Mechanical models of the cellular cytoskeletal network for the analysis of intracellular mechanical properties and force distributions: a review.

The cytoskeleton, which is the major mechanical component of cells, supports the cell body and regulates the cellular motility to assist the cell in performing its biological functions. Several cytoskeletal network models have been proposed to investigate the mechanical properties of cells. This review paper summarizes these models with a focus on the prestressed cable network, the semi-flexible chain network, the open-cell foam, the tensegrity, and the granular models.

Targeted RGD nanoparticles for highly sensitive in vivo integrin receptor imaging.

A new magnetic resonance imaging (MRI) contrast bearing RGD peptide is reported. In this study, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles with various sizes were prepared. Particles sizes between 6 and 13 nm were tuned by varying the stirring rate.

Complexity of the tensegrity structure for dynamic energy and force distribution of cytoskeleton during cell spreading.

Cytoskeleton plays important roles in intracellular force equilibrium and extracellular force transmission from/to attaching substrate through focal adhesions (FAs). Numerical simulations of intracellular force distribution to describe dynamic cell behaviors are still limited. The tensegrity structure comprises tension-supporting cables and compression-supporting struts that represent the actin filament and microtubule respectively, and has many features consistent with living cells.

Targeted Herceptin-dextran iron oxide nanoparticles for noninvasive imaging of HER2/neu receptors using MRI.

A novel magnetic resonance imaging (MRI) contrast agent containing Herceptin is reported. The surfaces of superparamagnetic iron oxide nanoparticles were modified with dextran and conjugated with Herceptin (Herceptin-nanoparticles) to improve their dispersion, magnetization, and targeting of the specific receptors on cells. From analytical results, we found that Herceptin-nanoparticles were well dispersed in solutions of various pH range, and had no hysteresis, high saturation magnetization (80 emu/g), and low cytotoxicity to a variety of cells.

Targeted folic acid-PEG nanoparticles for noninvasive imaging of folate receptor by MRI.

The surface of superparamagnetic iron oxide nanoparticles (SPIO) with different molecular weight of poly(ethylene glycol) (PEG) and folic acid (FA) were synthesized. The SPIO-PEG-FA nanoparticles are well-dispersed and have good stability in various pH solutions. The lack of hysterestis and remanence at ambient temperatures is characteristic of superparamagnetic materials for SPIO-PEG-FA.