Synthesis, characterization, and in vitro cytotoxicity of fatty acyl-CGKRK-chitosan oligosaccharides conjugates for siRNA delivery

Design, Synthesis, and Evaluation of Oleyl-WRH Peptides for siRNA Delivery

Delivering nucleic acid therapeutics across cell membranes is a significant challenge. Cell-penetrating peptides (CPPs) containing arginine (R), tryptophan (W), and histidine (H) show promise for siRNA delivery. To improve siRNA delivery and silence a model STAT3 gene, we hypothesized that oleyl acylation to CPPs, specifically (WRH)n, would enhance STAT3 silencing efficiency in breast and ovarian cancer cells. Using Fmoc/tBu solid-phase peptide chemistry, we synthesized, purified, and characterized the oleyl-conjugated (WRH)n (n = 1-4) peptides. The peptide/siRNA complexes were non-cytotoxic at N/P 40 (~20 μM) against MDA-MB-231, MCF-7, SK-OV-3, and HEK-293 cells after 72 h incubation. All peptide/siRNA complexes showed serum stability at N/P ≥ 40. The synthesized conjugates, with a diameter of <100 nm, formed nano-complexes with siRNA and exhibited a stable range of zeta potential values (13-18 mV at N/P = 40). Confocal microscopy and flow cytometry analysis provided qualitative and quantitative evidence of a successful cellular internalization of siRNA. The peptides oleyl-(WRH)3 and oleyl-(WRH)4 showed ~60% and ~75% cellular uptake of siRNA, respectively, in both MDA-MB-231 and SK-OV-3 cells. Western blot analysis of oleyl-(WRH)4 demonstrated effective silencing of the STAT-3 gene, with ~75% silencing in MDA-MB-231 cells and ~45% in SK-OV-3 cells.

Advances in the preparation, characterization, and biological functions of chitosan oligosaccharide derivatives: A review

Chitosan oligosaccharide (COS), which represent the positively charged basic amino oligosaccharide in nature, is the deacetylated and degraded products of chitin. COS has become the focus of intensive scientific investigation, with a growing body of practical and clinical studies highlighting its remarkable health-enhancing benefits. These effects encompass a wide range of properties, including antibacterial, antioxidant, anti-inflammatory, and anti-tumor activities. With the rapid advancements in chemical modification technology for oligosaccharides, many COS derivatives have been synthesized and investigated. These newly developed derivatives possess more stable chemical structures, improved biological activities, and find applications across a broader spectrum of fields. Given the recent interest in the chemical modification of COS, this comprehensive review seeks to consolidate knowledge regarding the preparation methods for COS derivatives, alongside discussions on their structural characterization. Additionally, various biological activities of COS derivatives have been discussed in detail. Lastly, the potential applications of COS derivatives in biomedicine have been reviewed and presented.

Chitosan-Based Nanoparticles for Nucleic Acid Delivery: Technological Aspects, Applications, and Future Perspectives

Chitosan is a naturally occurring polymer derived from the deacetylation of chitin, which is an abundant carbohydrate found mainly in the shells of various marine and terrestrial (micro)organisms. Chitosan has been extensively used to construct nanoparticles (NPs), which are biocompatible, biodegradable, non-toxic, easy to prepare, and can function as effective drug delivery systems. Moreover, chitosan NPs have been employed in gene and vaccine delivery, as well as advanced cancer therapy, and they can also serve as new therapeutic tools against viral infections. In this review, we summarize the most recent developments in the field of chitosan-based NPs intended as nucleic acid delivery vehicles and gene therapy vectors. Special attention is given to the technological aspects of chitosan complexes for nucleic acid delivery.

Green synthesis of chitosan/polyacrylic acid/graphitic carbon nitride nanocarrier as a potential pH-sensitive system for curcumin delivery to MCF-7 breast cancer cells

