A platform for functionalization of cellulose, chitin/chitosan, alginate with polydopamine: A review on fundamentals and technical applications

Spectroscopic investigation, dielectric and antimicrobial properties of chitin-cellulose@ZnO/CuO conductive nanocomposites

In this research, we fabricated a functional conductive nanocomposite with valuable properties through a chitin (CH) and cellulose (CE) polymerization process, incorporating ZnO/(0.1, 0.2, 0.3 mol.%) CuO bioactive nanoparticles. These bioactive nanoparticles, synthesized through sol-gel and polymerization interactions, greatly enhanced the structural, dielectric, and antimicrobial characteristics of CH-CE@ZnO/CuO conductive nanocomposites. The morphological analysis revealed that these nanoparticles, with diameters ranging from 11-25 nm, formed covalent bonds with the membrane matrix, bolstering the conductive nanocomposites ' structural integrity and dielectric performance. The dielectric properties of the conductive nanocomposites were significantly enhanced by the even distribution of ZnO/CuO nanoparticles within the CH-CE composite. Additionally, antimicrobial assessments demonstrated that the CH-CE@ZnO/CuO conductive nanocomposites displayed significant antibacterial properties against the Escherichia coli and Staphylococcus aureus, showcasing their potential as active packaging materials for electronic, biosensors, and sustainable applications.

Hydrogel coating containing heparin and cyclodextrin/paclitaxel inclusion complex for retrievable vena cava filter towards high biocompatibility and easy removal

Aiming to improve the retrieval rate of retrievable vena cava filters (RVCF) and extend its dwelling time in vivo, a novel hydrogel coating loaded with 10 mg/mL heparin and 30 mg/mL cyclodextrin/paclitaxel (PTX) inclusion complex (IC) was prepared. The drug-release behavior in the phosphate buffer solution demonstrated both heparin and PTX could be sustainably released over approximately two weeks. Furthermore, it was shown that the hydrogel-coated RVCF (HRVCF) with 10 mg/mL heparin and 30 mg/mL PTX IC effectively extended the blood clotting time to above the detection limit and inhibited EA.hy926 and CCC-SMC-1 cells' proliferation in vitro compared to the commercially available bare RVCF. Both the HRVCF and the bare RVCF were implanted into the vena cava of sheep and retrieved at at 2nd and 4th week after implantation, revealing that the HRVCF had a significantly higher retrieval rate of 67 % than the bare RVCF (0 %) at 4th week. Comprehensive analyses, including histological, immunohistological, and immunofluorescent assessments of the explanted veins demonstrated the HRVCF exhibited anti-hyperplasia and anticoagulation properties in vivo, attributable to the hydrogel coating, thereby improving the retrieval rate in sheep. Consequently, the as-prepared HRVCF shows promising potential for clinical application to enhance the retrieval rates of RVCFs.

Fabrication and characterization of polydopamine-mediated zein-based nanoparticle for delivery of bioactive molecules

In this study, a combination of whey protein (hydrophilic coating) and polydopamine (crosslinking agent) was used to improve the stability and functionality of quercetin-loaded zein nanoparticles. There are two key benefits of the core-shell nanoparticles formed. First, the ability of the polydopamine to bind to both zein and whey protein facilitates the formation of a stable core-shell structure, thereby protecting quercetin from any pro-oxidants in the aqueous surroundings. Second, neutral and hydrophilic whey proteins were used for the surface coating of the nanoparticles to further enhance the sustained and slow release of quercetin, facilitating its sustained release into the body at a slow and steady rate. The results of this study will promote the innovative development of precise nutritional delivery systems for zein and provide a theoretical basis for the design and development of dietary supplements based on hydrophobic food nutrient molecules.

