentration. Unlike glycerol phospholipids, carbohydrate lipids were resistant to enzymatic degradation by phospholipase A(2) (PLA(2)).
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Affiliation(s)
- Geoffrey S Hird
- Department of Chemistry, Paul M. Gross Chemical Laboratory, Duke University, Durham, North Carolina 27708, USA
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43
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Walochnik J, Duchêne M, Seifert K, Obwaller A, Hottkowitz T, Wiedermann G, Eibl H, Aspöck H. Cytotoxic activities of alkylphosphocholines against clinical isolates of Acanthamoeba spp. Antimicrob Agents Chemother 2002; 46:695-701. [PMID: 11850250 PMCID: PMC127497 DOI: 10.1128/aac.46.3.695-701.2002] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Free-living amoebae of the genus Acanthamoeba are causing serious chronic conditions such as destructive keratitis in contact lens wearers or granulomatous amoebic encephalitis in individuals with compromised immune systems. Both are characterized by the lack of availability of sufficiently effective and uncomplicated, manageable treatments. Hexadecylphosphocholine (miltefosine) is licensed for use as a topical antineoplastic agent, but it is also active in vitro against several protozoan parasites, and it was applied very successfully for the treatment of human visceral leishmaniasis. The aim of our study was to evaluate the efficacy of hexadecylphosphocholine and other alkylphosphocholines (APCs) against Acanthamoeba spp. The in vitro activities of eight different APCs against three Acanthamoeba strains of various pathogenicities were determined. All substances showed at least amoebostatic effects, and some of them disrupted the amoebae, as shown by the release of cytoplasmic enzyme activity. Hexadecylphosphocholine exhibited the highest degree of cytotoxicity against trophozoites, resulting in complete cell death at a concentration as low as 40 microM, and also displayed significant cysticidal activity. Hexadecylphosphocholine may be a promising new candidate for the topical treatment of Acanthamoeba keratitis and, conceivably, even for the oral treatment of granulomatous amoebic encephalitis.
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Affiliation(s)
- Julia Walochnik
- Department of Medical Parasitology, Clinical Institute of Hygiene, University of Vienna, Vienna, Austria
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44
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Abstract
O-Phosphonatomethylcholine, an isopolar phosphocholine analogue with a phosphonomethyl ether group replacing a phosphomonoester residue, was prepared by reaction of diisopropyl 2-chloroethoxymethylphosphonate with dimethylamine followed by quaternization of the thus-obtained diisopropyl 2-dimethylaminoethoxymethylphosphonate with iodomethane; the ester groups in the quaternary intermediate were cleaved with bromotrimethylsilane. Replacement of dimethylamine in the reaction sequence by morpholine and/or pyrrolidine gave the N-methylmorpholinium or N-methylpyrrolidinium analogues of O-phosphonatomethylcholine. Reaction of O-phosphonomethylcholine monotetrabutylammonium salt with 1-bromoalkanes in acetonitrile afforded a series of the corresponding monoalkyl (C10-C16) esters. None of these compounds except for the hexadecyl ester exhibited any appreciable cytostatic activity against DU-145, H460, HT-29, or MES-SA cell lines in vitro (evaluated by 3H-Thd incorporation assay). The hexadecyl ester exhibited modest in vitro cytotoxic activity comparable to that of the anticancer drug miltefosine (hexadecyl O-phosphocholine). In vivo evaluation of hexadecyl O-phosphonomethylcholine [transplanted SD lymphoma in inbred SD/cub rats, 10 mg kg(-1) day(-1) intratumoral injection for 10 days] resulted in a 40% decrease in lymphoma mass.
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Affiliation(s)
- A Holý
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, CZ-16610 Praha 6, Czech Republic.
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45
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Court JL, Redman RP, Wang JH, Leppard SW, Obyrne VJ, Small SA, Lewis AL, Jones SA, Stratford PW. A novel phosphorylcholine-coated contact lens for extended wear use. Biomaterials 2001; 22:3261-72. [PMID: 11700798 DOI: 10.1016/s0142-9612(01)00164-8] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The preparation and characterisation of a new phosphorylcholine (PC)-coated silicone hydrogel contact lens for use in extended wear is described. The Michael-type addition of amines to acrylates forms the basis of the synthesis of a novel silicone-based macromer with hydrophilic functionality. It is demonstrated that this macromer can be combined with other silicone-based monomers, hydrophilic monomers and crosslinker to produce a contact lenses formulation. Examples of lenses with water contents of 33% and 46% are illustrated and their properties compared to other commercially available lenses. Materials with comparatively low modulus (<0.3 MPa) and adequate tear strength (>2-4MPa) with excellent elongation to break (>200%) can be obtained using this technology. In addition to the mechanical aspects. both the oxygen and solute permeabilities of the material can be controlled by the hydrophilic: hydrophobic monomer balance in the formulation. to obtain materials with attributes suitable for extended wear use. The PC coating is achieved by means of an in-mould coating (IMC) technique that produces a uniform and stable surface as determined by staining and XPS. The coating imparts both improved lens wettability (advancing contact angle of approximately 50 with virtually no hysteresis) and lower protein adsorption relative to the uncoated lens.
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Affiliation(s)
- J L Court
- Biocompatibles Limited, Farnham, Surrey, UK.
