Homogalacturonan from squash: Characterization and tau-binding pattern of a sulfated derivative.

A pectic polysaccharide (WAP) was isolated from squash and identified as a homogalacturonan with a molecular mass of 83.2 kDa by GPC, monosaccharide composition analysis, FT-IR and NMR spectra. Sulfation modification of WAP was carried out and a sulfated derivative (SWAP) was obtained with a substitution degree of 1.81. The NMR spectrum indicated that the sulfation modification mainly occurred at the C-2 and C-3 positions of galacturonan residues. The binding pattern of SWAP to tau K18 protein was observed in 2D 1H15N HSQC spectra of tau, which resembled the tau-heparin interaction, with R2 domain as the major binding region. These results suggest that SWAP has the potential to act as a heparin mimic to inhibit the transcellular spread of tau; thus natural polysaccharide from squash may be developed into therapies for AD and related tauopathies.

Enhanced Antiviral Function of Magnesium Chloride-Modified Heparin on a Broad Spectrum of Viruses.

Previous studies reported on the broad-spectrum antiviral function of heparin. Here we investigated the antiviral function of magnesium-modified heparin and found that modified heparin displayed a significantly enhanced antiviral function against human adenovirus (HAdV) in immortalized and primary cells. Nuclear magnetic resonance analyses revealed a conformational change of heparin when complexed with magnesium. To broadly explore this discovery, we tested the antiviral function of modified heparin against herpes simplex virus type 1 (HSV-1) and found that the replication of HSV-1 was even further decreased compared to aciclovir. Moreover, we investigated the antiviral effect against the new severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and measured a 55-fold decreased viral load in the supernatant of infected cells associated with a 38-fold decrease in virus growth. The advantage of our modified heparin is an increased antiviral effect compared to regular heparin.

Dual-Targeting Glycol Chitosan/Heparin-Decorated Polypyrrole Nanoparticle for Augmented Photothermal Thrombolytic Therapy.

Near-infrared (NIR)-light-modulated photothermal thrombolysis has been investigated to overcome the hemorrhage danger posed by clinical clot-busting substances. A long-standing issue in thrombosis fibrinolytics is the lack of lesion-specific therapy, which should not be ignored. Herein, a novel thrombolysis therapy using photothermal disintegration of a fibrin clot was explored through dual-targeting glycol chitosan/heparin-decorated polypyrrole nanoparticles (GCS-PPY-H NPs) to enhance thrombus delivery and thrombolytic therapeutic efficacy. GCS-PPY-H NPs can target acidic/P-selectin high-expression inflammatory endothelial cells/thrombus sites for initiating lesion-site-specific thrombolysis by hyperthermia using NIR irradiation. A significant fibrin clot-clearance rate was achieved with thrombolysis using dual-targeting/modality photothermal clot disintegration in vivo. The molecular level mechanisms of the developed nanoformulations and interface properties were determined using multiple surface specific analytical techniques, such as particle size distribution, zeta potential, electron microscopy, Fourier-transform infrared spectroscopy (FTIR), wavelength absorbance, photothermal, immunofluorescence, and histology. Owing to the augmented thrombus delivery of GCS-PPY-H NPs and swift treatment time, dual-targeting photothermal clot disintegration as a systematic treatment using GCS-PPY-H NPs can be effectively applied in thrombolysis. This novel approach possesses a promising future for thrombolytic treatment.

Electrospun fibers based on botanical, seaweed, microbial, and animal sourced biomacromolecules and their multidimensional applications.

This review summarizes and broadly classifies all of the major sustainable natural carbohydrate bio-macromolecular manifestations in nature - from botanical (cellulose, starch, and pectin), seaweed (alginate, carrageenan, and agar), microbial (bacterial cellulose, dextran, and pullulan), and animal (hyaluronan, heparin, chitin, and chitosan) sources - that have been contrived into electrospun fibers. Furthermore, a relative study of these biomaterials for the fabrication of nanofibers by electrospinning and their characteristics viz. solution behavior, blending nature, as well as rheological and fiber attributes are discussed. The potential multidimensional applications of nanofibers (filtration, antimicrobial, biosensor, gas sensor, energy storage, catalytic, and tissue engineering) originating from these polysaccharides and their major impacts on the properties, functionalities, and uses of these electrospun fibers are compared and critically examined.

