Nowadays polylactic acid (PLA) is widely used in orthopedics surgeries as implants material due to well mechanical characterization and biomedical properties. But the PLA implants suffer from slow degradation rate when it is used in real-life scenario. In the present research work, the PLA specimens using additive manufacturing technique are fabricated and further assessed for mechanical characterization and its degradation behavior with different parameters. The change in weight of scaffolds was measured using digital weight measure, and pH value was measured using pH meter. Morphology and elemental composition of PLA scaffolds were characterized by SEM and EDS, respectively, while compressive strength is measured by the universal testing machine. Apatite formation and biocompatible nature of fabricated scaffolds were analyzed by in vitro simulated body fluid study. The outcomes of characterization exposed that scaffold with 60% infill percentage had maximum porosity, which is beneficial for the apatite formation and osseointegration. The average change in compressive strength was measured as 49.79 MPa after 14 days and 46.11 MPa after 28 days, whereas the average change in pH value was measured as 5.67 and 5.27 after 14 and 28 days of incubation period, respectively. The degradation rate of specimen 3 was 27.92% less than that of specimen 1, 35.69% less than that of specimen 5, and 87.98% more than that of specimen 9. This study concludes the positive effect of process parameters on degradation rate and biocompatible behavior of PLA implants.
Reactive oxygen species, probably hydroxyl radicals (OH.), have been suggested to be generated during arachidonic acid (AA) metabolism and, once released, these species can modify the rate and extent of various reactions involved in AA metabolism. We have studied this phenomenon in washed human platelets. OH. generation was quantitated using 14C-benzoic acid as a specific trap in a continuous ionization chamber system. Resting platelets did not produce any detectable signal, whereas addition of AA resulted in gradual OH. production with peak values detected at approximately 20 min. Similar studies conducted under nitrogen or after boiling the platelets almost abolished OH. generation. Aspirin had no significant effect, whereas 5,8,11,14-eicosatetraynoic acid decreased the signal by greater than 90%, thus suggesting that OH. is produced primarily through the lipoxygenase pathway. Superoxide dismutase (SOD) and catalase had no effect and, as expected, phenol and mannitol decreased OH. production considerably, by greater than 50% and 90%, respectively. Azide and cyanide also reduced the OH. generation by about two thirds. We conclude that OH. is generated during AA metabolism by human platelets. It is primarily produced via the lipoxygenase pathway and may require a heme-dependent peroxidase. This highly reactive oxidant may play an important role in normal and abnormal hemostasis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.