Preparation and characterization of antioxidant nanoparticles composed of chitosan and fucoidan for antibiotics delivery

Fucoidan/chitosan hydrogels as carrier for sustained delivery of platelet-rich fibrin containing bioactive molecules

Platelet-rich fibrin (PRF), derived from human blood, rich in wound healing components, has drawbacks in direct injections, such as rapid matrix degradation and growth factor release. Marine polysaccharides, mimicking the human extracellular matrix, show promising potential in tissue engineering. In this study, we impregnated the self-assembled fucoidan/chitosan (FU_CS) hydrogels with PRF obtaining PRF/FU_CS hydrogels. Our objective was to analyze the properties of a hydrogel and the sustained release of growth factors from the hydrogel that incorporates PRF. The results of SEM and BET-BJH demonstrated the relatively porous nature of the FU_CS hydrogels. ELISA data showed that combining FU_CS hydrogel with PRF led to a gradual 7-day sustained release of growth factors (VEGF, EGF, IL-8, PDGF-BB, TGF-β1), compared to pure PRF. Histology confirmed ELISA data, demonstrating uniform PRF fibrin network distribution within the FU_CS hydrogel matrix. Furthermore, the FU_CS hydrogels revealed excellent cell viability. The results revealed that the PRF/FU_CS hydrogel has the potential to promote wound healing and tissue regeneration. This would be the first step in the search for improved growth factor release.

Fucoidan-mediated targeted delivery of dasatinib-loaded nanoparticles amplifies apoptosis and endows cytotoxic potential in triple-negative breast cancer

Dasatinib (DST) is a tyrosine kinase inhibitor with established antiproliferative activity in Triple-negative breast cancer. Conventional treatment strategies with DST have several pitfalls related to the development of resistance, lower cellular uptake and unwanted adverse effects. To address these issues, we have prepared P-selectin-targeted nanoparticles of DST with fucoidan (FUC) as a ligand. Poly lactide-co-glycolide nanoparticles of DST were coated with chitosan (CH) and FUC via electrostatic interaction (DST-CH-FUC-NPs). The mean particle size of 210.36 ± 0.66 nm and a polydispersity index of 0.234 ± 0.013 was observed for DST-CH-FUC-NPs. TEM and FTIR analysis proved CH coating followed by an FUC layer on nanoparticles. DST-CH-FUC-NPs showed a sustained release profile up to 120 h and 2.9 times less hemolytic potential than free DST suspension. DST-CH-FUC-NPs demonstrated 8-fold higher cytotoxicity compared to free DST in MDA-MB-231 cells. Rhodamine-CH-FUC- NPs showed 19 times and 3 times higher cellular uptake than free Rhodamine and Rhodamine-CH-NPs, respectively. DST-CH-FUC-NPs also displayed increased ROS production and mitochondrial membrane potential damage. Apoptosis study revealed a 7.5-fold higher apoptosis index for DST-CH-FUC-NPs than free DST. Subsequently, the DST-CH-FUC-NPs showed increased inhibition of cell migration, where approximately 5 % wound closure was noted. Further, DST-CH-FUC-NPs confirmed higher disruption of lysosomal membrane integrity, which is well correlated with apoptosis results. In addition, developed NPs were nontoxic on MCF 10 A normal cells. All these findings suggest that fabricated DST-CH-FUC-NPs are promising biocompatible carriers for tumor-targeted delivery and enhanced efficacy of dasatinib.

Fucoidan-proanthocyanidins nanoparticles protect against cisplatin-induced acute kidney injury by activating mitophagy and inhibiting mtDNA-cGAS/STING signaling pathway

Fucoidan (FU) is a natural polymer from marine organisms, which has been widely studied and applied in drug delivery. In this study, FU nanoparticles loaded with proanthocyanidins (PCs) (FU/PCs NPs) were prepared and their effect and mechanism in protecting cisplatin-induced acute kidney injury (AKI) were studied. The in vitro studies confirmed that FU/PCs NPs increased the antioxidant activity of free PCs and protected the death of human kidney proximal tubule (HK-2) cells induced by cisplatin. Further mechanism studies showed that FU/PCs NPs protected the mitochondrial damage induced by cisplatin, activated mitophagy, inhibited the release of mitochondrial DNA (mtDNA), and inhibited the cGAS/STING signal pathway. The in vivo results also indicated that FU/PCs NPs protected cisplatin-induced AKI, including inhibiting the increase of blood urea nitrogen (BUN) and serum creatinine (SCr) levels induced by cisplatin. The mechanism studies confirmed that cisplatin induced an increase in the expression of mitophagy-related protein Pink/Pakrin, mitochondrial mtDNA release and cGAS/STING expression in mice kidney tissues. Pre-administration of FU/PCs NPs further activated mitophagy, as well as inhibiting mtDNA release and cGAS/STING expression. In conclusion, our research proved the role of mitophagy-mtDNA-cGAS/STING signal was involved in cisplatin-induced AKI.

Pectins from the sea grass Enhalus acoroides (L.f.) Royle: Structure, biological activity and ability to form nanoparticles

Two pectins from the seagrass Enhalus acoroides (L.f.) Royle were isolated for the first time. Their structures and biological activities were investigated. NMR spectroscopy showed one of them to consist exclusively from the repeating →4-α-d-GalpUA→ residue (Ea1), while the other had a much more complex structure that also included 1→3-linked α-d-GalpUA residues, 1→4-linked β-apiose residues and small amounts of galactose and rhamnose (Ea2). The pectin Ea1 showed noticeable dose-dependent immunostimulatory activity, the Ea2 fraction was less effective. Both pectins were used to create pectin-chitosan nanoparticles for the first time, and the influence of pectin/chitosan mass ratio on their size and zeta potential was investigated. Ea1 particles were slightly smaller than Ea2 particles (77 ± 16 nm vs 101 ± 12 nm) and less negatively charged (-23 mV vs -39 mV). Assessment of their thermodynamic parameters showed that only the second pectin could form nanoparticles at room temperature.

Development and characterization of a fucoidan-based nanoemulsion using Nigella sativa oil for improvement of anti-obesity activity of fucoxanthin in an obese rat model

The anti-obesity activity of encapsulated fucoxanthin in fucoidan-based nanoemulsion was investigated. Then, high-fat diet (HFD) induced-obese rats were fed along with different treatments including administration of encapsulated fucoxanthin (10 mg/kg and 50 mg/kg/day), fucoidan (70 mg/kg), Nigella sativa oil (250 mg/kg), metformin (200 mg/kg), and free form of fucoxanthin (50 mg/kg) by oral gavage daily for 7 weeks. The study discovered that fucoidan-based nanoemulsions with a low and high dose of fucoxanthin had droplet size in the range of 181.70-184.87 nm and encapsulation efficacy of 89.94-91.68 %, respectively. Also exhibited 75.86 % and 83.76 % fucoxanthin in vitro release. The TEM images and FTIR spectera confirmed the particle size and encapsulation of fucoxanthin, respectively. Moreover, in vivo results revealed that encapsulated fucoxanthin reduced body and liver weight compared with a HFD group (p < 0.05). Biochemical parameters (FBS, TG, TC, HDL, LDL) and liver enzymes (ALP, AST, and ALT) were decreased after fucoxanthin and fucoidan administration. According to the histopathological analysis, fucoxanthin and fucoidan attenuated lipid accumulation in the liver.

