A two-step method of cyclolinopeptide (linusorb) preparation from flaxseed cake via dry-screening.

Linusorbs (LO), cyclolinopeptides, are a group of cyclic hydrophobic peptides and considered a valuable by-product of flaxseed oil due to numerous health benefits. Currently applied acetone or methanol extraction could contaminate the feedstocks for further food-grade application. Using flaxseed cake as feedstock, this study established a practical method for preparing LO from pressed cake. Firstly, LO composition of 15 flaxseed cultivars was analyzed. Next, cold-pressed cake was milled and screened mechanically. The kernel and hull fractions were separated based on the disparity of their mechanical strength. Monitored by hyperspectral fluorescence, the LO-enriched kernel fraction separated from cold-pressed flaxseed cake was further used as feedstock for LO production. After ethanol extraction, partition, and precipitation, LOs were extracted from cold-pressed flaxseed cake with a purity of 91.4%. The proposed method could serve as feasible flaxseed cake valorization strategy and enable the preparation of other polar compounds such as flax lignan and mucilage.

Protective effect of Inonotus obliquus polysaccharide on mice infected with Neospora caninum.

The study aimed to explore the protective effects of Inonotus obliquus polysaccharide (IOP) on Neospora caninum (N. caninum) infection. Our data showed that the survival rate of the mice was the highest and the survival time was the longest when the IOP was 2 mg/10 g. In agreement with these observations, IOP alleviated the pathological damage in the various organs and tissues of the mice. Compared with that in the Neosporidium infection model group, the content of N. caninum in the heart, liver, spleen, lung, kidney and brain, determined through HE staining, was significantly lower. In addition, IOP inhibited the levels of immunoglobulin G1 (IgG1) and immunoglobulin G2 (IgG2a) from the 21st to 42nd day of the administration group, whereas the levels of interleukin-12 (IL-12) and serum tumor necrosis factor alpha (TNF-α) were down-regulated at 7 d - 42 d. The production of CD4+ T lymphocytes was promoted, the number of CD8+ T lymphocytes were significantly lower and the CD4+/CD8+ ratio was significantly elevated. Furthermore, IOP effectively balanced the levels of hormones including gonadotropin-releasing hormone (GnRH), luteotropic hormone (LH) and testosterone (T) in male mice, and progesterone (PROG), estradiol (E2) and prolactin (PRL) in female mice. These findings demonstrate that IOP exerts protective effects against pathological damage caused by N. caninum infection in mice, and improve the immune function of the organism and regulate the secretion balance of sex hormones.

Anatomical Prior and Inter-Slice Consistency for Semi-Supervised Vertebral Structure Detection in 3D Ultrasound Volume.

Three-dimensional (3D) ultrasound imaging technique has been applied for scoliosis assessment, but the current assessment method only uses coronal projection images and cannot illustrate the 3D deformity and vertebra rotation. The vertebra detection is essential to reveal 3D spine information, but the detection task is challenging due to complex data and limited annotations. We propose VertMatch to detect vertebral structures in 3D ultrasound volume containing a detector and classifier. The detector network finds the potential positions of structures on transverse slice globally, and then the local patches are cropped based on detected positions. The classifier is used to distinguish whether the patches contain real vertebral structures and screen the predicted positions from the detector. VertMatch utilizes unlabeled data in a semi-supervised manner, and we develop two novel techniques for semi-supervised learning: 1) anatomical prior is used to acquire high-quality pseudo labels; 2) inter-slice consistency is used to utilize more unlabeled data by inputting multiple adjacent slices. Experimental results demonstrate that VertMatch can detect vertebra accurately in ultrasound volume and outperforms state-of-the-art methods. Moreover, VertMatch is also validated in automatic spinous process angle measurement on forty subjects with scoliosis, and the results illustrate that it can be a promising approach for the 3D assessment of scoliosis.

Development of Automatic Assessment Framework for Spine Deformity Using Freehand 3-D Ultrasound Imaging System.

