目的:观察静电纺聚乳酸-乙醇酸.蛋壳膜蛋白(PLGA.SEP)混合纤维膜在体外降解过程中结构、性能的变化。方法:采用静电纺丝技术制备PLGA.SEP混合纤维膜和PLGA纤维膜(对照)。将两种纤维膜浸泡在37℃,pH=7.4的模拟体液(simulated body fluid ...目的:观察静电纺聚乳酸-乙醇酸.蛋壳膜蛋白(PLGA.SEP)混合纤维膜在体外降解过程中结构、性能的变化。方法:采用静电纺丝技术制备PLGA.SEP混合纤维膜和PLGA纤维膜(对照)。将两种纤维膜浸泡在37℃,pH=7.4的模拟体液(simulated body fluid solution,SBF)中进行降解实验,并分别于降解后2、4、6周检测两种电纺纤维膜降解前后的质量、断裂强度、表面形貌和热分解温度。结果:两种电纺纤维膜的质量、断裂强度均随降解时间的延长而逐渐降低,在降解前2周,下降速度较快,从2周到6周速度减慢;在降解2、4、6周各时间点PLGA.SEP纤维膜的失重率、断裂强度降低率均高于PLGA纤维膜,两者有显著性差异(P<0.05)。两种纤维膜均在降解6周时,纤维吸水发生溶胀,纤维之间粘连,孔径变小,但是结构仍完整,没有出现纤维断裂现象。PLGA.SEP和PLGA电纺纤维膜降解前后均有一个吸热峰,并且随着降解时间的延长,热分解温度逐渐降低,其中PLGA纤维膜在降解各时间点的热分解温度均高于PLGA.SEP纤维膜。结论:PLGA.SEP纤维膜在SBF中降解6周时结构仍完整并保持一定力学强度,可作为一种具有发展潜力的可吸收性引导组织再生(guided tissue regeneration,GTR)膜。展开更多
Poly(lactide-co-glycolide acid)(PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used mate...Poly(lactide-co-glycolide acid)(PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used materials for drug delivery and biomedical systems, also being present in several US Food and Drug Administration-approved carrier systems and therapeutic devices. For both applications, the quantification of the polymer is inalienable. During the development of a production process, parameters like yield or loading efficacy are essential to be determined. Although PLGA is a well-defined biomaterial,it still lacks a sensitive and convenient quantification approach for PLGA-based systems. Thus, we present a novel method for the fast and precise quantification of PLGA by RP-HPLC. The polymer is hydrolyzed into its monomers, glycolic acid and lactic acid. Afterwards, the monomers are derivatized with the absorption-enhancing molecule 2,4′-dibromoacetophenone. Furthermore, the wavelength of the derivatized monomers is shifted to higher wavelengths, where the used solvents show a lower absorption,increasing the sensitivity and detectability. The developed method has a detection limit of 0.1 mg/mL,enabling the quantification of low amounts of PLGA. By quantifying both monomers separately, information about the PLGA monomer ratio can be also directly obtained, being relevant for degradation behavior. Compared to existing approaches, like gravimetric or nuclear magnetic resonance measurements, which are tedious or expensive, the developed method is fast, ideal for routine screening, and it is selective since no stabilizer or excipient is interfering. Due to the high sensitivity and rapidity of the method, it is suitable for both laboratory and industrial uses.展开更多
目的建立乳酸-羟基乙酸共聚物(25:75)(PLGA)相对分子质量(Mr)及其分布的测定方法。方法采用TSK gel G3000HHR色谱柱,以四氢呋喃为流动相,流速1.0mL/min,柱温40℃,示差折光检测器。结果凝胶排阻色谱法测定PLGA Mr及其分布系数,有良好的...目的建立乳酸-羟基乙酸共聚物(25:75)(PLGA)相对分子质量(Mr)及其分布的测定方法。方法采用TSK gel G3000HHR色谱柱,以四氢呋喃为流动相,流速1.0mL/min,柱温40℃,示差折光检测器。结果凝胶排阻色谱法测定PLGA Mr及其分布系数,有良好的线性、准确性及重复性。结论此法简便快速,结果准确,重复性好,可作为PLGA Mr及其分布的测定方法。展开更多
Background The most important objective of transplant studies in the injured spinal cord has been to provide a favorable environment for axonal growth. Moreover, the continuing discovery of new grafts is providing new...Background The most important objective of transplant studies in the injured spinal cord has been to provide a favorable environment for axonal growth. Moreover, the continuing discovery of new grafts is providing new potentially interesting transplant candidates. Our purpose was to observe the morphological and functional repair effects of the co-transplantation of neural stem cell （NSC）, Schwann ceils （SCs） and poly lactide-co-glycolide acid （PLGA） on the spinal cord injury of rats.Methods A scaffold of PLGA was fabricated. NSCs and SCs were cultured, with the NSCs labeled with 5-bromodeoxyuridine, and the complex of NSC/PLGA or NSC＋SCs/PLGA were constructed. Thirty-six Wistar rats were randomly divided into three groups： group A （transplantation of PLGA）, group B （transplantation of NSC/PLGA） and group C （transplantation of NSC＋SCs/PLGA）. The 3 mm length of the right hemicord was removed under the microscope in all rats. The PLGA or the complex of PLGA-celIs were implanted into the injury site. Basso-Beattie-Bresnahan （BBB）locomotion scores, motor and somatosensory evoked potential of lower limbs were examined to learn the rehabilitation of sensory and motor function at 4 weeks, 8 weeks, 12 weeks and 24 weeks after injury. All the recovered spinal cord injury （SCI） tissues were observed with HE staining, immunohistochemistry, and transelectronmicroscopy to identify the survival, migration and differentiation of the transplanted cells and the regeneration of neural fibres at 4 weeks, 8 weeks,12 weeks and 24 weeks after injury.Results （1） From 4 weeks to 24 weeks after injury, the BBB locomotion scores of cell-transplanted groups were better than those of the non-cell-transplanted group, especially group C （P 〈0.05）. The amplitudes of the somatosensory evoked potential （SEP） and motor-evoked potential （MEP） were improved after injury in groups B and C, but the amplitude of SEP and MEP at 4 weeks was lower than that at 12 weeks and 24 weeks after injury. Com展开更多