DEAE/Catechol-Chitosan Conjugates as Bioactive Polymers: Synthesis, Characterization, and Potential Applications

This work provides the first description of the synthesis and characterization of water-soluble chitosan (Cs) derivatives based on the conjugation of both diethylaminoethyl (DEAE) and catechol groups onto the Cs backbone (Cs-DC) in order to obtain a Cs derivative with antioxidant and antimicrobial properties. The degree of substitution [DS (%)] was 35.46% for DEAE and 2.53% for catechol, determined by spectroscopy. Changes in the molecular packing due to the incorporation of both pendant groups were described by X-ray diffraction and thermogravimetric analysis. For Cs, the crystallinity index was 59.46% and the maximum decomposition rate appeared at 309.3 °C, while for Cs-DC, the values corresponded to 16.98% and 236.4 °C, respectively. The incorporation of DEAE and catechol groups also increases the solubility of the polymer at pH > 7 without harming the antimicrobial activity displayed by the unmodified polymer. The catecholic derivatives increase the radical scavenging activity in terms of the half-maximum effective concentration (EC₅₀). An EC₅₀ of 1.20 μg/mL was found for neat hydrocaffeic acid (HCA) solution, while for chitosan-catechol (Cs-Ca) and Cs-DC solutions, concentrations equivalent to free HCA of 0.33 and 0.41 μg/mL were required, respectively. Cell culture results show that all Cs derivatives have low cytotoxicity, and Cs-DC showed the ability to reduce the activity of reactive oxygen species by 40% at concentrations as low as 4 μg/mL. Polymeric nanoparticles of Cs derivatives with a hydrodynamic diameter (D_h) of around 200 nm, unimodal size distributions, and a negative ζ-potential were obtained by ionotropic gelation and coated with hyaluronic acid in aqueous suspension, providing the multifunctional nanoparticles with higher stability and a narrower size distribution.

Fucoidan from Fucus vesiculosus: Evaluation of the Impact of the Sulphate Content on Nanoparticle Production and Cell Toxicity

The composition of seaweeds is complex, with vitamins, phenolic compounds, minerals, and polysaccharides being some of the factions comprising their structure. The main polysaccharide in brown seaweeds is fucoidan, and several biological activities have been associated with its structure. Chitosan is another marine biopolymer that is very popular in the biomedical field, owing to its suitable features for formulating drug delivery systems and, particularly, particulate systems. In this work, the ability of fucoidan to produce nanoparticles was evaluated, testing different amounts of a polymer and using chitosan as a counterion. Nanoparticles of 200-300 nm were obtained when fucoidan prevailed in the formulation, which also resulted in negatively charged nanoparticles. Adjusting the pH of the reaction media to 4 did not affect the physicochemical characteristics of the nanoparticles. The IC50 of fucoidan was determined, in both HCT-116 and A549 cells, to be around 160 µg/mL, whereas it raised to 675-100 µg/mL when nanoparticles (fucoidan/chitosan = 2/1, w/w) were tested. These marine materials (fucoidan and chitosan) provided features suitable to formulate polymeric nanoparticles to use in biomedical applications.

Nano-Sized Fucoidan Interpolyelectrolyte Complexes: Recent Advances in Design and Prospects for Biomedical Applications

The marine polysaccharide fucoidan (FUC) is a promising polymer for pharmaceutical research and development of novel drug delivery systems with modified release and targeted delivery. The presence of a sulfate group in the polysaccharide makes FUC an excellent candidate for the formation of interpolyelectrolyte complexes (PECs) with various polycations. However, due to the structural diversity of FUC, the design of FUC-based nanoformulations is challenging. This review describes the main strategies for the use of FUC-based PECs to develop drug delivery systems with improved biopharmaceutical properties, including nanocarriers in the form of FUC-chitosan PECs for pH-sensitive oral delivery, targeted delivery systems, and polymeric nanoparticles for improved hydrophobic drug delivery (e.g., FUC-zein PECs, core-shell structures obtained by the layer-by-layer self-assembly method, and self-assembled hydrophobically modified FUC particles). The importance of a complex study of the FUC structure, and the formation process of PECs based on it for obtaining reproducible polymeric nanoformulations with the desired properties, is also discussed.

Self-assembled polyelectrolyte complexes of chitosan and fucoidan for sustained growth factor release from PRP enhance proliferation and collagen deposition in diabetic mice

Diabetic wound management is a serious health care challenge due to higher rates of relapse, expensive treatment approaches, and poor healing outcomes. Among cell-based therapies, use of platelet-rich plasma (PRP) has been shown to be effective for diabetic wounds, but its poor shelf-life limits its clinical use. Here, we demonstrate a simple but effective polymer system to increase the shelf-life of PRP by developing a polyelectrolyte complex with dropwise addition of chitosan solution containing PRP by simple mixing at room temperature. Thus, prepared chitosan-fucoidan (CF) carrier complex encapsulated more than 95% of the loaded PRP. The resulting CF/PRP colloids were spherical in shape and ensured extended PRP release up to 72 h at 37 °C. Routine characterization (FT-IR, XRD, SEM) showed the material properties. The biological assays showed that CF complexes were biocompatible while CF/PRP enhanced the proliferation of fibroblasts and keratinocytes via higher Ki67 expression and fibroblast migration. Further investigations using a diabetic mouse model demonstrated significantly higher wound contraction and histopathological observations showed increased fibroblast migration, and collagen and cytokeratin deposition in treatment groups. The results are suggestive of the efficacy of CF/PRP as a cost-effective topical formulation for the sustained delivery of growth factors in treating chronic diabetic wounds.

