Preparation nanoparticle by ionic cross-linked emulsified chitosan and its antibacterial activity

Synthesis of carob honey loaded chitosan nanoparticles and determination of its antimicrobial potential and cytotoxic effect on breast cancer cell line

Embedding natural products into chitosan nanoparticles (CNP) is an effective way to produce a novel combination with better antimicrobial and anticancer activities. Therefore, this study aims to incorporate carob honey (CH) into CNP, determine its potential antimicrobial along with antiproliferative activities, by well diffusion and MTT cell viability assays, respectively. Successful loading of CH in CNP was confirmed after due characterization. The nanoparticles, synthesized by ionic gelation method, produced a small (101.3 ± 4.13 nm), stable (+27.27 ± 0.95 mV), and monodispersed (0.2265 ± 0.0027) CH-loaded CNP (CHCNP). The best antibacterial activity occurred in Klebsiella pneumoniae (K. pneumoniae) (23 ± 0 mm to 16 ± 1.7 mm) followed by Escherichia coli (E. coli) (18 ± 2.0 mm to 10 ± 1 mm). Meanwhile, Aspergillus niger (A. niger) and Aspergillus flavus (A. flavus) were evenly inhibited with inhibition zones in the range of 15 ± 3 mm to 7 ± 0.8 mm and 15 ± 5 mm to 9 ± 1.4 mm, respectively. CHCNP showed a remarkable cytotoxic effect on MDA-MB-231 according to concentration and time, with IC50 of 25 ± 5 to 18 ± 2.6 μg/mL within 24-72 h. These findings demonstrated the feasibility of loading CH in CNP to form a nanoformulation that could potentially serve as a target-specific therapeutic agent in the treatments of microbial infections and breast cancer. However, there is a need for further research on the safety, dosage optimization, in vivo studies and mechanisms of action of the nanoparticles.

Chitosan-sodium dodecyl sulfate nanoparticles: a promising approach for enhancing antibacterial activity against Streptococcus mutans of grapefruit seed extract

In this study, grapefruit seed extract (GSE)-loaded nanoparticles (GNPs) were formed through ionic gelation between chitosan (CS) and sodium dodecyl sulfate (SDS) to improve antibacterial activity against oral bacteria, such as Streptococcus mutans, and to demonstrate the impact of particle size on antimicrobial activity. Particle size was negatively correlated with the antibacterial effect; the smaller GNPs showed significantly higher antimicrobial activity than the other particles. The optimal formulation of the smaller GNPs was determined using response surface methodology (RSM). The optimized GNPs improved antibacterial activity, which was approximately 3.5 times higher than that of free GSE (p < 0.05). Moreover, the GNPs were effective at reducing bacterial growth, achieving a reduction of more than 3 log10 CFU/mL within the first 3 h and complete inhibition of bacterial growth after 9 h. This study suggests that nanoencapsulation significantly enhances its antibacterial activity against oral bacteria.

Development of a Chitosan-Silver Nanocomposite/β-1,3-Glucan/Hyaluronic Acid Composite as an Antimicrobial System for Wound Healing

An ideal wound dressing should be biocompatible, exhibit high antibacterial activity, and promote blood coagulation in the wound. In this study, we used chitosan as a multifunctional template to synthesize silver nanoparticles embedded in chitosan (Ag NP@CHI), which were then combined with β-1,3-glucan/hyaluronic acid (HA) to form an Ag NP@CHI/β-1,3-glucan/HA composite material with biocompatibility, wound healing-promoting properties, and antibacterial activity. A high concentration of chitosan led to the formation of smaller crystalline structures of Ag NPs and improved their dispersion within the chitosan matrix, but decreased their antibacterial potency. The Ag NP@CHI prepared with 1.0 mg/mL chitosan had the smallest particle size and good antibacterial activity. Compared to Ag NP@CHI, the prepared Ag NP@CHI/β-1,3-glucan/HA composite significantly enhanced biocompatibility, cell migration, hemocompatibility, and blood coagulation, with a minor reduction in antibacterial efficiency due to restricted ionic silver release and diffusion. With its high biocompatibility, hemocompatibility, promotion of blood coagulation and wound healing, and antibacterial efficiency, Ag NP@CHI@β-1,3-glucan/HA demonstrates potential as a wound healing composite in the future.

Chitosan and Its Nanoparticles: A Multifaceted Approach to Antibacterial Applications

Chitosan, a multifaceted amino polysaccharide biopolymer derived from chitin, has extensive antibacterial efficacy against diverse pathogenic microorganisms, including both Gram-negative and Gram-positive bacteria, in addition to fungi. Over the course of the last several decades, chitosan nanoparticles (NPs), which are polymeric and bio-based, have garnered a great deal of interest as efficient antibacterial agents. This is mostly due to the fact that they are used in a wide variety of applications, including medical treatments, food, chemicals, and agricultural products. Within the context of the antibacterial mechanism of chitosan and chitosan NPs, we present a review that provides an overview of the synthesis methods, including novel procedures, and compiles the applications that have been developed in the field of biomedicine. These applications include wound healing, drug delivery, dental treatment, water purification, agriculture, and food preservation. In addition to this, we focus on the mechanisms of action and the factors that determine the antibacterial activity of chitosan and its derivatives. In conjunction with this line of inquiry, researchers are strongly urged to concentrate their efforts on developing novel and ground-breaking applications of chitosan NPs.

