diphenols and PEG have so far not been studied as medical implant materials A number of studies have illustrated the strong effects of PEg on the activity and conformation of proteins in solution[15-17. However, the role of lower-range PEG interactions that may allow protein adsorption and cell adhesion on biomaterial has been largely overlooked. Thus, the biological "regulatory"behavior of PEG-bearing surfaces is not clearly understood, especially at low and intermediate levels of Peg surface concentration Thus, there is a need to design biomaterial surfaces that are systematically responsive to protein adsorption in a precise, tissue-specific manner Unfortunately, the current treatment options for articular cartilage repair suffer from certain limitations [1, 2]. The clinical need for improved methods for articular repair have motivated many researchers to explore tissue engineering approaches Practical application to environmental-friendly materials has been restricted by the low melting point, and more efforts have been, therefore, directed to overcome the thermal unstability Although many reports have been published on the polymer blends of PCL [3-9 there are only a few on the study of biodegradation In view of the widespread use of silicones(polysiloxanes), it is rather surprising that the literature documents have seldom reported systematic approaches to the synthesis of structurally defined oligosiloxanes Although synthetic poly( id)have been widely investigated, very few practical applications have been identified for these polymers 三,指出本文的研究内容、目的及其独到之处 The objective of the present study was to synthesize well -defined ABa copolymers. and to investigate feasibility of preparing phase-separated structures in blends. In this work we attempt to minimize transesterification reactions Our model PEG-variant surface were based on a family of tyrosine-derived biomaterials, which have been well characterized both in vitro and in vivo, and have shown great promise for use ineering appl This study reports for the first time<慎用,可加: as far as we know, to the best of our knowledge> that PEG, when present on a biomaterial surface in small, controlled amount, can modify, in a systematic manner, the attachment of proteins and in turn, the adhesion and migration of cells
6 diphenols and PEG have so far not been studied as medical implant materials. A number of studies have illustrated the strong effects of PEG on the activity and conformation of proteins in solution [15-17]. However, the role of lower-range PEG interactions that may allow protein adsorption and cell adhesion on biomaterial has been largely overlooked. Thus, the biological “regulatory” behavior of PEG-bearing surfaces is not clearly understood, especially at low and intermediate levels of PEG surface concentration. Thus, there is a need to design biomaterial surfaces that are systematically responsive to protein adsorption in a precise, tissue-specific manner. Unfortunately, the current treatment options for articular cartilage repair suffer from certain limitations [1,2]. The clinical need for improved methods for articular repair have motivated many researchers to explore tissue engineering approaches… Practical application to environmental-friendly materials has been restricted by the low melting point, and more efforts have been, therefore, directed to overcome the thermal unstability. Although many reports have been published on the polymer blends of PCL [3-9], there are only a few on the study of biodegradation. In view of the widespread use of silicones (polysiloxanes),1 it is rather surprising that the literature documents have seldom reported systematic approaches to the synthesis of structurally defined oligosiloxanes. Although synthetic poly(amino acid) have been widely investigated, very few practical applications have been identified for these polymers. 三 指出本文的研究内容﹑目的及其独到之处 The objective of the present study was to synthesize well –defined ABA copolymers…and to investigate feasibility of preparing phase-separated structures in blends…In this work we attempt to minimize transesterification reactions. Our model PEG-variant surface were based on a family of tyrosine-derived biomaterials, which have been well characterized both in vitro and in vivo, and have shown great promise for use in tissue engineering applications. This study reports for the first time <慎用 可加 as far as we know to the best of our knowledge> that PEG, when present on a biomaterial surface in small, controlled amount, can modify, in a systematic manner, the attachment of proteins and in turn, the adhesion and migration of cells