Synchrotron-based infrared microspectroscopy of polymeric nanoparticles and skin: Unveiling molecular interactions to enhance permeation

The application of nanoparticles as permeation enhancers in skin drug delivery is a growing research field. However, the mechanisms of nanoparticles' interaction with the skin structure are still unknown. Fucoidan/chitosan nanoparticles have demonstrated several physicochemical and biological advantages, among which is the enhancement of skin permeation. This study aims to elucidate permeation enhancement mechanisms using synchrotron-based Fourier Transform Infrared Microspectroscopy (SR-FTIRM) combined with multivariate analysis and in vitro skin permeation assay. Given the molecular weight influence on chitosan's properties, the nanoparticles-skin interactions were evaluated with nanoparticles produced using low- and medium-molecular-weight chitosan. Chemical maps and spectral analysis revealed that fucoidan/chitosan nanoparticles induced changes in the lipids and protein regions. Inter-sample spectral differences were identified using principal component analysis. Low molecular weight fucoidan/ chitosan nanoparticles caused changes in the skin lipids' lateral packing and structure at the stratum corneum layer towards a less ordered state and higher fluidity, and no evidence was found on proteins structure. The opposite was revealed for medium molecular weight fucoidan/chitosan nanoparticles, which induced changes in the secondary structure of keratin and altered lipid structure to an ordered and dense conformation. In vitro permeation assays with Franz diffusion cells correlate with the observed changes in the skin lipid and protein structure with enhanced skin permeation of a hydrophilic molecule incorporated within the fucoidan/chitosan nanoparticles. The findings of this study unveil molecular changes in the skin structure induced by the nanoparticles only possible with the application of the powerful and precise SR-FTIRM technique. This knowledge allows the design of nanoparticles towards an internalization pathway determining their fate within the skin structure.

Preparation of Fucoxanthin Nanoemulsion Stabilized by Natural Emulsifiers: Fucoidan, Sodium Caseinate, and Gum Arabic

This study was proposed to investigate the possibility of O/W nanoemulsion stabilization via natural emulsifiers as a delivery system for fucoxanthin. Nanoemulsions were prepared using ultrasonic treatment (150 W, amplitude 80%, 10 min) with different levels (0.5%, 1%, and 2% wt) of fucoidan, gum Arabic, and sodium caseinate as natural emulsifires and they were compared with tween 80. Then, the creaming index, stability, encapsulation efficacy, Fourier-transform infrared (FT-IR) spectroscopy, and in vitro release were evaluated. The best stability and lowest creaming index were observed at 2% wt of emulsifiers. Nanoemulsions with droplet sizes (113.27−127.50 nm) and zeta potentials (−32.27 to −58.87 mV) were prepared. The droplet size of nanoemulsions was reduced by increasing the emulsifier concentration, and the best nanoemulsion stability after 15 days of storage was in the following order: tween 80 > sodium caseinate > fucoidan > gum Arabic. The encapsulation efficacy of nanoemulsions stabilized by sodium caseinate, fucoidan, and gum Arabic were 88.51 ± 0.11%, 79.32 ± 0.09%, and 60.34 ± 0.13%, respectively. The in vitro gastrointestinal fucoxanthin release of nanoemulsion stabilized with tween 80, sodium caseinate, fucoidan, and gum Arabic were 85.14 ± 0.16%, 76.91 ± 0.34%, 71.41 ± 0.14%, and 68.98 ± 0.36%, respectively. The release of fucoxanthin from nanoemulsions followed Fickian diffusion. The FTIR also confirmed the encapsulation of fucoxanthin.

Synthesis and Characterization of Fucoidan-Chitosan Nanoparticles Targeting P-Selectin for Effective Atherosclerosis Therapy

Atherosclerosis is the key pathogenesis of cardiovascular diseases; oxidative stress, which is induced by the generated excess reactive oxygen species (ROS), has been a crucial mechanism underlying this pathology. Nanoparticles (NPs) represent a novel strategy for the development of potential therapies against atherosclerosis, and multifunctional NPs possessing antioxidative capacities hold promise for amelioration of vascular injury caused by ROS and for evading off-target effects; materials that are currently used for NP synthesis often serve as vehicles that do not possess intrinsic biological activities; however, they may affect the surrounding healthy environment due to decomposition of products. Herein, we used nontoxic fucoidan, a sulfated polysaccharide derived from a marine organism, to develop chitosan–fucoidan nanoparticles (CFNs). Then, by binding to P-selectin, an inflammatory adhesion exhibited molecule expression on the endothelial cells and activated platelets, blocking leukocyte recruitment and rolling on platelets and endothelium. CFNs exhibit antioxidant and anti-inflammatory properties. Nevertheless, by now, the application of CFNs for the target delivery regarding therapeutics specific to atherosclerotic plaques is not well investigated. The produced CFNs were physicochemically characterized using transmission electron microscopy (TEM), together with Fourier transform infrared spectroscopy (FTIR). Evaluations of the in vitro antioxidant as well as anti-inflammatory activities exhibited by CFNs were based on the measurement of their ROS scavenging abilities and investigating inflammatory mediator levels. The in vivo pharmacokinetics and binding efficiency of the CFNs to atherosclerotic plaques were also evaluated. The therapeutic effects indicated that CFNs effectively suppressed local oxidative stress and inflammation by targeting P-selectin in atheromatous plaques and thereby preventing the progression of atherosclerosis.

Fucoidan-based nanoparticles: Preparations and applications

Nanoparticle-based therapy has gained much attention in the pharmaceutical industry. Fucoidan is a sulfated polysaccharide naturally derived from marine brown algae and is widely used for medical applications. We explore preparation of fucoidan-based nanoparticles and their biomedical applications in the current review. The fucoidan-based nanoparticles have been synthesized using microwave, emulsion, solvent evaporation, green synthesis, polyelectrolyte self-assembly, precipitation, and ultrasonication methods. The synthesized nanoparticles have particle sizes ranging from 100 to 400 nm. Therefore, fucoidan-based nanoparticles have a variety of potential therapeutic applications, including drug delivery, cancer therapies, tissue engineering, antimicrobial applications, magnetic resonance imaging contrast, and atherothrombosis imaging. For example, fucoidan nanoparticles have been used to deliver curcumin, dextran, gentamicin, epigallocatechin gallate, and cisplatin for cancer therapies. Furthermore, fucoidan nanoparticles coupled with metal nanoparticles have been used to target and recognize clinical conditions for diagnostic purposes. Hence, fucoidan-based nanoparticles have been helpful for biomedical applications.

Oppositely Charged Pickering Emulsion Co-Stabilized by Chitin Nanoparticles and Fucoidan: Influence of Environmental Stresses on Stability and Antioxidant Activity

Single emulsifiers exhibit varying degrees of restriction in stabilizing emulsions. Oppositely charged chitin nanoparticles and fucoidan complex particles were used as emulsifiers to stabilize a o/w Pickering emulsion and explore its stability and antioxidant activity under different environmental stresses. The results showed that the emulsion with the smallest mean particle size (1.02 μm) and strongest zeta potential (−29.3 mV) was formed at pH 7. Moreover, at this pH, it presented the highest physical stability and antioxidant activity and the lowest emulsion creaming index. The investigation of the effect of temperature on the stability and antioxidant activity of the emulsion revealed that, after freezing/thawing at −20 °C, the emulsion was unstable, the particle size increased, and the stability and antioxidant activity were low. In contrast, the emulsions treated at 25, 37, and 60 °C displayed no significant differences and exhibited high stabilities and antioxidant activities. Additionally, increasing the salt ion concentration further decreased the emulsion stability and antioxidant activity. Particularly, the emulsion with a salt concentration of 500 mM displayed the lowest stability, and stratification occurred after 30 d of storage. The Pickering emulsion remained stable under different environmental stresses expect for at a temperature of −20 °C and 500 mM salt ion concentration.

