Entrapped Cells Research Articles

Immobilization of diesel-degrading consortia for bioremediation of diesel-contaminated groundwater and seawater

This study investigated the potential application of immobilized diesel-degrading consortia for diesel removal in aqueous environments. The microorganisms were entrapped using polyurethane-polyurea co-polymers, alginate, and activate carbon, and total petroleum hydrocarbon (TPH) degradability were evaluated under freshwater and seawater conditions with diesel oil. The results indicated that immobilized cells remained active after entrapment, but rapid diesel degradation occurred after sufficient suspended cells growth in aqueous medium, suggesting that entrapped cells continuously released freely suspended cells and suspended cells degraded diesel as well. Under phosphorous-sufficient conditions (P/TPH>35%), TPH degradation efficiency was achieved at 80% even at low nitrogen condition (N/TPH<10%). Under phosphorous-insufficient conditions (P/TPH<10%), the better degradation efficiency was obtained only at high nitrogen content (TPH:N > 100:7). The stoichiometric relationship for diesel degradation, nitrogen consumption, phosphorous consumption, biomass production was obtained (100:5:0.9:35). The results of repeated batch indicated that immobilized cells could be repeatedly used for diesel degradation in simulated groundwater and seawater environments for more than 360 days of operation. With a combination of copolymer, alginate, and activate carbon, the entrapped matrix presented advantages on high surface area, high porosity, and high mechanical strength for a long-term operation for diesel bioremediation in aqueous environments.

Removal of ammonium and nitrate in recirculating aquaculture systems by the epiphyte Stigeoclonium nanum immobilized in alginate beads

Incorporation of microalgae in recirculating aquaculture systems (RAS) would absorb the inorganic nitrogen and phosphorus, thus potentially contributing to water purification. Immobilization or entrapment of microalgal cells in spherical gels is a potential method to incorporate microalgae in the RAS. Filamentous microalgae are presumed to suit the immobilization technique because the gels can serve as substrates for the microalgae to attach. In the first experiment of this study, growth and nitrogen uptake of Stigeoclonium nanum, a filamentous microalga, was compared when cultured using an immobilization technique or in a normal suspension. In the second experiment, immobilized S. nanum was cultured in 4 media with different total ammonia nitrogen (TAN) and nitrate-nitrogen (NO3-N) concentrations. The results showed a significantly higher algal growth and TAN removal by S. nanum immobilized in alginate than for S. nanum in free suspension culture. When both TAN and NO3-N were added to the culture medium, the uptake of TAN by immobilized S. nanum was significantly more efficient than NO3-N uptake. Our results indicated that S. nanum was able to grow immobilized in a medium, exhibiting a higher growth and TAN uptake than when the algae were in free suspension. S. nanum preferred ammonium over nitrate, which is suitable for RAS that require removal of the total ammonia which is produced by fish and by organic decomposition in the system.

Collagenous scaffolds supplemented with hyaluronic acid and chondroitin sulfate used for wound fibroblast and embryonic nerve cell culture.

Tissue engineering is a strategy aimed at improving the regeneration of injured tissues. The aim of the present study was to determine whether a tri-copolymer composed of crosslinked collagen, chondroitin sulfate and hyaluronic acid (Col + CS + HA) provides a better environment for fibroblast and embryonic nerve cell culture than a collagenous scaffold (Col). The porosity of each of the matrices was characterized with a scanning electron microscope. Fibroblasts were isolated from rat wound granulation tissue (polypropylene net implanted subcutaneously). Embryonic nerve cells were obtained from the brains of rat embryos. The cells were applied to scaffolds and then stained with bisbenzimide to calculate cell entrapment within the material. The metabolic activity of the cells cultured within the scaffolds was tested using the 3-(4,5-dimethythiazol2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The Col scaffolds had a homogenously porous structure with a pore diameter of 50 μm for 70% of pores. The pore diameter in the tri-copolymer (Col + HA + CS) ranged from 24 to 160 μm (95% of total pore volume). Four times more cells (fibroblasts and embryonic nerve cells) were trapped within the superficial part of the collagenous scaffold than that of the tri-copolymer. On the third day of culture the metabolic activity of the fibroblasts within the 2 tested scaffolds was significantly higher than in the control conditions (cell culture on a laminin-coated surface). Also, the embryonic nerve cells demonstrated increased metabolic activity in Col + CS + HA scaffolds than the Col scaffolds. Both fibroblasts and embryonic nerve cells could be seeded within the 2 tested scaffolds. Both the scaffolds provide good conditions for fibroblast culture. However, the Col + CS + HA tri-copolymer is preferable for embryonic nerve cell engineering.