A 3-D ultrasound (US) imaging technique has been studied to facilitate the diagnosis of spinal deformity without radiation. The objective of this article is to propose an assessment framework to automatically estimate spinal deformity in US spine images. The proposed framework comprises four major components, a US spine image generator, a novel transformer-based lightweight spine detector network, an angle evaluator, and a 3-D modeler. The principal component analysis (PCA) and discriminative scale space tracking (DSST) method are first adopted to generate the US spine images. The proposed detector is equipped with a redundancy queries removal (RQR) module and a regularization item to realize accurate and unique detection of spine images. Two clinical datasets, a total of 273 images from adolescents with idiopathic scoliosis, are used for the investigation of the proposed framework. The curvature is estimated by the angle evaluator, and the 3-D mesh model is established by the parametric modeling technique. The accuracy rate (AR) of the proposed detector can be achieved at 99.5%, with a minimal redundancy rate (RR) of 1.5%. The correlations between automatic curve measurements on US spine images from two datasets and manual measurements on radiographs are 0.91 and 0.88, respectively. The mean absolute difference (MAD) and standard deviation (SD) are 2.72° ± 2.14° and 2.91° ± 2.36° , respectively. The results demonstrate the effectiveness of the proposed framework to advance the application of the 3-D US imaging technique in clinical practice for scoliosis mass screening and monitoring.

Superhydrophilic Poly(2-hydroxyethyl methacrylate) Hydrogel with Nanosilica Covalent Coating: A Promising Contact Lens Material for Resisting Tear Protein Deposition and Bacterial Adhesion.

Tear protein deposition and bacterial adhesion are the main drawbacks of the hydrogel contact lens. In this study, we developed a novel superhydrophilic poly(2-hydroxyethyl methacrylate) (NSCC-pHEMA) hydrogel with nanosilica covalent coating by the combination of colloidal silica immersion and dehydration treatment. The infrared spectroscopy and energy dispersive X-ray spectroscopy analyses confirmed the successful formation of Si-O covalent bonding between nanosilica and pHEMA hydrogel. This coating was highly stable against powerful sonication or long-term shaking immersion treatment. Among various NSCC-pHEMA hydrogels with different colloidal silica concentrations, the 7%NSCC-pHEMA hydrogel generated a superhydrophilic micro wrinkle surface with a root-mean-square roughness of 43.10 nm, which dramatically reduced the deposition of lysozyme and bovine serum albumin by 65% and 57%, respectively, and decreased the adhesion of S. aureus and E. coli by 59% and 66%, respectively, in comparison to the pHEMA hydrogel. However, the nanosilica coating had little effect on the mechanical properties, light transmittance, oxygen permeability, and equilibrium water content of the pHEMA hydrogel. NSCC-pHEMA hydrogels were nontoxic to both mouse fibroblasts (L929) and human immortalized keratinocytes (HaCaT). Thus, the superhydrophilic NSCC-pHEMA hydrogel is a potential contact lens material for resisting tear protein deposition and bacterial adhesion.

A calcium hydroxide/oleic acid/phospholipid nanoparticle induced cancer cell apoptosis by the combination of intracellular calcium overload and lactic acidosis elimination.

Intracellular calcium ions (Ca2+) influence the proliferation-apoptosis balance, and lactic acidosis is an innate feature of a malignant tumor. In this study, a calcium hydroxide/oleic acid/phospholipid nanoparticle [CUR-Ca(OH)2-OA/PL NP] with lipase/pH dual responsive delivery of Ca2+ and curcumin (CUR) was developed for inducing cancer cell apoptosis by a combination of intracellular calcium overload and lactic acidosis elimination. The nanoparticle showed a core-shell structure with some good performance, including an adequate nano-size, negative charge, good blood circulation stability, and non-hemolysis. MDA-MB-231 breast cancer cells exhibited a higher lipase activity than A549 human lung adenocarcinoma cells and L929 mouse fibroblasts by fluorescence analysis. CUR-Ca(OH)2-OA/PL NPs were highly internalized by MDA-MB-231 cells, intracellularly released CUR and Ca2+, triggered the activation of caspase 3 and caspase 9, and caused apoptosis by intracellular calcium overload via a mitochondrial-mediated pathway. Lactic acid of 20 mM inhibited the apoptosis of MDA-MB-231 cells depending on the glucose insufficiency level, but this inhibition could be eliminated by CUR-Ca(OH)2-OA/PL NPs, leading to nearly complete apoptosis. Herein, CUR-Ca(OH)2-OA/PL NPs are a potential killer of cancer cells with high lipase activity by a combination of intracellular calcium overload and lactic acidosis elimination.

