Recent Biomedical Approaches for Chitosan Based Materials as Drug Delivery Nanocarriers

Harnessing the immunomodulatory potential of chitosan and its derivatives for advanced biomedical applications

The success of biomaterial applications in medicine, particularly in tissue engineering, relies on achieving a balance between promoting tissue regeneration and controlling the immune response. Due to its natural origin, high biocompatibility, and versatility, chitosan has emerged as a promising biomaterial especially for immunomodulation purposes. Immunomodulation, refers to the deliberate alteration of the immune system's activity to achieve a desired therapeutic effect either by enhancing or suppressing the function of specific immune cells, signaling pathways, or cytokine production. This modulation opens up the unlimited possibilities for the use of biomaterials, especially about the use of natural polymers such as chitosan. Although numerous chitosan-based immunoregulatory strategies have been demonstrated over the past two decades, the lack of in-depth exploration hinders the full potential of strategies that include chitosan and its derivatives in biomedical applications. Thus, in this review, the possible immunomodulatory effects of chitosan, chitosan derivatives and their potential combined with various agents and therapies are investigated in detail. Moreover, this report includes agents for localized immune response control, chitosan-based strategies with complementary immunomodulatory properties to create synergistic effects that will influence the success of cell therapies for enhanced tissue acceptance and regeneration. Finally, the challenges and outlook of chitosan-based therapies as a powerful tool for improving immunomodulatory applications are discussed for paving the way for further studies.

Natural-Synthetic Hybrid Nanostructures Formed Through the Interaction of Chitosan with Carboxylate-Ended PNIPAM: Structure and Curcumin Encapsulation

Chitosan is widely used in drug delivery applications, due to its biocompatibility, bio-degradability, and low toxicity. Nevertheless, its properties can be enhanced through the physical or chemical modification of its amino and hydroxyl groups. This work explores the electrostatic complexation of two chitosan samples of differing lengths with two poly(N-isopropylacrylamide) (PNIPAM) homopolymers of different molecular weight carrying a chargeable carboxyl end group. This interaction enables the electrostatic binding of PNIPAM side chains onto the chitosan backbone through the amino groups, and could be considered as an alternative grafting method. Dynamic and electrophoretic light scattering techniques were employed in order to study the solution/dispersion properties of the formed complexes as a function of the PNIPAM concentration, or, equivalently, the molar/charge ratio of the two components. The obtained results revealed that their mass, size, and charge mostly depend on the length of the two individual constituents, as well as their mixing ratio. Furthermore, their response to changes in their environment, namely temperature and ionic strength, was also examined, demonstrating the effect of either the thermoresponsiveness of PNIPAM or the electrostatic charge screening, respectively. Fluorescence spectroscopy, utilizing pyrene as a probe, provided information regarding the hydrophobicity of the formed complexes, while images from scanning transmission electron and atomic force microscopies further elucidated their morphology, which was found to be closely related to that of the corresponding chitosan molecule. Finally, their potential as drug delivery vehicles was also investigated, utilizing curcumin as a model drug at various loading concentrations.

Development and characterization of caffeine-loaded nanoliposomes decorated by cationic amylose and cationic amylose- menthol inclusion complex coatings; a novel oral co-delivery system

Nanoliposomes (NLPs) have evolved as compelling carriers for loading bioactive compounds. To improve the phospholipid bilayer membrane stability, caffeine-loaded NLPs were coated with cationic amylose (CA) and CA-menthol inclusion complexes (CAMICs). The zeta potential results indicated an electrostatic attraction between CA and the negatively charged NLPs. Observations from dynamic light scattering, atomic force microscopy, and Fourier transform infrared spectroscopy demonstrated the efficient deposition of both CA and CAMICs onto the surface of NLPs without altering their spherical shape. Raman spectra and X-ray diffraction patterns indicated that both CA and CAMICs can decrease membrane fluidity and enhance lipid packing laterally. Additional assessment through thermogravimetric analysis revealed that the coating of NLPs, particularly with CAMICs, protected caffeine against thermal degradation. These coated NLPs show promise for formulation advancement, facilitating the simultaneous delivery of functional compounds.

Enhancing photodynamic and radionuclide therapy by small interfering RNA (siRNA)-RAD51 transfection via self-emulsifying delivery systems (SNEDDS)

BACKGROUND AIMS

Gene-silencing by small interfering RNA (siRNA) is an attractive therapy to regulate cancer death, tumor recurrence or metastasis. Because siRNAs are easily degraded, it is necessary to develop transport and delivery systems to achieve efficient tumor targeting. Self-nanoemulsifying systems (SNEDDS) have been successfully used for pDNA transport and delivery, so they may be useful for siRNA. The aim of this work is to introduce siRNA-RAD51 into a SNEDDS prepared with Phospholipon-90G, Labrafil-M1944-CS and Cremophor-RH40 and evaluate its efficacy in preventing homologous recombination of DNA double-strand breaks caused by photodynamic therapy (PDT) and ionizing radiation (IR).

METHODS

The siRNA-RAD51 was loaded into SNEDDS using chitosan. Transfection capacity was estimated by comparison with Lipofectamine-2000.

RESULTS

SNEDDS(siRNA-RAD51) induced gene silencing effect on the therapies evaluated by cell viability and clonogenic assays using T47D breast cancer cells.

CONCLUSIONS

SNEDDS(siRNA-RAD51) shown to be an effective siRNA-delivery system to decrease cellular resistance in PDT or IR.

Stability, challenges, and prospects of chitosan for the delivery of anticancer drugs and tissue regenerative growth factors

Chitosan, a biopolymer derived from chitin, offers significant potential for regulated anticancer drug administration and tissue regeneration growth factors, owing to its biocompatibility, low toxicity, biodegradability, and little immunogenicity. Moreover, its structure can be extensively modified, for example, to create scaffolds, hydrogels, nanoparticles, and membranes, allowing it to be engineered precisely to achieve specific outcomes However, the therapeutic utilisation of chitosan is impeded by significant challenges, such as its inadequate hemocompatibility, durability, and uniformity in commercial manufacturing. Additionally, there is insufficient research offering a thorough examination of the capabilities, limitations, and challenges related to chitosan as carriers for anticancer drugs and growth factors. This article examines the stability, challenges, and advanced application of chitosan as a drug carrier in anti-cancer therapy and growth factor delivery. The problems of unregulated chitosan degradation arising from unsuitable storage conditions are considered and potential solutions, and areas for future research, are proposed to deal with such problems. Consequently, this review is expected to be highly valuable for aspiring scientists studying chitosan-related systems for delivery of anti-cancer drugs and growth factors.

Novel antimicrobial biodegradable composite films as packaging materials based on shellac/chitosan, and ZnAl2O4 or CuAl2O4 spinel nanoparticles

ZnAl2O4 and CuAl2O4 spinel nanoparticles were prepared by a modified Pechini method and used with the natural chitosan (CS) and shellac (SH) polymers to form novel composite membranes as promising food packaging materials. The selection of ZnAl2O4 and CuAl2O4 spinel nanoparticles was based on their antibacterial characteristics, availability, and economy. Using a straightforward and adaptable solution mixing and casting method, the bio-composites were created. The mechanical, physical, antibacterial, homogeneity and air permeability properties of composite films were investigated. The film structure was evaluated in terms of component interactions using FTIR spectra. The addition of 10% SH increased the tensile strength, percentage strain at maximum load, Young's modulus, and burst strength by 114-101%, 3.6-8.4, 103-119, and 179-153% for low and middle M.wt./CS respectively. Chitosan/shellac-CuAl2O4 composite has superior properties compared to ZnAl2O4 composite. In general, 0.05% spinel provides a composite having better qualities than that of 0.1 additions. Middle M.wt. chitosan provides a composite with superior properties compared to that of low M.wt. The incorporation of ZnAl2O4 or CuAl2O4 enhanced the thermal stability of the SH/CS composite. ZnAl2O4 provides superior thermal stability than CuAl2O4. When shellac/CS film structure is treated with the previously indicated ZnAl2O4 or CuAl2O4 formulation, the % swelling decreases along with an increasing in the gel fraction. The antimicrobial assessment using inhibition zone diameter and shake flask methods showed that a composite of 1:9 shellac/chitosan/0.05% of CuAl2O4 exerted the highest Gram-positive antibacterial activity against B. mycoides (21 mm), and C. albicans (22 mm). So, these enhancements make chitosan/shellac/ZnAl2O4 or CuAl2O4 composite films a good alternative to producing food packaging materials.

