Novel double-walled microspheres based on chitosan, sodium cellulose sulfate and sodium tripolyphosphate: Preparation, characterization and in vitro release study

Biocompatible coatings based on photo-crosslinkable cellulose derivatives

Materials derived from renewable resources have great potential to replace fossil-based plastics in biomedical applications. In this study, the synthesis of cellulose-based photoresists by esterification with methacrylic acid anhydride and sorbic acid was investigated. These resists polymerize under UV irradiation in the range of λ = 254 nm to 365 nm, with or, in the case of the sorbic acid derivative, without using an additional photoinitiator. Usability for biomedical applications was demonstrated by investigating the adhesion and viability of a fibrosarcoma cell line (HT-1080). Compared to polystyrene, the material widely used for cell culture dishes, cell adhesion to the biomaterials tested was even stronger, as assessed by a centrifugation assay. Remarkably, chemical surface modifications of cellulose acetate with methacrylate and sorbic acid allow direct attachment of HT-1080 cells without adding protein modifiers or ligands. Furthermore, cells on both biomaterials show similar cell viability, not significantly different from polystyrene, indicating no significant impairment or enhancement, allowing the use of these cellulose derivatives as support structures for scaffolds or as a self-supporting coating for cell culture solely based on renewable resources.

A hydroxypropyl methylcellulose/hydroxypropyl starch nanocomposite film reinforced with chitosan nanoparticles encapsulating cinnamon essential oil: Preparation and characterization

Active packaging derived from polysaccharides plays an important role in prolonging the shelf life of food. In this study, cinnamon essential oil (CEO)-loaded chitosan nanoparticles (CNs) were prepared and embedded in hydroxypropyl methylcellulose (HPMC)/hydroxypropyl starch (HPS) blends to enhance the physicochemical and biofunctional properties of the formed films. Different concentrations (25, 50, 75, and 100 μL/mL) of CEOs were encapsulated with CNs to form CEO-CNs, as confirmed by Fourier Transform Infrared Spectrometer (FTIR), X-Ray Diffraction (XRD), and scanning electron microscope (SEM) images. The prepared CEO-CNs were incorporated into the HPMC/HPS film-forming matrix to prepare reinforced nanocomposite films. SEM images showed that the CEO-CNs were dispersed in the HPMC/HPS matrix, thus filling the void space in the composite matrix and significantly improving the mechanical and barrier properties of the bio-nanocomposite films. The elongation at break of the reinforced films improved from 8.54 ± 0.53 MPa to 24.81 ± 0.47 MPa, and the water vapor permeability was reduced by nearly 30 %. FTIR and XRD analyses indicated the formation of hydrogen bonds between CEO-CNs and HPMC/HPS polymer molecules. Release studies showed that the nanocomposite film was capable of sustained release of CEO, which imparted antioxidant (radical scavenging activity of 27.66-42.19 %) and antimicrobial properties (inhibition of Escherichia coli and Aspergillus flavus growth). Therefore, these HPMC/HPS nanocomposite films with enhanced properties may have great potential for food preservation.

Chitosan Nanoparticles as a Promising Nanomaterial for Encapsulation of Pomegranate (Punica granatum L.) Peel Extract as a Natural Source of Antioxidants

The encapsulation of pomegranate peel extract (PPE) in chitosan nanoparticles (CSNPs) is an advantageous strategy to protect sensitive constituents of the extract. This study was aimed to develop PPE-loaded CSNPs and characterize their physical, structural morphology, antioxidant and antimicrobial properties. Spherical NPs were successfully synthesized with a mean diameter of 174–898 nm, a zeta potential (ZP) of +3 – +36 mV, an encapsulation efficiency (EE) of 26–70%, and a loading capacity (LC) of 14–21% depending on their loaded extract concentrations. Based on these results, CSNPs with chitosan:PPE ratio of 1:0.50 (w/w) exhibited good physical stability (ZP = 27 mV), the highest loading (LC = 20%) and desirable encapsulation efficiency (EE = 51%), and thus, selected as optimally loaded NPs. The FTIR analysis of PPE-CSNPs demonstrated no spectral changes indicating no possible chemical interaction between the PPE and CSNPs, which confirms that the PPE was physically entrapped within NPs. Moreover, FTIR spectra of pure PPE showed specific absorption bands (at 3293–3450 cm⁻¹) attributed to the incidence of phenolic compounds, such as tannic acid, ellagic acid and gallic acid. Total phenolic content (TPC) and antioxidant analysis of selected CSNPs revealed that the encapsulated NPs had significantly lower TPC and antioxidant activity than those of pure PPE, indicating that CSNPs successfully preserved PPE from rapid release during the measurements. Antibacterial tests indicated that pure PPE and PPE-loaded CSNPs effectively retarded the growth of Gram-positive S. aureus with a minimum inhibitory concentration (MIC) of 0.27 and 1.1 mg/mL, respectively. Whereas Gram-negative E. coli, due to its protective cell membrane, was not retarded by pure PPE and PPE-CSNPs at the MIC values tested in this study. Gas chromatography-mass spectroscopy analysis confirmed the incidence of various phytochemicals, including phenolic compounds, fatty acids, and furfurals, with possible antioxidant or antimicrobial properties. Overall, CSNPs can be regarded as suitable nanomaterials for the protection and controlled delivery of natural antioxidants/antimicrobials, such as PPE in food packaging applications.