Effective Inhibition of SARS-CoV-2 Entry by Heparin and Enoxaparin Derivatives.

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has caused a pandemic of historic proportions and continues to spread globally, with enormous consequences to human health. Currently there is no vaccine, effective therapeutic, or prophylactic. As with other betacoronaviruses, attachment and entry of SARS-CoV-2 are mediated by the spike glycoprotein (SGP). In addition to its well-documented interaction with its receptor, human angiotensin-converting enzyme 2 (hACE2), SGP has been found to bind to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we pseudotyped SARS-CoV-2 SGP on a third-generation lentiviral (pLV) vector and tested the impact of various sulfated polysaccharides on transduction efficiency in mammalian cells. The pLV vector pseudotyped SGP efficiently and produced high titers on HEK293T cells. Various sulfated polysaccharides potently neutralized pLV-S pseudotyped virus with clear structure-based differences in antiviral activity and affinity to SGP. Concentration-response curves showed that pLV-S particles were efficiently neutralized by a range of concentrations of unfractionated heparin (UFH), enoxaparin, 6-O-desulfated UFH, and 6-O-desulfated enoxaparin with 50% inhibitory concentrations (IC50s) of 5.99 µg/liter, 1.08 mg/liter, 1.77 µg/liter, and 5.86 mg/liter, respectively. In summary, several sulfated polysaccharides show potent anti-SARS-CoV-2 activity and can be developed for prophylactic as well as therapeutic purposes.IMPORTANCE The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in Wuhan, China, in late 2019 and its subsequent spread to the rest of the world has created a pandemic situation unprecedented in modern history. While ACE2 has been identified as the viral receptor, cellular polysaccharides have also been implicated in virus entry. The SARS-CoV-2 spike glycoprotein (SGP) binds to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we report structure-based differences in antiviral activity and affinity to SGP for several sulfated polysaccharides, including both well-characterized FDA-approved drugs and novel marine sulfated polysaccharides, which can be developed for prophylactic as well as therapeutic purposes.

Amphiphilic multi-charged cyclodextrins and vitamin K co-assembly as a synergistic coagulant.

Balancing and neutralizing heparin dosing after surgeries and hemodialysis treatment is of great importance in medical and clinical fields. In this study, a series of new amphiphilic multi-charged cyclodextrins (AMCD)s as anti-heparin coagulants were designed and synthesized. The AMCD assembly was capable of selective heparin binding through multivalent bonding and showed a better neutralizing effect towards both unfractionated heparin and low molecular weight heparin than protamine in plasma. Meanwhile, an AMCD and vitamin K (VK) co-assembly was prepared to realize heparin-responsive VK release and provide a novel VK deficiency treatment for hemodialysis patients. This AMCD-VK co-assembly for heparin neutralization & vitamin K supplementation synergistic coagulation represents a promising candidate as a clinical anti-heparin coagulant.

Analysis of Heparan sulfate/heparin from Colla corii asini by liquid chromatography-electrospray ion trap mass spectrometry.

Colla corii asini (CCA) made from donkey-hide has been widely used as a health-care food and an ingredient of traditional Chinese medicine. Heparan sulfate (HS)/heparin is a structurally complex class of glycosaminoglycans (GAGs) that have been implicated in a wide range of biological activities. However, their presence within CCA, and their possible structural characteristics, were previously unknown. In this study, GAG fractions containing HS/heparin were isolated from CCA and their disaccharide compositions were analyzed by high sensitivity liquid chromatography-ion trap/time-of-flight mass spectrometry (LC-MS-ITTOF). This revealed that, in addition to the eight commonly seen HS disaccharides, the four rare N-unsubstituted disaccharides were also detected in significant quantities. The disaccharide compositions varied significantly between HS/heparin fractions indicating chains with differing domain structures. This novel structural information may lead to a better understanding of the biological activities (i.e. anticoagulation and antitumor action) of CCA.