Advancements of Biomacromolecular Hydrogel Applications in Food Nutrition and Health

Hydrogels exhibit remarkable degradability, biocompatibility and functionality, which position them as highly promising materials for applications within the food and pharmaceutical industries. Although many relevant studies on hydrogels have been reported in the chemical industry, materials, and other fields, there have been few reviews on their potential applications in food nutrition and human health. This study aims to address this gap by reviewing the functional properties of hydrogels and assessing their value in terms of food nutrition and human health. The use of hydrogels in preserving bioactive ingredients, food packaging and food distribution is delved into specifically in this review. Hydrogels can serve as cutting-edge materials for food packaging and delivery, ensuring the preservation of nutritional activity within food products, facilitating targeted delivery of bioactive compounds and regulating the digestion and absorption processes in the human body, thereby promoting human health. Moreover, hydrogels find applications in in vitro cell and tissue culture, human tissue repair, as well as chronic disease prevention and treatment. These broad applications have attracted great attention in the fields of human food nutrition and health. Ultimately, this paper serves as a valuable reference for further utilization and exploration of hydrogels in these respective fields.

Anti-fungal peptides: an emerging category with enthralling therapeutic prospects in the treatment of candidiasis

Candida infections, particularly invasive candidiasis, pose a serious global health threat. Candida albicans is the most prevalent species causing candidiasis, and resistance to key antifungal drugs, such as azoles, echinocandins, polyenes, and fluoropyrimidines, has emerged. This growing multidrug resistance (MDR) complicates treatment options, highlighting the need for novel therapeutic approaches. Antifungal peptides (AFPs) are gaining recognition for their potential as new antifungal agents due to their diverse structures and functions. These natural or recombinant peptides can effectively target fungal virulence and viability, making them promising candidates for future antifungal development. This review examines infections caused by Candida species, the limitations of current antifungal treatments, and the therapeutic potential of AFPs. It emphasizes the importance of identifying novel AFP targets and their production for advancing treatment strategies. By discussing the therapeutic development of AFPs, the review aims to draw researchers' attention to this promising field. The integration of knowledge about AFPs could pave the way for novel antifungal agents with broad-spectrum activity, reduced toxicity, targeted action, and mechanisms that limit resistance in pathogenic fungi, offering significant advancements in antifungal therapeutics.

Recent advances in modified chitosan-based drug delivery systems for transmucosal applications: A comprehensive review

Recently, transmucosal drug delivery systems (TDDSs) have been extensively studied because they protect therapeutic agents from degradation; improve drug residence time at the mucosal membranes; and facilitate sustained drug release for a prolonged period. Chitosan is a well-researched polymeric excipient due to its biocompatibility, non-toxicity, biodegradability, mucoadhesive, antimicrobial, and low immunogenicity. Its limited mucoadhesiveness in the physiological environment necessitated its chemical modification. This review highlights the recent advances in the chemical modification of chitosan with various chemical groups to generate various functionalized chitosan derivatives, such as thiolated, acrylated, methacrylated, boronated, catechol, and maleimide-functionalized chitosans with superior mucoadhesive capabilities compared to the parent chitosan. Moreover, it presents the different prepared dosage forms, such as tablets, hydrogels, films, micro/nanoparticles, and liposomes/niosomes for drug administration within various mucosal routes including oral, buccal, nasal, ocular, colonic, intravesical, and vaginal routes. The reported data from preclinical studies of these pharmaceutical formulations have revealed the controlled and target-specific delivery of therapeutics because of their formation of covalent bonds with thiol groups on the mucosal surface. All functionalized chitosan derivatives exhibited long drug residence time on mucosal surfaces and sustainable drug release with excellent cellular permeability, drug efficacy, and biocompatibility. These promising data could be translated from the research laboratories to the clinics with consistent and intensive research effort.

Chitosan and liposomal delivery systems for epicatechin or propyl gallate targeting localized treatment of vulvovaginal candidiasis

Natural polyphenols are promising alternatives to antifungals for novel treatments of vulvovaginal candidiasis (VVC) in an era of antimicrobial resistance. However, polyphenols are poorly soluble and prone to degradation. To overcome their limitations, we propose incorporation in liposomes. The study aimed to develop chitosan and liposome comprising delivery systems for epicatechin (EC) or propyl gallate (PG) as treatment of VVC. EC was selected for its antioxidative properties and PG as an ester of antifungal gallic acid. To improve formulation retention at vaginal site, mucoadhesive chitosan was introduced into formulation as liposomal surface coating or hydrogel due to intrinsic antifungal properties. These polyphenol-loaded liposomes exhibited an average size of 125 nm with a 64 % entrapment efficiency (for both polyphenols). A sustained in vitro polyphenol release was seen from liposomes, particularly in chitosan hydrogel (p < 0.01 or lower). Viscosity was evaluated since increased viscosity upon mucin contact indicated adhesive bond formation between chitosan and mucin confirming mucoadhesiveness of formulations. Antifungal activity was evaluated by the broth microdilution method on Candida albicans CRM-10231. Unlike PG, incorporation of EC in liposomes enabled antifungal activity. Fungicidal activity of chitosan was confirmed both when used as liposomal coating material and as hydrogel vehicle.

Improving the bioavailability and therapeutic efficacy of felodipine for the control of diabetes-associated atherosclerosis: In vitro and in vivo characterization

Felodipine has proven to be effective as an atherosclerosis therapy because it increases blood flow to the vessel wall. However, the poor solubility, low bioavailability, and hepatic first-pass metabolism of oral felodipine compromise its therapeutic effectiveness. The study's goal is to create a nasal pH-sensitive hydrogel of felodipine-loaded invasomes (IPHFI) that will improve felodipine's release, permeation, bioavailability, and efficacy as a potential diabetes-associated atherosclerosis therapy. According to the pre-formulation study, the felodipine-loaded invasomes formulation composed of phospholipid (3%w/v), cholesterol (0.16%w/v), ethanol (3%v/v) and cineole (1%v/v) was chosen as the optimum formulation. The optimum formulation was characterized in vitro and then mixed with a mixture of chitosan and glyceryl monooleate to make the IPHFI formulation. The IPHFI formulation enhanced the release and permeation of felodipine by 2.99 and 3-fold, respectively. To assess the efficacy and bioavailability of the IPHFI formulation, it was studied in vivo using an experimental atherosclerosis rat model. Compared to oral free felodipine, the nasal administration of the IPHFI formulation increased the bioavailability by 3.37-fold and decreased the serum cholesterol, triglycerides, LDL, and calcification score by 1.56, 1.53, 1.80, and 1.18 ratios, respectively. Thus, nasal IPHFI formulation may represent a promising diabetes-associated atherosclerosis therapy.

