Cyclodextrin regulated natural polysaccharide hydrogels for biomedical applications-a review

Advances in polysaccharide-based materials for biomedical and pharmaceutical applications: A comprehensive review

Polysaccharides, the most abundant biopolymers in nature, have attracted the attention of researchers and clinicians due to its practicality in biomedical and pharmaceutical sciences. These biomaterials have high bioavailability and play structural and functional roles in living organisms. Polysaccharides are classified into several groups based on their origin, including plant polysaccharides and marine polysaccharides (like chitosan, hyaluronic acid, dextran, alginates, etc.) with specific applications. These biopolymers possess unique physicochemical (such as surface functional groups, solubility, and stability), mechanical (like mechanical strength and tensile), and biomedical (such as antioxidant activity, biocompatibility, biodegradability, renewability, and non-immunogenicity) characteristics which have made them excellent platforms for a wide variety of biomedical and pharmaceutical applications. Ease of extraction and different preparation approaches are mentioned as other potential properties of polysaccharides that further improved their practicality in biomedical sciences. They have high drug/bioactive encapsulation capacity and sustained/controlled release manner in in vivo microenvironments. The anti-inflammatory and immunomodulation, stimuli-responsive drug/bioactive release, and passive and active drug/bioactive delivery are considered the potential features of these biopolymers in pharmaceutical sciences. Polysaccharides have indicated practical applications in biomedical sciences, including biosensors, tissue engineering, implantation, wound healing, vascular grafting, and vaccines. This review highlights the advances of polysaccharide-based materials in biomedical and pharmaceutical sciences.

Enhancement of gel characteristics of curdlan thermo-irreversible gels by β-cyclodextrin and its possible mechanisms

In this study, the influences of various concentrations of β-cyclodextrin (β-CD) on the gelation properties of curdlan thermo-irreversible gels were evaluated. The results revealed that water-holding capacity and freeze-thaw stability of the curdlan/β-CD complex gels initially increased but then decreased with increasing β-CD concentration, with the curdlan gel containing 1 % (w/v) β-CD demonstrating the best performance. Moreover, textural characteristics including hardness, gumminess, cohesiveness, and chewiness exhibited similar trends, but springiness showed minor effect. Compared with the pure curdlan gel, the curdlan/β-CD mixed gels exhibited better elastic behavior and greater thermal stability but lower crystallinity. Additionally, scanning electron microscopy (SEM) images of the curdlan/β-CD composite gels revealed fine network structures with relatively continuous pores. The intermolecular hydrogen bonds between curdlan and β-CD were responsible for the enhanced gel properties. Thus, these data suggest that the inclusion of β-CD ameliorates the texture and stability of the curdlan gel by forming hydrogen bonds.

Tetraphenylborate enhanced enzymatic production of γ-cyclodextrin: System construction and its mechanism

γ-Cyclodextrin (γ-CD) is an attractive material among the natural cyclodextrins owing to its excellent properties. γ-CD is primarily produced from starch by γ-cyclodextrin glycosyltransferase (γ-CGTase) in a controlled system. However, difficulty in separation and low conversion rate leads to high production costs for γ-CD. In this study, γ-CGTase from Bacillus sp. G-825-6 STB17 was used in γ-CD production from cassava starch. With the introduction of sodium tetraphenylborate (NaBPh4), the total conversion rate was promoted from an initial 18.07 % to 50.49 % and the γ-CD ratio reached 78.81 % with a yield of 39.79 g/L. Furthermore, the mechanism was conducted via the determination of binding constant, which indicated that γ-CD exhibited much stronger binding strength with NaBPh4 than β-CD. The reformation of water molecules and the chaotropic effect might be the main driving forces for the interaction. Additionally, the conformations of CD complexes were depicted by NMR and molecular docking. The results further verified different binding patterns between CDs and tetraphenylborate ions, which might be the primary reason for the specific binding. This system not only guides γ-CD production with an efficient and easy-to-remove production aid but also offers a new perspective on the selection of complexing agents in CD production.

A multifunctional and tough lotus root starch-based bio-photonic hydrogel for stretchable fabric pattern color change and water rewriting

Photonic crystal hydrogels (PCHs) are innovative materials that translate imperceptible deformations and humidity changes into visible colors, broadening the applications of photonics in bioengineering and smart materials. To overcome poor mechanical properties of traditional PCHs limited by weak intermolecular forces, we designed a PCH with a dual-network framework comprising N-isopropylacrylamide-co-acrylamide (NIPAM-co-AM) and biomass lotus root starch (LR). Since LR is rich in hydroxyl groups, it can undergo molecular linkage entanglement with the NIPAM-co-AM hydrogel matrix, forming hydrogen bonds that significantly enhance the mechanical properties of the PCH. We have prepared PCH films capable of conveying multidimensional information about the extent and distribution of transient deformation by encapsulating magnetic photonic crystal microspheres (MPCMs) within a hydrogel matrix. The PCH films were found to have ultrafast response time (< 10 s), full-color tunable range, high spatial resolution, excellent mechanical toughness (tensile up to 0.17 MPa) and sensitivity (2.52 nm %-1), and were able to sense relative humidity (RH) from 11 % to 98 %. Equipped with a dynamically reconfigurable lattice, this dual-responsive (tensile/humidity) PCH not only facilitates the creation of water-rewritable photonic films but also holds promise for integration into structural color elastic fabrics, thereby presenting novel prospects for smart textile applications.

