Preparation of chitosan/tripolyphosphate nanoparticles with highly tunable size and low polydispersity

In vitro and in vivo evaluation of tedizolid nanoparticle incorporated buccal films for oromucosal infections

A novel tedizolid phosphate (TZP) nanoparticle (NP)-loaded buccal film formulation was developed for the treatment of buccal wounds infected with S. aureus. TZP-loaded chitosan NPs were produced and characterized to prepare this composite system. The optimum NP formulation was then loaded into mucoadhesive buccal films. The antibacterial effects of the obtained buccal films were evaluated by in vitro and in vivo studies. The optimum TZP-NP formulation (F8) had a particle size of 177.40 ± 2.97 nm and PDI and ZP values were 0.437 ± 0.002 and 33.9 ± 0.5, respectively. In antibacterial efficacy tests, the optimum NP containing buccal film formulation was used, which released approximately 90 % of TZP within 5 h. TZP-NP-loaded buccal films achieved a 3 log10 reduction in S. aureus within just 3 h. It was also administered to Wistar albino rats with S. aureus-infected buccal wounds. As a result of in vivo studies, a significant decrease in the number of S. aureus was detected in wound samples treated with TZP-NP-loaded buccal films. In addition, a complete inhibition of growth was observed on the fifth day of the film application. The current work suggested that the TZP-NP-loaded composite films could be promising candidates for effective and long-acting antibacterial treatment of buccal wounds.

Antimicrobial Effect of Chitosan Nanoparticles and Allium Species on Mycobacterium tuberculosis and Several Other Microorganisms

This study evaluates the antimicrobial efficacy of chitosan nanoparticles (CNPs), varying in size, against clinical isolates of Mycobacterium tuberculosis (MTB), E. coli, S. aureus, E. faecalis, and C. albicans, as well as the antimicrobial effects of aqueous extracts and lyophilized powders of Allium (garlic) species. CNPs were synthesized through ionotropic gelation and characterized by Z potential, hydrodynamic diameter (dynamic light scattering, DLS), and SEM. Aqueous garlic extracts were prepared via decoction. We assessed antimicrobial activity using disk diffusion and broth microdilution methods; in addition, a modified agar proportion method in blood agar was used for antimicrobial activity against MTB. CNPs inhibited MTB growth at 300 μg for 116.6 nm particles and 400 μg for 364.4 nm particles. The highest antimicrobial activity was observed against E. faecalis with nanoparticles between 200 and 280 nm. Allium sativum extract produced inhibition for C. albicans at 100 μg. The results indicate that CNPs possess significant antimicrobial properties against a range of pathogens, including MTB, at high concentrations. On the other hand, aqueous Allium sativum extracts exhibited antimicrobial activity. Nonetheless, due to their instability in solution, the use of lyophilized Allium sativum powder is preferable.

Microencapsulation, Physicochemical Characterization, and Antioxidant, Antibacterial, and Antiplasmodial Activities of Holothuria atra Microcapsule

This study provides the design of a microencapsulation formula, physicochemical characterization, and antioxidant, antibacterial, and antiplasmodial activities of Holothuria atra microcapsules. The ethanolic extract of H. atra was microencapsulated with chitosan (CHI) and sodium tripolyphosphate (Na-TPP) with various stirring times: 60 minutes (CHI60), 90 minutes (CHI90), and 120 minutes (CHI120). The microcapsules were then observed for physicochemical properties using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The microcapsules were tested for antioxidant activity and antibacterial activity against Staphylococcus aureus and Escherichia coli using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. Antiplasmodial bioactivity was assessed through in silico molecular docking. The CHI60 and CHI120 microcapsules exhibited a smaller size and an irregular spherical shape, while the same FTIR profile was observed in CHI90 and CHI120. The bioactivity tests demonstrated that CHI90 exhibited high antibacterial activity against E. coli and S. aureus, while CHI120 exhibited high antioxidant performance. Calcigeroside B and Echinoside B exhibited antiplasmodial activity against the Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) protein, along with an artemisinin inhibition mechanism. In conclusion, the microcapsules with the CHI90 formula demonstrated the best antibacterial activity, while the CHI120 formula exhibited high antioxidant activity. Two terpenoids, Calcigeroside B and Echinoside B, exhibited the best antiplasmodial activity.

Exploring the antimicrobial potential of chitosan nanoparticles: synthesis, characterization and impact on Pseudomonas aeruginosa virulence factors

The escalating antibiotic resistance observed in bacteria poses a significant threat to society, with the global prevalence of resistant strains of Pseudomonas aeruginosa on the rise. Addressing this challenge necessitates exploring strategies that would complement existing antimicrobial agents, e.g. by substances mitigating bacterial virulence without eliciting selective pressure for resistance emergence. In this respect, free-form chitosan has demonstrated promising efficacy, prompting our investigation into reinforcing its effects through nanoparticle formulations. Our study focuses on the preparation of chitosan nanoparticles under suitable conditions while emphasizing the challenges associated with stability that can affect biological activity. These challenges are mitigated by introducing quaternized chitosan, which ensures colloidal stability in the culture media. Our approach led to the production of trimethylchitosan nanoparticles with a median size of 103 nm, circularity of 0.967, and a charge of 14.9 ± 3.1 mV, stable within a one-month period in a water stock solution, showing promising attributes for further valorization. Furthermore, the study delves into the antimicrobial activity of trimethylchitosan nanoparticles on Pseudomonas aeruginosa and confirms the benefits of both nanoformulation and modification of chitosan, as our prepared nanoparticles inhibit 50% of the bacterial population at concentration ≥160 mg L-1 within tested strains. Additionally, we identified a concentration of 5 mg L-1 that no longer impedes bacterial growth, allowing reliable verification of the effect of the prepared nanoparticles on Pseudomonas aeruginosa virulence factors, including motility, protease activity, hemolytic activity, rhamnolipids, pyocyanin, and biofilm production. Although trimethylchitosan nanoparticles exhibit promise as an effective antibiofilm agent (reducing biofilm development by 50% at concentrations ranging from 80 to 160 mg L-1) their impact on virulence manifestation is likely not directly associated with quorum sensing. Instead, it can probably be attributed to non-specific interactions with the bacterial surface. This exploration provides valuable insights into the potential of quaternized chitosan nanoparticles in addressing Pseudomonas aeruginosa infections and underscores the multifaceted nature of their antimicrobial effects.