A novel pH-sensitive nanocarrier containing chitosan (CS), polyacrylic acid (PAA), and graphitic carbon nitride (g-C₃N₄) was designed via water/oil/water (W/O/W) emulsification to administer curcumin (CUR) drug. g-C₃N₄ nanosheets with a high surface area and porous structure were produced via simple one-step pyrolysis process using thiourea as precursor, and incorporated into CS/PAA hydrogel. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) were used to assess the crystalline structure of the nanocarrier and the interactions between its components, respectively. Scanning electron microscopy (SEM) images revealed a spherical structure and confirmed the g-C₃N₄ impregnation into the CS/PAA matrix. Zeta potential and dynamic light scattering (DLS) provided information about the surface charge and average size distribution. High CUR loading and entrapment efficiencies were obtained, which were further improved upon addition of g-C₃N₄. The release kinetics of drug-loaded CS/PAA/g-C₃N₄ nanocomposites were investigated at pH = 5.4 and pH = 7.4, and the results showed an excellent controlled pH-sensitive release profile. Cell apoptosis and in vitro cytotoxicity were investigated using flow cytometry and MTT analyses. CS/PAA/g-C₃N₄/CUR resulted in the highest rate of apoptosis in MCF-7 breast cancer cells, demonstrating the excellent nanocomposite efficacy in eliminating cancerous cells. CS/PAA hydrogel coated with g-C₃N₄ shows great potential for pH-sensitive controlled drug release.

Chitosan and Its Structural Modifications for siRNA Delivery

The use of RNA interference mechanism and small interfering RNA (siRNA) in cancer gene therapy is a very promising approach. However, the success of gene silencing is underpinned by the efficient delivery of intact siRNA into the targeted cell. Nowadays, chitosan is one of the most widely studied non-viral vectors for siRNA delivery, since it is a biodegradable, biocompatible and positively charged polymer able to bind to the negatively charged siRNA forming nanoparticles (NPs) that will act as siRNA delivery system. However, chitosan shows several limitations such as low transfection efficiency and low solubility at physiological pH. Therefore, a variety of chemical and non-chemical structural modifications of chitosan were investigated in the attempt to develop a chitosan derivative showing the features of an ideal siRNA carrier. In this review, the most recently proposed chemical modifications of chitosan are outlined. The type of modification, chemical structure, physicochemical properties, siRNA binding affinity and complexation efficiency of the modified chitosan are discussed. Moreover, the resulting NPs characteristics, cellular uptake, serum stability, cytotoxicity and gene transfection efficiency in vitro and/or in vivo are described and compared to the unmodified chitosan. Finally, a critical analysis of a selection of modifications is included, highlighting the most promising ones for this purpose in the future.

Polysaccharides-Based Injectable Hydrogels: Preparation, Characteristics, and Biomedical Applications

Polysaccharides-based injectable hydrogels are a unique group of biodegradable and biocompatible materials that have shown great potential in the different biomedical fields. The biomolecules or cells can be simply blended with the hydrogel precursors with a high loading capacity by homogenous mixing. The different physical and chemical crosslinking approaches for preparing polysaccharide-based injectable hydrogels are reviewed. Additionally, the review highlights the recent work using polysaccharides-based injectable hydrogels as stimuli-responsive delivery vehicles for the controlled release of different therapeutic agents and viscoelastic matrix for cell encapsulation. Moreover, the application of polysaccharides-based injectable hydrogel in regenerative medicine as tissue scaffold and wound healing dressing is covered.

Synthesis, characterization, and cytotoxicity evaluation of dextran-myristoyl-ECGKRK peptide conjugate

CGKRK is a well-known tumor homing peptide with significant specificity for many types of cancer tissues. Herein, we describe the synthesis of a novel drug delivery system based on dextran decorated with myristoyl-ECGKRK peptide. The myristoylated peptide was synthesized and conjugated to dextran via an ester bond followed by purification. FT-IR and NMR confirmed the success of the conjugation reaction, while the surface morphology examination revealed that the conjugate has a characteristic porous network-like structure. Dynamic-light scattering measurements indicated the ability of the conjugate to self-assemble into nanoparticles with an average size of 248 ± 6.33 nm, and zeta potential of 10.7 mV. The cytotoxicity profiles for the peptide, dextran (Dex0), and dextran-peptide conjugate (Dex1) were evaluated against triple-negative breast cancer cells (MDA-MB-231), breast cancer cells (MCF-7), and human embryonic normal kidney cells (HEK-293). The results revealed that myristoyl-ECGKRK was noncytotoxic on the two different breast cancer cell lines up to 50 μM, but the cell viability was minimally reduced to 85% at 50 μm in HEK-293 cells. Similarly, Dex0 showed a neglected cytotoxicity profile at all tested concentrations. The Dex1 was not toxic to the cells up to a concentration of 8.3 mg/mL.