NIR light-activated nanocomposites combat biofilm formation and enhance antibacterial efficacy for improved wound healing

Nanoparticle-based therapies are emerging as a pivotal frontier in biomedical research, showing their potential in combating infections and facilitating wound recovery. Herein, selenium-tellurium dopped copper oxide nanoparticles (SeTe-CuO NPs) with dual photodynamic and photothermal properties were synthesized, presenting an efficient strategy for combating bacterial infections. In vitro evaluations revealed robust antibacterial activity of SeTe-CuO NPs, achieving up to 99% eradication of bacteria and significant biofilm inhibition upon near-infrared (NIR) irradiation. Moreover, in vivo studies demonstrated accelerated wound closure upon treatment with NIR-activated SeTe-CuO NPs, demonstrating their efficacy in promoting wound healing. Furthermore, SeTe-CuO NPs exhibited rapid bacterial clearance within wounds, offering a promising solution for wound care. Overall, this versatile platform holds great promise for combating multidrug-resistant bacteria and advancing therapeutic interventions in wound management.

Preparation, stability, and antibacterial activity of carboxymethylated Anemarrhena asphodeloides polysaccharide-chitosan nanoparticles loaded curcumin

In present study, polysaccharide polyelectrolyte nanoparticles (CMAAP-CS NPs) were constructed by mixing carboxymethylated Anemarrhena asphodeloides polysaccharide (CMAAP) and chitosan (CS). CMAAP-CS NPs were applied as carrier to improve the bioavailability and stability of curcumin (Cur). The average particle size of CMAAP-CS NPs was 216.60 ± 4.21 nm and the entrapment efficiency of Cur reached 82.50 ± 2.09 %. The simulated digestion experiments in vitro confirmed that the bioavailability of Cur loaded in CMAAP-CS NPs was 59.84 ± 0.03 % after saliva, gastric and intestinal digestion, which was obvious higher than 21.57 ± 0.07 % of free Cur under the same conditions. The results of stability testing revealed that CMAAP-CS NPs could markedly reduce the degradation of Cur against storage, heating, UV light treatment, and neutral pH. This study provided promising polyelectrolyte complex loaded hydrophobic nutrients in medicine industry.

Optimize the parameters for the synthesis by the ionic gelation technique, purification, and freeze-drying of chitosan-sodium tripolyphosphate nanoparticles for biomedical purposes

BACKGROUND

Polymeric nanoparticles can be used for wound closure and therapeutic compound delivery, among other biomedical applications. Although there are several nanoparticle obtention methods, it is crucial to know the adequate parameters to achieve better results. Therefore, the objective of this study was to optimize the parameters for the synthesis, purification, and freeze-drying of chitosan nanoparticles. We evaluated the conditions of agitation speed, anion addition time, solution pH, and chitosan and sodium tripolyphosphate concentration.

RESULTS

Chitosan nanoparticles presented an average particle size of 172.8 ± 3.937 nm, PDI of 0.166 ± 0.008, and zeta potential of 25.00 ± 0.79 mV, at the concentration of 0.1% sodium tripolyphosphate and chitosan (pH 5.5), with a dripping time of 2 min at 500 rpm. The most representative factor during nanoparticle fabrication was the pH of the chitosan solution, generating significant changes in particle size and polydispersity index. The observed behavior is attributed to the possible excess of sodium tripolyphosphate during synthesis. We added the surfactants poloxamer 188 and polysorbate 80 to evaluate the stability improvement during purification (centrifugation or dialysis). These surfactants decreased coalescence between nanoparticles, especially during purification. The centrifugation increased the zeta potential to 40.8-56.2 mV values, while the dialyzed samples led to smaller particle sizes (152-184 nm). Finally, freeze-drying of the chitosan nanoparticles proceeded using two cryoprotectants, trehalose and sucrose. Both adequately protected the system during the process, and the sugar concentration depended on the purification process.

CONCLUSIONS

In Conclusion, we must consider each surfactant's benefits in formulations for selecting the most suitable. Also, it is necessary to do more studies with the molecule to load. At the same time, the use of sucrose and trehalose generates adequate protection against the freeze-drying process, even at a 5% w/v concentration. However, adjusting the percentage concentration by weight must be made to work with the CS-TPP NPs purified by dialysis.

Chitosan Nanoparticles Modified by Anredera cordifolia (Ten.) Steenis Leaf Extract for Enhancement of Azithromycin Encapsulation Efficiency and Loading Capacity: In vitro Drug Release Study

The encapsulation efficiency and the loading capacity of azithromycin (AZI) were succesfully enhanced by modifying chitosan nanoparticle (NCh) with Anredera cordifolia leaf extract (ACLE), as demonstrated in this study. The prominent secondary metabolites in ACLE could establish a new chemical bonds with NCh's amino groups and partly improved the hydrophobicity of NCh, which leads to excellent AZI encapsulation efficiency and loading capacity of 95.24 ± 1.30% and 55.74 ± 1.03%, respectively. TEM characterization demonstrated that the AZI-loaded ACLE-NCh nanoparticles were uniformly distributed with a particle size of 24.6 ± 2.9 nm. According to the result of in vitro drug release studies, AZI-loaded ACLE-NCh releases 1.12 ± 0.33% at a pH of 1.6 for 2 h, 82.05 ± 2.26% at a pH of 6.8 for 6 h, and 93.44 ± 1.94% at a pH of 7.4 for 24 h. It is remarkable that the encapsulation activityu of AZI-loaded ACLE-NCh is more effective due to the better interaction between NCh and AZI resulting from the increased hydrophobicity of modified NCh. Moreover, this work provides novel findings on the significant contribution of NCh modified by plant extracts, which has the potential as a carrier for azithromycin.