Effect of encapsulant and cryoprotectant on the viability of probiotic Pediococcus acidilactici ATCC 8042 during freeze-drying and exposure to high acidity, bile salts and heat

Encapsulation and freeze drying are among the most preferable preservation methods due to their considerable effects on probiotics survival. The effects of different cryoprotectants on the viability of free cells during freeze drying and coating materials for encapsulation strategy have been investigated by various researchers. However, information on the effect of cryoprotectants on the viability of the encapsulated probiotics during freeze-drying seems scarce. In this study Pediococcus acidilactici ATCC 8042 was encapsulated using calcium-alginate (ALGsm-FD) and calcium-alginate co-coating with chitosan (CHsm-FD) via extrusion technique. They were subsequently freeze dried using 10% (w/w) skim milk as cryoprotectant. Immediately after the freeze drying, ALGsm-FD showed the highest survival (15.77%) compared to the CHsm-FD (0.36%), free cells protected with skim milk (FCsm-FD) (11.02%) and both encapsulated and free cell samples without the addition of skim milk (0%). Co-coating the entrapped cells in alginate bead with chitosan was only accommodating the cells survival during bile solution (pH = 8.25) treatment but not for freeze drying and gastric juice treatment (pH = 1.55). In comparison, ALGsm-FD and CHsm-FD were found to be more heat tolerance than FCsm-FD. The findings indicated that the supplementation of cryoprotectant conferred an important protective effect to either encapsulated or free probiotic cells during freeze drying.

Comparison of various types of collagenous scaffolds applied for embryonic nerve cell culture

The purpose of the study was to confirm whether collagen-based scaffolds using different cross-linking methods are suitable elaborate environments for embryonic nerve cell culture. Three 3D sponge-shaped porous scaffolds were composed using collagen alone, collagen with chondroitin sulphate modified by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride, and collagen cross-linked by 2,3-dialdehyde cellulose (DAC).Embryonic nerve cells from rats were applied to the scaffolds and stained with bisbenzimide to study cell entrapment within the scaffolds. The metabolic activity of the cells cultured in the scaffolds was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.The majority of cells were differentiated into neurocytes or oligodendrocytes. Collagen and collagen-chondroitin sulphate scaffolds entrapped a low number of cells. The highest cell density was found in the collagen-DAC scaffold. Moreover, in collagen-DAC scaffolds, the metabolic activity was markedly higher than in the other samples.Although all used scaffolds are suitable for the culture of embryonic nerve cells, the collagen-DAC scaffold properties are the most favorable. This scaffold entraps the highest number of cells and constitutes a favorable environment for their culture. Hence, the Col-DAC scaffold is recommended as an effective carrier for embryonic nerve cells.

Two schemes for production of biosurfactant from Pseudomonas aeruginosa MR01: Applying residues from soybean oil industry and silica sol–gel immobilized cells

