Unorthodox mechanical microsystems for drug delivery
Time: Fri 2025-12-19 10.00
Location: Kollegiesalen, Brinellvägen 8, Stockholm
Language: English
Subject area: Electrical Engineering Medical Technology
Doctoral student: Theocharis N. Iordanidis , Mikro- och nanosystemteknik
Opponent: Professor Roger Narayan, North Carolina State University, Raleigh, NC, USA
Supervisor: Professor Niclas Roxhed, Mikro- och nanosystemteknik; Professor Göran Stemme, Mikro- och nanosystemteknik
QC 20251107
Abstract
Microelectromechanical systems (MEMS) offer powerful solutions for drug delivery where biological barriers limit the potential of advanced therapeutics. This thesis demonstrates how unorthodox applications of microfabrication techniques can create novel platforms to overcome drug delivery challenges, enhancing the delivery of potent and fragile biologics.
The first part of this work focuses on implantable systems. An ultrasonically actuated micro-implant is presented, which exploits mechanical resonance not for sensing but for the selective, on demand destruction of reservoir membranes. This enables remotely triggered drug release without onboard power or electronics. Building on this, a miniaturized ultrasonic energy harvester is developed, integrating a high-performance, bulk piezoelectric material (PZT-5H) via a novel low-temperature bonding process, creating a robust power source for future active implants.
The second part explores two-photon polymerization (2PP) to fabricate complex 3D microstructures for non-invasive delivery. First, rolling ultra-miniaturized microneedle spheres (RUMS) are introduced. Unlike traditional flat microneedle patches, these 3D particles are suspended in topical formulations to gently and repeatedly disrupt the skin’s stratum corneum, enabling the effective transdermal delivery of biologics. Second, a micro-swirl nozzle, a design typically found in internal combustion or agricultural applications, has been developed to aerosolize fragile biologics. This geometry generates a fine mist suitable for deep lung deliverythrough a low-shear mechanism, preserving the integrity of sensitive payloads like lipid nanoparticle (LNP)-encapsulated mRNA.
Collectively, this work showcases a versatile approach to biomedical engineering, where the precise control of micro-scale geometry and physics is leveraged to solve persistent challenges in therapeutic delivery.