Ultra-low frequency magnetic energy focusing for highly effective wireless powering of deep-tissue implantable electronic devices.

The limited lifespan of batteries is a challenge in the application of implantable electronic devices. Existing wireless power technologies such as ultrasound, near-infrared light and magnetic fields cannot charge devices implanted in deep tissues, resulting in energy attenuation through tissues and thermal generation. Herein, an ultra-low frequency magnetic energy focusing (ULFMEF) methodology was developed for the highly effective wireless powering of deep-tissue implantable devices. A portable transmitter was used to output the low-frequency magnetic field (<50 Hz), which remotely drives the synchronous rotation of a magnetic core integrated within the pellet-like implantable device, generating an internal rotating magnetic field to induce wireless electricity on the coupled coils of the device. The ULFMEF can achieve energy transfer across thick tissues (up to 20 cm) with excellent transferred power (4-15 mW) and non-heat effects in tissues, which is remarkably superior to existing wireless powering technologies. The ULFMEF is demonstrated to wirelessly power implantable micro-LED devices for optogenetic neuromodulation, and wirelessly charged an implantable battery for programmable electrical stimulation on the sciatic nerve. It also bypassed thick and tough protective shells to power the implanted devices. The ULFMEF thus offers a highly advanced methodology for the generation of wireless powered biodevices.

Coupling of nanostraws with diverse physicochemical perforation strategies for intracellular DNA delivery.

Effective intracellular DNA transfection is imperative for cell-based therapy and gene therapy. Conventional gene transfection methods, including biochemical carriers, physical electroporation and microinjection, face challenges such as cell type dependency, low efficiency, safety concerns, and technical complexity. Nanoneedle arrays have emerged as a promising avenue for improving cellular nucleic acid delivery through direct penetration of the cell membrane, bypassing endocytosis and endosome escape processes. Nanostraws (NS), characterized by their hollow tubular structure, offer the advantage of flexible solution delivery compared to solid nanoneedles. However, NS struggle to stably self-penetrate the cell membrane, resulting in limited delivery efficiency. Coupling with extra physiochemical perforation strategies is a viable approach to improve their performance. This study systematically compared the efficiency of NS coupled with polyethylenimine (PEI) chemical modification, mechanical force, photothermal effect, and electric field on cell membrane perforation and DNA transfection. The results indicate that coupling NS with PEI modification, mechanical force, photothermal effects provide limited enhancement effects. In contrast, NS-electric field coupling significantly improves intracellular DNA transfection efficiency. This work demonstrates that NS serve as a versatile platform capable of integrating various physicochemical strategies, while electric field coupling stands out as a form worthy of primary consideration for efficient DNA transfection.

Technological Advances of Wearable Device for Continuous Monitoring of In Vivo Glucose.

Managing diabetes is a chronic challenge today, requiring monitoring and timely insulin injections to maintain stable blood glucose levels. Traditional clinical testing relies on fingertip or venous blood collection, which has facilitated the emergence of continuous glucose monitoring (CGM) technology to address data limitations. Continuous glucose monitoring technology is recognized for tracking long-term blood glucose fluctuations, and its development, particularly in wearable devices, has given rise to compact and portable continuous glucose monitoring devices, which facilitates the measurement of blood glucose and adjustment of medication. This review introduces the development of wearable CGM-based technologies, including noninvasive methods using body fluids and invasive methods using implantable electrodes. The advantages and disadvantages of these approaches are discussed as well as the use of microneedle arrays in minimally invasive CGM. Microneedle arrays allow for painless transdermal puncture and are expected to facilitate the development of wearable CGM devices. Finally, we discuss the challenges and opportunities and look forward to the biomedical applications and future directions of wearable CGM-based technologies in biological research.

Integrated electronic/fluidic microneedle system for glucose sensing and insulin delivery.