Scalable production of chitosan sub-micron particles by membrane ionotropic gelation process

Ionotropic gelation (IG) is a highly attractive method for the synthesis of natural water-soluble polymeric nanoparticles (NPs) and sub-micron particles (sMP) due to its relatively simple procedure and the absence of organic solvents. The method involves the electrostatic interaction between two ionic species of opposite charge. Although it is well studied at the laboratory scale, the difficulty to achieve size control in conventional bench-top process is actually a critical aspect of the technology. The aim of this work is to study the membrane dispersion technology in combination with IG as a suitable scalable method for the production of chitosan sub-micron particles (CS-sMPs). The two phases, one containing chitosan (CS) and the other containing sodium tripolyphosphate (TPP), were put in contact using a tubular hydrophobic glass membrane with a pore diameter of 1 μm. TPP (dispersed phase) was permeated through the membrane pores into the lumen side along which the CS solution (the continuous phase) flowed in batch recirculation or continuous single-pass operation mode. The influence of chemical variables (i.e. pH, concentration and mass ratio of polyelectrolyte species, emulsifier) and fluid-dynamic parameters (i.e. polyelectrolyte solution flow rate and their relative mass ratio) was studied to precisely tune the size of CS-Ps.

Anticancer Drug-Loaded Chitosan Nanoparticles for In Vitro Release, Promoting Antibacterial and Anticancer Activities

Targeted drug delivery to tumor cells may be possible using nanoparticles containing human therapeutic drugs. The present study was carried out to develop cisplatin (CP) and 5-fluorouracil (FA) encapsulated chitosan nanoparticles (CSNPs), crosslinked with sodium tripolyphosphate (TPP) by an ionic gelation method and in vitro release, promoting antibacterial and anticancer activities. The prepared CSNPs, before and after CP and FA encapsulation, have been studied using various characterization techniques such as FTIR, XRD, SEM, and TEM-SAED patterning. The composites were well-dispersed, with an average particle size diameter of about 395.3 ± 14.3 nm, 126.7 ± 2.6 nm, and 82.5 ± 2.3 nm, respectively. In vitro release studies indicated a controlled and sustained release of CP and FA from the CSNPs, with the release amounts of 72.9 ± 3.6% and 94.8 ± 2.9%. The antimicrobial activity of the CSNPs-FA (91.37 ± 4.37% and 89.28 ± 3.19%) showed a significantly better effect against E. coli and S. aureus than that shown by the CSNPs-CP (63.41 ± 3.84% and 57.62 ± 4.28%). The HCT-116 cell lines were selected for in vitro cell cytotoxicity and live/dead assay to evaluate the preliminary anticancer efficacy of the CSNPs-CP and CSNPs-FA towards successfully inhibiting the growth of cancer cells.

Growth patterns of Pseudomonas aeruginosa in milk fortified with chitosan and selenium nanoparticles during refrigerated storage

Pseudomonas spp are considered a common milk-associated psychotropic bacteria, leading to milk deterioration during storage; therefore, our study aimed to study the distribution of Pseudomonas aeruginosa in raw milk and its associated products then studying the growth behavior of P. aeruginosa in milk after employing chitosan nanoparticles (CsNPs 50, 25, and 15 mg/100ml) and selenium nanoparticles (SeNPs 0.5, 0.3 and 0.1 mg/100ml) as a trial to control the bacterial growth in milk during five days of cooling storage. Our study relies on the ion gelation method and green synthesis for the conversion of chitosan and selenium to nanosized particles respectively, we subsequently confirmed their shape using SEM and TEM. We employing Pseudomonas selective agar medium for monitoring the bacterial growth along the cooling storage. Our findings reported that high prevalence of Pseudomonas spp count in raw milk and kareish cheese and high incidence percent of P. aeruginosa in ice cream and yogurt respectively. Both synthesized nanoparticles exhibited antibacterial activity in a dose-dependent manner. Moreover, CsNPs50 could inhibit the P. aeruginosa survival growth to a mean average of 2.62 ± 1.18 log10cfu/ml in the fifth day of milk cooling storage; also, it was noted that the hexagonal particles SeNPs0.5 could inhibit 2.49 ± 11 log10cfu/ml in comparison to the control P. aeruginosa milk group exhibited growth survival rate 7.24 ± 2.57 log10cfu/ml under the same conditions. In conclusion, we suggest employing chitosan and selenium nanoparticles to improve milk safety and recommend future studies for the fate of nanoparticles in milk.