Materials based on biodegradable polymers chitosan/gelatin: a review of potential applications

Increased mass manufacturing and the pervasive use of plastics in many facets of daily life have had detrimental effects on the environment. As a result, these worries heighten the possibility of climate change due to the carbon dioxide emissions from burning conventional, non-biodegradable polymers. Accordingly, biodegradable gelatin and chitosan polymers are being created as a sustainable substitute for non-biodegradable polymeric materials in various applications. Chitosan is the only naturally occurring cationic alkaline polysaccharide, a well-known edible polymer derived from chitin. The biological activities of chitosan, such as its antioxidant, anticancer, and antimicrobial qualities, have recently piqued the interest of researchers. Similarly, gelatin is a naturally occurring polymer derived from the hydrolytic breakdown of collagen protein and offers various medicinal advantages owing to its unique amino acid composition. In this review, we present an overview of recent studies focusing on applying chitosan and gelatin polymers in various fields. These include using gelatin and chitosan as food packaging, antioxidants and antimicrobial properties, properties encapsulating biologically active substances, tissue engineering, microencapsulation technology, water treatment, and drug delivery. This review emphasizes the significance of investigating sustainable options for non-biodegradable plastics. It showcases the diverse uses of gelatin and chitosan polymers in tackling environmental issues and driving progress across different industries.

Current status and prospects of gelatin and its derivatives in oncological applications: Review

Treating cancer remains challenging due to the substantial side effects and unfavourable pharmacokinetic characteristics of antineoplastic medications, despite the progress made in comprehending the properties and actions of tumour cells in recent years. The advancement of biomaterials, such as stents, implants, personalised drug delivery systems, tailored grafts, cell sheets, and other transplantable materials, has brought about a significant transformation in healthcare and medicine in recent years. Gelatin is a very adaptable natural polymer that finds extensive application in healthcare-related industries owing to its favourable characteristics, including biocompatibility, biodegradability, affordability, and the presence of accessible chemical groups. Gelatin is used as a biomaterial in the biomedical sector for the creation of drug delivery systems (DDSs) since it may be applied to various synthetic procedures. Gelatin nanoparticles (NPs) have been extensively employed as carriers for drugs and genes, specifically targeting diseased tissues such as cancer, tuberculosis, and HIV infection, as well as treating vasospasm and restenosis. This is mostly due to their biocompatibility and ability to degrade naturally. Gelatins possess a diverse array of potential applications that require more elucidation. This review focuses on the use of gelatin and its derivatives in the diagnosis and treatment of cancer. The advancement of biomaterials and bioreactors, coupled with the increasing understanding of emerging applications for biomaterials, has enabled progress in enhancing the efficacy of tumour treatment.

Exploring the Biomedical Frontiers of Plant-Derived Nanoparticles: Synthesis and Biological Reactions

As contemporary technology advances, scientists are striving to identify new approaches to managing several diseases. Compared to the more popular physiochemical synthesis, the plant-derived combination of metallic nanoparticles using plant secondary metabolites as a precursor has a number of benefits, including low expenses, low energy consumption, biocompatibility, and medicinal usefulness. This study intends to explore the impacts of using plant-derived synthetic materials including metallic nanoparticles (NPs), emphasizing the benefits of their broad use in next-generation treatments for cancer, diabetes, Alzheimer's, and vector diseases. This comprehensive analysis investigates the potential of plant-derived remedies for diseases and looks at cutting-edge nanoformulation techniques aimed at addressing the function of the nanoparticles that accompany these organic substances. The purpose of the current review is to determine how plant extracts contribute to the synthesis of Silver nanoparticles (AgNPs), Gold nanoparticles (GtNPs), and platinum nanoparticles (PtNPs). It provides an overview of the many phytocompounds and their functions in biomedicine, including antibacterial, antioxidant, anticancer, and anti-inflammatory properties. Furthermore, this study placed a special focus on a range of applications, including drug delivery systems, diagnostics and therapy, the present benefits of nanoparticles (NPs), their biomedical uses in medical technology, and their toxicities.

Secretion of functional interferon by the type 3 secretion system of enteropathogenic Escherichia coli

BACKGROUND

Type I interferons (IFN-I)-a group of cytokines with immunomodulatory, antiproliferative, and antiviral properties-are widely used as therapeutics for various cancers and viral diseases. Since IFNs are proteins, they are highly susceptible to degradation by proteases and by hydrolysis in the strong acid environment of the stomach, and they are therefore administered parenterally. In this study, we examined whether the intestinal bacterium, enteropathogenic Escherichia coli (EPEC), can be exploited for oral delivery of IFN-Is. EPEC survives the harsh conditions of the stomach and, upon reaching the small intestine, expresses a type III secretion system (T3SS) that is used to translocate effector proteins across the bacterial envelope into the eukaryotic host cells.

RESULTS

In this study, we developed an attenuated EPEC strain that cannot colonize the host but can secrete functional human IFNα2 variant through the T3SS. We found that this bacteria-secreted IFN exhibited antiproliferative and antiviral activities similar to commercially available IFN.

CONCLUSION

These findings present a potential novel approach for the oral delivery of IFN via secreting bacteria.

Therapeutic Potential of Nanocarrier Mediated Delivery of Peptides for Wound Healing: Current Status, Challenges and Future Prospective

Wound healing presents a complex physiological process that involves a sequence of events orchestrated by various cellular and molecular mechanisms. In recent years, there has been growing interest in leveraging nanomaterials and peptides to enhance wound healing outcomes. Nanocarriers offer unique properties such as high surface area-to-volume ratio, tunable physicochemical characteristics, and the ability to deliver therapeutic agents in a controlled manner. Similarly, peptides, with their diverse biological activities and low immunogenicity, hold great promise as therapeutics in wound healing applications. In this review, authors explore the potential of peptides as bioactive components in wound healing formulations, focusing on their antimicrobial, anti-inflammatory, and pro-regenerative properties. Despite the significant progress made in this field, several challenges remain, including the need for standardized characterization methods, optimization of biocompatibility and safety profiles, and translation from bench to bedside. Furthermore, developing multifunctional nanomaterial-peptide hybrid systems represents promising avenues for future research. Overall, the integration of nanomaterials made up of natural or synthetic polymers with peptide-based formulations holds tremendous therapeutic potential in advancing the field of wound healing and improving clinical outcomes for patients with acute and chronic wounds.

Advancing Gastrointestinal Health: Curcumin's Efficacy and Nanopreparations

Curcumin (CCM) is a polyphenol compound extracted from the turmeric rhizome. It has various biological activities, including antibacterial, anti-inflammatory, anti-cancer, and antioxidant. Due to its diverse activities, it is often used by researchers to study the therapeutic effects on various diseases. However, its poor solubility leads to poor bioavailability, and it is necessary to increase the water solubility with the help of carriers to improve the therapeutic effect. Gastrointestinal disease is a major global health problem that continues to affect human health. In this review, we have summarized the possible mechanism and therapeutic effect of CCM in various gastrointestinal diseases, and the improvement in the curative effect of CCM with nanopreparation. Finally, we concluded that there have been many clinical trials of CCM in combination with other drugs for the treatment of gastrointestinal disease, but so far, few have used CCM nanomaterials for treatment. Although in vitro and preclinical experiments have shown that nanopreparations can improve the efficacy of CCM, there are still insufficient studies on the safety of carriers.

