Biomimetic Hemostatic Powder Derived from Coacervate-Immobilized Thermogelling Copolymers.

Intrinsic hemostasis is an innate body response to prevent bleeding based on the sol-gel transition of blood. However, it is often inadequate for exceptional situations, such as acute injury and coagulation disorders, which typically require immediate medical intervention. Herein, we report the preparation of an efficient hemostatic powder, composed of tannic acid (TA), poly(ethylene glycol) (PEG), and poly(d,l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) triblock copolymer (TB), for biomimetic hemostasis at the bleeding sites. TA has a high affinity for biomolecules and cells and can form coacervates with PEG driven by hydrogen bonding. TB enhances the mechanical strength and provides thermoresponsiveness. The hemostatic powder can rapidly transit into a physical and biodegradable seal on wet substrates under physiological conditions, demonstrating its promise for the generation of instant artificial clots. Importantly, this process is independent of the innate blood clotting process, which could benefit those with blood clotting disorders. This biomimetic hemostatic powder is an adaptive topical sealing agent for noncompressible and irregular wounds, which is promising for biomedical applications.

Comparison of alveolar bone width and sagittal tooth angulation of maxillary central incisors in Class I and Class III canine relationships: a retrospective study using CBCT.

BACKGROUND: Canine relationship is a key reference identifying anterior malocclusion and an important implication for evaluating preimplantation bone morphology at maxillary esthetic zone. This study aimed to compare the differences of maxillary central incisor-related measurements (alveolar bone thickness and tooth sagittal angulation) between Class I and Class III canine relationship and further explore the risk factors for immediate implant placement in the anterior maxilla based on cone beam computed tomography (CBCT) data. METHODS: CBCT digital imaging and communications in medicine (DICOM) files of 107 patients (54 with Class I canine relationship and 53 with Class III canine relationship) were collected and the alveolar bone thickness at mid-root (mid-root buccal thickness/MBT; palatal/MPT), apical regions (apical buccal thickness/ABT; palatal/APT) and sagittal angulation (SA) of the maxillary central incisor at the examined side were measured on the mid-sagittal observation plane. Descriptive statistical analysis and frequency distributions of the measurements based on Class I or Class III canine relationship were established. Statistical analyses were performed using Fisher's exact test, independent samples t test and Pearson correlation test with the significance level set at p < 0.05. RESULTS: The frequency distributions of maxillary central incisors' MPT, ABT, APT and SA showed significant differences between Class I and Class III canine relationships (p = 0.030, 0.024, 0.000 and 0.000, respectively). MPT (2.48 ± 0.88 mm vs. 3.01 ± 1.04 mm, p = 0.005), APT (6.79 ± 1.65 mm vs. 8.47 ± 1.93 mm, p = 0.000) and SA (12.23 ± 5.62° vs. 16.42 ± 4.49°, p = 0.000) were significantly smaller in patients with Class III canine relationship. Moreover, SA showed a strong positive correlation with APT (R = 0.723, p = 0.000) and a moderate negative correlation with ABT (R = - 0.554, p = 0.000). CONCLUSIONS: In populations with Class III canine relationship, maxillary central incisors were significantly more labially inclined and have a thinner palatal bone plate at the apex compared with Class I relationship. Clinicians should avoid palatal perforation during immediate implantation at sites of originally protrusive maxillary incisors.

Protoplast fusion enhances lignocellulolytic enzyme activities in Trichoderma reesei.

Protoplast fusion was used to obtain a higher production of lignocellulolytic enzymes with protoplast fusion in Trichoderma reesei. The fusant strain T. reesei JL6 was obtained from protoplast fusion from T. reesei strains QM9414, MCG77, and Rut C-30. Filter paper activity of T. reesei JL6 increased by 18% compared with that of Rut C-30. ß-Glucosidase, hemicellulase and pectinase activities of T. reesei JL6 were also higher. The former activity was 0.39 Uml(-1), while those of QM9414, MCG77, and Rut C-30 were 0.13, 0.11, and 0.16 Uml(-1), respectively. Pectinase and hemicellulase activities of JL6 were 5.4 and 15.6 Uml(-1), respectively, which were slightly higher than those of the parents. The effects of corn stover and wheat bran carbon sources on the cellulase production and growth curve of T. reesei JL6 were also investigated.

Tuning the framework topologies of Co(II)-doped Zn(II)-tetrazole-benzoate coordination polymers by ligand modifications: structures and spectral studies.

In our continuing efforts to explore the effects of ligand modifications on the structures and properties of their metal complexes, we studied the in situ [2 + 3] cycloaddition reactions of benzonitrile, o-phthalodinitrile, 3-cyanobenzoic acid, 4-cyanobenzoic acid with NaN(3) in the presence of Zn(II) and/or Co(II) salts under hydrothermal conditions, and obtained four new Co(II)-doped Zn(II)-tetrazole-benzoate coordination polymers with the formula of [Co(x)Zn(1-x)(L(m))(y)](n) [5-phenyl-1H-tetrazole (HL(1)) for 1, 2-(1H-tetrazol-5-yl)benzoic acid (H(2)L(2)) for 2, 3-(1H-tetrazol-5-yl)benzoic acid (H(2)L(3)) for 3, and 4-(1H-tetrazol-5-yl)benzoic acid (H(2)L(4)) for 4]. The structure of 1 shows a classical diamondoid net, while 2 and 3, take 2D layer structure with (4.6(2))(4.6.4.6) topology and 3D SrAl(2) topology, respectively. The structure of 4 exhibits a four-connected 3D network with rare non-diamondoid 6(6) topology. The coordination modes of the center metal and the ligands in the four complexes are almost the same, being tetrahedral or four-connected, but their topologies are quite different. Thus, the four structurally related ligands allow analysis of the effects of the disposition of a second functional carboxylate group on an aromatic ring and the twist angles of the carboxylate and tetrazoyl out of the plane of the aromatic ring on the overall structural topology of their complexes. Interestingly, the Co(II) ions were doped into the Zn(II) complexes, as confirmed by their macroscopical colors, inductively coupled plasma (ICP) analysis and UV-visible spectra. In addition, the photoluminescence of the four complexes in the solid state at room temperature was briefly studied.