Green fabrication of chitosan nanoparticles using Lavendula angustifolia, optimization, characterization and in‑vitro antibiofilm activity

Chitosan nanoparticles (CNPs) are promising polymeric nanoparticles with exceptional physicochemical, antimicrobial and biological characteristics. The CNPs are preferred for a wide range of applications in the food industry, cosmetics, agriculture, medical, and pharmaceutical fields due to their biocompatibility, biodegradability, eco-friendliness, and non-toxicity. In the current study, a biologically based approach was used to biofabricate CNPs using an aqueous extract of Lavendula angustifolia leaves as a reducing agent. The TEM images show that the CNPs were spherical in shape and ranged in size from 7.24 to 9.77 nm. FTIR analysis revealed the presence of several functional groups, including C-H, C-O, CONH₂, NH₂, C-OH and C-O-C. The crystalline nature of CNPs is demonstrated by X-ray diffraction. The thermogravimetric analysis revealed that CNPs are thermally stable. The CNPs' surface is positively charged and has a Zeta potential of 10 mV. For optimising CNPs biofabrication, a face-centered central composite design (FCCCD) with 50 experiments was used. The artificial intelligence-based approach was used to analyse, validate, and predict CNPs biofabrication. The optimal conditions for maximum CNPs biofabrication were theoretically determined using the desirability function and experimentally verified. The optimal conditions that maximize CNPs biofabrication (10.11 mg/mL) were determined to be chitosan concentration 0.5%, leaves extract 75%, and initial pH 4.24. The antibiofilm activity of CNPs was evaluated in‑vitro. The results show that 1500 μg/mL of CNPs suppressed P. aeruginosa, S. aureus and C. albicans biofilm formation by 91.83 ± 1.71%, 55.47 ± 2.12% and 66.4 ± 1.76%; respectively. The promising results of the current study in biofilm inhibition by necrotizing biofilm architecture, reducing its significant constituents and inhibiting microbial cell proliferation encourage their use as natural biosafe and biocompatible anti-adherent coating in antibiofouling membranes, medical bandage/tissues and food packaging materials.

The correlation of molecule weight of chitosan oligomers with the corresponding viscosity and antibacterial activity

In order to explore the correlation between the viscosity of chitosan oligomers-acetic solution and its viscosity average molecular weight (M_v), and determine the M_v range with a strong bactericidal effect. A series of chitosan oligomers were obtained by degraded chitosan (728.5 kDa) with dilute acid and chitosan oligomer (101.5 kDa) was characterized by FT-IR, XRD, H NMR and C NMR. The bactericidal effect of chitosan oligomers with different Mv on E. coli, S. aureus and C. albicans was measured by plate counting method. And the bactericidal rate was taken as the evaluation indicator, the optimum conditions were determined by single-factor experiments. The result showed that the molecular structure of chitosan oligomers and original chitosan (728.5 kDa) were similar. The viscosity of the chitosan oligomers in acetic acid solution was positively correlated with the M_v, and the chitosan oligomers with the M_v of 52.5-145.0 kDa had a strong bactericidal performance. In addition, the bactericidal rate of chitosan oligomers on experimental strains was more than 90% when the concentration of 0.5 g/L (bacteria) and 1.0 g/L (fungi), pH6.0, incubation time of 30 min. Thus, chitosan oligomers had a potential application value when the M_v was in the range of 52.5-145.0 kDa.

Targeted pH-responsive chitosan nanogels with Tanshinone IIA for enhancing the antibacterial/anti-biofilm efficacy

Persistent bacterial infection caused by biofilms is one of the most serious problems that threatened human health. The development of antibacterial agents remains a challenge to penetrate biofilm and effectively treat the underlying bacterial infection. In the current study, chitosan-based nanogels were developed for encapsulating the Tanshinone IIA (TA) to enhance the antibacterial and anti-biofilm efficacy against Streptococcus mutans (S. mutans). The as-prepared nanogels (TA@CS) displayed excellent encapsulation efficiency (91.41 ± 0.11 %), uniform particle sizes (393.97 ± 13.92 nm), and enhanced positive potential (42.27 ± 1.25 mV). After being coated with CS, the stability of TA under light and other harsh environments was greatly improved. In addition, TA@CS displayed pH responsiveness, allowing it to selectively release more TA in acidic conditions. Furthermore, the positively charged TA@CS were equipped to target negatively charged biofilm surfaces and efficiently penetrate through biofilm barriers, making it promising for remarkable anti-biofilm activity. More importantly, when TA was encapsulated into CS nanogels, the antibacterial activity of TA was enhanced at least 4-fold. Meanwhile, TA@CS inhibited 72 % of biofilm formation at 500 μg/mL. The results demonstrated that the nanogels constituted CS and TA had antibacterial/anti-biofilm properties with synergistic enhanced effects, which will benefit pharmaceutical, food, and other fields.