Injectable Thermosensitive Chitosan-Collagen Hydrogel as A Delivery System for Marine Polysaccharide Fucoidan

Fucoidans, sulfated polysaccharides from brown algae, possess multiple bioactivities in regard to osteogenesis, angiogenesis, and inflammation, all representing key molecular processes for successful bone regeneration. To utilize fucoidans in regenerative medicine, a delivery system is needed which temporarily immobilizes the polysaccharide at the injured site. Hydrogels have become increasingly interesting biomaterials for the support of bone regeneration. Their structural resemblance with the extracellular matrix, their flexible shape, and capacity to deliver bioactive compounds or stem cells into the affected tissue make them promising materials for the support of healing processes. Especially injectable hydrogels stand out due to their minimal invasive application. In the current study, we developed an injectable thermosensitive hydrogel for the delivery of fucoidan based on chitosan, collagen, and β-glycerophosphate (β-GP). Physicochemical parameters such as gelation time, gelation temperature, swelling capacity, pH, and internal microstructure were studied. Further, human bone-derived mesenchymal stem cells (MSC) and human outgrowth endothelial cells (OEC) were cultured on top (2D) or inside the hydrogels (3D) to assess the biocompatibility. We found that the sol-gel transition occurred after approximately 1 min at 37 °C. Fucoidan integration into the hydrogel had no or only a minor impact on the mentioned physicochemical parameters compared to hydrogels which did not contain fucoidan. Release assays showed that 60% and 80% of the fucoidan was released from the hydrogel after two and six days, respectively. The hydrogel was biocompatible with MSC and OEC with a limitation for OEC encapsulation. This study demonstrates the potential of thermosensitive chitosan-collagen hydrogels as a delivery system for fucoidan and MSC for the use in regenerative medicine.

Nanotechnology‐enhanced edible coating application on climacteric fruits

Climacteric fruits continue to ripen after harvest and produce ethylene, coupled with an increase in respiration rate, which contributes to more rapid perishability. Inhibition of ethylene biosynthesis has been shown to be an efficient way to delay the onset of ripening and lengthen shelf life. The use of edible materials as coatings presents an efficient approach in preserving the quality of fruits. Edible coatings have many benefits, such as affordability, ease of application, and use of natural ingredients. Nanotechnology provides interesting approaches to the management of fruit shelf life after harvest. Nanotechnology has the capacity of producing new materials by minimizing the size of components to a nanometric level. These kinds of nanomaterials possess distinct and improved properties for delaying fruit ripening and decay. The main goal of adding nanoparticles to edible coatings is to enhance the biopolymer's mechanical and water vapor barrier properties. Nanoparticles also contain biopolymer‐like features and are thought to have superior antibacterial, antifungal, and antiviral properties than edible coatings. This review is aimed at summarizing recent findings on the application of edible coatings in the form of nanoparticles, and their effect on quality parameters and shelf life extension of climacteric fruits. Peer‐reviewed articles were obtained by using Scopus and science direct. The current materials widely used for coating climacteric fruits are zinc, silver and chitosan nanoparticles. Zinc nanoparticles have been shown to be more effective in delaying ripening significantly by reducing weight and moisture loss and ensuring retention of fruit firmness. Further research is needed to understand their effect on other physicochemical properties of fruits.

Novel Clotrimazole and Vitis vinifera loaded chitosan nanoparticles: Antifungal and wound healing efficiencies

Chitosan integrated nanoparticles of clotrimazole and Egyptian Vitis vinifera juice extract was evaluated in order to maximize the antifungal activity and reduce the gross side effects. In the present study Egyptian Thompson Seedless Vitis vinifera and Clotrimazole (Cz) loaded chitosan nanoparticles (NCs/VJ/Cz) showed a promising antifungal effect with average inhibition zone diameters of 74 and 72 mm against Candida albicans and Aspergillus niger respectively. NCs/VJ /Cz was stable with significant drug entrapment efficiency reached 94.7%; PDI 0.24; zeta potential value + 31 and average size 35.4 nm diameter. Ex vivo and in vivo evaluation of skin retention, permeation and wound repair potentialities of NCs/VJ /Cz ointment was examined by experimental rats with wounded skin fungal infection. Data proved the ability of NCs/VJ /Cz to gradually release the drugs in a sustained manner with complete wound healing effect and tissue repair after 7 days administration. As a conclusion NCs/VJ /Cz ointment can be used as a novel anti-dermatophytic agent with high wound healing capacity.

Polysaccharide-based formulations as potential carriers for pulmonary delivery - A review of their properties and fates

Polysaccharides can be elite carriers for therapeutic molecules due to their versatility and low probability to trigger toxicity and immunogenic responses. Local and systemic therapies can be achieved through particle pulmonary delivery, a promising non-invasive alternative. Successful pulmonary delivery requires particles with appropriate flowability to reach alveoli and avoid premature clearance mechanisms. Polysaccharides can form micro-, nano-in-micro-, and large porous particles, aerogels, and hydrogels. Herein, the characteristics of polysaccharides used in drug formulations for pulmonary delivery are reviewed, providing insights into structure-function relationships. Charged polysaccharides can confer mucoadhesion, whereas the ability for specific sugar recognition may confer targeting capacity for alveolar macrophages. The method of particle preparation must be chosen considering the properties of the components and the delivery device to be utilized. The fate of polysaccharide-based carriers is dependent on enzyme-triggered hydrolytic and/or oxidative mechanisms, allowing their complete degradation and elimination through urine or reutilization of released monosaccharides.

Immunomodulatory effects of polysaccharides from marine algae for treating cancer, infectious disease, and inflammation

A significant rise in the occurrence and severity of adverse reactions to several synthetic drugs has fueled considerable interest in natural product-based therapeutics. In humans and animals, polysaccharides from marine microalgae and seaweeds have immunomodulatory effects. In addition, these polysaccharides may possess antiviral, anticancer, hypoglycemic, anticoagulant, and antioxidant properties. During inflammatory diseases, such as autoimmune diseases and sepsis, immunosuppressive molecules can serve as therapeutic agents. Similarly, molecules that participate in immune activation can induce immune responses against cancer and infectious diseases. We aim to discuss the chemical composition of the algal polysaccharides, namely alginate, fucoidan, ascophyllan, and porphyran. We also summarize their applications in the treatment of cancer, infectious disease, and inflammation. Recent applications of nanoparticles that are based on algal polysaccharides for the treatment of cancer and inflammatory diseases have also been addressed. In conclusion, these applications of marine algal polysaccharides could provide novel therapeutic alternatives for several diseases.