Miniaturized 3D-printed hand-operable dispersive sample pretreatment device with replaceable chitosan/polydopamine thin film metal sorbent for enhanced metal analysis

To address the increasing demand for sensitive and selective sample preparation methods for metal analysis; preconcentration of intended analyte from complex sample matrices before analysis is required to improve the performance of analysis instruments. In this study, we have engineered a sustainable and portable syringe-based hand-operable three-dimensionally (3D) printed sample pretreatment apparatus equipped with a replaceable bio-based thin- film metal sorbent. This device effectively addresses the challenges of sample matrix interference in metal analysis. A metal sorbent film composed of chitosan (CS) and polydopamine (PDA) leveraged the diverse functional groups in the CS/PDA matrix to significantly enhance the extraction efficiency for various metals. Our approach demonstrated excellent analytical performance, with coefficients of determination (R2) of 0.9982 for copper (Cu) and 0.996 for chromium (Cr). The method achieved low limits of detection (LOD) of 0.3 μg L-1 for Cr and 0.7 μg L-1 for Cu. Precision and practicality assessments using actual urine samples yielded satisfactory relative standard deviations (RSD%) ranging from of 1.6 %-8.5 % for both metals, indicating minimal interference from the sample matrix. Moreover, our approach exhibited robust performance even after seven consecutive extraction and desorption cycles, highlighting its sustainability and practical applicability for laboratory and on-site sample pretreatment.

Polydopamine-armored zeolitic imidazolate framework-8-incorporated zwitterionic hydrogel with multifunctional properties for infected wound healing

Diabetic skin wound healing is compromised by bacterial infections, oxidative stress, and vascular disruption, leading to delayed recovery and potential complications. This study developed an antibacterial, antioxidant, and adhesive hydrogel dressing that promotes rapid bacterial-infected diabetic wound healing using the biological macromolecule of polydopamine (PDA). This hydrogel comprised PDA-armored zeolitic imidazolate framework-8 nanoparticles (PDA@ZIF-8 NPs) combined with a second armor of zwitterionic polymer network (poly(acrylamide-co-sulfobetaine methacrylate); PAS), realizing low concentration Zn2+ release, good adhesion (14.7 kPa for porcine skin), and improved tensile strength (83.2 kPa). The hydrogel exhibited good antibacterial efficacy against both Staphylococcus aureus (S. aureus, 92.8 %), Escherichia coli (E. coli, 99.6 %) and methicillin-resistant S. aureus (MRSA, 99.2 %), which was attributed to the properties of the incorporated PDA@ZIF-8 NPs. Notably, in vitro, the PDA@ZIF-8 PAS hydrogel not only promoted fibroblast proliferation and migration but also facilitated endothelial cell angiogenesis. In vivo, the PDA@ZIF-8 PAS hydrogel retained its Zn2+-releasing function and effectively suppressed bacterial growth in infected wounds, thereby accelerating the regeneration of both normal and diabetic wounds. This multiarmored hydrogel is a promising sustained-release carrier for functional metal ions and drugs, making it applicable for not only skin healing, but potentially the regeneration of other complex tissues.

A Novel Bio-Adhesive Based on Chitosan-Polydopamine-Xanthan Gum for Glass, Cardboard and Textile Commodities

The escalating environmental concerns associated with petroleum-based adhesives have spurred an urgent need for sustainable alternatives. Chitosan, a natural polysaccharide, is a promising candidate; however, its limited water resistance hinders broader application. The aim of this study is to develop a new chitosan-based adhesive with improved properties. The polydopamine association with chitosan presents a significant increase in adhesiveness compared to pure chitosan. Polydopamine is synthesized by the enzymatic action of laccase from Trametes versicolor at pH = 4.5, in the absence or presence of chitosan. This pH facilitates chitosan's solubility and the occurrence of catechol in its reduced form (pH < 5.5), thereby increasing the final adhesive properties. To further enhance the adhesive properties, various crosslinking agents were tested. A multi-technique approach was used for the characterization of formulations. The formulation based on 3% chitosan, 50% polydopamine, and 3% xanthan gum showed a spectacular increase in adhesive properties when tested on glass, cardboard and textile. This formulation increased water resistance, maintaining the adhesion of a sample soaked in water for up to 10 h. For cardboard and textile, material rapture occurred, in mechanical tests, prior to adhesive bond failure. Furthermore, all the samples showed antiflame properties, expanding the benefits of their use. Comparison with commercial glues confirms the remarkable adhesive properties of the new formulation.