Rhamnolipids are the most common biosurfactants and P. aeruginosa strains are the most frequently studied microorganisms for the production of rhamnolipids. Eco-friendly advantages and promising applications of rhamnolipids in various industries are the major reasons for pursuing the economic production of these biosurfactants. This study shows that cultivation of P. aeruginosa MR01 in medium contained inexpensive soybean oil refinery wastes which exhibited similar levels and homologues of rhamnolipids. Mass spectrometry indicated that the Rha-C10-C10 and Rha-Rha-C10-C10 constitute the main rhamnolipids in different cultures of MR01 including one of oil carbon source analogues. Moreover, rhamnolipid mixtures extracted from different cultures showed critical micelle concentrations (CMC) in the range of ≃24 to ≃36mg/l with capability to reduce the surface tension of aqueous solution from 72 to ≃27–32mN/m. However, the sol–gel technique using tetraethyl orthosilicate (TEOS) was used as a gentler method in order to entrap the P. aeruginosa MR01 cells in mold silica gels. Immobilized cells can be utilized several times in consecutive fermentation batches as well as in flow fermentation processes. In this way, reusability of the cells may lead to a more economical fermentation process. Approximately 90% of cell viability was retained during the silica sol-gel immobilization and ≃84% of viability of immobilized cells was preserved for 365days of immobilization and storage of the cells in phosphate buffer at 4°C and 25°C. Moreover, mold gels showed good mechanical stability during the seven successive fermentation batches and the entrapped cells were able to efficiently preserve their biosurfactant-producing potential.

Evaluation of cancer cell deformability by microcavity array

A cell entrapment device consisting of a microcavity array was used to analyze the deformability of MCF-10 human breast epithelial and MCF-7 human breast cancer cell lines by confocal laser scanning microscopy. Entrapment of up to 8 × 103 cells was achieved within 3 min. Protrusions were formed at the bottom surface of the array with a pore size of 3 μm. Protrusion length increased at higher filtration pressures and could be used to distinguish between MCF-7 and MCF-10 cells. These results indicate that our system is useful for high-throughput deformability analysis of cancer cells, which can provide insight into the mechanisms underlying tumor cell malignancy.

Unruptured Intradiploic Dermoid Cyst with Incomplete Dermal Sinus overlying Torcular Haerophili in an Adult Woman: Uncommon Location for Uncommon Lesion

Dermoid Cysts are rare lesions, accounting for about 1% of intracranial neoplasms, that involve mainly pediatric population; among the etiopathogenetical hypotheses there is an abnormal entrapment of the cells of the epithelial ectoderm in the neuroectoderm at the time of the closing of the neural tube. We report a rare case of simptomatic Dermoid Cyst with incomplete dermal sinus, placed on posterior cranial fossa overlying Torcular Haerophili, in a 33 year old woman, which has been treated surgically. We highlight the particular onset area of the lesion, its rise not in pediatric but in adult age and the lack of adhesion between the lesion and the surrounding tissues, whereas it frequently occurs in intracranial Dermoid Cysts. We express besides the necessity of surgical therapy even in absence of acute symptomatology, due to the risk of rupture and/or infection typical of such lesions.

Management Of Unexpected Peritoneal Metastases With Primary Colorectal Cancer Using Second-Look Surgery With HIPEC

Background: Peritoneal metastases (PM) will be unexpectedly present in approximately 10% of colorectal cancer patients having primary cancer resection. In the past this was considered to be an incurable condition with a terminal outcome. In patients determined to have peritoneal dissemination at the time of resection, the intervention was considered palliative. Recently, long term benefit from definitive treatment of PM with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has become a reality. These treatments are now appropriate for primary appendiceal and colorectal cancer determined to have PM at the time of resection. Methods: Modifications of the initial management of colorectal cancer patients found upon exploration to have PM are explored in this manuscript. In these patients, not only the primary cancer but also the PM must be optimally treated. Results: The presentation of the primary colon or rectal cancer as asymptomatic, bleeding, obstructed or perforated is important in treatment planning. The surgical approach must facilitate subsequent interventions to definitely treat PM. Procedures performed on the primary cancer are designed to minimize tumor cell entrapment. These patients usually have short course of systemic chemotherapy prior to repeat intervention with HIPEC. Conclusion: CRS and HIPEC must be integrated into the management of colorectal cancer patients who have PM identified unexpectedly at the time of primary cancer resection. Major resections in the absence of HIPEC should not occur in these patients in order to preserve an intact peritoneum as the first line of defense against PM and avoid tumor cell entrapment in subsequent CRS and HIPEC procedures.