[Cloning and gene function of dicarboxylate-tricarboxylate carrier protein in Gastrodia elata].

The gene GeDTC encoding the dicarboxylate-tricarboxylate carrier protein in Gastrodia elata was cloned by specific primers which were designed based on the transcriptome data of G. elata. Bioinformatics analysis on GeDTC gene was carried out by using ExPASY, ClustalW, MEGA, etc. Positive transgenic plants and potato minituber were obtained by virtue of the potato genetic transformation system. Agronomic characters, such as size, weight, organic acid content, and starch content, of potato minituber were tested and analyzed and GeDTC gene function was preliminarily investigated. The results showed that the open reading frame of GeDTC gene was 981 bp in length and 326 amino acid residues were encoded, with a relative molecular weight of 35.01 kDa. It was predicted that the theoretical isoelectric point of GeDTC protein was 9.83, the instability coefficient was 27.88, and the average index of hydrophilicity was 0.104, which was indicative of a stable hydrophilic protein. GeDTC protein had a transmembrane structure and no signal peptide and was located in the inner membrane of mitochondria. The phylogenetic tree showed that GeDTC was highly homologous with DTC proteins of other plant species, among which GeDTC had the highest homology with DcDTC(XP＿020675804.1) in Dendrobium candidum, reaching 85.89%. GeDTC overexpression vector pCambia1300-35Spro-GeDTC was constructed by double digests, and transgenic potato plants were obtained by Agrobacterium-mediated gene transformation. Compared with the wild-type plants, transgenic potato minituber harvested by transplanting had smaller size, lighter weight, lower organic acid content, and no significant difference in starch content. It is preliminarily induced that GeDTC is the efflux channel of tricarboxylate and related to the tuber development, which lays a foundation for further elucidating the molecular mechanism of G. elata tuber development.

Poly(2-hydroxyethyl methacrylate-co-quaternary ammonium salt chitosan) hydrogel: A potential contact lens material with tear protein deposition resistance and antimicrobial activity.

Tear protein deposition resistance and antimicrobial property are two challenges of conventional poly(2-hydroxyethyl methacrylate) (pHEMA) contact lenses. In this work, we developed a poly(2-hydroxyethyl methacrylate-co-quaternary ammonium salt chitosan) hydrogel, named as p(HEMA-co-mHACC) hydrogel, using acryloyl HACC (mHACC) as a macromolecular crosslinker. With increasing the acryloyl substitution degree (14-29%) or mHACC content (2-11%), the hydrogel showed an enhanced tensile strength (432-986 kPa) and Young's modulus (360-1158 kPa), a decreased elongation at break (242-84%), and an increased visible light transmittance (0-95%). At an optimal acryloyl substitution degree of 26%, with the increase of mHACC content from 2% to 11%, p(HEMA-co-mHACC) hydrogel presented a decreased water contact angle from 84.6 to 55.3 degree, an increased equilibrium water content from 38% to 45%, and an enhanced oxygen permeability from 8.5 to 13.5 barrer. Due to the enhancement in surface hydrophilicity and electropositivity, p(HEMA-co-mHACC) hydrogel remarkably reduced the deposition of lysozyme, but little affected the adsorption of BSA, depending on the hydrophilic/hydrophobic and electrostatic interactions. The antimicrobial test against Staphylococcus aureus and Escherichia coli showed that p(HEMA-co-mHACC) hydrogel presented an 8-32 times higher germicidal ability than pHEMA hydrogel, indicative of a better antimicrobial activity. The in vitro cell culture of mouse NIH3T3 fibroblasts and immortalized human keratinocytes showed that p(HEMA-co-mHACC) hydrogel was non-toxic. Thus, p(HEMA-co-mHACC) hydrogel with tear protein deposition resistance and antimicrobial activity is a potential candidate for contact lenses.