Bioactive Carbohydrate Polymers-Between Myth and Reality

Polysaccharides are complex macromolecules long regarded as energetic storage resources or as components of plant and fungal cell walls. They have also been described as plant mucilages or microbial exopolysaccharides. The development of glycosciences has led to a partial and difficult deciphering of their other biological functions in living organisms. The objectives of glycobiochemistry and glycobiology are currently to correlate some structural features of polysaccharides with some biological responses in the producing organisms or in another one. In this context, the literature focusing on bioactive polysaccharides has increased exponentially during the last two decades, being sometimes very optimistic for some new applications of bioactive polysaccharides, notably in the medical field. Therefore, this review aims to examine bioactive polysaccharide, taking a critical look of the different biological activities reported by authors and the reality of the market. It focuses also on the chemical, biochemical, enzymatic, and physical modifications of these biopolymers to optimize their potential as bioactive agents.

Relationship between the structure of a highly regular fucoidan from Fucus evanescens and its ability to form nanoparticles

Chitosan/fucoidan nanoparticles were created using two fucoidans from the Fucus evanescens algae. One of them was a regular fucoidan obtained for the first time from the alga harvested at the reproductive growth stage, using only standard extraction methods, without additional modifications. Its structure was established via NMR spectroscopy to consist of the repeating →3)-α-L-Fucp-(2,4SO3-)-(1 → 4)-α-L-Fucp-(2SO3-)-(1→ fragment. Such fragment also coustituted 55% of the other fucoidan's structure, however it also included long sequences of α-L-fucopyranose residues sulfated only at C2. The nanoparticles were re-dispersed in water and the influence of fucoidan/chitosan mass ratio on the nanoparticles' size and zeta potential was investigated. 3D models of the regular fucoidan and chitosan's sections were created and their molecular docking was performed, showing that either polymer could occupy the exterior of the complex, depending on their ratio. Thermodynamic parameters of fucoidan-chitosan binding process were accessed, with the results indicating that significant conformational changes of fucoidan and chitosan molecules take place during the interaction, presumably to allow for more effective binding.

Curcumin-laden dual-targeting fucoidan/chitosan nanocarriers for inhibiting brain inflammation via intranasal delivery

Curcumin can reduce the production of brain inflammatory mediators and symptoms of brain diseases. However, a large amount of free curcumin needs to be administered to achieve an effective level in the brain because of its poor water-solubility. Fucoidan and chitosan were reported to respectively target P-selectin and acidic microenvironment expressed by pathologically inflammatory cells/tissues. Herein, the self-assembly of chitosan and fucoidan which could encapsulate curcumin was developed to form the multi-stimuli-responsive nanocarriers, and their pathological pH- and P-selectin-responsive aspects were characterized. Through intranasal delivery to the brain, these curcumin-containing chitosan/fucoidan nanocarriers with dual pH-/P-selectin-targeting properties to the brain lesions improved drug delivery, distribution, and accumulation in the inflammatory brain lesions as evidenced by an augmented inhibitory effect against brain inflammation. This promising multifunctional nanocarrier with a novel drug-delivery route should allow potential clinical biomedical uses by neurosurgeon in the future.

Facilitated and Controlled Strontium Ranelate Delivery Using GCS-HA Nanocarriers Embedded into PEGDA Coupled with Decortication Driven Spinal Regeneration

BACKGROUND AND PURPOSE

Strontium ranelate (SrR) is an oral pharmaceutical agent for osteoporosis. In recent years, numerous unwanted side effects of oral SrR have been revealed. Therefore, its clinical administration and applications are limited. Hereby, this study aims to develop, formulate, and characterize an effective SrR carrier system for spinal bone regeneration.

METHODS

Herein, glycol chitosan with hyaluronic acid (HA)-based nanoformulation was used to encapsulate SrR nanoparticles (SrRNPs) through electrostatic interaction. Afterward, the poly(ethylene glycol) diacrylate (PEGDA)-based hydrogels were used to encapsulate pre-synthesized SrRNPs (SrRNPs-H). The scanning electron microscope (SEM), TEM, rheometer, Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) were used to characterize prepared formulations. The rabbit osteoblast and a rat spinal decortication models were used to evaluate and assess the developed formulation biocompatibility and therapeutic efficacy.

RESULTS

In vitro and in vivo studies for cytotoxicity and bone regeneration were conducted. The cell viability test showed that SrRNPs exerted no cytotoxic effects in osteoblast in vitro. Furthermore, in vivo analysis for new bone regeneration mechanism was carried out on rat decortication models. Radiographical and histological analysis suggested a higher level of bone regeneration in the SrRNPs-H-implanted groups than in the other experimental groups.

CONCLUSION

Local administration of the newly developed formulated SrR could be a promising alternative therapy to enhance bone regeneration in bone-defect sites in future clinical applications.

Development and characterization of soybean protein isolate and fucoidan nanoparticles for curcumin encapsulation

Curcumin (Cur) is a natural polyphenol with beneficial biological and pharmacological activities; however, it has limited applications owing to its low solubility and light sensitivity. The protein-polysaccharide complex can effectively embed lipid-soluble drugs to increase their stability and dispensability in aqueous solutions. Soybean protein isolate (Spi) and fucoidan (Fuc) were used as a polymer matrix, and core-shell nanoparticles were prepared to encapsulate Cur via electrostatic interaction under acidic and neutral conditions. The structure of the Spi-Fuc nanoparticles was studied via Fourier-transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. Concurrently, we evaluated the efficacy of the nanoparticles based on stability, drug loading rate, and simulated release. Our results showed that the Spi-Fuc nanoparticles (size, approximately 236.56 nm) had a spherical, core-shell structure and that they could effectively load Cur with an embedding efficiency of >95%; moreover, the system had long-term dispersion stability. Thus, we provide a simple method for Cur delivery, which can also be potentially used for delivering lipid-soluble active ingredients.