Regional Perfusion in Sickle Cell Subjects and Normal Controls Is a Physiological Biomarker of Mental Stress and Fear of Pain

Introduction: Sickle cell disease (SCD) is a genetic disorder characterized by sudden onset of painful vaso-occlusive episodes (VOC) which can be triggered by stress as reported by sickle cell patients. The exact mechanism of VOC origin is not well understood; however, it could result as a progression of microvascular blockade with rigid sickled red blood cells (RBC). Anything that decreases regional blood flow (RBF) will increase the transit time that it takes the RBC to escape the microvasculature before it gets rigid and entrapped, thus increasing the chances of vaso-occlusion that may progress to VOC. The RBF is controlled by the autonomic nervous system (ANS) which is modulated by stress, and as we have previously shown, SCD patients have augmented autonomic mediated vasoconstriction response (VCR) to sigh and pain. Our studies showed significant VCR when subjects were told they were about to experience pain, suggesting that VCR might be the physiologic link between common VOC triggers like stress and sickled RBC retention in the microvasculature.Objectives: To study the effect of mental stress on autonomic parameters peripheral blood flow (PBF) and heart rate variability (HRV) in SCD.Methods: 19 SCD and 16 control (healthy and sickle cell trait) subjects were studied. Two standard mental stress tasks with graded levels of difficulty (N-back test and Stroop test) were presented to subjects using E-prime (Psychological software). Subjects were also exposed to a novel pain anticipation task, previously shown to induce VCR.PBF was measured using photo-plethysmography (PPG) on the left thumb. Reduction in PPG amplitude indicates vasoconstriction. Cardiac beat-to-beat variability (R-to-R interval;RRI) was extracted from electrocardiogram. ANS balance was derived from the following spectral indices of the RRI: high frequency power (HFP) ≈ parasympathetic activity, low frequency power (LFP), and the low/high ratio (LFP/HFP) representing sympathovagal balance.Average changes in PBF and HRV from the baseline were taken as the responses to the mental tasks.Results: There was a significant decrease in mean PBF, RRI and HFP during all the mental stressors (N-back test, Stroop test and pain fear) compared to the baseline (p<0.01). Based on task accuracy scores, there was clear difference in sublevels of task difficulty (p<0.0001). While PBF decreased during all the sublevels of N-back and Stroop compared to baseline (p<0.01), there was no PBF difference between the task sublevels. However, when subjects were told that they were about to experience severe pain from heat applied to their arm in a sham pain instruction that was given after N-back and Stroop, there was a significant decrease in PBF compared to baseline (p<0.001) and compared to the response during N-back (p<0.01). The parasympathetic withdrawal in response to mental tasks and fear of pain followed a similar pattern.Conclusions: Graded mental stress and fear of pain causes significant decrease in regional blood flow and parasympathetic withdrawal in SCD subjects and normal controls. The vasoconstriction response to "fear of pain" was significantly greater than the VRC caused by N-back and to a lesser extent in Stroop. The pattern of responses were not significantly different between SCD and controls however the consequences of decreased blood flow could be quite different because of the resulted entrapment of sickle cells in the microvasculature. This could explain how stress may play a role in the initiation of VOC in SCD by enhancing ANS mediated vasoconstriction, prolonging microvascular transit time and increasing the likelihood of vaso-occlusion.The 1st signal is mental tasks event marker, 2nd signal is photo-plethysmography (PPG) and the 3rd signal is heart rate variability derived from the electrocardiogram signal. [Display omitted] [Display omitted] DisclosuresWood:Celgene: Consultancy; AMAG: Consultancy; Ionis Pharmaceuticals: Consultancy; Vifor: Consultancy; Ionis Pharmaceuticals: Consultancy; Biomed Informatics: Consultancy; Vifor: Consultancy; World Care Clinical: Consultancy; World Care Clinical: Consultancy; Celgene: Consultancy; AMAG: Consultancy; Apopharma: Consultancy; Apopharma: Consultancy; Biomed Informatics: Consultancy.