Oxymatrine screened from Sophora flavescens by cell membrane immobilized chromatography relieves histamine-independent itch.

OBJECTIVES: This study aimed to discover the active compounds of Sophora flavescens Ait. (SF), the anti-itch effects and underlying mechanisms of oxymatrine (OMT), one of the bioactive compounds from SF. METHODS: Dorsal root ganglion cell membrane immobilized chromatography was used to screen potential anti-pruritic active compounds from SF. The scratching behaviour was analysed to systematically study the anti-pruritic effects of OMT in chloroquine- (CQ), peptide Ser-Leu-Ile-Gly-Arg-Leu- (SLIGRL), histamine- (HIS) and allyl-isothiocyanate-(AITC)-induced itch mice models. Real-time quantitative PCR, in-vivo study and molecular docking were employed to explore the underlying mechanisms. KEY FINDINGS: All in all, 21 compounds of SF were identified and 5 potential bioactive compounds were discovered. OMT significantly reduced scratching bouts in two HIS-independent itch models induced by CQ and SLIGRL but was not effective in the HIS-induced itch model. OMT reduced scratching bouts in a dose-dependent manner and decreased the messenger RNA (mRNA) expression of transient receptor potential ankyrin 1 (TRPA1) channel in two HIS-independent itch models; in addition, OMT reduced the wipes and scratching bouts induced by AITC. CONCLUSIONS: This study discovered five potential anti-pruritic compounds including OMT in the SF extract, and OMT has strong anti-pruritic effects in HIS-independent itch via TRPA1 channel.

ATP/Hyals dually responsive core-shell hyaluronan/chitosan-based drug nanocarrier for potential application in breast cancer therapy.

The stability of self-assembled drug nanocarriers during blood circulation and the controlled intracellular drug delivery are two challenges in cancer therapy. In this paper, we constructed an adenosine triphosphate (ATP)/hyaluronidase(Hyals) dually responsive core-shell hyaluronan/chitosan-based drug nanocarrier for breast cancer therapy, using SNX-loaded 3-fluoro-4-carboxyphenylboronic acid-conjugated quaternary ammonium chitosan nanoparticles (SNX@HTCC-FPBA NPs) as the core and crosslinked polyethylene glycol-/methacrylate-modified hyaluronic acid (mHA-PEG) as the shell. The formed SNX@HTCC-FPBA/mHA-PEG NPs were stable against salt ion strength, pH values and human plasma mimicking the bloodstream, but ATP/Hyals dually sensitive with a drug delivery of 85% within 48 h in the mimicking intracellular environment of breast cancer cells. These nanoparticles showed a low hemolysis of less than 3%, a high resistance to bovine serum albumin adsorption of 0.06 mg/mg, and an efficient internalization by two breast cancer cell lines (MCF-7 and MDA-MB-453). The cell culture indicated that they were friendly to human skin fibroblasts, but presented a close IC50 value to SNX for MCF-7 (0.14 µg mL-1) and MDA-MB-453 (0.05 µg mL-1) at 48 h, respectively. Thus, SNX@HTCC-FPBA/mHA-PEG NPs were potential drug nanocarriers for breast tumor therapy.

Hydroxypropyl cellulose enhanced ionic conductive double-network hydrogels.

