Pullulan and pullulan derivatives as promising biomolecules for drug and gene targeting

Bio-inspired, programmable biomacromolecules based nanostructures driven cancer therapy

Cancer remains a significant global health challenge, driving the development of advanced platforms for highly targeted and efficient drug delivery. Early-stage nanocarriers, such as synthetic polymeric and inorganic materials, face limitations in biocompatibility and biodegradability. In contrast, bioinspired nanocarriers derived from natural biomacromolecules mimic biological processes and present a promising alternative due to their biocompatibility, biodegradability and non-toxicity. The effectiveness of these drug delivery systems is influenced by factors such as size, shape, surface properties, morphology, functionalization, and preparation methods. Various biomacromolecule-inspired nanocarriers such as protein-based, lipid-based, carbohydrate-based and nucleic acid-based are now at the forefront of research. This review highlights the properties, advantages and limitations of different bioinspired materials. We also explore cutting-edge approaches for cancer therapy using these nanocarriers with recent in-vitro, in-vivo and patent evidence. Finally, we address the challenges and potential solutions associated with bioinspired nanocarriers, proposing future directions. Overall, this review explores nature-inspired drug delivery systems that have paved the way for advancements in cancer therapy.

Pullulan as a sustained release carrier for ocular drug delivery: a review

Pullulan, an exopolysaccharide, obtained from the fungus Aureobasidium pullulans, is a non-ionic, hydrophilic, biodegradable, biocompatible, and tolerogenic polymers that is used for the formulation of bioconjugates in the therapeutic delivery to target different cells and tissues. It is known to possess outstanding film-casting qualities and can produce a clear and biodegradable film. Furthermore, appropriate derivatizing pullulan provides active surfaces that facilitate binding with active pharmaceutical ingredients to the polymer backbone to produce micro/nanoparticulate systems for controlled or sustained drug release. Ophthalmic problems like glaucoma, age-related macular degeneration, and cataracts are very prevalent across the globe, and their treatment options mainly include conventional topical solutions and gels, which possess very low drug-contact time and poor bioavailability, leading to frequent dosing and patient incompliance. Sustained release dosage forms like ocuserts, ocular films, and in-situ gels can help in achieving the intended therapeutic outcomes for an extended duration by minimizing the number of doses. Here, we present a comprehensive critical review of the utilization and application of pullulan, together with its derivatives, to combat problems with ocular medication administration. This article also provides insight for further research on this topic to utilize its advantages to the fullest in the future for improved delivery of therapeutics in the treatment of ocular disorders.

Design of pH-responsive and amphiphilic pullulan-based biological macromolecule for gene delivery

Nanomedicine, particularly gene delivery, holds immense potential and offers promising therapeutic options. Non-viral systems gained attention due to their binding capacity, stability and scalability. Among these, natural polysaccharides, such as pullulan, are advantageous in terms of sustainability, biocompatibility and potential degradability. In our study, a pH-responsive and amphiphilic pullulan derivative, pullulan norbornene carboxylate (PNC-DMA) was developed, by a two-step synthetic process involving esterification with hydrophobic norbornene group and radical thiol-ene reaction to introduce a pH-dependent cationic group. The molar mass of the polymer was systematically varied to adjust its hydrophobicity and pH-responsive properties, with DS values ranging from 0.4 to 1.4. The created pullulan library exhibited apparent pKa values between 6.5 and 7.1, which were inversely proportional to the degree of substitution (DS). This increase enhanced the polymer's affinity for genetic material, facilitated responsive complexation, provided protection against DNase, and boosted transfection efficiency. However, increased DS was associated with cytotoxicity and protein interaction. Thus, PNC-DMA(140) emerged as the most promising candidate for aqueous formulation and gene delivery in HEK293T cells, even in the presence of serum proteins. This structure-activity-relationship study paves the way for further exploration of the potential advantages of using polysaccharides in gene delivery applications.

Enhanced Specificity in Colorimetric LAMP Assay for Sarocladium kiliense Detection Using a Combination of Two Additives

The genus Sarocladium comprises fungal species closely related to Acremonium, with S. kiliense and S. strictum being medically important. These species can cause infections in both immunocompetent and immunocompromised individuals. The current detection methods are limited, prompting the need for rapid and specific diagnostic tools. We developed a colorimetric loop-mediated isothermal amplification (LAMP) assay targeting S. kiliense (SK-LAMP). The initial prototype assay faced challenges with cross-reactivities with closely related species. To address this, we incorporated two additives, pullulan and tetramethylammonium chloride (TMAC), which are known to reduce non-specific signals in amplification assays. Our study found that a combination of 1% (v/v) pullulan and 0.03 M TMAC enhanced the specific detection of S. kiliense in a 45 min reaction, without non-specific false-positive results for other fungal species. This optimised LAMP assay demonstrated high sensitivity and specificity, offering a reliable and rapid method for detecting S. kiliense. The novel approach of combining additives to enhance assay specificity presents a promising strategy for improving LAMP assays targeting closely related fungal species. This advancement can aid in the timely diagnosis and management of infections caused by S. kiliense, contributing to better patient outcomes and infection control.

Polymeric liposomes of emtricitabine employing modified pullulan-an attempt to reduce associated hepatotoxicity

Emtricitabine (FTC) a BCS class I drug, is used for HIV prevention. The high solubility of the drug is the leading cause of severe hepatotoxicity and lactic acidosis. This research focuses on the use of modified pullulan for the preparation of polymeric liposomes of FTC. Modified pullulan was synthesized using cholesterol, and succinic anhydride in a controlled chemical environment. The formation of the polymer was established through analysis of spectra. Varying the drug-polymer ratio (1:1, 1:2, and 1:3), the drug-polymer composite was loaded in the vesicular system of soya phosphatidylcholine and cholesterol. Formulations were evaluated for drug entrapment, particle size, surface morphology, and in vitro and ex vivo drug release. An in vivo study of the pure drug and the best formulation on mice was conducted for 28 days following daily oral administration to evaluate the effect on liver and hematological parameters. The best formulation was further subjected to cytotoxicity study on hepatic cell lines. Spectral analysis confirmed the formation of modified pullulan. All formulations showed high drug entrapment in the nanovesicles. The in vitro and ex vivo drug release profiles depicted a controlled release of the drug. Hematological parameters were found to be under control in the animals throughout the experimentation. A comparative histopathology study on the livers and cytotoxicity study on hepatic cell lines revealed the safety of the best formulation over the pure drug. Hence it can be concluded that polymeric liposomes of FTC can be a promising mode of delivery to overcome its limitations.

