Effect of chitosan and carboxymethyl chitosan on fibrinogen structure and blood coagulation

Engineering Wet-Resistant and Osteogenic Nanocomposite Adhesive to Control Bleeding and Infection after Median Sternotomy

Median sternotomy surgery stands as one of the prevailing strategies in cardiac surgery. In this study, the cutting-edge bone adhesive is designed, inspired by the impressive adhesive properties found in mussels and sandcastle worms. This work has created an osteogenic nanocomposite coacervate adhesive by integrating a cellulose-polyphosphodopamide interpenetrating network, quaternized chitosan, and zinc, gallium-doped hydroxyapatite nanoparticles. This adhesive is characterized by robust catechol-metal coordination which effectively adheres to both hard and soft tissues with a maximum adhesive strength of 900 ± 38 kPa on the sheep sternum bone, surpassing that of commercial bone adhesives. The release of zinc and gallium cations from nanocomposite adhesives and quaternized chitosan matrix imparts remarkable antibacterial properties and promotes rapid blood coagulation, in vitro and ex vivo. It is also proved that this nanocomposite adhesive exhibits significant in vitro bioactivity, stable degradability, biocompatibility, and osteogenic ability. Furthermore, the capacity of nanocomposite coacervate to adhere to bone tissue and support osteogenesis contributes to the successful healing of a sternum bone defect in a rabbit model in vivo. In summary, these nanocomposite coacervate adhesives with promising characteristics are expected to provide solutions to clinical issues faced during median sternotomy surgery.

Antibiofilm and antithrombotic hydrogel coating based on superhydrophilic zwitterionic carboxymethyl chitosan for blood-contacting devices

Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections, thrombosis, and intimal lesions caused by surface friction. However, achieving effective prevention of both bloodstream-associated infections and thrombosis poses a challenge due to the conflicting nature of antibacterial and antithrombotic activities, specifically regarding electrostatic interactions. This study introduced a novel biocompatible hydrogel of sodium alginate and zwitterionic carboxymethyl chitosan (ZW@CMC) with antibacterial and antithrombotic activities for use in catheters. The ZW@CMC hydrogel demonstrates a superhydrophilic surface and good hygroscopic properties, which facilitate the formation of a stable hydration layer with low friction. The zwitterionic-functionalized CMC incorporates an additional negative sulfone group and increased negative charge density in the carboxyl group. This augmentation enhances electrostatic repulsion and facilitates the formation of hydration layer. This leads to exceptional prevention of blood clotting factor adhesion and inhibition of biofilm formation. Subsequently, the ZW@CMC hydrogel exhibited biocompatibility with tests of in vitro cytotoxicity, hemolysis, and catheter friction. Furthermore, in vivo tests of antithrombotic and systemic inflammation models with catheterization indicated that ZW@CMC has significant advantages for practical applications in cardiovascular-related and sepsis treatment. This study opens a new avenue for the development of chitosan-based multifunctional hydrogel for applications in blood-contacting devices.

Influence of Surface-Modification via PEGylation or Chitosanization of Lipidic Nanocarriers on In Vivo Pharmacokinetic/Pharmacodynamic Profiles of Apixaban

Nanostructured lipid carriers (NLCs) have been proven to significantly improve the bioavailability and efficacy of many drugs; however, they still have many limitations. These limitations could hinder their potential for enhancing the bioavailability of poorly water-soluble drugs and, therefore, require further amendments. From this perspective, we have investigated how the chitosanization and PEGylation of NLCs affected their ability to function as a delivery system for apixaban (APX). These surface modifications could enhance the ability of NLCs to improve the bioavailability and pharmacodynamic activity of the loaded drug. In vitro and in vivo studies were carried out to examine APX-loaded NLCs, chitosan-modified NLCs, and PEGylated NLCs. The three nanoarchitectures displayed a Higuchi-diffusion release pattern in vitro, in addition to having their vesicular outline proven via electron microscopy. PEGylated and chitosanized NLCs retained good stability over 3 months, versus the nonPEGylated and nonchitosanized NLCs. Interestingly, APX-loaded chitosan-modified NLCs displayed better stability than the APX-loaded PEGylated NLCs, in terms of mean vesicle size after 90 days. On the other hand, the absorption profile of APX (AUC_0-inf) in rats pretreated with APX-loaded PEGylated NLCs (108.59 µg·mL^-1·h^-1) was significantly higher than the AUC_0-inf of APX in rats pretreated with APX-loaded chitosan-modified NLCs (93.397 µg·mL^-1·h^-1), and both were also significantly higher than AUC_0-inf of APX-Loaded NLCs (55.435 µg·mL^-1·h^-1). Chitosan-coated NLCs enhanced APX anticoagulant activity with increased prothrombin time and activated partial thromboplastin time by 1.6- and 1.55-folds, respectively, compared to unmodified NLCs, and by 1.23- and 1.37-folds, respectively, compared to PEGylated NLCs. The PEGylation and chitosanization of NLCs enhanced the bioavailability and anticoagulant activity of APX over the nonmodified NLCs; this highlighted the importance of both approaches.