One-Step Reinforcement and Deacidification of Paper Documents: Application of Lewis Base—Chitosan Nanoparticle Coatings and Analytical Characterization

To delay acidification and deterioration during natural aging, deacidification and reinforcement of paper manuscripts have been the most important technologies to prolong the life of objects. Herein, a novel approach for the conservation of paper manuscripts is proposed using chitosan nanoparticles as Lewis base that leads to both deacidification and strengthening of paper in one-step. Chitosan nanoparticles were prepared through physical ball grinding method and characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer (LPSA), Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). To evaluate the resistance of chitosan nanoparticle coating, the mechanical properties of paper after artificial aging were evaluated using dry heat and hygrothermal accelerated aging methods. The SEM, EDX, and X-ray Photoelectron Spectroscopy (XPS) were used to analyze the interaction mechanism between chitosan and Shuxuan paper. The results show that the coated paper had superior durability with respect to pH, tensile strength, and folding endurance. There was a presence of protonated amines in the form of ammonium salts due to ionic bindings with free H+ in the acidified paper, and the remaining –NH2 could be used as a base reserve. Finally, the resulting coated papers displayed good antibacterial properties.

Green Synthesis of Antileishmanial and Antifungal Silver Nanoparticles Using Corn Cob Xylan as a Reducing and Stabilizing Agent

Corn cob is an agricultural byproduct that produces an estimated waste burden in the thousands of tons annually, but it is also a good source of xylan, an important bioactive polysaccharide. Silver nanoparticles containing xylan (nanoxylan) were produced using an environmentally friendly synthesis method. To do this, we extracted xylan from corn cobs using an ultrasound technique, which was confirmed by both chemical and NMR analyses. This xylan contained xylose, glucose, arabinose, galactose, mannose, and glucuronic acid in a molar ratio of 50:21:14:9:2.5:2.5, respectively. Nanoxylan synthesis was analyzed using UV-vis spectroscopy at kmax = 469 nm and Fourier transform infrared spectroscopy (FT-IR), which confirmed the presence of both silver and xylan in the nanoxylan product. Dynamic light scattering (DLS) and atomic force microscopy (AFM) revealed that the nanoxylan particles were ~102.0 nm in size and spherical in shape, respectively. DLS also demonstrated that nanoxylan was stable for 12 months and coupled plasma optical emission spectrometry (ICP-OES) showed that the nanoxylan particles were 19% silver. Nanoxylan reduced Leishmania amazonensis promastigote viability with a half maximal inhibitory concentration (IC50) value of 25 μg/mL, while xylan alone showed no effective. Additionally, nanoxylan exhibited antifungal activity against Candida albicans (MIC = 7.5 μg/mL), C. parapsilosis (MIC = 7.5 μg/mL), and Cryptococcus neoformans (MIC = 7.5 μg/mL). Taken together, these data suggest that it is possible to synthesize silver nanoparticles using xylan and that these nanoxylan exert improved antileishmanial and antifungal activities when compared to the untreated polysaccharide or silver nitrate used for their synthesis. Thus, nanoxylan may represent a promising new class of antiparasitic agents for use in the treatment of these microorganisms.

Mucoadhesive and pH responsive fucoidan-chitosan nanoparticles for the oral delivery of methotrexate

Considering the potential of mucoadhesive properties of nanoparticles in oral delivery, this work describes the preparation and characterization of fucoidan/chitosan nanoparticles loaded with methotrexate (MTX) intended to lung cancer therapy. The nanoparticles were produced and characterized in terms of size, surface charge, entrapment efficiency, and morphology. The size of the developed nanoparticles was around 300 nm, the zeta potential value was negative (ca. -30 mV), revealing a low tendency to aggregate. The self-assembled fucoidan/chitosan nanoparticles were stable at acidic pH (1.6-5.2), without disintegration under pH 6-7.4, revealing resistance through the gastrointestinal tract, and were found to be mucoadhesive suggesting ability to enhance drug oral bioavailability. Lung cancer cells quickly internalized the developed nanoparticles. Moreover, MTX-loaded fucoidan/chitosan nanoparticles up to 245 μg mL-1 in polymer equivalent to 23.5 μg mL-1 of MTX were safe towards fibroblasts but hampered lung cancer cell proliferation mediated by an apoptotic process. MTX-loaded nanoparticles were 7-fold more effective in inhibiting lung cancer cells proliferation than the free drug, showing the potential of fucoidan-chitosan nanoparticles to improve the cytotoxicity of free methotrexate on A549 lung cancer cells. These results also demonstrate that fucoidan/chitosan nanoparticles may provide a suitable platform for poor-water soluble compounds' oral delivery.

The Potential of Fucose-Containing Sulfated Polysaccharides As Scaffolds for Biomedical Applications

Marine environments have a high quantity and diversity of sulfated polysaccharides. In coastal regions brown algae are the most abundant biomass producers and their cell walls have fucosecontaining sulfated polysaccharides (FCSP), known as fucans and/or fucoidans. These sulfated compounds have been widely researched for their biomedical properties, namely the immunomodulatory, haemostasis, pathogen inhibition, anti-inflammatory capacity, and antitumoral. These activities are probably due to their ability to mimic the carbohydrate moieties of mammalian glycosaminoglycans. Therefore, the FCSP are interesting compounds for application in health-related subjects, mainly for developing scaffolds for delivery systems or tissue regeneration. FCSP showed potential for these applications also due to their ability to form stable 3D structures with other polymers able to entrap therapeutic agents or cell and growth factors, besides their biocompatibility and biodegradability. However, for the clinical use of these biopolymers well-defined reproducible molecules are required in order to accurately establish relationships between structural features and human health applications.

Marine Polysaccharides in Pharmaceutical Applications: Fucoidan and Chitosan as Key Players in the Drug Delivery Match Field

The use of marine-origin polysaccharides has increased in recent research because they are abundant, cheap, biocompatible, and biodegradable. These features motivate their application in nanotechnology as drug delivery systems; in tissue engineering, cancer therapy, or wound dressing; in biosensors; and even water treatment. Given the physicochemical and bioactive properties of fucoidan and chitosan, a wide range of nanostructures has been developed with these polysaccharides per se and in combination. This review provides an outline of these marine polysaccharides, including their sources, chemical structure, biological properties, and nanomedicine applications; their combination as nanoparticles with descriptions of the most commonly used production methods; and their physicochemical and biological properties applied to the design of nanoparticles to deliver several classes of compounds. A final section gives a brief overview of some biomedical applications of fucoidan and chitosan for tissue engineering and wound healing.