Polymers as Efficient Non-Viral Gene Delivery Vectors: The Role of the Chemical and Physical Architecture of Macromolecules

Gene therapy is the technique of inserting foreign genetic elements into host cells to achieve a therapeutic effect. Although gene therapy was initially formulated as a potential remedy for specific genetic problems, it currently offers solutions for many diseases with varying inheritance patterns and acquired diseases. There are two major groups of vectors for gene therapy: viral vector gene therapy and non-viral vector gene therapy. This review examines the role of a macromolecule's chemical and physical architecture in non-viral gene delivery, including their design and synthesis. Polymers can boost circulation, improve delivery, and control cargo release through various methods. The prominent examples discussed include poly-L-lysine, polyethyleneimine, comb polymers, brush polymers, and star polymers, as well as hydrogels and natural polymers and their modifications. While significant progress has been made, challenges still exist in gene stabilization, targeting specificity, and cellular uptake. Overcoming cytotoxicity, improving delivery efficiency, and utilizing natural polymers and hybrid systems are vital factors for prospects. This comprehensive review provides an illuminating overview of the field, guiding the way toward innovative non-viral-based gene delivery solutions.

Mechanical Stretching of Nature Inspired Linear and Branched Polysaccharide Motifs through Steered Molecular Dynamics

A variety of 10 polysaccharide motifs comprising naturally inspired sequences of monosaccharide building blocks are studied to understand the inter-relation between their structural and mechanical behaviors. Equilibrium and steered molecular dynamics (SMD) simulations are employed to investigate the stress-strain relationships and the associated conformational flips of the pyranose moieties along the polysaccharide chains. The presence of a variety of glycosidic linkages connecting the diverse monosaccharide units along with chain-branching in some cases induce wide diversity in the carbohydrate-Ramachandran plots of the glycosidic dihedrals. Similar variations are observed in the Cremer-Pople ring puckering patterns across the polysaccharide variants. The work further provides a comparison between the experimentally obtained atomic force microscopic data of mechanical stretching for some polysaccharides with the stress-strain curves generated from our SMD simulations. Out of all the systems studied, pectin having an axial-axial orientation of the glycosidic linkage showed maximum stretching potential, while acetan-M, with an equatorial-equatorial disposition of the glycosidic bond, stretched the least. The experimental Young's modulus of the corresponding natural polysaccharides could be reasonably compared to the values obtained from our simulation models. Force distribution analysis is done to understand the propagation of punctual stress in the polysaccharides under SMD conditions. Changes in local electrophilicity or nucleophilicity of atomic centers in puckered pyranose rings are estimated through the condensed Fukui functions. All of this information can help understand the physical behavior and chemical reactivity of complex polysaccharides in a complicated milieu of electronic and steric effects experienced by them.

The impacts of pullulan soaking on radish seed germination and seedling growth under salt stress

Pullulan can not only provide a source of organic carbon but also has excellent properties. However, current research is mostly limited to the physical properties of the high-molecular-weight components of pullulan, and little is known about the application of its low-molecular-weight components. This study was designed to explore the impact of presoaking of radish seeds in a pullulan solution on seed germination and subsequent seedling growth under salt stress conditions. Pullulan soaking was found to enhance the germination rates of radish seeds subjected to salt stress, while also enhancing the aboveground growth of radish seedlings. Pullulan soaking resulted in increases in chlorophyll, soluble protein, and soluble sugar concentrations in the leaves of these seedlings, together with greater peroxidase activity and root activity as well as decreases in Na+ and malondialdehyde concentrations. This provides an important reference for the application of pullulan in plant protection.

A structure-functionality insight into the bioactivity of microbial polysaccharides toward biomedical applications: A review

Microbial polysaccharides (MPs) are biopolymers secreted by microorganisms such as bacteria and fungi during their metabolic processes. Compared to polysaccharides derived from plants and animals, MPs have advantages such as wide sources, high production efficiency, and less susceptibility to natural environmental influences. The most attractive feature of MPs lies in their diverse biological activities, such as antioxidative, anti-tumor, antibacterial, and immunomodulatory activities, which have demonstrated immense potential for applications in functional foods, cosmetics, and biomedicine. These bioactivities are precisely regulated by their sophisticated molecular structure. However, the mechanisms underlying this precise regulation are not yet fully understood and continue to evolve. This article presents a comprehensive review of the most representative species of MPs, including their fermentation and purification processes and their biomedical applications in recent years. In particular, this work presents an in-depth analysis into the structure-activity relationships of MPs across multiple molecular levels. Additionally, this review discusses the challenges and prospects of investigating the structure-activity relationships, providing valuable insights into the broad and high-value utilization of MPs.