In this paper, we present data on.. Recently, we found that.... In this paper mechanistic aspects of the polymerization as well as polymerization conditions suppressing decarboxylation are discussed in detail The present work was aimed at studying Here we report the introduction of PEG blocks into the backbone of polycarbonates to form oly(ether carbonate)s. .. The effects of length of the Peg block on the properties of the resulting copolymers were investigated. Correlations were established between the copolymer composition and its material properties such as glass transition temperature, mechanical strength,. and drug release. In addition, preliminary data on the in vitro interaction of cells with these polymers were obtained. In a separate publication, the inverse temperature transitions observed for this class of polymers are described 33 ● Experimental 通常用一般过去时、被动态 根据实验内容通常可见到以下几类: 材料的来源及合成制备 直接买到的药品一般需指明来源 Chemicals<小标题> Amino acid(Bachem), 2-(2-amino-ethyl)pyridine( Fluka) and 2-hydroxypyridine(Acros)were used as received ZnEt, was purchased from Aldrich and was used as received 直接购买的溶剂等辅助药品只需简单提及或略过: All other materials were commercially available and used as received unless otherwise noted All other chemicals were of analytical grade and were used as received 经纯化处理的药品一般需说明纯化方法 Materials<小标题 Cyclotrimethylene carbonate(Ingelheim, Germany) was purified by distillation in vacuo and recrystallized from THF was dried and distilled over CaH2 twice under reduced pressure Ethylacetate was dried over K2 CO3 and distilled
7 In this paper, we present data on … Recently, we found that…. In this paper mechanistic aspects of the polymerization as well as polymerization conditions suppressing decarboxylation are discussed in detail. The present work was aimed at studying … Here we report the introduction of PEG blocks into the backbone of polycarbonates to form poly(ether carbonate)s. … The effects of length of the PEG block on the properties of the resulting copolymers were investigated. Correlations were established between the copolymer composition and its material properties such as glass transition temperature, mechanical strength, …and drug release. In addition, preliminary data on the in vitro interaction of cells with these polymers were obtained. In a separate publication, the inverse temperature transitions observed for this class of polymers are described [33]. z Experimental 通常用一般过去时 被动态 根据实验内容通常可见到以下几类 一 材料的来源及合成制备 直接买到的药品一般需指明来源 Chemicals <小标题> Amino acid (Bachem), 2-(2-amino-ethyl)pyridine (Fluka) and 2-hydroxypyridine (Acros) were used as received. ZnEt2 was purchased from Aldrich and was used as received. 直接购买的溶剂等辅助药品只需简单提及或略过 All other materials were commercially available and used as received unless otherwise noted. All other chemicals were of analytical grade and were used as received. 经纯化处理的药品一般需说明纯化方法 Materials <小标题> Cyclotrimethylene carbonate (Ingelheim, Germany) was purified by distillation in vacuo and recrystallized from THF. …was dried and distilled over CaH2 twice under reduced pressure. Ethylacetate was dried over K2CO3 and distilled
All solvents were freshly distilled before use 合成的产物要说明具体合成方法 y-Benzylglutamate was prepared by the method of Gutmann and Boissinnas (101 was synthesized according to Ref. [4] were synthesized according to published procedures [1 Trimethylene carbonate was synthesized following a procedure described elsewhere. The product was recrystallized twice from diethyl ether. White crystal was obtained in 55% yield: mp 45C). The H-NMR spectrum(4H, 4.50 ppm; 2H, 2.21 ppm) was consistent with that reported previously. 