Pickering emulsions stabilized by starch nanocrystals prepared from various crystalline starches by ultrasonic assisted acetic acid: Stability and delivery of curcumin

Ultrasonic assisted acetic acid hydrolysis was applied to prepare starch nanocrystals (SNCs) from native starches with different crystalline structures (A, B, and C types). The structure properties, morphology, Pickering emulsion stability and curcumin deliver capacity of both SNCs and native starches were investigated and compared. Compared with native starches, SNCs showed smaller size and higher crystallinity. The size of SNCs varied with different crystalline types, with C-type starch exhibiting the smallest SNCs (107.4 nm), followed by A-type (113.8 nm), and B-type displaying the largest particle size (149.0 nm). SNCs-Pickering emulsion showed enhanced stability with smaller emulsion droplets, higher static stability, and denser oil/water interface. SNCs-Pickering emulsions displayed higher curcumin loading efficiency (53.53 %-61.41 %) compared with native starch-Pickering emulsions (13.93 %-19.73 %). During in vitro digestion, SNCs-Pickering emulsions proved to be more proficient in protecting and prolonging the biological activity of curcumin due to their smaller size and better interfacial properties. These findings demonstrated the potential of SNCs for application in Pickering emulsion and delivery of bioactive components.

Modeling and characterization of lenalidomide-loaded tripolyphosphate-crosslinked chitosan nanoparticles for anticancer drug delivery

Tripolyphosphate-crosslinked chitosan (TPPCS) nanoparticles were employed in the encapsulation of lenalidomide (LND) using a straightforward ionic cross-linking approach. The primary objectives of this technique were to enhance the bioavailability of LND and mitigate inadequate or overloading of hydrophobic and sparingly soluble drug towards cancer cells. In this context, a quantum chemical model was employed to elucidate the characteristics of TPPCS nanoparticles, aiming to assess the efficiency of these nanocarriers for the anticancer drug LND. Fifteen configurations of TPPCS and LND (TPPCS /LND1-15) were optimized using B3LYP density functional level of theory and PCM model (H2O). AIM analysis revealed that the high drug loading capacity of TPPCS can be attributed to hydrogen bonds, as supported by the average binding energy (168 kJ mol-1). The encouraging theoretical results prompted us to fabricate this drug delivery system and characterize it using advanced analytical techniques. The encapsulation efficiency of LND within the TPPCS was remarkably high, reaching approximately 87 %. Cytotoxicity studies showed that TPPCS/LND nanoparticles are more effective than the LND drug. To sum up, TPPCS/LND nanoparticles improved bioavailability of poorly soluble LND through cancerous cell membrane. In light of this accomplishment, the novel drug delivery route enhances efficiency, allowing for lower therapy doses.

A review of chitosan in gene therapy: Developments and challenges

Gene therapy, as a revolutionary treatment, has been gaining more and more attention. The key to gene therapy is the selection of suitable vectors for protection of exogenous nucleic acid molecules and enabling their specific release in target cells. While viral vectors have been widely used in researches, non-viral vectors are receiving more attention due to its advantages. Chitosan (CS) has been widely used as non-viral organic gene carrier because of its good biocompatibility and its ability to load large amounts of nucleic acids. This paper summarizes and evaluates the potential of chitosan and its derivatives as gene delivery vector materials, along with factors influencing transfection efficiency, performance evaluation, ways to optimize infectious efficiency, and the current main research development directions. Additionally, it provides an outlook on its future prospects.

Preparation, Characterization, and Anticancer Activity Assessment of Chitosan/TPP Nanoparticles Loaded with Echis carinatus Venom

AIMS AND BACKGROUND

Echis carinatus venom is a toxic substance naturally produced by special glands in this snake species. Alongside various toxic properties, this venom has been used for its therapeutic effects, which are applicable in treating various cancers (liver, breast, etc.).

OBJECTIVE

Nanotechnology-based drug delivery systems are suitable for protecting Echis carinatus venom against destruction and unwanted absorption. They can manage its controlled transfer and absorption, significantly reducing side effects.

METHODS

In the present study, chitosan nanoparticles were prepared using the ionotropic gelation method with emulsion cross-linking. The venom's encapsulation efficiency, loading capacity, and release rate were calculated at certain time points. Moreover, the nanoparticles' optimal formulation and cytotoxic effects were determined using the MTT assay.

RESULTS

The optimized nanoparticle formulation increases cell death induction in various cancerous cell lines. Moreover, chitosan nanoparticles loaded with Echis carinatus venom had a significant rate of cytotoxicity against cancer cells.

CONCLUSION

It is proposed that this formulation may act as a suitable candidate for more extensive assessments of cancer treatment using nanotechnology-based drug delivery systems.

Pickering emulsions stabilized by chitosan-flaxseed gum-hyaluronic acid nanoparticles for controlled topical release of ferulic acid

Chitosan (CS) based nanoparticles (NPs) were fabricated via an ionic gelation reaction modified by flaxseed gum (FG) or sodium tripolyphosphate (STPP). The average particle size, morphology, interfacial tension, and wettability of NPs were characterized. The particle size of CS-STPP-HA (hyaluronic acid)-FA (ferulic acid) NPs and CS-FG-HA-FA NPs was 400.8 nm and 262.4 nm, respectively under the optimized conditions of CS/STPP = 5:1 (w/w) or CS/FG = 1:1 (v/v) with HA concentration of 0.25 mg/mL and FA dosage of 25 μM. FG acted as a good alternative for STPP to form particles with CS in stabilizing Pickering emulsion with an internal diacylglycerol (DAG) phase of 50-80 % (v/v). The complex nanoparticles had high surface activity and contact angle close to 90 °C, being able to tightly packed at the droplet surface. The emulsions had high thermal, ionic and oxidative stability. With the aid of moisturizing polysaccharides and DAG oil, the emulsions had a good sustained-release ability for FA with deeper penetration and retention into the dermis of the skin. Thus, FG and HA-based NPs serve as green vehicles for the fabrication of novel Pickering emulsions and possess great potential to be applied as a delivery system for lipophilic active agents in functional food and cosmetic products.

Preparation, characterization, and in vitro cytotoxicity activity of allyl-isothiocyanate-embedded polymeric nanoparticles for potential breast cancer targeting

BACKGROUND

Allyl isothiocyanate (AITC) is an excellent active phytoconstituent recently revealed for cancer treatment. The strategic prominence of this study was to synthesize and characterize AITC-embedded tripolyphosphate-modified chitosan nanoparticles (AITC@CS-TPP-NPs) by ionic gelation.

METHOD

Chitosan is recycled as a polymer to fabricate AITC@CS-TPP-NPs; the fabricated nanoparticles (NPs) are then characterized using FT-IR spectroscopy, DSC, XRD, zeta potential, size analysis, SEM, EDX, entrapment efficiency, in vitro drug release study, and in vitro cytotoxicity activity against MCF-7 to explore the effectiveness and strength.

RESULTS

As a result, developed AITC@CS-TPP-NPs demonstrates good stability with a zeta potential of 35.83 mV and 90.14% of drug release. The anticancer potential of AITC@CS-TPP-NPs shows the improved cytotoxicity activity of AITC due to the surface modification of CS using TPP. Hence, the cytotoxicity of AITC@CS-TPP-NPs was tested in vitro against a human breast cancer cell line (MCF-7) and found to be considerable.