Berberine encapsulated phenylboronic acid-conjugated pullulan nanoparticles: Synthesis, characterization and anticancer activity validated in A431 skin cancer cells and 3D spheroids

Polysaccharide-based drug delivery systems are in high demand due to their biocompatibility, non-toxicity, and low-cost. In this study, sialic acid receptor targeted 4-carboxy phenylboronic acid modified pullulan-stearic acid conjugate (4-cPBA-PUL-SA) was synthesized and characterized for the delivery of Berberine (BBR). BBR-loaded 4-cPBA-PUL-SA nanoparticles (BPPNPs) were monodispersed (PDI: 0.238 ± 0.07), with an average hydrodynamic particle size of 191.6 nm and 73.6 % encapsulation efficiency. BPPNPs showed controlled BBR release and excellent colloidal stability, indicating their potential for drug delivery application. The cytotoxicity results indicated that BPPNPs exhibited dose and time-dependent cytotoxicity against human epidermoid carcinoma cells (A431) as well as 3D spheroids. Targeted BPPNPs demonstrated significantly higher anticancer activity compared to BBR and non-targeted BPNPs. The IC50 values for BPPNPs (2.29 μg/ml) were significantly lower than BPNPs (4.13 μg/ml) and BBR (19.61 μg/ml), indicating its potential for skin cancer treatment. Furthermore, CSLM images of A431 cells and 3D spheroids demonstrated that BPPNPs have higher cellular uptake and induced apoptosis compared to free BBR and BPNPs. In conclusion, BPPNPs demonstrate promising potential as an effective drug delivery system for skin cancer therapy.

Optimization of pullulan production by Aureobasidium pullulans using semi-solid-state fermentation and artificial neural networks: Characterization and antibacterial activity of pullulan impregnated with Ag-TiO2 nanocomposite

This study presents a novel and efficient approach for pullulan production using artificial neural networks (ANNs) to optimize semi-solid-state fermentation (S-SSF) on faba bean biomass (FBB). This method achieved a record-breaking pullulan yield of 36.81 mg/g within 10.82 days, significantly exceeding previous results. Furthermore, the study goes beyond yield optimization by characterizing the purified pullulan, revealing its unique properties including thermal stability, amorphous structure, and antioxidant activity. Energy-dispersive X-ray spectroscopy and scanning electron microscopy confirmed its chemical composition and distinct morphology. This research introduces a groundbreaking combination of ANNs and comprehensive characterization, paving the way for sustainable and cost-effective pullulan production on FBB under S-SSF conditions. Additionally, the study demonstrates the successful integration of pullulan with Ag@TiO2 nanoparticles during synthesis using Fusarium oxysporum. This novel approach significantly enhances the stability and efficacy of the nanoparticles by modifying their surface properties, leading to remarkably improved antibacterial activity against various human pathogens. These findings showcase the low-cost production medium, and extensive potential of pullulan not only for its intrinsic properties but also for its ability to significantly improve the performance of nanomaterials. This breakthrough opens doors to diverse applications in various fields.

Nutritive profile, pharmaceutical potentials, and structural analysis of multifunctional bioactive fungal polysaccharides-A review

Asian nations have long used edible fungi as food and medicine. Polysaccharides are among the main building units of the cell walls of fungi. Fungal polysaccharides have been documented in the medicinal and industrial sectors as products with a vast array of various biological activities and applications such as antitumor, antioxidant, anticancer, immunomodulation, and antiviral activities, etc. The goal of this review is to give insights into the various biological activities of mushroom polysaccharides and their potential as a medicine for human health. The extraction, purity, and structural analysis of fungal polysaccharides were also reviewed in this work. Also, future prospective, and challenges for fungal polysaccharides in pharmaceutical applications can be found in this review. Overall, this review serves as a valuable resource in exploring the therapeutic potential and applications of fungal polysaccharides. By building upon the existing knowledge base and addressing critical research gaps, researchers can find new opportunities for utilizing fungal polysaccharides as valuable therapeutic agents and functional ingredients in pharmaceuticals, nutraceuticals, and biotechnology.

Chitosan-Oxidized Pullulan Hydrogels Loaded with Essential Clove Oil: Synthesis, Characterization, Antioxidant and Antimicrobial Properties

Emulsion hydrogels are promising materials for encapsulating and stabilizing high amounts of hydrophobic essential oils in hydrophilic matrices. In this work, clove oil-loaded hydrogels (CS/OP-C) are synthesized by combining covalent and physical cross-linking approaches. First, clove oil (CO) was emulsified and stabilized in a chitosan (CS) solution, which was further hardened by Schiff base covalent cross-linking with oxidized pullulan (OP). Second, the hydrogels were subjected to freeze-thaw cycles and, as a result, the clove oil was stabilized in physically cross-linked polymeric walls. Moreover, due to cryogelation, the obtained hydrogels exhibited sponge-like porous interconnected morphology (160-250 µm). By varying the clove oil content in the starting emulsion and the degree of cross-linking, the hydrogels displayed a high water retention capacity (swelling ratios between 1300 and 2000%), excellent elastic properties with fast shape recovery (20 s) after 70% compression, and controlled in vitro clove oil release in simulated skin conditions for 360 h. Furthermore, the prepared clove oil-loaded hydrogels had a strong scavenging activity of 83% and antibacterial and antifungal properties, showing a bacteriostatic effect after 48 and 72 h against S. aureus and E. coli. Our results recommend the new clove oil-embedded emulsion hydrogels as promising future materials for application as wound dressings.

Exploring the potential of pullulan-based films and coatings for effective food preservation: A comprehensive analysis of properties, activation strategies and applications

Pullulan is naturally occurring polysaccharide exhibited potential applications for food preservation has gained increasing attention over the last half-century. Recent studies focused on efficient preservation and targeted inhibition using active composite ingredients and advanced technologies. This has led to the emergence of pullulan-based biofilm preservation. This review extensively studied the characteristics of pullulan-based films and coatings, including their mechanical strength, water vapor permeability, thermal stability, and potential as a microbial agent. Furthermore, the distinct characteristics of pullulan, production methods, and activation strategies, such as pullulan derivatization, various compounded ingredients (plant extracts, microorganisms, and animal additives), and other technologies (e.g., ultrasound), are thoroughly studied for the functional property enhancement of pullulan-based films and coatings, ensuring optimal preservation conditions for diverse food products. Additionally, we explore hypotheses that further illuminate pullulan's potential as an eco-friendly bioactive material for food packaging applications. In addition, this review evaluates various methods to improve the efficiency of the film-forming mechanism, such as improving the direct coating process, bioactive packaging films, and implementing layer-by-layer coatings. Finally, current analyses put forward suggestions for future advancement in pullulan-based bioactive films, with the aim of expanding their range of potential applications.

