In this study, we fabricated a series of nanocomposites using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser that was operated with specific parameters, as follows: wavelength, 1064 nm; energy output, 500 mJ; pulse number, 500; and frequency, 1 Hz. Four distinct types of nanocomposites were produced: chitosan (CS); chitosan-titanium oxide (CS-TiO₂); chitosan-silver (CS-Ag); and a composite of chitosan, titanium oxide, and silver (CS-TiO₂-Ag). A transmission electron microscopy (TEM) analysis was employed to characterize these nanocomposites, revealing particle sizes of 13, 15, 34, and 32 nm for CS, CS-TiO₂, CS-Ag, and CS-TiO₂-Ag, respectively. We further evaluated the antimicrobial efficacy of these nanocomposites against two prevalent bacterial strains, i.e., Escherichia coli and Klebsiella. Our observations indicated varying degrees of bactericidal effectiveness, as represented by the diameters of the killing zones. More specifically, for E. coli, the inhibition diameters were 20 mm (CS), 36 mm (CS-Ag), 38 mm (CS-TiO₂), and 40 mm (CS-TiO₂-Ag). Similar results were observed for Klebsiella, with inhibition diameters of 28 mm (CS), 35 mm (CS-Ag), 38 mm (CS-TiO₂), and 43 mm (CS-TiO₂-Ag). Moreover, the CS-TiO₂-Ag nanocomposite was further studied regarding its potential for use in environmental applications, especially water purification. An experiment combining 30 mL of the CS-TiO₂-Ag nanocomposite with 30 mL of contaminated water resulted in successful purification, as corroborated by a subsequent analysis. In conclusion, this study offered important insights into the fabrication of chitosan-based nanocomposites and their respective antimicrobial performances against E. coli and Klebsiella. Furthermore, it illustrated the promising potential of the CS-TiO₂-Ag nanocomposite for use in water purification applications, thus demonstrating its potential for broader environmental utility.

The rGO-Ag NPs nanocomposite was synthesized by an easy, low-cost, one-step chemical method. The nanocomposite was analyzed by UV-Vis spectroscopy and atomic force microscope (AFM) to verify the properties of the nanoparticles. The study of the optical properties showed that there are two peaks, one of which belongs to silver and is 400 nm, and the other is related to graphene oxide at 268 nm. The AFM examination of the rGO-Ag NPs revealed that the average grain size is 71.26 nm, and this indicates that the material is within the nanoscale. The rGO-Ag NPs nanocomposite was applied as an antagonist against various types of bacteria that cause gum and tongue infections, and the results showed that with the increase in the nanocomposite concentration, the killing rate of bacteria increases. This means that the killing increases with increasing volumes of rGO-Ag NPs, and the best one is 40 μL. The result shows that the rGO-Ag NPs show a relationship between adding volumes of the nanomaterial and the percentage killing of bacteria, which is directly proportional. Additionally, through UV-Vis spectroscopy, the absorbance of the rGO-Ag NPs was determined, so that the laser with a wavelength of 405 nm was chosen to be applied to the same kinds of bacteria and for different periods of time with the use of a 40 μL volume of the rGO-Ag NPs, and it was found that with increasing the irradiation period, the percentage of bacteria killed increases. It showed that increasing the irradiation period with volume stability of 40 μL causes a higher killing rate. The study indicated that using nanocomposite and laser is a method to remove the infection from the gums and tongue. These results are promising and can be applied in the treatment of gum and tongue infections after clinical studies.

In this work, By using the laser ablation technique (PLAL) to fabricate novel PMMA/G/Ag nanocomposites with less laser energy and short time ablation and study the structural, morphological and optical properties. The X-ray diffraction (XRD) confirmed that the GNPs and AgNPs in the PMMA matrix have a crystallite size increased with increasing the pulse number. Also, the SEM images confirm the homogeneous distribution of the GNPs and AgNPs in the PMMA matrix and the sizes of particles in the nanoscale. Additionally, the link between GNPs and AgNPs in the polymer matrix has been confirmed by the FTIR. Moreover, UV-VIS spectroscopy was studied and confirm the nanocomposite has optical properties with the presence of the polymer as a host and calculating the optical energy gap. For that, this novel nanocomposite with these properties promising for many applications. Finally, the study proved that the PLAL is very suitable for decorated graphene and metal on the polymer matrix with lower pulse laser energy and short ablation time.