Magnetic Shape Memory Micropump for Submicroliter Intracranial Drug Delivery in Rats

Abstract

Point-of-care diagnostic devices, micrototal analysis (μTAS) systems, lab-on-a-chip development, and biomedical research rely heavily upon microfluidic management and innovative micropump design. Here, we describe the design and prototype deployment of a magnetic shape memory (MSM) micropump capable of submicroliter per minute flow rates. The pump contains no valves or moving parts in the fluid channel and is capable of bidirectional fluid transport. This pump was employed as the mechanism to deliver small intracranial dosages of ketamine and tetrodotoxin (TTX) at 0.33 μl/min during in vivo electrophysiological recordings in anesthetized rats, performing to required specifications

Localized deformation in Ni-Mn-Ga single crystals

“…1 Exhibiting magnetic field induced strains of up to 12%, 2 Ni-Mn-Ga is a promising material for use as the active element in actuating devices. [3][4][5][6][7][8] Ni-Mn-Ga's shape change is accommodated by growth, through twin boundary motion, of martensite variants preferentially aligned with the applied magnetic field. The twinning stress necessary to initiate magnetic field induced twin boundary movement in Ni-Mn-Ga has been shown to be as low as 0.05 MPa.…”

Shape memory materials and 4D printing in pharmaceutics

“…upon application of a radio-controlled electromagnetic field) [45,162,163]. The working principle of such devices potentially offers not only quite high precision drug dosing but also increased safety as the system only responds to an external suitably tuned nonmechanical stimulus [164]. To enhance the system flexibility, additional release controlling mechanisms to be coupled with the shape memory effect were also tested, for instance relying on the application of functional coatings and on the variation of the viscosity of the drug containing formulation when in contact with aqueous fluids at body temperature [163].…”

“…capsules, chips) hosting a more or less complex pumping system and drug-loaded reservoirs, the latter connected to the external environment through holes and valves (e.g. two-way, passive-check or thermoactive valves) [164,165]. In some cases, these DDSs were envisaged so that the removal of the stimulus allowed the interruption of the release.…”

“…In some cases, these DDSs were envisaged so that the removal of the stimulus allowed the interruption of the release. As a consequence, fine tuning of the drug delivered (even up to picometric amounts) and on demand pulsatile-release performance could be achieved, leading to good potential for customization [163,164]. Endoscopic capsules were also proposed, entailing a tracking mechanism to monitor the position of the device in the human body after oral administration and ensure drug release at the right site [165].…”

Design and performance analysis of hydraulic switching valve driven by magnetic shape memory alloy

“…17,18 However, the application of MSMA in hydraulic systems is mainly focused on the feasibility analysis of structure design, the applicability of different mathematical models and control strategies for different types of valves to improve the numerical simulation. [19][20][21] Although valve is designed, analysis on the flow field and dynamic characteristics is carded out by simulation, fabrication of the MSMA valve prototype and the flow characteristics still need further demonstration. It is well known that hydraulic system is intrinsically weak in energy efficiency.…”