Unlocking the power of sugar: carbohydrate ligands as key players in nanotherapeutic-assisted targeted cancer therapy

Cancer cells need as much as 40-times more sugar than their normal cell counterparts. This sugar demand is attained by the excessive expression of inimitable transporters on the surface of cancer cells, driven by their voracious appetite for carbohydrates. Nanotechnological advances drive research utilizing ligand-directed therapeutics and diverse carbohydrate analogs. The precise delivery of these therapeutic cargos not only mitigates toxicity associated with chemotherapy but also reduces the grim toll of mortality and morbidity among patients. This in-depth review explores the potential of these ligands in advanced cancer treatment using nanoparticles. It offers a broader perspective beyond the usual ways we deliver drugs, potentially changing the way we fight cancer.

Pullulan-Graft-Polyoxazoline: Approaches from Chemistry and Physics

An approach to the preparation of pullulan-graft-poly(2-methyl-2-oxazoline)s based on Cu-catalyzed azide-alkyne cycloaddition with polyoxazoline-azide was applied. All of the obtained polymers were characterized through classical molecular hydrodynamic methods and NMR. The formation of graft copolymers was accomplished by oxidative degradation of pullulan chains. Nevertheless, graft copolymers were obtained as uniform products with varied side chain lengths and degrees of substitution.

Oxidized pullulan exhibits potent antibacterial activity against S. aureus by disrupting its membrane integrity

The capability of bacteria to withstand the misuse of antibiotics leads to the generation of multi-drug resistant strains, posing a new challenge to curb wound infections. The biological macromolecules, due to their biocompatibility, biodegradability, and antimicrobial properties, have been explored for a variety of antimicrobial and therapeutic purposes. This work reports that a single-step oxidation of pullulan polymer leads to the formation of oxidized pullulan (o-pullulan), which shows striking antibacterial and antibiofilm activities against the Gram-positive bacteria, Staphylococcus aureus, implicated in wound-related infections. Oxidation of pullulan generates 28 % aldehyde groups (3.462 mmol/g) which exerted 97 % bactericidal activity against S. aureus by targeting cell wall-associated membrane protein SpA (Staphylococcal protein A). The molecular docking, gene silencing, and fluorescence quenching studies revealed a direct binding of o-pullulan with the B and C domains of SpA, which alters the membrane potential and inhibits Ca2+-Mg2+-ATPase pumps. O-pullulan also exhibited scavenging activity against intracellular reactive oxygen species (ROS), and non-immunotoxic activity and was found to be non-toxic to mammalian cells. Thus, o-pullulan shows great promise as an antimicrobial polymer against S. aureus for chronic wound management.

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.

Polysaccharide-based nanoassemblies: From synthesis methodologies and industrial applications to future prospects

Polysaccharides, due to their remarkable features, have gained significant prominence in the sustainable production of nanoparticles (NPs). High market demand and minimal production cost, compared to the chemically synthesised NPs, demonstrate a drive towards polysaccharide-based nanoparticles (PSNPs) benign to environment. Various approaches are used for the synthesis of PSNPs including cross-linking, polyelectrolyte complexation, and self-assembly. PSNPs have the potential to replace a wide diversity of chemical-based agents within the food, health, medical and pharmacy sectors. Nevertheless, the considerable challenges associated with optimising the characteristics of PSNPs to meet specific targeting applications are of utmost importance. This review provides a detailed compilation of recent accomplishments in the synthesis of PSNPs, the fundamental principles and critical factors that govern their rational fabrication, as well as various characterisation techniques. Noteworthy, the multiple use of PSNPs in different disciplines such as biomedical, cosmetics agrochemicals, energy storage, water detoxification, and food-related realms, is accounted in detail. Insights into the toxicological impacts of the PSNPs and their possible risks to human health are addressed, and efforts made in terms of PSNPs development and optimising strategies that allow for enhanced delivery are highlighted. Finally, limitations, potential drawbacks, market diffusion, economic viability and future possibilities for PSNPs to achieve widespread commercial use are also discussed.

Traversing the diverse avenues of exopolysaccharides-based nanocarriers in the management of cancer

Exopolysaccharides are unique polymers generated by living organisms such as algae, fungi and bacteria to protect them from environmental factors. After a fermentative process, these polymers are extracted from the medium culture. Exopolysaccharides have been explored for their anti-viral, anti-bacterial, anti-tumor, and immunomodulatory effects. Specifically, they have acquired massive attention in novel drug delivery strategies owing to their indispensable properties like biocompatibility, biodegradability, and lack of irritation. Exopolysaccharides such as dextran, alginate, hyaluronic acid, pullulan, xanthan gum, gellan gum, levan, curdlan, cellulose, chitosan, mauran, and schizophyllan exhibited excellent drug carrier properties. Specific exopolysaccharides, such as levan, chitosan, and curdlan, have demonstrated significant antitumor activity. Moreover, chitosan, hyaluronic acid and pullulan can be employed as targeting ligands decorated on nanoplatforms for effective active tumor targeting. This review shields light on the classification, unique characteristics, antitumor activities and nanocarrier properties of exopolysaccharides. In addition, in vitro human cell line experiments and preclinical studies associated with exopolysaccharide-based nanocarriers have also been highlighted.

Production and applications of pullulan from lignocellulosic biomass: Challenges and perspectives

Pullulan is an exopolysaccharide produced by Aureobasidium pullulans, with interesting characteristics which lead to its application in industries such as pharmaceuticals, cosmetics, food, and others. To reduce production costs for industrial applications, cheaper raw materials such as lignocellulosic biomass can be utilized as a carbon and nutrient source for the microbial process. In this study, a comprehensive and critical review was conducted, encompassing the pullulan production process and the key influential variables. The main properties of the biopolymer were presented, and different applications were discussed. Subsequently, the utilization of lignocellulosics for pullulan production within the framework of a biorefinery concept was explored, considering the main published works that deal with materials such as sugarcane bagasse, rice husk, corn straw, and corn cob. Next, the main challenges and future prospects in this research area were highlighted, indicating the key strategies to favor the industrial production of pullulan from lignocellulosic biomasses.