Background: Precise and dynamic blood glucose regulation is paramount for both diagnosing and managing diabetes. Continuous glucose monitoring (CGM) coupled with insulin pumps forms an artificial pancreas, enabling closed-loop control of blood glucose levels. Indeed, this integration necessitates advanced micro-nano fabrication techniques to miniaturize and combine sensing and delivery modules on a single electrode. While microneedle technology can mitigate discomfort, concerns remain regarding infection risk and potential sensitivity limitations due to their short needle length. Methods: This study presents the development of an integrated electronic/fluidic microneedle patch (IEFMN) designed for both glucose sensing and insulin delivery. The use of minimally invasive microneedles mitigates nerve contact and reduces infection risks. The incorporation of wired enzymes addresses the issue of "oxygen deprivation" during glucose detection by decreasing the reliance on oxygen. The glucose-sensing electrodes employ wired enzyme functionalization to achieve lower operating voltages and enhanced resilience to sensor interference. The hollow microneedles' inner channel facilitates precise drug delivery for blood glucose regulation. Results: Our IEFMN-based system demonstrated high sensitivity, selectivity, and a wide response range in glucose detection at relatively low voltages. This effectively reduced interference from both external and internal active substances. The microneedle array ensured painless and minimally invasive skin penetration, while wired enzyme functionalization not only lowered sensing potential but also improved glucose detection accuracy. In vivo, experiments conducted in rats showed that the device could track subcutaneous glucose fluctuations in real-time and deliver insulin to regulate blood glucose levels. Conclusions: Our work suggests that the IEFMN-based system, developed for glucose sensing and insulin delivery, exhibits good performance during in vivo glucose detection and drug delivery. It holds the potential to contribute to real-time, intelligent, and controllable diabetes management.

Personalized Machine Learning-Coupled Nanopillar Triboelectric Pulse Sensor for Cuffless Blood Pressure Continuous Monitoring.

A wearable system that can continuously track the fluctuation of blood pressure (BP) based on pulse signals is highly desirable for the treatments of cardiovascular diseases, yet the sensitivity, reliability, and accuracy remain challenging. Since the correlations of pulse waveforms to BP are highly individualized due to the diversity of the patients' physiological characteristics, wearable sensors based on universal designs and algorithms often fail to derive BP accurately when applied on individual patients. Herein, a wearable triboelectric pulse sensor based on a biomimetic nanopillar layer was developed and coupled with Personalized Machine Learning (ML) to provide accurate and continuous monitoring of BP. Flexible conductive nanopillars as the triboelectric layer were fabricated through soft lithography replication of a cicada wing, which could effectively enhance the sensor's output performance to detect weak signal characteristics of pulse waveform for BP derivation. The sensors were coupled with a personalized Partial Least-Squares Regression (PLSR) ML to derive unknown BP based on individual pulse characteristics with reasonable accuracy, avoiding the issue of individual variability that was encountered by General PLSR ML or formula algorithms. The cuffless and intelligent design endow this ML-sensor as a highly promising platform for the care and treatments of hypertensive patients.

Nanochannel Electro-Injection as a Versatile Platform for Efficient RNA/DNA Programming on Dendritic Cells.

The utilization of dendritic cell (DC) vaccines is a promising approach in cancer immunotherapy, and the modification of DCs for the expression of tumor-associated antigens is critical for successful cancer immunotherapy. A safe and efficient method for delivering DNA/RNA into DCs without inducing maturation is beneficial to achieve successful DC transformation for cell vaccine applications, yet remains challenging. This work presents a nanochannel electro-injection (NEI) system for the safe and efficient delivery of a variety of nucleic acid molecules into DCs. The device is based on track-etched nanochannel membrane as key components, where the nano-sized channels localize the electric field on the cell membrane, enabling lower voltage (<30 V) for cell electroporation. The pulse conditions of NEI are examined so that the transfection efficiency (>70%) and biosafety (viability >85%) on delivering fluorescent dyes, plasmid DNA, messenger RNA, and circular RNA (circRNA) into DC2.4 are optimized. Primary mouse bone marrow DC can also be transfected with circRNA with 68.3% efficiency, but without remarkably affecting cellular viability or inducing DC maturation. These results suggest that NEI can be a safe and efficient transfection platform for in vitro transformation of DCs and possesses a promising potential for developing DC vaccines against cancer.

A 3D-printed microneedle extraction system integrated with patterned electrodes for minimally invasive transdermal detection.

Point-of-Care-Testing (POCT) is a convenient and timely clinical analysis method, leading the development trend of advanced biosensors. The development of POCT equipment that can achieve minimally invasive percutaneous monitoring can avoid the pain felt by the subjects and achieve in vivo and efficient measurement. Here, we reported the development of a microneedle (MN) extraction system based on patterned electrodes, which could provide convenient and minimally invasive detection of bio-analytes (including glucose, pH, and H2O2). The 3D-printed hollow MN array was used as a painless transdermal tool, while the interstitial fluid was extracted under negative-pressure conditions. The patterned electrodes could improve the electrochemical performance of the sensor, with the synergistic effect of the micropillar structure to increase the enzyme coating surface area and the nanomaterial electron layer. The patterned electrodes were placed on the back of the MN arrays for electrochemical detection. In vitro and in vivo studies showed that the MN-extraction system could detect the corresponding bio-analytes in a minimally invasive manner and it did not cause significant tissue damage. The system developed in this work will provide promising technology to expand the application of POCT for minimal tests on interstitial fluids.

