A biodegradable soy protein isolate-based waterborne polyurethane composite sponge for implantable tissue engineering.

A biodegradable soy protein isolate-based waterborne polyurethane composite sponge (SWPU) was prepared from soy protein isolate (SPI) and polyurethane prepolymer (PUP) by a process involving chemical reaction and freeze-drying. Effects of SPI content (0, 10%, 30%, 50%, 70%) on the micro-structure and physical properties of the composite sponges were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The results showed that the reaction between -NCO of PUP and -NH2 of SPI formed porous SPI-based WPU composite sponges. The results of the water absorption ratio measurement, solvent resistance measurement and compressive testing showed that water absorption, hydrophilicity, and tensile strength in the dry state of the composite sponges increased with the increase of SPI content. Especially, the tensile strength ranged from 0.3 MPa to 5.5 MPa with the increase in SPI content. The cytocompatibility and biodegradability of the composite sponges were evaluated by in vitro cell culture and in vivo implantation experiments. The results indicated that a certain SPI content in the sponges could promote the adhesion, growth, and proliferation of cells, enhance the cytocompatibility and accelerate the degradation speed of composite sponges. During the in vivo implanting period within 9 months, SWPU-50 sponge containing 50% of SPI brought out the lowest activated inflammatory reaction, most newly-regenerated blood capillaries, and best histocompatibility. All results indicated that SWPU-50 composite sponges had greatest potential for tissue engineering.

[Advance of new dressings for promoting skin wound healing].

As a temporary skin substitute, the dressings can protect the wound, stop bleeding, prevent infection and contribute to wound healing. According to the characteristics of the materials, wound dressings can be classified into traditional wound dressings, interactive dressings, bioactive dressings, tissue engineering dressings and smart dressings, etc. Different dressings have different characteristics, and some products have been widely used in clinic. Recently nanomaterials and three-dimensional bio-printing technology have significantly improved the performance of wound dressings. Future dressings will be developed from single function to multi-function composite, and integrated into an intelligent one. This paper reviews the current research progress and future development prospects of wound dressings.

Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect.

Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide conduits in the field of nerve tissue engineering.

The application of polyetheretherketone (PEEK) implants in cranioplasty.

Cranioplasty is a challenge to neurosurgeons, especially considering protection of intracranial contents. In recent years, material choice for cranioplasty is still controversial, which brings complexity to this seemingly straightforward procedure. PEEK, a tough, rigid, biocompatible material, has been used more recently in cranioplasty to provide better protection. The aim of this review is to summarize the outcome of research conducted on the material for cranioplasty applications. We also reviewed the comparison of PEEK with several common materials in previous articles. This is also the most complete data review article at present. In addition, the combination of nano-materials and PEEK is also a hotspot of research, so we have made a careful review of this aspect. We also summarized our own experience, telling about the future prospects of PEEK in the field of clinical cranioplasty should be highlighted. Improving the bioactivity, porosity, thinning, biocompatibility, antibacterial ability, integration and cost reduction of PEEK implants without affecting their mechanical properties is a major challenge.

Strategies on Nanodiagnostics and Nanotherapies of the Three Common Cancers.

The emergence of nanomedicine has enriched the knowledge and strategies of treating diseases, and especially some incurable diseases, such as cancers, acquired immune deficiency syndrome (AIDS), and neurodegenerative diseases. The application of nanoparticles in medicine is in the core of nanomedicine. Nanoparticles can be used in drug delivery for improving the uptake of poorly soluble drugs, targeted delivery to a specific site, and drug bioavailability. Early diagnosis of and targeted therapies for cancers can significantly improve patients' quality of life and extend patients' lives. The advantages of nanoparticles have given them a progressively important role in the nanodiagnosis and nanotherapy of common cancers. To provide a reference for the further application of nanoparticles, this review focuses on the recent development and application of nanoparticles in the early diagnosis and treatment of the three common cancers (lung cancer, liver cancer, and breast cancer) by using quantum dots, magnetic nanoparticles, and gold nanoparticles.