Dual functional pullulan-based spray-dried microparticles for controlled pulmonary drug delivery

Two main challenges are associated with current spray-dried microparticles for inhalation, including the enhancement of aerosolization performance of microparticles and the creation of sustained drug release for continuous treatment on-site. For achieving these purposes, pullulan was explored as a novel excipient to prepare spray-dried inhalable microparticles (with salbutamol sulphate, SS, as a model drug), which were further modified by additives of leucine (Leu), ammonium bicarbonate (AB), ethanol and acetone. It was demonstrated that all pullulan-based spray-dried microparticles had improved flowability and enhanced aerosolization behavior, with the fine particle (<4.46µm) fraction of 42.0-68.7% w/w, much higher than 11.4% w/w of lactose-SS. Moreover, all modified microparticles showed augmented emitted fractions of 88.0-96.9% w/w, over 86.5% w/w of pullulan-SS. The pullulan-Leu-SS and pullulan-(AB)-SS microparticles demonstrated further increased fine particle (<1.66µm) doses of 54.7µg and 53.3µg respectively, surpassing that (49.6µg) of pullulan-SS, suggesting an additionally increased drug deposition in the deep lungs. Furthermore, pullulan-based microparticles revealed sustained drug release profiles with elongated time (60mins) over the control (2mins). Clearly, pullulan has a great potential to construct dual functional microparticles for inhalation with improved pulmonary delivery efficiency and sustained drug release on-site.

Poloxamer/Carboxymethyl Pullulan Aqueous Systems-Miscibility and Thermogelation Studies Using Viscometry, Rheology and Dynamic Light Scattering

Thermally-induced gelling systems based on Poloxamer 407 (PL) and polysaccharides are known for their biomedical applications; however, phase separation frequently occurs in mixtures of poloxamer and neutral polysaccharides. In the present paper, the carboxymethyl pullulan (CMP) (here synthesized) was proposed for compatibilization with poloxamer (PL). The miscibility between PL and CMP in dilute aqueous solution was studied by capillary viscometry. CMP with substitution degrees higher than 0.5 proved to be compatible with PL. The thermogelation of concentrated PL solutions (17%) in the presence of CMP was monitored by the tube inversion method, texture analysis and rheology. The micellization and gelation of PL in the absence or in the presence of CMP were also studied by dynamic light scattering. The critical micelle temperature and sol-gel transition temperature decrease with the addition of CMP, but the concentration of CMP has a peculiar influence on the rheological parameters of the gels. In fact, low concentrations of CMP decrease the gel strength. With a further increase in polyelectrolyte concentration, the gel strength increases until 1% CMP, then the rheological parameters are lowered again. At 37 °C, the gels are able to recover the initial network structure after high deformations, showing a reversible healing process.

A practical approach to producing the single-arm linear dextrin, a chimeric glucosaccharide containing an (α-1 → 4) linked portion at the nonreducing end of an (α-1 → 6) glucochain

How to improve the solubility of linear dextrins (LD) and retain their characteristic helix amphiphilic cavities with flexible embedding capability, is a question worth exploring without adding new chemical groups. The strategy presented in this study is to attach a highly flexible (α-1 → 6) glucochain at the reducing end of LD by preparing a new type of dextrin, referred to as single-arm linear dextrin (SLD). In the actual synthesis, an (α-1 → 6) linked oligosaccharide of DP¯ 10.7 (PDI = 1.28) was formed by extension of glucose units onto sucrose (2 M) by using L940W mutant of the glucansucrase GTF180-ΔN firstly. Next using γ-CD as glucosylation donor γ-CGTase extended this (α-1 → 6) glucochain with (α-1 → 4) bonds. SLD is a chimeric glucosaccharide comprising an (α-1 → 4) linked part (DP¯ 10.5) attached to the nonreducing end of an (α-1 → 6) glucochain as verified by enzyme fingerprinting and ¹H NMR. Furthermore, SLD was validated to show greatly improved solubility and dispersibility of resveratrol in water, as indicated by a 3.12-fold enhancement over the solubility in the presence of 0.014 M SLD. This study provided a new strategy for solving the solubility problem of LD and opens possibilities for new design of the fine structure of starch-like materials.

Pullulan in pharmaceutical and cosmeceutical formulations: A review

Pullulan, an α-glucan polysaccharide, is colorless, odorless, non-toxic, non-carcinogenic, highly biocompatible, edible and biodegradable in nature. The long chains of glucopyranose rings in pullulan structure are linked together by α-(1 → 4) and α-(1 → 6) glycosidic linkages. The occurrence of both glycosidic linkages in the pullulan structure contributes to its distinctive properties. The unique structure of pullulan makes it a potent candidate for both pharmaceutical and cosmeceutical applications. In pharmaceuticals, it can be used as a drug carrier and in various dosage formulations. It has been widely used in drug targeting, implants, ocular dosage forms, topical formulations, oral dosage forms, and oral liquid formulations, etc. Pullulan can be used as a potential carrier of active ingredients and their site-specific delivery to skin layers for cosmeceutical applications. It has been extensively used in cosmeceutical formulations like creams, shampoo, lotions, sunscreen, facial packs, etc. The current review highlights applications of pullulan in pharmaceutical and cosmeceutical applications.

Folic acid-modified biocompatible Pullulan/poly(acrylic acid) nanogels for targeted delivery to MCF-7 cancer cells

We prepared a novel nanogel consisting of poly(acrylic acid) (PAA) and pullulan (Pull) via a facile and green irradiation protocol. Synthesized nanogels were modified with bovine serum albumin (BSA) and folic acid (FA) and then loaded with doxorubicin (DOX) to obtain a delivery system with tumor-specific targeting ability and enhanced biocompatibility. In-vitro DOX release was investigated at different pH values, and it was found that DOX release was higher in acidic media, which is an advantage for the internalization of nanoparticles in acidic tumor environment. MTT assay and DAPI staining were performed to evaluate the effects of nanogels on L929 and MCF-7 cells. Based on the results of in vitro studies, DOX-loaded nanogels were found to be effective on cancer cells, while the neat ones were nondestructive in both lines. Overall, we envision that the biocompatible and tumor-specific nanogels could be a promising safe drug carrier system for cancer therapy.