Encapsulating role of β-cyclodextrin in formation of pickering water-in-oil-in-water (W1/O/W2) double emulsions containing Lactobacillus dellbrueckii

Lactobacillus dellbrueckii cultured in MRS and harvested in the late log phase was entrapped in the inner aqueous phase of a water-in-oil-in-water (W1/O/W2) Pickering emulsion stabilized by inclusion complexes having d32 of 3.6 μm formed from β-cyclodextrin (β-CD) and the results were compared to the corresponding double emulsions with Tween-80 as the secondary emulsifier. The stability of emulsions prepared at various primary emulsion contents and emulsifier concentrations was investigated. Emulsion morphology was observed by polarization microscopy and size distributions of dispersed droplets were examined to establish emulsion stability. The solid-like property of the test W1/O/W2 emulsions was found to dominate based on the oscillatory experiments results (G′>G″). The precipitated fraction obtained upon centrifugation of the emulsion phase was structurally characterized using 1H nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM) and the solid inclusion complex formation between β-CD and double emulsion contents was confirmed. The existence of L. dellbrueckii in β-CD containing emulsions was evidenced by Fourier transform infrared (FTIR) spectroscopy in ATR geometry and fluorescence microscopy. Moreover, the survival of the entrapped cells (initial number = 8.17 log CFU/ml) increased significantly with use of β-CD compared to Tween-80. It is concluded that the double emulsion prepared using β-CD protected L. dellbrueckii and the experimental findings of the present study are a fundamental guide for practical applications in food industry.

Comparative study on the biosorption of aluminum by free and immobilized cells of Bacillus safensis KTSMBNL 26 isolated from explosive contaminated soil

The study describes the sorption of aluminum by Bacillus safensis isolated from an explosive contaminate site. In a batch system, the optimum pH, temperature and contact time on biosorption of Al and cell growth were found to be 6.0, 35°C and 24h, respectively with initial metal concentration of 100mg/l Al. In immobilization studies, sodium alginate was used as supporting material for cell entrapment under optimized conditions. The variation in the protein banding pattern, functional groups and nature of Al treated and untreated bacterial cells were studied using SDS-PAGE, FTIR and XRD. While comparing the results of batch and immobilized sorption studies, the metal removal efficiency of free cells (92mg/l) was slightly higher than the immobilized cells (84mg/l). But the maintenance of high cell density, low processing cost, repeated and continuous uses are all recommends the immobilization technique for large scale water treatment.

Upgrading two-stage membrane bioreactor by bioaugmentation of Pseudomonas putida entrapment in PVA/SA gel beads in treatment of ciprofloxacin

The laboratory scale of the two-stage membrane bioreactor (2S-MBR) was investigated to find the optimal hydraulic retention times (HRT) in treatment of selected 10 antibiotics in real hospital wastewater. It showed that elimination of the antibiotics varied, depending upon antibiotic types and HRT. High biodegradation attributed to amoxicillin and clarithromycin. Fluoroquinolones/tetracycline adsorbed highly on anoxic (ANX) sludge, but tended to be biodegraded in the aerobic tank. Sulfamethoxazole/trimethoprim were mainly accumulated in the ANX/aerobic sludge. In order to increase biodegradation, 2S-MBR was upgraded to a three-stage MBR (3S-MBR) using the polyvinyl alcohol and sodium alginate (PVA/SA) beads of Pseudomonas putida (TISTR1522) in an entrapped cells reactor (ECR) as a pretreatment unit. Ciprofloxacin (CIP) in a synthetic wastewater was a refractory antibiotic for this feature investigation. It showed improvement of CIP degradation reached to 90% in 3S-MBR as compared to 58% of 2S-MBR. As a result, 24 CIP-transformed products (TPs) were detected. Additionally, 3S-MBR showed better efficacy of nitrogen removals. The SEM and FISH techniques revealed bacterial consortium in the system showing that the beads were well supported P. putida growth as well as synchronizing volume available for other bacteria. This feature makes P. putida being a potential microorganism for CIP biodegradation via bioaugmentation in 3S-MBR.

Polymeric Materials for Cell Microencapsulation.