A review of cellulose-based catechol-containing functional materials for advanced applications

With the increment in global energy consumption and severe environmental pollution, it is urgently needed to explore green and sustainable materials. Inspired by nature, catechol groups in mussel adhesion proteins have been successively understood and utilized as novel biomimetic materials. In parallel, cellulose presents a wide class of functional materials rating from macro-scale to nano-scale components. The cross-over among both research fields alters the introduction of impressive materials with potential engineering properties, where catechol-containing materials supply a general stage for the functionalization of cellulose or cellulose derivatives. In this review, the role of catechol groups in the modification of cellulose and cellulose derivatives is discussed. A broad variety of advanced applications of cellulose-based catechol-containing materials, including adhesives, hydrogels, aerogels, membranes, textiles, pulp and papermaking, composites, are presented. Furthermore, some critical remaining challenges and opportunities are studied to mount the way toward the rational purpose and applications of cellulose-based catechol-containing materials.

Anisotropic materials based on carbohydrate polymers: A review of fabrication strategies, properties, and applications

Anisotropic structures exist in almost all living organisms to endow them with superior properties and physiological functionalities. However, conventional artificial materials possess unordered isotropic structures, resulting in limited functions and applications. The development of anisotropic structures on carbohydrates is reported to have an impact on their properties and applications. In this review, various alignment strategies for carbohydrates (i.e., cellulose, chitin and alginate) from bottom-up to top-down strategies are discussed, including the rapidly developed innovative technologies such as shear-induced orientation through extrusion-based 3D/4D printing, magnetic-assisted alignment, and electric-induced alignment. The unique properties and wide applications of anisotropic carbohydrate materials across different fields, from biomedical, biosensors, smart actuators, soft conductive materials, to thermal management are also summarized. Finally, recommendations on the selection of fabrication strategies are given. The major challenge lies in the construction of long-range hierarchical alignment with high orientation degree and precise control over complicated architectures. With the future development of hierarchical alignment strategies, alignment control techniques, and alignment mechanism elucidation, the potential of anisotropic carbohydrate materials for scalable manufacture and clinical applications will be fully realized.

Emerging natural polymer-based architectured nanotherapeutics for the treatment of cancer

The field of cancer therapy is advancing rapidly, placing a crucial emphasis on innovative drug delivery systems. The increasing global impact of cancer highlights the need for creative therapeutic strategies. Natural polymer-based nanotherapeutics have emerged as a captivating avenue in this pursuit, drawing substantial attention due to their inherent attributes. These attributes include biodegradability, biocompatibility, negligible toxicity, extended circulation time, and a wide range of therapeutic payloads. The unique size, shape, and morphological characteristics of these systems facilitate profound tissue penetration, complementing active and passive targeting strategies. Moreover, these nanotherapeutics exploit specific cellular and subcellular trafficking pathways, providing precise control over drug release kinetics. This comprehensive review emphasizes the utilization of naturally occurring polymers such as polysaccharides (e.g., chitosan, hyaluronic acid, alginates, dextran, and cyclodextrin) and protein-based polymers (e.g., ferritin, gelatin, albumin) as the foundation for nanoparticle development. The paper meticulously examines their in vitro characteristics alongside in vivo efficacy, particularly focusing on their pivotal role in ameliorating diverse types of solid tumors within cancer therapy. The amalgamation of material science ingenuity and biological insight has led to the formulation of these nanoparticles, showcasing their potential to reshape the landscape of cancer treatment.