Exopolysaccharides of Fungal Origin: Properties and Pharmaceutical Applications

Fungal exopolysaccharides (EPSs) represent an important group of bioactive compounds secreted by fungi. These biopolymers can be utilized individually or in combination with different bioactive substances for a broad range of pharmaceutical field applications, due to their various biological activities, such as antioxidant, antimicrobial, anti-inflammatory, antiviral, anti-diabetic, and anticoagulant effects. The paper presents an up-to-date review of the main fungal polysaccharides (pullulan, schizophyllan, scleroglucan, botryosphaeran, lentinan, grifolan, and lasiodiplodan), highlighting their structures, producing strains, and useful properties in a double position, as controlled release (rate and selectively targeting) drug carriers, but mostly as active immunomodulating and antitumor compounds in cancer therapy.

M1 to M2 induction in macrophages using a retinoic acid-releasing mesenchymal stem cell scaffold

BACKGROUND

Modulation of macrophage polarization is required for effective tissue repair and regenerative therapies. Therapeutic modulation of macrophages from an inflammatory M1 to a fibrotic M2 phenotype could help in diseases, such as chronic wounds, which are stalled in a prolonged and heightened inflammatory stage within the wound healing process.

OBJECTIVE

This study evaluates the efficiency of a pullulan/gelatin nanofiber scaffold loaded with retinoic acid (RA) and adipose-derived mesenchymal stem cells (ASCs) to modulate M1 to M2 anti-inflammatory transition.

METHODS

Scaffolds were fabricated by electrospinning, and crosslinked using ethylene glycol diglycidyl ether (EGDE). Exposure of RA and/or ASCs to cultured macrophages have been shown to promote M1 to M2 transition. Pullulan was chosen as a scaffold material due to its ability to quench reactive oxygen species, key signaling molecules that play an important role in the progression of inflammation, as well as for its excellent mechanical properties. Gelatin was chosen as an additional scaffold component due to the presence of cell-binding motifs and its biocompatibility. Scaffold compositions examined were 75:25 and 50:50, pullulan:gelatin. The scaffolds were crosslinked in 1:70 and 1:50 EGDE:EtOH. The scaffold composition was determined via FTIR. For the present study, the 75:25 pullulan:gelatin crosslinked with 1:70 EGDE:EtOH, forming nanofibers 328 ± 47.9 nm (mean ± SD) in diameter, was chosen as the scaffold composition due to its lower degradation and release rate, which allows a sustained delivery of RA.

RESULTS

The scaffold composition degraded to approximately 80% after 14 days, with approximately 38% of the drug released after 7 days. THP-1 monocytic cells were induced into a M1 macrophage phenotype through stimulation with lipopolysaccharide (LPS) and gamma interferon (IFN-γ). These M1 macrophages were the exposed to scaffolds loaded with RA and ASCs, to induce differentiation to an M2 phenotype.

CONCLUSION

Gene expression quantitation by qPCR showed a reduction of M1 biomarkers, tumor necrosis factor alpha (TNFα) and interleukin 1β (IL1β), and an increase of M2 biomarker CCL22 after 2 days of exposure, suggesting successful M1 to M2 transition.

Preparation and evaluation of chitosan- and hyaluronic acid-grafted pullulan succinate films for skin wound healing

A novel wound dressing that possesses antibacterial properties and accelerates skin wound repair was developed by physically blending hyaluronic acid-grafted pullulan succinate (HA-st-Pu) with chitosan (CS). The HA-st-Pu polymer was synthesized and characterized, and then CS/HA-st-Pu film dressings were prepared by a freeze-drying method. The novel film wound dressings exhibited a three-dimensional cavity structure under scanning electron microscopy (SEM) and a better swelling ratio than CS, HA and Pu alone, absorbing a large amount of liquid and effectively maintaining the moist environment of the wound. CS/HA-st-Pu materials had no cytotoxicity and increased cell proliferation when coincubated with L929 cells. Moreover, CS/HA-st-Pu wound dressings exhibited a certain antibacterial capability against E. coli and S. aureus. In rat skin wound healing, CS/HA-st-Pu film dressings outperformed both the control and market band-aid groups with respect to the reduction of inflammation and acceleration of wound closure.

Polysaccharide-based hydrogels for drug delivery and wound management: a review

INTRODUCTION

Polysaccharide-based hydrogels (PBHs) offer several advantages over their synthetic counterparts. Their natural origin contributes to their nontoxicity, high biocompatibility, and in vivo biodegradability. Their properties can be tuned finely to obtain hydrogels with desired mechanical, structural, and chemical properties.

AREAS COVERED

Such versatile characteristics have potentiated the use of PBHs for the delivery of drugs, vaccines, protein and peptide therapeutics, genes, cells, probiotics, bacteriophages, and other therapeutic agents. Recent advances in hydrogel-based formulations such as nanogels, microgels, microneedles, hydrogel beads, nanocarrier-loaded hydrogels, and complexation hydrogels have enabled the precise delivery of a wide range of therapeutics. This review aims to give a holistic overview of hydrogels in the delivery of a variety of therapeutics through different routes.

EXPERT OPINION

PBHs have been used to enable the oral delivery of vaccines and other biologicals, thereby allowing self-administration of life-saving vaccines during public health emergencies. There is a lack of commercialized wound dressings for the treatment of chronic wounds. PBH-based wound dressings, especially those based on chitosan and loaded with actives and growth factors, have the potential to help in the long-term treatment of such wounds. Recent developments in the 3D printing of hydrogels can enable the quick and large-scale production of drug-loaded hydrogels.

