Synthesis of cationic quaternized pullulan derivatives for miRNA delivery

Semisynthesis of new sulfated heterorhamnan derivatives obtained from green seaweed Gayralia brasiliensis and evaluation of their anticoagulant activity

Marine green algae produce sulfated polysaccharides with diverse structures and a wide range of biological activities. This study aimed to enhance the biotechnological potential of sulfated heterorhamnan (Gb1) from Gayralia brasiliensis by chemically modifying it for improved or new biological functions. Using controlled Smith Degradation (GBS) and O-alkylation with 3-chloropropylamine, we synthesized partially water-soluble amine derivatives. GBS modification increase sulfate groups (29.3 to 37.5 %) and α-l-rhamnose units (69.9 to 81.2 mol%), reducing xylose and glucose, compared to Gb1. The backbone featured predominantly 3- and 2-linked α-l-rhamnosyl and 2,3- linked α-l-rhamnosyl units as branching points. Infrared and NMR analyses confirmed the substitution of hydroxyl groups with aminoalkyl groups. The modified compounds, GBS-AHCs and GBS-AHK, exhibited altered anticoagulant properties. GBS-AHCs showed reduced effectiveness in the APTT assay, while GBS-AHK maintained a similar anticoagulant activity level to Gb1 and GBS. Increased nitrogen content and N-alkylation in GBS-AHCs compared to GBS-AHK may explain their structural differences. The chemical modification proposed did not enhance its anticoagulant activity, possibly due to the introduction of amino groups and a positive charge to the polymer. This characteristic presents new opportunities for investigating the potential of these polysaccharides in various biological applications, such as antimicrobial and antitumoral activities.

Recent innovations (2020-2023) in the approaches for the chemical functionalization of curdlan and pullulan: A mini-review

Chemical modification represents a highly efficacious approach for enhancing the physicochemical characteristics and biological functionalities of natural polysaccharides. However, not all polysaccharides have considerable pharmacologic activity; so, appropriate chemical modification strategies can be selected in accordance with the distinct structural properties of polysaccharides to aid in improving and encouraging the presentation of their biological activities. Hence, there has been a growing interest in the chemical alteration of polysaccharides due to their various properties such as antioxidant, anticoagulant, antiviral, anticancer, biomedical, antibacterial, and immunomodulatory effects. This paper offers a comprehensive examination of recent scientific advancements produced over the past four years in the realm of unique chemical and functional modifications in curdlan and pullulan structures. This review aims to provide readers with an overview of the structural activity correlations observed in the backbone structures of curdlan and pullulan, as well as the diverse chemical modification processes employed for these polysaccharides. Additionally, the review aims to examine the effects of combining various bioactive molecules with chemically modified curdlan and pullulan and explore their potential applications in various important fields.

An injectable, self-healable, antibacterial, and pro-healing oxidized pullulan polysaccharide/carboxymethyl chitosan hydrogel for early protection of open abdominal wounds

Open abdomen (OA) is an effective method for treating critical abdominal conditions such as severe abdominal infections. The temporary abdominal closure (TAC) technique is often used to temporarily restore the physiological environment of the abdominal cavity and maintain the homeostatic balance of the abdominal cavity. However, most of the common TAC materials available today lack bio-responsiveness, tend to abrade the intestinal canal, and lead to delayed tissue healing of the wound. Hydrogels could mimic the extracellular matrix and have shown significant potential in life science fields such as tissue regeneration, wound repair, and controlled drug release. In this study, a composite hydrogel scaffold was constructed by the Schiff base reaction of oxidized pullulan polysaccharide with carboxymethyl chitosan. The hydrogel exhibited excellent self-healing, cellular biocompatibility, and antibacterial and anti-inflammatory abilities, and in experiments it reduced secondary damage caused by friction between tissue and patch, thereby preventing serious complications such as intestinal fistula, promoted M1-M2 polarization of macrophages, reduced the inflammatory response, regulated the inflammatory microenvironment in vivo, promoted angiogenesis and granulation tissue regeneration, and accelerated wound healing. Therefore, our hydrogel provides a new strategy for material-assisted wound protection during OA and has potential clinical applications.

Current Status and Trends in Nucleic Acids for Cancer Therapy: A Focus on Polysaccharide-Based Nanomedicines

The efficacious delivery of therapeutic nucleic acids to cancer still remains an open issue. Through the years, several strategies are developed for the encapsulation of genetic molecules exploiting different materials, such as viral vectors, lipid nanoparticles (LNPs), and polymeric nanoparticles (NPs). Indeed, the rapid approval by regulatory authorities and the wide use of LNPs complexing the mRNA coding for the spark protein for COVID-19 vaccination paved the way for the initiation of several clinical trials exploiting lipid nanoparticles for cancer therapy. Nevertheless, polymers still represent a valuable alternative to lipid-based formulations, due to the low cost and the chemical flexibility that allows for the conjugation of targeting ligands. This review will analyze the status of the ongoing clinical trials for cancer therapy, including vaccination and immunotherapy approaches, exploiting polymeric materials. Among those nanosized carriers, sugar-based backbones are an interesting category. A cyclodextrin-based carrier (CALAA-01) is the first polymeric material to enter a clinical trial complexed with siRNA for cancer therapy, and chitosan is one of the most characterized non-viral vectors able to complex genetic material. Finally, the recent advances in the use of sugar-based polymers (oligo- and polysaccharides) for the complexation of nucleic acids in advanced preclinical stage will be discussed.