25 Novozym-435(2.0 g)was suspended in 25 mL of nanopure water in a 100 mL round-bottomed flask fitted with a water cooled condenser. The lipase suspension was refluxed for 14 h. The suspension was then allowed to cool to room temperature, and water was removed by freeze drying.. The reaction vials were capped tightly and shaken vigorously for a few minutes. The reaction vials were then placed in a constant-temperature water bath maintained at 37C for 3 h with magnetic stirrin Pentaerythritol (50.0 g, 0.36 mol) and p-toluene-sulfonic acid monohydrate(0.61 g)were dissolved in 500 mL of N, N-dimethylformamide at about 80C, and then the mixture was allowed to cool undisturbed. When the solution cooled to about 40oC. stirring was starte and 55.4 mL of 2, 2-dimethoxypropane(0. 36 mol) was added. After stirring for 24 h at room temperature, the solution was stirred at room temperature with 9.0 g of based-treated DOWEX lXZ-100 ion exchange resin for I h and filtered, and then the solvent was evaporated under reduced pressure below 85C... After the treatment with this resin, the dry product was ground and extracted, first with light petroleum ether(bp 40-60C) for 6 h and then with diethyl ether for 12 h, collected and dried. Yield: 40.0 g, white crystals(61.9 of theory); mp 124.5-125.5°C.H-NMR(300MHz, DMSO-d6):1.28ppm(s,6H), Synthesis of Cyclic Carbonate Monomer<小标题> Triethylamine (84.0 g, 0.825 mol) was added dropwise to a solution of 1,3-propanediol (29.9 g, 0.393 mol) and ethyl chloroformate (85.4 g, 0.786 mol) in 2L of THF at0C over a period 30 min. The reaction mixture was stirred for 2h at room temperature. Precipitated triethylamine hydrochloride salt was filtered off, and the filtrate was concentrated under vacuum. The residue was recrystallized three times from THF-ether 1000 g of glycolic acid was placed in a three necked flask fitted with a stirrer, distillation head and condenser, a thermalmeter for monitoring the temperature of the melt, and a nitrogen bleed. I g of Sb2O3 was added and the vessel was heated to 120C. Polycondensation began and as the rate of water elimination fell, the temperature was increased to 180C and
8 All solvents were freshly distilled before use. 合成的产物要说明具体合成方法 -Benzylglutamate was prepared by the method of Gutmann and Boissinnas [10]. …was synthesized according to Ref. [4]. …were synthesized according to published procedures [1]. Trimethylene carbonate was synthesized following a procedure described elsewhere.25 The product was recrystallized twice from diethyl ether. White crystal was obtained in 55% yield: mp 45°C). The 1 H-NMR spectrum (4H, 4.50 ppm; 2H, 2.21 ppm) was consistent with that reported previously. 25 Novozym-435 (2.0 g) was suspended in 25 mL of nanopure water in a 100 mL round-bottomed flask fitted with a water cooled condenser. The lipase suspension was refluxed for 14 h. The suspension was then allowed to cool to room temperature, and water was removed by freeze drying…. The reaction vials were capped tightly and shaken vigorously for a few minutes. The reaction vials were then placed in a constant-temperature water bath maintained at 37 °C for 3 h with magnetic stirring…. Pentaerythritol (50.0 g, 0.36 mol) and p-toluene-sulfonic acid monohydrate (0.61 g) were dissolved in 500 mL of N, N-dimethylformamide at about 80 °C, and then the mixture was allowed to cool undisturbed. When the solution cooled to about 40 °C, stirring was started and 55.4 mL of 2,2-dimethoxypropane (0.36 mol) was added. After stirring for 24 h at room temperature, the solution was stirred at room temperature with 9.0 g of based-treated DOWEX 1XZ-100 ion exchange resin for 1 h and filtered, and then the solvent was evaporated under reduced pressure below 85 °C. …After the treatment with this resin, the dry product was ground and extracted, first with light petroleum ether (bp 40-60 °C) for 6 h and then with diethyl ether for 12 h, collected and dried. Yield: 40.0 g, white crystals (61.9 % of theory); mp 124.5-125.5 °C. 1 H-NMR (300 MHz, DMSO-d6): 1.28 ppm (s, 6H), … Synthesis of Cyclic Carbonate Monomer <小标题> Triethylamine (84.0 g, 0.825 mol) was added dropwise to a solution of 1,3-propanediol (29.9 g, 0.393 mol) and ethyl chloroformate (85.4 g, 0.786 mol) in 2L of THF at 0 °C over a period 30 min. The reaction mixture was stirred for 2h at room temperature. Precipitated triethylamine hydrochloride salt was filtered off, and the filtrate was concentrated under vacuum. The residue was recrystallized three times from THF-ether. 1000 g of glycolic acid was placed in a three necked flask fitted with a stirrer, distillation head and condenser, a thermalmeter for monitoring the temperature of the melt, and a nitrogen bleed. 1 g of Sb2O3 was added and the vessel was heated to 120 °C. Polycondensation began and as the rate of water elimination fell, the temperature was increased to 180 °C and