Waste-derived carbon nanostructures (WD-CNs): An innovative step toward waste to treasury

With the growing population, the accumulation of waste materials (WMs) (industrial/household waste) in the environment incessantly increases, affecting human health. Additionally, it affects the climate and ecosystem of terrestrial and water habitats, thereby needing effective management technology to control environmental pollution. In this aspect, managing these WMs to develop products that mitigate the associated issues is necessary. Researchers continue to focus on WMs management by adopting a circular economy. These WMs convert into useful/value-added products such as polymers and nanomaterials (NMs), especially carbon nanomaterials (CNs). The conversion/transformation of waste material into useful products is one of the best solutions for managing waste. Waste-derived CNs (WD-CNs) have established boundless promises for numerous applications like environmental remediation, energy, catalysts, sensors, and biomedical applications. This review paper discusses the several sources of waste material (agricultural, plastic, industrial, biomass, and other) transforming into WD-CNs, such as carbon nanotubes (CNTs), biochar, graphene, carbon nanofibers (CNFs), carbon dots, etc., are extensively elaborated and their application. The impact of metal doping within the WD-CNs is briefly discussed, along with their applicability to end applications.

Chitosan functionalized doxorubicin loaded poly(methacrylamide) based copolymeric nanoparticles for enhanced cellular internalization and in vitro anticancer evaluation

Doxorubicin (Dox), a chemotherapeutic agent, encounters challenges such as a short half-life, dose-dependent toxicity, and low solubility. In this context, the present study involved the fabrication of N-(2-hydroxypropyl)methacrylamide (HPMA) and N-(3-aminopropyl)methacrylamide (APMA) bearing P(HPMA-s-APMA) copolymeric nanoparticles (P(HPMA-s-APMA) NPs) and their investigation for efficient delivery of Dox. Furthermore, the synthesized nanoparticles (NPs) were coated with chitosan (Cht) to generate positively charged nanoformulations. The prepared formulations were evaluated for particle size, morphology, surface charge analysis, percentage encapsulation efficiency (EE%), and drug release studies. The anticancer activity of Cht-P(HPMA-s-APMA)-Dox NPs was assessed in the HeLa cancer cell line. The prepared P(HPMA-s-APMA)-Dox NPs exhibited an average particle size of 240-250 nm. Chitosan decorated P(HPMA-s-APMA)-Dox NPs displayed a significant increase in particle size, and the zeta potential shifted from negative to positive. The EE% for Cht-P(HPMA-s-APMA)-Dox NPs was calculated to be 68.06 %. The drug release studies revealed a rapid release of drug from Cht-P(HPMA-s-APMA)-Dox NPs at pH 4.8 than pH 7.4, demonstrating the pH-responsiveness of nanoformulation. Furthermore, the cell viability assay and internalization studies revealed that Cht-P(HPMA-s-APMA)-Dox NPs had a high cytotoxic response and significant cellular uptake. Hence, the Cht-P(HPMA-s-APMA)-Dox NPs appeared to be a suitable nanocarrier for effective, and safe chemotherapy.

Gastroprotective Chitosan Nanoparticles Loaded with Oleuropein: An In Vivo Proof of Concept

Oleuropein is the main constituent of olive leaf extract, and it has shown antioxidant and gastroprotective properties against gastric ulcers. Chitosan nanoparticles are known for their mucoadhesive abilities, and consequently, they can increase the retention time of drugs in the gastrointestinal tract. Therefore, loading oleuropein onto chitosan nanoparticles is expected to enhance its biological efficiency. Oleuropein-loaded chitosan nanoparticles were prepared and characterized for particle size, surface charge, in vitro release, and anti-inflammatory activity. Their in vivo efficacy was assessed by measuring specific inflammatory and protective biomarkers, along with histopathological examination. The optimum oleuropein chitosan nanoparticles were cationic, had a size of 174.3 ± 2.4 nm and an entrapment efficiency of 92.81%, and released 70% of oleuropein within 8 h. They recorded a lower IC50 in comparison to oleuropein solutions for membrane stabilization of RBCs (22.6 vs. 25.6 µg/mL) and lipoxygenase inhibition (7.17 vs. 15.6 µg/mL). In an ethanol-induced gastric ulcer in vivo model, they decreased IL-1β, TNF-α, and TBARS levels by 2.1, 1.7, and 1.3 fold, respectively, in comparison to increments caused by exposure to ethanol. Moreover, they increased prostaglandin E2 and catalase enzyme levels by 2.4 and 3.8 fold, respectively. Immunohistochemical examination showed that oleuropein chitosan nanoparticles markedly lowered the expression of IL-6 and caspase-3 in gastric tissues in comparison to oleuropein solution. Overall, oleuropein chitosan nanoparticles showed superior gastroprotective effects to oleuropein solution since comparable effects were demonstrated at a 12-fold lower drug dose, delineating that chitosan nanoparticles indeed enhanced the potency of oleuropein as a gastroprotective agent.

Reviewing particulate delivery systems loaded with repurposed tetracyclines - From micro to nanoparticles

Tetracyclines (TCs) are a class of broad-spectrum antibacterial agents recognized for their multifaceted properties, including anti-inflammatory, angiogenic and osteogenic effects. This versatility positions them as suitable candidates for drug repurposing, benefitting from well-characterized safety and pharmacological profiles. In the attempt to explore both their antibacterial and pleiotropic effects locally, innovative therapeutic strategies were set on engineering tetracycline-loaded micro and nanoparticles to tackle a vast number of clinical applications. Moreover, the conjoined drug carrier can function as an active component of the therapeutic approach, reducing off-target effects and accumulation, synergizing to an improvement of the therapeutic efficacy. In this comprehensive review we will critically evaluate recent advances involving the use of tetracyclines loaded onto micro- or nanoparticles, intended for biomedical applications, and discuss emerging approaches and current limitations associated with these drug carriers. Owing to their distinctive physical, chemical, and biological properties, these novel carriers have the potential to become a platform technology in personalized regenerative medicine and other therapeutic applications.

Oral Absorption of Middle-to-Large Molecules and Its Improvement, with a Focus on New Modality Drugs

To meet unmet medical needs, middle-to-large molecules, including peptides and oligonucleotides, have emerged as new therapeutic modalities. Owing to their middle-to-large molecular sizes, middle-to-large molecules are not suitable for oral absorption, but there are high expectations around orally bioavailable macromolecular drugs, since oral administration is the most convenient dosing route. Therefore, extensive efforts have been made to create bioavailable middle-to-large molecules or develop absorption enhancement technology, from which some successes have recently been reported. For example, Rybelsus® tablets and Mycapssa® capsules, both of which contain absorption enhancers, were approved as oral medications for type 2 diabetes and acromegaly, respectively. The oral administration of Rybelsus and Mycapssa exposes their pharmacologically active peptides with molecular weights greater than 1000, namely, semaglutide and octreotide, respectively, into systemic circulation. Although these two medications represent major achievements in the development of orally absorbable peptide formulations, the oral bioavailability of peptides after taking Rybelsus and Mycapssa is still only around 1%. In this article, we review the approaches and recent advances of orally bioavailable middle-to-large molecules and discuss challenges for improving their oral absorption.

Trimethylated chitosan-coated flexible liposomes with resveratrol for topical drug delivery to reduce blue-light-induced retinal damage

LED-related blue-light-induced damage can cause eye diseases. However, drug delivery in patients with ocular diseases is faced with various challenges. In this study, we developed flexible liposomes based on trimethylated chitosan (TMC-Lipo) to deliver resveratrol for the treatment of retinal diseases. Flexible liposomes can easily cross various biological barriers. Chitosan and its derivatives have adhesive properties and are widely used in mucoadhesive drug delivery systems. Therefore, we wrapped flexible liposomes with trimethylated chitosan via electrostatic adsorption. The charge of the flexible liposomes became positive after encapsulation in TMC, and they remained stable in artificial tears. We assessed the safety of TMC-Lipo in cellular and zebrafish experiments and found that it can be safely used. In addition, treatment with TMC-Lipo significantly reduced H2O2-induced damage to ARPE-19 cells, restored mitochondrial membrane potential, and protected the cells. TMC-Lipo more easily reached the posterior ocular segment of the mice than liposome nanoparticles and attenuated blue-light-induced retinal cytopathy. Our study demonstrates that effective eye drop formulations can be developed based on trimethylated chitosan, which provides a promising approach for the treatment of ocular diseases.