Prospective, randomized, controlled, noninferiority clinical trial to evaluate the safety and efficacy of absorbable macroporous polysaccharide composites as adjunct to hemostasis during open surgery

BACKGROUND

To address intraoperative bleeding in cardiac surgery, reducing blood transfusion requirements, is mandatory to achieve effective hemostasis. Hemostatic agents may limit localized persistent bleeding. The introduction of carboxymethyl-chitosan component into the hemostatic agent and the application of the radiation crosslinking technique maintain its capacity for achieving intraoperative hemostasis, thus increasing the clinical utility.

METHODS

A prospective, noninferiority and randomized controlled clinical trial to compare the safety and efficacy of absorbable macroporous polysaccharide composites (AMPC, treatment group) with compound microporous polysaccharide hemostatic powder (CMPHP, control group) (2:1 ratio) as adjuncts to hemostasis in open surgery. The main indication was used for hemostasis in various traumatic hemorrhage areas, including cardiothoracic, vascular, and general surgery. The primary endpoint was success rate of hemostasis within 300 s (at a 10% noninferiority margin). The secondary endpoint was hemostasis time. Both endpoints were assessed in the modified intention-to-treat (MITT) population. Safety parameters were assessed. This study is fully compliant with the CONSORT statement.

RESULTS

Randomized patients in AMPC and CMPHP groups were 168 and 84, respectively. In MITT population, the success rates of hemostasis within 300 s were 98.8% (163 of 165) in AMPC and 94.0% (78 of 83) in CMPHP (treatment difference 4.8% [95% CI -0.57% to 10.20%]). AMPC was thus noninferior to CMPHP. Hemostasis time (median [interquartile range]) with AMPC (87 [52.5, 180] s) was better than CMPHP (110 [54.5, 181] s). Changes in laboratory parameters over time and shifts to abnormal values were typical of surgeries and similar between two groups. No noticeable adverse effects associated with AMPC or CMPHP were observed.

CONCLUSIONS

AMPC is well tolerated as topical hemostatic agent, noninferior to commercial CMPHP, and exhibits excellent safety. This study provides a novel hemostatic agent which appears to offer significant clinical advantage in various hemorrhage areas.

The Bioflavonoids Rutin and Rutin Succinate Neutralize the Toxins of B. jararaca Venom and Inhibit its Lethality

