Relative Cell Proliferation Rate Research Articles

Improvement of Cu and Zr doped Diamond-like carbon coatings on comprehensive performance of Ni-Ti alloy potentially used in braided vascular stent

Wear and corrosion between braided wires will not only release toxic nickel ions, but also cause fatigue fracture of Ni-Ti alloy-based braided stents. In this study, Cu and Zr doped Diamond-like carbon (DLC) film containing Cr intermediate layer and Cr:C gradient layer were prepared with the total thickness of about 2.17 μm and 2.05 μm, respectively. In order to study the improvement of DLC coating on the comprehensive properties of Ni-Ti based stent, the nano-mechanical, tribological, electrochemical corrosion, nickel ion release and cytotoxicity properties were all evaluated. The results showed that the nano hardness and elastic modulus for Zr-DLC film were 12.32 GPa and 138.49 GPa, respectively increased by 192% and 102% compared with bare NiTi. Cu-DLC and Zr-DLC coatings can not only significantly reduce the friction coefficient, but also greatly reduce the wear rate such as by three orders of magnitude in dry sliding condition compared with bare NiTi. Zr-DLC film reduced the icorr value with a reduction amount of 96.1%, with the values of 8.41 × 10−8 and 3.26 × 10−9 A/cm2 for NiTi and Zr-DLC, respectively. After 28 days of soak experiment in phosphate buffer solution, the total nickel ion release amount was only 5.6 ng/L for Cu-DLC and 6.9 ng/L for Zr-DLC, which was reduced by 96.1% and 95.2%, respectively. The relative cell proliferation rate results showed that NiTi and Zr-DLC were both Grade 0, which indicated good cytotoxicity result. However, the cytotoxicity of Cu-DLC reached grade 2 (the relative cell proliferation rate was 71.73%). Based on the above results, Zr-DLC showed good comprehensive performances and was expected to be used as a protective layer on the surface.

Improvement of TiN coating on comprehensive performance of NiTi alloy braided vascular stent

In order to improve the wear and corrosion resistance of Ni–Ti alloy-based braided stent, High-temperature nitriding technology was used to prepare the TiN coating with different process parameters. Based on the systematic evaluation of nano-mechanical properties, tribological properties, electrochemical corrosion properties, nickel ion release properties and cytotoxicity, the feasibility of the application of the TiN coating in braided peripheral vascular stents was explored. The results showed that TiN coating included the TiN layer of about 1μm and nitrided layer of 50μm under the process parameters of 800 °C and 1h. The nano hardness and elastic modulus for TiN film were 20.50GPa and 281.66GPa, respectively. TiN coating can not only significantly reduce the friction coefficient in dry sliding and lubrication state, but also greatly reduce the wear rate such as by three orders of magnitude in dry sliding condition. TiN film reduced the icorr value with a reduction amount of 75.1%, with the value of 8.41 × 10−8 and 2.09×10−8A/cm2 for NiTi and TiN, respectively. After 28 days of soak experiment in phosphate buffer solution, the total nickel ion release amount of sample TiN#4 and bare NiTi were 0.094 and 1.452ng/m, which was reduced by 93.5%. The relative cell proliferation rate results showed that TiN samples all exceeded 90%, which mean that the cytotoxicity grade was 0. Based on the above results, TiN showed good nano-mechanical, tribological, electrochemical corrosion, nickel ion release and cytotoxity properties, and was expected to be used as a protective layer on the surface of Ni–Ti alloy stent.

Study on the preparation and properties of acellular matrix from the skin of silver carp (Hypophthalmichthys molitrix).