Biomimetic engineering endothelium-like coating on cardiovascular stent through heparin and nitric oxide-generating compound synergistic modification strategy.

Co-immobilization of two or more molecules with different and complementary functions to prevent thrombosis, suppress smooth muscle cell (SMC) proliferation, and support endothelial cell (EC) growth is generally considered to be promising for the re-endothelialization on cardiovascular stents. However, integration of molecules with distinct therapeutic effects does not necessarily result in synergistic physiological functions due to the lack of interactions among them, limiting their practical efficacy. Herein, we apply heparin and nitric oxide (NO), two key molecules of the physiological functions of endothelium, to develop an endothelium-mimetic coating. Such coating is achieved by sequential conjugation of heparin and the NO-generating compound selenocystamine (SeCA) on an amine-bearing film of plasma polymerized allylamine. The resulting surface combines the anti-coagulant (anti-FXa) function provided by the heparin and the anti-platelet activity of the catalytically produced NO. It also endows the stents with the ability to simultaneously up-regulate α-smooth muscle actin (α-SMA) expression and to increase cyclic guanylate monophosphate (cGMP) synthesis of SMC, thereby significantly promoting their contractile phenotype and suppressing their proliferation. Importantly, this endothelium-biomimetic coating creates a favorable microenvironment for EC over SMC. These features impressively improve the antithrombogenicity, re-endothelialization and anti-restenosis of vascular stents in vivo.

Selective Inhibition of PAR4 (Protease-Activated Receptor 4)-Mediated Platelet Activation by a Synthetic Nonanticoagulant Heparin Analog.

Objective- PAR4 (protease-activated receptor 4), one of the thrombin receptors in human platelets, has emerged as a promising target for the treatment of arterial thrombotic disease. Previous studies implied that thrombin exosite II, known as a binding site for heparin, may be involved in thrombin-induced PAR4 activation. In the present study, a heparin octasaccharide analog containing the thrombin exosite II-binding domain of heparin was chemically synthesized and investigated for anti-PAR4 effect. Approach and Results- PAR4-mediated platelet aggregation was examined using either thrombin in the presence of a PAR1 antagonist or γ-thrombin, which selectively activates PAR4. SCH-28 specifically inhibits PAR4-mediated platelet aggregation, as well as the signaling events downstream of PAR4 in response to thrombin. Moreover, SCH-28 prevents thrombin-induced ß-arrestin recruitment to PAR4 but not PAR1 in Chinese Hamster Ovary-K1 cells using a commercial enzymatic complementation assay. Compared with heparin, SCH-28 is more potent in inhibiting PAR4-mediated platelet aggregation but has no significant anticoagulant activity. In an in vitro thrombosis model, SCH-28 reduces thrombus formation under whole blood arterial flow conditions. Conclusions- SCH-28, a synthetic small-molecular and nonanticoagulant heparin analog, inhibits thrombin-induced PAR4 activation by interfering with thrombin exosite II, a mechanism of action distinct from other PAR4 inhibitors that target the receptor. The characteristics of SCH-28 provide a new strategy for targeting PAR4 with the potential for the treatment of arterial thrombosis.

Chemical characterization and complement modulating activities of an arabinogalactan-protein-rich fraction from an aqueous extract of avocado leaves.

