Structures in multicomponent polymer films : their formation, observation, applications in electronics and biotechnology

Several strategies to form multicomponent films of functional polymers, with micron, submicron and nanometer structures, intended for plastic electronics and biotechnology are presented. These approaches are based on film deposition from polymer solution onto a rotating substrate (spin-casting), a method implemented already on manufacturing lines. Film structures are determined with compositional (nanometer) depth profiling and (submicron) imaging modes of dynamic secondary ion mass spectrometry, near-field scanning optical microscopy (with submicron resolution) and scanning probe microscopy (revealing nanometer features). Self-organization of spin-cast polymer mixtures is discussed in detail, since it offers a one-step process to deposit and align simultaneously domains, rich in different polymers, forming various device elements: (i) Surface segregation drives self-stratification of nanometer lamellae for solar cells and anisotropic conductors. (ii) Cohesion energy density controls morphological transition from lamellar (optimal for encapsulated transistors) to lateral structures (suggested for light emitting diodes with variable color). (iii) Selective adhesion to substrate microtemplates, patterned chemically, orders lateral structures for plastic circuitries. (iv) Submicron imprints of water droplets (breath figures) decorate selectively micron-sized domains, and can be used in devices with hierarchic structure. In addition, selective protein adsorption to regular polymer micropatterns, formed with soft lithography after spin-casting, suggests applications in protein chip technology. An approach to reduce lateral blend film structures to submicron scale is also presented, based on (annealed) films of multicomponent nanoparticles

Solid variant of aneurysmal bone cyst of the heel: a case report

<p>Abstract</p> <p>Introduction</p> <p>An aneurysmal bone cyst is a benign but often rapidly expanding osteolytic multi-cystic osseous lesion that occurs as a primary, secondary, intra-osseous, extra-osseous, solid or conventional lesion. It frequently coexists with other benign and malignant bone tumors. Although it is considered to be reactive in nature, there is evidence that some aneurysmal bone cysts are true neoplasms. The solid variant of aneurysmal bone cyst is a rare subtype of aneurysmal bone cyst with a preponderance of solid to cystic elements. Such a case affecting the heel, an unusual site, is reported.</p> <p>Case presentation</p> <p>A 26-year-old Caucasian man presented with pain and swelling in his left lower extremity. A plain radiograph demonstrated an intra-osseous, solitary, eccentric mass in the front portion of the left heel. Computed tomography and magnetic resonance imaging scans showed that the lesion appeared to be sub-cortical, solid with a small cystic portion without the characteristic fluid-fluid level detection but with distinct internal septation. Bone images containing fluid-fluid levels are usually produced by aneurysmal bone cysts. The fluid-fluid level due to bleeding within the tumor followed by layering of the blood components based density differences, but it was not seen in our case. An intra-lesional excision was performed. Microscopic examination revealed fibrous septa with spindle cell fibroblastic proliferation, capillaries and extensive areas of mature osteoid and reactive woven bone formation rimmed by osteoblasts. The spindle cells had low mitotic activity, and atypical forms were absent. The histological features of the lesion were consistent with the solid variant of an aneurysmal bone cyst.</p> <p>Conclusion</p> <p>Solid aneurysmal bone cysts have been of great interest to pathologists because they may be mistaken for malignant tumors, mainly in cases of giant cell tumors or osteosarcomas, because of cellularity and variable mitotic activity. It is rather obvious that the correlation of clinical, radiological and histological findings is necessary for the differential diagnosis. The eventual diagnosis is based on microscopic evidence and is made when a predominance of solid to cystic elements is found. The present case is of great interest because of the nature of the neoplasm and the extremely unusual location in which it developed. Pathologists must be alert for such a diagnosis.</p

Differentiation between single bladder cancer cells using principal component analysis of time-of-flight secondary ion mass spectrometry

Time-of-flight-secondary ion mass spectrometry (TOF-SIMS) mass spectra measurements combined with an appropriate sample preparation protocol are the powerful tools to obtain unique information about the chemical composition of biological materials. In our studies, two questions were addressed, i.e., whether it is possible to develop a fixative-based sample preparation protocol and whether it allows one to distinguish between cells originating from various stages of cancer progression. Therefore, four human bladder cancer cell lines (with distinct malignancy degree) have been investigated. A chemical fixation protocol has been used for TOF-SIMS measurements, and mass spectra were obtained using a Bi_{3}+ primary ion beam. The principal component analysis (PCA) has been applied to analyze the whole range of mass spectra (without preselection of any particular masses) using two approaches of data preprocessing, namely, mean centering and autoscaling. The PC3 versus PC2 plot has showed significant differences between nonmalignant cancer cells and the cancerous ones for both of preprocessing approaches. The analysis of mass spectra of human bladder cells allows one to find a list of mass peaks with intensities significantly larger in cancerous bladder cells compared to nonmalignant cell cancer of the ureter (HCV29 cells). These findings show that TOF-SIMS in combination with PCA can be used to identify reference, human bladder cells from cancerous ones