Protective immunization against Enterohemorrhagic Escherichia coli and Shigella dysenteriae Type 1 by chitosan nanoparticle loaded with recombinant chimeric antigens comprising EIT and STX1B-IpaD

Increasing evidence demonstrated that Enterohemorrhagic Escherichia coli (EHEC) and Shigella dysenteriae type 1 (S. dysenteriae1) are considered pathogens, that are connected with diarrhea and are still the greatest cause of death in children under the age of five years, worldwide. EHEC and S. dysenteriae 1 infections can be prevented and managed using a vaccination strategy against pathogen attachment stages. In this study, the chitosan nanostructures were loaded with recombinant EIT and STX1B-IpaD polypeptides. The immunogenic properties of this nano-vaccine candidate were investigated. The EIT and STX1B-IpaD recombinant proteins were heterologous expressed, purified, and confirmed by western blotting. The chitosan nanoparticles, were used to encapsulate the purified proteins. The immunogenicity of recombinant nano vaccine candidate, was examined in three groups of BalB/c mice by injection, oral delivery, and combination of oral-injection. ELISA and antibody titer, evaluated the humoral immune response. Finally, all three mice groups were challenged by two pathogens to test the ability of the nano-vaccine candidate to protect against bacterial infection. The Sereny test in guinea pigs was used to confirm the neutralizing effect of immune sera in controlling S. dysenteriae 1, infections. SDS-PAGE and western blotting, confirmed the presence and specificity of 63 and 27 kDa recombinant EIT and STX1B-IpaD, respectively. The results show that the nanoparticles containing recombinant proteins could stimulate the systemic and mucosal immune systems by producing IgG and IgA, respectively. The challenge test showed that, the candidate nano-vaccine could protect the animal model from bacterial infection. The combination of multiple recombinant proteins, carrying several epitopes and natural nanoparticles could evocate remarkable humoral and mucosal responses and improve the protection properties of synthetic antigens. Furthermore, compared with other available antigen delivery methods, using oral delivery as immune priming and injection as a booster method, could act as combinatorial methods to achieve a higher level of immunity. This approach could present an appropriate vaccine candidate against both EHEC and S. dysenteriae 1.

Temperature-Sensitive Nanocarbon Hydrogel for Photothermal Therapy of Tumors

Background

Intelligent hydrogels continue to encounter formidable obstacles in the field of cancer treatment. A wide variety of hydrogel materials have been designed for diverse purposes, but materials with satisfactory therapeutic effects are still urgently needed.

Methods

Here, we prepared an injectable hydrogel by means of physical crosslinking. Carbon nanoparticle suspension injection (CNSI), a sentinel lymph node imaging agent that has been widely used in the clinic, with sodium β-glycerophosphate (β-GP) were added to a temperature-sensitive chitosan (CS) hydrogel (CS/GP@CN) as an agent for photothermal therapy (PTT). After evaluating the rheological, morphological, and structural properties of the hydrogel, we used 4T1 mouse breast cancer cells and B16 melanoma cells to assess its in vitro properties. Then, we intratumorally injected the hydrogel into BALB/c tumor-bearing mice to assess the in vivo PTT effect, antitumor immune response and the number of lung metastases.

Results

Surprisingly, this nanocarbon hydrogel called CS/GP@CN hydrogel not only had good biocompatibility and a great PTT effect under 808nm laser irradiation but also facilitated the maturation of dendritic cells to stimulate the antitumor immune response and had an extraordinary antimetastatic effect in the lungs.

Discussion

Overall, this innovative temperature-sensitive nanocarbon hydrogel, which exists in a liquid state at room temperature and transforms to a gel at 37 °C, is an outstanding local delivery platform with tremendous PTT potential and broad clinical application prospects.

Polysaccharide-Based Nanogels to Overcome Mucus, Skin, Cornea, and Blood-Brain Barriers: A Review

Nanocarriers have been extensively developed in the biomedical field to enhance the treatment of various diseases. However, to effectively deliver therapeutic agents to desired target tissues and enhance their pharmacological activity, these nanocarriers must overcome biological barriers, such as mucus gel, skin, cornea, and blood-brain barriers. Polysaccharides possess qualities such as excellent biocompatibility, biodegradability, unique biological properties, and good accessibility, making them ideal materials for constructing drug delivery carriers. Nanogels, as a novel drug delivery platform, consist of three-dimensional polymer networks at the nanoscale, offering a promising strategy for encapsulating different pharmaceutical agents, prolonging retention time, and enhancing penetration. These attractive properties offer great potential for the utilization of polysaccharide-based nanogels as drug delivery systems to overcome biological barriers. Hence, this review discusses the properties of various barriers and the associated constraints, followed by summarizing the most recent development of polysaccharide-based nanogels in drug delivery to overcome biological barriers. It is expected to provide inspiration and motivation for better design and development of polysaccharide-based drug delivery systems to enhance bioavailability and efficacy while minimizing side effects.

Advances in Natural Polymer-Based Transdermal Drug Delivery Systems for Tumor Therapy

As an alternative to traditional oral and intravenous injections with limited efficacy, transdermal drug delivery (TDD) has shown great promise in tumor treatment. Over the past decade, natural polymers have been designed into various nanocarriers due to their excellent biocompatibility, biodegradability, and easy availability, providing more options for TDD. In addition, surface functionalization modification of the rich functional groups of natural polymers, which in turn are developed into targeted and stimulus-responsive functional materials, allows precise delivery of drugs to tumor sites and release of drugs in response to specific stimuli. It not only improves the treatment efficiency of tumor but also reduces the toxic and side effects to normal tissues. Therefore, the development of natural polymer-based TDD (NPTDD) systems has great potential in tumor therapy. In this review, the mechanism of NPTDD systems such as penetration enhancers, nanoparticles, microneedles, hydrogels and nanofibers prepared from hyaluronic acid, chitosan, sodium alginate, cellulose, heparin and protein, and their applications in tumor therapy are overviewed. This review also outlines the future prospects and current challenges of NPTDD systems for local treatment tumors.

An updated review on oral protein-based antigen vaccines efficiency and delivery approaches: a special attention to infectious diseases

Various infectious agents affect human health via the oral entrance. The majority of pathogens lack approved vaccines. Oral vaccination is a convenient, safe and cost-effective approach with the potential of provoking mucosal and systemic immunity and maintaining individual satisfaction. However, vaccines should overcome the intricate environment of the gastrointestinal tract (GIT). Oral protein-based antigen vaccines (OPAVs) are easier to administer than injectable vaccines and do not require trained healthcare professionals. Additionally, the risk of needle-related injuries, pain, and discomfort is eliminated. However, OPAVs stability at environmental and GIT conditions should be considered to enhance their stability and facilitate their transport and storage. These vaccines elicit the local immunity, protecting GIT, genital tract and respiratory epithelial surfaces, where numerous pathogens penetrate the body. OPAVs can also be manipulated (such as using specific incorporated ligand and receptors) to elicit targeted immune response. However, low bioavailability of OPAVs necessitates development of proper protein carriers and formulations to enhance their stability and efficacy. There are several strategies to improve their efficacy or protective effects, such as incorporation of adjuvants, enzyme inhibitors, mucoadhesive or penetrating devices and permeation enhancers. Hence, efficient delivery of OPAVs into GIT require proper delivery systems mainly including smart target systems, probiotics, muco-adhesive carriers, lipid- and plant-based delivery systems and nano- and microparticles.