The aim of this study was to chemically characterize an arabinogalactan-protein-rich fraction (FRAGP) obtained from an aqueous extract of avocado leaves and investigate its effects on the classical pathway of the complement system. The FRAGP contained 4.6% ±â€¯1.8%, 22.5% ±â€¯4.9%, and 76.7% ±â€¯8.8% of total protein, arabinogalactan-protein, and carbohydrates, respectively. Arabinose and galactose were the main monosaccharide constituents. FT-IR and NMR data, together with linkage analyses, indicated the presence of a structure that included a (1 → 3)-linked ß-D-Galp main chain, mainly substituted at O-6 by Gal and Ara residues, which was characteristic of a type II arabinogalactan. The effect of FRAGP on the classical pathway of complement system was examined by a hemolytic fixation test and comparing with heparin, which was used as a control for inhibition. With pre-incubation, the IC50 of FRAGP was 1.90 ±â€¯1.1 µg/mL, which was similar to that of heparin (IC50 = 2.90 ±â€¯0.3 µg/mL). Without pre-incubation, the IC50 values were 18.6 ±â€¯3.7 and 8.0 ±â€¯4.1 µg/mL for FRAGP and heparin, respectively. Collectively, these results suggested that FRAGP has an inhibitory effect on the classical pathway of the complement system.

Heparin-stabilized gold nanoparticles-based CUPRAC colorimetric sensor for antioxidant capacity measurement.

Sensing of total antioxidant capacity (TAC) as an integrated parameter showing the collective action of various antioxidants is an important challenge in food, biochemical and drug analysis. A novel heparin-stabilized gold nanoparticles (AuNPs)-based 'cupric reducing antioxidant capacity' (CUPRAC) colorimetric sensor was designed for TAC measurement. Heparin, a sulfated polysaccharide, was both the reducing and stabilizing agent for distinct negatively-charged AuNPs synthesis. The stabilized AuNPs were added to the copper(I)-neocuproine (Cu(I)-Nc) solution formed from the reaction of Cu(II)-Nc with antioxidants, and the absorbance of the resulting Cu(I)-Nc-AuNPs (Cu(I)-Nc cationic chelate electrostatically adsorbed on gold nanoparticles) was measured at 455 nm. As opposed to other similar AuNPs-based sensors, the proposed nano-sensor exhibited excellent (1000-fold) tolerance toward inert electrolytes without aggregation. The linear range was wider than that of conventional CUPRAC, with lower LOD (0.2 µM for trolox) and higher molar absorptivity (8.36â€¯× 104 M-1 cm-1 for quercetin). The 'trolox equivalent antioxidant capacity' (TEAC) values and activity order for a number of antioxidants were in accordance with those of the reference CUPRAC assay. Antioxidant additions to black tea extract gave recoveries of 93-97% and RSD 2-6%. This green sensor significantly reduced reagent consumption, and operated in complex food samples with a simple, reliable and robust methodology.

Comparison of Barricor™ vs. lithium heparin tubes for selected routine biochemical analytes and evaluation of post centrifugation stability.

INTRODUCTION: Obtaining suitable results unaffected by pre- or postanalytical phases is pivotal for clinical chemistry service. We aimed comparison and stability of nine biochemical analytes after centrifugation using Barricor™ plasma tubes with mechanical separator vs standard Vacutainer® lithium heparin tubes. MATERIALS AND METHODS: We collected samples on six healthy volunteers and nine patients from intensive care units into 6 mL plastic Vacutainer® lithium heparin tubes and 5.5 mL plastic Barricor™ plasma tubes. All tubes were centrifuged within 30 minutes after venipuncture. First, we compared results of nine biochemical analytes from lithium heparin tubes with Barricor™ tubes for each analyte using Passing-Bablok and Bland-Altman analyses. Second, we calculated the difference of analyte concentrations between baseline and time intervals in tubes stored at + 4 °C. Based on the total change limit we calculated the maximum allowable concentrations percentage change from baseline. RESULTS: The majority of correlation coefficients were close to 0.99 indicating good correlation in the working range. Bland-Altman analyses showed an acceptable concordance for all analytes. In consequence, the Barricor™ tube might be an alternative to regular lithium heparin tube. Stability with this new generation tube is improved for eight analytes (except for aspartate aminotransferase) in comparison with regular lithium heparin tubes. CONCLUSIONS: By using Barricor™ tubes and prompt centrifugation, supplemental analysis or re-analysis for eight analytes including alanine aminotransferase, alkaline phosphatase, C-reactive protein, high sensitivity troponin T, lactate dehydrogenase, NT-pro BNP, potassium and sodium could be performed within 72 h of specimen collection.

