ABSTRACT
Fluorescence spectroscopy was used to investigate the efficiency of coupling peptides to gold nanoparticles via 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride-N-hydroxysuccinimide (EDC-NHS).The experiment conditions including buffer solution, pH value and concentrations of buffer solution, concentrations of NHS and EDC, concentration ratios of NHS to EDC, and coupling reaction time on the coupling efficiency were investigated and optimized.The experimental results indicated that the optimized experimental conditions were as follows: 25 mmol/L HEPES buffer solution, pH 7.0;2∶1 of concentration ratio of NHS to EDC, 0.4 mol/L NHS, 0.2 mol/L EDC, and coupling reaction time of 24 h.This study may provide references for the relative research involving coupling peptide or protein with gold nanoparticles
ABSTRACT
Objective To investigate the optimal method for synthesizing thiolated doxorubicin .Methods Thiolated doxorubi-cin was synthesized through two different methods .Doxorubicin was reacted with 2-iminothiolane (2-IT) and S-acetylthioglycolic acid N-hydroxysuccinimide ester (SATA),respectively.The synthesized thiolated doxorubicin was further characterized by HPLC and MS -ESI techniques .Several factors including molar ratios as well as reaction time were evaluated .Results The results showed that thiolat-ed doxorubicin could be synthesized via both of the two methods successfully .Thiolated doxorubicin could be stable when doxorubicin was reacted with SATA .But the crude thiolated doxorubicin could be cyclized easily when doxorubicin was reacted with 2-IT.Conclu-sion Thiolated doxorubicin prepared with SATA is more feasible than that with 2-IT.
ABSTRACT
[Objective]Porous collagen type Ⅱ matrices crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl)carbodⅡmide(EDC) and N-hydroxysucinimide(NHS) were developed as scaffolds for cartilage tissue engineering.[Method]Collagen type Ⅱ matrix was crosslinked by EDC/NHS,and then freeze-dried to achieve collagen scaffolds.The porous characteristics of the prepared scaffolds were tested by using diffenent methods,including laser scanning confocal microscopy (LSCM),scanning electron microscopy (SEM) and mechanical testing machine.The chondrocytes labeled by GFP were planted in crosslinked collagen type Ⅱ,and observed by LSCM.[Result](1) The mechanical properties of cross-linked matrices increased significantly,reaching 2.18?0.47MPa.(2)The degradation of cross-linked matrices decreased by 8.28% after 4 hours.The pore size was about 90?m,and their average porosity and water capacity reached 93.39% and 97.78%,respectively.3.Chondrocytes were in good condition in the crosslinked collagen.[Conclusion]The present work indicates that EDC/NHS-crosslinked collagen type Ⅱ could keep the properties and biocompatibility of collagen,besides,the mechanical strength increased and the degradation was decreased.It will be suitable for cartilage tissue engineering purposes.