A computational framework for simulation of the delivery of substances into cells.

In this paper, we propose a simple computational framework for the rapid simulation of the delivery of substances into cells. Our approach treats the substances and the cell membrane as a collection of particles forming a discrete dynamical system, which is described by Newtonian equations in a purely mechanistic way. Detailed aspects about the modeling of particle interactions are discussed and resolved.

Analysis of patient-specific surgical ventricular restoration: importance of an ellipsoidal left ventricular geometry for diastolic and systolic function.

Surgical ventricular restoration (SVR) is a procedure designed to treat heart failure by surgically excluding infarcted tissues from the dilated failing left ventricle. To elucidate and predict the effects of geometrical changes from SVR on cardiac function, we created patient-specific mathematical (finite-element) left ventricular models before and after surgery using untagged magnetic resonance images. Our results predict that the postsurgical improvement in systolic function was compromised by a decrease in diastolic distensibility in patients.

Growth and remodeling of the left ventricle: A case study of myocardial infarction and surgical ventricular restoration.

Cardiac growth and remodeling in the form of chamber dilation and wall thinning are typical hallmarks of infarct-induced heart failure. Over time, the infarct region stiffens, the remaining muscle takes over function, and the chamber weakens and dilates. Current therapies seek to attenuate these effects by removing the infarct region or by providing structural support to the ventricular wall.

Fast, high-throughput creation of size-tunable micro/nanoparticle clusters via evaporative self-assembly in picoliter-scale droplets of particle suspension.

We report a fast, high-throughput method to create size-tunable micro/nanoparticle clusters via evaporative assembly in picoliter-scale droplets of particle suspension. Mediated by gravity force and surface tension force of a contacting surface, picoliter-scale droplets of the suspension are generated from a nanofabricated printing head. Rapid evaporative self-assembly of the particles on a hydrophobic surface leads to fast clustering of micro/nanoparticles and forms particle clusters of tunable sizes and controlled spacing.

Numerical modeling of stress in stenotic arteries with microcalcifications: a micromechanical approximation.

Most finite element models of atherosclerotic arteries do not account for the heterogeneity of the plaque constituents at the microscale. Failure of plaque lesions has been shown to be a local event, linked to stress concentrations caused by cap thinning, inflammation, macroscopic heterogeneity, and recently, the presence of microcalcifications. There is growing evidence that microcalcifications exist in the fibrous cap of plaque lesions.

Coffee-ring effect-based three dimensional patterning of micro/nanoparticle assembly with a single droplet.

We develop a novel patterning technique to create 3D patterns of micro and nanoparticle assembly via evaporative self-assembly based on the coffee-ring effect of an evaporating suspension. The principle of the technique is analyzed theoretically by the scaling analysis of main parameters of the process and the scaling effect, the effect of the volume, the concentration of the suspension, and the effect of surface treatment on the patterning are studied. On the basis of the presented technique, we demonstrate that the patterns of 3D assembly of various sizes of microparticles (Silica), metal oxide nanoparticles (TiO(2), ZnO), and metallic nanoparticles (Ag) can be successfully generated by low-concentrated particle suspension (1.

Ultrafast self-assembly of microscale particles by open-channel flow.

We developed an ultrafast microfluidic approach to self-assemble microparticles in three dimensions by taking advantage of simple photolithography and capillary action of microparticle-dispersed suspensions. The theoretical principles of high-speed assembly have been explained, and the experimental verifications of the assembly of various sizes of silica microspheres and silica gel microspheres within thin and long open microchannels by using this approach have been demonstrated. We anticipate that the presented technique will be widely used in the semiconductor and Bio-MEMS (microelectromechanical systems) fields because it offers a fast way to control 3D microscale particle assemblies and also has superb compatibility with photolithography, which can lead to an easy integration of particle assembly with existing CMOS (complementary metal oxide-semiconductor) and MEMS fabrication processes.