Design of Carrageenan-Based Heparin-Mimetic Gel Beads as Self-Anticoagulant Hemoperfusion Adsorbents.

The currently used hemoperfusion adsorbents such as activated carbon and ion-exchange resin show dissatisfactory hemocompatibility, and a large dose of injected heparin leads to the increasing cost and the risk of systematic bleeding. Natural polysaccharide adsorbents commonly have good biocompatibility, but their application is restricted by the poor mechanical strength and low content of functional groups. Herein, we developed an efficient, self-anticoagulant and blood compatible hemoperfusion adsorbent by imitating the structure and functional groups of heparin. Carrageenan and poly(acrylic acid) (PAA) cross-linked networks were built up by the combination of phase inversion of carrageenan and post-cross-linking of AA, and the formed dual-network structure endowed the beads with improved mechanical properties and controlled swelling ratios. The beads exhibited low protein adsorption amounts, low hemolysis ratios, low cytotoxicity, and suppressed complement activation and contact activation levels. Especially, the activated partial thromboplastin time, prothrombin time, and thrombin time of the gel beads were prolonged over 13, 18, and 4 times than those of the control. The self-anticoagulant and biocompatible beads showed good adsorption capacities toward exogenous toxins (560.34 mg/g for heavy metal ions) and endogenous toxins (14.83 mg/g for creatinine, 228.16 mg/g for bilirubin, and 18.15 mg/g for low density lipoprotein (LDL)), thus, highlighting their potential usage for safe and efficient blood purification.

Unidirectional BMP2-loaded collagen scaffolds induce chondrogenic differentiation.

Microfracture surgery may be improved by the implantation of unidirectional collagen scaffolds that provide a template for mesenchymal stem cells to regenerate cartilage. Incorporation of growth factors in unidirectional scaffolds may further enhance cartilage regeneration. In scaffolds, immobilization of growth factors is required to prolong in vivo activity, to limit diffusion and to reduce the amount of growth factor needed for safe clinical application. We investigated the immobilization of bone morphogenetic protein 2 (BMP2) to unidirectional collagen scaffolds and the effect on in vitro chondrogenesis. C3H10T1/2 cells were seeded on unidirectional collagen scaffolds with and without covalently attached heparin, and with and without incubation with BMP2 (1 and 10 µg), or with BMP2 present in the culture medium (10-200 ng ml-1). Culturing was for 2 weeks and readout parameters included histology, immunohistochemistry, biochemical analysis and molecular biological analysis. The unidirectional pores facilitated the distribution of C3H10T1/2 cells and matrix formation throughout scaffolds. The effective dose of medium supplementation with BMP2 was 100 ng ml-1 (total exposure 1 µg BMP2), and similar production of cartilage-specific molecules chondroitin sulfate (CS) and type II collagen was found for scaffolds pre-incubated with 10 µg BMP2. Pre-incubation with 1 µg BMP2 resulted in less cartilage matrix formation. The conjugation of heparin to the scaffolds resulted in more CS and less type II collagen deposition compared to scaffolds without heparin. In conclusion, unidirectional collagen scaffolds pre-incubated with 10 µg BMP2 supported chondrogenesis in vitro and may be suitable for prolonged cartilage matrix synthesis in vivo.

Effect of different lipid apheresis methods on plasma polyunsaturated fatty acids.

