Design of a high-throughput bio-ferrograph for isolation of cancer cells from whole blood

Enumeration and morphological characterization of circulating tumor cells (CTCs) can be useful in diagnosis and prognosis of metastatic cancer patients. The bio-ferrograph (BF) with its five flow channels, which was developed in the late 1990s for magnetic isolation of biological cells and tissue fragments from fluids, is a modification of the analytical ferrograph. Its use for isolation of rare CTCs from human whole blood (HWB) is a novel approach for the detection of cancer at a cellular level. The isolation process is facilitated by the interaction of specifically magnetized cells with a strong external magnetic field, yielding high recovery rates with no morphological alternation of cells that are isolated on a coverslip glass slide, thus allowing complementary microscopic, chemical, biological, and mechanical analyses. Here, a full mechanical and magnetostatic design of a novel high-throughput BF is presented. The system design is based on an optimized procedure for bio-ferrographic isolation of CTCs from HWB. It incorporates a semi-automated CTC separation system consisting of sample preparation, labeling, and staining; magnetic isolation; and system recovery. The design process was optimized based on experimental feasibility tests and finite element analyses. The novel bench-top system consists of 100 flow channels, allowing simultaneous analysis of multiple samples from 20 patients in each run, with the potential to become a decision-making tool for medical doctors when monitoring patients in a hospital setting. It opens a new route for early diagnosis, prognosis, and treatment of cancers, as well as other diseases, such as osteoarthritis.

Assisted deposition of nano-hydroxyapatite onto exfoliated carbon nanotube oxide scaffolds

Electrodeposited nano-hydroxyapatite (nHAp) is more similar to biological apatite in terms of microstructure and dimension than apatites prepared by other processes. Reinforcement with carbon nanotubes (CNTs) enhances its mechanical properties and increases adhesion of osteoblasts. Here, we carefully studied nHAp deposited onto vertically aligned multi-walled CNT (VAMWCNT) scaffolds by electrodeposition and soaking in a simulated body fluid (SBF). VAMWCNTs are porous biocompatible scaffolds with nanometric porosity and exceptional mechanical and chemical properties. The VAMWCNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method, and then oxidized and exfoliated by oxygen plasma etching (OPE) to produce graphene oxide (GO) at the VAMWCNT tips. The attachment of oxygen functional groups was found to be crucial for nHAp nucleation during electrodeposition. A thin layer of plate-like and needle-like nHAp with high crystallinity was formed without any need for thermal treatment. This composite (henceforth referred to as nHAp-VAMWCNT-GO) served as the scaffold for in vitro biomineralization when soaked in the SBF, resulting in the formation of both carbonate-rich and carbonate-poor globular-like nHAp. Different steps in the deposition of biological apatite onto VAMWCNT-GO and during the short-term biomineralization process were analysed. Due to their unique structure and properties, such nano-bio-composites may become useful in accelerating in vivo bone regeneration processes.

Influence Of Hydrogen On The Thermal Stability Of Zr-Based Quasicrystals

The high number of tetrahedrally coordinated sites for interstitial hydrogen and the favorable hydrogen-metal chemistry make quasicrystalline Zr-Cu-Ni-Al alloys a candidate for hydrogen storage applications. The icosahedral phase in Zr69.5Cu12Ni11Al7.5 has been shown to absorb electrochemically hydrogen up to H/M = 1.6. Only partially desorption of hydrogen was observed by TDA at about 500°C. Since hydrogen desorption seems to be hindered by a surface barrier, the hydrogen remains in the quasicrystal thus influencing their thermal stability. Such effects of hydrogen were studied by DSC and microstructural investigations. With increasing hydrogen content the decomposition of icosahedral Zr69.5. Cu12Ni11A17.5 is shifted to lower temperatures. Quasicrystals decompose by a discontinous transformation into the tetragonal Zr2Cu phase, the tetragonal Zr2Ni and the hexagonal Zr6NiAl2. Hydrogenation does not influence the phases formed during decomposition, but leds to the formation of a finer microstructure. We assume that the defects formed during the hydrogenation accelerate the nucleation of the stable crystalline phase.

Hydrogenation and Crystallization of Zr-Cu-Ni-Al Glasses

Zr-Cu-Ni-Al belongs to the best glass forming systems known. Hydrogen charging was performed electrochemically in a 2:1 glycerin-phosphoric acid electrolyte. In comparison to binary Zr-Ni glasses the absorption kinetics in amorphous Zr-Cu-Ni-Al were found to be slower, but the storage capacity is similar. Desorption is hindered by the formation of thin ZrO2 layers. Partial replacement of Ni by Pd in an amorphous Zr68 5Cu13Ni11Al7.5 alloy was found to change the absorption behavior to a faster kinetic and to improve the desorption. The influence of hydrogen on the thermal stability was studied by DSC as well as by xray diffraction and TEM. Hydrogen was observed to play an important role. With increasing H/M ratio amorphous Zr69.5Cu12Ni11Al7.5 was found to transform during annealing above the glass transition temperature into a quasicrystalline structure with decreasing grain size until a nanocrystalline microstructure is achieved. Above a hydrogen content of H/M = 0.05 instead of quasicrystals a tetragonal phase with lattice parameters close to those of Zr2Ni is formed. At very high hydrogen contents phase separation is assumed to take place followed by the formation of nanocrystalline ZrH2 and other phases with reduced Zr content.

POSS-Polyimide Nanocomposite Films: Simulated Hypervelocity Space Debris and Atomic Oxygen Effects

The combined effect of hypervelocity space debris impact and atomic oxygen (AO) attack on the degradation of reinforced polyhedral oligomeric silsesquioxanes (POSS)-polyimide films was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km s -1. The impacted films were exposed to an RF-plasma source, which was used to simulate the effect of AO in the low Earth orbit. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to air RF-plasma, the impacted POSS-free film revealed a synergistic effect associated with a large increase in the erosion rate while impacted POSS-containing samples showed improved erosion resistance. The increased erosion rate of the impacted POSS-free film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen.

A new Ti-5Ag alloy for customized prostheses by three-dimensional printing (3DP)

Three important considerations in the fabrication of customized cranio-maxillofacial prostheses are geometric precision, material strength, and biocompatibility. Three-dimensional printing (3DP) is a rapid part-fabrication process that can produce complex parts with high precision. The aim of this study was to design, synthesize by 3DP, and characterize a new Ti-5Ag (wt%) alloy. Silver nitrate was found to be an appropriate inorganic binder for the Ti powder-based skeleton, and the optimum sintering parameters for full densification were determined. The hardness of the Ti-5Ag alloy was shown to be much higher than that of a pure titanium sample. Potentiodynamic measurements, carried out in saline solution at body temperature, showed that the Ti-5Ag alloy had good passivation behavior, similar to that of pure titanium. It is concluded that the Ti-Ag system may be suitable for fabrication of customized prostheses by 3DP.