CONCLUSION

The AITC@CS-TPP-NPs were effectively synthesized and have significant benefits, including being easy to prepare, stable, and affordable with wide use in human breast cancer against cell line (MCF-7).

Sustainable functionalized chitosan based nano-composites for wound dressings applications: A review

Functionalized chitosan nanocomposites have been studied for wound dressing applications due to their excellent antibacterial and anti-fungal properties. Polysaccharides show excellent antibacterial and drug-release properties and can be utilized for wound healing. In this article, we comprise distinct approaches for chitosan functionalization, such as photosensitizers, dendrimers, graft copolymerization, quaternization, acylation, carboxyalkylation, phosphorylation, sulfation, and thiolation. The current review article has also discussed brief insights on chitosan nanoparticle processing for biomedical applications, including wound dressings. The chitosan nanoparticle preparation technologies have been discussed, focusing on wound dressings owing to their targeted and controlled drug release behavior. The future directions of chitosan research include; a) finding an effective solution for chronic wounds, which are unable to heal completely; b) providing effective wound healing solutions for diabetic wounds and venous leg ulcers; c) to better understanding the wound healing mechanism with such materials which can help provide the optimum solution for wound dressing; d) to provide an improved treatment option for wound healing.

Loratadine oral bioavailability enhancement via solid dispersion loaded oro-dispersible films: Formulation, characterization and pharmacokinetics

Loratadine (LRD) belongs to second-generation tricyclic H1 antihistamine class, known for its non-sedating properties in allergic reactions. H1 antihistamines avoid and block the responses to allergens or histamine in nose and conjunctivae, thereby abolishing itching, congestion and sneezing. LRD is a Biopharmaceutical Class System (BCS) class II drug with dissolution or solubility limited absorption which limited the oral bioavailability and therapeutic efficacy of LRD. To improve the oral bioavailability of LRD for allergic disease (urticaria) treatment, LRD solid dispersions (LRD-SDs) were integrating into oro-dispersible films (ODFs). LRD-SDs were prepared through hot-melt extrusion method (HME) using d-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS-1000), and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (SP). Subsequently, LRD-SDs were incorporated in ODFs by solvent casting method. The physicochemical and mechanical properties of LRD solid dispersions-loaded oro-dispersible films (LRD-SDs-ODFs), were evaluated. The in-vitro dissolution, ex-vivo permeation, oral bioavailability, and pharmacodynamics studies were conducted to evaluate LRD-SDs-ODFs efficiency. LRD-SDs-ODFs showed superior solubility and in-vitro dissolution results compared to that of pure LRD (p < 0.05). The solubility of the LRD-SD coded as LTS-4 was 190 times higher than the pure drug in aqueous media. The average hydrodynamic particle size (PS), polydispersity index (PDI), and zeta potential (ZP) of SD particles were 76 ± 2.1 nm, 0.20 ± 0.08 and - 19.16 ± 1.4 mV, respectively. Moreover, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results confirmed the amorphousness of LRD in LRD-SDs-ODFs. The permeability flux of LRD was 44.6 ± 3.1 μg/cm2/h from DPF-5 formulation. Likewise, in vivo oral bioavailability of DPF-5 in Sprague-Dawley rats was significantly increased (p < 0.05) compared to free LRD. Further, wheal area was reduced 20 % higher than LRD in 8 h (p < 0.05). Overall, LRD-SDs-ODFs considerably enhanced LRD solubility, dissolution rate, bioavailability, and antihistaminic efficacy. Our findings show that SDs-ODFs is an effective carrier system for delivering poorly soluble LRD.

Evaluation of the Antimicrobial Activity of Chitosan Nanoparticles against Listeria monocytogenes

Chitosan is obtained from the deacetylation of chitin, and it is known to possess antimicrobial activity. It has attracted attention as it may be used for treating infections caused by different types of microorganisms due to its broad spectrum. Its application in the form of micro- or nanoparticles (CM/CN) has expanded its usage, as in this form, it retains its activity, and remain stable in aqueous solutions. However, inconsistencies in the results reported by different authors have been identified. In this communication, the antimicrobial activity of CN produced from different starting materials was tested against Listeria monocytogenes. It was observed that, even though all the starting materials were reported to have a molecular weight (MW) below 200 kDa and degree of deacetylation (DD) > 75%, the size of the CNs were significantly different (263 nm vs. 607 nm). Furthermore, these differences in sizes exerted a direct effect on the antimicrobial properties of the particles, as when testing the ones with the smallest size, i.e., 263 nm, a lower Minimum Inhibitory Concentration (MIC) was achieved, i.e., 0.04 mg/mL. Even though the largest particles, i.e., 607 nm, in individual experiments were able to achieve an MIC of 0.03 mg/mL, the results with CN presented great variation among replicates and up to 0.2 mg/mL were needed in other replicates. The starting material has a critical impact on the properties of the CN, and it must be carefully characterized and selected for the intended application, and MW and DD solely do not fully account for these properties.

Microbial exopolysaccharides in the biomedical and pharmaceutical industries

The most significant and renewable class of polymeric materials are extracellular exopolysaccharides (EPSs) produced by microorganisms. Because of their diverse chemical and structural makeup, EPSs play a variety of functions in a variety of industries, including the agricultural industry, dairy industry, biofilms, cosmetics, and others, demonstrating their biotechnological significance. EPSs are typically utilized in high-value applications, and current research has focused heavily on them because of their biocompatibility, biodegradability, and compatibility with both people and the environment. Due to their high production costs, only a few microbial EPSs have been commercially successful. The emergence of financial barriers and the growing significance of microbial EPSs in industrial and medical biotechnology has increased interest in exopolysaccharides. Since exopolysaccharides can be altered in a variety of ways, their use is expected to increase across a wide range of industries in the coming years. This review introduces some significant EPSs and their composites while concentrating on their biomedical uses.

Bionanomining of copper-based nanoparticles using pre-processed mine tailings as the precursor

The bacterial synthesis of copper nanoparticles emerges as an eco-friendly alternative to conventional techniques since it comprises a single-step and bottom-up approach, which leads to stable metal nanoparticles. In this paper, we studied the biosynthesis of Cu-based nanoparticles by Rhodococcus erythropolis ATCC4277 using a pre-processed mining tailing as a precursor. The influence of pulp density and stirring rate on particle size was evaluated using a factor-at-time experimental design. The experiments were carried out in a stirred tank bioreactor for 24 h at 25 °C, wherein 5% (v/v) of bacterial inoculum was employed. The O₂ flow rate was maintained at 1.0 L min^-1 and the pH at 7.0. Copper nanoparticles (CuNPs), with an average hydrodynamic diameter of 21 ± 1 nm, were synthesized using 25 g.L^-1 of mining tailing and a stirring rate of 250 rpm. Aiming to visualize some possible biomedical applications of the as-synthesized CuNPs, their antibacterial activity was evaluated against Escherichia coli and their cytotoxicity was evaluated against Murine Embryonic Fibroblast (MEF) cells. The 7-day extract of CuNPs at 0.1 mg mL^-1 resulted in 75% of MEF cell viability. In the direct method, the suspension of CuNPs at 0.1 mg mL^-1 resulted in 70% of MEF cell viability. Moreover, the CuNPs at 0.1 mg mL^-1 inhibited 60% of E. coli growth. Furthermore, the NPs were evaluated regarding their photocatalytic activity by monitoring the oxidation of methylene blue (MB) dye. The CuNPs synthesized showed rapid oxidation of MB dye, with the degradation of approximately 65% of dye content in 4 h. These results show that the biosynthesis of CuNPs by R. erythropolis using pre-processed mine tailing can be a suitable method to obtain CuNPs from environmental and economical perspectives, resulting in NPs useful for biomedical and photocatalytic applications.