Delivery Strategies of siRNA Therapeutics for Hair Loss Therapy

Therapeutic needs for hair loss are intended to find small interfering ribonucleic acid (siRNA) therapeutics for breakthrough. Since naked siRNA is restricted to meet a druggable target in clinic,, delivery systems are indispensable to overcome intrinsic and pathophysiological barriers, enhancing targetability and persistency to ensure safety, efficacy, and effectiveness. Diverse carriers repurposed from small molecules to siRNA can be systematically or locally employed in hair loss therapy, followed by the adoption of new compositions associated with structural and environmental modification. The siRNA delivery systems have been extensively studied via conjugation or nanoparticle formulation to improve their fate in vitro and in vivo. In this review, we introduce clinically tunable siRNA delivery systems for hair loss based on design principles, after analyzing clinical trials in hair loss and currently approved siRNA therapeutics. We further discuss a strategic research framework for optimized siRNA delivery in hair loss from the scientific perspective of clinical translation.

Continuous and Controllable Preparation of Sodium Alginate Hydrogel Tubes Guided by the Soft Cap Inspired by the Apical Growth of the Plant

Hydrogel tubes made of sodium alginate (SA) have potential applications in drug delivery, soft robots, biomimetic blood vessels, tissue stents, and other fields. However, the continuous preparation of hollow SA hydrogel tubes with good stability and size control remains a huge challenge for chemists, material scientists, and medical practitioners. Inspired by the plant apical growth strategy, a new method named soft cap-guided growth was proposed to produce SA hydrogel tubes. Due to the introduction of inert low gravity substances, such as air and heptane, into the extrusion needle in front of calcium chloride solution to form a soft cap, the SA hydrogel tubes with controllable sizes were fabricated rapidly and continuously without using a template through a negative gravitropism mechanism. The SA hydrogel tubes had good tensile strength, high burst pressure, and good cell compatibility. In addition, hydrogel tubes with complex patterns were conveniently created by controlling the motion path of a soft cap, such as a rotating SA bath or magnetic force. Our research provided a simple innovative technique to steer the growth of hydrogel tubes, which made it possible to mass produce hydrogel tubes with controllable sizes and programmable patterns.

Self-Assembled Nanocarrier Delivery Systems for Bioactive Compounds

Although bioactive compounds (BCs) have many important functions, their applications are greatly limited due to their own defects. The development of nanocarriers (NCs) technology has gradually overcome the defects of BCs. NCs are equally important as BCs to some extent. Self-assembly (SA) methods to build NCs have many advantages than chemical methods, and SA has significant impact on the structure and function of NCs. However, the relationship among SA mechanism, structure, and function has not been given enough attention. Therefore, from the perspective of bottom-up building mechanism, the concept of SA-structure-function of NCs is emphasized to promote the development of SA-based NCs. First, the conditions and forces for occurring SA are introduced, and then the SA basis and molecular mechanism of protein, polysaccharide, and lipid are summarized. Then, varieties of the structures formed based on SA are introduced in detail. Finally, facing the defects of BCs and how to be well solved by NCs are also elaborated. This review attempts to describe the great significance of constructing artificial NCs to deliver BCs from the aspects of SA-structure-function, so as to promote the development of SA-based NCs and the wide application of BCs.

Genetic and enzymatic characterization of Amy13E from Cellvibrio japonicus reclassifies it as a cyclodextrinase also capable of α-diglucoside degradation

Cyclodextrinases are carbohydrate-active enzymes involved in the linearization of circular amylose oligosaccharides. Primarily thought to function as part of starch metabolism, there have been previous reports of bacterial cyclodextrinases also having additional enzymatic activities on linear malto-oligosaccharides. This substrate class also includes environmentally rare α-diglucosides such as kojibiose (α-1,2), nigerose (α-1,3), and isomaltose (α-1,6), all of which have valuable properties as prebiotics or low-glycemic index sweeteners. Previous genome sequencing of three Cellvibrio japonicus strains adapted to utilize these α-diglucosides identified multiple, but uncharacterized, mutations in each strain. One of the mutations identified was in the amy13E gene, which was annotated to encode a neopullulanase. In this report, we functionally characterized this gene and determined that it in fact encodes a cyclodextrinase with additional activities on α-diglucosides. Deletion analysis of amy13E found that this gene was essential for kojibiose and isomaltose metabolism in C. japonicus. Interestingly, a Δamy13E mutant was not deficient for cyclodextrin or pullulan utilization in C. japonicus; however, heterologous expression of the gene in E. coli was sufficient for cyclodextrin-dependent growth. Biochemical analyses found that CjAmy13E cleaved multiple substrates but preferred cyclodextrins and maltose, but had no activity on pullulan. Our characterization of the CjAmy13E cyclodextrinase is useful for refining functional enzyme predictions in related bacteria and for engineering enzymes for biotechnology or biomedical applications.IMPORTANCEUnderstanding the bacterial metabolism of cyclodextrins and rare α-diglucosides is increasingly important, as these sugars are becoming prevalent in the foods, supplements, and medicines humans consume that subsequently feed the human gut microbiome. Our analysis of a cyclomaltodextrinase with an expanded substrate range is significant because it broadens the potential applications of the GH13 family of carbohydrate active enzymes (CAZymes) in biotechnology and biomedicine. Specifically, this study provides a workflow for the discovery and characterization of novel activities in bacteria that possess a high number of CAZymes that otherwise would be missed due to complications with functional redundancy. Furthermore, this study provides a model from which predictions can be made why certain bacteria in crowded niches are able to robustly utilize rare carbon sources, possibly to gain a competitive growth advantage.