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46
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Hada N, Sato K, Sakushima JI, Goda Y, Sugita M, Takeda T. Synthetic studies on glycosphingolipids from Protostomia phyla: synthesis of amphoteric glycolipid analogues containing a phosphocholine residue from the earthworm Pheretima hilgendorfi. Chem Pharm Bull (Tokyo) 2001; 49:1464-7. [PMID: 11724239 DOI: 10.1248/cpb.49.1464] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two kinds of amphoteric glycosphingolipid analogues from the earthworm Pheretima hilgendorfi were synthesized as follows: The key reaction is a coupling of a phosphocholine group at the position C-6 of 1 and 6 which was attempted using 2-chloro-2-oxo-1,3,2-dioxaphospholane, followed by reaction of the resulting cyclic phosphate intermediate with anhydrous trimethylamine to give 2 and 7. Subsequent debenzylation afforded target compounds (3, 8). Their ability to inhibit the histamine release in vitro was examined.
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Affiliation(s)
- N Hada
- Kyoritsu College of Pharmacy,Tokyo, Japan
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Anderson MA, Shim H, Raushel FM, Cleland WW. Hydrolysis of phosphotriesters: determination of transition states in parallel reactions by heavy-atom isotope effects. J Am Chem Soc 2001; 123:9246-53. [PMID: 11562204 DOI: 10.1021/ja011025g] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The remote label method was used to measure primary and secondary (18)O isotope effects in the alkaline hydrolysis of O,O-diethylphosphorylcholine iodide (DEPC) and the primary (18)O effect in the alkaline hydrolysis of O,O-diethyl-m-nitrobenzyl phosphate (DEmNBP). Both the leaving group of interest (choline or m-nitrobenzyl alcohol) and ethanol can be ejected during hydrolysis due to the similarity of their pK values. The heavy-atom isotope effects were measured by isotope ratio mass spectrometry. Parallel reaction and incomplete labeling corrections were made for both systems. DEPC has a primary (18)O isotope effect of 1.041 +/- 0.003 and a secondary (18)O isotope effect of 1.033 +/- 0.002. The primary (18)O isotope effect for DEmNBP was 1.052 +/- 0.003. These large effects suggest a highly associative transition state in which the nucleophile approaches very close to the phosphorus atom to eject the leaving group. The large values are also indicative of a large compression, or general movement, on the reaction coordinate.
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Affiliation(s)
- M A Anderson
- Institute for Enzyme Research and the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
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Abstract
New biomedical polymers were designed with attention to the surface of biological membranes, i.e. the surface was completely covered with phospholipid polar groups. The polymers with a phosphorylcholine group, 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymerized with hydrophobic alkyl group, could interact with phospholipids in plasma selectively and strongly. The adsorbed phospholipids on the polymer surface were concentrated, organized each other and then formed a self-assembled biomimetic membrane surface. The surface showed excellent resistance for both protein adsorption and blood cell adhesion, i.e. the MPC polymer showed good blood compatibility. Based on these characteristics of the MPC polymer, it was applied to improve the biocompatibility and biostability of an implantable glucose sensor. The relative output current of the sensor covered with the MPC polymer membrane was maintained as the initial level even after 14 days of subcutaneous implantation in a rat. Therefore, it is concluded that the MPC polymer membrane is an excellent material for implantable biomedical devices.
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Affiliation(s)
- K Ishihara
- Department of Materials Science, Graduate School of Engineering, The University of Tokyo, Japan
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Abstract
In search of an efficient method to prepare cholinephosphate headgroups in phospholipids under mild conditions (where the diacylglycerol moiety is not subject to oxidation), a method was developed for phosphorylation using a trialkyl phosphite and I2. The active intermediate is a phosphoryl iodide formed by oxidation of the phosphite with I2. 2-Bromoethanol, dimethyl chlorophosphite, and an alcohol (diglyceride) are converted to a phosphate triester in a one-pot reaction with high yield. In the second reaction, the phosphate triester is demethylated, and the ethyl bromide group is converted to choline by treatment with aqueous trimethylamine. This procedure is applied to the synthesis of hexadecylphosphocholine, and 1,2-didecanoyl-1-deoxy-1-thio-sn-glyceryo-3-phosphocholine.
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Affiliation(s)
- E K Hendrickson
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA
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Abstract
2-Methacryloyloxyethyl phosphorylcholine (MPC) was synthesised and then used in the preparation of crosslinked polymer membranes with lauryl methacrylate, hydroxypropyl methacrylate and trimethoxysilylpropyl methacrylate (crosslinker) comonomers. Some physical aspects of the membrane properties were evaluated in order to establish the basis for the synthesis of a series of post-crosslinkable polymers. These materials were made by copolymerisation of the constituent monomers via a free radical method, and characterised using NMR, FT-IR, viscometry and elemental analysis. The optimum crosslink density and conditions required for curing coatings of these polymers were investigated using atomic force microscopy (AFM) and showed the inclusion of 5 mol% silyl crosslinking agent to be ideal. A nanoindentation technique was employed to determine if the coating developed elasticity upon crosslinking. The biological properties of the coatings were evaluated using a variety of protein adsorption assays and blood contacting experiments, and an enzyme immunoassay was developed to detect E. coli in order to assess the level of bacterial adhesion to these biomaterials. Polymers of this type were shown to be very useful as coating materials for improving the biocompatibility of, or reducing the levels of adherent bacteria to medical devices.
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Affiliation(s)
- A L Lewis
- Research and Development Group, Biocompatibles Ltd, Farnham, Surrey, UK.
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