Preparation, Characterization and Antibacterial Property Analysis of Cellulose Nanocrystals (CNC) and Chitosan Nanoparticles Fine-Tuned Starch Film

To improve the mechanical and antibacterial properties of traditional starch-based film, herein, cellulose nanocrystals (CNCs) and chitosan nanoparticles (CS NPs) were introduced to potato starch (PS, film-forming matrix) for the preparation of nanocomposite film without incorporation of additional antibacterial agents. CNCs with varied concentrations were added to PS and CS NPs composite system to evaluate the optimal film performance. The results showed that tensile strength (TS) of nanocomposite film with 0, 0.01, 0.05, and 0.1% (w/w) CNCs incorporation were 41, 46, 47 and 41 MPa, respectively. The elongation at break (EAB) reached 12.5, 10.2, 7.1 and 13.3%, respectively. Due to the reinforcing effect of CNCs, surface morphology and structural properties of nanocomposite film were altered. TGA analysis confirmed the existence of hydrogen bondings and electrostatic attractions between components in the film-forming matrix. The prepared nanocomposite films showed good antibacterial properties against both E. coli and S. aureus. The nanocomposite film, consist of three most abundant biodegradable polymers, could potentially serve as antibacterial packaging films with strong mechanical properties for food and allied industries.

Chitosan-alginate nanoparticles of cabazitaxel: Design, dual-receptor targeting and efficacy in lung cancer model

Cabazitaxel (CZT) loaded chitosan-alginate based (CSA) nanoparticles were developed with dual targeting functions of both folate receptor and epidermal growth factor receptor (EGFR) using ionic gelation technique. The chitosan-folate conjugate was synthesized, and characterized by using FTIR, NMR and Mass spectroscopy. The physicochemical parameters and morphology of all CSA nanoparticles were examined. The degree of conjugation of folic acid and cetuximab (CTXmab) was determined by UV-Visible spectroscopy and Bradford assay, respectively. Moreover, XPS analysis also supported the presence of the ligands on nanoparticles. The cellular-uptake study performed on A-549 cells demonstrated a significant enhancement in the uptake of dual-receptor targeted CSA nanoparticles than non-targeted and single-receptor targeted CSA nanoparticles. Further, CZT-loaded dual receptors targeted CSA nanoparticles also showed significantly lower IC50 values (~38 folds) than the CZT control against A-549 cells. Further, in-vivo histopathological evaluations of dual receptor-targeted CSA nanoparticles have demonstrated better safety in Wistar rats. Moreover, its treatment on the Benzo(a)pyrene (B(a)P) induced lung cancer mice model has showed the enhanced anticancer efficacy of CZT with a prolonged survival rate.

Customizing nano-chitosan for sustainable drug delivery

Chitosan is a natural polymer with acceptable biocompatibility, biodegradability, and mechanical stability; hence, it has been widely appraised for drug and gene delivery applications. However, there has been no comprehensive assessment to tailor-make chitosan cross-linkers of various types and functionalities as well as complex chitosan-based semi- and full-interpenetrating networks for drug delivery systems (DDSs). Herein, various fabrication methods developed for chitosan hydrogels are deliberated, including chitosan crosslinking with and without diverse cross-linkers. Tripolyphosphate, genipin and multi-functional aldehydes, carboxylic acids, and epoxides are common cross-linkers used in developing biomedical chitosan for DDSs. Methods deployed for modifying the properties and performance of chitosan hydrogels, via their composite production (semi- and full-interpenetrating networks), are also cogitated here. In addition, recent advances in the fabrication of advanced chitosan hydrogels for drug delivery applications such as oral drug delivery, transdermal drug delivery, and cancer therapy are discussed. Lastly, thoughts on what is needed for the chitosan field to continue to grow is also debated in this comprehensive review article.

Simultaneous loading of (-)-epigallocatechin gallate and ferulic acid in chitosan-based nanoparticles as effective antioxidant and potential skin-whitening agents

Chitosan (CS) based nanoparticles simultaneously loaded with (-)-epigallocatechin gallate (EGCG) and ferulic acid (FA) were fabricated via ionic gelation method modified by sodium tripolyphosphate and genipin (G-CS-EGCG-FA NPs). The particle size, morphology, entrapment efficiency, rheological properties, antioxidant and tyrosinase inhibitory activity of NPs were investigated. The G-CS-EGCG-FA NPs exhibited irregular ellipsoidal shape with average diameter of 412.3 nm and high DPPH and ABTS·⁺ scavenging ability. The entrapment efficiency of EGCG and FA in NPs was 46.0 ± 1.3 % and 46.8 ± 1.6 %, respectively. CS-based NPs show no toxic effects on NIH 3 T3 cells and B16-F10 melanoma cells with concentration <200 μg/mL and 25 μg/mL, respectively and the cell viability ranged from 100 % to 118 %. Meanwhile, the oxidative repaired capacity of G-CS-EGCG-FA NPs (200 μg/mL) in H₂O₂-induced cells was over 100 %, higher than that of the same dose of free EGCG or FA. Moreover, the tyrosinase inhibition activity of G-CS-EGCG-FA NPs (25 μg/mL) (84.6 %) was more potent than that of free EGCG (55.3 %), free FA (47.1 %) and kojic acid, indicating the good skin repairing and whitening ability of G-CS-EGCG-FA NPs. Given these results, this research provides new insights for designing novel particles loaded with dual bioactive agents that possess synergistic benefits.

