Interactions between cancer cells and inorganic materials

Cancer is a complex multi-faceted disease that poses a significant threat to world health. However, as our understanding of the disease improves so does the complexity of this threat. One aspect of complexity is tumour heterogeneity, subpopulations of which have been identified as being fundamental to the understanding the formation, progression and treatment of the disease. Cancer stem cells and cells undergoing epithelial to mesenchymal transition are two such subpopulations. However, the study of these populations is complicated by difficulties in the isolation and sustainment of these cell types in vitro due to the scarcity and transience of their nature. The importance of the cells local environment or ‘niche’ in driving cell responses has been made increasingly apparent in recent years, specifically the role of the surfaces to which the cell is in contact. Many cellular processes, even the survival of the cell itself, have been shown to be dependent on cues taken from the surface and the biological entities (proteins etc.) which can interact with surfaces independently of the cell. This understanding opens the possibility that surface chemistry can be applied to the precise control of cells for specific applications. Using this premise, this work developed a range of surface materials based around silica which are both compatible with in vitro culture and capable of presenting a range of surface chemistries (hydroxyl, methyl. phenyl, amino) to which the cell response in terms of proliferation, adhesion, motility and morphology was measured. Specific surfaces determined from these assays where then examined to explore the influence of surface chemistry on the sub-populations of the human prostate cell line OPCT1

Fabrication, characterisation and performance of hydrophilic and super-hydrophilic silica as cell culture surfaces

We demonstrate a straightforward procedure for the controlled formation of silica films on tissue culture polystyrene (PS) surfaces. The films were formed by sequentially treating PS with polyaniline, glutaric dialdehyde and protein prior to silica formation. The films could be tailored to exhibit superhydrophilicity (contact angle < 5°) which was retained for more than two months under ambient conditions. Both hydrophilic and super-hydrophilic silica coated surfaces were suitable for the culture of an adherent human melanoma cell line. Proliferation, toxicity and adhesion assays were used to compare cell behaviour. Cells on the silica surfaces showed enhanced adhesion and comparable rates of cell proliferation as compared to cells grown on conventional tissue culture plastic. The results obtained can be understood by considering the surface properties of the different materials and the ability of the silica coated surfaces to adsorb significantly higher levels of serum proteins from the growth medium. One of the outcomes of this study is a re-evaluation of the hydrophobicity/hydrophilicity characteristics required for good cell growth and the possibility of designing new tissue culture materials capable of greater control over cell populations

Traditional materials from new sources – conflicts in analytical methods for calcium carbonate

Calcium carbonate, (E170) is a common food and pharmaceutical additive/ingredient. In addition to a source of calcium, the carbonate has uses including as a colour, acidity regulator and bulking agent. Globally, a range of regulatory agencies and pharmacopoeia control the analyses and specification of additives in food, supplements, pharmaceutical substances and excipients. Accordingly, a range of specifications and analyses exist for calcium carbonate depending on the application and market of the product. In this contribution, we analyse calcium carbonates from geological, synthetic and biogenic sources, focussing on acid insoluble impurities, a test required by current monographs. Analysis of calcium carbonate from different origins may require modification of existing tests to comply with regulatory bodies, due to the variation of impurities specific to the source of the material. We suggest an analytical approach involving centrifugation that improves analytical efficiency (up to 85% time reduction), especially for calcium carbonate of biological origin

Triethylphosphite as a network forming agent enhances in-vitro biocompatibility and corrosion protection of hybrid organic-inorganic sol-gel coatings for Ti6Al4V alloys