Acellular matrices are mainly composed of mammalian tissues, and aquatic tissues with lower biological risks and less religious restrictions are considered alternatives to mammalian tissues. The acellular fish skin matrix (AFSM) has been commercially available. Silver carp has the advantages of farmability, high yield and low price, but there are few studies on the silver carp acellular fish skin matrix (SC-AFSM). In this study, an acellular matrix with low DNA and endotoxin was prepared from the skin of silver carp. After treatment with trypsin/sodium dodecyl sulfate and Triton X-100 solutions, the DNA content in SC-AFSM reached 11.03 ± 0.85 ng/mg, and the endotoxin removal rate was 96.8%. The porosity of SC-AFSM was 79.64% ± 0.17%, which is favorable for cell infiltration and proliferation. The relative cell proliferation rate of SC-AFSM extract was 117.79% ± 15.26%. The wound healing experiment showed that SC-AFSM had no adverse acute pro-inflammatory response, which had a similar effect as commercial products in promoting tissue repair. Therefore, SC-AFSM has great application potential in biomaterials.

In vitro physicochemical and biological properties of titanium alloy, zirconia, polyetheretherketone, and carbon fiber-reinforced polyetheretherketone

Implant repair is a common means to restore the normal function of the hard tissues (bone or teeth). At present, the commonly and potentially used implant materials include titanium alloy (Ti), zirconia (Zr), polyetheretherketone (PEEK), and 30% carbon fiber reinforced PEEK (CFR-PEEK). This study compares their physicochemical and biological properties, including surface morphology, contact angle, nano hardness, elastic modulus, and the impact on the proliferation and osteogenic differentiation of bone marrow mesenchyml stem cell. Additionally, the differences in bacteria adhesion rates among materials were compared. CFR-PEEK had the highest contact angle, followed by PEEK, Zr, and Ti. Zr had the highest nano hardness and modulus of elasticity, followed by Ti, CRF-PEEK, and PEEK. There was no statistically significant difference in cytotoxicity among materials based on the liquid extract test. However, the relative cell proliferation rate on the surface of CFR-PEEK was slightly lower than that of Ti and Zr. Moreover, alkaline phosphatase activity, extracellular matrix mineralization, and osteogenic gene expression with the Ti and Zr materials were higher than with the PEEK and CFR-PEEK materials at Day 7, and Zr showed the highest osteogenic gene expression level among materials at Day 14. Ti had the greatest number of bacterial colonies that adhered to it, followed by Zr, CFR-PEEK, and PEEK. While the mechanical properties of PEEK and CFR-PEEK were closer to bone tissue and their anti-adhesion effect against bacteria was better than those of Ti and Zr, modification methods are needed to improve the osteogenic properties of these biopolymers.

Chitosan Nanoparticles Loaded with TGF-β1 Inhibit Cervical Cancer Cell Progression Through Down-Regulation of MicroRNA-155 and Activation of Tim-3 Pathway.

Chemically modified chitosan nanoparticles (NPs) are capable of releasing their own substances to target cells or tissues, improving microenvironment and promoting wound healing. This study aimed to explore the molecular mechanism underlying chitosan NPs loaded with TGF-β1 participating in cervical cancer (CC) progression. TGF-β1-loaded-chitosan NPs were prepared and particle size distribution, zeta potential and encapsulation efficiency of NPs were determined. MTT assay assessed the toxicity of NPs to macrophages. CC cells were co-cultured with TGF-β1-loaded chitosan NPs (experimental group) or pure chitosan NPs (control group) and cells were cultured alone to produce control group. After treatment, flow cytometry was conducted to detect apoptosis and cycle. Cancer cell migration was evaluated by Transwell assay, and miR-155 and Tim-3 expression was determined. At a ratio of 2:1 chitosan and TGF-β1, the particle size was102.65±11.98 nm, which was smallest, with high encapsulation rate of 81.26%, and low potential of 1.46±1.71. NP toxicity increased as concentration rose and relative cell proliferation rate was >80%, indicated as non-toxic. CC tissues had positive expression of CD163 and TGF-β1 (95%) (p < 0.05). Treatment with TGF-β1-loaded chitosan NPs induced increased apoptosis rate of 9.13±2.15%, reduced migration (67.65±9.91) and invaded cells (19.98±3.41), causing cell accumulation in the S phase when compared to the blank and control groups (p < 0.05). Besides, experimental group exhibited lower expression of miR-155 (0.39±0.59) and higher expression of Tim-3 (2.87± 0.51), which was higher than the blank group and control group. The optimal concentration ratio for producing TGF-β1-loaded chitosan NPs was 2:1, with less toxicity. The composite NPs suppressed malignant characteristics of CC cells through down-regulation of miR-155 and activation of Tim-3 signal pathway on the surface of macrophages, promoting secretion of macrophage inflammatory factors.