Green Fabrication of Amphiphilic Quaternized ß-Chitin Derivatives with Excellent Biocompatibility and Antibacterial Activities for Wound Healing.

Bacterial infection has always been a great threat to public health, and new antimicrobials to combat it are urgently needed. Here, a series of quaternized ß-chitin derivatives is prepared simply and homogeneously in an aqueous KOH/urea solution, which is a high-efficiency, energy-saving, and "green" route for the modification of chitin. The mild reaction conditions keep the acetamido groups of ß-chitin intact and introduce quaternary ammonium groups on the primary hydroxyl at the C-6 position of the chitin backbone, allowing the quaternized ß-chitin derivatives (QCs) to easily form micelles. These QCs are found to exhibit excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and Rhizopus oryzae with minimum inhibitory concentrations (MICs) of 8, 12, 60, and 40 µg mL-1 , respectively. As a specific highlight, their inherent outstanding biocompatibility and significant accelerating effects on the healing of uninfected, E. coli-infected, and S. aureus-infected wounds imply that these novel polysaccharide-based materials can be used as dressings for clinical skin regeneration, particularly for infected wounds.

Electrodeposition to construct mechanically robust chitosan-based multi-channel conduits.

A series of electrodeposited chitosan-based multi-channel conduits (ECMC) with potential for peripheral nerve tissue engineering were constructed using a novel electrodeposition method combined with homemade molds. The structural and mechanical properties of the ECMC were characterized by scanning electron microscopy, Fourier-transformed infrared spectroscopy, X-ray diffraction patterns and mechanical testing. The results showed that the electrodeposition process did not change the chemical structure of the chitosan molecules, but endowed the ECMC with high levels of flexibility and elasticity. Hemocompatibility and cytocompatibility of the ECMC were evaluated by hemolysis assay, MTT assay and live/dead assay. The results indicated that the ECMC had a low hemolysis rate, and can promote cell proliferation and support cell adhesion. This work provides a safe and feasible electrodeposition method to construct chitosan-based conduits with potential applications for peripheral nerve tissue engineering.

Advance of DNA and CCPs-based nanocarriers in drug delivery systems.

Development of smart and functional polymeric carriers, which enable controlled or timed release of a bioactive material, thereby providing a better dosing pattern and minimizing side effects, becomes a new requirement in the field of drug delivery. In the recent few decades, a great many advancements of polymer synthetic methods have led to a new generation of bioactive polymers' applications as drug controlled release carriers. In this review, we focus on the use of bioactive polymers for drug delivery system, with a particular in the utility of DNA-based nanocarriers and cell-penetrating peptides (CCPs)-based nanocarriers to provide precision control for drug targeting or stimuli responsive systems.

Cellulose/soy protein composite-based nerve guidance conduits with designed microstructure for peripheral nerve regeneration.

OBJECTIVE: The objective of this work was to develop nerve guidance conduits from natural polymers, cellulose and soy protein isolate (SPI), by evaluating the effects of cellulose/SPI film-based conduit (CSFC) and cellulose/SPI sponge-based conduit (CSSC) on regeneration of nerve defects in rats. APPROACH: CSFC and CSSC with the same chemical components were fabricated from cellulose and SPI. Effects of CSSC and CSFC on regeneration of the defective nerve were comparatively investigated in rats with a 10 mm long gap in sciatic nerve. The outcomes of peripheral nerve repair were evaluated by a combination of electrophysiological assessment, Fluoro-Gold retrograde tracing, double NF200/S100 immunofluorescence analysis, toluidine blue staining, and electron microscopy. The probable molecular mechanism was investigated using quantitative real-time PCR (qPCR) analysis. MAIN RESULTS: Compared with CSFC, CSSC had 2.69 times higher porosity and 5.07 times higher water absorption, thus ensuring much higher permeability. The nerve defects were successfully bridged and repaired by CSSC and CSFC. Three months after surgery, the CSSC group had a higher compound muscle action potential amplitude ratio, a higher percentage of positive NF200 and S100 staining, and a higher axon diameter and myelin sheath thickness than the CSFC group, showing the repair efficiency of CSSC was higher than that of CSFC. qPCR analysis indicated the mRNA levels of nerve growth factor, IL-10, IL-6, and growth-associated protein 43 (GAP-43) were higher in the CSSC group. This also indicated that there was better nerve repair with CSSC due to the higher porosity and permeability of CSSC providing a more favourable microenvironment for nerve regeneration than CSFC. SIGNIFICANCE: A promising nerve guidance conduit was developed from cellulose/SPI sponge that showed potential for application in the repair of nerve defect. This work also suggests that nerve guidance conduits with better repair efficiency could be developed through structure design and processing optimization.