The venom of the Brazilian pit viper Bothrops jararaca (BjV) is a complex mixture of molecules, and snake venom metalloproteinases (SVMP) and serine proteinases (SVSP) are the most abundant protein families found therein. Toxins present in BjV trigger most of the deleterious disturbances in hemostasis observed in snakebites, i.e., thrombocytopenia, hypofibrinogenemia and bleedings. The treatment of patients bitten by snakes still poses challenges and the bioflavonoid rutin has already been shown to improve hemostasis in an experimental model of snakebite envenomation. However, rutin is poorly soluble in water; in this study, it was succinylated to generate its water-soluble form, rutin succinate (RS), which was analyzed comparatively regarding the chemical structure and characteristic features of rutin. Biological activities of rutin and RS were compared on hemostatic parameters, and against toxic activities of crude BjV in vitro. In vivo, C57BL/6 mice were injected i.p. with either BjV alone or pre-incubated with rutin, RS or 1,10-phenanthroline (o-phe, an SVMP inhibitor), and the survival rates and hemostatic parameters were analyzed 48 h after envenomation. RS showed the characteristic activities described for rutin - i.e., antioxidant and inhibitor of protein disulfide isomerase - but also prolonged the clotting time of fibrinogen and plasma in vitro. Differently from rutin, RS inhibited typical proteolytic activities of SVMP, as well as the coagulant activity of BjV. Importantly, both rutin and RS completely abrogated the lethal activity of BjV, in the same degree as o-phe. BjV induced hemorrhages, falls in RBC counts, thrombocytopenia and hypofibrinogenemia in mice. Rutin and RS also improved the recovery of platelet counts and fibrinogen levels, and the development of hemorrhages was totally blocked in mice injected with BjV incubated with RS. In conclusion, RS has anticoagulant properties and is a novel SVMP inhibitor. Rutin and RS showed different mechanisms of action on hemostasis. Only RS inhibited directly BjV biological activities, even though both flavonoids neutralized B. jararaca toxicity in vivo. Our results showed clearly that rutin and RS show a great potential to be used as therapeutic compounds for snakebite envenomation.

Fluorescent chitosan-BODIPY macromolecular chemosensors for detection and removal of Hg2+ and Fe3+ ions

The detection of heavy metals, such as Hg2+ and Fe3+, is of great significance. In this work, fluorescent small-molecule BODIPY (BY-3) bearing CC group was synthesized firstly. And then, the chitosan-based polymer sensor CY-1 was synthesized through the spontaneous NH2/C≡C click reaction. The synthesized CY-1 can effectively bind and recognize Hg2+/Hg+ by the -C=N groups formed in the click reaction. Moreover, the macromolecular sensors CS-1 and CS-2 were synthesized by incorporating another recognition sites to CY-1. These synthesized macromolecular sensors can not only recognize Hg2+/Hg+, but also effectively recognize Fe3+/Fe2+. All of them exhibited significant quenching effect, visible to the naked eye under UV irradiation. The detection limit of CY-1 for Hg2+ was 1.51 × 10-6 mol/L, and the detection limit of CS-2 for Fe3+ was 2.30 × 10-6 mol/L. The BODIPY-chitosan sensors synthesized in this work have the functions of removing heavy metal ions besides the identifying ability. The maximum adsorption capacity of 1 g chitosan to Hg2+ was 108 mg as the best one. This article provides a new method to prepare macromolecular sensors for the detection and removal of heavy metal ions. As a useful natural polymer, chitosan's application scope was enlarged.

Exploring the role of chitosan in affecting the adhesive, rheological and antimicrobial properties of carboxymethyl cellulose composite hydrogels

Natural polysaccharide-based hydrogels are promising in food and pharmaceutical applications. In this study, the potential of composite hydrogels prepared by carboxymethyl cellulose (CMC) and chitosan as glue for cigar wrapping applications was firstly studied. The impacts of degree of carboxymethyl substitution (DS) and the ratio of CMC:chitosan on the adhesive performance and rheological behaviors of composite hydrogels have been investigated. And the results indicated that relatively low DS of CMC and relatively low ratio of chitosan might be favorable for the adhesive properties of composite hydrogels. But a higher ratio of chitosan may significantly improve the rheological properties of composite hydrogels and alter their thermal-sensitivity. The impacts of chitosan on the wet ability with tobacco leaf, the morphology and the XRD patterns of composite hydrogels were also observed. The CMC-chitosan composite hydrogel could significantly decrease the total molds on tobacco leaf brought by CMC, and therefore may show great potential to improve the quality of cigar during long-term storage. All the information in this study is new, which could be useful for exploring the application of CMC-chitosan composite hydrogel in food, pharmaceutical, even other fields.

Evaluation of the effects of nanoparticles on the therapeutic function of platelet: a review

OBJECTIVES

Nanotechnology and nanoparticles are used in different applications in disease monitoring and therapy in contact with blood. Nanoparticles showed different effects on blood components and reduced or improved the function of therapeutic platelet during the storage time. This review study was performed to evaluate the impacts of various sizes and charges of nanoparticles on platelet function and storage time. The present review contains the literature between 2010 and 2020. The data have been used from different sites such as PubMed, Wiley, ScienceDirect and online electronic journals.