Current application and modification strategy of marine polysaccharides in tissue regeneration: A review

Marine polysaccharides (MPs) are exceptional bioactive materials that possess unique biochemical mechanisms and pharmacological stability, making them ideal for various tissue engineering applications. Certain MPs, including agarose, alginate, carrageenan, chitosan, and glucan have been successfully employed as biological scaffolds in animal studies. As carriers of signaling molecules, scaffolds can enhance the adhesion, growth, and differentiation of somatic cells, thereby significantly improving the tissue regeneration process. However, the biological benefits of pure MPs composite scaffold are limited. Therefore, physical, chemical, enzyme modification and other methods are employed to expand its efficacy. Chemically, the structural properties of MPs scaffolds can be altered through modifications to functional groups or molecular weight reduction, thereby enhancing their biological activities. Physically, MPs hydrogels and sponges emulate the natural extracellular matrix, creating a more conducive environment for tissue repair. The porosity and high permeability of MPs membranes and nanomaterials expedite wound healing. This review explores the distinctive properties and applications of select MPs in tissue regeneration, highlighting their structural versatility and biological applicability. Additionally, we provide a brief overview of common modification strategies employed for MP scaffolds. In conclusion, MPs have significant potential and are expected to be a novel regenerative material for tissue engineering.

Cellulose-based adsorbents for solid phase extraction and recovery of pharmaceutical residues from water

Cellulose has attracted interest from researchers both in academic and industrial sectors due to its unique structural and physicochemical properties. The ease of surface modification of cellulose by the integration of nanomaterials, magnetic components, metal organic frameworks and polymers has made them a promising adsorbent for solid phase extraction of emerging contaminants, including pharmaceutical residues. This review summarizes, compares, and contrasts different types of cellulose-based adsorbents along with their applications in adsorption, extraction and pre-concentration of pharmaceutical residues in water for subsequent analysis. In addition, a comparison in efficiency of cellulose-based adsorbents and other types of adsorbents that have been used for the extraction of pharmaceuticals in water is presented. From our observation, cellulose-based materials have principally been investigated for the adsorption of pharmaceuticals in water. However, this review aims to shift the focus of researchers to the application of these adsorbents in the effective pre-concentration of pharmaceutical pollutants from water at trace concentrations, for quantification. At the end of the review, the challenges and future perspectives regarding cellulose-based adsorbents are discussed, thus providing an in-depth overview of the current state of the art in cellulose hybrid adsorbents for extraction of pharmaceuticals from water. This is expected to inspire the development of solid phase exraction materials that are efficient, relatively cheap, and prepared in a sustainable way.

Mussel-inspired laccase-mediated polydopamine graft onto bamboo fibers and its improvement effect on poly(3-hydroxybutyrate) based biocomposite

Bamboo fiber (BF) reinforced polyhydroxybutyrate (PHB) has become popular in developing an eco-friendly and sustainable biocomposite, while the weak interfacial compatibility between them is a major problem to overcome. This work, inspired by mussel super adhesion, creates a facile, highly efficient, and environmentally friendly solution based on in situ laccase-catalysed dopamine polymerization under a naturally acidic environment. The result indicates that a stabilized polydopamine coating is successfully grafted onto the lignin of BF, and it also enhances the thermal stability of the BF and biocomposite. Furthermore, modification of BF via laccase-catalysed polydopamine is superior to the conventional method of polydopamine under alkaline condition, and has outstanding advantages in terms of BF integrity protection. The optimal composition of biocomposite with BF treated by polydopamine under 1 U/ml concentration of laccase shows improvement in the impact strength, tensile strength, tensile modulus, bending strength, and modulus of elastic by 33.85 %, 9.27 %, 31.74 %, 11.76 %, and 12.92 %, respectively, compared to the unmodified counterpart. This work provides an insightful understanding of the mechanism and benefits of laccase-catalysed polydopamine modification of BF in a natural environment. It contributes to the efficient and environmentally friendly utilization of polydopamine for fabricating high-performance lignocellulosic fiber reinforced biocomposites.