3D-assembled microneedle ion sensor-based wearable system for the transdermal monitoring of physiological ion fluctuations.

Monitoring human health is of considerable significance in biomedicine. In particular, the ion concentrations in blood are important reference indicators related to many diseases. Microneedle array-based sensors have enabled promising breakthroughs in continuous health monitoring due to their minimally invasive nature. In this study, we developed a microneedle sensing-array integrated system to continuously detect subcutaneous ions to monitor human health status in real time based on a fabrication strategy for assembling planar microneedle sheets to form 3D microneedle arrays. The limitations of preparing 3D microneedle structures with multiple electrode channels were addressed by assembling planar microneedle sheets fabricated via laser micromachining; the challenges of modifying closely spaced microneedle tips into different functionalized types of electrodes were avoided. The microneedle sensing system was sufficiently sensitive for detecting real-time changes in Ca2+, K+, and Na+ concentrations, and it exhibited good detection performance. The in vivo results showed that the ion-sensing microneedle array successfully monitored the fluctuations in Ca2+, K+, and Na+ in the interstitial fluids of rats in real time. By using an integrated circuit design, we constructed the proposed microneedle sensor into a wearable integrated monitoring system. The integrated system could potentially provide information feedback for diseases related to physiological ion changes.

Capacitive-piezoresistive hybrid flexible pressure sensor based on conductive micropillar arrays with high sensitivity over a wide dynamic range.

Flexible pressure sensors are the foundation of wearable/implantable biosensing and human-machine interfaces, and mainly comprise piezoresistive-, capacitive-, piezoelectric-, and triboelectric-type sensors. As each type of sensor exhibits different electro-mechanical behaviors, it is challenging to detect various physiological mechanical signals that cover a large pressure range using a given sensor configuration, or even a single type of sensor. Here, we report a capacitive-piezoresistive hybrid flexible pressure sensor based on face-to-face-mounted conductive micropillar arrays as a solution to this challenge. The sensor exhibited high sensitivity over a wide dynamic range of five orders of magnitude, which covers almost the full range of physiological mechanical signals. A process for fabricating large-scale and morphologically homogeneous conductive micropillar arrays was first developed and refined. This track-etched-membrane-based process provides a facile, cost-effective, and highly flexible way to precisely adjust the morphology, modulus, and conductivity of the micropillars according to the application requirements. Subsequently, conductive-micropillar-array-based pressure sensors (MAPS) were developed and optimized to attain all-round sensing performance. The pillar contact behaviors generated significant variations in both the capacitance and resistance of the MAPS in the low-pressure regime (10-4-0.2 kPa), providing high sensitivity in both the capacitive and piezoresistive working modes. The vertical contact, bending and thickening of the pillars under medium pressure (0.2-16 kPa) led to a continuous linear response in both modes. Configuration and optimization enabled the MAPS to detect acoustic pressure (<1 Pa), milligram weights, soft touch (<1 kPa), arterial pulses (1-16 kPa preload), joint motions and plantar pressure (∼100 kPa), and the hybrid sensing mode allowed the MAPS to work in a desirable way. In this work, the piezoresistive mode was mainly employed for a higher accuracy and sampling rate, and can apparently simplify IC design for wearable applications. The circuit converts the resistive variations into electrical signals via the voltage division method and directly reads out the signals after further amplification, filtering and transmission. The improved facile and highly adjustable fabrication process, as well as the flexible hybrid sensing strategy, will benefit the unified design, batch production, quantifiable optimization, and functional diversity of wearable/implantable bioelectronics.

Masticatory system-inspired microneedle theranostic platform for intelligent and precise diabetic management.