KEY FINDINGS

From the literature survey, it has been demonstrated that among various properties, size and charge of nanoparticles were critical on the function of therapeutic platelet during the storage and inhibition of their aggregation. Overall, this study described that nanoparticles with smaller size and negative charge were more effective in increasing the survival time, inhibition of aggregation and improving the function of therapeutic platelet.

SUMMARY

Based on the current review, it can be confirmed that nanoparticles such as dendrimer, Au, Ag and iron oxide nanoparticles with smaller size and negative charge have significant advantages for improving the efficacy of platelets during the storage chain and inhibition of their aggregation.

Preparation of biocompatible wound dressings with dual release of antibiotic and platelet-rich plasma for enhancing infected wound healing

The ever-growing threats of bacterial infection and chronic wound healing have provoked an urgent need for novel antibacterial wound dressings. In this study, we developed a wound dressing for the treatment of infected wounds, which can reduce the inflammatory period (through the use of gentamycin sulfate (GS)) and enhance the granulation stage (through the addition of platelet-rich plasma (PRP)). Herein, the sustained antimicrobial CMC/GMs@GS/PRP wound dressings were developed by using gelatin microspheres (GMs) loading GS and PRP, covalent bonding to carboxymethyl chitosan (CMC). The prepared dressings exhibited high water uptake capability, appropriate porosity, excellent mechanical properties, sustain release of PRP and GS. Meanwhile, the wound dressing showed good biocompatibility and excellent antibacterial ability against Gram-negative and Gram-positive bacteria. Moreover, in vivo experiments further demonstrated that the prepared dressings could accelerate the healing process of E. coli and S. aureus-infected full-thickness wounds in vivo, reepithelialization, collagen deposition and angiogenesis. In addition, the treatment of CMC/GMs@GS/PRP wound dressing could reduce bacterial count, inhibit pro-inflammatory factors (TNF-α, IL-1β and IL-6), and enhance anti-inflammatory factors (TGF-β1). The findings of this study suggested that biocompatible wound dressings with dual release of GS and PRP have great potential in the treatment of chronic and infected wounds.

Nanoformulation of fibrinogen by thermal stabilization of its electrostatic complexes with hyaluronic acid

The formulation of well-defined and stable fibrinogen-based nanoparticles (NPs) without the use of any chemical reaction or any toxic organic solvent is reported. Electrostatic interaction between hyaluronic acid (HA) and fibrinogen (Fbg) leads to well-defined complexes at acidic pH which however readily dissolve at neutral pH. On the other hand, when thermal treatment is applied on the pre-formed complexes NPs keep their integrity. Circular dichroism indicates that the protein's native secondary conformation in the final NPs is not affected by the formulation. The tendency of the complexes to aggregate at elevated ionic strengths is greatly suppressed after the application of the temperature treatment protocol. This characteristic is even more pronounced at neutral pH and it is connected to the enhanced surface charge of the NPs. The encapsulation of the hydrophobic compound curcumin causes only weak secondary aggregation. This work shows that the ability of Fbg to self-assemble upon thermal treatment can be effectively used to stabilize Fbg nanoformulations inside complexes with polysaccharides.

Current Development on Chitosan-based Antimicrobial Drug Formulations for the Wound Healing

BACKGROUND

Derived from polyose, chitosan is an outstanding natural linear polysaccharide comprised of random arrangement of β-(1-4)-linked D-Glucosamine and N-acetyl-DGlucosamine units.

OBJECTIVE

Researchers have been using chitosan as a network forming or gelling agent with economically available, present polyose, low immunogenicity, biocompatibility, non-toxicity, biodegradability, protects against secretion from irritation and don't suffer the danger of transmission animal infective agent.