Lipoprotein apheresis has been shown to improve the cardiovascular outcome in patients with atherosclerotic disease and therapy-refractory hypercholesterolemia or elevated lipoprotein (a) (Lp(a)). An elevated intake of omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has also been associated with a reduced cardiovascular risk. However, until now only little is known about the effect of apheresis treatment on the levels of omega-6 and omega-3 polyunsaturated fatty acids (n-6 PUFA and n-3 PUFA) in patients. Using gas chromatography (GC) the present study analyzed the content of n-6 and n-3 PUFA as well as saturated fatty acids and monounsaturated fatty acids in the plasma of 20 patients with hyperlipidemia undergoing regular lipoprotein apheresis procedures in direct pre- and post-therapy measurements. Lipoprotein apheresis uniformly reduced the concentrations of arachidonic acid (AA), EPA and DHA fatty acids analyzed in the plasma. However, the three different apheresis methods analyzed (heparin precipitation, membrane filtration and direct absorption) had different effects on the fatty acid profile in the plasma. We found that heparin precipitation and direct absorption apheresis procedures led to a significant decrease of plasma n-3 and n-6 PUFA by 40-50%. In contrast, patients undergoing membrane filtration apheresis, levels pre- and post-apheresis did not change significantly, with AA and EPA being only reduced by approximately 10% while levels of DHA were maintained pre- and post-apheresis. In contrast, total triglyceride levels were lowered most potently by membrane filtration apheresis. In summary, heparin precipitation and direct absorption apheresis approaches significantly lowered polyunsaturated fatty acids in plasma, while membrane filtration did not. This might have implications for cardiovascular and inflammatory risk/benefit profiles associated with n-6 and n-3 PUFA levels in the body.

Analysing the bioactive makeup of demineralised dentine matrix on bone marrow mesenchymal stem cells for enhanced bone repair.

Dentine matrix has proposed roles for directing mineralised tissue repair in dentine and bone; however, the range of bioactive components in dentine and specific biological effects on bone-derived mesenchymal stem cells (MSCs) in humans are less well understood. The aims of this study were to further elucidate the biological response of MSCs to demineralised dentine matrix (DDM) in enhancing wound repair responses and ascertain key contributing components. Dentine was obtained from human teeth and DDM proteins solubilised with ethylenediaminetetraacetic acid (EDTA). Bone marrow derived MSCs were commercially obtained. Cells with a more immature phenotype were then selected by preferential fibronectin adhesion (FN-BMMSCs) for use in subsequent in vitro assays. DDM at 10 µg/mL reduced cell expansion, attenuated apoptosis and was the minimal concentration capable of inducing osteoblastic differentiation. Enzyme-linked immunosorbent assay (ELISA) quantification of growth factors indicated physiological levels produced the above responses; transforming growth factor ß (TGF-ß1) was predominant (15.6 ng/mg DDM), with relatively lower concentrations of BMP-2, FGF, VEGF and PDGF (6.2-4.7 ng/mg DDM). Fractionation of growth factors from other DDM components by heparin affinity chromatography diminished osteogenic responses. Depletion of biglycan from DDM also attenuated osteogenic potency, which was partially rescued by the isolated biglycan. Decorin depletion from DDM had no influence on osteogenic potency. Collectively, these results demonstrate the potential of DDM for the delivery of physiological levels of growth factors for bone repair processes, and substantiate a role for biglycan as an additional adjuvant for driving osteogenic pathways.

Effects of oolonghomobisflavan A on oxidation of low-density lipoprotein.

Oxidation of low-density lipoprotein (LDL) by reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been suggested to be involved in the onset of atherosclerosis. Oolong tea contains unique polyphenols including oolonghomobisflavan A (OFA). In this study, the effects of OFA on LDL oxidation by ROS and RNS were investigated in vitro. OFA suppressed formation of cholesterol ester hydroperoxides in LDL oxidized by peroxyl radical and peroxynitrite, and formation of thiobarbituric acid reactive substances in LDL oxidized by Cu2+. In addition, OFA inhibited fragmentation, carbonylation, and nitration of apolipoprotein B-100 (apo B-100) in the oxidized LDL, in which heparin-binding activity of apo B-100 was protected by OFA. Our results suggest that OFA exhibits antioxidant activity against both lipid peroxidation and oxidative modification of apo B-100 in LDL oxidized by ROS and RNS. Polyphenols in oolong tea may prevent atherosclerosis by reducing oxidative stress.

