A Magnetically Driven Biodegradable Microsphere with Mass Production Capability for Subunit Vaccine Delivery and Enhanced Immunotherapy

Subunit vaccines have emerged as a promising strategy in immunotherapy for combating viral infections and cancer. Nevertheless, the clinical application of subunit vaccines is hindered by limitations in antigen delivery efficiency, characterized by rapid clearance and inadequate cellular uptake. Here, a novel subunit vaccine delivery system utilizing ovalbumin@magnetic nanoparticles (OVA@MNPs) encapsulated within biodegradable gelatin methacryloyl (GelMA) microspheres was proposed to enhance the efficacy of antigen delivery. OVA@MNPs-loaded GelMA microspheres, denoted as OMGMs, can be navigated through magnetic fields to deliver subunit vaccines into the lymphatic system efficiently. Moreover, the biodegradable OMGMs enabled the sustained release of subunit vaccines, concentrating OVA around lymph nodes and enhancing the efficacy of induced immune response. OMGMs were produced through a microfluidic droplet generation technique, enabling mass production. In murine models, OMGMs successfully accumulated antigens in lymph nodes abundant in antigen-presenting cells, leading to enhanced cellular and humoral immunity and pronounced antitumor effects with a single booster immunization. In conclusion, these findings highlight the promise of OMGMs as a practical subunit vaccination approach, thus addressing the limitations associated with antigen delivery efficiency and paving the way for advanced immunotherapeutic strategies.

Magnetic field control device for transplantation of corneal endothelial tissue with magnetic filaments

The corneal endothelial transplantation involves the transfer and attachment of a single-layered corneal endothelial tissue to the narrow space between the cornea and iris. Given the high risk of damage to the endothelial tissue and surrounding corneal tissues when using sharp instruments inserted externally to apply force during the process, the development of a device capable of transferring corneal endothelial tissue using a magnetic field became necessary. This study aims to develop a magnetic control device for transferring corneal endothelial tissue with attached magnetic particles to the transplant site, validate its appropriate transfer capabilities, and assess its applicability to corneal endothelial transplantation. For this purpose, a magnetic field-generating manipulation device equipped with four electromagnets controlled by a joystick and microcomputer was developed. Through simulated experiments, the strength of the magnetic field and the attraction force on the tissue were predicted, and the actual magnetic field strength was measured for validation. To measure the magnetic transfer force, experiments were conducted by towing corneal endothelial tissue fixed with 6 mg, 12 mg, and 18 mg plastic weights. Subsequently, the tissue's transfer speed was measured after applying continuous and pulsed magnetic fields. The results confirmed the feasibility of tissue transfer using the magnetic control device, and it was observed that pulsed magnetic fields led to faster transfer speeds and easier control compared to continuous magnetic fields. Exploratory animal experiments using rabbits were conducted to simulate real surgical conditions, confirming the feasibility of corneal endothelial tissue transfer and attachment.

A New Hybrid Stepper Motor, Compliant Piezoelectric Micro-Tweezer for Extended Stroke

The revolutionary economic potential of micro and nanotechnology is already recognized. Micro and nano-scale technologies that use electrical, magnetic, optical, mechanical, and thermal phenomena separately or in combination are either already in the industrial phase or approaching it. The products of micro and nanotechnology are made of small quantities of material but have high functionality and added value. This paper presents such a product: a system with micro-tweezers for biomedical applications-a micromanipulator with optimized constructive characteristics, including optimal centering, consumption, and minimum size, for handling micro-particles and constructive micro components. The advantage of the proposed structure consists mainly in obtaining a large working area combined with a good working resolution due to the double actuation principle: electromagnetic and piezoelectric.

2D Magnetic Manipulation of a Micro-Robot in Glycerin Using Six Pairs of Magnetic Coils

This paper demonstrates the control system of a single magnetic micro-robot driven by combined coils. The combined coils consist of three pairs of Helmholtz coils and three pairs of Maxwell coils. The rotating magnetic field, gradient magnetic field, and combined magnetic field model of the combined coils were analyzed. To make the output magnetic field quickly converge to the reference point without steady-state error, the discrete-time optimal controller was designed based on the auto disturbance rejection technology. We have designed a closed-loop controller based on a position servo. The control system includes the position control and direction control of the micro-robot. To address problems with slow sampling frequency in visual feedback and inability to feed real-time position back to the control system, a Kalman filter algorithm was used to predict the position of the micro-robot in two-dimensional space. Simulations and experiments were carried out based on the proposed structure of combined coils and control scheme. The experimental results demonstrated the uniformity and excellent dynamic performance of the generated magnetic field.

Advanced tools and methods for single-cell surgery

Highly precise micromanipulation tools that can manipulate and interrogate cell organelles and components must be developed to support the rapid development of new cell-based medical therapies, thereby facilitating in-depth understanding of cell dynamics, cell component functions, and disease mechanisms. This paper presents a literature review on micro/nanomanipulation tools and their control methods for single-cell surgery. Micromanipulation methods specifically based on laser, microneedle, and untethered micro/nanotools are presented in detail. The limitations of these techniques are also discussed. The biological significance and clinical applications of single-cell surgery are also addressed in this paper.

Evolving from Laboratory Toys towards Life-Savers: Small-Scale Magnetic Robotic Systems with Medical Imaging Modalities

Small-scale magnetic robots are remotely actuated and controlled by an externally applied magnetic field. These robots have a characteristic size ranging from several millimetres down to a few nanometres. They are often untethered in order to access constrained and hard-to-reach space buried deep in human body. Thus, they promise to bring revolutionary improvement to minimally invasive diagnostics and therapeutics. However, existing research is still mostly limited to scenarios in over-simplified laboratory environment with unrealistic working conditions. Further advancement of this field demands researchers to consider complex unstructured biological workspace. In order to deliver its promised potentials, next-generation small-scale magnetic robotic systems need to address the constraints and meet the demands of real-world clinical tasks. In particular, integrating medical imaging modalities into the robotic systems is a critical step in their evolution from laboratory toys towards potential life-savers. This review discusses the recent efforts made in this direction to push small-scale magnetic robots towards genuine biomedical applications. This review examines the accomplishment achieved so far and sheds light on the open challenges. It is hoped that this review can offer a perspective on how next-generation robotic systems can not only effectively integrate medical imaging methods, but also take full advantage of the imaging equipments to enable additional functionalities.