METHODS

Furthermore, recent studies gear up the chitosan used in the development of various biopharmaceutical formulations, including nanoparticles, hydrogels, implants, films, fibers, etc. Results: These formulations produce potential activities as antimicrobials, cancer treatment, medical aid, and wound healing, controlled unleash device or drug trigger retarding device and 3DBiomedical sponge, etc. Conclusion: The present article discusses the development of various drug formulations utilizing chitosan as biopolymers for the repairing of broken tissues and healing in case of wound infection.

An innovative blood plasma separation method for a paper-based analytical device using chitosan functionalization

This study describes a microfluidic paper-based analytical device (μPAD) for separating plasma from whole blood and measuring glucose concentration.

Self-assembling RATEA16 peptide nanofiber designed for rapid hemostasis

In this study, we synthesized a novel polypeptide material, RATEA16, by the solid phase method, and investigated the secondary structure, self-assembly performance, gelation ability, biocompatibility and hemostatic efficiencyin vitroandin vivo.

Biological Effects of Chitosan-Based Dressing on Hemostasis Mechanism

There have been numerous recent advances in wound care management. Nevertheless, the assessment of hemostatic dressing is essential to enable surgeons and other physicians and healthcare professionals to make the correct decisions regarding the disposition of severe hemorrhage. Here, we investigated the relative efficacies of chitosan-based and conventional gauze dressings in a rat model of femoral artery hemorrhage and in patients with surgical wounds. Dressing effectiveness was evaluated based on hemostatic profiles, biocompatibility, antimicrobial activity, and blood factor responses in coagulation. Relative to standard gauze dressing, the chitosan fiber (CF) dressing treatment significantly shortened the time to hemostasis in injured rats. Moreover, the CF dressing significantly prolonged partial thromboplastin time, enhanced blood absorption, and reduced antithrombin production without altering the prothrombin ratio. Unlike regular gauze bandages, the CF dressing demonstrated remarkable antibacterial activity. The results of this study indicate the effectiveness of chitosan as a hemostatic dressing and elucidate its underlying mechanism. It is possible that chitosan surgical dressings could serve as first-line intervention in hospital emergency care for uncontrolled hemorrhage.

Tranexamic acid-loaded starch hemostatic microspheres

Efficacious hemostatics have significant potential for use in rapid exsanguinating hemorrhage control by emergency medical technicians or military medics nowadays. Current hemostatics focus primarily on speeding up the formation of blood clots, but inhibiting fibrinolysis is also critical for promoting coagulation and improving survival rates. Here we report a drug-loaded cross-linked microporous starch (TACMS) fabricated by loading tranexamic acid (TA) with antifibrinolytic properties into cross-linked microporous starch (CMS). The results showed that the cross-linking modification improved the mechanical properties and the particle density. The introduction of TA had no influence on water absorption of CMS. TACMS retained good physical hemostatic capacity and excellent biocompatibility. The prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) of TACMS with 20 mg g⁻¹ of TA were shortened greatly, indicating the chemical hemostasis of TACMS. TACMS demonstrated a 70% reduction in clotting time in vitro compared to CMS, which effectively inhibited the dissolution of fibrin and increased the strength of blood clots. Importantly, TACMS presented excellent hemostatic performance in rabbit ear artery injury and rabbit liver injury and even better hemostatic ability than Arista®. In conclusion, cross-linking, enzyme hydrolysis and modification of starch greatly improved absorption speed, blood uptake capacity and mechanical strength, and the introduction of TA simultaneously amplified the physical hemostasis and inhibited the dissolution of fibrin. The potent hemostatic ability of TACMS resulted from the synergistic role of physical hemostasis and drug hemostasis. The results of the present study put forward TACMS as a safe and effective hemostatic system and present a platform for further optimization studies of materials with enhanced hemostatic capabilities for specific injury types.

Efficacious hemostatics have significant potential for use in rapid exsanguinating hemorrhage control by emergency medical technicians or military medics nowadays.