Cytotoxicity of Ti–6Al–4V–5Cu Alloy to MC3T3-E1 Cells

The aim of this work was to study the cytotoxicity of Ti–6Al–4V–5Cu (TC4–Cu) alloy for dental applications and evaluate the cell viability of different fabricated TC4–Cu alloys in contact with MC3T3-E1 cells in vitro. Ti–6Al–4V (TC4) alloy was used as a negative control to evaluate the cytotoxicity level of TC4–Cu alloy so as to provide basic support for the dental clinical application. Control group TC4 and experimental group TC4–Cu with different fabrications were incubated in the cell culture medium. The absorbance value of mouse osteoblast MC3T3-E1 cells was detected by CCK-8 assay after 1, 3 and 7 days, respectively. The relative proliferation rate of cells was calculated, and then the toxicity level was valued for each group. Cell morphology on the surface was also studied by observing the cytoskeleton through F-actin filament staining. The experimental results showed that the absorbance values for the experimental and the negative control groups were not same at different time points. Compared with different fabricated TC4–Cu alloys, the annealing-TC4–Cu alloy showed much better biocompatibility. The mouse osteoblast MC3T3-E1 cells cultured with annealing-TC4–Cu, rolling-TC4–Cu and solution + aging-TC4–Cu have no toxic effects, and these alloys could promote the proliferation of mouse osteoblasts.

The Calcium Channel Affect Osteogenic Differentiation of Mesenchymal Stem Cells on Strontium-Substituted Calcium Silicate/Poly-ε-Caprolactone Scaffold

There had been a paradigm shift in tissue engineering studies over the past decades. Of which, part of the hype in such studies was based on exploring for novel biomaterials to enhance regeneration. Strontium ions have been reported by others to have a unique effect on osteogenesis. Both in vitro and in vivo studies had demonstrated that strontium ions were able to promote osteoblast growth, and yet at the same time, inhibit the formation of osteoclasts. Strontium is thus considered an important biomaterial in the field of bone tissue engineering. In this study, we developed a Strontium-calcium silicate scaffold using 3D printing technology and evaluated for its cellular proliferation capabilities by assessing for protein quantification and mineralization of Wharton’s Jelly mesenchymal stem cells. In addition, verapamil (an L-type of calcium channel blocker, CCB) was used to determine the mechanism of action of strontium ions. The results found that the relative cell proliferation rate on the scaffold was increased between 20% to 60% within 7 days of culture, while the CCB group only had up to approximately 10% proliferation as compared with the control specimen. Besides, the CCB group had downregulation and down expressions of all downstream cell signaling proteins (ERK and P38) and osteogenic-related protein (Col I, OPN, and OC). Furthermore, CCB was found to have 3–4 times lesser calcium deposition and quantification after 7 and 14 days of culture. These results effectively show that the 3D printed strontium-contained scaffold could effectively stimulate stem cells to undergo bone differentiation via activation of L-type calcium channels. Such results showed that strontium-calcium silicate scaffolds have high development potential for bone tissue engineering.

GATA-3 Stimulates Proliferation of Endometriotic Cells.