Increased ROS Scavenging and Antioxidant Efficiency of Chlorogenic Acid Compound Delivered via a Chitosan Nanoparticulate System for Efficient In Vitro Visualization and Accumulation in Human Renal Adenocarcinoma Cells

Naturally existing Chlorogenic acid (CGA) is an antioxidant-rich compound reported to act a chemopreventive agent by scavenging free radicals and suppressing cancer-causing mechanisms. Conversely, the compound’s poor thermal and pH (neutral and basic) stability, poor solubility, and low cellular permeability have been a huge hindrance for it to exhibit its efficacy as a nutraceutical compound. Supposedly, encapsulation of CGA in chitosan nanoparticles (CNP), nano-sized colloidal delivery vector, could possibly assist in enhancing its antioxidant properties, in vitro cellular accumulation, and increase chemopreventive efficacy at a lower concentration. Hence, in this study, a stable, monodispersed, non-toxic CNP synthesized via ionic gelation method at an optimum parameter (600 µL of 0.5 mg/mL of chitosan and 200 µL of 0.7 mg/mL of tripolyphosphate), denoted as CNP°, was used to encapsulate CGA. Sequence of physicochemical analyses and morphological studies were performed to discern the successful formation of the CNP°-CGA hybrid. Antioxidant property (studied via DPPH (1,1-diphenyl-2-picrylhydrazyl) assay), in vitro antiproliferative activity of CNP°-CGA, and in vitro accumulation of fluorescently labeled (FITC) CNP°-CGA in cancer cells were evaluated. Findings revealed that successful formation of CNP°-CGA hybrid was reveled through an increase in particle size 134.44 ± 18.29 nm (polydispersity index (PDI) 0.29 ± 0.03) as compared to empty CNP°, 80.89 ± 5.16 nm (PDI 0.26 ± 0.01) with a maximal of 12.04 μM CGA loaded per unit weight of CNP° using 20 µM of CGA. This result correlated with Fourier-Transform Infrared (FTIR) spectroscopic analysis, transmission Electron Microscopy (TEM) and field emission scanning (FESEM) electron microscopy, and ImageJ evaluation. The scavenging activity of CNP°-CGA (IC₅₀ 5.2 ± 0.10 µM) were conserved and slightly higher than CNP° (IC₅₀ 6.4±0.78 µM). An enhanced cellular accumulation of fluorescently labeled CNP°-CGA in the human renal cancer cells (786-O) as early as 30 min and increased time-dependently were observed through fluorescent microscopic visualization and flow cytometric assessment. A significant concentration-dependent antiproliferation activity of encapsulated CGA was achieved at IC₅₀ of 16.20 µM as compared to CGA itself (unable to determine from the cell proliferative assay), implying that the competent delivery vector, chitosan nanoparticle, is able to enhance the intracellular accumulation, antiproliferative activity, and antioxidant properties of CGA at lower concentration as compared to CGA alone.

Possibilities of Fucoidan Utilization in the Development of Pharmaceutical Dosage Forms

Fucoidan is a polysaccharide built from L-fucose molecules. The main source of this polysaccharide is the extracellular matrix of brown seaweed (Phaeophyta), but it can be also isolated from invertebrates such as sea urchins (Echinoidea) and sea cucumbers (Holothuroidea). Interest in fucoidan is related to its broad biological activity, including possible antioxidant, anti-inflammatory, antifungal, antiviral or antithrombotic effects. The potential application of fucoidan in the pharmaceutical technology is also due to its ionic nature. The negative charge of the molecule results from the presence of sulfate residues in the C-2 and C-4 positions, occasionally in C-3, allowing the formation of complexes with other oppositely charged molecules. Fucoidan is non-toxic, biodegradable and biocompatible compound approved by Food and Drug Administration (FDA) as Generally Recognized As Safe (GRAS) category as food ingredient. Fucoidan plays an important role in the pharmaceutical technology, so in this work aspects concerning its pharmaceutical characteristics and designing of various dosage forms (nanoparticles, liposomes, microparticles, and semisolid formulations) with fucoidan itself and with its combinations with other polymers or components that give a positive charge were reviewed. Advantages and limitations of fucoidan utilization in the pharmaceutical technology were also discussed.

Free Radical Scavenging and Some Pharmaceutical Utilities of Nanoparticles in the Recent Scenario

BACKGROUND

Nanopharmaceuticals have rapidly emerged as a means to cure several diseases. There are numerous reports describing the development and application of nanopharmaceuticals. Here, we discussed nanoparticle synthesis and the mechanisms to scavenge free radicals. We also discuss their major properties and list several commercially available nanomedicines.

RESULTS

Reactive oxygen and hydrogen species are formed during normal metabolism, and excessive reactive species can damage proteins, lipids, and DNA and cause disease. Plant- and microbe-based nanoparticles, which can protect tissues from free radical damage, have recently gained research momentum because they are inexpensive and safe.

CONCLUSION

Synthetic and biocompatible nanoparticles exhibit antioxidant, antidiabetic, anti-inflammatory, and anticancer properties, which can be used to treat several diseases. Further studies are needed to investigate their sizes, dose-dependent activities, and mechanisms of action.

Application of pH-Responsive Fucoidan/Chitosan Nanoparticles to Improve Oral Quercetin Delivery

Polymeric nanoparticles based on fucoidan and chitosan were developed to deliver quercetin as a novel functional food. Through the polyelectrolyte self-assembly method, fucoidan/chitosan (F/C) nanoparticles were obtained with three different weight ratios (1/1, 3/1, and 5/1). The content of quercetin in the fucoidan/chitosan nanoparticles was in the range 110 ± 3 to 335 ± 4 mg·mL^-1, with the increase of weight ratio of fucoidan to chitosan in the nanoparticle. Physicochemically stable nanoparticles were obtained with a particle size within the 300⁻400 nm range and surface potential higher than +30 mV for the 1F/1C ratio nanoparticle and around -30 mV for the 3F/1C and 5F/1C ratios nanoparticles. The 1F/1C ratio nanoparticle became larger and more unstable as the pH increased from 2.5 to 7.4, while the 3F/1C and 5F/1C nanoparticles retained their initial characteristics. This result indicates that the latter nanoparticles were stable along the gastrointestinal tract. The quercetin-loaded fucoidan/chitosan nanoparticles showed strong antioxidant activity and controlled release under simulated gastrointestinal environments (in particular for the 3F/1C and 5F/1C ratios), preventing quercetin degradation and increasing its oral bioavailability.

Macroalgal Polysaccharides in Biomimetic Nanodelivery Systems

BACKGROUND

Imitating nature in the design of bio-inspired drug delivery systems resulted in several success stories. However, the practical application of biomimicry is still largely unrealized owing to the fact that we tend to copy the shape more often than the whole biology. Interesting chemistry of polysaccharides provides endless possibilities for drug complex formation and creation of delivery systems with diverse morphological and surface properties. However, the type of biological response, which may be induced by these systems, remains largely unexploited.

METHODS

Considering the most current research for the given topic, in this review, we will try to present the integrative approaches for the design of biomimetic DDS's with improved therapeutic or theranostic effects based on different algal polysaccharides that exert multiple biological functions.

