All Publications

  • On-Demand, Reversible, Ultrasensitive Polymer Membrane Based on Molecular Imprinting Polymer. ACS nano Mintz Hemed, N., Leal-Ortiz, S., Zhao, E. T., Melosh, N. A. 2023


    The development of in vivo, longitudinal, real-time monitoring devices is an essential step toward continuous, precision health monitoring. Molecularly imprinted polymers (MIPs) are popular sensor capture agents that are more robust than antibodies and have been used for sensors, drug delivery, affinity separations, assays, and solid-phase extraction. However, MIP sensors are typically limited to one-time use due to their high binding affinity (>107 M-1) and slow-release kinetics (<10-4 muM/sec). To overcome this challenge, current research has focused on stimuli-responsive MIPs (SR-MIPs), which undergo a conformational change induced by external stimuli to reverse molecular binding, requiring additional chemicals or outside stimuli. Here, we demonstrate fully reversible MIP sensors based on electrostatic repulsion. Once the target analyte is bound within a thin film MIP on an electrode, a small electrical potential successfully releases the bound molecules, enabling repeated, accurate measurements. We demonstrate an electrostatically refreshed dopamine sensor with a 760 pM limit of detection, linear response profile, and accuracy even after 30 sensing-release cycles. These sensors could repeatedly detect <1 nM dopamine released from PC-12 cells in vitro, demonstrating they can longitudinally measure low concentrations in complex biological environments without clogging. Our work provides a simple and effective strategy for enhancing the use of MIPs-based biosensors for all charged molecules in continuous, real-time health monitoring and other sensing applications.

    View details for DOI 10.1021/acsnano.2c11618

    View details for PubMedID 36913954

  • Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing. Nature biotechnology Jiang, Y., Trotsyuk, A. A., Niu, S., Henn, D., Chen, K., Shih, C. C., Larson, M. R., Mermin-Bunnell, A. M., Mittal, S., Lai, J. C., Saberi, A., Beard, E., Jing, S., Zhong, D., Steele, S. R., Sun, K., Jain, T., Zhao, E., Neimeth, C. R., Viana, W. G., Tang, J., Sivaraj, D., Padmanabhan, J., Rodrigues, M., Perrault, D. P., Chattopadhyay, A., Maan, Z. N., Leeolou, M. C., Bonham, C. A., Kwon, S. H., Kussie, H. C., Fischer, K. S., Gurusankar, G., Liang, K., Zhang, K., Nag, R., Snyder, M. P., Januszyk, M., Gurtner, G. C., Bao, Z. 2022


    'Smart' bandages based on multimodal wearable devices could enable real-time physiological monitoring and active intervention to promote healing of chronic wounds. However, there has been limited development in incorporation of both sensors and stimulators for the current smart bandage technologies. Additionally, while adhesive electrodes are essential for robust signal transduction, detachment of existing adhesive dressings can lead to secondary damage to delicate wound tissues without switchable adhesion. Here we overcome these issues by developing a flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with skin-interfacing hydrogel electrodes capable of on-demand adhesion and detachment. In mice, we demonstrate that our wound care system can continuously monitor skin impedance and temperature and deliver electrical stimulation in response to the wound environment. Across preclinical wound models, the treatment group healed ~25% more rapidly and with ~50% enhancement in dermal remodeling compared with control. Further, we observed activation of proregenerative genes in monocyte and macrophage cell populations, which may enhance tissue regeneration, neovascularization and dermal recovery.

    View details for DOI 10.1038/s41587-022-01528-3

    View details for PubMedID 36424488

    View details for PubMedCentralID 5350204

  • Ag-Diamond Core-Shell Nanostructures Incorporated with Silicon-Vacancy Centers. ACS materials Au Li, S., Francaviglia, L., Kohler, D. D., Jones, Z. R., Zhao, E. T., Ogletree, D. F., Weber-Bargioni, A., Melosh, N. A., Hamers, R. J. 2022; 2 (2): 85-93


    Silicon-vacancy (SiV) centers in diamond have attracted attention as highly stable fluorophores for sensing and as possible candidates for quantum information science. While prior studies have shown that the formation of hybrid diamond-metal structures can increase the rates of optical absorption and emission, many practical applications require diamond plasmonic structures that are stable in harsh chemical and thermal environments. Here, we demonstrate that Ag nanospheres, produced both in quasi-random arrays by thermal dewetting and in ordered arrays using electron-beam lithography, can be completely encapsulated with a thin diamond coating containing SiV centers, leading to hybrid core-shell nanostructures exhibiting extraordinary chemical and thermal stability as well as enhanced optical properties. Diamond shells with a thickness on the order of 20-100 nm are sufficient to encapsulate and protect the Ag nanostructures with different sizes ranging from 20 nm to hundreds of nanometers, allowing them to withstand heating to temperatures of 1000 °C and immersion in harsh boiling acid for 24 h. Ultrafast photoluminescence lifetime and super-resolution optical imaging experiments were used to study the SiV properties on and off the core-shell structures, which show that the SiV on core-shell structures have higher brightness and faster decay rate. The stability and optical properties of the hybrid Ag-diamond core-shell structures make them attractive candidates for high-efficiency imaging and quantum-based sensing applications.

    View details for DOI 10.1021/acsmaterialsau.1c00027

    View details for PubMedID 36855764

    View details for PubMedCentralID PMC9888652