Synthesis and characterization of mussel-inspired nanocomposites based on dopamine-chitosan-iron oxide for wound healing: In vitro study

There are many challenges faced the soft tissue adhesives in the medical application field. For example, there is a limited effective binding between the medical adhesive and different types of soft tissues. Chitosan (CS) and dopamine (DA) were used as structural units for synthesizing nanocomposites utilized as a wet tissue adhesive. To produce dopamine-chitosan-iron oxide nanocomposites (DA-CS-Fe₃O₄ NCs), DA was loaded onto chitosan-iron oxide nanocomposites. The nanocomposites have been prepared using ionic gelation method under vigorous homogenization and characterized by different techniques. Fourier-transform infrared spectroscopy (FTIR) have shown that DA-CS- Fe₃O₄ NCs could attach to the tissue through two possible functional groups, namely, the catechol and amine groups. The results of in vitro scratch wound-healing assay suggested that the prepared DA-CS- Fe₃O₄ NCs facilitate cell migration (the wound-closure percentage reached 96% at 72 h). All experimental results confirm that DA-CS- Fe₃O₄ NCs are strongly recommended for use as a soft medical tissue adhesive in wound healing and surgeries such as vascular surgery. In addition, the results of the whole blood clotting, antibacterial assessment, live and dead assay, cytotoxicity test, and wound-healing assay indicate that DA-CS-Fe₃O₄ NCs can be used as a multifunctional biomedical adhesive.

Mussel-Based Biomimetic Strategies in Musculoskeletal Disorder Treatment: From Synthesis Principles to Diverse Applications

Musculoskeletal disorders are the second leading cause of disability worldwide, posing a huge global burden to the public sanitation system. Currently, tissue engineering-based approaches act as effective strategies, which are, however, challenging in limited application scenarios. Mussel-based biomimetic materials, exhibit numerous unique properties such as intense adhesion, biocompatibility, moisture resistance, and injectability, to name only a few, and have attracted extensive research interest. In particular, featuring state-of-the-art properties, mussel-inspired biomaterials have been widely explored in innumerable musculoskeletal disorder treatments including osteochondral defects, osteosarcoma, osteoarthritis, ligament rupture, and osteoporosis. Nevertheless, a comprehensive and timely discussion of their applications in musculoskeletal disorders is insufficient. In this review, we emphasize on (1) the main categories and characteristics of mussel foot proteins and their fundamental mechanisms for the spectacular adhesion in mussels; (2) the diverse synthetic methods and modification of various polymers; and (3) the emerging applications of mussel-biomimetic materials, the future perspectives, and challenges, especially in the area of musculoskeletal disorder. We envision that this review will provide a unique and insightful perspective to improve the development of a new generation of mussel biomimetic strategies.

Folic Acid-Grafted Chitosan-Alginate Nanocapsules as Effective Targeted Nanocarriers for Delivery of Turmeric Oil for Breast Cancer Therapy

Folate receptors (FRs) highly expressed in breast cancers can be used as a recognized marker for preventing off-target delivery of chemotherapeutics. In this study, folic acid (FA)-grafted chitosan-alginate nanocapsules (CS-Alg-NCs) loaded with turmeric oil (TO) were developed for breast cancer targeting. CS was successfully conjugated with FA via an amide bond with a degree of substitution at 12.86%. The TO-loaded FA-grafted CS-Alg-NCs (TO-FA-CS-Alg-NCs) optimized by Box-Behnken design using response surface methodology had satisfactory characteristics with homogenous particle size (189 nm) and sufficient encapsulation efficiency and loading capacity (35.9% and 1.82%, respectively). In vitro release study of the optimized TO-FA-CS-Alg-NCs showed a sustained TO release following the Korsmeyer-Peppas model with a Fickian diffusion mechanism at pH 5.5 and 7.4. The TO-FA-CS-Alg-NCs showed lower IC₅₀ than ungrafted TO-CS-Alg-NCs and unencapsulated TO against MDA-MB-231 and MCF-7 breast cancer cells, suggesting that FA-CS-Alg-NCs can improve anticancer activity of TO through its active targeting to the high FRs expressing breast cancers.