A Simple Method for Synthesis of Chitosan Nanoparticles with Ionic Gelation and Homogenization

Chitosan nanoparticles (CNPs) are known to have great utility in many fields (pharmaceutical, agricultural, food industry, wastewater treatment, etc.). In this study we aimed to synthesize sub-100 nm CNPs as a precursor of new biopolymer-based virus surrogates for water applications. We present a simple yet efficient synthesis procedure for obtaining high yield, monodisperse CNPs with size 68-77 nm. The CNPs were synthesized by ionic gelation using low molecular weight chitosan (deacetylation 75-85%) and tripolyphosphate as crosslinker, under rigorous homogenization to decrease size and increase uniformity, and purified by passing through 0.1 μm polyethersulfone syringe filters. The CNPs were characterized using dynamic light scattering, tunable resistive pulse sensing, and scanning electron microscopy. We demonstrate reproducibility of this method at two separate facilities. The effects of pH, ionic strength and three different purification methods on the size and polydispersity of CNP formation were examined. Larger CNPs (95-219) were produced under ionic strength and pH controls, and when purified using ultracentrifugation or size exclusion chromatography. Smaller CNPs (68-77 nm) were formulated using homogenization and filtration, and could readily interact with negatively charge proteins and DNA, making them an ideal precursor for the development of DNA-labelled, protein-coated virus surrogates for environmental water applications.

Preparation of mucoadhesive methacrylated chitosan nanoparticles for delivery of ciprofloxacin

Mucoadhesive polymers and their nanoparticles have attracted a lot of attention in pharmaceutical applications, especially transmucosal drug delivery (TDD). Mucoadhesive polysaccharide-based nanoparticles, particularly chitosan, and its derivatives, are widely used for TDD owing to their outstanding features such as biocompatibility, mucoadhesive, and absorption-enhancing properties. Herein, this study aimed to design potential mucoadhesive nanoparticles for the delivery of ciprofloxacin based on methacrylated chitosan (MeCHI) using the ionic gelation method in the presence of sodium tripolyphosphate (TPP) and compared them with the unmodified chitosan nanoparticles. In this study, different experimental conditions including the polymer to TPP mass ratios, NaCl, and TPP concentration were changed to achieve unmodified and MeCHI nanoparticles with the smallest particle size and lowest polydispersity index. At 4:1 polymer /TPP mass ratio, both chitosan and MeCHI nanoparticles had the smallest size (133 ± 5 nm and 206 ± 9 nm, respectively). MeCHI nanoparticles were generally larger and slightly more polydisperse than the unmodified chitosan nanoparticles. Ciprofloxacin-loaded MeCHI nanoparticles had the highest encapsulation efficiency (69 ± 13 %) at 4:1 MeCHI /TPP mass ratio and 0.5 mg/mL TPP, but similar encapsulation efficiency to that of their chitosan counterpart at 1 mg/mL TPP. They also provided a more sustained and slower drug release compared to their chitosan counterpart. Additionally, the mucoadhesion (retention) study on sheep abomasum mucosa showed that ciprofloxacin-loaded MeCHI nanoparticles with optimized TPP concentration had better retention than the unmodified chitosan counterpart. The percentage of the remained ciprofloxacin-loaded MeCHI and chitosan nanoparticles on the mucosal surface was 96 % and 88 %, respectively. Therefore, MeCHI nanoparticles have an excellent potential for applications in drug delivery.

Current and emerging applications of saccharide-modified chitosan: a critical review

Chitin, as the main component of the exoskeleton of Arthropoda, is a highly available natural polymer that can be processed into various value-added products. Its most important derivative, i.e., chitosan, comprising β-1,4-linked 2-amino-2-deoxy-β-d-glucose (deacetylated d-glucosamine) and N-acetyl-d-glucosamine units, can be prepared via alkaline deacetylation process. Chitosan has been used as a biodegradable, biocompatible, non-antigenic, and nontoxic polymer in some in-vitro applications, but the recently found potentials of chitosan for in-vivo applications based on its biological activities, especially antimicrobial, antioxidant, and anticancer activities, have upgraded the chitosan roles in biomaterials. Chitosan approval, generally recognized as a safe compound by the United States Food and Drug Administration, has attracted much attention toward its possible applications in diverse fields, especially biomedicine and agriculture. Even with some favorable characteristics, the chitosan's structure should be customized for advanced applications, especially due to its drawbacks, such as low drug-load capacity, low solubility, high viscosity, lack of elastic properties, and pH sensitivity. In this context, derivatization with relatively inexpensive and highly available mono- and di-saccharides to soluble branched chitosan has been considered a "game changer". This review critically reviews the emerging technologies based on the synthesis and application of lactose- and galactose-modified chitosan as two important chitosan derivatives. Some characteristics of chitosan derivatives and biological activities have been detailed first to understand the value of these natural polymers. Second, the saccharide modification of chitosan has been discussed briefly. Finally, the applications of lactose- and galactose-modified chitosan have been scrutinized and compared to native chitosan to provide an insight into the current state-of-the research for stimulating new ideas with the potential of filling research gaps.

Formulated chitosan-sodium tripolyphosphate nanoparticles for co-encapsulation of ellagic acid and anti-inflammatory peptide: characterization, stability and anti-inflammatory activity

BACKGROUND

Chitosan (CS) and tripolyphosphate (TPP) can be combined in the development of a material with synergistic properties and promising potential for the conservation of food products. In this study, ellagic acid (EA) and anti-inflammatory peptide (FPL)-loaded CS nanoparticles (FPL/EA NPs) were prepared using the ionic gelation method and optimal preparation conditions were obtained through a single factor design.

RESULTS

The synthesized nanoparticles (NPs) were characterized using a scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Nanoparticles were spherical, with an average size of 308.33 ± 4.61 nm, a polydispersity index (PDI) of 0.254, a zeta potential of +31.7 ± 0.08 mV, and a high encapsulation capacity (22.16 ± 0.79%). An in vitro release study showed that EA/FPL had a sustainable release from FPL/EA NPs. The stability of the FPL/EA NPs was evaluated for 90 days at 0, 25, and 37 °C. Significant anti-inflammatory activity of FPL/EA NPs was verified by nitric oxide (NO) and tumor necrosis factor-α (TNF-α) reduction.

