A Battery Method to Enhance the Degradation of Iron Stent and Regulating the Effect on Living Cells

A Mg Battery-Integrated Bioelectronic Patch Provides Efficient Electrochemical Stimulations for Wound Healing

Bioelectronic patches hold promise for patient-comfort wound healing providing simplified clinical operation. Currently, they face paramount challenges in establishing long-term effective electronic interfaces with targeted cells and tissues due to the inconsistent energy output and high bio interface impedance. Here a new electrochemical stimulation technology is reported, using a simple wound patch, which integrates the efficient generation and delivery of stimulation. This is realized by employing a hydrogel bioelectronic interface as an active component in an integrated power source (i.e., Mg battery). The Mg battery enhances fibroblast functions (proliferation, migration, and growth factor secretion) and regulates macrophage phenotype (promoting regenerative polarization and down-regulating pro-inflammatory cytokines), by providing an electric field and the ability to control the cellular microenvironment through chemical release. This bioelectronic patch shows an effective and accelerated wound closure by guiding epithelial migration, mediating immune response, and promoting vasculogenesis. This new electrochemical-mediated therapy may provide a new avenue for user-friendly wound management as well as a platform for fundamental insights into cell stimulation.

Remotely Controlled Electrochemical Degradation of Metallic Implants

Biodegradable medical implants promise to benefit patients by eliminating risks and discomfort associated with permanent implantation or surgical removal. The time until full resorption is largely determined by the implant's material composition, geometric design, and surface properties. Implants with a fixed residence time, however, cannot account for the needs of individual patients, thereby imposing limits on personalization. Here, an active Fe-based implant system is reported whose biodegradation is controlled remotely and in situ. This is achieved by incorporating a galvanic cell within the implant. An external and wireless signal is used to activate the on-board electronic circuit that controls the corrosion current between the implant body and an integrated counter electrode. This configuration leads to the accelerated degradation of the implant and allows to harvest electrochemical energy that is naturally released by corrosion. In this study, the electrochemical properties of the Fe-30Mn-1C/Pt galvanic cell model system is first investigated and high-resolution X-ray microcomputed tomography is used to evaluate the galvanic degradation of stent structures. Subsequently, a centimeter-sized active implant prototype is assembled with conventional electronic components and the remotely controlled corrosion is tested in vitro. Furthermore, strategies toward the miniaturization and full biodegradability of this system are presented.

Tissue-Matchable and Implantable Batteries Toward Biomedical Applications

Implantable electronic devices can realize real-time and reliable health monitoring, diagnosis, and treatment of human body, which are expected to overcome important bottlenecks in the biomedical field. However, the commonly used energy supply devices for them are implantable batteries based on conventional rigid device design with toxic components, which both mechanically and biologically mismatch soft biological tissues. Therefore, the development of highly soft, safe, and implantable tissue-matchable flexible batteries is of great significance and urgency for implantable bioelectronics. In this work, the recent advances of tissue-matchable and implantable flexible batteries are overviewed, focusing on the design strategies of electrodes/batteries and their biomedical applications. The mechanical flexibility, biocompatibility, and electrochemical performance in vitro and in vivo of these flexible electrodes/batteries are then discussed. Finally, perspectives are provided on the current challenges and possible directions of this field in the future.

Progress in the preparation of Prussian blue-based nanomaterials for biomedical applications

Prussian blue (PB) is composed of the coordination network of Fe²⁺-CN-Fe³⁺ mixed valence state as a classic metal complex, which includes a C atom and Fe²⁺ (low spin), N atom and Fe³⁺ (high spin). PB and its analogues (PBA) have excellent biosafety, good magnetic properties, outstanding photothermal properties and the ability to mimic enzymatic behaviors due to their stable structure, tunable size, controllable morphology, abundant modification methods and excellent physicochemical properties. They have received increasing research interest and have shown promising applications in the biomedical field. Here, progress in the preparation of PB-based nanomaterials for biomedical applications is summarized and discussed. The preparation strategies, traditional synthesis and emerging preparation methods of PB are summarized systematically in this review. The design and preparation of PBA, PB(PBA)-based hollow structures and PB(PBA)-based composites are also included. While introducing the preparation status, some PB-based nanomaterials that have performed well in specific biomedical fields are emphasized. More importantly, the key factors and future development of PB for the clinical translation as multifunctional nanomaterials are also discussed. This review provides a reference for the design and biomedical application of PB-based nanomaterials.