Electrochemical modulation enhances the selectivity of peripheral neurostimulation in vivo.

Electrical nerve stimulation serves an expanding list of clinical applications, but it faces persistent challenges in selectively activating bundled nerve fibers. In this study, we investigated electrochemical modulation with an ion-selective membrane (ISM) and whether it, used together with electrical stimulation, may provide an approach for selective control of peripheral nerves. Guided by theoretical transport modeling and direct concentration measurements, we developed an implantable, multimodal ISM cuff capable of simultaneous electrical stimulation and focused Ca2+ depletion.

Rapid and Low Cost Manufacturing of Cuff Electrodes.

For many peripheral neuro-modulation applications, the cuff electrode has become a preferred technology for delivering electrical current into targeted volumes of tissue. While basic cuffs with low spatial selectivity, having longitudinally arranged contacts, can be produced from relatively straightforward processes, the fabrication of more complex electrode configurations typically requires iterative design and clean-room fabrication with skilled technicians. Although facile methods for fabricating cuff electrodes exist, their inconsistent products have limited their adoption for rapid manufacturing.

Shape-shifting structured lattices via multimaterial 4D printing.

Shape-morphing structured materials have the ability to transform a range of applications. However, their design and fabrication remain challenging due to the difficulty of controlling the underlying metric tensor in space and time. Here, we exploit a combination of multiple materials, geometry, and 4-dimensional (4D) printing to create structured heterogeneous lattices that overcome this problem.

Acoustophoretic rapid media exchange and continuous-flow electrotransfection of primary human T cells for applications in automated cellular therapy manufacturing.

Autologous cellular therapies based on modifying T cells to express chimeric antigen receptor genes have been highly successful in treating hematological cancers. Deployment of these therapies is limited by the complexity and costs associated with their manufacturing. Transitioning these processes from virus-based methods for gene delivery to a non-viral method, such as electroporation, has the potential to greatly reduce cost and manufacturing time while increasing safety and efficacy.

Scalable high-throughput acoustophoresis in arrayed plastic microchannels.

Microfluidic acoustophoresis is a label-free technique that isolates a purified product from a complex mixture of cells. This technique is well-studied but thus far has lacked the throughput and device manufacturability needed for many medical and industrial uses. Scale-up of acoustofluidic devices can be more challenging than in other microfluidic systems because the channel walls are integral to the resonant behavior and coupling to neighboring channels can inhibit performance.

Design and Realization of 3D Printed AFM Probes.

Atomic force microscope (AFM) probes and AFM imaging by extension are the product of exceptionally refined silicon micromachining, but are also restricted by the limitations of these fabrication techniques. Here, the nanoscale additive manufacturing technique direct laser writing is explored as a method to print monolithic cantilevered probes for AFM. Not only are 3D printed probes found to function effectively for AFM, but they also confer several advantages, most notably the ability to image in intermittent contact mode with a bandwidth approximately ten times larger than analogous silicon probes.

Purification of Lymphocytes by Acoustic Separation in Plastic Microchannels.

Emerging cell therapies have created new demands for instruments that will increase processing efficiency. Purification of lymphocytes prior to downstream steps of gene transfer currently relies on centrifugal separation, which has drawbacks in output sample purity and process automation. Here, we present an alternative approach to blood cell purification using acoustic forces in plastic microchannels.

Directed assembly-based printing of homogeneous and hybrid nanorods using dielectrophoresis.

Printing nano and microscale three-dimensional (3D) structures using directed assembly of nanoparticles has many potential applications in electronics, photonics and biotechnology. This paper presents a reproducible and scalable 3D dielectrophoresis assembly process for printing homogeneous silica and hybrid silica/gold nanorods from silica and gold nanoparticles. The nanoparticles are assembled into patterned vias under a dielectrophoretic force generated by an alternating current (AC) field, and then completely fused in situ to form nanorods.

Carbon fiber on polyimide ultra-microelectrodes.

Objective: Most preparations for making neural recordings degrade over time and eventually fail due to insertion trauma and reactive tissue response. The magnitudes of these responses are thought to be related to the electrode size (specifically, the cross-sectional area), the relative stiffness of the electrode, and the degree of tissue tolerance for the material. Flexible carbon fiber ultra-microelectrodes have a much smaller cross-section than traditional electrodes and low tissue reactivity, and thus may enable improved longevity of neural recordings in the central and peripheral nervous systems.

Rapid prototyping and parametric optimization of plastic acoustofluidic devices for blood-bacteria separation.

Acoustic manipulation has emerged as a versatile method for microfluidic separation and concentration of particles and cells. Most recent demonstrations of the technology use piezoelectric actuators to excite resonant modes in silicon or glass microchannels. Here, we focus on acoustic manipulation in disposable, plastic microchannels in order to enable a low-cost processing tool for point-of-care diagnostics.

A micro-scale printable nanoclip for electrical stimulation and recording in small nerves.

Objective: The vision of bioelectronic medicine is to treat disease by modulating the signaling of visceral nerves near various end organs. In small animal models, the nerves of interest can have small diameters and limited surgical access. New high-resolution methods for building nerve interfaces are desirable.

Crossover from hydrodynamics to the kinetic regime in confined nanoflows.

We present an experimental study of a confined nanoflow, which is generated by a sphere oscillating in the proximity of a flat solid wall in a simple fluid. Varying the oscillation frequency, the confining length scale, and the fluid mean free path over a broad range provides a detailed map of the flow. We use this experimental map to construct a scaling function, which describes the nanoflow in the entire parameter space, including both the hydrodynamic and the kinetic regimes.

The "low-dose" concept and the paradoxical effects of prolactin on grooming and sexual behavior.

The effects of prolactin on animal behavior include the stimulation of novelty-induced grooming in rats. This effect has been demonstrated in hyperprolactinaemic animals bearing pituitary homografts under the kidney capsule or after intracerebroventricular (i.c.