Preparation of Chitosan Nanoparticles and its Synergistic Effects against Gram Positive and Gram Negative Microorganisms

Performance effectiveness of nano-lignin in production of gel with nano-chitosan for controlling release of salicylic acid

This work deals with assessing the performance of lignin nanoparticles (LNPs) in solving the problem of using salicylic acid as an agrochemical compound, via controlling its release. LNPs, obtained from black liquor, have been used to develop new delivery systems. Gels from chelating of LNPs with chitosan or chitosan nanoparticles (Cs-NPs) in presence or absence of cationic starch are investigated to achieve this essential aim. The nanoparticles are examined by TEM, ATR-FTIR, and XRD techniques. Based on measurements of swelling, encapsulation, release profile, release kinetic modeling of salicylic acid (SA), infrared spectroscopy, thermo-gravimetric analysis and scanning electron microscope the behavior of the investigated nanocomposite gels is assessed. The results show that the SA release profile of Cs-NPs and its nanocomposite with LNPs in phosphate-buffered saline (PBS) (7.4) (51.5-69.4 %) is higher than that of the mixture of water and ethanol (34.9-50.4 %). The release profile in PBS (7.4) demonstrates a trend of prolonged SA release over a 48-hour period. Best control of the SA-release can be achieved by CsNPs-LNPs nanocomposite. Comparing the results with previous literature demonstrates the promising characteristics of these examined gel nanocomposites. The release of SA from nanocomposites is regulated by a diffusion mechanism and follows the Ritger-Peppas and Higuchi models for kinetic release.

Evaluation of fracture resistance of maxillary premolars of different geometrical cavities restored with different composite resins incorporated with chitosan nanoparticles

Background

Composites with 0.2% chitosan nanoparticles (CSN) are used recently; however, this combination needs to be studied in different cavity designs.

Aims

The aim of the study was to compare the fracture resistance of maxillary premolars with different cavity geometries restored with different types of composite resins incorporated with 0.2% CSN.

Methods

About 130 extracted human single-rooted maxillary premolars were embedded in acrylic molds 2 mm below cementoenamel junction, divided into five groups for cavity preparations of standardized dimensions. Group 1: (control) intact teeth (n = 10), Group 2: Class I cavities (n = 40), Group 3: Class II mesio-occlusal (MO) (n = 40), Group 4: Class II mesio-occluso-distal (MOD) (n = 40). Groups 2, 3, and 4 were subdivided into four subgroups for composite restoration; A: Neo spectra ST-Universal (NST); B: Tetric N-Ceram Bulk-fill (TNC); C: NST + CSN; and D: TNC + CSN and tested for fracture resistance using universal testing machine.

Statistical Analysis

One-way analysis of variance and post hoc Tukey's tests were used for data analysis (P ≤ 0.05).

Results

In all groups, the highest fracture resistance was found in MOD cavities, followed by MO and least in Class I cavities. Subgroup D (TNC with CSN) showed the highest fracture resistance in all groups (P ≤ 0.05).

Conclusion

Tetric N-Ceramic bulk fill with 0.25% CSN showed high fracture resistance in cavities with different geometries.

Ultrasonic Synthesis of Nanochitosan and Its Size Effects on Turbidity Removal and Dealkalization in Wastewater Treatment

A detailed study on the synthesis of chitosan nanoparticles under ultrasonication is reported in this paper. By using this simple technique, chitosan particles in nanometer range can be easily prepared without using any harmful and expensive chemicals. The results show that increasing the ultrasonic irradiation time and ultrasonic wave amplitude are the key factors for producing discrete chitosan nanoparticles with narrow particle size distribution. The resulting nanoparticles show superior turbidity removal efficiency (75.4%) and dealkalization (58.3%) in wastewater treatment than the bulk chitosan solid (35.4% and 11.1%, respectively), thus offering an eco-friendly and promising approach for treating wastewater via the coagulation/flocculation process.