Effects of Chitosan Oligosaccharides on Human Blood Components

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

Biocompatibility studies of intravenously administered ionic-crosslinked chitosan-BSA nanoparticles as vehicles for antitumour drugs

In this study, a new alternative of ionic crosslinked nanoparticles (NPs) based on chitosan (C) and bovine serum albumin (A; BSA) was evaluated as drug delivery system for antitumour compounds (doxorubicin hydrochloride as a model). The different responses to the pH of the medium were determined by the electrostatic interactions induced by each polymeric combination (C50/A50; C80/A20; C20/A80). NPs revealed a nanoscale size (167-392 nm) and a positive net charge (12-26 mV), modulated by doxorubicin (DOX) loading. Drug loading capacity was higher than 5.2 ± 1.8 μgDOX/mgNP (Encapsulation efficiency = 34%), and an initial burst release was followed by a sustained delivery. Cellular uptake assays confirmed the entry of NPs in three human tumor cells (MCF7, T47D and Hela), triggering antioxidant responses (superoxide dismutase, catalase, glutathione reductase and total glutathione content) in those cells. This was also consistent with the decreased in IC50 values observed after the incubation of these cells with C20/A80-DOX and C50/A50-DOX NPs (1.90-3.48 μg/mL) compared with free DOX (2.36-6.025 μg/mL). In vivo results suggested that the selected proportions of chitosan-BSA created nonhemolytic and biocompatible stable NPs at the selected dose of 20 mg/kg. Despite the different formulations, this study demonstrated that these NPs could serve as safe drug carriers in further in vivo investigations.

Modification of a commercial thromboelastography instrument to measure coagulation dynamics with three-dimensional biomaterials

Three-dimensional synthetic constructs with complex geometries have immense potential for use in a multitude of blood-contacting applications. Understanding coagulation phenomena is arguably the most critical aspect for applications involving synthetic biomaterials; however, real-time evaluation of the clot formation while interfacing with these materials is difficult to achieve in a reproducible and robust manner. Here, work representing first steps toward addressing this deficit is presented, wherein modified consumables for a clinical instrument (a Thromboelastograph(®)) have been fabricated. Thromboelastography (TEG) measures viscoelastic properties throughout clot formation and therefore provides clinically relevant coagulation measurements in real time (i.e., kinetics and strength of clot formation). Through our modification, TEG consumables can readily accommodate three-dimensional materials (e.g., those for regenerative tissue applications). The authors performed proof-of-concept experiments using polymer scaffolds with a range of surface properties and demonstrated that variations in surface properties resulted in differences in blood plasma coagulation dynamics. For example, the maximum rate of thrombus generation ranged from 22.2 ± 2.2 (dyn/cm(2))/s for fluorocarbon coated scaffolds to 8.7 ± 1.0 (dyn/cm(2))/s for nitrogen-containing scaffolds. Through this work, the ability to make real-time coagulation activity measurements during constant coagulation factor interface with biomedically relevant materials is demonstrated.

Blood compatibility evaluations of poly(ethylene glycol)-poly(lactic acid) copolymers

Poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) copolymers have been widely used for various biomedical applications. However, their hemocompatibility has not been clarified, which would lag their developments and clinical applications. In this work, we studied the effect of PEG-PLA copolymers on key human blood components in terms of their structure and bio-functions, including morphology and lysis of red blood cells, fibrinogen structure and conformation, and plasma and blood coagulation. To elucidate a structure-activity relationship, we used diblock PEG-PLA copolymers with different molecular weight, PEG(5 kDa)-PLA(25 kDa) and PEG(2 kDa)-PLA(2 kDa), abbreviated as PEG5k-PLA25k and PEG2k-PLA2k, respectively. The results show that the PEG-PLA copolymers at the concentration range studied in this work neither caused morphological alteration and lysis of red blood cells nor affected the oxygen delivery function and fibrinogen conformation. PEG5k-PLA25k from 10 to 100 mg/mL and PEG2k-PLA2k from 1.5 to 5 mg/mL disturbed the local microenvironments of fibrinogen molecules. PEG5k-PLA25k at up to 0.1 mg/mL did not interfere in the coagulation process of plasma or whole blood, while PEG2k-PLA2k from 0.1 mg/mL significantly interfered in the intrinsic plasma coagulation pathway and impaired whole blood coagulation. The results provide important information for the molecular design and clinical applications of PEG-PLA copolymers.

