ABSTRACT
Hydrogels are receiving increasing attention in bioapplications. Among hydrogels, calcium alginate (Ca-alginate) hydrogels are widely used for their biocompatibility, low toxicity, low cost, and rapid fabrication by simple mixing of Ca2+ and sodium alginate (Na-alginate). For bioapplications using hydrogels, it is necessary to construct designed hydrogel structures. Although several methods have been proposed for fabricating designed hydrogels, a simple and low-cost method is desirable. Therefore, we developed a new method using sacrificial templates of sugar structures to fabricate three-dimensional (3D) designed Ca-alginate hydrogels. In this method, Na-alginate solution is mixed with molten sugar, and the resulting highly viscous material used to mold 3D sugar structures as sacrificial templates. Since sugar constructs are easily handled compared to hydrogels, sugar templates are useful for preparing 3D constructs. Finally, the sugar and Na-alginate structure is immersed in a CaCl2 solution to simultaneously dissolve the template and form the Ca-alginate hydrogel. The resulting hydrogel takes the shape of the sugar template. By stacking and fusing various sugar structures, such as fibers and blocks, 3D designed Ca-alginate hydrogels can be successfully fabricated. This simple and low-cost method shows excellent potential for application to a variety of bioapplications.
Subject(s)
Alginates/chemistry , Hydrogels/chemistry , Sugars/chemistry , Calcium Chloride/chemistry , Costs and Cost AnalysisABSTRACT
NAD(P)H:quinone oxidoreductase 1 (NQO1) is a key enzyme providing cytoprotection from quinone species. In addition, it is expressed at high levels in many human tumors, such as breast cancer. Therefore, it is considered to be a potential target in cancer treatment. In order to detect intracellular NQO1 activity in MCF-7 aggregates as a cancer model, we present, in this study, a double-mediator system combined with large-scale integration (LSI)-based amperometric devices. This LSI device contained 20 × 20 Pt working electrodes with a 250 µm pitch for electrochemical imaging. In the detection system, menadione (MD) and [Fe(CN)6]3- were used. Since MD can diffuse into cells due to its hydrophobicity, it is reduced into menadiol by intracellular NQO1. The menadiol diffuses out of the cells and reduces [Fe(CN)6]3- of a hydrophilic mediator into [Fe(CN)6]4-. The accumulated [Fe(CN)6]4- outside the cells is electrochemically detected at 0.5 V in the LSI device. Using this strategy, the intracellular NQO1 activity of MCF-7 aggregates was successfully detected. The effect of rotenone, which is an inhibitor for Complex I, on NQO1 activity was also investigated. In addition, NQO1 and respiration activities were simultaneously imaged using the detection system that was further combined with electrochemicolor imaging. Thus, the double-mediator system was proven to be useful for evaluating intracellular redox activity of cell aggregates.
Subject(s)
Electrochemical Techniques/methods , Enzyme Assays/methods , Ferricyanides/chemistry , NAD(P)H Dehydrogenase (Quinone)/analysis , Vitamin K 3/metabolism , Cell Respiration/physiology , Electrochemical Techniques/instrumentation , Electron Transport Complex I/antagonists & inhibitors , Enzyme Assays/instrumentation , Humans , MCF-7 Cells , NAD(P)H Dehydrogenase (Quinone)/metabolism , Optical Imaging/instrumentation , Optical Imaging/methods , Oxidation-Reduction , Rotenone/pharmacology , Vitamin K/analogs & derivatives , Vitamin K/chemistry , Vitamin K 3/chemistryABSTRACT
OBJECTIVE: The non-pregnant uterus shows wave-like activity (uterine peristalsis). This pilot study was intended to determine: (1) whether uterine peristalsis during the menstrual cycle is detectable by cine magnetic resonance imaging (MRI); (2) the effects of leiomyoma on uterine peristalsis. STUDY DESIGN: Mid-sagittal MRI was performed sequentially with T2-weighted single-shot fast spin-echo (SSFSE) in 3 normal ovulatory volunteers and 19 premenopausal women with uterine leiomyoma. Direction and frequency of movement of the junctional zone were evaluated using a cine mode display. RESULTS: Junctional zone movement was identified in all subjects. Direction of uterine peristalsis in normal volunteers was fundus-to-cervix during menstruation, cervix-to-fundus during the periovulatory phase, and isthmical during the mid- and late-luteal phases. Abnormal peristaltic patterns were detected in three of five patients with uterine leiomyoma during menstruation and in the mid-luteal phase of the cycle, respectively. CONCLUSION: Cine MRI is a novel method for evaluation of uterine peristalsis. Results of this pilot study suggest that abnormal uterine peristalsis during menstruation and the mid-luteal phase might be one of the causes of hypermenorrhea and infertility associated with uterine leiomyoma.