Emergent Molecular Recognition through Self-Assembly: Unexpected Selectivity for Hyaluronic Acid among Glycosaminoglycans.

Oligophenylenevinylene (OPV)-based fluorescent (FL) chemosensors exhibiting linear FL responses toward polyanions were designed. Their application to FL sensing of glycosaminoglycans (heparin: HEP, chondroitin 4-sulfate: ChS, and hyaluronic acid: HA) revealed that the charge density encoded as the unit structure directs the mode of OPV self-assembly: H-type aggregate for HEP with 16-times FL increase and J-type aggregate for HA with 93-times FL increase, thus unexpectedly achieving the preferential selectivity for HA in contrast to the conventional HEP selective systems. We have found that the integral magnitude of three factors consisting of binding mechanism, self-assembly, and FL response can amplify the structural information on the target input into the characteristic FL output. This emergent property has been used for a novel molecular recognition system that realizes unconventional FL sensing of HA, potentially applicable to the clinical diagnosis of cancer-related diseases.

The effect of SDF-1α on low dose BMP-2 mediated bone regeneration by release from heparinized mineralized collagen type I matrix scaffolds in a murine critical size bone defect model.

The treatment of critical size bone defects represents a challenge. The growth factor bone morphogenetic protein 2 (BMP-2) is clinically established but has potentially adverse effects when used at high doses. The aim of this study was to evaluate if stromal derived factor-1 alpha (SDF-1α) and BMP-2 released from heparinized mineralized collagen type I matrix (MCM) scaffolds have a cumulative effect on bone regeneration. MCM scaffolds were functionalized with heparin, loaded with BMP-2 and/or SDF-1α and implanted into a murine critical size femoral bone defect (control group, low dose BMP-2 group, low dose BMP-2 + SDF-1α group, and high dose BMP-2 group). After 6 weeks, both the low dose BMP-2 + SDF-1α group (5.8 ± 0.6 mm³, p = 0.0479) and the high dose BMP-2 group (6.5 ± 0.7 mm³, p = 0.008) had a significantly increased regenerated bone volume compared to the control group (4.2 ± 0.5 mm³). There was a higher healing score in the low dose BMP-2 + SDF-1α group (median grade 8; Q1-Q3 7-9; p = 0.0357) than in the low dose BMP-2 group (7; Q1-Q3 5-9) histologically. This study showed that release of BMP-2 and SDF-1α from heparinized MCM scaffolds allows for the reduction of the applied BMP-2 concentration since SDF-1α seems to enhance the osteoinductive potential of BMP-2. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2126-2134, 2016.

ALD mediated heparin grafting on nitinol for self-expanded carotid stents.

Carotid-artery atherosclerosis is a common cause of ischemic stroke. Carotid-artery stenting (CAS) is one of the most effective treatments. However, In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent which affect clinical safety and reduce effects. In this study, atomic layer deposition (ALD) technology was applied to deposit a layer (10nm) of Al2O3 on Nitinol surface as an intermediate functional layer. The alumina covered surface was then modified with a coupling agent 3-aminopropyltriethoxysilane (APS) and heparin sequentially in order to improve the hemocompatibility of Nitinol stents. The successful graft of APS and heparin onto Nitinol was proven by X-ray photoelectron spectroscopy. Furthermore, the predicted improvement in the biocompatibilities of modified Nitinol was confirmed by water contact angle measurement, protein adsorption, platelet adhesion, and plasma recalcification time determination. The results of hemolysis assay, cell proliferation and cytotoxicity tests revealed that the grafting of heparin on NiTi kept the original positive performance of nitinol material. The results indicate that ALD technology is of great potential for the manufacture of medical devices, especially for surface modifications and functionalization. ALD technology can help with modifications of inert metallic surfaces and therefore benefit implantable medical devices, especially intravascular stents.