Mammalian cells have been microencapsulated within both natural and synthetic polymers for over half a century. Specifically, in the last 36 years microencapsulated cells have been used therapeutically to deliver a wide range of drugs, cytokines, growth factors, and hormones while enjoying the immunoisolation provided by the encapsulating material. In addition to preventing immune attack, microencapsulation prevents migration of entrapped cells. Cells can be microencapsulated in a variety of geometries, the most common being solid microspheres and hollow microcapsules. The micrometer scale permits delivery by injection and is within diffusion limits that allow the cells to provide the necessary factors that are missing at a target site, while also permitting the exchange of nutrients and waste products. The majority of cell microencapsulation is performed with alginate/poly-L-lysine microspheres. Since alginate itself can be immunogenic, for cell-based therapy applications various groups are investigating synthetic polymers to microencapsulate cells. We describe a protocol for the formation of microspheres and microcapsules using the synthetic polymer poly(ethylene glycol) diacrylate (PEGDA).

Response of encapsulated cells to a gelatin matrix with varied bulk and microenvironmental elastic properties

Gelatin‐based hydrogels offer various biochemical cues that support encapsulated cells and are therefore suitable as cell delivery vehicles in regenerative medicine. However, besides the biochemical signals, biomechanical cues are crucial to ensure an optimal support of encapsulated cells. Hence, we aimed to correlate the cellular response of encapsulated cells to macroscopic and microscopic elastic properties of glycidylmethacrylate (GMA)‐functionalized gelatin‐based hydrogels. To ensure that different observations in cellular behavior could be attributed to differences in elastic properties, an identical concentration as well as degree of functionalization of biopolymers was utilized to form covalently crosslinked hydrogels. Elastic properties were merely altered by varying the average gelatin‐chain length. Hydrogels exhibited an increased degree of swelling and a decreased bulk elastic modulus G′ with prolonged autoclaving of the starting solution. This was accompanied by an increase of hydrogel mesh size and thus by a reduction of crosslinking density. Tougher hydrogels retained the largest amount of cells; however, they also interfered with cell viability. Softer gels contained a lower cell density, but supported cell elongation and viability. Observed differences could be partially attributed to differences in bulk properties, as high crosslinking densities interfere with diffusion and cell spreading and thus can impede cell viability. Interestingly, a microscopic elastic modulus in the range of native soft tissue supported cell viability and elongation best while ensuring a good cell entrapment. In conclusion, gelatin‐based hydrogels providing a soft tissue‐like microenvironment represent adequate cell delivery vehicles for tissue engineering approaches. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Application of multicriteria decision technique to determine optimum sodium alginate concentration for microencapsulation of Lactobacillus casei Shirota by extrusion and emulsification

AbstractThe aim of this study was to evaluate the effect of sodium alginate concentration on microencapsulation of probiotic Lactobacillus casei Shirota (LCS) by extrusion and emulsification methods and determine the optimum alginate concentration using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) approach. Determined morphology and size of the capsules, encapsulation efficiency, release of entrapped cells, and survivability of entrapped cell exposed heat treatment, simulated gastric and intestinal juice conditions were significantly varied depending on encapsulation method and alginate concentrations (p &lt; .05). The beads obtained with extrusion more protected the probiotic cells than beads obtained with emulsification. TOPSIS was performed to determine optimum alginate concentration regarding capsule size, encapsulation efficiency, release rate of entrapped cells, and survivability of entrapped cell exposed heat treatment, simulated gastric and intestinal juice conditions. According to TOPSIS, 2% and 2.5% of alginate may be effectively used to microencapsulation of LCS for extrusion and emulsification methods, respectively.Practical applicationsMicroencapsulation is a technology that is widely used for enclosed valuable core material in very small capsules with coating materials. The stability of microencapsulated probiotic bacteria is affected by several factors such as coating material and its concentration, microencapsulation methods, etc. The results of this work present the optimum sodium alginate concentration using TOPSIS for microencapsulation of Lactobacillus casei Shirota by extrusion and emulsification methods and present the ideal microencapsulation method.