Recent advances in biopolymer-based hydrogels and their potential biomedical applications

Hydrogels are three-dimensional networks of polymer chains containing large amounts of water in their structure. Hydrogels have received significant attention in biomedical applications owing to their attractive physicochemical properties, including flexibility, softness, biodegradability, and biocompatibility. Different natural and synthetic polymers have been intensely explored in developing hydrogels for the desired applications. Biopolymers-based hydrogels have advantages over synthetic polymers regarding improved cellular activity and weak immune response. These properties can be further improved by grafting with other polymers or adding nanomaterials, and they structurally mimic the living tissue environments, which opens their broad applicability. The hydrogels can be physically or chemically cross-linked depending on the structure. The use of different biopolymers-based hydrogels in biomedical applications has been reviewed and discussed earlier. However, no report is still available to comprehensively introduce the synthesis, advantages, disadvantages, and biomedical applications of biopolymers-based hydrogels from the material point of view. Herein, we systematically overview different synthesis methods of hydrogels and provide a holistic approach to biopolymers-based hydrogels for biomedical applications, especially in bone regeneration, wound healing, drug delivery, bioimaging, and therapy. The current challenges and prospects of biopolymers-based hydrogels are highlighted rationally, giving an insight into the progress of these hydrogels and their practical applications.

Dispersion-corrected DFT calculations and umbrella sampling simulations to investigate stability of Chrysin-cyclodextrin inclusion complexes

The study of inclusion complexes of Chrysin (ChR) with three forms of cyclodextrins (CDs) α-, β-, and γ-CD was accomplished to examine the stability of ChR inside the central cavities of CDs. The aim of study was to identify the most suitable form of CD to improve the hydro-solubility of poorly soluble ChR bioactive molecule. Microsecond timescale molecular dynamics (MD) simulations were performed on four inclusion complexes (α-CD/ChR, β-CD/ChR, and two conformations of γ-CD/ChR) to examine the dynamics of ChR inside the cavity of CDs. The first conformation of γ-CD/ChR inclusion complex (γ-CD1/ChR) was identified to possess the highest affinity between host and guest molecule on the basis of binding energy calculated by employing Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) and umbrella sampling simulations. To further strengthen the claims of classical and biased MD studies, Our own N-layered Integrated molecular Orbital and Molecular mechanics (ONIOM) (wB97XD/6-311+g(d,p):pm7) calculations were performed on the selected inclusion complexes. The ONIOM based complexation energy reaffirmed that ChR had highest affinity for the γ-CD1 host molecule. Further, the non-covalent interaction analysis was conducted using Multiwfn software on QM-optimized inclusion complexes with wB97XD/6-311+G(d,p) model chemistry, revealing non-covalent interactions between ChR and CDs. This atomic level information helped us to gain better insights into critical atoms of ChR and CD that participated in intermolecular interactions and identify γ-CD as a suitable host molecule for improving the hydro-solubulity of ChR. The structural insights would help to derive new derivatives of γ-CD with better host capacity.

Biological Activities and Solubilization Methodologies of Naringin

Naringin (NG), a natural flavanone glycoside, possesses a multitude of pharmacological properties, encompassing anti-inflammatory, sedative, antioxidant, anticancer, anti-osteoporosis, and lipid-lowering functions, and serves as a facilitator for the absorption of other drugs. Despite these powerful qualities, NG's limited solubility and bioavailability primarily undermine its therapeutic potential. Consequently, innovative solubilization methodologies have received considerable attention, propelling a surge of scholarly investigation in this arena. Among the most promising solutions is the enhancement of NG's solubility and physiological activity without compromising its inherent active structure, therefore enabling the formulation of non-toxic and benign human body preparations. This article delivers a comprehensive overview of NG and its physiological activities, particularly emphasizing the impacts of structural modification, solid dispersions (SDs), inclusion compound, polymeric micelle, liposomes, and nanoparticles on NG solubilization. By synthesizing current research, this research elucidates the bioavailability of NG, broadens its clinical applicability, and paves the way for further exploration and expansion of its application spectrum.