Synthesis of Cationic Quaternized Nanolevan Derivative for Small Molecule and Nucleic Acid Delivery

Levan is a biopolymer composed of fructose chains covalently linked by β−2,6 glycosidic linkages. This polymer self−assembles into a nanoparticle of uniform size, making it useful for a wide range of applications. Also, levan exhibits various biological activities such as antioxidants, anti-inflammatory, and anti-tumor, that make this polymer very attractive for biomedical application. In this study, levan synthesized from Erwinia tasmaniensis was chemically modified by glycidyl trimethylammonium chloride (GTMAC) to produce cationized nanolevan (QA-levan). The structure of the obtained GTMAC−modified levan was determined by FT-IR, 1H-NMR and elemental (CHN) analyzer. The size of the nanoparticle was calculated using the dynamic light scattering method (DLS). The formation of DNA/QA-levan polyplex was then investigated by gel electrophoresis. The modified levan was able to increase the solubility of quercetin and curcumin by 11-folds and 205-folds, respectively, compared to free compounds. Cytotoxicity of levan and QA−levan was also investigated in HEK293 cells. This finding suggests that GTMAC−modified levan should have a potential application for drug and nucleic acid delivery.

Cationic Pullulan Derivatives Based Flocculants for Removal of Some Metal Oxides from Simulated Wastewater

Modified polysaccharides have been increasingly used as flocculants in wastewater treatment due to their non-toxicity, low price, biodegradability, etc. However, the pullulan derivatives are less used in wastewater purification processes. Therefore, this article presents some data regarding FeO and TiO₂ particle removal from model suspensions by some pullulan derivatives with pendant quaternary ammonium salt groups, trimethylammonium propyl carbamate chloride (TMAP_x-P). The influence of the polymer ionic content, dose, and initial solution concentration as well as of the dispersion pH and composition (metal oxide content, salts, and kaolin) on the separation efficacy were considered. UV-Vis spectroscopy measurements have shown a very good removal efficacy of TMAP_x-P for the FeO particles (around 95% and more), irrespective of the polymer and suspension characteristics; a lower clarification of the TiO₂ particles suspension (removal efficiency between 68% and 75%) was noticed. Both the zeta potential and the particle aggregates size measurements revealed the charge patch as the main mechanism which governs the metal oxide removal process. The surface morphology analysis/EDX data provided supplementary evidence regarding the separation process. A good removal efficiency (90%) of the pullulan derivatives/FeO flocs for the Bordeaux mixture particles from simulated wastewater was found.

High-level production of pullulan and its biosynthesis regulation in Aureobasidium pullulans BL06

Pullulan has many potential applications in the food, pharmaceutical, cosmetic and environmental industries. However, the yield and molecular properties of pullulan produced by various strains still need to be promoted to fit the application needs. A novel yeast-like strain Aureobasidium pullulans BL06 producing high molecular weight (Mw) pullulan (3.3 × 10⁶ Da) was isolated and identified in this study. The remarkable Mw of pullulan produced by A. pullulans BL06 was the highest level ever reported thus far. To further regulate the biosynthesis of pullulan in A. pullulans BL06, three gene knockout strains A. pullulans BL06 ΔPMAs, A. pullulans BL06 Δmel, and A. pullulans BL06 ΔPMAsΔmel, were constructed. The results showed that A. pullulans BL06 ΔPMAs could produce 140.2 g/L of moderate Mw (1.3 × 10⁵ Da) pullulan after 120 h of fermentation. The highest yield level of pullulan to date could vastly reduce its production cost and expand its application scope and potential. The application experiments in food preservation showed that the moderate-Mw pullulan obtained in this work could reduce the weight loss of celery cabbages and mangos by 12.5% and 22%, respectively. Thus, the novel strains A. pullulans BL06 and A. pullulans BL06 ΔPMAs possessed unlimited development prospects in pullulan production at various Mw ranges and pullulan applications in multiple fields.