RESULTS

Algal polysaccharides may provide building blocks for bioinspired drug delivery systems capable of supporting the mechanical properties of nanomedicines and mimicking various biological processes by molecular interactions at the nanoscale. Numerous research studies demonstrate the efficacy and safety of multifunctional nanoparticles integrating several functions in one delivery system, composed of alginate, carrageenan, ulvan, fucoidan and their derivatives, intended to be used as bioartificial microenvironment or for diagnosis and therapy of different diseases.

CONCLUSION

Nanodimensional structure of polysaccharide DDS's shows substantial influence on the bioactive motifs potential availability for interaction with a variety of biomolecules and cells. Evaluation of the nano dimensional structure-activity relationship is crucial for unlocking the full potential of the future application of polysaccharide bio-mimicking DDS in modern diagnostic and therapeutic procedures.

Spray-dried fucoidan microparticles for pulmonary delivery of antitubercular drugs

Pulmonary tuberculosis accounts for 80% of cases and the delivery of antitubercular drugs into the lungs allows targeting the infected organ and, possibly, reducing systemic drug toxicity. This work aimed at using fucoidan as matrix of inhalable microparticles that associate two first-line antitubercular drugs, for an application in pulmonary tuberculosis therapy. Fucoidan is composed of fucose and sulphated sugar residues, moieties described as being recognised by surface receptors of alveolar macrophages, which host mycobacteria. Inhalable fucoidan microparticles loaded with antitubercular drugs were successfully produced with high association efficiencies of either isoniazid (95%) or rifabutin (81%). The microparticles evidenced no cytotoxicity on lung epithelial cells (A549). However, rifabutin-loaded microparticles showed a certain degree of toxicity on macrophage-like cells (THP-1) at the highest tested concentration (1 mg/mL). Furthermore, microparticles showed favourable aerodynamic properties for deep lung delivery (MMAD 2.0-3.8 µm) and, thus, show potential for an application as inhalable tuberculosis therapy.

Preparation, Characterization and Biological Applications of Biosynthesized Silver Nanoparticles with Chitosan-Fucoidan Coating

Silver nanoparticles (AgNPs) are gaining a great deal of attention in biomedical applications due to their unique physicochemical properties. In this study, green synthesis of AgNPs was developed using seaweed polysaccharide fucoidan. The AgNPs were further coated with chitosan to form an electrolyte complex on the surface. The developed chitosan⁻fucoidan complex-coated AgNPs were characterized using UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). FT-IR results suggested strong polyelectrolyte complexation between fucoidan and chitosan. The developed chitosan⁻fucoidan complex-coated AgNPs significantly inhibited microbial growth. Moreover, the AgNPs showed efficient anticancer activity in human cervical cancer cells (HeLa). This study demonstrated that chitosan⁻fucoidan complex-coated AgNPs hold high potential for food and cosmeceutical applications.

Synthesis, coating, and drug-release of hydroxyapatite nanoparticles loaded with antibiotics

Post-surgery infections are considered the most challenging complication in the orthopedic and dental field. The local release of antibiotics is evidently highly efficient in delivering the drug to the vicinity of the infected area without the risk of systemic toxicity. Bioactive materials, such as hydroxyapatite (HAp) among other calcium phosphates, are reputed as superior antibiotic vehicles, and combine drug-delivery properties and enhanced osteoconductivity. Here, we report on the single-step electrophoretic deposition (EPD) of drug-loaded HAp nanoparticles (NPs) on titanium implants. This approach provides a purely bioactive coating with drug delivery properties in a simple, economic, and fast process. We synthesized pure HAp NPs with 12.5% and 12.8% loading weight percentages of gentamicin sulfate (Gs) and ciprofloxacin (Cip), and electrophoretically deposited them on a titanium substrate. Furthermore, we co-deposited Gs-HAp and Cip-HAp in one-step to yield a drug-loaded system consisting of two types of antibiotics. The drug-loaded NPs as well as the coatings were carefully characterized. The release profiles of the Gs-HAp and Cip-HAp NP coatings showed prolonged release of up to 10 and 25 days, respectively. The bioactivity test revealed superior bioactivity with enhanced precipitation of HAp crystals along with inorganic minerals, such as Mg²⁺, Na⁺, and Cl^-. The antibacterial in vitro tests of the Cip and Gs-HAp coatings showed efficient inhibition of Pseudomonas aeruginosa bacteria.

Physiological responses of cultured bovine granulosa cells to elevated temperatures under low and high oxygen in the presence of different concentrations of melatonin

Our understanding of the effects of temperature on granulosa cell (GC) physiology is primarily limited to in vitro studies conducted under atmospheric (∼20% O₂) conditions. In the current series of factorial experiments we identify important effects of O₂ level (i.e. 5% vs 20% O₂) on GC viability and steroidogenesis, and go onto report effects of standard (37.5 °C) vs high (40.0 °C) temperatures under more physiologically representative (i.e. 5%) O₂ levels in the presence of different levels of melatonin (0, 20, 200 and 2000 pg/ml); a potent free-radical scavenger and abundant molecule within the ovarian follicle. Cells aspirated from antral (4-6 mm) follicles were cultured in fibronectin-coated wells using serum-free M199 for up to 144 h. At 37.5 °C viable cell number was enhanced and luteinization reduced under 5 vs 20% O₂. Oxygen level interacted (P < 0.001) with time in culture to affect aromatase activity and cell estradiol (E₂) production (pg/mL/10⁵ cells). These decreased between 48 and 96 h for both O₂ levels but increased again by 144 h for cells cultured under 5% but not 20% O₂. Progesterone (P₄) concentration (ng/mL/10⁵ cells) was greater (P < 0.001) under 20 vs 5% O₂ at 96 and 144 h. Cell number increased (P < 0.01) with time in culture under 5% O₂ irrespective of temperature. However, higher doses of melatonin increased viable cell number at 40.0 °C but reduced viable cell number at 37.5 °C (P = 0.004). Melatonin also reduced (P < 0.001) ROS generation at both O₂ levels across all concentrations. E₂ increased with time in culture at both temperatures under 5% O₂, however P₄ declined between 96 and 144 h at 40.0 but not 37.5 °C. Furthermore, melatonin interacted (P < 0.001) with temperature in a dose dependent manner to increase P₄ at 37.5 °C but to reduce P₄ at 40.0 °C. Transcript expression for HSD3B1 paralleled temporal changes in P₄ production, and those for HBA were greater at 5% than 20% O₂, suggesting that hemoglobin synthesis is responsive to changes in O₂ level. In conclusion, 5% O₂ enhances GC proliferation and reduces luteinization. Elevated temperatures under 5% O₂ reduce GC proliferation and P₄ production. Melatonin reduces ROS generation irrespective of O₂ level and temperature, but interacts with temperature in a dose dependent manner to influence GC proliferation and luteinization.