CONCLUSION

These characteristics support the use of CS nanoparticles to encapsulate EA and FPL and improve their bioactivity in food products. © 2023 Society of Chemical Industry.

Optimal heat transport induced by magnetic nanoparticle delivery in vascularised tumours

We describe a novel mathematical model for blood flow, delivery of nanoparticles, and heat transport in vascularised tumour tissue. The model, which is derived via the asymptotic homogenisation technique, provides a link between the macroscale behaviour of the system and its underlying, tortuous micro-structure, as parametrised in Penta and Ambrosi (2015). It consists of a double Darcy's law, coupled with a double advection-diffusion-reaction system describing heat transport, and an advection-diffusion-reaction equation for transport and adhesion of particles. Particles are assumed sufficiently large and do not extravasate to the tumour interstitial space but blood and heat can be exchanged between the two compartments. Numerical simulations of the model are performed using a finite element method to investigate cancer hyperthermia induced by the application of magnetic field applied to injected iron oxide nanoparticles. Since tumour microvasculature is more tortuous than that of healthy tissue and thus suboptimal in terms of fluid and drug transport, we study the influence of the vessels' geometry on tumour temperature. Effective and safe hyperthermia treatment requires tumour temperature within certain target range, generally estimated between 42 °C and 46 °C, for a certain target duration, typically 0.5h to 2h. As temperature is difficult to measure in situ, we use our model to determine the ranges of tortuosity of the microvessels, magnetic intensity, injection time, wall shear stress rate, and concentration of nanoparticles required to achieve given target conditions.

Polyelectrolyte-multivalent molecule complexes: physicochemical properties and applications

The complexation of polyelectrolytes with other oppositely charged structures gives rise to a great variety of functional materials with potential applications in a wide spectrum of technological fields. Depending on the assembly conditions, polyelectrolyte complexes can acquire different macroscopic configurations such as dense precipitates, nanosized colloids and liquid coacervates. In the past 50 years, much progress has been achieved to understand the principles behind the phase separation induced by the interaction of two oppositely charged polyelectrolytes in aqueous solutions, especially for symmetric systems (systems in which both polyions have similar molecular weight and concentration). However, in recent years, the complexation of polyelectrolytes with alternative building blocks such as small charged molecules (multivalent inorganic species, oligopeptides, and oligoamines, among others) has gained attention in different areas. In this review, we discuss the physicochemical characteristics of the complexes formed by polyelectrolytes and multivalent small molecules, putting a special emphasis on their similarities with the well-known polycation-polyanion complexes. In addition, we analyze the potential of these complexes to act as versatile functional platforms in various technological fields, such as biomedicine and advanced materials engineering.

Synthesis of Alginate Nanoparticles Using Hydrolyzed and Enzyme-Digested Alginate Using the Ionic Gelation and Water-in-Oil Emulsion Method

Alginate nanoparticles (AlgNPs) are attracting increasing interest for a range of applications because of their good biocompatibility and their ability to be functionalized. Alginate is an easily accessible biopolymer which is readily gelled by the addition of cations such as calcium, facilitating a cost-effective and efficient production of nanoparticles. In this study, AlgNPs based on acid hydrolyzed and enzyme-digested alginate were synthesized by using ionic gelation and water-in-oil emulsification, with the goal to optimize key parameters to produce small uniform (<200 nm) AlgNPs. By the ionic gelation method, such AlgNPs were obtained when sample concentrations were 0.095 mg/mL for alginate and CaCl₂ in the range of 0.03-0.10 mg/mL. Alginate and CaCl₂ concentrations > 0.10 mg/mL resulted in sizes > 200 nm with relatively high dispersity. Sonication in lieu of magnetic stirring proved to further reduce size and increase homogeneity of the nanoparticles. In the water-in-oil emulsification method, nanoparticle growth was confined to inverse micelles in an oil phase, resulting in lower dispersity. Both the ionic gelation and water-in-oil emulsification methods were suitable for producing small uniform AlgNPs that can be further functionalized as required for various applications.

Comparison of properties and application of starch nanoparticles optimized prepared from different crystalline starches

Starch nanoparticles (SNPs) were produced by nanoprecipitation combined with ultrasonication with the use of different starches (corn, potato and sago starch) and used to stabilize Pickering emulsions. The orthogonal experiment was used to optimize preparation conditions of gelatinization pretreatment duration of 30 min, ultrasonic power of 600 W, and ultrasonic time of 40 min. Compared with native starch, the SNPs were spherical in shape and displayed a V-type crystalline structure with low relative crystallinity and higher degree of double-helix. Compared with native starch-Pickering emulsion, the SNP-Pickering emulsion had a smaller droplet size, more uniform distribution, clearer oil/water interface, and higher static stability of droplets. The sago SNP-Pickering emulsion had the great gelatinous structure and emulsion stability. In addition, the SNP-Pickering emulsion had the better loading efficiency and controlled release performance of curcumin. Meanwhile, the bioavailability of curcumin in sago SNP-Pickering emulsion was highest.

Antiaging properties of antioxidant photoprotective polymeric nanoparticles loaded with coenzyme-Q10

Skin is the most extensive organ within our body. It is continually subjected to stress factors, among which ultraviolet irradiation, a key factor responsible in skin aging since it leads to reactive oxygen species production. In order to fight against these oxidative species, the human body has an innate robust antioxidant mechanism composed of several different substances, one of which is coenzyme Q₁₀. Its capacity to increase cellular energy production and excellent antioxidant properties have been proved, as well as its antiaging properties being able to attenuate cellular damage induced by ultraviolet irradiation in human dermal fibroblasts. However, its high hydrophobicity and photolability hampers its therapeutic potential. In this context, the objective of this work consists of the preparation of chitosan-rosmarinic acid conjugate-based nanoparticles to encapsulate coenzyme Q10 with high encapsulation efficiencies in order to improve its bioavailability and broaden its therapeutic use in skin applications. Hyaluronic acid coating was performed giving stable nanoparticles at physiological pH with 382 ± 3 nm of hydrodynamic diameter (0.04 ± 0.02 polydispersity) and - 18 ± 3 mV of surface charge. Release kinetics studies showed a maximum of 82 % mass release of coenzyme Q₁₀ after 40 min, and radical scavenger activity assay confirmed the antioxidant character of chitosan-rosmarinic acid nanoparticles. Hyaluronic acid-coated chitosan-rosmarinic acid nanoparticles loaded with coenzyme Q₁₀ were biocompatible in human dermal fibroblasts and exhibited interesting photoprotective properties in ultraviolet irradiated cells. In addition, nanoparticles hindered the production of reactive oxygen species, interleukin-6 and metalloproteinase-1, as well as caspase-9 activation maintaining high viability values upon irradiation of dermal fibroblasts. Overall results envision a great potential of these nanovehicles for application in skin disorders or antiaging treatments.