The biocompatibility and life of metallic implants can be enhanced through improving the biocompatibility and corrosion protection characteristics of the coatings used with these materials. In this study, triethylphosphite (TEP) was used to introduce phosphorus into organic-inorganic hybrid silica based sol gel coatings prepared using γ-methacryloxypropyltrimethoxysilane and tetramethylorthosilicate. Addition of TEP dramatically increased the rate of intermolecular condensation and resulted in materials showing greater cross linking. Protein (fibrinogen) uptake, osteoblast in vitro biocompatibility and corrosion resistance was enhanced in coatings containing TEP. Although higher concentrations of phosphorus supported the greatest improvement in biocompatibility, a compromise in the phosphorus concentration used would be required if corrosion resistance was most desirable parameter for optimisation. Films prepared by dip coating on Ti6Al4V alloys from these sols offer a promising alternative to wholly metallic prostheses

Materials-based approach for interrogating human prostate cancer cell adhesion and migratory potential using a fluoroalkylsilica culture surface

OPCT-1 is a heterogeneous prostate cancer cell line derived from primary (rather than metastatic) disease which contains epithelial, mesenchymal, and CD44 high/CD24 low cancer stem cell (CSC) subpopulations and from which we have previously generated and characterized stable mesenchymal (P4B6B) and epithelial (P5B3) cell subpopulations. In this contribution, we explore the effect of tissue culture surface chemistry (standard tissue culture plastic (TCP) and a fluoroalkylsilica (FS) culture surface with inherently low surface energy) on the phenotype and adherent capacity of mesenchymal and epithelial cell populations. We demonstrate that OPCT-1 cells adherent to FS surfaces comprise both epithelial- and mesenchymal-like populations; a mesenchymal subpopulation derived from OPCT1 (P4B6B) poorly adheres to FS and formed spheroids, whereas an epithelial subpopulation derived from OPCT1 (P5B3) forms an adherent monolayer. In contrast, P4B6B cells do adhere to FS when cocultured with P5B3 cells. Taken together, these findings demonstrate that EMT/cell differentiation status dictates cell adhesive capacity and provide a novel insight into the relationship between epithelial and mesenchymal cell populations in metastasis. Importantly, the differences in adherence capacity between P4B6B and P5B3 are not apparent using standard TCP-based culture, thereby highlighting the value of using alternative culture surfaces for studying cell surface interaction/adhesion phenomena and interrogating mechanisms involved in adhesion and detachment of metastatic tumor cells

Fluorescently-tagged polyamines for the staining of siliceous materials

Siliceous frustules of diatom algae contain unique long-chain polyamines, including those having more than six nitrogen atoms. These polyamines participate in the formation of the siliceous frustules of the diatoms but their precise physiological role is not clear. The main hypotheses include formation of a polyamine and polyphosphate supramolecular matrix. We have synthesized novel fluorescent dyes from a synthetic oligomeric mixture of polyamines and the fluorophore 7-nitro-2,1,3-benzoxadiazole. The long polyamine chain ensures the high affinity of these dyes to silica, which allows their application in the staining of siliceous materials, such as valves of diatom algae and fossilized samples from sediments. The fluorescently stained diatom valves were found to be promising liquid flow tracers in hydrodynamic tests. Furthermore, complexation of the polyamine component of the dyes with carbonic polymeric acids results in changes to the visible spectrum of the fluorophore, which allows study of the stability of the complex vs the length of the polyamine chain. Using poly (vinyl phosphonic acid) as a model for phosphate functionality in silaffins (a potential matrix in the formation of biogenic silica) little complexation with the polyamine fluorophores was observed, bringing into question the role of a polyamine - polymeric phosphate matrix in biosilicification

Organic-inorganic hybrid coatings containing phosphorus precursors prepared by sol–gel on Ti6Al4V alloy: electrochemical and in-vitro biocompatibility evaluation