Improvement in physical and biological properties of chitosan/soy protein films by surface grafted heparin.

A series of chitosan/soy protein isolate (SPI) composite films (CS-n, n=0, 10 and 30, corresponding to SPI content in the composites) were prepared. Heparin was grafted onto the surface of CS-n to fabricate a series of heparinized films (HCS-n). CS-n and HCS-n were characterized by ATR-Fourier transform infrared spectroscopy and water contact angle. The surface heparin density was measured by toluidine blue assay. The results showed that heparin has been successfully grafted onto the surface of CS-n. Heparin evenly distributed on the surface of the films and the heparin content increased with the increase of SPI content, and the hydrophilicity of the films was enhanced due to the grafted heparin. The cytocompatibility and hemocompatibility of CS-n and HCS-n were evaluated by cell culture (MTT assay, live/dead assay, cell morphology and cell density observation), platelet adhesion test, plasma recalcification time (PRT) measurement, hemolysis assay and thrombus formation test. HCS-n showed higher cell adhesion rate and improved cytocompatibility compared to the corresponding CS-n. HCS-n also exhibited lower platelet adhesion, longer PRT, higher blood anticoagulant indexes (BCI) and lower hemolysis rate than the corresponding CS-n. The improved cytocompatibility and hemocompatibility of HCS-n would shed light on the potential applications of chitosan/soy protein-based biomaterials that may come into contact with blood.

[Effect of L-methionine on trace elements in lead-intoxicated mice].

OBJECTIVE: To investigate the effect of L-methionine (L-Met) on the content of Zn, Cu, Mn, Fe in liver, brain, spleen and kidney of lead intoxicated mice. METHODS: Distilled water was given to 10 mice (normal control group) and lead acetate solution of 400 micro g/ml Pb(2+) to 20 mice to serve as drinking water for 10 days. The lead administration was then withdrawn and lead exposed mice were randomly divided into two groups: the lead control group took distilled water as drinking water for 4 weeks to serve as positive control, the other one took L-Met solution (0.5 mg/ml) as drinking water for 4 weeks (Pb + L-Met group) to serve as the treatment group. All the animals were sacrificed on the 1st day after 4 weeks, and the contents of Zn, Cu, Fe, Mn, Pb in liver, brain, spleen and kidney were measured by Inductively Coupled Plasma (ICP) Emission Spectrometry. RESULTS: Lead contents in liver, brain, spleen and kidney of Pb control group [(1.490 +/- 1.654) micro g/g, (3.470 +/- 2.757) micro g/g, (4.975 +/- 2.993) micro g/g, (0.066 +/- 0.001) micro g/g respectively], were higher than those in normal control group [(0.015 +/- 0.001) micro g/g, (0.009 +/- 0.007) micro g/g, (0.027 +/- 0.002) micro g/g, (0.006 +/- 0.015) micro g/g, P < 0.05] while Zn contents in liver, brain, spleen and Fe and Mn content in liver, brain, spleen and kidney in Pb control group were lower than those in normal control group (P < 0.05). Pb contents of brain, spleen and Cu content of kidney in Pb + L-Met group were higher than those in normal control group (P < 0.05). Zn contents of liver, brain, spleen, Fe contents of liver, brain, spleen, kidney, and Mn contents of brain, spleen in Pb + L-Met group were lower than those in normal control group (P < 0.05). Fe contents of liver, brain, Zn content of spleen, Cu content of kidney and Mn contents of liver, brain, spleen in the Pb + L-Met group were higher than those in the Pb control group (P < 0.05). The lead levels of four organs in the Pb + L-Met group were lower than those in the Pb control group (P < 0.05). CONCLUSION: Lead could be eliminated by L-Met, which may affect the distribution and metabolism of trace elements in mice.

