A comparative study of polyethylene terephthalate surface carboxylation techniques: Characterization, in vitro haemocompatibility and endothelialization
“…The mean BSA adsorption on PET (control), PET-1[COOH]-Cys, PET-2[COOH]-Cys, PET-3[COOH]-Cys, and PET-4[COOH]-Cys are 17.6, 16.7, 7.1, 1.2, and 8.5 µg/cm 2 , respectively. The results observed on protein adsorption of the PET-[COOH]-Cys were similar to that of the respective carboxylated PET such that PET-1[COOH], PET-2[COOH], PET-3[COOH], and PET-4[COOH] are 16.7, 7.1, 1.9, and 10.2 µg/cm 2 , respectively 29 . Moreover, the PET-3[COOH] and PET-3[COOH]-Cys are the only samples showing a significant reduction in BSA adsorption.Figure 6Protein adsorption on unmodified and modified PET surfaces ( a ) Bovine serum albumin adsorption studies ( b ) Plasma protein adsorption studies.…”
Section: Resultssupporting
confidence: 53%
“…The mean %haemolysis index for PET (control), PET-1[COOH]-Cys, PET-2[COOH]-Cys, PET-3[COOH]-Cys, PET-4[COOH]-Cys are 1.4, 0.5, 0.7, 0.61, and 0.5%, respectively. Carboxylated PET surfaces also exhibited similar values with PET-1[COOH], PET-2[COOH], PET-3[COOH], and PET-4[COOH] 0.7, 0.6, 0.5, and 0.5%, respectively 29 .…”
Section: Resultsmentioning
confidence: 67%
“…The surfaces of the PET were carboxylated using four different methods of surface modification 29 . Cysteine was immobilised onto the unmodified and carboxylated PET surfaces using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) (1-step EDC crosslinking) to form the control, PET-1[COOH]-Cys, PET-2[COOH]-Cys, PET-3[COOH]-Cys, and PET-4[COOH]-Cys.…”
Section: Resultsmentioning
confidence: 99%
“…However, the platelet adhesion on PET-[COOH] and PET-[COOH]-Cys exhibited almost similar values without any statistically significant difference. The mean number of platelets adhered on PET-1[COOH], PET-2[COOH], PET-3[COOH], and PET-4[COOH] were 3.9, 6.7, 1.6, and 7.4 × 10 5 , respectively 29 .Figure 7 In vitro haemocompatibility studies of control and cysteine immobilised PET (PET-[COOH]-Cys) ( a ) quantification of platelet adhesion by LDH assay, ( b ) haemolysis.…”
Section: Resultsmentioning
confidence: 99%
“…In this work, we are immobilising cysteine on the different carboxylated PET surfaces, which were reported in our previous work 29 . EDC was used as the crosslinker to form a stable amide bond between the amine group in cysteine and the carboxyl group of the modified PET.…”
Nitric oxide (NO) is an important signalling molecule involved in haemostasis. NO, present as endogenous S-nitrosothiols, is released by cysteine through a transnitrosation reaction. To exploit this mechanism, cysteine was immobilised onto the different carboxylated polyethylene terephthalate (PET) surfaces using 1-step EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) crosslinking mechanism. Immobilised cysteine concentration and NO release were dependent on the surface carboxyl density. Stability studies showed that the immobilised cysteine concentration and NO release reduced within 6 h. Immobilisation of cysteine derivatives eliminated the possibility of formation of polycysteine and its electrostatic interaction with the carboxylated PET. The immobilised cysteine concentration did not recover after DTT treatment, eliminating the possibility of disulphide bond formation. Further, cysteine was immobilised using a 2-step EDC crosslinking mechanism. Although the cysteine concentration reduced during stability studies, it recovered upon DTT treatment, indicating that cysteine forms amide bonds with the carboxylated PET and the observed decrease in cysteine concentration is probably due to the formation of disulphide bonds. The haemocompatibility of the cysteine immobilised PET surfaces showed similar results compared to the carboxylated PET. The loss of thiol groups due to the disulphide bond restricts the transnitrosation reaction. Hence, these materials can be used primarily in short-term applications.