This study aimed to investigate whether there was a correlation between the expression of GATA binding protein 3 (GATA-3) and the proliferation of endometrium cells from women with endometriosis. Endometrial tissue was collected from 20 women with endometriosis (experimental group) and 10 women without endometriosis (control group). The primary endometrial cells were then cultured and identified. Each group of cells were further divided into four groups. The control group was divided into control-no treatment (C-N), control-negative control (C-NC, transfected with a scrambled siRNA negative control), control-lentiviral transfection control (C-LC) and control-GATA-3 lentiviral transfection (C-G3); the experimental group was divided into experiment-no treatment (E-N), experiment-negative control (E-NC), experiment-lentiviral transfection control (E-LC) and experiment-siGATA-3 lentiviral transfection (E-siG3). RT-PCR and western blot were used respectively to detect the endometrium cells' GATA-3 mRNA and protein expression. Further, Cell Counting Kit-8 was used to measure the endometrium cells' proliferation. The relative expression of GATA-3 mRNA and protein in the E-N group was significantly higher than in the D-N group and E-siG3 group (P < 0.05). The relative cell proliferation rate in the C-G3 group at 48 h, 72 h and 96 h was significantly higher than in the C-N, C-NC and C-LC groups (P < 0.05), while in the experimental group, the proliferation rate of the E-siG3 group was significantly lower than in the E-N, E-NC and E-LC groups (P < 0.05). This study suggests the role of GATA-3 in promoting proliferation of endometrial cells; therefore, GATA-3 may play an essential role in the development of endometriosis.

Measures for Maintaining the Vitality of Peripheral Blood Hematopoietic Stem Cells in vitro

To explore the maintaining measures for the vitality of hematopoietic stem cells (HSC) in vitro, so as provide technical support for ultra long distance transport of HSC collected from unrelated donors. Peripheral blood hematopoietic stem cells (PBHSC) were treated by different methods according to various groups, then stored at 4 ℃ in the refrigerator. The percentage of CD34+ cells, relative cell activity, relative cell proliferation rate, relative colony-forming rate, oxygen fraction and intracellular reactive oxygen species (ROS) were detected at 0, 24, 48 and 72 h after storage of PBHSC respectively. The percentage of CD34+ cells during 72 h storage did not altered. Along with the prolonging of storage time, the relative cell activity, relative cell proliferation rate and relative colony-forming rate gradually decreased in untreated PBHSC(control group), the related coefficients were -0.796, -0.883 and -0.815 respectively. Plasma dilution, antioxidants and oxygenation could improve the relative cell activity and relative cell proliferation rate, but oxygenation could decrease the relative colony-forming rate of PBHSC. The combination of 2 or 3 factors showed stronger protection effects on PBHSC. The intracellular level of ROS decreased gradually with the prolonging of storage time. Oxygenation of PBHSC could increase oxygen fraction, and also increase the intracellular level of ROS at the same time. The addition of antioxidants could reduce the level of ROS. The percentage of CD34+ cells can not serve as the indicator of PBHSC vitality. Plasma dilution, oxygenation and antioxidants can increase the survival and viability of PBHSC, but oxygenation can increase the intracellular ROS level and impair colony-forming ability of PBHSC. The combination of multiple factors can maintain the vitality of PBHSC better.

Magnesium Phosphate/Polybutylene Succinate Composite for Bone Repair

MP/PBS composite was fabricated by melt blending method. The weight loss ratio of MP/PBS composite reached 35.43 wt.% after immersion into phosphate buffered saline solution for 12 weeks, and the pH change from 7.40 to 7.72. The relative proliferation rate of cells on the materials increased with time and the proliferation of the cells on the MP/PBS composite was significantly higher than PBS. The results reveal MP/PBS composite has good biocompatibility, which satisfied the relevant criterion on biomaterials.