Study on the preparation and mechanism of chitosan-based nano-mesoporous carbons by hydrothermal method

In this paper, the hydrothermal method to synthesize and characterize nano-mesoporous carbons and their synthesis mechanism are reported. Using tri-block Pluronic F127 as a structuring agent and chitosan (CS) as a carbon source, the nano-mesoporous carbons were synthesized by a one-step sol polymerization and hydrothermal process, followed by carbonization at high temperature. The pore structure of the carbon materials was characterized by physical adsorption analyzer, and the morphology was characterized by SEM and TEM. Fourier-transform infrared, Raman and x-ray photoelectron spectroscopy were used to study the synthesis mechanism. The results showed that the self-assembly polymerization reaction between CS and F127 in a weakly acidic system was only implemented driven by the hydrogen bond auxiliary electrostatic interactions initiated by protonated amino groups. The nitrogen from amino groups and acetylamino groups, the oxygen in acetylamino groups, hydroxyl groups and the glycosidic bonds of CS, and the oxygen from the hydrophilic segments of F127 were the main active sites. The mesoporous material possesses a high Brunauer-Emmett-Teller surface area (163 m²/g) and large pore volume (0.462 cm³/g) with pore diameter around 2.1 nm. The nitrogen content was 1.08% and existed in the pore wall as the form of pyridine, pyrrole and quaternary nitrogen.

Investigation on the Preparation, Characteristics, and Controlled Release Model of Paeonol-Loaded Liposome in Carbomer Hydrogel

OBJECTIVE

Paeonol is a phenolic compounce that is volatile. In order to decrease its volatility and achieve controlled release, paeonol-loaded liposome in carbomer hydrogel was prepared by coating with soybean phospholipid via ethanol injection method and then added into the carbomer hydrogel.

METHODS

The quality of paeonol-loaded liposome in carbomer hydrogel was evaluated by the degree of roundness, particle size distribution, zeta potential, entrapment efficiency (filtration method and chitosan neutralization method), viscosity, infrared spectrum, etc. Furthermore, the diffusion from paeonolloaded liposome in hydrogel was studied in vitro.

RESULTS

The results showed that the average particle size of paeonol-loaded liposome was about 401 nm, the potential was -17.8 mV, and the entrapment efficiency was above 45%. The viscosity of paeonol- loaded liposome in hydrogel was 23.972×10-3 Pa*s, and the diffusion rate from paeonol-loaded liposome in hydrogel in vitro was obviously slower than that from the other paeonol preparations.

CONCLUSION

The conclusions could be drawn that paeonol-loaded liposome in hydrogel was a kind of novel preparation, and its diffusion in vitro had obvious controlled-release characteristics, which further proved that it might improve the bioavailability of paeonol.

Strategies for cost-effective and enhanced production of bacterial cellulose

Bacterial cellulose (BC) has received substantial attention because of its high purity, mechanical strength, crystallinity, liquid-absorbing capabilities, biocompatibility, and biodegradability etc. These properties allow BC to be used in various fields, especially in industries producing medical, electronic, and food products etc. A major discrepancy associated with BC is its high production cost, usually much higher than the plant cellulose. To address this limitations, researchers have developed several strategies for enhanced production of BC including the designing of advanced reactors and utilization of various carbon sources. Another promising approach is the production of BC from waste materials such as food, industrial, agricultural, and brewery wastes etc. which not only reduces the overall BC production cost but is also environment-friendly. Besides, exploration of novel and efficient BC producing microbial strains provides impressive boost to the BC production processes. To this end, development of genetically engineered microbial strains has proven useful for enhanced BC production. In this review, we have summarized major efforts to enhance BC production in order to make it a cost-effective biopolymer. This review can be of interest to researchers investigating strategies for enhanced BC production, as well as companies exploring pilot projects to scale up BC production for industrial applications.

Three-dimensionally microporous and highly biocompatible bacterial cellulose–gelatin composite scaffolds for tissue engineering applications

In the current study, highly porous and biocompatible regenerated bacterial cellulose–gelatin (rBC–G) composite scaffolds were fabricated for tissue engineering applications.

Engineered regenerated bacterial cellulose scaffolds for application in in vitro tissue regeneration

Regenerated bacterial cellulose scaffolds were synthesized through solvent casting and particulate leaching method for application in in vitro tissue regeneration.