Integrated systems for diabetic theranostics present advanced technology to regulate diabetes yet still have critical challenges in terms of accuracy, long-term monitoring, and minimal invasiveness. Inspired by the feature and functions of animal masticatory system, we presented a biomimetic microneedle theranostic platform (MNTP) for intelligent and precise management of diabetes. The MNTP was supported by a miniatured circuit, which used microneedle arrays for on-demand skin penetration, enabling interstitial fluid exudation for simultaneous detection of glucose and physiological ions, and subcutaneous insulin delivery. Interstitial fluid exudation enabled sensing in oxygen-rich environment via the incorporated epidermal sensor functionalized with hybrid carbon nanomaterials. This feature addressed the biosafety issues due to implanted electrodes and the "oxygen-deficit" issues in vivo. The MNTP was demonstrated to accurately detect glucose and ions and deliver insulin to regulate hyperglycemia. The biomimetic and intelligent features of the MNTP endowed it as a highly advanced system for diabetes therapy.

Determination of Transdermal Rate of Metallic Microneedle Array through an Impedance Measurements-Based Numerical Check Screening Algorithm.

Microneedle systems have been widely used in health monitoring, painless drug delivery, and medical cosmetology. Although many studies on microneedle materials, structures, and applications have been conducted, the applications of microneedles often suffered from issues of inconsistent penetration rates due to the complication of skin-microneedle interface. In this study, we demonstrated a methodology of determination of transdermal rate of metallic microneedle array through impedance measurements-based numerical check screening algorithm. Metallic sheet microneedle array sensors with different sizes were fabricated to evaluate different transdermal rates. In vitro sensing of hydrogen peroxide confirmed the effect of transdermal rate on the sensing outcomes. An FEM simulation model of a microneedle array revealed the monotonous relation between the transdermal state and test current. Accordingly, two methods were primely derived to calculate the transdermal rate from the test current. First, an exact logic method provided the number of unpenetrated tips per sheet, but it required more rigorous testing results. Second, a fuzzy logic method provided an approximate transdermal rate on adjacent areas, being more applicable and robust to errors. Real-time transdermal rate estimation may be essential for improving the performance of microneedle systems, and this study provides various fundaments toward that goal.

Semi-Implantable Bioelectronics.

Developing techniques to effectively and real-time monitor and regulate the interior environment of biological objects is significantly important for many biomedical engineering and scientific applications, including drug delivery, electrophysiological recording and regulation of intracellular activities. Semi-implantable bioelectronics is currently a hot spot in biomedical engineering research area, because it not only meets the increasing technical demands for precise detection or regulation of biological activities, but also provides a desirable platform for externally incorporating complex functionalities and electronic integration. Although there is less definition and summary to distinguish it from the well-reviewed non-invasive bioelectronics and fully implantable bioelectronics, semi-implantable bioelectronics have emerged as highly unique technology to boost the development of biochips and smart wearable device. Here, we reviewed the recent progress in this field and raised the concept of "Semi-implantable bioelectronics", summarizing the principle and strategies of semi-implantable device for cell applications and in vivo applications, discussing the typical methodologies to access to intracellular environment or in vivo environment, biosafety aspects and typical applications. This review is meaningful for understanding in-depth the design principles, materials fabrication techniques, device integration processes, cell/tissue penetration methodologies, biosafety aspects, and applications strategies that are essential to the development of future minimally invasive bioelectronics.

A Fully Integrated Closed-Loop System Based on Mesoporous Microneedles-Iontophoresis for Diabetes Treatment.

A closed-loop system that can mini-invasively track blood glucose and intelligently treat diabetes is in great demand for modern medicine, yet it remains challenging to realize. Microneedles technologies have recently emerged as powerful tools for transdermal applications with inherent painlessness and biosafety. In this work, for the first time to the authors' knowledge, a fully integrated wearable closed-loop system (IWCS) based on mini-invasive microneedle platform is developed for in situ diabetic sensing and treatment. The IWCS consists of three connected modules: 1) a mesoporous microneedle-reverse iontophoretic glucose sensor; 2) a flexible printed circuit board as integrated and control; and 3) a microneedle-iontophoretic insulin delivery component. As the key component, mesoporous microneedles enable the painless penetration of stratum corneum, implementing subcutaneous substance exchange. The coupling with iontophoresis significantly enhances glucose extraction and insulin delivery and enables electrical control. This IWCS is demonstrated to accurately monitor glucose fluctuations, and responsively deliver insulin to regulate hyperglycemia in diabetic rat model. The painless microneedles and wearable design endows this IWCS as a highly promising platform to improve the therapies of diabetic patients.

Wearable and Implantable Intraocular Pressure Biosensors: Recent Progress and Future Prospects.