Hemostatic Cryogels Based on Oxidized Pullulan/Dopamine with Potential Use as Wound Dressings

The impetus for research into hydrogels based on selectively oxidized polysaccharides has been stimulated by the diversity of potential biomedical applications. Towards the development of a hemostatic wound dressing in this study, we creatively combined the (hemi)acetal and Schiff base bonds to prepare a series of multifunctional cryogels based on dialdehyde pullulan and dopamine. The designed structures were verified by NMR and FTIR spectroscopy. Network parameters and dynamic sorption studies were correlated with environmental scanning microscopy results, thus confirming the successful integration of the two components and the opportunities for finely tuning the structure-properties balance. The viscoelastic parameters (storage and loss moduli, complex and apparent viscosities, zero shear viscosity, yield stress) and the structural recovery capacity after applying a large deformation were determined and discussed. The mechanical stability and hemostatic activity suggest that the optimal combination of selectively oxidized pullulan and dopamine can be a promising toolkit for wound management.

Sorafenib-Entrapped, Self-Assembled Pullulan–Stearic Acid Biopolymer-Derived Drug Delivery System to PLC/PRF/5 Hepatocellular Carcinoma Model

Purpose

This study aimed to design a prototypic drug delivery system (DDS) made of an amphiphilic, pullulan (Pull)-derived biodegradable polymer for targeting the asialoglycoprotein receptor (ASGPR) overexpressed in HCC. Stearic acid (SA) was conjugated to increase the hydrophobicity of pullulan (Pull-SA).

Methods

Pullulan (Pull) was linked to stearic acid (SA) after functional group modifications via EDC/NHS chemistry and characterized. Sorafenib tosylate (SRFT) was entrapped in pullulan–stearic acid nanoparticles (Pull-SA-SRFT) and its particle size, zeta potential, entrapment efficiency (EE), loading capacity (LC), and release efficiency was measured. The competence of Pull-SA-SRFT over SRFT in vitro was assessed using the ASGPR over-expressing PLC/PRF/5 hepatocellular carcinoma (HCC) cell line. This was done by studying cytotoxicity by MTT assay and chromosome condensation assay, early apoptosis by annexin-Pi staining, and late apoptosis by live–dead assay. The cellular uptake study was performed by incorporating coumarin-6 (C6) fluorophore in place of SRFT in Pull-SA conjugates. A biodistribution study was conducted in Swiss-albino mice to assess the biocompatibility and targeting properties of SRFT and Pull-SA-SRFT to the liver and other organs at 1, 6, 24, and 48 h.

Results

The characterization studies of the copolymer confirmed the successful conjugation of Pull-SA. The self-assembled amphiphilic nanocarrier could proficiently entrap the hydrophobic drug SRFT to obtain an entrapment efficiency of 95.6% (Pull-SA-SRFT). Characterization of the synthesized nanoparticles exhibited highly desirable nanoparticle characteristics. In vitro, apoptotic studies urged that Pull-SA-SRFT nanoparticle was delivered more efficiently to HCC than SRFT. The cellular uptake study performed, gave propitious results in 4 hrs. The biodistribution study conducted in immunocompetent mice suggested that Pull-SA-SRFT was delivered more than SRFT to the liver when compared to other organs, and that the system was biocompatible.

Conclusion

Pull-SA-SRFT is a promisingly safe, biodegradable, cell-specific nanocarrier and a potential candidate to target hydrophobic drugs to HCC.

Synthesis and characterization of modified bioactive arabinoxylan-psyllium: Evaluation of molecular interactions, physiochemical and biomedical properties

Keeping in view the future prospectus of carbohydrate polymers, present research report is an elaboration, exploration and execution of the research expectancy in area of these polymers by researchers like John F. Kennedy. Herein, molecular interactions and physiochemical properties of modified bioactive arabinoxylan-psyllium have been evaluated for drug delivery applications. Arabinoxylan-psyllium was modified with sulphated and amide copolymers and co-polymers were characterized by SEMs, AFM, FTIR, XRD, solid state ¹³C NMR, TGA-DSC and water absorption studies. The ¹³C-NMR and FTIR confirmed grafted copolymers. The polymer-blood interactions revealed non-thrombogenic nature with thrombose percentage 63.17 ± 5.61 % and polymer-mucous membrane interactions showed detachment force 0.237 ± 0.078Nwith bio-membrane in mucoadhesion test. The pH responsible gels exhibited 44.49 ± 3.12 % inhibitions of free radicals in DPPH assay. The polymer-drug interactions demonstrated sustained diffusion of methotrexate with non-Fickian diffusion and Korsmeyer-Peppas kinetic model. Overall, co-polymeric network structure was found useful in colon specific drug delivery.

Pullulan Oxidation in the Presence of Hydrogen Peroxide and N-Hydroxyphthalimide

The C-6 in the maltotriose unit of pullulan was oxidized in an alkaline medium (pH = 10), utilizing a green method that included hydrogen peroxide (H₂O₂) as an oxidant and N-hydroxyphthalimide (NHPI) as a catalyst for various reaction times. The structure of the resulting oxidized pullulans (PO) was carefully characterized by titration, intrinsic viscosity, FTIR, ¹³C-NMR, and zeta potential. The content of carboxyl groups in PO was dependent on reaction time and varied accordingly. Furthermore, a fast reaction rate was found in the first 2-3 h of the reaction, followed by a decreased rate in the subsequent hours. FTIR and ¹³C-NMR proved that the selective oxidation of the primary alcohol groups of pullulan was achieved. The oxidation also caused the glycoside linkages in the pullulan chain to break, and the viscosity of the pullulan itself went down.