Co-Delivery of Gemcitabine and Mcl-1 SiRNA via Cationic Liposome-Based System Enhances the Efficacy of Chemotherapy in Pancreatic Cancer.

Myeloid cell leukemia 1 (Mcl-1) overexpression is found in various human tumors and has emerged as a promising new target for pancreatic cancer treatment. Recent research has found that most pancreatic cancers develop resistance to the current first-line chemotherapeutic drug, gemcitabine (Gem), and high expression of Mcl-1 can reduce the sensitivity of pancreatic cancer cells to Gem chemotherapy. Therefore, novel strategies, such as combination therapy, to overcome resistance of Gem chemotherapy are needed urgently. Here, we employed a lipid-based delivery system (LPs) to codeliver Mcl-1 siRNA and Gem for pancreatic cancer treatment, named LP-Gem-siMcl-1. LP-Gem-siMcl-1 exhibited an increased cellular uptake, enhanced Mcl-1 down-regulation efficacy, and significant cytotoxicity in the human pancreatic carcinoma cell lines PANC-1 and BxPC-3. Furthermore, tumor inhibition in vivo proved that LP-Gem-siMcl-1 has higher anti-tumor efficiency than LP-siMcl-1 plus LP-Gem, indicating the synergistic anti-tumor effects of Gem and siMcl-1. Meanwhile, histological analysis demonstrated that LPs could efficiently co-deliver Gem and Mcl-1 siRNA to cancerous cells and overcome the resistance of Gem. Taken together, our results offer proof that LP-Gem-siMcl-1 is an effective co-delivery system to treat pancreatic cancers and may serve as a valuable tool for developing new strategies for cancer therapy.

Precision combination therapy for triple negative breast cancer via biomimetic polydopamine polymer core-shell nanostructures.

Photothermal-based combination therapy using functional nanomaterials shows great promise in eradication of aggressive tumors and improvement of drug sensitivity. The therapeutic efficacy and adverse effects of drug combinations depend on the precise control of timely tumor-localized drug release. Here a polymer-dopamine nanocomposite is designed for combination therapy, thermo-responsive drug release and prevention of uncontrolled drug leakage. The thermo-sensitive co-polymer poly (2-(2-methoxyethoxy) ethyl methacrylate-co-oligo (ethylene glycol) methacrylate)-co-2-(dimethylamino) ethyl methacrylate-b-poly (D, l-lactide-co-glycolide) is constructed into core-shell structured nanoparticles for co-encapsulation of two cytotoxic drugs and absorption of small interfering RNAs against survivin. The drug-loaded nanoparticles are surface-coated with polydopamine which confers the nanoformulation with photothermal activity and protects drugs from burst release. Under tumor-localized laser irradiation, polydopamine generates sufficient heat, resulting in nanoparticle collapse and instant drug release within the tumor. The combination strategy of photothermal, chemo-, and gene therapy leads to triple-negative breast cancer regression, with a decrease in the chemotherapeutic drug dosage to about 1/20 of conventional dose. This study establishes a powerful nanoplatform for precisely controlled combination therapy, with dramatic improvement of therapeutic efficacy and negligible side effects.

Construction of anticoagulant poly (lactic acid) films via surface covalent graft of heparin-carrying microcapsules.

Heparin has been widely investigated in medicine and biomedical applications as an anticoagulant. This paper described a covalent modification of poly (lactic acid) (PLA) films with heparin-carrying microcapsules. The heparin-carrying microcapsules were achieved by layer-by-layer (LbL) self-assembly technology by which poly (allylamine hydrochloride) (PAH) and heparin were alternately coated on the Ca(2+)-cross-linked alginate hydrogel. The microcapsules were characterized by scanning electron microscopy (SEM), zeta potential analysis and Fourier transform infrared spectroscopy (FTIR), and then grafted to PLA films by -CONH- linkage between surface PLA molecules with residual primary amino groups on the outer PAH layer of microcapsules, in the presence of catalysts of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). SEM and FTIR revealed the formation of -CONH- linkage. In vitro antithrombogenicity by the method of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) tests showed that surface-modified PLA films had superior coagulation properties to original PLA films. It is suggested that the present method would provide a potential effective tool for biomaterial modification.

[Applications of magnetic resonance imaging in diagnosis of the complications after breast augmentation with polyacrylamide hydrogel injection].

OBJECTIVE: To explore the clinical value of magnetic resonance (MR) imaging in the diagnosis of the complications after breast augmentation with polyacrylamide hydrogel injection. METHODS: MRI was performed in 16 patients who had breast augmentation with polyacrylamide hydrogel injection. The results of magnetic resonance imaging were compared with the clinical symptoms. RESULTS: MRI examinations of the 16 patients showed that (1) 4 breasts in 2 patients were comparatively natural; (2) a large lacteal cyst was detected in one patients in lactation; (3) breast asymmetry occurred in 3 patients (6 sides); (4) in 10 patients (20 sides), the injected gel was in irregular form. The results of MRI were in accord with the clinical symptoms. CONCLUSION: MRI is of great diagnostic value for the complications after breast augmentation with polyacrylamide hydrogel injection.