Expanding the chemical repertoire of protein-based polymers for drug-delivery applications

Expanding the chemical repertoire of natural and artificial protein-based polymers (PBPs) can enable the production of sequence-defined, yet chemically diverse, biopolymers with customized or new properties that cannot be accessed in PBPs composed of only natural amino acids. Various approaches can enable the expansion of the chemical repertoire of PBPs, including chemical and enzymatic treatments or the incorporation of unnatural amino acids. These techniques are employed to install a wide variety of chemical groups-such as bio-orthogonally reactive, cross-linkable, post-translation modifications, and environmentally responsive groups-which, in turn, can facilitate the design of customized PBP-based drug-delivery systems with modified, fine-tuned, or entirely new properties and functions. Here, we detail the existing and emerging technologies for expanding the chemical repertoire of PBPs and review several chemical groups that either demonstrate or are anticipated to show potential in the design of PBP-based drug delivery systems. Finally, we provide our perspective on the remaining challenges and future directions in this field.

A tailored bifunctional carbon catalyst for efficient glycosidic bond fracture and selective hemicellulose fractionation

This study proposed a mild chlorination-sulfonation approach to synthesize magnetic carbon acid bearing with catalytic SO₃H and adsorption Cl bifunctional sites on polydopamine coating. The catalysts exerted good textural structure and surface chemical properties (i.e., porosity, high specific surface area of >70 m²/g, high catalytic activity with 0.86-1.1 mmol/g of SO₃H sites and 0.8%-1.9% of Cl sites, and abundant hydrophilic functional groups), rendering a maximum cellobiose adsorption efficiency of ∼40% within 6 h. Moreover, the catalysts had strong fracture characteristics on different α-/β-glycosidic bonds with 85.4%-93.9% of disaccharide conversion, while selectively fractionating hemicellulose from wheat straw with 64.3% of xylose yield and 93.4% of cellulose retention. Due to the stable interaction between parent polydopamine support with Fe core and functional groups, the catalysts efficiently recovered by simple magnetic separation had good reusability with minimal losses in catalytic activity.

Polysaccharide-based nanocomposites for biomedical applications: a critical review

Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then, applications of NPSA for skin, bone, nerve, and cartilage tissue engineering are highlighted, followed by cell encapsulation and more critically cancer diagnosis and treatment potentials. In particular, three features of investigations are devoted to cancer therapy, i.e., radiotherapy, immunotherapy, and photothermal therapy, are comprehensively reviewed and discussed. Since this field is at an early stage of maturity, some other aspects such as bioimaging and biosensing are reviewed in order to give an idea of potential applications of NPSA for future developments, providing support for clinical applications. It is well-documented that using nanoparticles/nanomaterials above a critical concentration brings about concerns of toxicity; thus, their effect on cellular interactions would become critical. We compared nanoparticles used in the fabrication of NPSA in terms of toxicity mechanism to shed more light on future challenging aspects of NPSA development. Indeed, the neutralization mechanisms underlying the cytotoxicity of nanomaterials, which are expected to be induced by PSA introduction, should be taken into account for future investigations.

A reagentless electrochemical immunosensor for sensitive detection of carcinoembryonic antigen based on the interface with redox probe-modified electron transfer wires and effectively immobilized antibody

Convenient and sensitive detection of tumors marked in serum samples is of great significance for the early diagnosis of cancers. Facile fabrication of reagentless electrochemical immunosensor with efficient sensing interface and high sensitivity is still a challenge. Herein, an electrochemical immunosensor was easily fabricated based on the easy fabrication of immunoassay interface with electron transfer wires, confined redox probes, and conveniently immobilized antibodies, which can achieve sensitive and reagentless determination of the tumor marker, carcinoembryonic antigen (CEA). Carboxyl multi-walled carbon nanotubes (MWCNTs) were firstly modified with an electrochemical redox probe, methylene blue (MB), which has redox potentials distinguished from those of redox molecules commonly existing in biological samples (for example, ascorbic acid and uric acid). After the as-prepared MB-modified MWCNT (MWCNT-MB) was coated on the supporting glassy carbon electrode (GCE), the MWCNT-MB/GCE exhibited improved active area and electron transfer property. Polydopamine (PDA) was then in situ synthesized through simple self-polymerization of dopamine, which acts as the bio-linker to covalently immobilize the anti-CEA antibody (Ab). The developed immunosensor could be applied for electrochemical detection of CEA based on the decrease in the redox signal of MB after specific binding of CEA and immobilized Ab. The fabricated immunosensor can achieve sensitive determination of CEA ranging from 10 pg/ml to 100 ng/ml with a limit of detection (LOD) of 0.6 pg/ml. Determination of CEA in human serum samples was also realized with high accuracy.