Ionic conductive hydrogels with both high-performance in conductivity and mechanical properties have received increasing attention due to their unique potential in artificial soft electronics. Here, a dual physically cross-linked double network (DN) hydrogel with high ionic conductivity and tensile strength was fabricated by a facile approach. Hydroxypropyl cellulose (HPC) biopolymer fibers were embedded in a poly (vinyl alcohol)­sodium alginate (PVA/SA) hydrogel, and then the prestretched PVA-HPC/SA composite hydrogel was immersed in a CaCl2 solution to prepare PVA-HPCT/SA-Ca DN hydrogels. The obtained composite hydrogel has an excellent tensile strength up to 1.4 MPa. Importantly, the synergistic effect of hydroxypropyl cellulose (HPC) and prestretching reduces the migration resistance of ions in the hydrogel, and the conductivity reaches 3.49 S/ m. In addition, these composite hydrogels are noncytotoxic, and they have a low friction coefficient and an excellent wear resistance. Therefore, PVA-HPCT/SA-Ca DN hydrogels have potential applications in nerve replacement materials and biosensors.

An alginate/poly(N-isopropylacrylamide)-based composite hydrogel dressing with stepwise delivery of drug and growth factor for wound repair.

Anti-inflammation and angiogenesis play an essential role in wound healing. In this study, we developed a composite hydrogel dressing with stepwise delivery of diclofenac sodium (DS) and basic fibroblast growth factor (bFGF) in the inflammation stage and new tissue formation stage respectively for wound repair. Sodium alginate (SA) crosslinked by calcium ion acted as the continuous phase, and thermosensitive bFGF-loaded poly(N-isopropylacrylamide) nanogels (pNIPAM NGs, LCST1 ~33 °C) and DS-loaded p(N-isopropylacrylamide-co-acrylic acid) nanogels [p(NIPAM-co-AA) NGs, LCST2 ~40 °C] acted as the dispersed phase. The synthesized SA/bFGF@pNIPAM/DS@p(NIPAM-co-AA) hydrogel presented a desirable storage modulus of ~4500 Pa, a high water equilibrium swelling ratio of ~90, an appropriate water vapor transmission rate of ~2300 g/m2/day, and nontoxicity to human skin fibroblasts. The in vitro thermosensitive cargo delivery of this hydrogel showed that 92% of DS was sustainably delivered at 37 °C within the early three days mimicking the inflammation stage, while 80% of bFGF was controlled released at 25 °C within the later eight days mimicking new tissue formation stage. The in vivo wound healing of rats showed that this composite hydrogel presented a better healing effect with a wound contraction of 96% at 14 d, less inflammation and higher angiogenesis, than all control groups. These findings indicate SA/bFGF@pNIPAM/DS@p(NIPAM-co-AA) composite hydrogel is a potential dressing for wound repair.

Poly(2-hydroxyethyl methacrylate)/ß-cyclodextrin-hyaluronan contact lens with tear protein adsorption resistance and sustained drug delivery for ophthalmic diseases.

A series of poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels containing cross-linked ß-cyclodextrin-hyaluronan (ß-CD-crHA), with tear protein adsorption resistance and sustained drug delivery, were developed as contact lens materials for eye diseases. ß-CD-HA was synthesized from aminated ß-CD and HA and then crosslinked within pHEMA hydrogel using polyethylenimine as a crosslinker. The synthesized ß-CD-HA was characterized by 1H NMR analysis, and ß-CD-crHA immobilized in pHEMA hydrogel was confirmed by FT-IR, SEM, and AFM analyses. The incorporation of ß-CD-crHA significantly improved the surface hydrophilicity, water uptake ability, oxygen permeability, and flexibility of pHEMA hydrogel, but did not compromise light transmission. pHEMA/ß-CD-crHA hydrogels not only decreased the tear protein adsorption because of the electrostatically mutual repulsion and the improved hydrophilicity, leading to the reduced adhesion of Staphylococcus aureus on the hydrogel surface, but also enhanced the encapsulation capacity and the sustainable delivery of diclofenac due to the formation of inclusion complexes between ß-CD and drugs. All the hydrogels were nontoxic to 3T3 mouse fibroblasts by in vitro cell viability analysis. Among these hydrogels with different ß-CD-crHA contents, pHEMA/ß-CD-crHA10 hydrogel showed the lowest water contact angle of 52 °, the highest water content of 65%, the largest Dk value of 36.4 barrer, and the optimal modulus of 1.8 MPa, as well as a good light transmission of over 90%. The in vivo conjunctivitis treatment of rabbits for 72 h indicated that drug-loaded pHEMA/ß-CD-crHA10 hydrogel presented a better therapeutic effect than both one dose administration of drug solution per day and drug-loaded pHEMA hydrogel. Thus, pHEMA/ß-CD-crHA10 hydrogel is a promising contact lens material for ophthalmic diseases. STATEMENT OF SIGNIFICANCE: Topical eye drops are currently the most popular treatment for ophthalmic diseases, but frequent dosing is necessary to acquire the desirable clinical effect at the expense of systemic side-effects. Drug-loaded contact lenses, as an alternative of eye drops, possess many good performances and show potential applications. However, the sustained drug delivery and the tear protein adsorption resistance are still challenging for contact lenses. Hence, we developed a novel pHEMA/ß-CD-crHA hydrogel by incorporating ß-CD-crHA crosslinked network into pHEMA hydrogel. Besides the improvements in surface hydrophilicity, water uptake ability, oxygen permeability, and flexibility, pHEMA/ß-CD-crHA hydrogel also reduced the adsorption of tear proteins and the adhesion of Staphylococcus aureus, enhanced the drug encapsulation, and prolonged the drug delivery, with better effect in the conjunctivitis treatment of rabbits. Thus, pHEMA/ß-CD-crHA hydrogel is a potential contact lens material for treating ophthalmic diseases.