Chitin Nanocrystal Hydrophobicity Adjustment by Fatty Acid Esterification for Improved Polylactic Acid Nanocomposites

Bioplastics may solve environmental issues related to the current linear plastic economy, but they need improvement to be viable alternatives. To achieve this, we aimed to add chitin nanocrystals (ChNC) to polylactic acid (PLA), which is known to alter material properties while maintaining a fully bio-based character. However, ChNC are not particularly compatible with PLA, and surface modification with fatty acids was used to improve this. We used fatty acids that are different in carbon chain length (C4–C18) and degree of saturation (C18:2). We successfully used Steglich esterification and confirmed covalent attachment of fatty acids to the ChNC with FTIR and solid-state ¹³C NMR. The morphology of the ChNC remained intact after surface modification, as observed by TEM. ChNC modified with C4 and C8 showed higher degrees of substitution compared to fatty acids with a longer aliphatic tail, while particles modified with the longest fatty acid showed the highest hydrophobicity. The addition of ChNC to the PLA matrix resulted in brown color formation that was reduced when using modified particles, leading to higher transparency, most probably as a result of better dispersibility of modified ChNC, as observed by SEM. In general, addition of ChNC provided high UV-protection to the base polymer material, which is an additional feature that can be created through the addition of ChNC, which is not at the expense of the barrier properties, or the mechanical strength.

Ultrasound-assisted preparation of chitosan/nano-silica aerogel/tea polyphenol biodegradable films: Physical and functional properties

In this study, chitosan(CS), nano-silicon aerogels(nSA) and tea polyphenols(TP) were used as film-forming materials and processed with ultrasonication to form films using the tape-casting method. The effects of ultrasonication time, temperature and frequency on the properties of CS/nSA/TP film were explored via material property testing. The results of response surface showed that the maximum tensile strength of the film was 4.036 MPa at ultrasonication time(57.97 min), temperature(37.26 °C) and frequency(30 kHz). The maximum elongation at break of the film was 279.42 % at ultrasonication time(60.88 min), temperature(39.93 °C) and frequency(30 kHz). Due to cavitation and super-mixing effects, ultrasonication may make the surface of the film smoother and easier to degrade. After ultrasonication, TPs were protected by the 3D network structure composed of CS and nSA. Ultrasonication improved the antioxidant and antibacterial properties of the film. These results show that ultrasonication is an effective method to improve the properties of films.

Recent Advances in Antimicrobial Nano-Drug Delivery Systems

Infectious diseases are among the major health issues of the 21st century. The substantial use of antibiotics over the years has contributed to the dissemination of multidrug resistant bacteria. According to a recent report by the World Health Organization, antibacterial (ATB) drug resistance has been one of the biggest challenges, as well as the development of effective long-term ATBs. Since pathogens quickly adapt and evolve through several strategies, regular ATBs usually may result in temporary or noneffective treatments. Therefore, the demand for new therapies methods, such as nano-drug delivery systems (NDDS), has aroused huge interest due to its potentialities to improve the drug bioavailability and targeting efficiency, including liposomes, nanoemulsions, solid lipid nanoparticles, polymeric nanoparticles, metal nanoparticles, and others. Given the relevance of this subject, this review aims to summarize the progress of recent research in antibacterial therapeutic drugs supported by nanobiotechnological tools.

Enhanced antibacterial activity of lysozyme loaded quaternary ammonium chitosan nanoparticles functionalized with cellulose nanocrystals

In this study, cellulose nanocrystals (CNC) as functional cross-linker and Pickering emulsifier was used to stabilize Lysozyme (Lys) encapsulated in quaternary ammonium chitosan nanoparticles (QC NPs) via ionic gelation method. Physicochemical, structural, and antibacterial properties of the CNC stabilized Lys loaded QC NPs were also evaluated. Particle size, particle size distribution, Zeta potential (ZP), and spectroscopic analyses showed the successful encapsulation of Lys. Antibacterial activity of NPs against Staphylococcus aureus and Vibrio parahaemolyticus was investigated on the basis of inhibition zone (IZ), minimum inhibitory concentration (MIC), and minimum bacterial concentration (MBC). MIC and MBC of CNC stabilized Lys loaded HQC NPs against S. aureus were 0.094 and 0.188 while corresponding values for CNC stabilized Lys loaded LQC NPs V. parahaemolyticus were 0.156 and 0.312 mg/mL, respectively. Therefore, CNC stabilized Lys loaded QC NPs have potential implications in the food industry for food preservation and packaging.

Investigation of the Characteristics and Antibacterial Activity of Polymer-Modified Copper Oxide Nanoparticles

The proliferation of drug-resistant pathogens continues to increase, giving rise to serious public health concerns. Many researchers have formulated metal oxide nanoparticles for use as novel antibacterial agents. In the present study, copper oxide (CuO) was synthesized by simple hydrothermal synthesis, and doping was performed to introduce different polymers onto the NP surface for bacteriostasis optimization. The polymer-modified CuO NPs were analyzed further with XRD, FTIR, TEM, DLS and zeta potential to study their morphology, size, and the charge of the substrate. The results indicate that polymer-modified CuO NPs had a significantly higher bacteriostatic rate than unmodified CuO NPs. In particular, polydopamine (PDA)-modified CuO (CuO-PDA) NPs, which carry a weakly negative surface charge, exhibited excellent antibacterial effects, with a bacteriostatic rate of up to 85.8 ± 0.2% within 3 h. When compared to other polymer-modified CuO NPs, CuO-PDA NPs exhibited superior bacteriostatic activity due to their smaller size, surface charge, and favorable van der Waals interactions. This may be attributed to the fact that the CuO-PDA NPs had relatively lipophilic structures at pH 7.4, which increased their affinity for the lipopolysaccharide-containing outer membrane of the Gram-negative bacterium Escherichia coli.

