Advances in the design of macroporous polymer scaffolds for potential applications in dentistry

A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications

Visual analytics and information retrieval

Visual Analytics (VA) [1] is an emerging multi-disciplinary area that takes into account both ad-hoc and classical Data Mining (DM) algorithms and Information Visualization IV (IV) techniques, combining the strengths of human and electronic data processing. Visualisation becomes the medium of a semi-automated analytical process, where human beings and machines cooperate using their respective distinct capabilities for the most effective results. Decisions on which direction analysis should take in order to accomplish a certain task are left to the user. Although IV techniques have been extensively explored [2], combining them with automated data analysis for specific application domains is still a challenging activity [3]. This chapter provides an introduction of the main concepts behind VA and presents some practical examples on how apply it to Information Retrieval (IR)

Complement Resistance Is Essential for Colonization of the Digestive Tract of Hirudo medicinalis by Aeromonas Strains

From the crop of the medicinal leech, Hirudo medicinalis, only Aeromonas veronii bv. sobria can be cultured consistently. Serum-sensitive A. veronii mutants were unable to colonize H. medicinalis, indicating the importance of the mammalian complement system for this unusual simplicity. Complementation of one selected mutant restored its ability to colonize. Serum-sensitive mutants are the first mutant class with a colonization defect for this symbiosis

Separation of antibiotic-treated mycobacterial subpopulations using multiple-frequency dielectrophoresis

Exposure of a bacterial culture to an antibiotic or other lethal stress typically results in the generation of sub-populations of live cells ("persisters") and dead cells, and, in some cases, viable but non-culturable cells. Studies aimed at understanding the mechanisms of antibiotic killing and bacterial persistence will require the purification and analysis of each of these sub-populations in isolation. This paper reports a method based on continuous-flow dielectrophoresis to separate live and dead cells from antibiotic-treated bacterial cultures. Our experiments were carried out on Mycobacterium smegmatis, a model organism that is closely related to the etiological agent of human tuberculosis

Device for application of medium to human tissue or animal body such as eye, has carrier which is provided with micro-cavity for containing medium in direct contact with object on which medium is to be applied

NOVELTY - The device has a carrier (1) which is provided with micro-cavity (2) for containing medium in direct contact with the object on which the medium is to be applied. Other carrier is provided with ring to protect the medium from environment when the carrier is applied to patient. The sensor is provided with polymer or hydrogel pouch. The sensor is formed as carbon dioxide or metabolite concentration sensor. USE - Device for application of medium to human tissue or animal body such as eye, gingiva, skin, wound or internal organ (all claimed). Can also be used in scalp and mucuous membrane. ADVANTAGE - The carrier is provided with micro-cavity for containing medium in direct contact with the object on which the medium is to be applied. The carrier can be used in simple and precise way to treat the patient. The modified cells or non-epithelial cells to the ocular surface can be transplanted. Transplantation of cells in suspension to other superficial tissues such as gums, mucuous membranes, skin for hair follicle regeneration can be obtained. The dosable application of substances with or to the grafted cells can be obtained to improve engraftment, proliferation and differenciation of cells allowing the use of cells in suspension. The cell culture on lens or another media can be avoided so as to make transplanting easier and faster. The control of the location and of the quantity of cells applied to the target tissue can be allowed

A miniaturized continuous dielectrophoretic cell sorter and its applications

There is great interest in highly sensitive separation methods capable of quickly isolating a particular cell type within a single manipulation step prior to their analysis. We present a cell sorting device based on the opposition of dielectrophoretic forces that discriminates between cell types according to their dielectric properties, such as the membrane permittivity and the cytoplasm conductivity. The forces are generated by an array of electrodes located in both sidewalls of a main flow channel. Cells with different dielectric responses perceive different force magnitudes and are, therefore, continuously focused to different equilibrium positions in the flow channel, thus avoiding the need of a specific cell labeling as discriminating factor. We relate the cells’ dielectric response to their output position in the downstream channel. Using this microfluidic platform that integrates a method of continuous-flow cell separation based on multiple frequency dielectrophoresis, we succeeded in sorting viable from nonviable yeast with nearly 100% purity. The method also allowed to increase the infection rate of a cell culture up to 50% of parasitemia percentage, which facilitates the study of the parasite cycle. Finally, we prove the versatility of our device by synchronizing a yeast cell culture at a particular phase of the cell cycle avoiding the use of metabolic agents interfering with the cells’ physiology

Dielectrophoretic sorting on a microfabricated flow cytometer: Label free separation of Babesia bovis infected erythrocytes

Dielectrophoresis is a method that has demonstrated great potential in cell discrimination and isolation. In this study, the dielectrophoretic sorting of normal and Babesia bovis infected erythrocytes was performed using a microfabricated flow cytometer. Separation was possible through exploitation of the dielectric differences between normal and infected erythrocytes, essentially due to the higher ionic membrane permeability of B. bovis infected cells. Sorting experiments were performed inside a microchip made from Pt microelectrodes and SU-8 channels patterned on a glass substrate. Optimum cell separation was achieved at 4 MHz using an in vitro culture of B. bovis suspended in 63 mS/m phosphate buffer and applying a sinusoidal voltage of 15 V peak-to-peak. Normal erythrocytes experienced stronger positive dielectrophoresis (pDEP) than B. bovis infected cells, moving them closer to the microelectrodes. Under these conditions it was possible to enrich the fraction of infected cells from 7 to 50% without the need of extensive sample preparation or labelling. Throughout the experiments very few microliters of sample were used, suggesting that this system may be considered suitable for integration in a low-cost automated device to be used in the in situ diagnostic of babesiosis