Evaluation of the Biocompatibility of a Ti-Ta-Sn Alloy Using Cell Cultures

The purpose of this study was to determine the suitability of a newly developed Ti-Ta-Sn alloy for use as a metallic biomaterial. The in vitro cell toxicity was determined by testing the corroding metal solutions using cell culture. Besides the cell adhesion rate, cell proliferation and colony formation were tested on the metal plates. Results of the cytotoxicity tests for higher concentrations of the corroding metal solutions (32 ppm and 64 ppm) revealed that the toxicity for U937 macrophages was lowest for the Ti-Ta-Sn alloy, followed by SUS316L and Co-Cr-Mo, with Ni-Ti being the most toxic. The Ti-Ta-Sn solution showed no cytotoxicity, even at a concentration of 64 ppm. The Co-Cr-Mo and Ni-Ti solutions showed high cytotoxicity for L929 cells. The cytotoxicity that was measured from the lactate dehydrogenase (LDH) release was highest for the Co-Cr-Mo alloy, followed by Ni-Ti, SUS316L, and Ti-Ta-Sn that showed the lowest value. Besides, the success rate of cell adhesion was highest for the Ti-Ta-Sn alloy after culturing for 6, 12, and 24 h. The cell proliferation tests showed that the cell proliferation speed and the relative cell proliferation rate after 3 days were both highest on Ti-Ta-Sn plates. Colony formation was highest on the Ti-Ta-Sn plates, and it was lowest on Co-Cr-Mo and SUS316L plates. These results demonstrated the suitability of the Ti-Ta-Sn alloy for use as a metallic biomaterial at the cellular level.

The effect of grain size on the biocompatibility, cell–materials interface, and mechanical properties of microwave‐sintered bioceramics

The effect of decreasing the grain size on the biocompatibility, cell-material interface, and mechanical properties of microwave-sintered monophase hydroxyapatite bioceramics was investigated in this study. A nanosized stoichiometric hydroxyapatite powder was isostatically pressed at high pressure and sintered in a microwave furnace in order to obtain fine grained dense bioceramics. The samples sintered at 1200°C, with a density near the theoretical one, were composed of micron-sized grains, while the grain size decreased to 130 nm on decreasing the sintering temperature to 900°C. This decrease in the grain size certainly led to increases in the fracture toughness by much as 54%. An in vitro investigation of biocompatibility with L929 and human MRC-5 fibroblast cells showed noncytotoxic effects for both types of bioceramics, while the relative cell proliferation rate, cell attachment and metabolic activity of the fibroblasts were improved with decreasing of grain size. An initial in vivo investigation of biocompatibility by the primary cutaneous irritation test showed that both materials exhibited no irritation properties.

Studies on constituents of cultures of fungus Phellinus igniarius

To investigate the chemical constituents of the culture of Phellinus igniarius and their phamacological activities. The constituents were isolated by using a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC. Structures of the isolates were identified by spectroscopic data analysis. Cytotoxic, neuroprotective, hepatoprotective, anti-inflammatory, and anti-HIV activities were screened by using cell-based models. Twenty-nine constituents were isolated. Their structures were identified as three sesquiterpenes: 3S,9R,10S-3-hydroxy-11, 12-O-isopropyldrimene(1), 3S, 9R, 10S-3, 11, 12-trihydroxydrimene (2), and 3S, 4S, 9R, 10S-11, 12, 14-trihydroxydrimene(3); three steriods: 24R-ergosta-4, 6, 8(14), 22-tetraen-3-one (4), stigmasta-7, 22-diene-3b, 5a, 6a-triol (5), and 5a, 8a-epi dioxyergosta-6, 22-diene-3b-ol (6); fourteen cyclo-dipeptide: cyclo (L-Pro-L-Val) (7), cycle (L-Leu-D-Pro) (8), cyclo (L-Leu-L-Pro) (9), cyclo (ILe-Pro) (10), cyclo (Gly-Leu) (11), cyclo (Phe-Ser) (12), cyclo (Ala-Pro) (13), cyclo (Ala-Phe) (14), cyclo (4-HyP-Phe) (15) , cyclo (L-Phe-D-Pro) (16), cyclo (D-Phe-D-Pro) (17), cyclo (6-HyP-Phe) (18), cycle (Gln-Pro) (19), and cycle (Asn-Leu) (20); and nine other compounds: N-acetyl-phenylalanine (21), adenosine (22), phenyldiethanol (23), o-hydroxy-phenylethanol (24), benzoic acid (25), p-methoxybenzoic acid (26), m-methoxybenzoic acid (27), hexadecanoic acid (28), and 3-pyridinecarboxylic acid (29). In the in vitro assays, at a concentration of 1 x 10(-5) mol x L(-1), compounds 5 and 8 showed neuroprotective activity against MPP+ induced PC12-syn cell damage, with a relative cell proliferation rate of 90.3% and 87.5% (P < 0.05). At 1 x 10(-5) mol x L(-1), compounds 12 and 18 showed hepatoprotective activities against DL-galactosamine-induced toxicity examined in WB-F344 cell, with cell survival rates of 25% and 24%, respectivily. Compounds 1-29 were obtained from P. igniarius for the first time. Compounds 5 and 8 showed potent PC12-syn protective activities, while 12 and 18 showed hepato cytes (WB-F344 cells) protective activities.

