Nanoinjection lance arrays have been used to inject propidium iodide, a dye, into living cells. The lance arrays consist of approximately four million needle-like structures on a 2 × 2 cm silicon chip, fabricated using standard methods for silicon wafers. A culture of HeLa cancer cells, commonly used in genetic research, has been employed for testing the nanoinjection process. Propidium iodide at several concentrations has been used as the dye for cell injection. The dye binds to nucleic acids after injection, and does not fluoresce when not bound, allowing accurate flow cytometry measurement of successful injections. Over 200 wells were tested to gather reliable testing data, consisting of negative controls (no treatment), positive controls (dye added with no injection), and samples (dye added and injection performed). Tests were performed for dye concentrations of 20, 40, 60, and 80 μL per 1 mL of cell media solution, for two different lance array geometries. The multi-cell nanoinjection process presented in this paper has proven to produce positive dye uptake results in injected cells while maintaining high cell viability, with an average uptake rate of about 52% for cells injected with the highest concentration of dye. Reviewing all data, the average sample success rate is 8 times higher than the rate of dye uptake in the positive controls. Cell viability in these tests is on average 96.2%. The process may be used in a variety of research areas.

This paper introduces a metamorphic erectable cell restraint (MECR) to provide cell restraint in genetic research. A micro-electromechanical systems (MEMS) metamorphic mechanism with two phases of motion was designed to grasp individual embryos about their midplane. The first phase of motion lifts a compliant gripper approximately 40 μm (about half the diameter of an embryo). The gripper then closes in the second phase to grasp the embryo. The metamorphic mechanism includes compliant mechanism components which are analyzed here. A microscale prototype was fabricated from polysilicon and used to demonstrate the mechanism’s two phase motion.

This paper describes a fully compliant constant-force micro-mechanism that enables dual-stage motion for nanoinjection. Nanoinjection is a recently developed process for delivering DNA into mouse zygotes via electrostatic accumulation and release of the DNA onto a microelectromechanical system (MEMS) lance. The fully compliant constant-force nanoinjector is a concatenation of two separate mechanisms: a six-bar mechanism with compliant lamina-emergent torsional (LET) joints to raise the lance, and a pair of constant-force crank-sliders with LET joints positioned on either side of the six-bar mechanism to drive the lance forward. The fully compliant nanoinjector exhibits self-reconfiguring metamorphic motion to first raise the lance to the midline of the zygote and then translate the lance forward with a controlled motion. This dual-stage motion is necessary for the lance to pierce the zygote without causing damage to the cell membrane. The device achieves two sequential displacement behaviors in a compliant mechanism fabricated from a single, continuous piece of material.