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process. Apatite-like nanoparticles were observed on the MBG–PCL surface after soaking for 4 h, and soaking for 24 h resulted in a MBG–PCL fully covered with apatite. Likewise, energy dispersive x-ray (EDX) analysis gave the same result. The biocompatibility of the MBG–PCL was evaluated by MTT [3-(4,5-Dimethyl thiazol-z-YI)-2,5-Diphenyltetrazolium Bromide] assay. The cell viability on the MBG–PCL surface was found to be significantly larger than that on the PCL surface. These studies demonstrate excellent bioactivity and biocompatibility of this MBG– PCL scaffold, the researchers said. The method developed in this work was used to fabricate a scaffold for tissue engineering. However, by utilizing alternative materials, the researchers showed that this method can be used in “applications involving biomedical devices, drug delivery systems, filters, catalysis, and optics.” CHANG ZHONG

Atomic Force Microscopy Used to Detect Cancer Cells Immunohistochemical and cytomorphological analyses are currently used to detect cancer cells, but morphological overlap between tumor and normal cell types often poses problems for these techniques. In the past few years, however, an increase in cell elasticity has been recognized as a marker for disease and associated with cell adhesion and cytoskeletal organization. S.E. Cross and J.K. Gimzewski at the California NanoSystems Institute and the University of California, Los Angeles, and Y.-S. Jin and J. Rao at the University of California, Los Angeles used atomic force microscopy (AFM) to distinguish cancerous cells from normal cells. As reported in a letter published in the December 2, 2007 issue of Nature Nanotechnology (p. 780; DOI:10.1038/nnano. 2007.388), the researchers used standard protocols to collect from patients with suspected metastatic adenocarcinoma samples of malignant and benign mesothelial cells in pleural effusions (adenocarcinoma is a cancer that originates in glandular tissue; mesothelial cells form part of the membranes covering body cavities, and an effusion is an abnormally large collection of fluid in the space surrounding the lungs). Ex vivo growth during a 12-h incubation period differentiated normal cells, which have a large, flat morphology, from benign cells, which exhibit anchorage-resistant morphology such as rounding. For each cell, elasticity was quantified as Young’s modulus E from force-displacement curves recorded from AFM performed at a rate of 1 Hz at 37˚C. Using samples from seven patients, average E values of 0.53 ±

0.10 kPa and 1.97 ± 0.70 kPa were obtained for 40 malignant and 48 benign mesothelial cells, respectively. Similar average E values were found for samples from a single patient, showing that the cell stiffness of metastatic cancer cells is about 73 ± 11% less than benign mesothelial cells. Malignant cells displayed a narrow distribution of E values while the benign cells displayed a broad peak. For one particular clinical sample consisting of cells that were difficult to classify as either benign or malignant, ex vivo culturing res