Chitosan-Based Nano Systems for Natural Antioxidants in Breast Cancer Therapy

Breast cancer is a major cause of death globally, accounting for around 13% of all deaths. Chemotherapy, the common treatment for cancer, can have side effects that lead to the production of reactive oxygen species (ROS) and an increase in oxidative stress in the body. Antioxidants are important for maintaining the health of cells and helping the immune system function properly. They play a crucial role in balancing the body's internal environment. Using natural antioxidants is an alternative to mitigate the harmful effects of oxidative stress. However, around 80% of natural antioxidants have limited effectiveness when taken orally because they do not dissolve well in water or other solvents. This poor solubility affects their ability to be absorbed by the body and limits their bioavailability. One strategy that has been considered is to increase their water solubility to increase their oral bioavailability. Chitosan-based nanoparticle (CSNP) systems have been extensively explored due to their reliability and simpler synthesis routes. This review focuses on the various methods of chitosan-based nanoformulation for developing effective oral dosage forms for natural antioxidants based on the pharmacokinetics and pharmacodynamics properties. Chitosan (CS) could be a model, because of its wide use in polymeric NPs research, thus providing a better understanding of the role of vehicles that carry natural antioxidants in maintaining the stability and enhancing the performance of cancer drugs.

Chitosan Hydrogel-Delivered ABE8e Corrects PAX9 Mutant in Dental Pulp Stem Cells

Hypodontia (dental agenesis) is a genetic disorder, and it has been identified that the mutation C175T in PAX9 could lead to hypodontia. Cas9 nickase (nCas9)-mediated homology-directed repair (HDR) and base editing were used for the correction of this mutated point. This study aimed to investigate the effect of HDR and the base editor ABE8e in editing PAX9 mutant. It was found that the chitosan hydrogel was efficient in delivering naked DNA into dental pulp stem cells (DPSCs). To explore the influence of the C175T mutation in PAX9 on the proliferation of DPSCs, hydrogel was employed to deliver PAX9 mutant vector into DPSCs, finding that the PAX9-containing C175T mutation failed to promote the proliferation of DPSCs. Firstly, DPSCs stably carrying PAX9 mutant were constructed. Either an HDR or ABE8e system was delivered into the above-mentioned stable DPSCs, and then the correction efficiency using Sanger sequencing and Western blotting was determined. Meanwhile, the ABE8e presented significantly higher efficiency in correcting C175T compared with HDR. Furthermore, the corrected PAX9 presented enhanced viability and differentiation capacity for osteogenic and neurogenic lineages; the corrected PAX9 even possessed extremely enhanced transcriptional activation ability. In summary, this study has powerful implications for studies into base editors, chitosan hydrogel, and DPSCs in treating hypodontia.

Chitosan and chito-oligosaccharide: a versatile biopolymer with endless grafting possibilities for multifarious applications

Chito-oligosaccharides (COS), derived from chitosan (CH), are attracting increasing attention as drug delivery carriers due to their biocompatibility, biodegradability, and mucoadhesive properties. Grafting, the process of chemically modifying CH/COS by adding side chains, has been used to improve their drug delivery performance by enhancing their stability, targeted delivery, and controlled release. In this review, we aim to provide an in-depth study on the recent advances in the grafting of CH/COS for multifarious applications. Moreover, the various strategies and techniques used for grafting, including chemical modification, enzymatic modification, and physical modification, are elaborated. The properties of grafted CH/COS, such as stability, solubility, and biocompatibility, were reported. Additionally, the review detailed the various applications of grafted CH/COS in drug delivery, including the delivery of small drug molecule, proteins, and RNA interference therapeutics. Furthermore, the effectiveness of grafted CH/COS in improving the pharmacokinetics and pharmacodynamics of drugs was included. Finally, the challenges and limitations associated with the use of grafted CH/COS for drug delivery and outline directions for future research are addressed. The insights provided in this review will be valuable for researchers and drug development professionals interested in the application of grafted CH/COS for multifarious applications.

Eco-friendly deacetylated chitosan base siRNA biological-nanopesticide loading cyromazine for efficiently controlling Spodoptera frugiperda

Spodoptera frugiperda is a serious threat to various crops, such as corn and rice, and results in severe economic losses. Herein, a chitin synthase sfCHS highly expressed in the epidermis of S. frugiperda was screened, and when interfered by an sfCHS-siRNA nanocomplex, most individuals could not ecdysis (mortality rate 53.3 %) or pupate (abnormal pupation 80.6 %). Based on the results of structure-based virtual screening, cyromazine (CYR, binding free energy -57.285 kcal/mol) could inhibit ecdysis (LC₅₀, 19.599 μg/g). CYR-CS/siRNA nanoparticles encapsulating CYR and SfCHS-siRNA with chitosan (CS) were successfully prepared, as confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and 74.9 mg/g CYR was characterized in the core of CYR-CS/siRNA by high-performance liquid chromatography and Fourier transform infrared spectroscopy. Small amounts of prepared CYR-CS/siRNA containing only 1.5 μg/g CYR could better inhibit chitin synthesis in the cuticle and peritrophic membrane (mortality rate 84.4 %). Therefore, chitosan/siRNA nanoparticle-loaded pesticides were useful for pesticide reduction and comprehensive control of S. frugiperda.

A dsRNA delivery system based on the rosin-modified polyethylene glycol and chitosan induces gene silencing and mortality in Nilaparvata lugens

BACKGROUND

RNA interference (RNAi) technology has been considered as a promising pest control strategy due to its species selectivity. One of the popular RNAs is exogenous double strand RNA (dsRNA). However, dsRNA is easily degraded by nucleases and is difficult to pass through the insect body walls, and these factors restrict the application of RNAi technology in pest management. Here, the brown planthopper (BPH, Nilaparvata lugens), a major hemipteran pest of rice in Asia countries was used as a model insect, and a dsRNA topical delivery system was constructed.

RESULTS

The carrier part of the delivery system was composed of rosin-modified polyethylene glycol and chitosan, termed ROPE@C. When the N/P ratio was greater than 1:1.25, the dsRNA/ROPE@C complex encouraged full binding of the dsRNA. The gel electrophoresis results showed that ROPE@C improved the stability of dsRNA in the presence of nucleases in gut and lumen contents for at least 6 h and in the temperature range from 4 °C to 37 °C. The dsNlCHSA/ROPE@C/alkyl polyglycoside (APG) nano-formulation directly penetrated the body walls reaching hemocoel within 6 h, and consequently, the relative expression of chitin synthetase A (CHSA) in BPH was reduced by 54.3% and the mortality rate was 65.8%.

CONCLUSION

We developed an appropriate delivery method for dsRNA application in BPH, which is helpful for a large-scale application of RNAi pesticides. © 2022 Society of Chemical Industry.

How wound environments trigger the release from Rifampicin-loaded liposomes

BACKGROUND

Chronic wounds often contain high levels of proinflammatory cytokines that prolong the wound-healing process. Patients suffering from these conditions are likely to benefit from topical rifampicin therapy. Although recent research indicates considerable anti-inflammatory properties of the antibiotic, currently, there are no commercial topical wound healing products available. To address this medical need, a liposomal drug delivery system was developed. A mechanistic investigation outlined major influences of wound environments that affect the release kinetics and, as a consequence, local bioavailability.

METHODS

Liposomes were prepared using the thin-film hydration method and subsequently freeze-dried at the pilot scale to improve their stability. We investigated the influence of oxidation, plasma proteins, and lipolysis on the in vitro release of rifampicin and its two main degradation products using the Dispersion Releaser technology. A novel simulated wound fluid provided a standardized environment to study critical influences on the release. It reflects the pathophysiological environment regarding pH, buffer capacity, and protein content.