文摘Poly(lactide-co-glycolide acid)(PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used materials for drug delivery and biomedical systems, also being present in several US Food and Drug Administration-approved carrier systems and therapeutic devices. For both applications, the quantification of the polymer is inalienable. During the development of a production process, parameters like yield or loading efficacy are essential to be determined. Although PLGA is a well-defined biomaterial,it still lacks a sensitive and convenient quantification approach for PLGA-based systems. Thus, we present a novel method for the fast and precise quantification of PLGA by RP-HPLC. The polymer is hydrolyzed into its monomers, glycolic acid and lactic acid. Afterwards, the monomers are derivatized with the absorption-enhancing molecule 2,4′-dibromoacetophenone. Furthermore, the wavelength of the derivatized monomers is shifted to higher wavelengths, where the used solvents show a lower absorption,increasing the sensitivity and detectability. The developed method has a detection limit of 0.1 mg/mL,enabling the quantification of low amounts of PLGA. By quantifying both monomers separately, information about the PLGA monomer ratio can be also directly obtained, being relevant for degradation behavior. Compared to existing approaches, like gravimetric or nuclear magnetic resonance measurements, which are tedious or expensive, the developed method is fast, ideal for routine screening, and it is selective since no stabilizer or excipient is interfering. Due to the high sensitivity and rapidity of the method, it is suitable for both laboratory and industrial uses.
文摘目的建立乳酸-羟基乙酸共聚物(25:75)(PLGA)相对分子质量(Mr)及其分布的测定方法。方法采用TSK gel G3000HHR色谱柱,以四氢呋喃为流动相,流速1.0mL/min,柱温40℃,示差折光检测器。结果凝胶排阻色谱法测定PLGA Mr及其分布系数,有良好的线性、准确性及重复性。结论此法简便快速,结果准确,重复性好,可作为PLGA Mr及其分布的测定方法。
基金This work was supported by grants from the National Natural Science Foundation of China （No. 30370543, No. 30540450581）.
文摘Background The most important objective of transplant studies in the injured spinal cord has been to provide a favorable environment for axonal growth. Moreover, the continuing discovery of new grafts is providing new potentially interesting transplant candidates. Our purpose was to observe the morphological and functional repair effects of the co-transplantation of neural stem cell （NSC）, Schwann ceils （SCs） and poly lactide-co-glycolide acid （PLGA） on the spinal cord injury of rats.Methods A scaffold of PLGA was fabricated. NSCs and SCs were cultured, with the NSCs labeled with 5-bromodeoxyuridine, and the complex of NSC/PLGA or NSC＋SCs/PLGA were constructed. Thirty-six Wistar rats were randomly divided into three groups： group A （transplantation of PLGA）, group B （transplantation of NSC/PLGA） and group C （transplantation of NSC＋SCs/PLGA）. The 3 mm length of the right hemicord was removed under the microscope in all rats. The PLGA or the complex of PLGA-celIs were implanted into the injury site. Basso-Beattie-Bresnahan （BBB）locomotion scores, motor and somatosensory evoked potential of lower limbs were examined to learn the rehabilitation of sensory and motor function at 4 weeks, 8 weeks, 12 weeks and 24 weeks after injury. All the recovered spinal cord injury （SCI） tissues were observed with HE staining, immunohistochemistry, and transelectronmicroscopy to identify the survival, migration and differentiation of the transplanted cells and the regeneration of neural fibres at 4 weeks, 8 weeks,12 weeks and 24 weeks after injury.Results （1） From 4 weeks to 24 weeks after injury, the BBB locomotion scores of cell-transplanted groups were better than those of the non-cell-transplanted group, especially group C （P 〈0.05）. The amplitudes of the somatosensory evoked potential （SEP） and motor-evoked potential （MEP） were improved after injury in groups B and C, but the amplitude of SEP and MEP at 4 weeks was lower than that at 12 weeks and 24 weeks after injury. Com