In Situ Release of Ulvan from Crosslinked Ulvan/Chitosan Complex Films and Their Evaluation as Wound Dressings

When a wound forms due to any injuries, it should be covered with a functional wound dressing for accelerating wound healing and reducing infection. In this study, crosslinked ulvan/chitosan complex films were prepared with or without the addition of glycerol and chlorophyll, and their wound healing properties were evaluated for potential application in wound dressing. The results showed that the tensile strength and elongation at break of the prepared ulvan/chitosan complex films were 2.23-2.48 MPa and 83.8-108.5%, respectively. Moreover, their water vapor transmission rates (WVTRs) were in the range of 1791-2029 g/m²-day, providing suitable environment for wound healing. Particularly, these complex films could release ulvan in situ in a short time, and the film with chlorophyll added had the highest release rate, reaching 62.8% after 20 min of releasing. In vitro studies showed that they were biocompatible toward NIH 3T3 and HaCaT cells, and promoted the migration of NIH 3T3 cells. These complex films could protect HaCaT cells from oxidative damage and reduce the production of reactive oxygen species (ROS); the addition of chlorophyll also effectively reduced the inflammatory response induced by LPS as found in the reduction in both NO and IL-6. Animal models showed that the complex films added with glycerol and chlorophyll could promote wound healing in the early stage, while accelerating the regeneration of dermal glands and collagen production. Briefly, these ulvan/chitosan complex films had good physiochemical properties and biological activity, and could accelerate wound healing both in vitro and in vivo.

The Antibacterial Activity of Egyptian Wasp Chitosan-Based Nanoparticles against Important Antibiotic-Resistant Pathogens

The current work discusses the production and characterization of new biodegradable nanoparticles for biomedical applications based on insect chitosan. Chitosan has numerous features due to the presence of primary amine groups in repeating units, such as antibacterial and anticancer activities. When polyanion tripolyphosphate is added to chitosan, it creates nanoparticles with higher antibacterial activity than the original chitosan. In this study, the ionic gelation technique was used to make wasp chitosan nanoparticles (WCSNPs) in which TEM and FTIR were used to investigate the physicochemical properties of the nanoparticles. In addition, the antibacterial activities of chitosan nanoparticles against extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa were evaluated. The extracted wasp chitosan exhibited high solubility in acetic acid and met all standard criteria of all characterization testes for nanoparticles; the zeta potential indicated stable WCSNPs capable of binding to cellular membrane and increasing the cellular uptake. The produced WCSNPs showed growth inhibition activity against all tested strains, and the bacterial count was lower than the initial count. The inhibition percent of WCSNPs showed that the lowest concentration of WCSNPs was found to be effective against tested strains. WCSNPs’ antibacterial activity implies that they could be used as novel, highly effective antibacterial agents in a variety of biological applications requiring antibacterial characteristics.

Chitosan-based scaffolds as drug delivery systems in bone tissue engineering

The bone tissue engineering approach for treating large bone defects becomes necessary when the tissue damage surpasses the threshold of the inherent regenerative ability of the human body. A myriad of natural biodegradable polymers and scaffold fabrication techniques have emerged in the last decade. Chitosan (CS) is especially attractive as a bone scaffold material to support cell attachment and proliferation and mineralization of the bone matrix. The primary amino groups in CS are responsible for properties such as controlled drug release, mucoadhesion, in situ gelation, and transfection. CS-based smart drug delivery scaffolds that respond to environmental stimuli have been reported to have a localized sustained delivery of drugs in the large bone defect area. This review outlines the recent advances in the fabrication of CS-based scaffolds as a pharmaceutical carrier to deliver drugs such as antibiotics, growth factors, nucleic acids, and phenolic compounds for bone tissue regeneration.

Assessment of Chitosan Coating Enriched with Free and Nanoencapsulated Satureja montana L. Essential Oil as a Novel Tool for Beef Preservation

The effect of chitosan coating enriched with free and nanoencapsulated Satureja montana L. essential oil (EO) on microbial, antioxidant and sensory characteristics of beef was analyzed. Different concentrations of free Satureja montana L. EO (SMEO) and nanoparticles (CNPs) were added to chitosan coatings, namely 0.25%, 0.5% and 1%. The beef samples were immersed in the chitosan coatings and stored at +4 °C for 20 days. In this period, the changes in pH value, total viable count (TVC), lactic acid bacteria, psychrophilic bacteria and Pseudomonas spp. were analyzed. The lipid oxidation of beef was determined by the TBAR assay, while sensory analysis was performed by means of the descriptive evaluation method. Generally, the influence of chitosan coating with CNPs on the growth of the tested microorganisms was more pronounced compared to SMEO. Treatment with coating enriched with 1% CNPs resulted in the reduction in TVC and Pseudomonas spp. by 2.4 and 3 log CFU/g, compared to the control, respectively. Additionally, all applied coatings with SMEO and CNPs resulted in the prolonged oxidative stability of the meat The addition of free SMEO created an unnatural aroma for the evaluators, while this odor was neutralized by nanoencapsulation. The durability of color, smell and general acceptability of beef was significantly increased by application of chitosane coatings with the addition of SMEO or SMEO-CNPs, compared to the control. This research indicates the potential application of enriched chitosan coatings in beef preservation in order to improve meat safety and prolong shelf-life.

Development of a Nanoformulation for Oral Protein Administration: Characterization and Preclinical Orofacial Antinociceptive Effect

Nanoencapsulation is a valid alternative for the oral administration of peptide drugs and proteins, as nanoparticles protect them from proteolytic degradation in the gastrointestinal tract and promote the absorption of these macromolecules. The orofacial antinociceptive effect of frutalin (FTL), through the intraperitoneal route, has already been proven. This study aimed to develop, characterize, and evaluate the orofacial antinociceptive activity of an oral formulation containing FTL in acute and neuropathic preclinical tests. Nanoencapsulated FTL was administered by oral route. The acute nociceptive behavior was induced by administering capsaicin to the upper lip and NaCl to the right cornea. The nociceptive behavior was also induced by formalin injected into the temporomandibular joint. The neuropathic pain model involved infraorbital nerve transection (IONX), which induced mechanical hypersensitivity and was assessed by von Frey stimulation. Trpv1 gene expression was analyzed in the trigeminal ganglion. The analyzed sample did not show any cytotoxicity; 52.2% of the FTL was encapsulated, and the size of the nanocapsule was less than 200 nm, the polydispersion was 0.361, and the zeta potential was - 5.87 and - 12.8 mV, with and without FTL, respectively. Nanoencapsulated FTL administered by oral route had an orofacial antinociceptive effect in acute and neuropathic rodent models. The antinociceptive effect of FTL was prevented by ruthenium red, but not by camphor. FTL reduced Trpv1 gene expression. FTL promotes orofacial antinociception, probably due to the antagonism of TRPV1 channels, and the nanoformulation represents an effective method for the oral administration of this protein. HIGHLIGHTS: • Nanoformulation for oral protein administration. • Nanocapsule containing FTL prevents orofacial nociceptive acute and neuropathic pain. • Frutalin promotes orofacial antinociception behavior antagonism of TRPV1 channels.