RESULTS

During storage, the liposomes efficiently protect rifampicin from degradation. After the dispersion of the vesicles in simulated wound fluid, despite the significant albumin binding (>70%), proteins have no considerable effect on the release. Also, the presence of lipase at pathophysiologically elevated concentrations did not trigger the liberation of rifampicin. Surprisingly, the oxidative environment of the wound bed represents the strongest accelerating influence and triggers the release.

CONCLUSION

A stable topical delivery system of rifampicin has been developed. Once the formulation comes in contact with simulated wound fluid, drug oxidation accelerates the release. The influence of lipases that are assumed to trigger the liberation from liposomes depends on the drug-to-lipid ratio. Considering that inflamed tissues exhibit elevated levels of oxidative stress, the trigger mechanism identified for rifampicin contributes to targeted drug delivery.

Drug Delivery Systems in Regenerative Medicine: An Updated Review

Modern drug discovery methods led to evolving new agents with significant therapeutic potential. However, their properties, such as solubility and administration-related challenges, may hinder their benefits. Moreover, advances in biotechnology resulted in the development of a new generation of molecules with a short half-life that necessitates frequent administration. In this context, controlled release systems are required to enhance treatment efficacy and improve patient compliance. Innovative drug delivery systems are promising tools that protect therapeutic proteins and peptides against proteolytic degradation where controlled delivery is achievable. The present review provides an overview of different approaches used for drug delivery.

Coating Materials to Increase the Stability of Liposomes

Liposomes carry various compounds with applications in pharmaceutical, food, and cosmetic fields, and the administration route is especially parenteral, oral, or transdermal. Liposomes are used to preserve and release the internal components, thus maintaining the properties of the compounds, the stability and shelf life of the encapsulated products, and their functional benefits. The main problem in obtaining liposomes at the industrial level is their low stability due to fragile phospholipid membranes. To increase the stability of liposomes, phospholipid bilayers have been modified or different coating materials have been developed and studied, both for liposomes with applications in the pharmaceutical field and liposomes in the food field. In the cosmetic field, liposomes need no additional coating because the liposomal formulation is intended to have a fast penetration into the skin. The aim of this review is to provide current knowledge regarding physical and chemical factors that influence stability, coating materials for liposomes with applications in the pharmaceutical and food fields to increase the stability of liposomes containing various sensitive compounds, and absorption of the liposomes and commercial liposomal products obtained through various technologies available on the market.

Chitosan-Based Nanoparticles with Optimized Parameters for Targeted Delivery of a Specific Anticancer Drug-A Comprehensive Review

Chitosan is a positively charged polysaccharide obtained through chitin deacetylation. It belongs to a group of biodegradable, bioavailable, and non-toxic materials of natural origin; thus, it is a promising matrix for creating delivery systems of different active agents. Recently, much attention has been paid to nanodelivery systems as carriers to enable better bioavailability, and thus higher efficiency of the loaded drug. The present review is focused on the progress in chitosan-based nanoparticles for the targeted delivery of antitumor drugs. The paper discusses literature reports from the last three years in which chitosan nanoparticles were applied as carriers for active substances used in antitumor therapy and potential new drugs with anticancer properties. Special attention was paid to the different treatments applied to increase the therapeutic effectiveness and minimize the side effects of a specific active substance.

Pharmaceutical Development of Nanostructured Vesicular Hydrogel Formulations of Rifampicin for Wound Healing

Chronic wounds exhibit elevated levels of inflammatory cytokines, resulting in the release of proteolytic enzymes which delay wound-healing processes. In recent years, rifampicin has gained significant attention in the treatment of chronic wounds due to an interesting combination of antibacterial and anti-inflammatory effects. Unfortunately, rifampicin is sensitive to hydrolysis and oxidation. As a result, no topical drug product for wound-healing applications has been approved. To address this medical need two nanostructured hydrogel formulations of rifampicin were developed. The liposomal vesicles were embedded into hydroxypropyl methylcellulose (HPMC) gel or a combination of hyaluronic acid and marine collagen. To protect rifampicin from degradation in aqueous environments, a freeze-drying method was developed. Before freeze-drying, two well-defined hydrogel preparations were obtained. After freeze-drying, the visual appearance, chemical stability, residual moisture content, and redispersion time of both preparations were within acceptable limits. However, the morphological characterization revealed an increase in the vesicle size for collagen-hyaluronic acid hydrogel. This was confirmed by subsequent release studies. Interactions of marine collagen with phosphatidylcholine were held responsible for this effect. The HPMC hydrogel formulation remained stable over 6 months of storage. Moving forward, this product fulfills all criteria to be evaluated in preclinical and clinical studies.

Single -and Multi-Walled Carbon Nanotubes as Nanocarriers for the Delivery of 7-Hydroxyflavone

The research on flavonoids has exponentially grown since their first therapeutic evidence, in 1937. They are effective in vitro in a wide range of human diseases, particularly those mediated by free radicals, such as cancer, atherosclerosis, AIDS, or neuronal diseases. However, their applications have been reduced due to their low solubility, poor absorption, and rapid metabolism. Flavonoid encapsulation in nanocarriers significantly improves their oral absorption, protects the drug against degradation, decreases the first-pass hepatic effect, and makes absorption through the lymphatic system easier. In this work, carbon nanotubes were used as nanocarriers of 7-hydroxyflavone, 7-HF. The encapsulation of 7-HF into pristine single- and multi-walled carbon nanotubes, and into -COOH functionalized single-walled carbon nanotubes has been investigated. The equilibrium association constants were estimated. The structural backbone of 7-HF, two benzene rings linked through three carbon atoms that form a pyran heterocyclic ring containing a keto group, seems to play a key role in the 7-HF/CNT interactions, although other types of interactions are also at work. The in vitro release of 7-HF was studied at three pHs, 2.0, 7.4, and 9.2, mimicking the different biological barriers of the human organism.

Biopolymeric nanocarrier: an auspicious system for oral delivery of insulin

Subcutaneous administration of insulin has been practiced for the clinical supervision of diabetes pathogenesis but it is often ineffective to imitate the glucose homeostasis and is always invasive. Therefore, it causes patient discomfort and infection of local tissue. These issues lead to finding an alternative route for insulin delivery that could be effective, promising, and non-invasive. However, delivery of insulin orally is the most suitable route but the rapid breakdown of insulin by the gastrointestinal enzymes becomes a major barrier to this method. Therefore, nanocarriers (which guard insulin against degradation and facilitate its uptake) are preferred for oral insulin delivery. Among various categories of nanocarriers, bio-polymeric nanocarriers draw special attention owing to their hydrophilic, non-toxic, and biodegradable nature. This review provides a detailed overview of insulin-loaded biopolymer-based nanocarriers, which give future direction in the optimization and development of a clinically functional formulation for their effective and safe delivery.

Chitosan/Lactic Acid Systems: Liquid Crystalline Behavior, Rheological Properties, and Riboflavin Release In Vitro

Chitosan or its derivatives exhibit lyotropic liquid crystalline mesophases under certain conditions due to its semi-rigid structures. This work describes the development of chitosan-based biocompatible systems that include new components: lactic acid and non-ionic surfactants. Polarized optical microscopy studies revealed that these systems are capable of forming gels or lyotropic liquid crystals (LLCs) in a certain range of chitosan and lactic acid concentrations. According to the viscosity studies, the rheological flow of the LLCs can be accurately described by the Casson flow model. The intermolecular interactions of the LLC components were studied by FTIR spectroscopy. According to the FTIR data, hydrogen bonding is supposed to be responsible for the formation of the LLCs. In the studied systems, this LLC complex exists as the [ChitH+·CH3-CH(OH)-COO-] ion pair. The studied gel and LLCs were shown to possess the most prolonged release capabilities for riboflavin among similar binary LLC systems. The supramolecular organization and rheological characteristics of the studied chitosan-based systems were found to affect the release of riboflavin.