Antiproliferative Activity of Some Newly Synthesized Substituted Pyridine Candidates Using 4-(Aaryl)-6-(naphthalen-1-yl)-2-oxo-1,2-dihydropyridine-3-carbonitrile as Synthon

Herein, we used nicotinonitrile derivatives 4a,b as scaffolds to build novel and active antineoplastic agents. The reaction of nicotinonitrile derivatives 4a,b with POCl3/PCl5 and/or hydrazine hydrate afforded 2-chloropyridones 6a,b and 2-hydrazinyl nicotinonitrile derivatives 11a,b, respectively, as building blocks for various heterocyclic compounds. The structures of all of the synthesized heterocycles were elucidated from their spectral and elemental analyses. The cytotoxic activities of the prepared derivatives were evaluated against different cancer cell lines. Results revealed potential cytotoxic effects of the synthesized compounds against evaluated cell lines, where NCIH 460 and RKOP 27 cell lines were the most affected by the prepared compounds. Derivative 14a was the most effective against all tested cell lines in terms of the obtained IC50 values (25 ± 2.6, 16 ± 2, 127 ± 25, 422 ± 26, and 255 ± 2 nM against NCIH 460, RKOP 27, HeLa, U937, and SKMEL 28 cells, respectively).

Biomedical application of chitosan-based nanoscale delivery systems: Potential usefulness in siRNA delivery for cancer therapy

Gene therapy is an emerging and promising strategy in cancer therapy where small interfering RNA (siRNA) system has been deployed for down-regulation of targeted gene and subsequent inhibition in cancer progression; some issues with siRNA, however, linger namely, its off-targeting property and degradation by enzymes. Nanoparticles can be applied for the encapsulation of siRNA thus enhancing its efficacy in gene silencing where chitosan (CS), a linear alkaline polysaccharide derived from chitin, with superb properties such as biodegradability, biocompatibility, stability and solubility, can play a vital role. Herein, the potential of CS nanoparticles has been discussed for the delivery of siRNA in cancer therapy; proliferation, metastasis and chemoresistance are suppressed by siRNA-loaded CS nanoparticles, especially the usage of pH-sensitive CS nanoparticles. CS nanoparticles can provide a platform for the co-delivery of siRNA and anti-tumor agents with their enhanced stability via chemical modifications. As pre-clinical experiments are in agreement with potential of CS-based nanoparticles for siRNA delivery, and these carriers possess biocompatibiliy and are safe, further studies can focus on evaluating their utilization in cancer patients.

Research Advances in Chitosan Oligosaccharides: From Multiple Biological Activities to Clinical Applications

Chitosan oligosaccharides (COS), hydrolysed products of chitosan, are low-molecular weight polymers with a positive charge and good biocompatibility. COS have recently been reported to possess various biological activities, including hypoglycaemic, hypolipidaemic, antioxidantantioxidant, immune regulation, anti-inflammatory, antitumour, antibacterial, and tissue engineering activities, exhibiting extensive application prospects. Currently, the biological processes and mechanisms of COS are attractive topics of study, ranging from the genetic, molecular and protein levels. This article reviews the recent discoveries about COS, especially in metabolic regulation, immune function and tissue repair, providing important insights into their multiple biological activities, medical benefits, and therapeutic mechanisms.

Chitosan/carbon quantum dot/aptamer complex as a potential anticancer drug delivery system towards the release of 5-fluorouracil

Nowadays, nanotechnology contributes diminishing side effects rather than traditional therapeutic methods like chemotherapy. Thus, designing a biocompatible specific targeted nanocarrier with prolonged half-life and enhanced bio-availability using simultaneous cell imaging seems urgent. To meet this demand, 5-fluorouracil-chitosan‑carbon quantum dot-aptamer (5-FU-CS-CQD-Apt) nanoparticle was successfully synthesized for specific targeted delivery of 5-FU anti-cancer drug used in breast cancer treatment and this was done by following facile water-in-oil (W/O) emulsification method. Physicochemical properties were characterized and high drug loading and entrapment efficiency were achieved. The average size and zeta potential of the nanoparticle were 122.7 nm and + 31.2 mV, respectively. According to the in-vitro drug release profile, 5-FU-CS-CQD-Apt released the drug in a controlled manner. MTT assay, flow cytometry, fluorescence microscopy, and gene expression results demonstrated that the blank nanoparticle was biocompatible, and 5-FU-CS-CQD-Apt could kill tumor cells efficiently. Bcl-2/Bax ratio was decreased after 5-FU-CS-CQD-Apt treatment in MCF-7 cells. It was concluded that 5-FU-CS-CQD-Apt could be used as a potential nanocarrier in breast cancer treatment.

