Search

Cellular adhesiveness to biomaterial is one of the important properties for the success of tissue engineering. The cell-biomaterial interactions involve close cooperation of adhesion proteins, plasma membrane, and cytoskeletons to form focal adhesions during the process of anchoring. Dynamic development of the plasma membrane in the process reflects the cellular biocompatibility and motility. The process of cell attachment beginning from seeding, contact, attachment, and spreading has not been investigated. In this study, we monitored the whole process of cells attaching to the substrate surface by time-lapse confocal microscopy. We observed that the surface configuration of the substratum effects plasma membrane expansion and genomic materials distribution. In contrast to the cells grown on the plate, the cells attached on pillars are with rounded nuclei and with prominent lamellipodia spreading out. Membrane expansion is involved in dynamic development of the plasma membrane and lamellipodia formation for attachment, migration, or proliferation and reflects the cellular physiology status of the cells. This study provides a platform for investigation of cell behavior and dynamic development of subcellular structures regarding cell-biomaterial interactions. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1149-1154, 2014. [ABSTRACT FROM AUTHOR]

Understanding neurite outgrowth, orientation, and migration is important for the design of biomaterials that interface with the neuronal tissue. Micropatterns can significantly influence neurite outgrowth, neurite length, orientation, extracellular matrix expression, neuron differentiation, and migrating velocity. We analyzed the neuritogenesis and neurite outgrowth of PC12 cells in three-dimensional Si wafer with various micropatterns fabricated using photolithography and etching techniques. When nerve growth factor was added into culture medium, PC12 cells started to grow neurites. Extended neurites were significantly affected by different patterns and displayed higher growth-associated protein-43 expression. Cellular performance including growth rate, bipolar phenotype elongation, neurite extension, and growth-associated protein-43 expression of the PC12 cells with a differentiated character are higher on a grooved substrate. However, the grooved pattern can restrict the motility of PC12 cells and decrease the velocity of cellular movement. The average of the number of neurites per cell is the highest on the pillar substrate, but their neurite length is the shortest. In contrast, actin and lamimin expression, motion track, angular deviation, and movement velocity of PC12 cells are most excellent on the planar Si wafer. These findings confirmed that topographical features can cooperatively act with nerve growth factor, signaling the regulation of the formation of neurites. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:185-194, 2013. [ABSTRACT FROM AUTHOR]

In this paper, we describe a simple one-pot method, employing l-3,4-dihydroxyphenylalanine (L-DOPA) as a reducing/capping reagent, for the synthesis of fluorescent gold nanoclusters (AuNCs). Within a short reaction time of 15 min (excluding the time required for purification), this strategy allows the fabrication of homogeneous AuNCs having the capability to sense ferric ions (Fe(3+)). The as-prepared AuNCs exhibited a fluorescence emission at 525 nm and a quantum yield of 1.7%. On the basis of an aggregation-induced fluorescence quenching mechanism, these fluorescent AuNCs offer acceptable sensitivity, high selectivity, and a limit of detection of 3.5 μM for the determination of Fe(3+) ions, which is lower than the maximum level (0.3 mg L(-1), equivalent to 5.4 μM) of Fe(3+) permitted in drinking water by the U.S. Environmental Protection Agency.

Fibroblasts alter their mode of attachment and focal contact when placed on square arrays of silicon pillars. The pillars had 1-microm diameters with identical surface chemistry. Distance between pillars is 9 microm and height of pillars is 1, 5, or 10 microm on substrates. We found that these micropillars, rather than specific interactions, provided more opportunities for mechanical interlocking of the fibroblasts and acted as physical barriers that restrained cell migration. The cellular morphology and behavior is guidable by the height of pillars. In some cases, the fibroblasts filled in the intervals among several pillars; in others, a pillar protruded visibly through the cell body but did not pierce it, the cells were survived. Therefore, fibroblasts were immobilized upon in situ and the cytoplasma migrated outward to the bottom of the substrate subsequently. Laminin plays a critical role in cell attachment to the basement membrane. The results of laminin expression in fibroblasts suggest that pillar pattern appears to change cellular behavior and affect laminin expression significantly., ((c) 2009 Wiley Periodicals, Inc.)