Development of a Hemostatic Urinary Catheter for Transurethral Prostatic Surgical Applications

OBJECTIVE

To investigate a novel transurethral hemostatic catheter device with an integrated chitosan endoluminal hemostatic dressing (CEHD). Development and implementation of this technology may help address bleeding following surgery such as transurethral resection of prostate (TURP). Bleeding remains the most common complication following TURP, leading to increased morbidity and hospitalization.

METHODS

Investigation of hemostasis, delivery, safety and efficacy of the CEHD device is conducted using Female Yorkshire swine (N = 23). Hemostatic efficacy of the CEHD (N = 12) is investigated against a control of gauze (N = 12) in a splenic injury model (3 swine). The delivery, safety, and efficacy of the CEHD device (N = 10) are investigated against Foley-catheter control (N = 10) for 7 days using a swine bladder-neck-injury model.

RESULTS

In the splenic injury study, 9/12 CEHD dressings successfully achieved hemostasis within 150 seconds (mean 83 seconds) vs success of 6/12 (mean 150 seconds) for gauze (P = .04). In the 7-day study, the CEHD was successfully deployed in 10/10 animals and all dressings were tolerated without histologic or clinical adverse effect. Hemostasis of the CEHD device was found to be noninferior to control catheters. Noninferiority is attributed to low bleeding rates in the swine bladder neck injury model.

CONCLUSION

This investigation successfully demonstrated the feasibility of transurethral deployment of the CEHD in vivo. Routine use of safe and slowly dissolvable CEHDs could reduce the rate of complications and hospitalizations associated with bleeding and blood loss in TURP procedures. Further investigation is warranted.

Hemocompatibility of Galactomannan and Galactoglucomannan Sulfates in In Vitro Experiments

We identified compounds that do not independently provoke aggregation of human platelets and do not affect hemolysis of human erythrocytes in vitro: lacking anticoagulant activity sulfated galactoglucomannan (polydispersity 1.43; degree of sulfation 0.66) in concentrations ≤0.2 mg/ml; exhibiting anticoagulant activity (in concentrations up to 0.002 mg/ml) sulfated galactoglucomannan (polydispersity 1.5; degree of sulfation 1.81) and galactomannan obtained by sulfation with the sulfamic acid-urea complex (polydispersity 2.75; degree of sulfation 1.25) and galactomannans obtained by sulfation with chlorosulfonic acid in 1,4-dioxane (polydispersity 1.61/22.27; degree of sulfation 1.00/0.74).

Multilayered mucoadhesive hydrogel films based on Ocimum basilicum seed mucilage/thiolated alginate/dopamine-modified hyaluronic acid and PDA coating for sublingual administration of nystatin

The present study establishes an experimental design for the preparation of new bi and tri-layer mucoadhesive sublingual films based on basil (Ocimum basilicum L.) seed mucilage (OBM) as novel plant-polysaccharide for oromucosal administration of nystatin (Nys). The films formulation consists of a drug reservoir-mucoadhesive layer cross-linked via CaCl₂, with protective mucoadhesive layers based on thiolated alginate (TA) and polydopamine (PDA). OBM served as a new mucoadhesive polysaccharide in second layers, where the dopamine-modified-hyaluronic acid (DHA) improved the mucoadhesive strength and swelling rate properties. The drug-loaded formulations of trilayer film with PDA coating, and bilayer film with DHA/OBM (1:1) in the second layer, showed the desired mucoadhesion properties (about 69 and 75.3% respectively). The obtained results revealed that the bilayer film containing DHA had a superior swelling degree in the range of 15-19 (g/g). While the PDA coating sample showed the highest resistance to water uptake and erosion. The bilayer film (DHA/OBM with 1:1 ratio) provided a maximum drug release of 86% after 4 h. The selected formulations indicated good mechanical properties with no cytotoxicity.