Biosensors worn on or implanted in eyes have been garnering substantial attention since being proven to be an effective means to acquire critical biomarkers for monitoring the states of ophthalmic disease, diabetes. Among these disorders, glaucoma, the second leading cause of blindness globally, usually results in irreversible blindness. Continuous intraocular pressure (IOP) monitoring is considered as an effective measure, which provides a comprehensive view of IOP changes that is beyond reach for the "snapshots" measurements by clinical tonometry. However, to satisfy the applications in ophthalmology, the development of IOP sensors are required to be prepared with biocompatible, miniature, transparent, wireless and battery-free features, which are still challenging with many current fabrication processes. In this work, the recent advances in this field are reviewed by categorizing these devices into wearable and implantable IOP sensors. The materials and structures exploited for engineering these IOP devices are presented. Additionally, their working principle, performance, and the potential risk that materials and device architectures may pose to ocular tissue are discussed. This review should be valuable for preferable structure design, device fabrication, performance optimization, and reducing potential risk of these devices. It is significant for the development of future practical IOP sensors.

Liquid-like Polymer Coating as a Promising Candidate for Reducing Electrode Contamination and Noise in Complex Biofluids.

Biosensors that can automatically and continuously track fluctuations in biomarker levels over time are essential for real-time sensing in biomedical and environmental applications. Although many electrochemical sensors have been developed to quickly and sensitively monitor biomarkers, their sensing stability in complex biofluids is disturbed by unavoidable nonspecific adhesion of proteins or bacteria. Recently, various substrate surface modification techniques have been developed to resist biofouling, yet functionalization of electrodes in sensors to be anti-biofouling is rarely achieved. Here, we report an integrated three-electrode system (ITES) modified with a "liquid-like" polydimethylsiloxane (PDMS) brush that can continuously and stably monitor reactive oxygen species (ROS) in complex fluids. Based on the slippery "liquid-like" coating, the modified ITES surface could prevent the adhesion of various liquids as well as the adhesion of proteins and bacteria. The "liquid-like" coating does not significantly affect the sensitivity of the electrode in detecting ROS, while the sensing performance could remain stable and free of bacterial attack even after 3 days of incubation with bacteria. In addition, the PDMS brush-modified ITES (PMITES) could continuously record ROS levels in bacterial-rich fluids with excellent stability over 24 h due to the reduced bacterial contamination on the electrode surface. This technique offers new opportunities for continuous and real-time monitoring of biomarkers that will facilitate the development of advanced sensors for biomedical and environmental applications.

Liquid-like polymer-based self-cleaning coating for effective prevention of liquid foods contaminations.

Liquid food containers commonly suffer from inevitable contamination and even biofilm formation due to the adhesion of food residuals or saliva, which requires detergents to clean. Although previously reported superhydrophobic and omniphobic coatings can resist the adhesion of liquids, the requirements of specific nanostructures or infused lubricants limit their applications in food containers. Here, by grafting smooth glass containers with "liquid like" polydimethylsiloxane brushes, we developed a unique approach for preparing a slippery coating that could exhibit highly robust repellency to various liquid foods. The coating was highly transparent and did not induce a significant alteration of the smooth surface. The "liquid like" coating could effectively prevent the adhesion of various liquid foods and inhibit the formation of bacterial biofilms, without the use of detergents for cleaning. Moreover, this coating could resist mechanical damage from friction, and displayed high biocompatibility with biological cells. The slipperiness, smoothness, robustness and biocompatibility of the "liquid like" coating was highly beneficial to practical applications as self-cleaning glass container, which has been challenging to achieve by conventional superhydrophobic or omniphobic coatings. Our study introduced a versatile strategy to functionalize biocompatible surfaces for food containers which reduced the contamination of residues and the use of detergents, and may be beneficial to human and environmental health.

Microneedles loaded with anti-PD-1-cisplatin nanoparticles for synergistic cancer immuno-chemotherapy.