The maternal-fetal transfer of passive immunity as a mechanism of transplacental nanoparticle drug delivery for prenatal therapies

Nanoparticles administered into the maternal circulation and across the placenta are a potential clinical therapy to treat congenital diseases. The mechanism by which nanoparticles can safely cross the placenta for targeted drug delivery to the fetus remains poorly understood. We demonstrate that the maternal-fetal transfer of passive immunity through the neonatal Fc Receptor (FcRn) can induce the transplacental transfer of chitosan nanoparticles modifed with IgG antibodies (414 ± 27 nm). The transfer of FITC-tagged IgG-modified chitosan nanoparticles was 2.8 times higher (p = 0.0264) compared to similarly-sized unmodified chitosan nanoparticles (375 ± 17 nm). Co-administration of free IgG competitively diminished the transplacental transfer of IgG-modified nanoparticles, yet unmodified nanoparticles remained unaffected. Colocalization of the FcRn and the IgG-modified chitosan nanoparticles were observed with confocal microscopy. Barrier function before and after nanoparticle administration remained intact as determined by TEER (75-79 Ω cm²) and immmunofluorescence of ZO-1 tight junction proteins. The results provide insight into the clinical applications of nanoparticles for prenatal therapies using the mechanism of the maternal-fetal transfer of passive immunity.

Design and Development of Levodopa Loaded Polymeric Nanoparticles for Intranasal Delivery

Intranasal delivery is an alternative administration route to deliver levodopa (L-Dopa) to the brain. This drug delivery route offers high drug permeability across the nasal epithelium and rapid absorption into the central nervous system (CNS) while bypassing first-pass metabolism. In this study, we developed a library of polymeric nanocarrier systems for L-Dopa utilising poly(lactic-co-glycolic acid) (PLGA) and chitosan. A total of three PLGA nanoparticles formulations (P1, P2 and P3) were prepared using a modified water-in-oil-in-water (W/O/W) solvent evaporation technique, while four formulations of chitosan nanoparticles (C1, C2, C3 and C4) were prepared by ionic gelation method with sodium tripolyphosphate (TPP) as a cross-linking agent. Upon characterising nanocarriers developed, it was discovered that C2 demonstrated the best results with regard to droplet size (553 ± 52 nm), polydispersity index (0.522), zeta potential (+46.2 ± 2.3 mV), and encapsulation efficiency (82.38% ± 1.63). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) further corroborated the particle size analysis highlighting that C2 displayed uniform particle size with spherical morphology. Additionally, X-ray diffraction analysis (XRD) revealed that C2 was in an amorphous state while Fourier transform infrared (FTIR) analysis showed that there were no chemical interactions that might change the chemical structure of L-Dopa within the polymeric nanoparticle matrix. Lastly, an in-vivo intranasal study in male Wistar rats showed that the absorption of L-Dopa when formulated as chitosan nanoparticles was significantly enhanced (p < 0.05) by approximately two-fold compared to unmodified L-Dopa. Therefore, this work illustrates that formulating L-Dopa into chitosan nanoparticles for intranasal delivery is a potentially viable formulation strategy to improve the bioavailability of the drug for the treatment of Parkinson’s disease.

Fabrication and characterization of chitosan nanoparticles using the coffee-ring effect for photodynamic therapy

BACKGROUND AND OBJECTIVES

Biocompatible nanoparticles have been increasingly used in a variety of medical applications, including photodynamic therapy. Although the impact of synthesis parameters and purification methods is reported in previous studies, it is still challenging to produce a reliable protocol for the fabrication, purification, and characterization of nanoparticles in the 200-300 nm range that are highly monodisperse for biomedical applications.

STUDY DESIGN/MATERIALS AND METHODS

We investigated the synthesis of chitosan nanoparticles in the 200-300 nm range by evaluating the chitosan to sodium tripolyphosphate (TPP) mass ratio and acetic acid concentration of the chitosan solution. Chitosan nanoparticles were also crosslinked to rose bengal and incubated with human breast cancer cells (MCF-7) to test photodynamic activity using a green laser (λ = 532 nm, power = 90 mW).

RESULTS

We established a simple protocol to fabricate and purify biocompatible nanoparticles with the most frequent size occurring between 200 and 300 nm. This was achieved using a chitosan to TPP mass ratio of 5:1 in 1% v/v acetic acid at a pH of 5.5. The protocol involved the formation of nanoparticle coffee rings that showed the particle shape to be spherical in the first approximation. Photodynamic treatment with rose bengal-nanoparticles killed ~98% of cancer cells.

CONCLUSION

A simple protocol was established to prepare and purify spherical and biocompatible chitosan nanoparticles with a peak size of ~200 nm. These have remarkable antitumor activity when coupled with photodynamic treatment.

Inactivation of Polymicrobial Biofilms of Foodborne Pathogens Using Epsilon Poly-L-Lysin Conjugated Chitosan Nanoparticles

A mixed culture (polymicrobial) biofilm provides a favorable environment for pathogens to persist in the food processing environment and to contaminate food products. Inactivation and eradication of such biofilms from food processing environments are achieved by using harsh disinfectants, but their toxicity and environmentally hostile characteristics are unsustainable. This study aims to use food-grade natural nanoparticulated antimicrobials to control mixed-culture biofilms. Chitosan, a natural broad-spectrum antimicrobial biopolymer (polysaccharide) from crustaceans, was derivatized to produce chitosan nanoparticles (ChNP) as a carrier for another broad-spectrum antimicrobial agent, ε-poly-L-lysine (PL), to synthesize ChNP-PL conjugate. The antimicrobial activity of ChNP and ChNP-PL was tested against mixed-culture biofilms. ChNP-PL (~100 nm) exhibited a synergistic antimicrobial and anti-biofilm effect against mono or mixed-culture biofilms of five foodborne pathogens, including Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica serovar Enteritidis, Escherichia coli O157:H7, and Pseudomonas aeruginosa. ChNP-PL treatment prevented biofilm formation by mono or mixed cultures of L. monocytogenes, P. aeruginosa, and E. coli O157:H7, and bacterial counts were either below the detection limit or caused 3.5–5 log reduction. ChNP-PL also inactivated preformed biofilms. In monoculture biofilm, ChNP-PL treatment reduced L. monocytogenes counts by 4.5 logs, S. Enteritidis by 2 logs, E. coli by 2 logs, and S. aureus by 0.5 logs, while ChNP-PL had no inhibitory effect on P. aeruginosa. In vitro mammalian cell-based cytotoxicity analysis confirmed ChNP-PL to have no deleterious effect on intestinal HCT-8 cell line. In conclusion, our results show ChNP-PL has strong potential to prevent the formation or inactivation of preformed polymicrobial biofilms of foodborne pathogens.