Synthesis, characterisation and preliminary investigation of the haemocompatibility of polyethyleneimine-grafted carboxymethyl chitosan for gene delivery

The development of safe and efficient gene carriers is the key to the clinical success of gene therapy. In the present study, carboxymethyl chitosan (CMCS) was prepared by chitosan (CS) alkalisation and carboxymethylation reactions. Then polyethyleneimine (PEI) was grafted to the backbone of CMCS by an amidation reaction. The CMCS-PEI copolymer showed strong complexation capability with DNA to form nanoparticles, and achieved lower cytotoxicity and higher transfection efficiency compared with PEI (25 kDa) towards 293T and 3T3 cells. Moreover, the haemocompatibility of the CMCS-PEI copolymer was investigated through the aggregation, morphology and lysis of human red blood cells (RBCs), along with the impact on the clotting function with activated partial thromboplastin time (APTT), prothrombin time (PT) and thromboelastographic (TEG) assays. The results demonstrated that the CMCS-PEI copolymer with a concentration lower than 0.05 mg/mL had little impact on the aggregation, morphology or lysis of RBCs, or on blood coagulation. Therefore, the copolymer may be a strong alternative candidate as an effective and safe non-viral vector.

Hemocompatibility evaluation in vitro of methoxy polyethyleneglycol-polycaprolactone copolymer solutions

Amphiphilic block copolymer methoxy polyethyleneglycol-polycaprolactone (mPEG-PCL) has attracted interest in the biomedical field, due to its water solubility and biodegradability. Nevertheless, the blood safety of mPEG-PCL copolymers has not been investigated in detail. Because mPEG-PCL copolymers introduced in vivo would inevitably interact with blood tissue, an investigation of possible interactions of mPEG-PCL with key blood components is crucial. We studied the effects of two mPEG-PCL copolymer solutions on blood coagulation, the morphology and lysis of human red blood cells (RBCs), the structure of plasma fibrinogen, complement activation, and platelet aggregation. We found that higher concentrations of the mPEG-PCL copolymers impaired blood clotting, and the copolymers had little impact on the morphology or lysis of RBCs. From the spectroscopy results, the copolymers affected the local microstructure of fibrinogen. The copolymers significantly activated the complement system in a concentration-dependent way. At higher concentrations, the copolymers impaired platelet aggregation, which may have been mediated by an inhibition of the arachidonic acid pathway. These findings provide important information that may be useful for the molecular design and biomedical applications of mPEG-PCL copolymers. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 802-812, 2016.

Binding interaction between rice glutelin and amylose: Hydrophobic interaction and conformational changes

The interaction of rice glutelin (RG) with amylose was characterized by spectroscopic and molecular docking studies. The intrinsic fluorescence of RG increased upon the addition of amylose. The binding sites, binding constant and thermodynamic features indicated that binding process was spontaneous and the main driving force of the interaction was hydrophobic interaction. The surface hydrophobicity of RG decreased with increasing amount of amylose. Furthermore, synchronous fluorescence and circular dichroism (CD) spectra provided data concerning conformational and micro-environmental changes of RG. With the concentration of amylose increasing, the polarity around the tyrosine residues increased while the hydrophobicity decreased. Alteration of protein conformation was observed with increasing of α-helix and reducing of β-sheet. Finally, a visual representation of two binding sites located in the amorphous area of RG was presented by molecular modeling studies.

Effect of cyclodextrins on the structure and functions of blood components in vitro

Cyclodextrins have been extensively used in various biomedical and pharmaceutical applications. In these applications, cyclodextrins administered in vivo would inevitably enter blood stream. However, there is not enough information on the hemocompatibility of cyclodextrins until now. In this study, we investigated the influences of cyclodextrins (α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin) on human blood components and functions in vitro, that is, morphology and lysis of red blood cells, structure and conformation of fibrinogen, complement activation, and blood coagulation. It was found that 10 mg/mL of α- or β-cyclodextrins caused abnormal red blood cell morphology and serious hemolysis, while γ-cyclodextrin at 10 mg/mL did not impair red blood cell membrane morphology and integrity. The three cyclodextrins at up to 10 mg/mL affected the local microstructure but did not change the conformation of fibrinogen. The three cyclodextrins from 0.01 to 1 mg/mL all significantly activated the complement system in a concentration-dependent way. The three cyclodextrins at up to 5 mg/mL in blood plasma did not cause significantly different coagulation times compared with the negative control. In addition, the three cyclodextrins at up to 5 mg/mL in whole blood did not cause abnormal coagulation parameters. These results provide significant information on blood safety of the three cyclodextrins for their biomedical and pharmaceutical applications.

