Secure wireless actuation of an implanted microvalve for drug delivery applications

Abstract

The capability to wirelessly control fluid flow through a microvalve can emerge as an attractive technology enabling various biomedical applications such as remote drug delivery and in vitro diagnostics. Contactless powering of such a microvalve is best addressed by near-field inductive coupling due to its close proximity to the external interrogator. In this paper, we propose the use of the same technique for secure remote interrogation and powering of a human implantable, surface acoustic wave (SAW) correlation-based, passive microvalve. This is carried out by interrogating the microvalve with a Barker sequence-encoded BPSK signal. A numerical and experimental analysis of the biotelemetry link for the microvalve was undertaken in the vicinity of numerical and physical human body phantoms, respectively. To accurately account for the path losses and to address the design optimization, the receiver coil/antenna was solved simultaneously with the transmitter coil/antenna in the presence of a human body simulant using three-dimensional, high frequency electromagnetic FEM modelling. The received relative signal strength was numerically and experimentally derived for a miniature (6 mm × 6 mm × 0.5 mm), square spiral antenna/coil when interrogated by a handheld 8 cm × 5 cm × 0.2 cm square spiral antenna/coil in the near-field. Finally, the experimental results agreed well with the FEM analysis predictions and hence ascertained the applicability of the developed system for secure interrogation and remote powering of the newly proposed microvalve.

Actuation Mechanism of Microvalves: A Review

“…The valve was designed to be driven by the minimum value about electromagnetic (EM) radiation, considering existing EM radiation. Length about the required code was researched to guarantee safe manipulation [122,123,125,126]. Zhang et al reported a novel SAW microvalve consisted of the piezoelectric substrate and an interdigital transducer (27.5 MHz).…”

“…There are lots of advantages in the realization of a SAW microvalve including secure [122], reliable and low power operation [121], small size [123], simplicity in construction [124] and cost effectiveness [125]. Such microvalves have a huge range of applications such as in micro electro-mechanical systems (MEMS), nano electro-mechanical systems (NEMS) [121], biomedical applications, lab-on-chip applications [124], drug delivery [125,126], and so on.…”

Induced-charge electrokinetics in microfluidics: a review on recent advancements

“…Manshadi et al [31] Circular/inside a microchamber/DC 500 96.89% developed for basic fluid flow mechanistic studies [102], in vitro diagnostics [103], and biological sample delivery [104]. Rapid response and ability to be integrated into microfluidic systems are the essential criteria for selecting appropriate microvalves.…”

Additive manufacturing of hydrogel-based materials for next-generation implantable medical devices

“…Second, current methods have limitations in constructing entirely biocompatible medical devices. Microelectromechanical systems (MEMS) devices (2)(3)(4)(5) feature moving parts manufactured with methods developed for silicon and metals [such as thin-film deposition, photolithography, and etching (6)], but silicon-based materials present challenges as implantable devices because of their low biocompatibility (7)(8)(9). This limitation extends to implantable electronic devices that use silicon-based transistor circuits, which further require a reliable power supply via either a toxic battery or electronic interconnects between the interior and exterior of the body.…”