CaCO3 nanoparticles pH-sensitively induce blood coagulation as a potential strategy for starving tumor therapy.

Based on the concept of starving tumor therapy, in this study we put forward a new idea that the pH-sensitive Ca2+ delivery of calcium carbonate nanoparticles (CaCO3 NPs) induced blood coagulation of tumor vessels, and first explored the effect of CaCO3 NPs on the in vitro and in vivo blood coagulation by acid stimulus. CaCO3 NPs with a size of about 100 nm and a porous structure of several nanometers were synthesized in an emulsion system, which showed a high loading capacity (49%) of doxorubicin hydrochloride (DOX) with an encapsulation efficiency of 98% and a pH-sensitive drug delivery. The hemolysis test showed that CaCO3 NPs were blood compatible. The in vitro Ca2+ delivery and blood clotting tests indicated that CaCO3 NPs pH-sensitively released Ca2+, and caused rapid blood coagulation at pH 5.0 but no thrombus at pH 7.4. Confocal laser scanning microscopy showed that after uptake by MCF-7 or MDA-MB-231 breast cancer cells, CaCO3 NPs mainly distributed in endosomes/lysosomes within the initial 2 h and then decomposed by acid stimulus, leading to the intracellular delivery of Ca2+ that subsequently migrated outside the cells. CaCO3 NPs were nontoxic to NIH3T3 mouse fibroblasts, but highly toxic to both MCF-7 and MDA-MB-231 cells after loading DOX. After topical administration into the breast tumors of mice, CaCO3 NPs evoked significant thrombosis and hemorrhage of tumor vasculature by hematoxylin-eosin and Masson's trichrome staining. These results indicated that CaCO3 NPs could induce blood coagulation via acid stimulus, showing potential applications in blocking tumor vessels for starving tumor therapy.

Analgesic and antipruritic effects of oxymatrine sustained-release microgel cream in a mouse model of inflammatory itch and pain.