Quantum dot-based immunofluorescent imaging of Ki67 and identification of prognostic value in HER2-positive (non-luminal) breast cancer.

BACKGROUND: The immunohistochemical assessment of Ki67 antigen (Ki67) is the most widely practiced measurement of breast cancer cell proliferation; however, it has some disadvantages and thus the prognostic value of Ki67 in breast cancer remains controversial. Our previous studies confirmed the advantages of quantum dots-based nanotechnology for quantitative analysis of biomarkers compared with conventional immunohistochemistry (IHC). This study was designed to assess Ki67 by quantum dot-immunohistochemistry (QD-IHC) and investigate the prognostic value of the Ki67 score in human epidermal growth factor receptor 2 (HER2)-positive (non-luminal) breast cancer. METHODS: Ki67 expression in 108 HER2-positive (non-luminal) breast cancer specimens was detected by IHC and QD-IHC. Two observers assessed the Ki67 score independently and comparisons between the two methods were made. The prognostic value of the Ki67 score for five-year disease-free survival was estimated. RESULTS: The same antigen localization, high correlation of staining rates (r=0.993), and high agreement of measurements (κ=0.874) of Ki67 expression (cutoff: 30%) in breast cancer were found by QD-IHC and conventional IHC. The QD-IHC had a better interobserver agreement for the Ki67 score than conventional IHC (t=-7.280, P<0.01). High Ki67 expression (cutoff: 30%) was associated with shorter disease-free survival (log-rank test; IHC, P=0.026; QD-IHC, P=0.001), especially in the lymph node-negative subgroups (log-rank test; IHC, P=0.017; QD-IHC, P=0.002). CONCLUSION: QD-IHC imaging of Ki67 was an easier and more accurate method for detecting and assessing Ki67. The Ki67 score was an independent prognosticator in the HER2-positive (non-luminal) breast cancer patients.

Effect of blood-retinal barrier development on formation of selenite nuclear cataract in rat.

Selenite cataract, as an experimental animal model of nuclear cataract to mimic human senile cataract, is produced only when overdose selenite is injected to neonatal rats before eyelid opening. To clarify the cause of age differences on selenite cataract formation in rats, mRNA expression of GPx1, MsrA and MsrB1, as well as GPx activity in Wistar rat lens at different ages were assayed, level of lipid peroxidation, extent of lens damage induced by sodium selenite and barricade function of blood-retinal barrier (BRB) were investigated. The results showed that mRNA expressions and activity of antioxidant enzymes in neonatal rat lens before eyelid opening were the highest and then decreased with age, and revealed by transmission electron microscopy (TEM) using lanthanum hydroxide as tracer that higher selenite content entering eyes injured lens and resulted in cataract formation for immature BRB before eyelid opening, moreover, a little selenite content entering eyes was not enough to induce cataract formation after eyelid opening because of mature BRB.

[Clonning and expression of procalcitonin and preparation of its polyclonal antibody].