Preparation, characterization and biological activity of proanthocyanidin-chitosan nanoparticles

In this study, proanthocyanidin-loaded chitosan nanoparticles (PC-CS-NPs) were produced using ionotropic gelation and characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and dynamic light scattering (DLS). The synthesized nanoparticles were smaller than 300 nm and had a spherical shape, smooth topography and homogenous morphology as observed through scanning electron microscopy (SEM). In vitro release study showed that proanthocyanidins (PC) had a sustainable release from PC-CS-NPs in different buffer media. PC-CS-NPs had higher or comparable potency in scavenging DPPH and ABTS free radicals as compared to native drugs. Furthermore, PC-CS-NPs also inhibited the growth of four bacteria species, whose degree of inhibition depended on the bacterial strain. The results of SEM confirmed the changes in the microstructure of bacteria. Our findings support the use of chitosan nanoparticles to encapsulate PC and improve its bioactivity in food products.

Application of Electrospinning in Antibacterial Field

In recent years, electrospun nanofibers have attracted extensive attention due to their large specific surface area, high porosity, and controllable shape. Among the many applications of electrospinning, electrospun nanofibers used in fields such as tissue engineering, food packaging, and air purification often require some antibacterial properties. This paper expounds the development potential of electrospinning in the antibacterial field from four aspects: fiber morphology, antibacterial materials, antibacterial mechanism, and application fields. The effects of fiber morphology and antibacterial materials on the antibacterial activity and characteristics are first presented, then followed by a discussion of the antibacterial mechanisms and influencing factors of these materials. Typical application examples of antibacterial nanofibers are presented, which show the good prospects of electrospinning in the antibacterial field.

Engineering Carbohydrate-Based Particles for Biomedical Applications: Strategies to Construct and Modify

Carbohydrate-based micro/nanoparticles have gained significant attention for various biomedical applications such as targeted/triggered/controlled drug delivery, bioimaging, biosensing, etc., because of their prominent characteristics like biocompatibility, biodegradability, hydrophilicity, and nontoxicity as well as nonimmunogenicity. Most importantly, the ability of the nanoparticles to recognize specific cell sites by targeting cell surface receptors makes them a promising candidate for designing a targeted drug delivery system. These particles may either comprise polysaccharides/glycopolymers or be integrated with various polymeric/inorganic nanoparticles such as gold, silver, silica, iron, etc., to reduce the toxicity of the inorganic nanoparticles and thus facilitate their cellular insertion. Various synthetic methods have been developed to fabricate carbohydrate-based or carbohydrate-conjugated inorganic/polymeric nanoparticles. In this review, we have highlighted the recently developed synthetic approaches to afford carbohydrate-based particles along with their significance in various biomedical applications.

In Vitro Antiprotozoal Effects of Nano-chitosan on Plasmodium falciparum, Giardia lamblia and Trichomonas vaginalis

BACKGROUND

Treatment of parasitic infections with conventional drugs is associated with high toxicity, and undesirable side effects require cogent substitutions. Nanotechnology has provided novel approaches to synthesize nano-drugs to improve efficient antipathetic treatment.

PURPOSE

Nano-chitosan as a nontoxic antimicrobial agent was examined against three most prevalent protozoa in humans, Plasmodium falciparum, Giardia lamblia and Trichomonas vaginalis.

METHODS

Chitosan extracted from Penicillium fungi was converted to nanoparticles to maximize its therapeutic properties. Safety of nano-chitosan was examined by determining its hemolytic property and toxicity on PC12 cells. The studied parasites were identified with RFLP-PCR and cultivation in relevant media. Characteristics of nano-chitosan as an useful and valuable curative compound was evaluated by FTIR, DLS and SEM. Dose dependent anti-parasitic effect of nano-chitosan was evaluated.

RESULTS

The highest anti-parasitic activity of the nano-chitosan was observed at 50 μg/mL by which growth rates of cultivated P. falciparum, T. vaginalis and G. lamblia were inhibited by 59.5%, 99.4%, and 31.3%, respectively. The study demonstrated that nano-chitosan with the least toxicity, low side effects, and substantial efficacy deserved to be considered as an anti-parasitic nano-compound.

CONCLUSION

Nano-chitosan significantly inhibited protozoan growth in vitro promising to explore its use to combat parasitic infections. Further investigations covering extended sample size, in vivo experiments and optimizing the concentration used may lead to efficient treatment of protozoan diseases.

