Fig 1.
Schematic of NTAP treatment setup of sutures.
A schematic that illustrates the NTAP treatment of suture fragments. Note that sutures were fixed to glass slide over the grounding electrode using tapes, and parts of suture fragment remaining under the tape were removed after completion of NTAP treatment.
Fig 2.
Antimicrobial effect of NTAP treatment on contaminated sutures.
(A) Growth of E. coli and S. aureus around untreated suture samples was clearly visible on TSA plates while no bacterial growth was observed around 3-minute NTAP treated sutures. Sutures on the left sides of petri dishes are untreated (control suture) and sutures on the right sides of petri dishes are NTAP treated samples. (B) Logarithmic growth of S. aureus per cm suture fragment of control and 3-minute NTAP treated sutures. (C) Logarithmic growth of E. coli per cm suture fragment of control and 3-minute NTAP treated sutures.
Fig 3.
Prevention of bacterial colonization on suture fragments after NTAP treatment.
(A) Growth of S. aureus and E. coli was observed around the untreated and antimicrobial ALCALACTINE suture samples while no bacterial growth was observed around the 7-minute NTAP treated suture samples on TSA plates. Sutures on the left sides of petri dishes are untreated (control suture) and sutures on the right sides of petri dishes are NTAP treated samples. (B) Logarithmic growth of S. aureus per cm suture fragment of control and 3-minute NTAP treated sutures. (C) Logarithmic growth of E. coli per cm suture fragment of control and 3-minute NTAP treated sutures. Note that around 3-log growth of S. aureus and E. coli was observed on untreated suture samples while no growth was observed on 7-minute NTAP treated suture samples.
Fig 4.
Persistency of bacterial colonization prevention after NTAP treatment.
(A) Representative images of growth of S. aureus and E. coli on agar plates 10 days after 7-minute NTAP treatment. Note that no growth of S. aureus and E. coli was observed PDO and PGCL sutures even after 10 day later NTAP treatment on TSA plates. Sutures on the left sides of petri dishes are untreated (control suture) and sutures on the right sides of petri dishes are NTAP treated samples. (B) Logarithmic growth of S. aureus on per cm suture fragment 1, 3, 5, 7 and days after 7-minute NTAP treatment. Colonization of S. aureus on PDO and PGCL sutures was prevented at given time-points, however S. aureus adhered on PGLA and PGA sutures even one day after 7-minute NTAP treatment. (C) Logarithmic growth of E. coli on per cm suture fragment 1, 3, 5, 7 and days after 7-minute NTAP treatment. Colonization of S. aureus on PDO and PGCL sutures was prevented at given time-points, while S. aureus colonization on PGLA and PGA sutures increases as the delay time increases.
Fig 5.
Change in water contact angle on NTAP treated sutures in comparison with untreated sutures.
(A) After 7-minute NTAP treatment of sutures, the water contact angle drops to 0° on all suture materials. (B) In consequence of 0° contact angle obtained by 7-minute NTAP treatment, dispersion of water droplet on suture samples could be observed by naked eye.
Fig 6.
Degradation of suture samples after 7-minute NTAP treatment.
Degradation of (A) PGLA, (B) PGA, (C) PDO and (D) PGCL sutures in PBS solution at 37°C was determined by weight measurements until suture fragments got shattered during manipulation.
Fig 7.
Maximum tensile force that sutures could withstand before and after 7-minute NTAP treatment.
The maximum tensile force that PGA and PGCL sutures could withstand wasn’t altered by 7-minute NTAP treatment. However, 7-minute NTAP treatment led a decrease of the maximum tensile force that PGLA and PDO sutures could withstand.
Fig 8.
Effect of NTAP treated sutures on wound healing.
(A) Light microscope images clearly show accelerated wound healing by introduction of 7-minute NTAP treated suture samples. Remaining wound areas when (B) PGLA, (C) PGA, (D) PDO and (E) PGCL sutures incubated on wound scratch model were quantified using ImageJ software.
Fig 9.
Scanning electron microscopy images of suture samples before and after NTAP treatment.
SEM images of (A) PGLA, (B) PGA, (C) PDO and (D) PGCL sutures were obtained before and after 7-minute NTAP treatment at 100X and 2500X magnifications to evaluate structural and surface characteristics, respectively.
Fig 10.
FTIR spectra of sutures before and after NTAP treatment.
Chemical modifications caused on (A) PGLA, (B) PGA, (C) PDO and (D) PGCL sutures by 7-minute NTAP treatment was evaluated by using FTIR. FTIR spectra revealed that, 7-minute NTAP treatment, caused a decrease in relative absorption intensity of C-C groups and increase in relative absorption intensity of C–O and C = O groups suggesting increasing hydrophilicity.
Fig 11.
XPS C1s spectra of sutures before and after NTAP treatment.
Chemical modifications caused on (A) PGLA, (B) PGA, (C) PDO and (D) PGCL sutures by 7-minute NTAP treatment was evaluated by using XPS. XPS spectra of C 1s revealed an increase in oxygen signals upon 7-minute NTAP treatment.
Table 1.
Atomic composition and relative peak intensities of suture before and After 7-minute NTAP treatment.