OBJECTIVE: To clone, express the procalcitonin (PCT) and prepare its polyclonal antibody. METHODS: We designed 10 DNA primers according to the encoding sequence of human PCT gene from GenBank, amplified PCT gene by PCR and constructed the recombinant vector pGEX-KG-PCT. Then the fusion protein, PCT-GST, was expressed in E.coli and purified by affinity chromatography. The corresponding polyclonal antibody was produced in the New Zealand white rabbits immunized with the fusion protein, and its biological activity was detected by Western blotting. The specificity and titer of the polyclonal antibody was identified by agar gel immunodiffusion test. RESULTS: We successfully obtained the full-length PCT gene and expressed the fusion PCT-GST in E.coli. SDS-PAGE showed that relative molecular mass (Mr;) was about 36 000. Agar gel immunodiffusion test revealed that the prepared polyclonal antibody could specially recognized PCT and its titer was 1:4. CONCLUSION: The PCT is successfully cloned, expressed and purified. The high specific polyclonal antibody of PCT is prepared.

Effect of soybean-lecithin as an enhancer of buccal mucosa absorption of insulin.

OBJECTIVE: Transmucosal delivery is a suitable route for insulin non-injection administration. In order to understand how insulin passes through mucosa with soybean-lecithin as an enhancing absorption. METHODS: The penetration rate of insulin molecular through porcine buccal mucosa was investigated by measuring transbuccal fluxes in the Ussing Chambers. The imaging morphology of rabbits buccal mucosa was analyzed by using non-contact mode atomic force microscopy. RESULTS: The permeation rate can be increased by co-administration of soybean-lecithin. Untreated buccal mucosa showed relatively smooth surface characteristics, with many small crater-like pits and indentations spread over mucosa surfaces. Buccal mucosa that had been treated with 1.0% (w/v) sodium deoxycholic acid (pH 7.4) appeared to much more indentations characteristic, which treated with 2.5% (w/v) soybean-lecithin (pH 7.4) and 2.5% (w/v) Azone or laurocapram (pH 7.4) appeared rather different, the surface mucosa treated with soybean-lecithin emulsion showed a fine, rippling effect whereas those exposed to Azone display a more coarse, undulating surface feature. As a result of that Azone could damage the surface of the buccal mucosa, but soybean-lecithin could not. CONCLUSION: This study demonstrated that soybean-lecithin is a better and safer enhancer for insulin transmucosal delivery.

Hypoglycaemic effect of a novel insulin buccal formulation on rabbits.

Transmucosal delivery is a suitable route for insulin non-injection administration. In this study, the hypoglycaemic effect of INSULIN BUCCAL SPRAY (IBS), a formulation with soybean lecithin and propanediol combined as absorption enhancer for insulin on diabetic rabbits and rats, were investigated. The hypoglycaemic rate was calculated and the pharmacodynamics and pharmacokinetics of the formulation in rabbits were studied. The results show that when the diabetic rabbits were administrated with IBS in dosages of 0.5, 1.5 and 4.5Ukg(-1), the blood glucose level decreased significantly compared with that of the control group and the hypoglycaemic effect lasted over 5h. The blood glucose decreasing rates are 22.4, 48.1 and 53.5%, respectively. The average bioavailability of IBS by buccal delivery versus subcutaneous injection is 29.2%. Meanwhile, the diabetic rats were administrated with IBS in dosages of 1.0, 3.0 and 9.0Ukg(-1), the blood glucose level decreased significantly compared with that of the control group and the hypoglycaemic effect lasted over 4h. The blood glucose decreasing rates are 24.6, 47.5 and 59.6%, respectively. Furthermore, the penetration of fluorescein isothiocyanate (FITC)-labelled insulin through rabbit buccal mucosa was investigated by scanning the distribution of the fluorescent probe in the epithelium using confocal laser scanning microscopy. The results revealed that FITC-insulin can pass through the buccal mucosa promoted by the enhancer and the passage of insulin across the epithelium includes both intracellular and paracellular routes. From the rabbit and rat experimental results showed that IBS is an effective buccal delivery system, which is promising for clinical trial and the future clinical application.