Preparation of 2,6-diurea-chitosan oligosaccharide derivatives for efficient antifungal and antioxidant activities

In this study, 2-urea-chitosan oligosaccharide derivatives (2-urea-COS derivatives) and 2,6-diurea-chitosan oligosaccharide derivatives (2,6-diurea-COS derivatives) were successfully designed and synthesized via intermediate 2-methoxyformylated chitosan oligosaccharide. All samples were characterized and compared based on FT-IR, ¹H NMR spectroscopy, and elemental analysis. The antifungal effects of COS derivatives were tested against Fusarium oxysporum f. sp. niveum, Phomopsis asparagus, and Botrytis cinereal. Their antioxidant properties, including superoxide radicals' scavenging activity, hydroxyl radicals' scavenging activity, and DPPH radicals' scavenging activity were also explored within different concentrations. COS derivatives bearing urea groups showed improved bioactivity compared with pristine COS and 2,6-diurea-COS derivatives had a higher biological activity than 2-urea-COS derivatives in tested concentrations. Additionally, L929 cells were used to carry out cytotoxicity test of COS and COS derivatives by CCK-8 assay. The results indicated that some of samples showed low cytotoxicity. These findings offered a suggestion that COS derivatives bearing urea groups are promising biological materials.

Effects of Chitosan Oligosaccharides on Human Blood Components

Chitosan oligosaccharide (COS) is known for its unique biological activities such as anti-tumor, anti-inflammatory, anti-oxidant, anti-bacterial activity, biological recognition, and immune enhancing effects, and thus continuous attracting many research interests in drug, food, cosmetics, biomaterials and tissue engineering fields. In comparison to its corresponding polymer, COS has much higher absorption profiles at the intestinal level, which results in permitting its quick access to the blood flow and potential contacting with blood components. However, the effects of COS on blood components remain unclear to date. Herein, two COS with different molecular weight (MW) were characterized by FTIR and ¹H NMR, and then their effects on human blood components, including red blood cells (RBCs) (hemolysis, deformability, and aggregation), coagulation system [activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and the concentration of fibrinogen (Fib)], complement (C3a and C5a activation), and platelet (activation and aggregation), were comprehensively studied. In the case of RBCs, COS exhibited a low risk of hemolysis in a dose and molecular weight dependent manner and the irreversible aggregation was observed in their high concentration. For coagulation system, COS has a mild anticoagulation activity through blocking the intrinsic coagulation pathway. In addition, COS showed no effect on complement activation in C3a and C5a and on platelet activation while inhibition of platelet aggregation was evident. Finally, the mechanism that effects of COS on blood components was discussed and proposed.

Interactions of oligochitosan with blood components

Oligochitosan (OCHI) is known to have some specific biological activities. However, its interactions with blood components and related correlation with molecular structures remains to be clarified due to its growing use in biomedical areas. Herein, a series of OCHI were prepared by hydrogen peroxide induced degradation combined fractionation in ethanol solutions and their molecular structures were characterized by GPC, FTIR, ¹H and ¹³C NMR, and then the interactions of the prepared OCHI with blood components, including red blood cells (hemolysis, deformability, and aggregation), coagulation system, complement (C3a, and C5a activation), and platelet (activation, and aggregation), were investigated. For red blood cells, OCHI has a quite low risk of hemolysis in a dose- and MW-dependent manner and the deformability and aggregation were observed in its high MW fraction. The coagulation tests revealed that OCHI is capable of a mild anticoagulation through blocking the intrinsic pathway and the anticoagulation corresponding MW was identified. In terms of complement, OCHI could inhibit C3a in a dose-dependent manner and activate C5a with its high MW fraction. In addition, there is no significant effect of OCHI on platelet activation and aggregation. Based on above results, the interactions related mechanism was discussed and proposed.

Micelle-like nanoparticles as siRNA and miRNA carriers for cancer therapy

Gene therapy has emerged as an alternative in the treatment of cancer, particularly in cases of resistance to chemo and radiotherapy. Different approaches to deliver genetic material to tumor tissues have been proposed, including the use of small non-coding RNAs due to their multiple mechanisms of action. However, such promise has shown limits in in vivo application related to RNA's biological instability and stimulation of immunity, urging the development of systems able to overcome those barriers. In this review, we discuss the use of RNA interference in cancer therapy with special attention to the role of siRNA and miRNA and to the challenges of their delivery in vivo. We introduce a promising class of drug delivery system known as micelle-like nanoparticles and explore their synthesis and advantages for gene therapy as well as the recent findings in in vitro, in vivo and clinical studies.