Investigation of the structural, physical properties, antioxidant, and antimicrobial activity of chitosan- nano-silicon aerogel composite edible films incorporated with okara powder

The chitosan/okra powder/nano-silicon aerogel composite films were prepared by casting method and their physicochemical properties and structural characterization were studied. The results showed that the composite film had good mechanical properties, barrier properties and optical properties. The composite film has strong flexibility. The surface glossiness of C/D/S1.5:1:0.1 film was 14.4Gu. As for the antibacterial activity, all the composite films had strong antibacterial activity against Gram-negative (E. coli) and Gram-positive (S. aureus), and the inhibition zone of C/D/S1.5:1:0.10 against E. coli reached 551.96 mm2, the inhibition zone for S. aureus was 350.29 mm2. The composite film had uniform, non-porous, continuous and dense surface characteristics. The structural characterization confirmed that there was good compatibility between chitosan, okara powder and nano-silicon aerogel. In summary, the composite films had excellent performance and structure, which promoted the research of functional packaging films.

New Opportunity to Formulate Intranasal Vaccines and Drug Delivery Systems Based on Chitosan

In an attempt to develop drug delivery systems that bypass the blood–brain barrier (BBB) and prevent liver and intestinal degradation, it was concluded that nasal medication meets these criteria and can be used for drugs that have these drawbacks. The aim of this review is to present the influence of the properties of chitosan and its derivatives (mucoadhesion, permeability enhancement, surface tension, and zeta potential) on the development of suitable nasal drug delivery systems and on the nasal bioavailability of various active pharmaceutical ingredients. Interactions between chitosan and proteins, lipids, antigens, and other molecules lead to complexes that have their own applications or to changing characteristics of the substances involved in the bond (conformational changes, increased stability or solubility, etc.). Chitosan and its derivatives have their own actions (antibacterial, antifungal, immunostimulant, antioxidant, etc.) and can be used as such or in combination with other molecules from the same class to achieve a synergistic effect. The applicability of the properties is set out in the second part of the paper, where nasal formulations based on chitosan are described (vaccines, hydrogels, nanoparticles, nanostructured lipid carriers (NLC), powders, emulsions, etc.).

Evaluation of new environmental friendly particulate soil fertilizers based on agroindustry wastes biopolymers and sugarcane vinasse

This study evaluated the physicochemical and morphological properties of pectin and chitosan particles combined with sugarcane vinasse for soil fertilization applications. Particles were obtained by adding the biopolymeric solutions (pectin or chitosan solution) dropwise into the crosslinking solutions (calcium chloride 1% in ethanolic solution or tripolyphosphate 5% aqueous solution) followed by drying. Vinasse enhanced pectin gel stability improving pectin/vinasse particle properties. Physicochemical characterization indicated that vinasse nutrients were properly incorporated in both pectin and chitosan matrices. Particles showed spherical shape, with an average diameter of 3 and 2 mm for the pectin and chitosan particles with vinasse, respectively. Chitosan particles, compared to pectin, showed lower swelling capacity and solubility and higher mechanical resistance indicating a denser and more compact polymer network. Both particles were able to hinder water evaporation rates from sandy soil under water stress conditions. Biobased particles with vinasse added show potential to be applied as soil fertilizer representing an alternative to use and disposal of this expressive wastewater from sugar and alcohol industries.

Enzymatic Modifications of Chitin, Chitosan, and Chitooligosaccharides

Chitin and its N-deacetylated derivative chitosan are two biological polymers that have found numerous applications in recent years, but their further deployment suffers from limitations in obtaining a defined structure of the polymers using traditional conversion methods. The disadvantages of the currently used industrial methods of chitosan manufacturing and the increasing demand for a broad range of novel chitosan oligosaccharides (COS) with a fully defined architecture increase interest in chitin and chitosan-modifying enzymes. Enzymes such as chitinases, chitosanases, chitin deacetylases, and recently discovered lytic polysaccharide monooxygenases had attracted considerable interest in recent years. These proteins are already useful tools toward the biotechnological transformation of chitin into chitosan and chitooligosaccharides, especially when a controlled non-degradative and well-defined process is required. This review describes traditional and novel enzymatic methods of modification of chitin and its derivatives. Recent advances in chitin processing, discovery of increasing number of new, well-characterized enzymes and development of genetic engineering methods result in rapid expansion of the field. Enzymatic modification of chitin and chitosan may soon become competitive to conventional conversion methods.

The Effect of Nanofillers on the Functional Properties of Biopolymer-based Films: A Review

Waste from non-degradable plastics is becoming an increasingly serious problem. Therefore, more and more research focuses on the development of materials with biodegradable properties. Bio-polymers are excellent raw materials for the production of such materials. Bio-based biopolymer films reinforced with nanostructures have become an interesting area of research. Nanocomposite films are a group of materials that mainly consist of bio-based natural (e.g., chitosan, starch) and synthetic (e.g., poly(lactic acid)) polymers and nanofillers (clay, organic, inorganic, or carbon nanostructures), with different properties. The interaction between environmentally friendly biopolymers and nanofillers leads to the improved functionality of nanocomposite materials. Depending on the properties of nanofillers, new or improved properties of nanocomposites can be obtained such as: barrier properties, improved mechanical strength, antimicrobial, and antioxidant properties or thermal stability. This review compiles information about biopolymers used as the matrix for the films with nanofillers as the active agents. Particular emphasis has been placed on the influence of nanofillers on functional properties of biopolymer films and their possible use within the food industry and food packaging systems. The possible applications of those nanocomposite films within other industries (medicine, drug and chemical industry, tissue engineering) is also briefly summarized.