Polysaccharide hydrogels: Functionalization, construction and served as scaffold for tissue engineering

Polysaccharide hydrogels have been widely utilized in tissue engineering. They interact with the organismal environments, modulating the cargos release and realizing of long-term survival and activations of living cells. In this review, the potential strategies for modification of polysaccharides were introduced firstly. It is not only used to functionalize the polysaccharides for the consequent formation of hydrogels, but also used to introduce versatile side groups for the regulation of cell behavior. Then, techniques and underlying mechanisms in inducing the formation of hydrogels by polysaccharides or their derivatives are briefly summarized. Finally, the applications of polysaccharide hydrogels in vivo, mainly focus on the performance for alleviation of foreign-body response (FBR) and as cell scaffolds for tissue regeneration, are exemplified. In addition, the perspectives and challenges for further research are addressed. It aims to provide a comprehensive framework about the potentials and challenges that the polysaccharide hydrogels confronting in tissue engineering.

Nanoparticulate strategies for the delivery of miRNA mimics and inhibitors in anticancer therapy and its potential utility in oral submucous fibrosis

MicroRNAs (miRNAs) are naturally occurring noncoding RNAs with multiple functionalities. They are dysregulated in several conditions and can serve as disease biomarkers, therapeutic targets and therapeutic agents. Translation of miRNA therapeutics to the clinic poses several challenges related to the safe and effective delivery of these agents to the site of action. Nanoparticulate carriers hold promise in this area by enhancing targeting efficiency and reducing off-target effects. This paper reviews recent advances in the delivery strategies of miRNAs in anticancer therapy, with a focus on lipid-based, polymeric, inorganic platforms, cell membrane-derived vesicles and bacterial minicells. Additionally, this review explores the potentiality of miRNAs in the treatment of oral submucous fibrosis, a potentially premalignant condition of the oral cavity with no definitive treatment to date.

Drug Targeting of Inflammatory Bowel Diseases by Biomolecules

Inflammatory bowel disease (IBD) is a group of disabling, destructive and incurable immune-mediated inflammatory diseases comprising Crohn’s disease (CD) and ulcerative colitis (UC), disorders that are highly prevalent worldwide and demand a large investment in healthcare. A persistent inflammatory state enables the dysfunction and destruction of healthy tissue, hindering the initiation and endurance of wound healing. Current treatments are ineffective at counteracting disease progression. Further, increased risk of serious side effects, other comorbidities and/or opportunistic infections highlight the need for effective treatment options. Gut microbiota, the key to preserving a healthy state, may, alternatively, increase a patient’s susceptibility to IBD onset and development given a relevant bacterial dysbiosis. Hence, the main goal of this review is to showcase the main conventional and emerging therapies for IBD, including microbiota-inspired untargeted and targeted approaches (such as phage therapy) to infection control. Special recognition is given to existing targeted strategies with biologics (via monoclonal antibodies, small molecules and nucleic acids) and stimuli-responsive (pH-, enzyme- and reactive oxygen species-triggered release), polymer-based nanomedicine that is specifically directed towards the regulation of inflammation overload (with some nanosystems additionally functionalized with carbohydrates or peptides directed towards M1-macrophages). The overall goal is to restore gut balance and decrease IBD’s societal impact.

Bioactivity of Chitosan-Based Particles Loaded with Plant-Derived Extracts for Biomedical Applications: Emphasis on Antimicrobial Fiber-Based Systems

Marine-derived chitosan (CS) is a cationic polysaccharide widely studied for its bioactivity, which is mostly attached to its primary amine groups. CS is able to neutralize reactive oxygen species (ROS) from the microenvironments in which it is integrated, consequently reducing cell-induced oxidative stress. It also acts as a bacterial peripheral layer hindering nutrient intake and interacting with negatively charged outer cellular components, which lead to an increase in the cell permeability or to its lysis. Its biocompatibility, biodegradability, ease of processability (particularly in mild conditions), and chemical versatility has fueled CS study as a valuable matrix component of bioactive small-scaled organic drug-delivery systems, with current research also showcasing CS’s potential within tridimensional sponges, hydrogels and sutures, blended films, nanofiber sheets and fabric coatings. On the other hand, renewable plant-derived extracts are here emphasized, given their potential as eco-friendly radical scavengers, microbicidal agents, or alternatives to antibiotics, considering that most of the latter have induced bacterial resistance because of excessive and/or inappropriate use. Loading them into small-scaled particles potentiates a strong and sustained bioactivity, and a controlled release, using lower doses of bioactive compounds. A pH-triggered release, dependent on CS’s protonation/deprotonation of its amine groups, has been the most explored stimulus for that control. However, the use of CS derivatives, crosslinking agents, and/or additional stabilization processes is enabling slower release rates, following extract diffusion from the particle matrix, which can find major applicability in fiber-based systems within ROS-enriched microenvironments and/or spiked with microbes. Research on this is still in its infancy. Yet, the few published studies have already revealed that the composition, along with an adequate drug release rate, has an important role in controlling an existing infection, forming new tissue, and successfully closing a wound. A bioactive finishing of textiles has also been promoting high particle infiltration, superior washing durability, and biological response.