BACKGROUND: Allergic contact dermatitis (ACD) is a highly prevalent inflammatory and immune skin disease accompanied with persistent pruritus and pain. Oxymatrine (OMT) exhibits antipruritic and anti-inflammatory effects in squaric acid dibutyl ester (SADBE) induced ACD mice model, but the need for frequent administration stipulated by short half-life and low bioavailability limits clinical application. OBJECTIVE: To evaluate the analgesic and antipruritic effects of OMT gel (OG), OMT sustained release microgel powder (OMP) and OMT sustained release microgel cream (OMC) in SADBE induced ACD mice, with subsequent study of the mechanism and side effects (irritation) of optimal dosage form. METHOD: On day 11, the thickness of the right cheek skin of mice was measured and mice spontaneous behaviors were recorded for 1.5 h. In the OMC experiment, hematoxylin-eosin and toluidine blue staining were performed on the cheek skin, and the irritation of OMC was tested on the back skin of rabbits. Blood analyzer was used to measure the counts of inflammatory cells in peripheral blood. The mRNA expressions of IL-1ß, TNF-α, CXCR3, CXCL10, IL-6, IL-10, IL-17A and IL-31 in cheek skin, TRPA1 and TRPV1 channels in trigeminal ganglion (TG), IFN-γ in spleen and IL-17A in thymus were measured by RT-qPCR. RESULTS: OMC, OMP and OG significantly decreased wipes and scratching bouts, alleviated skin inflammation. OMC required less frequent administration and is easier to apply, while its antipruritic effect was stronger than the analgesic effect. OMC rescued the deficits in epidermal keratinization and inflammatory cell infiltration, decreased the leukocyte count in peripheral blood, had no irritation to the broken rabbit's skin. Furthermore, OMC significantly down-regulated the mRNA expression of IL-1ß, TNF-α, CXCR3, CXCL10, IL-6, IL-10, IL-17A and IL-31 in cheek skin, TRPA1 and TRPV1 channels in TG, IFN-γ in thymus and IL-17A in spleen. CONCLUSION: We have demonstrated that OMC exhibits advanced analgesic, antipruritic and anti-inflammatory effects when compared with OG and OMP in ACD mice by regulating inflammation, chemokines, immune mediators and inhibiting the mRNA expression of TRPA1 and TRPV1. OMC has no irritation to the intact and damaged skin of rabbits.

Nano-hydroxyapatite enhanced double network hydrogels with excellent mechanical properties for potential application in cartilage repair.

Hydrogels with desirable characteristics have been supposed to be potential materials for cartilage repair. However, the biomechanical, biotribological and biocompatible properties of hydrogels remain some crucial challenges. To address these challenges, we developed a dual physically cross-linked poly (vinyl alcohol)-(nano hydroxyapatite)/(2-hydroxypropyltrimethyl ammonium chloride chitosan) (PVA-HA/HACC-Cit) hydrogels with double-network (DN) through a simply freezing/thawing technique and an immersing process. The DN hydrogel with an optimized HA concentration exhibited outstanding fracture tensile stress (2.70 ± 0.24 MPa), toughness (14.09 ± 2.06 MJ/m3) and compressive modulus (0.88 ± 0.09 MPa). In addition, the PVA-HA/HACC-Cit DN hydrogels demonstrated remarkable anti-fatigue property, extraordinary self-recovery and energy dissipation ability due to their unique dual physically cross-linked structures. Moreover, the low friction coefficient, the predominant wear resistance property, as well as the excellent cytocompatibility were realized for the DN hydrogels because of the existence of nano-hydroxyapatite. Thus, this work puts forward a new strategy in the preparation of DN hydrogels for promising applications in cartilage repair.

Chitosan derivative-based double network hydrogels with high strength, high fracture toughness and tunable mechanics.

Physically cross-linked double-network (DN) hydrogels are capturing more and more attention due to their good mechanical properties and self-recovery ability. However, they usually suffer from complicated preparation process and fussy performance regulation, which severely limit their applications in many fields. Herein, we fabricated a physically cross-linked poly(vinyl alcohol)-(2-hydroxypropyltrimethyl ammonium chloride chitosan) (PVA-HACC) DN hydrogels without organic solvents or toxic cross-linking agents via a simple two-step method of freezing/thawing and immersion processing. The effects of immersion time and concentration of Na3Cit solution on the structures and mechanical properties of the hydrogels were investigated. The obtained hydrogels exhibited excellent mechanical properties including high elastic modulus (1.44 MPa), high strength (a maximal tensile fracture stresses of 4.14 MPa and a maximal compressive stresses of over 70 MPa at 98% strain), and superior fracture toughness (17.09 MJ/m3). In addition, good self-recovered property and anti-fatigue performance were realized for the hydrogels owing to the reversible HACC ionic networks. The preparation of PVA-HACC DN hydrogels offers a new guidance for the design and synthesis of environmentally friendly DN hydrogels with outstanding mechanical properties and broad application prospects.