pressure reduced gradually from 760-5 mmHg over a period of 4-6 hours The structure of htC was confirmed by Ftir and H-NMR ,仪器表征 <各测试仪器型号、参数均根据具体实验而定,以下例子仅限于具体文献,不可照抄。> Nuclear Magnetic Resonance(NMR) Spectroscopy H-NMR spectra were recorded on a Bruker ARX-250 spectrometer at 250 MHz Fourier Transform-Infrared Spectroscopy(FTIR) A P-E 1720 FTIR spectrometer was used to obtain the spectra(16 scans, resolution 2 cm )of he monomer and polymers over the range from 4000 to 400 cm Differential Scanning Calorimetry(DSC) Differential Scanning Calorimetry(DSC) was carried out with a Perkin-Elmer DSC 7 thermal analyzer. All the samples were heated at 20C/min heating rate from 25C to 200C for th first scan, then cooled at 50-100C/min to 25C, and immediately heated a second time Peak melting temperatures(Tm)and melting enthalpy(AHm)were measured on the first scan, and glass transition temperatures (Tg) were measured on the second scan DSC was measured using a Perkin-Elmer DSC 7 calorimeter with heating and cooling rates of 0°C/ min from-20°Cto200°C Scanning Electron Microscopy(SEM) Fiber samples were fractured in liquid nitrogen to obtain tidy cross-section, and then sputter-coated with gold and visualized by SEM(PHILIPS XL 30) Samples were then covered by an ultrathin layer of gold and observed and micrographed with a scanning electron microscope(JSM 6400) X-ray Analysis Wide-angle X-ray scattering of a solution cast film aged for 2 weeks at 40C was performed using a Philips Vertical Diffractometer with Bragg-Brentano geometry and a graphite diffracted beam monochrometer at 40 k v/20 mA and Cu Ka radiation(1.5405 A). A scanning speed of 2/min with a sample interval of 0.05 was used Gel Permeation Chromatography(GPC) GPC analyses were carried out using a Waters HPLC pump with an ERMA 75 15A refractive index detector and a Carlo Erba UVis 20 ultraviolet detector Molecular weight data was obtained by gel permeation chromatography(GPC), using two PL el columns connected to a Water 410 RI detector(Waters Corp, MA)
9 pressure reduced gradually from 760-5 mmHg over a period of 4-6 hours…. The structure of C HTC was confirmed by FTIR and 1 H-NMR. 二 仪器表征 <各测试仪器型号﹑参数均根据具体实验而定 以下例子仅限于具体文献 不可照抄 > Nuclear Magnetic Resonance (NMR) Spectroscopy 1 H-NMR spectra were recorded on a Bruker ARX-250 spectrometer at 250 MHz. Fourier Transform-Infrared Spectroscopy (FTIR) A P-E 1720 FTIR spectrometer was used to obtain the spectra (16 scans, resolution 2 cm-1) of the monomer and polymers over the range from 4000 to 400 cm-1. Differential Scanning Calorimetry (DSC) Differential Scanning Calorimetry (DSC) was carried out with a Perkin-Elmer DSC 7 thermal analyzer. All the samples were heated at 20 °C/min heating rate from 25 °C to 200 °C for the first scan, then cooled at 50-100 °C/min to 25 °C, and immediately heated a second time. Peak melting temperatures (Tm) and melting enthalpy ( Hm) were measured on the first scan, and glass transition temperatures (Tg) were measured on the second scan. DSC was measured using a Perkin-Elmer DSC 7 calorimeter with heating and cooling rates of 10 °C/min from -20 °C to 200 °C. Scanning Electron Microscopy (SEM) Fiber samples were fractured in liquid nitrogen to obtain tidy cross-section, and then sputter-coated with gold and visualized by SEM (PHILIPS XL 30). Samples were then covered by an ultrathin layer of gold and observed and micrographed with a scanning electron microscope (JSM 6400). X-ray Analysis Wide-angle X-ray scattering of a solution cast film aged for 2 weeks at 40 °C was performed using a Philips Vertical Diffractometer with Bragg-Brentano geometry and a graphite diffracted beam monochrometer at 40 kV/20 mA and Cu Ka radiation (1.5405 Å). A scanning speed of 2°/min with a sample interval of 0.05° was used. Gel Permeation Chromatography (GPC) GPC analyses were carried out using a Waters HPLC pump with an ERMA 7515A refractive index detector and a Carlo Erba UVIS 20 ultraviolet detector. Molecular weight data was obtained by gel permeation chromatography (GPC), using two PL gel columns connected to a Water 410 RI detector (Waters Corp, MA)