Terpenoids of Heteroplexis micocephala and their bioactivities

To investigate the chemical constituents of Heteroplexis nicocephala. The constituents were isolated by using a combination of various chromatographic techniques including column chromatography over silica gel, Pharmadex LH-20, and C-18, as well as reversed-phase HPLC. Structures of the isolates were identified by spectroscopic data analysis. In vitro cytotoxic, neuroprotective, and anti-inflammatory activities were screened by using cell-based models. Seventeen terpenoids were isolated. The structures were identified as two monoterpenoids: (-)-bomyl ferulate(1) and loliolide(2). Seven sesquiterpenoids: 1beta-hydroxy-alpha-cyperone(3) , alpha-rotunol(4), 10alpha-hydroxycadin-4-en-15-al (5), 1-epi-10beta-hydroxycadin-4-en-15-al(6), 10alpha-hydroxyisodauc-3-en-15-al(7), germacrene B(8), and mandassidione(9). Five diterpenoids: 12-epi-bacchotricuneatin A(10), 1-hydroxy-12-epi-bacchotricuneatin A(11), cleroinermin(12), desoxyarticulin(13), and anhydroolearin(14). And three triterpenoids: friedelin (15), ursolic acid(16), and obtusalin(17). In the in vitro assays, 1 showed selective cytotoxic activity against BGC-823, with an IC50 value of 8.00 x 10(-5) mol x L(-1). At a concentration of 1 x 10(-5) mol x L(-1), 12 showed neuroprotective activity against MPP+ induced PC12-syn cell damage, with a relative cell proliferation rate of 104.32% (P < 0.001). 2 exhibited inhibitory activity against the release of beta-glucuronidase from the polymorphous nuclear leukocytes induced by PAF, with an inhibitory rate of 52.7% (P < 0.05) at the same concentration. Compounds 1-17 were obtained from the genus Heteroplexis for the first time. 1 showed selective cytotoxic activity against human gastric cancer cell lines (BGC-823), 12 and 2 showed potent neuroprotective and anti-inflammatory activities, respectively.

The Properties of Nanohydroxyapatite Materials and its Biological Effects

The nanohydroxyapatites (HAP) and its biological effects have been studied using ultraviolet absorption spectrum, X-ray diffraction (XRD) structure analysis, fluorescent and infrared spectrum of absorption and MTT method. The nanohyd- roxyapatites are prepared and made by using Sol-gel method, in which the parameters of process and reaction are controlled as: PH > 9, Ca/P = 1.67, sintering temperature of 1100?C and sintering time 2 hours. The results of the study show that nanohydroxyapatites can absorb the amino acid molecules, the absorption is better for stronger acidity of amino acids. We also find that the nanohydroxyapatites and complex of nanoHAP+ nanoCrO2 can all restrain the proliferation of cells, but their toxiciteis are all first degree or minor, but the restrained effect of the latter is smaller than that of the former, although they can decrease the relative proliferation rate of cells. The nanohydroxyapatites can also change the molecular structure of human serum albumin.