Pulmonary delivery of therapeutic proteins based on zwitterionic chitosan-based nanocarriers for treatment on bleomycin-induced pulmonary fibrosis.

Nanoparticle-based pulmonary delivery of protein therapeutics provides a promising approach for improving protein bioavailability to treat either local or systemic diseases, however high-efficient nanocarrier is a great challenge. Here, biomimetic phosphorylcholine-chitosan nanoparticles (PCCs-NPs) taking advantages of both zwitterionic phosphorylcholine and chitosan were developed as a pulmonary protein delivery platform. msFGFR2c, a potential therapeutic protein for lung fibrosis as model was loaded into PCCs-NPs via ionic gelation. The obtained msFGFR2c/PCCs-NPs inhibited α-SMA expression in fibroblasts induced by TGF-ß1, slightly more effective than naked msFGFR2c. After orotracheal administration to bleomycin-induced pulmonary fibrosis model rats, msFGFR2c/PCCs-NPs resulted in a significant antifibrotic efficacy, with reduction in inflammatory cytokines and α-SMA expression, remarkable attenuation of lung fibrosis score and collagen deposition, and significant increase in survival rate, while naked msFGFR2c exhibited a poor efficacy. The in vitro and in vivo results strongly indicated that PCCs-NPs may be a promising nanocarrier for pulmonary protein delivery.

Anti-biofouling and functionalizable bioinspired chitosan-based hydrogel coating via surface photo-immobilization.

Zwitterionic polymer is a new generation of anti-fouling materials with its good resistance to protein and bacterial adhesion. Constructing the anti-fouling surfaces with zwitterionic polymer has been regarded as an effective approach for improving the biocompatibility and biofunctionality of clinic devices. Herein, we reported a facile approach to construct a biodegradable anti-biofouling and functionalizable hydrogel coating via photo-immobilization using commercial polyethylene terephthalate (PET) films as the substrate, based on zwitterionic glycidyl methacrylate-phosphorylcholine-chitosan (PCCs-GMA). The surface structure and physicochemical properties of zwitterionic PCCs-GMA hydrogel coating were investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and static water contact angle measurement, and its functionalizable sites were detected by fluorescence labeling. Compared with the pristine PET and cationic chitosan - GMA and hydroxypropyltrimethyl ammonium chloride chitosan (HTCC) - GMA hydrogel coatings, zwitterionic PCCs-GMA hydrogel coating exhibited excellent biocompatibility, and significantly reduced protein adsorption for three model proteins of fibrinogen, immunoglobulin and lysozyme, repelled platelet adhesion, as well as showed a high resistance to bacterial attachment of Escherichia coli and Staphylococcus aureus and superior anti-fouling properties to MRC-5 cells. The results indicated that photo-immobilized zwitterionic PCCs-GMA hydrogel coating has perspective as a dual functional platform with integrated antifouling and further biofunctional properties for various biomedical applications.

Chitosan derivative-based self-healable hydrogels with enhanced mechanical properties by high-density dynamic ionic interactions.

Chitosan derivative-based self-healable hydrogels with enhanced mechanical properties are reported, which were prepared by polymerization of acrylic acid (AAc) in 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) solution. The PAAc/HACC hydrogels exhibit tensile fracture stress as high as 3.31 MPa and a Young's modulus of 2.53 MPa. They can maintain their original shape after 30 repeated compression cycles under various strain conditions, with a compression stress of more than 60 MPa at 99% strain. The damaged PAAc/HACC hydrogels can heal together in the presence of a NaCl salt solution with a self-healing efficiency of up to 61%. In addition, the PAAc/HACC hydrogels have high ionic conductivity and can serve as electrolytes for supercapacitors. The analysis suggests that all these good properties of the PAAc/HACC hydrogels mainly result from their high-density dynamic ionic interactions structure.