Key Engineering Materials Vol. 977

Abstract: Cellulose nanosphere (CNS) was isolated from corn husk by delignification, bleaching, acid hydrolysis, dialysis, and sonication. Successful isolation of CNS was confirmed by FTIR Analysis. The isolated CNS was found to have an average diameter of 18 nm and crystallinity index of 70% using TEM and XRD Analysis, respectively. A decrease in onset degradation temperature (T_onset) and an increase in residual mass were also observed in the TG analysis of cellulose fiber and CNS. Nanocomposite hydrogels using poly (ethylene glycol) dimethacrylate (PEGDMA) as matrix and CNS as nanofiller was prepared by UV-curing. FTIR Analysis revealed similar transmittance patterns among all the treatments. Thermal characterization showed that the addition of CNS lowers the T_onset and T_max while increasing the temperature required for the total degradation of the UV-cured nanocomposite hydrogels.

Abstract: Pancreatic cancer, often referred to as “the silent killer”, presents with minimal or no symptoms in its early stages, leading to late detection when surgical resection is no longer the optimal treatment option. Gemcitabine (GEM), one of the leading chemotherapeutic drug for advanced stages of cancer, is a crucial treatment for pancreatic cancer. However, the low 5-year survival rate of pancreatic cancer patients highlight the limited effectiveness of current treatments. In recent years, mesoporous silica nanoparticles (MSNP) have garnered significant attention in both scholarly and pharmaceutical fields due to their unique combination of properties including stable porous structure and high loading capacities. This research aims to investigate the potential of MSNP as a carrier for anticancer drugs, specifically GEM. MSNP was successfully synthesized in the laboratory using sol-gel method with tetraethyl orthosilicate (TEOS) as silica source and cetyltrimethylammonium bromide (CTAB) as surfactant template. Comprehensive morphological and physical characterizations of the MSNP product were performed through transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, element mapping, X-ray diffractometry (XRD), and accelerated surface area porosimetry (ASAP). The results demonstrate that MSNP exhibits desirable properties for drug loading, including a stable mesoporous structure with pore size of ~ 4.94 nm, a high surface area of about 278.32 m²/g, and average particle diameter of approximately 85 nm. The effects of incubation time and initial GEM concentrations were studied to determine the optimal drug loading parameters for the MSNP vehicle. The successful loading of up to 24 µg of GEM in 1 mg of MSNP achieved in an optimized incubation time of 2 hour, validates the tremendous potential of MSNP as a potential anticancer drug carrier in pancreatic cancer treatment. These findings provide a valuable reference for future research and investigations in this promising field.

Abstract: The evolving bacteria defense mechanism against antimicrobial agents due to the overuse and misuse of antimicrobial chemicals has led to a catastrophic problem - antimicrobial resistance, this has spurred the quest for innovative antibacterial approach to inhibit bacterial growth effectively without using any chemicals. Tailored nano- and microstructured architecture, inspired by natural nanotopography such as those found on cicada wings, hold great promise in antibacterial activity due to their unique mechano-antibacterial properties. Among the various nano-/microfabrication techniques, the two-photon polymerisation (TPP) stands out as a versatile and precise approach to fabricate arbitrarily functional three-dimensional structures with sub-micrometre resolution. The process involves the use of femtosecond laser pulses to induce polymerization of a biocompatible acrylate-based photoresin in a precise spatial pattern to generate the nano-/microarchitecture. In this study, we investigated the influence of key fabrication parameters, such as laser power, exposure time, and interface value to achieve the final pre-defined nano-/microarchitecture. Microscopy analysis showed that nanostructure of heights between 350-650 nm; 300-400 nm diameter; and increasing center-to-center distances of 700-2000 nm were successfully fabricated. The mechano-antibacterial feasibility of the two photon-designed nanoarchitecture were tested against P. aeruginosa pathogenic bacteria commonly encountered in healthcare settings. Our results showed that the TPP nano-/microarchitecture demonstrated intriguing antibacterial activity through physico-mechanical interactions between the nano-/microarchitectures and bacteria, creating surfaces that exhibit bactericidal activity. This study paves the way for advanced antibacterial applications in the field of nanotechnology and biomedicine, making a significant contribution to the ongoing efforts in combating antimicrobial resistance and promoting global health.

Abstract: Silver and palladium nanoparticles were prepared by in situ chemical reduction using Sodium Borohydride as a reducing agent at 18^°C. The synthesis of pure and hybrid cryogels and the incorporation of silver and palladium nanoparticles inside the cryogel network, was confirmed by x-ray diffraction analysis and energy dispersive x-ray respectively. The antibacterial activities were checked by using the hybrid cryogels against Staphylococcus aureus (ATCC: 2593) and Escherichia coli (ATCC: 25922) bacteria. After taking into account the facile synthetic process and the adsorption performance, these cryogels can serve as good candidates for antibacterial purposes.