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Phomopsidione-Loaded Chitosan Polyethylene Glycol (PEG) Nanocomposite Dressing for Pressure Ulcers

Chin IBI, Yenn TW, Ring LC, Lazim Y, Tan WN, Rashid SA, et al.

J Pharm Sci, 2020 09;109(9):2884-2890.
PMID: 32534882 DOI: 10.1016/j.xphs.2020.06.005

Pressure ulcers are commonly associated with microbial infections on the wounds which require an effective wound dressing for treatment. Thus far, the available silver dressing has shown tremendous result, however, it may cause argyria and complicate the internal organ function. Hence, our study aims to develop and characterize phomopsidione-loaded chitosan-polyethylene glycol nanocomposite hydrogel (C/PEG/Ph) as an antimicrobial dressing. Physically, the C/PEG/Ph hydrogel demonstrated a uniform light blue color, soft, flexible, and elastic, with no aggregation form. The evaluation via Fourier Transform Infrared (FTIR) exposed the C/PEG/Ph hydrogel has a notable shift towards lower frequency at 1600 and 1554 cm-1. For drug release test, the phomopsidione attained plateau at 24 h, with a total release of 67.9 ± 6.4% from the C/PEG/Ph hydrogel. There was a null burst release effect discovered throughout the experimental period. The C/PEG/Ph hydrogel showed significant results against all 4 Gram-negative bacteria and 1 yeast, with 99.99-100% reduction of microbial growth. The findings revealed that the C/PEG/Ph hydrogel can potentially act as an antimicrobial dressing for pressure ulcers.
Thymol-Loaded Polymeric Nanoparticles Improve the Postharvest Microbiological Safety of Blueberries

Ab Rashid S, Tong WY, Leong CR, Tan WN, Lee CK, Anuar MR, et al.

Food Technol Biotechnol, 2023 Jun;61(2):151-159.
PMID: 37457903 DOI: 10.17113/ftb.61.02.23.7595

RESEARCH BACKGROUND: The presence of Yersinia enterocolitica on raw food products raises the concern of yersiniosis as most of the berries are consumed raw. This is a challenging issue from the food safety aspect since it could increase the occurrence of foodborne diseases among humans. Thus, it is crucial to implement an effective sanitation before the packaging.
EXPERIMENTAL APPROACH: This study aims to synthesize and characterize thymol-loaded polyvinyl alcohol (Thy/PVA) nanoparticles as a sanitizer for postharvest treatment of blueberries. Thy/PVA nanoparticles were characterized by spectroscopic and microscopic approaches, prior to the analyses of antimicrobial properties.
RESULTS AND CONCLUSIONS: The diameter size of the nanoparticles was on average 84.7 nm, with a surface charge of -11.73 mV. Based on Fourier transform infrared (FTIR) measurement, the Thy/PVA nanoparticles notably shifted to the frequency of 3275.70, 2869.66, 1651.02 and 1090.52 cm-1. A rapid burst was observed in the first hour of release study, and 74.9 % thymol was released from the PVA nanoparticles. The largest inhibition zone was displayed by methicillin-resistant Staphylococcus aureus (MRSA), followed by Y. enterocolitica and Salmonella typhi. However, amongst these bacteria, the inhibition and killing of Y. enterocolitica required a lower concentration of Thy/PVA nanoparticles. The treatment successfully reduced the bacterial load of Y. enterocolitica on blueberries by 100 %.
NOVELTY AND SCIENTIFIC CONTRIBUTION: Thymol is a plant-based chemical without reported adverse effects to humans. In this study, by using the nanotechnology method of encapsulation with PVA, we improved the stability and physicochemical properties of thymol. This nanoparticle-based sanitizer could potentially promote the postharvest microbiological safety of raw berries, which may become an alternative practice of food safety.
Nanoparticle-laden contact lens for controlled release of vancomycin with enhanced antibiotic efficacy

Tong WY, Tan WN, Kamarul Azizi MA, Leong CR, El Azab IH, Lim JW, et al.

Chemosphere, 2023 Oct;338:139492.
PMID: 37451643 DOI: 10.1016/j.chemosphere.2023.139492

Vancomycin is the last resort antibiotic for the treatment of severe bacterial keratitis. Its clinical application is limited due to its hydrophilicity and high molecular weight. To overcome this, this study aims to develop nanoparticles-laden contact lens for controlled ocular delivery of vancomycin. Polyvinyl alcohol (PVA) was used as encapsulant material. The nanoparticles had a negative surface charge and an average size of 147.6 nm. A satisfactory encapsulation efficiency (61.24%) was obtained. The release profile was observed to be slow and sustained, with a release rate of 1.29 μL mg-1 h-1 for 48 h. Five out of 6 test bacteria were suppressed by vancomycin nanoparticles-laden contact lens. Vancomycin is generally ineffective against Gram-negative bacteria and unable to pass through the outer membrane barrier. In this study, vancomycin inhibited Proteus mirabilis and Pseudomonas aeruginosa. Nano-encapsulation enables vancomycin to penetrate the Gram-negative cell wall and further destroy the bacterial cells. On Hohenstein challenge test, all test bacteria exhibited significant reduction in growth when exposed to vancomycin nanoparticles-laden contact lens. This study created an effective and long-lasting vancomycin delivery system via silicone hydrogel contact lenses, by using PVA as encapsulant. The antibiotic efficacy and vancomycin release should be further studied using ocular in vivo models.
Fulltext Homalomena pineodora essential oil nanoparticle inhibits diabetic wound pathogens

Rozman NAS, Tong WY, Leong CR, Anuar MR, Karim S, Ong SK, et al.

Sci Rep, 2020 02 24;10(1):3307.
PMID: 32094395 DOI: 10.1038/s41598-020-60364-0

Essential oil of Homalomena pineodora inhibits diabetic pathogens; however, the activity was not sustainable when applied as wound dressing. This study aims to synthesise the essential oil nanoparticle using chitosan. The nanoparticles were synthesised with ion gelation method, confirmed by spectroscopic analysis. The spherical nanoparticles display a size of 70 nm, with strong surface charge of +24.10 mV. The nanoparticles showed an initial burst release followed by a slow release pattern for 72 h, following the first order of kinetic. The release behaviour was ideal for wound dressing. The antimicrobial activity was broad spectrum. The formation of nanoparticle enhanced the antimicrobial efficacy of the essential oil. The nanoparticle also showed a concentration-dependent killing behaviour on time-kill assay. In the 3D collagen wound models, the nanoparticles reduced the microbial growth by 60-80%. In conclusion, H. pineodora nanoparticles showed pharmaceutical potential in inhibiting microbial growth on diabetic ulcers.