A Novel Magnetic Actuation Scheme to Disaggregate Nanoparticles and Enhance Passage across the Blood–Brain Barrier

The blood–brain barrier (BBB) hinders drug delivery to the brain. Despite various efforts to develop preprogramed actuation schemes for magnetic drug delivery, the unmodeled aggregation phenomenon limits drug delivery performance. This paper proposes a novel scheme with an aggregation model for a feed-forward magnetic actuation design. A simulation platform for aggregated particle delivery is developed and an actuation scheme is proposed to deliver aggregated magnetic nanoparticles (MNPs) using a discontinuous asymmetrical magnetic actuation. The experimental results with a Y-shaped channel indicated the success of the proposed scheme in steering and disaggregation. The delivery performance of the developed scheme was examined using a realistic, three-dimensional (3D) vessel simulation. Furthermore, the proposed scheme enhanced the transport and uptake of MNPs across the BBB in mice. The scheme presented here facilitates the passage of particles across the BBB to the brain using an electromagnetic actuation scheme

Electronically integrated microcatheters based on self-assembling polymer films

Existing electronically integrated catheters rely on the manual assembly of separate components to integrate sensing and actuation capabilities. This strongly impedes their miniaturization and further integration. Here, we report an electronically integrated self-assembled microcatheter. Electronic components for sensing and actuation are embedded into the catheter wall through the self-assembly of photolithographically processed polymer thin films. With a diameter of only about 0.1 mm, the catheter integrates actuated digits for manipulation and a magnetic sensor for navigation and is capable of targeted delivery of liquids. Fundamental functionalities are demonstrated and evaluated with artificial model environments and ex vivo tissue. Using the integrated magnetic sensor, we develop a strategy for the magnetic tracking of medical tools that facilitates basic navigation with a high resolution below 0.1 mm. These highly flexible and microsized integrated catheters might expand the boundary of minimally invasive surgery and lead to new biomedical applications. Copyright © 2021 The Authors, some rights reserved

MEMS Technology for Biomedical Imaging Applications

Biomedical imaging is the key technique and process to create informative images of the human body or other organic structures for clinical purposes or medical science. Micro-electro-mechanical systems (MEMS) technology has demonstrated enormous potential in biomedical imaging applications due to its outstanding advantages of, for instance, miniaturization, high speed, higher resolution, and convenience of batch fabrication. There are many advancements and breakthroughs developing in the academic community, and there are a few challenges raised accordingly upon the designs, structures, fabrication, integration, and applications of MEMS for all kinds of biomedical imaging. This Special Issue aims to collate and showcase research papers, short commutations, perspectives, and insightful review articles from esteemed colleagues that demonstrate: (1) original works on the topic of MEMS components or devices based on various kinds of mechanisms for biomedical imaging; and (2) new developments and potentials of applying MEMS technology of any kind in biomedical imaging. The objective of this special session is to provide insightful information regarding the technological advancements for the researchers in the community

Biomedical Applications of Protein Films and Polymeric Nanomaterials

Biomaterials are widely applied for the diagnosis and treatment of numerous diseases. In addition to fulfilling specific biological functions, biomaterials must also be non-toxic, biocompatible, and sterilizable to be regarded as safe-for-use. Polymers are excellent candidates for fabricating functional biomaterials due to their wide availability and varied properties and may be natural or synthetic. Polymer precursors are fabricated into coatings, foams, scaffolds, gels, composites, and nanomaterials for several biomedical applications. This dissertation focuses on two types of polymeric biomaterials – protein-based materials and synthetic polymeric nanoparticles. Proteins are biopolymers that naturally occur with a variety of structural and functional properties. However, the fabrication of protein-based materials is challenging due to their aqueous and mechanical instability. In this work we highlighted the development of an additive-free, thermal treatment approach that relies on heat-curing protein films in fluorous media (fluorous-curing). In doing so, we are able to minimize protein denaturation and retain surface properties. Charged protein films were utilized to prepare antimicrobial coatings and size-sorting devices. We also demonstrated the utility of fluorous-curing to enhance mechanical and enzymatic stability of collagen films with minimal denaturation. In the latter part of this work, we utilized ultrasound treatment to enhance the activity of biomaterials. Ultrasound is gaining interest as a tool used in combination with biomaterials for applications such as enhanced penetration of therapeutics into tissue, regulating drug release through ultrasound-responsive scaffolds, and sonodynamic therapy. However, these developments are limited and delayed due to the lack of effective in vitro models that prevent uncontrolled cell lysis during ultrasound. We developed 2D and 3D cell cultures for ultrasound treatment using collagen-based materials. We hypothesized that collagen would act as a support for the cells and absorb the energy exerted by ultrasound, thereby protecting the cells. We then utilized ultrasound in combination with antimicrobial polymeric nanomaterials for the synergistic eradication of bacterial biofilms. Antimicrobial polymer nanoparticles are an alternative to traditional antibiotics that prevent development of drug resistance. However, longer incubation durations and higher concentrations are required to allow for penetration into the bacterial biofilms which results in toxicity to mammalian cells. Ultrasound enhances the penetration of these nanoparticles into the biofilm EPS thereby reducing the incubation time and enhancing antimicrobial activity, with minimal toxicity to mammalian cells. Overall, this dissertation discusses significant developments in polymeric materials for varied potential applications as diagnostic sensors, antimicrobial materials, wound-healing, tissue engineering, and drug delivery applications