Programmed cell death protein-1 (PD-1) on T-cells combined with programmed cell death ligand-1 (PD-L1) critically accounts for tumor immune evasion. Anti-PD-1 (aPD-1) blocks the binding of PD-1 to PD-L1, thus allowing T-cell activation for tumor cell eradication. Currently, the major challenges for cancer immunotherapy are how to improve the response rate and overcome drug resistance. Dermal administration turns out to be a promising route for immunotherapy since skin is a highly active immune organ containing a large population of resident antigen-presenting cells. Microneedle arrays can pierce the immune-cell-rich epidermis, leading to a robust T-cell response in the microenvironment of tumor cells. Herein, we successfully developed a microneedle patch loaded with pH-responsive tumor-targeted lipid nanoparticles (NPs), which allows local delivery of aPD-1 and cisplatin (CDDP) precisely to cancer tissues for cancer therapy. For in vivo studies, aPD-1/CDDP@NPs delivered through microneedles effectively boosted the immune response, thereby a remarkable effect on tumor regression was realized. Synergistic anticancer mechanisms were therefore activated through robust microneedle-induced T-cell response, blockage of PD-1 in T-cells by aPD-1, and an increase in direct cytotoxicity of CDDP in tumor cells. Strikingly, transdermal delivery using MNs increased the response rate in the animal model unresponsive to aPD-1 systemic therapy. This exhibited promise in the treatment of immunotherapy-unresponsive cancers. Taken together, microneedle-mediated local delivery of nano-encapsulated chemotherapeutic and immunotherapeutic agents at tumor skin sites provides a novel treatment strategy and insights into cancer therapy.

Anomalous dispersion of bioinspired flower-like microparticles for oil/water separation.

Hydrophobic particles have been suffering from aggregation in aqueous media, which limits their applications in oil/water separation. Surfactants have been used to increase the dispersity of the hydrophobic particles in water, but this approach compromises particles' hydrophobicity and oil absorption capabilities. Recently, hierarchical microparticles decorated with nanospikes were found to exhibit long-term anomalous dispersion in liquid medium without adding any surfactants. However, whether this anomalous dispersion phenomenon was applicable to 2D nano-petals decorated microparticles still remains unknown. Here, we developed a ZnO-based flower-like microparticles (FLMPs) whose surfaces were attached with 2D nano-petals, and we examined their anomalous dispersity. Our results showed that both hydrophilic and hydrophobic FLMPs could achieve anomalous dispersity either in water or organic solvents, likely due to reduced interparticle collision by the 2D nano-petals. In addition, the functional hydrophobic FLMPs also possessed a large surface area and superhydrophobic surfaces to efficiently absorb oil spills on water and oil emulsion suspended in water. In contrast, the hydrophobic microbeads (MBs) without nano-petals structure seriously aggregated in water and exhibited reduced oil absorption abilities. Our work demonstrated the new finding of 2D nano-pedal structure-mediated anomalous dispersity, and provided a new method for effective oil/water separation using superhydrophobic particles without surfactants.

Reduced Graphene Oxide Nanohybrid-Assembled Microneedles as Mini-Invasive Electrodes for Real-Time Transdermal Biosensing.

A variety of nanomaterial-based biosensors have been developed to sensitively detect biomolecules in vitro, yet limited success has been achieved in real-time sensing in vivo. The application of microneedles (MN) may offer a solution for painless and minimally-invasive transdermal biosensing. However, integration of nanostructural materials on microneedle surface as transdermal electrodes remains challenging in applications. Here, a transdermal H2 O2 electrochemical biosensor based on MNs integrated with nanohybrid consisting of reduced graphene oxide and Pt nanoparticles (Pt/rGO) is developed. The Pt/rGO significantly improves the detection sensitivity of the MN electrode, while the MNs are utilized as a painless transdermal tool to access the in vivo environment. The Pt/rGO nanostructures are protected by a water-soluble polymer layer to avoid mechanical destruction during the MN skin insertion process. The polymer layer can readily be dissolved by the interstitial fluid and exposes the Pt/rGO on MNs for biosensing in vivo. The applications of the Pt/rGO-integrated MNs for in situ and real-time sensing of H2 O2 in vivo are demonstrated both on pigskin and living mice. This work offers a unique real-time transdermal biosensing system, which is a promising tool for sensing in vivo with high sensitivity but in a minimally-invasive manner.

Magnetic Dynamics of a Neodymium(III) Single-Ion Magnet.

Slow relaxation of magnetization is observed in a neodymium(III) single-ion magnet based on phosphine oxide, which successfully extends our pentagonal bipyramidal family to light lanthanides. Comprehensive magnetic characterizations reveal that the magnetic dynamics follow the power law that corresponds to a Raman process, despite an energy splitting of 207 cm-1 evidenced by the ab initio calculation. Compared with a similar complex, the magnetic dynamics and magneto-structural correlations are clarified, providing deeper insight into the pursuit of promising light lanthanide single-molecule magnets.