Chitosan-based delivery system enhances antimicrobial activity of chlorhexidine

Infected chronic skin wounds and other skin infections are increasingly putting pressure on the health care providers and patients. The pressure is especially concerning due to the rise of antimicrobial resistance and biofilm-producing bacteria that further impair treatment success. Therefore, innovative strategies for wound healing and bacterial eradication are urgently needed; utilization of materials with inherent biological properties could offer a potential solution. Chitosan is one of the most frequently used polymers in delivery systems. This bioactive polymer is often regarded as an attractive constituent in delivery systems due to its inherent antimicrobial, anti-inflammatory, anti-oxidative, and wound healing properties. However, lipid-based vesicles and liposomes are generally considered more suitable as delivery systems for skin due to their ability to interact with the skin structure and provide prolonged release, protect the antimicrobial compound, and allow high local concentrations at the infected site. To take advantage of the beneficial attributes of the lipid-based vesicles and chitosan, these components can be combined into chitosan-containing liposomes or chitosomes and chitosan-coated liposomes. These systems have previously been investigated for use in wound therapy; however, their potential in infected wounds is not fully investigated. In this study, we aimed to investigate whether both the chitosan-containing and chitosan-coated liposomes tailored for infected wounds could improve the antimicrobial activity of the membrane-active antimicrobial chlorhexidine, while assuring both the anti-inflammatory activity and cell compatibility. Chlorhexidine was incorporated into three different vesicles, namely plain (chitosan-free), chitosan-containing and chitosan-coated liposomes that were optimized for skin wounds. Their release profile, antimicrobial activities, anti-inflammatory properties, and cell compatibility were assessed in vitro. The vesicles comprising chitosan demonstrated slower release rate of chlorhexidine and high cell compatibility. Additionally, the inflammatory responses in murine macrophages treated with these vesicles were reduced by about 60% compared to non-treated cells. Finally, liposomes containing both chitosan and chlorhexidine demonstrated the strongest antibacterial effect against Staphylococcus aureus. Both chitosan-containing and chitosan-coated liposomes comprising chlorhexidine could serve as excellent platforms for the delivery of membrane-active antimicrobials to infected wounds as confirmed by improved antimicrobial performance of chlorhexidine.

Obtaining and Characterizing Composite Biomaterials of Animal Resources with Potential Applications in Regenerative Medicine

Raw materials, such as collagen and chitosan, obtained from by-products from the food industry (beef hides and crustacean exoskeletons), can be used to obtain collagen–chitosan composite biomaterials, with potential applications in regenerative medicine. Functionalization of these composite biomaterials is a possibility, thus, resulting in a molecule with potential applications in regenerative medicine, namely clotrimazole (a molecule with antibacterial, antifungal, and antitumor activity), at a mass ratio (collagen–chitosan–clotrimazole) of 1:1:0.1. This functionalized composite biomaterial has great potential for application in regenerative medicine, due to the following properties: (1) it is porous, and the pores formed are interconnected, due to the use of a mass ratio between collagen and chitosan of 1:1; (2) the size of the formed pores is between 500–50 μm; (3) between collagen and chitosan, hydrogen bonds are formed, which ensure the unity of composite biomaterial; (4) the functionalized bio-composite exhibits in vitro antimicrobial activity for Candida albicans, Staphylococcus aureus, and Staphylococcus aureus MRSA; for the latter microorganism, the antimicrobial activity is equivalent to that of the antibiotic Minocycline; (5) the proliferation tests performed on a standardized line of normal human cells with simple or composite materials obtained by lyophilization do not show cytotoxicity in the concentration range studied (10–500) μg/mL.

Production of Low Molecular Weight Chitosan Using a Combination of Weak Acid and Ultrasonication Methods

Low molecular weight chitosan (LMWC) has higher solubility and lower viscosity allowing for a wider pharmaceutical application compared to high molecular weight chitosan. LMWC chitosan can be obtained through a chitosan depolymerization process. This research aimed to produce LWMC using the combination of formic acid and ultrasonication method with the optimal condition of the depolymerization process. The chitosan depolymerization method was performed by combining formic acid and ultrasonication. The optimum conditions of the depolymerization process were obtained using the Box–Behnken design. The LMWC obtained from depolymerization was characterized to identify its yield, degree of deacetylation, the molecular weight, structure, morphology, thermal behavior, and crystallinity index. Results: The characterization results of LWMC obtained from the depolymerization process using the optimum conditions showed that the yield was 89.398%; the degree of deacetylation was 98.076%; the molecular weight was 32.814 kDa; there was no change in the chemical structure, LWMC had disorganized shape, there was no change in the thermal behavior, and LWMC had a more amorphous shape compared to native chitosan. Conclusion: The production of LWMC involving depolymerization in the presence of weak acid and ultrasonication can be developed by using the optimal condition of the depolymerization process.

Nanodelivery Systems Delivering Hypoxia-Inducible Factor-1 Alpha Short Interfering RNA and Antisense Oligonucleotide for Cancer Treatment

Hypoxia-inducible factor (HIF), which plays a crucial role in oxygen homeostasis, contributes to immunosuppression, tumor angiogenesis, multidrug resistance, photodynamic therapy resistance, and metastasis. HIF as a therapeutic target has attracted scientists’ strong academic research interests. Short interfering RNA (siRNA) and antisense oligonucleotide (ASO) are the more promising and broadly utilized methods for oligonucleotide-based therapy. Their physicochemical characteristics such as hydrophilicity, negative charge, and high molecular weight make them impossible to cross the cell membrane. Moreover, siRNA and ASO are subjected to a rapid deterioration in circulation and cannot translocate into nuclear. Delivery of siRNA and ASO to specific gene targets should be realized without off-target gene silencing and affecting the healthy cells. Nanoparticles as vectors for delivery of siRNA and ASO possess great advantages and flourish in academic research. In this review, we summarized and analyzed regulation mechanisms of HIF under hypoxia, the significant role of HIF in promoting tumor progression, and recent academic research on nanoparticle-based delivery of HIF siRNA and ASO for cancer immunotherapy, antiangiogenesis, reversal of multidrug resistance and radioresistance, potentiating photodynamic therapy, inhibiting tumor metastasis and proliferation, and enhancing apoptosis are reviewed in this thesis. Furthermore, we hope to provide some rewarding suggestions and enlightenments for targeting HIF gene therapy.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

Application of Chitosan and Its Derivative Polymers in Clinical Medicine and Agriculture

Chitosan is a biodegradable natural polymer derived from the exoskeleton of crustaceans. Because of its biocompatibility and non-biotoxicity, chitosan is widely used in the fields of medicine and agriculture. With the latest technology and technological progress, different active functional groups can be connected by modification, surface modification, or other configurations with various physical, chemical, and biological properties. These changes can significantly expand the application range and efficacy of chitosan polymers. This paper reviews the different uses of chitosan, such as catheter bridging to repair nerve broken ends, making wound auxiliaries, as tissue engineering repair materials for bone or cartilage, or as carriers for a variety of drugs to expand the volume or slow-release and even show potential in the fight against COVID-19. In addition, it is also discussed that chitosan in agriculture can improve the growth of crops and can be used as an antioxidant coating because its natural antibacterial properties are used alone or in conjunction with a variety of endophytic bacteria and metal ions. Generally speaking, chitosan is a kind of polymer material with excellent development prospects in medicine and agriculture.