Nanoencapsulation of hydroxytyrosol in chitosan crosslinked with sodium bisulfate tandem ultrasonication: Techno-characterization, release and antiproliferative properties

This research includes production of chitosan nanocapsules through ionic gelation with sodium bisulfate for nanoencapsulation of hydroxytyrosol (HT) using ultrasonication in tandem. The resulting nanocapsules encapsulating HT were analyzed for particle size, ζ-potential, packaging characteristics, FESEM, ATR-FTIR, XRD, DSC, in vitro release, antioxidant potential and antiproliferative properties. The nanocapsules (size 119.50-365.21 nm) were spherical to irregular shaped with positive ζ-potential (17.50-18.09 mV). The encapsulation efficiency of 5 mg/g HT (HTS1) and 20 mg/g HT (HTS2) was 77.13% and 56.30%, respectively. The nanocapsules were amorphous in nature with 12.34% to 15.48% crystallinity and crystallite size between 20 nm and 27 nm. Formation of nanocapsules resulted in increasing the glass transition temperature. HTS2 delivered 67.12% HT (HTS1 58.89%) at the end of the simulated gastrointestinal digestion. The nanoencapsulated HT showed higher antioxidant and antiproliferative (against A549 and MDA-MB-231 cancer cell lines) properties than the free HT.

Nanotechnology for Topical Drug Delivery to the Anterior Segment of the Eye

Topical drug delivery is one of the most challenging aspects of eye therapy. Eye drops are the most prevalent drug form, especially for widely distributed anterior segment eye diseases (cataracts, glaucoma, dry eye syndrome, inflammatory diseases, etc.), because they are convenient and easy to apply by patients. However, conventional drug formulations are usually characterized by short retention time in the tear film, insufficient contact with epithelium, fast elimination, and difficulties in overcoming ocular tissue barriers. Not more than 5% of the total drug dose administered in eye drops reaches the interior ocular tissues. To overcome the ocular drug delivery barriers and improve drug bioavailability, various conventional and novel drug delivery systems have been developed. Among these, nanosize carriers are the most attractive. The review is focused on the different drug carriers, such as synthetic and natural polymers, as well as inorganic carriers, with special attention to nanoparticles and nanomicelles. Studies in vitro and in vivo have demonstrated that new formulations could help to improve the bioavailability of the drugs, provide sustained drug release, enhance and prolong their therapeutic action. Promising results were obtained with drug-loaded nanoparticles included in in situ gel.

Bombesin Peptide Conjugated Water-Soluble Chitosan Gallate-A New Nanopharmaceutical Architecture for the Rapid One-Pot Synthesis of Prostate Tumor Targeted Gold Nanoparticles

PURPOSE

We report herein bombesin peptide conjugated water-soluble chitosan gallate as a template for rapid one-pot synthesis of gold nanoparticles (AuNPs) with capabilities to target receptors on prostate cancer cells.

METHODS

Water-soluble chitosan (WCS), anchored with gallic acid (GA) and LyslLys3 (1,4,7,10-tetraazacyclo dodecane-1,4,7,10-tetraacetic acid) bombesin 1-14 (DBBN) peptide, provides a tumor targeting nanomedicine agent. WCS nanoplatforms provide attractive strategies with built-in capabilities to reduce gold (III) to gold nanoparticles with stabilizing and tumor-targeting capabilities. WCS-GA-DBBN encapsulation around gold nanoparticles affords optimum in vitro stability.

RESULTS

The DBBN content in the WCS-GA-DBBN sample was ~27%w/w. The antioxidant activities of WCS-GA and WCS-GA-DBBN nanocolloids were enhanced by 12 times as compared to the nascent WCS. AuNPs with a desirable hydrodynamic diameter range of 40-60 nm have been efficiently synthesized using WCS-GA and WCS-GA-DBBN platforms. The AuNPs were stable over 4 days after preparation and ~3 days after subjecting to all relevant biological fluids. The AuNPs capped with WCS-GA-DBBN peptide exhibited superior cellular internalization into prostate tumor (PC-3) cells with evidence of receptor mediated endocytosis.

CONCLUSION

The AuNPs capped with WCS-GA-DBBN exhibited selective affinity toward prostate cancer cells. AuNPs conjugated with WCS-GA-DBBN serve as a new generation of theranostic agents for treating various neoplastic diseases, thus opening-up new applications in oncology.

Recent progress on Pickering emulsions stabilized by polysaccharides-based micro/nanoparticles

Pickering emulsions stabilized by micro/nanoparticles have attracted considerable attention owing to their great potential in various applications ranging from cosmetic and food industries to catalysis, tissue engineering and drug delivery. There is a growing demand to design "green" micro/nanoparticles for constructing stable Pickering emulsions. Micro/nanoparticles derived from the naturally occurring polysaccharides including cellulose, chitin, chitosan and starch are capable of assembling at oil/water interfaces and are promising green candidates because of their excellent biodegradability and renewability. The physicochemical properties of the micro/nanoparticles, which are determined by the fabricating approaches and/or post-modification methods, have a significant effect on the characteristics of the final Pickering emulsions and their applications. Herein, recent advances on Pickering emulsions stabilized by polysaccharides-based micro/nanoparticles and the construction of functional materials including porous foams, microcapsules and latex particles from these emulsions as templates, are reviewed. In particular, the effects of micro/nanoparticles properties on the characteristics of the Pickering emulsions and their applications are discussed. Furthermore, the obstacles that hinder the practical applications of polysaccharides-based micro/nanoparticles and Pickering emulsions as well as the prospects for the future development, are discussed.

Production and characterization of graphene from carbonaceous rice straw by cost-effect extraction

This paper describes the synthesis of graphene-based activated carbon from carbonaceous rice straw fly ash in an electrical furnace and the subsequent potassium hydroxide extraction. The produced graphene has a proper morphological structure; flakes and a rough surface can be observed. The average size of the graphene was defined as up to 2000 nm and clarification was provided by high-resolution microscopes (FESEM and FETEM). Crystallinity was confirmed by surface area electron diffraction. The chemical bonding from the graphene was clearly observed, with -C=C- and O-H stretching at peaks of 1644 cm^-1 and 3435 cm^-1, respectively. Impurities in the graphene were found using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The measured size, according to zeta-potential analysis, was 8722.2 ± 25 nm, and the average polydispersity index was 0.576. The stability of the mass reduction was analyzed by a thermogravimetric at 100 °C, with a final reduction of ~ 11%.