The durability and long-term success of metallic implants are enhanced through the molecular scale design of biocompatible and corrosion resistant surface coatings. To pursue this hypothesis, we have developed a new class of organic-inorganic (O-I) hybrid nanocomposite coatings based on tetramethylorthosilicate (TMOS) and γ-methacryloxypropyltrimethoxysilane (MAPTMS) as organofunctional alkoxysilanes precursors and dimethyltrimethylsilylphosphite (DMTMSP) as a phosphorus precursor. Addition of DMTMSP to TMOS-MAPTMS hybrids increased the extent of intermolecular condensation and cross-linking observed. Both normal human osteoblast in-vitro biocompatibility and corrosion resistance were enhanced in coatings containing DMTMSP. Though increasing phosphorous content correlated with biocompatibility, a compromise in the amount of phosphorus incorporated would be required if corrosion resistance was the most desirable parameter for optimization, at least for single coat systems. Evaluation of the electrochemical behaviour and the in-vitro biocompatibility show that films prepared using these materials by dip coating onto Ti6Al4V alloys offer a promising alternative to simpler coatings and wholly metallic prostheses

Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

Primary care provider perceptions of intake transition records and shared care with outpatient cardiac rehabilitation programs

Abstract Background While it is recommended that records are kept between primary care providers (PCPs) and specialists during patient transitions from hospital to community care, this communication is not currently standardized. We aimed to assess the transmission of cardiac rehabilitation (CR) program intake transition records to PCPs and to explore PCPs' needs in communication with CR programs and for intake transition record content. Method 144 PCPs of consenting enrollees from 8 regional and urban Ontario CR programs participated in this cross-sectional study. Intake transition records were tracked from the CR program to the PCP's office. Sixty-six PCPs participated in structured telephone interviews. Results Sixty-eight (47.6%) PCPs received a CR intake transition record. Fifty-eight (87.9%) PCPs desired intake transition records, with most wanting it transmitted via fax (n = 52, 78.8%). On a 5-point Likert scale, PCPs strongly agreed that the CR transition record met their needs for providing patient care (4.32 ± 0.61), with 48 (76.2%) reporting that it improved their management of patients' cardiac risk. PCPs rated the following elements as most important to include in an intake transition record: clinical status (4.67 ± 0.64), exercise test results (4.61 ± 0.52), and the proposed patient care plan (4.59 ± 0.71). Conclusions Less than half of intake transition records are reaching PCPs, revealing a large gap in continuity of patient care. PCP responses should be used to develop an evidence-based intake transition record, and procedures should be implemented to ensure high-quality transitional care

Measurement of Contractile Stress Generated by Cultured Rat Muscle on Silicon Cantilevers for Toxin Detection and Muscle Performance Enhancement

Background: To date, biological components have been incorporated into MEMS devices to create cell-based sensors and assays, motors and actuators, and pumps. Bio-MEMS technologies present a unique opportunity to study fundamental biological processes at a level unrealized with previous methods. The capability to miniaturize analytical systems enables researchers to perform multiple experiments in parallel and with a high degree of control over experimental variables for high-content screening applications.Methodology/Principal Findings: We have demonstrated a biological microelectromechanical system (BioMEMS) based on silicon cantilevers and an AFM detection system for studying the physiology and kinetics of myotubes derived from embryonic rat skeletal muscle. It was shown that it is possible to interrogate and observe muscle behavior in real time, as well as selectively stimulate the contraction of myotubes with the device. Stress generation of the tissue was estimated using a modification of Stoney's equation. Calculated stress values were in excellent agreement with previously published results for cultured myotubes, but not adult skeletal muscle. Other parameters such as time to peak tension (TPT), the time to half relaxation (KRT) were compared to the literature. It was observed that the myotubes grown on the BioMEMS device, while generating stress magnitudes comparable to those previously published, exhibited slower TPT and KRT values. However, growth in an enhanced media increased these values. From these data it was concluded that the myotubes cultured on the cantilevers were of an embryonic phenotype. The system was also shown to be responsive to the application of a toxin, veratridine.Conclusions/Significance: The device demonstrated here will provide a useful foundation for studying various aspects of muscle physiology and behavior in a controlled high-throughput manner as well as be useful for biosensor and drug discovery applications