“…The mean BSA adsorption on PET (control), PET-1[COOH]-Cys, PET-2[COOH]-Cys, PET-3[COOH]-Cys, and PET-4[COOH]-Cys are 17.6, 16.7, 7.1, 1.2, and 8.5 µg/cm 2 , respectively. The results observed on protein adsorption of the PET-[COOH]-Cys were similar to that of the respective carboxylated PET such that PET-1[COOH], PET-2[COOH], PET-3[COOH], and PET-4[COOH] are 16.7, 7.1, 1.9, and 10.2 µg/cm 2 , respectively 29 . Moreover, the PET-3[COOH] and PET-3[COOH]-Cys are the only samples showing a significant reduction in BSA adsorption.Figure 6Protein adsorption on unmodified and modified PET surfaces ( a ) Bovine serum albumin adsorption studies ( b ) Plasma protein adsorption studies.…”
Section: Resultssupporting
confidence: 53%
“…The mean %haemolysis index for PET (control), PET-1[COOH]-Cys, PET-2[COOH]-Cys, PET-3[COOH]-Cys, PET-4[COOH]-Cys are 1.4, 0.5, 0.7, 0.61, and 0.5%, respectively. Carboxylated PET surfaces also exhibited similar values with PET-1[COOH], PET-2[COOH], PET-3[COOH], and PET-4[COOH] 0.7, 0.6, 0.5, and 0.5%, respectively 29 .…”
Section: Resultsmentioning
confidence: 67%
“…The surfaces of the PET were carboxylated using four different methods of surface modification 29 . Cysteine was immobilised onto the unmodified and carboxylated PET surfaces using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) (1-step EDC crosslinking) to form the control, PET-1[COOH]-Cys, PET-2[COOH]-Cys, PET-3[COOH]-Cys, and PET-4[COOH]-Cys.…”
Section: Resultsmentioning
confidence: 99%
“…However, the platelet adhesion on PET-[COOH] and PET-[COOH]-Cys exhibited almost similar values without any statistically significant difference. The mean number of platelets adhered on PET-1[COOH], PET-2[COOH], PET-3[COOH], and PET-4[COOH] were 3.9, 6.7, 1.6, and 7.4 × 10 5 , respectively 29 .Figure 7 In vitro haemocompatibility studies of control and cysteine immobilised PET (PET-[COOH]-Cys) ( a ) quantification of platelet adhesion by LDH assay, ( b ) haemolysis.…”
Section: Resultsmentioning
confidence: 99%
“…In this work, we are immobilising cysteine on the different carboxylated PET surfaces, which were reported in our previous work 29 . EDC was used as the crosslinker to form a stable amide bond between the amine group in cysteine and the carboxyl group of the modified PET.…”
Nitric oxide (NO) is an important signalling molecule involved in haemostasis. NO, present as endogenous S-nitrosothiols, is released by cysteine through a transnitrosation reaction. To exploit this mechanism, cysteine was immobilised onto the different carboxylated polyethylene terephthalate (PET) surfaces using 1-step EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) crosslinking mechanism. Immobilised cysteine concentration and NO release were dependent on the surface carboxyl density. Stability studies showed that the immobilised cysteine concentration and NO release reduced within 6 h. Immobilisation of cysteine derivatives eliminated the possibility of formation of polycysteine and its electrostatic interaction with the carboxylated PET. The immobilised cysteine concentration did not recover after DTT treatment, eliminating the possibility of disulphide bond formation. Further, cysteine was immobilised using a 2-step EDC crosslinking mechanism. Although the cysteine concentration reduced during stability studies, it recovered upon DTT treatment, indicating that cysteine forms amide bonds with the carboxylated PET and the observed decrease in cysteine concentration is probably due to the formation of disulphide bonds. The haemocompatibility of the cysteine immobilised PET surfaces showed similar results compared to the carboxylated PET. The loss of thiol groups due to the disulphide bond restricts the transnitrosation reaction. Hence, these materials can be used primarily in short-term applications.
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