Modification of Silica Xerogels with Polydopamine for Lipase B from Candida antarctica Immobilization

Silica xerogels have been proposed as a potential support to immobilize enzymes. Improving xerogels’ interactions with such enzymes and their mechanical strengths is critical to their practical applications. Herein, based on the mussel-inspired chemistry, we demonstrated a simple and highly effective strategy for stabilizing enzymes embedded inside silica xerogels by a polydopamine (PDA) coating through in-situ polymerization. The modified silica xerogels were characterized by scanning and transmission electron microscopy, Fourier tranform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and pore structure analyses. When the PDA-modified silica xerogels were used to immobilize enzymes of Candida antarctica lipase B (CALB), they exhibited a high loading ability of 45.6 mg/gsupport, which was higher than that of immobilized CALB in silica xerogels (28.5 mg/gsupport). The immobilized CALB of the PDA-modified silica xerogels retained 71.4% of their initial activities after 90 days of storage, whereas the free CALB retained only 30.2%. Moreover, compared with the immobilization of enzymes in silica xerogels, the mechanical properties, thermal stability and reusability of enzymes immobilized in PDA-modified silica xerogels were also improved significantly. These advantages indicate that the new hybrid material can be used as a low-cost and effective immobilized-enzyme support.

A conductive polyacrylamide hydrogel enabled by dispersion-enhanced MXene@chitosan assembly for highly stretchable and sensitive wearable skin

MXene is recognized as an ideal material for sensitive wearable strain sensors because of its unique advantages of conductivity, hydrophilicity and mechanical properties. However, conventional hydrogel sensors utilizing MXene as a conductive material inevitably encounter the excessive accumulation of MXene nanosheets during the process of synthesis, which limits the electron transmission, reduces the conductivity, and concurrently weakens the mechanical capability and sensitivity of sensors. Herein, we construct a dispersion-enhanced MXene hydrogel (DEMH) through a chitosan-induced self-assembly strategy for the first time. Charge transfer is carried out through the flow of a material or a collection of material microstructures, and thus the highly interconnected 3D MXene@Chitosan network provides fast transport channels for electrons, and the DEMH exhibits excellent conductivity and sensibility simultaneously. Besides, the electrostatic self-assembly between MXene and chitosan, and the supramolecular interactions between MXene, chitosan and polyacrylamide chain segment result in excellent mechanical strength (of up to 1900%) and flexibility of DEMH. Furthermore, the introduction of chitosan which possesses a high density of positively charged groups and MXene with semiconducting properties also endows sensor versatility, such as self-adhesion properties and antibacterial activity. This work develops a simple and cut-price strategy for combining MXene unaggregated into a hydrogel as a sensor with high conductivity, sensibility and flexibility. A simple and inexpensive strategy for avoiding self-stacking of two-dimensional conductive materials is proposed, which paves the way for a broad range of applications in electronic skin, human motion detection and intelligent devices.

Design of an amperometric glucose oxidase biosensor with added protective and adhesion layers

Enzymes have demonstrated great potential in the development of advanced electroanalysis devices due to their unique recognition and catalytic properties. However, unsatisfactory stability and limited electron communication of traditional enzyme sensors seriously hinder their large-scale application. In this work, a simple and effective method is proposed to improve the stability of enzyme sensors by using sodium hyaluronate (SH) as a protective film, MXene-Ti₃C₂/Glucose oxidase (GOD) as the reaction layer, and chitosan (CS) /reduced graphene oxide (rGO) as the adhesion layer. Results demonstrate that the repeatability of the designed sensor increased by 73.3% after improving the adhesion between the reaction layer and the current collector and that its response ability was greatly enhanced. Moreover, the long-term stability of the electrode surface with SH protective film proved to be superior than that without protective film, which suggests that this design can effectively improve the overall performance of the enzyme biosensor. This work proposed a multi-tier synergistic approach for improving the reliability of enzyme sensors. Graphical abstract Our proposed protective and adhesion layer can greatly improve the stability of enzyme sensor and realize the rapid detection of glucose in serum sample.