Alginate/bacterial cellulose nanocomposite beads prepared using Gluconacetobacter xylinus and their application in lipase immobilization

Alginate/bacterial cellulose nanocomposite beads, with well-controlled size and regular spherical shapes, were prepared in a simple manner by entrapping Gluconacetobacter xylinus in barium alginate hydrogel beads, followed by cultivation of the entrapped cells in culture media with a low sodium ion concentration. The entire surface of the alginate hydrogel beads containing the cells was covered with cellulose fibers (∼30nm) after 36h of cultivation. The cellulose crystallinity index of the alginate/bacterial cellulose beads was 0.7, which was slightly lower than that of bacterial cellulose prepared by cultivating dispersed cells. The water vapor sorption capacity of the alginate/bacterial cellulose beads increased significantly from 0.07 to 38.00 (g/g dry bead) as cultivation time increased. These results clearly indicate that alginate/bacterial cellulose beads have a much higher surface area, crystallinity, and water-holding capacity than alginate beads. The immobilization of lipase on the surface of the nanocomposite beads was also investigated as a potential application of this system. The activity and specific activity of lipase immobilized on alginate/bacterial cellulose beads were 2.6- and 3.8-fold higher, respectively, than that of lipase immobilized on cellulose beads. The alginate/bacterial cellulose nanocomposite beads prepared in this study have several potential applications in the biocatalytic, biomedical, and pharmaceutical fields because of their biocompatibility, biodegradability, high crystallinity, and large surface area.

Dipolar Rings of Microscopic Ellipsoids: Magnetic Manipulation and Cell Entrapment

Dipolar particles are building blocks in several fields of science and technology, but making rings from interacting ferromagnetic colloids is challenging, due to strong thermal fluctuations at the microscale. This study shows that, under the right conditions, magnetic microparticles can $s\phantom{\rule{0}{0ex}}p\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}u\phantom{\rule{0}{0ex}}s\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}y$ form dipolar rings. The authors fabricate anisotropic hematite ellipsoids dispersed in water, which self-assemble into colloidal ribbons that transform into rings. These rings can be controlled with a static or oscillating magnetic field, to encircle, transport, and release a biological cell in a microfluidic device, for example.

Passive Entrapment of Tumor Cells Determines Metastatic Dissemination to Spinal Bone and Other Osseous Tissues.

During the metastatic process tumor cells circulate in the blood stream and are carried to various organs. In order to spread to different organs tumor cell—endothelial cell interactions are crucial for extravasation mechanisms. It remains unclear if tumor cell dissemination to the spinal bone occurs by passive entrapment of circulating tumor cells or by active cellular mechanisms mediated by cell surface molecules or secreted factors. We investigated the seeding of three different tumor cell lines (melanoma, lung and prostate carcinoma) to the microvasculature of different organs. Their dissemination was compared to biologically passive microbeads. The spine and other organs were resected three hours after intraarterial injection of tumor cells or microbeads. Ex vivo homogenization and fluorescence analysis allowed quantification of tumor cells or microbeads in different organs. Interestingly, tumor cell distribution to the spinal bone was comparable to dissemination of microbeads independent of the tumor cell type (melanoma: 5.646% ± 7.614%, lung: 6.007% ± 1.785%, prostate: 3.469% ± 0.602%, 7 μm beads: 9.884% ± 7.379%, 16 μm beads: 7.23% ± 1.488%). Tumor cell seeding differed significantly between tumor cells and microbeads in all soft tissue organs. Moreover, there were significant differences between the different tumor cell lines in their dissemination behaviour to soft tissue organs only. These findings demonstrate that metastatic dissemination of tumor cells to spinal bone and other osseous organs is mediated by passive entrapment of tumor cells similar to passive plugging of microvasculature observed after intraarterial microbeads injection.

Review of biological processes in oil sands: a feasible solution for tailings water treatment

The bitumen extraction process from Athabasca oil sands ore produces large quantities of toxic processed water as tailings. The oil industry has reduced the demand for fresh water in the extraction process by recycling this tailings water. Continual recycling increases the toxicity of tailings water many times over, and poses a serious threat to surface and groundwater quality. For a sustainable expansion of Canada’s oil sands industry, it is essential to develop a technically practicable and economically feasible tailings water treatment technology. A review was carried out to describe the integral role of biological processes in oil sands history for identifying a successor tailings water treatment technology. This study proposes the application of an entrapped cells system as a feasible solution for tailings water treatment. Bio-augmentation followed by entrapment of the microbial community indigenous to tailings ponds can be a promising tailings water treatment technology.