Biopolymeric Prodrug Systems as Potential Antineoplastic Therapy

Nowadays, cancer represents a major public health issue, a substantial economic issue, and a burden for society. Limited by numerous disadvantages, conventional chemotherapy is being replaced by new strategies targeting tumor cells. In this context, therapies based on biopolymer prodrug systems represent a promising alternative for improving the pharmacokinetic and pharmacologic properties of drugs and reducing their toxicity. The polymer-directed enzyme prodrug therapy is based on tumor cell targeting and release of the drug using polymer–drug and polymer–enzyme conjugates. In addition, current trends are oriented towards natural sources. They are biocompatible, biodegradable, and represent a valuable and renewable source. Therefore, numerous antitumor molecules have been conjugated with natural polymers. The present manuscript highlights the latest research focused on polymer–drug conjugates containing natural polymers such as chitosan, hyaluronic acid, dextran, pullulan, silk fibroin, heparin, and polysaccharides from Auricularia auricula.

Placental cell translocation of folate-conjugated pullulan acetate non-spherical nanoparticles

Due to the adverse effects of free drugs on the fetus, placental-mediated pregnancy complications still lack effective pharmacotherapy. This study aims to construct a non-spherical drug delivery system based on folate-conjugated pullulan acetate (FPA) for placental targeting and translocation. By adjusting the initial solvent system, FPA nanoparticles with different morphologies were prepared using dialysis method without a surfactant. Cytotoxicity and lactate dehydrogenase release assays indicated the good biocompatibility of FPA nanoparticles in BeWo b30 cells. Cellular uptake and in vitro placental barrier transportation studies showed that FPA nanoparticles entered the cells and transported across the cell monolayer, benefiting from the active target effect mediated by the folate receptor. Moreover, non-spherical FPA nanoparticles showed nuclear translocation due to their shape effect. These findings provide a novel aspect in placental-mediated pregnancy treatment and applications in the obstetrics field of drug use during pregnancy.

A review on plant polysaccharide based on drug delivery system for construction and application, with emphasis on traditional Chinese medicine polysaccharide

Carbohydrate polymers with unique chemical composition, molecular weight and functional chemical groups show multiple potentials in drug delivery. Most carbohydrate polymers such as plant polysaccharides exhibit advantages of biodegradability, ease of modification, low immunogenicity and low toxicity. They can be conjugated, cross-linked or functionally modified, and then used as nanocarrier materials. Polysaccharide drug delivery system can avoid the phagocytosis of the reticuloendothelial system, prevent the degradation of biomolecules, and increase the bioavailability of small molecules, thus exerting effective therapeutic effects. Therefore, they have been fully explored. In this paper, we reviewed the construction methods of drug delivery systems based on carbohydrate polymers (astragalus polysaccharide, angelica polysaccharide, lycium barbarum polysaccharide, ganoderma lucidum polysaccharide, bletilla polysaccharide, glycyrrhiza polysaccharide, and epimedium polysaccharides, etc). The application of polysaccharide drug delivery systems to deliver small molecule chemotherapeutic drugs, gene drugs, and metal ion drugs was also briefly introduced. At the same time, the role of the polysaccharide drug delivery system in tumor treatment, targeted therapy, and wound healing was discussed. In addition, the research of polysaccharide delivery systems based on the therapeutic efficacy of traditional Chinese medicine was also summarized and prospected.

Downstream processing and structural confirmation of pullulan - A comprehensive review

Pullulan is a microbial polymer, commercially produced from Aureobasidium pullulans. Downstream processing of pullulan involves a multi-stage process which should be efficient, safe and reproducible. In liquid-liquid separations, firstly cell free extract is separated. Cell biomass can be separated after fermentation either by centrifugation or filtration. Due to practically insolubility of pullulan in organic solvents, ethanol and isopropanol are the most commonly used organic solvents for its recovery. Pullulan can also be purified by chromatographic techniques, but these are not cost effective for the purification of pullulan. Efficient aqueous two-phase system can be used for the purification of pullulan. The current review describes the methods and perspectives used for solid-liquid separation, liquid-liquid separations and finishing steps for the recovery of pullulan. Techniques used to determine the structural attributes of pullulan have also been highlighted.

Addressing the Needs of the Rapidly Aging Society through the Development of Multifunctional Bioactive Coatings for Orthopedic Applications

The unprecedented aging of the world's population will boost the need for orthopedic implants and expose their current limitations to a greater extent due to the medical complexity of elderly patients and longer indwelling times of the implanted materials. Biocompatible metals with multifunctional bioactive coatings promise to provide the means for the controlled and tailorable release of different medications for patient-specific treatment while prolonging the material's lifespan and thus improving the surgical outcome. The objective of this work is to provide a review of several groups of biocompatible materials that might be utilized as constituents for the development of multifunctional bioactive coatings on metal materials with a focus on antimicrobial, pain-relieving, and anticoagulant properties. Moreover, the review presents a summary of medications used in clinical settings, the disadvantages of the commercially available products, and insight into the latest development strategies. For a more successful translation of such research into clinical practice, extensive knowledge of the chemical interactions between the components and a detailed understanding of the properties and mechanisms of biological matter are required. Moreover, the cost-efficiency of the surface treatment should be considered in the development process.

Polysaccharide-Drug Conjugates: A Tool for Enhanced Cancer Therapy

Cancer is one of the most widespread deadly diseases, following cardiovascular disease, worldwide. Chemotherapy is widely used in combination with surgery, hormone and radiation therapy to treat various cancers. However, chemotherapeutic drugs can cause severe side effects due to non-specific targeting, poor bioavailability, low therapeutic indices, and high dose requirements. Several drug carriers successfully overcome these issues and deliver drugs to the desired sites, reducing the side effects. Among various drug delivery systems, polysaccharide-based carriers that target only the cancer cells have been developed to overcome the toxicity of chemotherapeutics. Polysaccharides are non-toxic, biodegradable, hydrophilic biopolymers that can be easily modified chemically to improve the bioavailability and stability for delivering therapeutics into cancer tissues. Different polysaccharides, such as chitosan, alginates, cyclodextrin, pullulan, hyaluronic acid, dextran, guar gum, pectin, and cellulose, have been used in anti-cancer drug delivery systems. This review highlights the recent progress made in polysaccharides-based drug carriers in anti-cancer therapy.