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ABSTRACT: ABSTRACT: A comparative study of immature and mature bone marrow-derived dendritic cells (BMDCs) was first performed through an atomic force microscope (AFM) to clarify differences of their nanostructure and adhesion force. AFM images revealed that the immature BMDCs treated by granulocyte macrophage-colony stimulating factor plus IL-4 mainly appeared round with smooth surface, whereas the mature BMDCs induced by lipopolysaccharide displayed an irregular shape with numerous pseudopodia or lamellapodia and ruffles on the cell membrane besides becoming larger, flatter, and longer. AFM quantitative analysis further showed that the surface roughness of the mature BMDCs greatly increased and that the adhesion force of them was fourfold more than that of the immature BMDCs. The nano-features of the mature BMDCs were supported by a high level of IL-12 produced from the mature BMDCs and high expression of MHC-II on the surface of them. These findings provide a new insight into the nanostructure of the immature and mature BMDCs.
Nanoscale Research Letters 01/2011; 6(1):455. · 2.73 Impact Factor
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ABSTRACT: Although CD69 is well known as an early T cell-activation marker, the possibility that CD69 are distributed as nano-structures on membrane for immune regulation during T cell activation has not been tested. In this study, nanoscale features of CD69 expression on activated T cells were determined using the atomic force microscopy (AFM) topographic and force-binding nanotechnology as well as near-field scanning optical microscopy (NSOM)-/fluorescence quantum dot (QD)-based nanosacle imaging. Unstimulated CD4(+) T cells showed neglectable numbers of membrane CD69 spots binding to the CD69 Ab-functinalized AFM tip, and no detectable QD-bound CD69 as examined by NSOM/QD-based imaging. In contrast, Phytohemagglutinin (PHA)-activated CD4(+) T cells expressed CD69, and displayed many force-binding spots binding to the CD69 Ab-functionalized AFM tip on about 45% of cell membrane, with mean binding-rupture forces 276 +/- 71 pN. Most CD69 molecules appeared to be expressed as 100-200 nm nanoclusters on the membrane of PHA-activated CD4(+) T cells. Meanwhile, NSOM/QD-based nanoscale imaging showed that CD69 were non-uniformly distributed as 80-200 nm nanoclusters on cell-membrane of PHA-activated CD4(+) T cells. This study represents the first demonstration of the nano-biology of CD69 expression during T cell activation.
Journal of Molecular Recognition 09/2009; 22(6):516-20. · 3.31 Impact Factor
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ABSTRACT: Alternations of lymphocyte in biophysical properties (e.g., morphology and viscoelasticity) are related to the human health, disease diagnosis and treatment. Here, we used atomic force microscopy (AFM) to characterize the morphology and mechanical properties of normal lymphocyte and Jurkat. The AFM images revealed that their cell shapes appeared similar. The mechanical properties of the two groups were tracked with AFM-based force spectroscopy. The normal lymphocyte cells had a high adhesion force distribution in (796.7 +/- 248.5) pN, whereas the Jurkat cells had a low force distribution in (158.5 +/- 37.5) pN. The adhesion force revealed that the Young's modulus of normal lymphocyte cells (0.471 kPa +/- 0.081 kPa) was nearly four times higher than that of Jurkat cells (0.0964 kPa +/- 0.0229 kPa) at the same loading rate. The stiffness of normal lymphocyte cells was (2.278 +/- 0.488) mN/m and that of Jurkat cells was (4.322 +/- 0.382) mN/m. The differences in mechanical properties of normal and cancerous cells were obvious that healthy and diseased states could be clearly distinguished. These results may be applied to the clinic disease diagnosis for distinguishing the normal cells from the cancer ones even when they show similar shapes.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 07/2009; 25(7):1107-12.
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ABSTRACT: The ultrastructural and mechanical properties of single resting, activated and apoptosis lymphocyte have been investigated by atomic force microscopy (AFM). Using topographic imaging, we showed that the surface of the resting lymphocyte is smooth, while lymphocyte activation and apoptosis are often accompanied by changes in cell morphology. The apoptosis lymphocyte is rougher than those of the two other morphotypes, and coated with many big particles. Using spatially resolved force-distance curves, we found that the valve of the activated lymphocyte is about two to three times stiffer (Young's modulus of approximately 20 kPa) than those of the two other morphotypes (5-11 kPa). These results can improve our understanding of the mechanical properties of cells during growth and differentiation.
Journal of biomechanics 06/2009; 42(10):1513-9. · 2.66 Impact Factor
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ABSTRACT: Atomic force microscope (AFM) was used to study biotoxicity of food preservative sodium benzoate (SB) at the single cellular level. Lymphocyte morphology and membrane ultrastructure treated with SB at different concentrations and time were analyzed visually. As compared to the normal lymphocyte, the cell morphology and membrane was significantly changed and its ultrastructure was also complicated. After treated with SB, the Rp-v, Rq, Ra and Z values were changed. The statistical analysis of lymphocytes after treated with SB was studied, and discussed its mechanism.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 09/2008; 24(8):1428-32.
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ABSTRACT: To date, nanoscale imaging of the morphological changes and adhesion force of CD4(+) T cells during in vitro activation remains largely unreported. In this study, we used atomic force microscopy (AFM) to study the morphological changes and specific binding forces in resting and activated human peripheral blood CD4(+) T cells. The AFM images revealed that the volume of activated CD4(+) T cells increased and the ultrastructure of these cells also became complex. Using a functionalized AFM tip, the strength of the specific binding force of the CD4 antigen-antibody interaction was found to be approximately three times that of the unspecific force. The adhesion forces were not randomly distributed over the surface of a single activated CD4(+) T cell, indicated that the CD4 molecules concentrated into nanodomains. The magnitude of the adhesion force of the CD4 antigen-antibody interaction did not change markedly with the activation time. Multiple bonds involved in the CD4 antigen-antibody interaction were measured at different activation times. These results suggest that the adhesion force involved in the CD4 antigen-antibody interaction is highly selective and of high affinity.
Biochemical and Biophysical Research Communications 08/2008; 374(1):90-4. · 2.48 Impact Factor