Hemocompatibility improvement of perfusion-decellularized clinical-scale liver scaffold through heparin immobilization

Whole-liver perfusion-decellularization is an attractive scaffold–preparation technique for producing clinical transplantable liver tissue. However, the scaffold’s poor hemocompatibility poses a major obstacle. This study was intended to improve the hemocompatibility of perfusion-decellularized porcine liver scaffold via immobilization of heparin. Heparin was immobilized on decellularized liver scaffolds (DLSs) by electrostatic binding using a layer-by-layer self-assembly technique (/h-LBL scaffold), covalent binding via multi-point attachment (/h-MPA scaffold), or end-point attachment (/h-EPA scaffold). The effect of heparinization on anticoagulant ability and cytocompatibility were investigated. The result of heparin content and release tests revealed EPA technique performed higher efficiency of heparin immobilization than other two methods. Then, systematic in vitro investigation of prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT), platelet adhesion and human platelet factor 4 (PF4, indicates platelet activation) confirmed the heparinized scaffolds, especially the /h-EPA counterparts, exhibited ultralow blood component activations and excellent hemocompatibility. Furthermore, heparin treatments prevented thrombosis successfully in DLSs with blood perfusion after implanted in vivo. Meanwhile, after heparin processes, both primary hepatocyte and endothelial cell viability were also well-maintained, which indicated that heparin treatments with improved biocompatibility might extend to various hemoperfusable whole-organ scaffolds’ preparation.

Effect of different chitosan derivatives on in vitro scratch wound assay: a comparative study

Different strategies have been developed to make the wound-healing process faster and less painful. Recently, numerous studies demonstrated the ability of chitosan to accelerate wound healing. Aim of the present study has been to evaluate the effect of different chitosan derivatives to improve wound healing process. Quaternary ammonium-chitosan conjugates with low or high molecular weight (MW) and their thiolated derivatives effect were studied on human skin fibroblasts in terms of viability and migration (scratch wound assay). Results were compared both with basal medium (untreated cells) and with a positive control (chitosan chlorhydrate). After 24h both high and low MW chitosan derivatives were non-toxic up to 10 μg/ml. The concentration of 10 μg/ml was used for wound healing experiments. High-MW quaternary ammonium-chitosan conjugates bearing thiol groups on their chains were more effective in promoting cell migration than the non-thiolated conjugates and the chitosan chlorhydrate. Moreover, they significantly improve wound healing process compared to untreated cells. According to the present in vitro preliminary results, high MW thiolated quaternary ammonium-chitosan conjugates can be considered good candidates for the management of wounds.

Effects of poly(amidoamine) dendrimers on the structure and function of key blood components

Poly(amidoamine) dendrimers have a variety of promising biomedical applications; however, the biological safety of the dendrimers has not been well clarified. This study focuses on the effects of poly(amidoamine) dendrimers (G3, G4, G5, G5–OH) on the structure and function of key blood components, in order to elucidate the impacts of the dendrimers on the aggregation, morphology, lysis of human red blood cells, structural and conformational change as well as polymerization of fibrinogen, and the coagulation of blood tissue. The poly(amidoamine) dendrimers caused aggregation, morphological changes, and lysis of red blood cells, depending on the dendrimer concentration, generation, and surface functional groups. All the dendrimers induced fibrinogen structural and conformational changes, but only cationic dendrimers impaired fibrinogen polymerization ability at high concentrations. In addition, the cationic dendrimers inhibited the activity of clotting factors and fibrinogen in the coagulation of whole blood. Therefore, the surface functional groups, generation, and concentration of the dendrimers play important roles in affecting the structure and function of key blood components. These results provide a critical theoretical basis for the molecular design and clinical application of the poly(amidoamine) dendrimers.