Purpose: The present study aims to address this issue by functionalizing GO with Pluronic F127 (PF) as a means to mitigate toxicity and resolve the biocompatibility of GO. Although results from previous studies generally indicated that Pluronic functionalized GO exhibits relatively low toxicity to living organisms, reports that emphasize on its toxicity, particularly during embryonic developmental stage, are still scarce.
Methods: In the present study, two different sizes of native GO samples, GO and NanoGO, as well as PF-functionalized GO, GO-PF and NanoGO-PF, were prepared and characterized using DLS, UV-Vis, Raman spectroscopy, FTIR, and FESEM analyses. Toxicological assessment of all GO samples (0-100 µg/mL) on zebrafish embryonic developmental stages (survival, hatching and heart rates, and morphological changes) was recorded daily for up to 96 hours post-fertilization (hpf).
Results: The toxicity effects of each GO sample were observed to be higher at increasing concentrations and upon prolonged exposure. NanoGO demonstrated lower toxicity effects compared to GO. GO-PF and NanoGO-PF were also found to have lower toxicity effects compared to native GO samples. GO-PF showed the lowest toxicity response on zebrafish embryo.
Conclusion: These findings highlight that toxicity is dependent on the concentration, size, and exposure period of GO. Functionalization of GO with PF through surface coating could potentially mitigate the toxicity effects of GO in embryonic developmental stages, but further investigation is warranted for broader future applications.
METHODS: 1.5% (w/v) chitosan films with Chrysanthemum morifolium essential oil (0% to 6% (v/v)) were produced through homogenization, the casting of a film solution in a petri dish and convection drying. The edible film was evaluated in terms of its physical (color, thickness, water vapor permeability), mechanical (puncture strength, tensile strength, elongation at break) and chemical properties (antioxidant assay, Fourier Transform Infrared Spectroscopy (FTIR)).
RESULTS: With an increasing concentration of Chrysanthemum morifolium in the chitosan film, the test values of physical properties such as tensile strength, puncture force, and elongation at break declined significantly. However, the thickness, water permeability, and color profile (L*, a*, b*) values of the chitosan film increased. Similarly, the scavenging effect of antioxidant assay increased (from 4.97% to 18.63%) with a rise in Chrysanthemum morifolium concentration. 2%, 3%, and 4% of Chrysanthemum morifolium in the chitosan film showed a significant inhibition zone ranging from 2.67 mm to 3.82 mm against Staphylococcus aureus, a spoilage bacterium that is commonly found in chicken and beef products. The storage and pH tests showed that 4% of Chrysanthemum morifolium in the film maintained pH level (safe to consume), and the shelf life was extended from 3 days to 5 days of meat storage.
CONCLUSIONS: This study demonstrated that the incorporation of 4% (v/v) Chrysanthemum morifolium extract into 1.5% (w/v) chitosan film extends the storage duration of raw meat products noticeably by reducing Staphylococcus aureus activity. Therefore, it increases the quality of the edible film as an environmentally friendly food packaging material so that it can act as a substitute for the use of plastic bags. Future studies will be conducted on improving the tensile strength of the edible film to increase the feasibility of using it in the food industry. In addition, the microstructure and surface morphology of the edible film can be further determined.
Methods: Colectomy samples were obtained from 11 adults (mean age 45.7, six males) who were residents of Northeastern Peninsular Malaysia. Microplastics were identified following chemical digestion of specimens and subsequent filtration. The samples were then examined for characteristics (abundance, length, shape, and color) and composition of three common polymer types using stereo- and Fourier Transform InfraRed (FTIR) microscopes.
Results: Microplastics were detected in all 11 specimens with an average of 331 particles/individual specimen or 28.1 ± 15.4 particles/g tissue. Filaments or fibers accounted for 96.1% of particles, and 73.1% of all filaments were transparent. Out of 40 random filaments from 10 specimens (one had indeterminate spectra patterns), 90% were polycarbonate, 50% were polyamide, and 40% were polypropylene.
Conclusion: Our study suggests that microplastics are ubiquitously present in the human colon.