Stanford Advisors

All Publications

  • Genetically targeted chemical assembly of polymers specifically localized extracellularly to surface membranes of living neurons. Science advances Zhang, A., Loh, K. Y., Kadur, C. S., Michalek, L., Dou, J., Ramakrishnan, C., Bao, Z., Deisseroth, K. 2023; 9 (32): eadi1870


    Multicellular biological systems, particularly living neural networks, exhibit highly complex organization properties that pose difficulties for building cell-specific biocompatible interfaces. We previously developed an approach to genetically program cells to assemble structures that modify electrical properties of neurons in situ, opening up the possibility of building minimally invasive cell-specific structures and interfaces. However, the efficiency and biocompatibility of this approach were challenged by limited membrane targeting of the constructed materials. Here, we design a method for highly localized expression of enzymes targeted to the plasma membrane of primary neurons, with minimal intracellular retention. Next, we show that polymers synthesized in situ by this approach form dense extracellular clusters selectively on the targeted cell membrane and that neurons remain viable after polymerization. Last, we show generalizability of this method across a range of design strategies. This platform can be readily extended to incorporate a broad diversity of materials onto specific cell membranes within tissues and may further enable next-generation biological interfaces.

    View details for DOI 10.1126/sciadv.adi1870

    View details for PubMedID 37556541

  • Environmentally stable and stretchable polymer electronics enabled by surface-tethered nanostructured molecular-level protection. Nature nanotechnology Zheng, Y., Michalek, L., Liu, Q., Wu, Y., Kim, H., Sayavong, P., Yu, W., Zhong, D., Zhao, C., Yu, Z., Chiong, J. A., Gong, H., Ji, X., Liu, D., Zhang, S., Prine, N., Zhang, Z., Wang, W., Tok, J. B., Gu, X., Cui, Y., Kang, J., Bao, Z. 2023


    Stretchable polymer semiconductors (PSCs) are essential for soft stretchable electronics. However, their environmental stability remains a longstanding concern. Here we report a surface-tethered stretchable molecular protecting layer to realize stretchable polymer electronics that are stable in direct contact with physiological fluids, containing water, ions and biofluids. This is achieved through the covalent functionalization of fluoroalkyl chains onto a stretchable PSC film surface to form densely packed nanostructures. The nanostructured fluorinated molecular protection layer (FMPL) improves the PSC operational stability over an extended period of 82 days and maintains its protection under mechanical deformation. We attribute the ability of FMPL to block water absorption and diffusion to its hydrophobicity and high fluorination surface density. The protection effect of the FMPL (~6 nm thickness) outperforms various micrometre-thick stretchable polymer encapsulants, leading to a stable PSC charge carrier mobility of ~1 cm2 V-1 s-1 in harsh environments such as in 85-90%-humidity air for 56 days or in water or artificial sweat for 42 days (as a benchmark, the unprotected PSC mobility degraded to 10-6 cm2 V-1 s-1 in the same period). The FMPL also improved the PSC stability against photo-oxidative degradation in air. Overall, we believe that our surface tethering of the nanostructured FMPL is a promising approach to achieve highly environmentally stable and stretchable polymer electronics.

    View details for DOI 10.1038/s41565-023-01418-y

    View details for PubMedID 37322142

  • Shear-aligned large-area organic semiconductor crystals through extended pi-pi interaction JOURNAL OF MATERIALS CHEMISTRY C Zhang, S., Talnack, F., Jousselin-Oba, T., Bhat, V., Wu, Y., Lei, Y., Tomo, Y., Gong, H., Michalek, L., Zhong, D., Wu, C., Yassar, A., Mannsfeld, S., Risko, C., Frigoli, M., Bao, Z. 2023

    View details for DOI 10.1039/d3tc01311a

    View details for Web of Science ID 001006838400001

  • Autonomous alignment and healing in multilayer soft electronics using immiscible dynamic polymers. Science (New York, N.Y.) Cooper, C. B., Root, S. E., Michalek, L., Wu, S., Lai, J. C., Khatib, M., Oyakhire, S. T., Zhao, R., Qin, J., Bao, Z. 2023; 380 (6648): 935-941


    Self-healing soft electronic and robotic devices can, like human skin, recover autonomously from damage. While current devices use a single type of dynamic polymer for all functional layers to ensure strong interlayer adhesion, this approach requires manual layer alignment. In this study, we used two dynamic polymers, which have immiscible backbones but identical dynamic bonds, to maintain interlayer adhesion while enabling autonomous realignment during healing. These dynamic polymers exhibit a weakly interpenetrating and adhesive interface, whose width is tunable. When multilayered polymer films are misaligned after damage, these structures autonomously realign during healing to minimize interfacial free energy. We fabricated devices with conductive, dielectric, and magnetic particles that functionally heal after damage, enabling thin-film pressure sensors, magnetically assembled soft robots, and underwater circuit assembly.

    View details for DOI 10.1126/science.adh0619

    View details for PubMedID 37262169

  • Effect of Molecular Weight on the Morphology of a Polymer Semiconductor-Thermoplastic Elastomer Blend ADVANCED ELECTRONIC MATERIALS Pena-Alcantara, A., Nikzad, S., Michalek, L., Prine, N., Wang, Y., Gong, H., Ponte, E., Schneider, S., Wu, Y., Root, S. E., He, M., Tok, J., Gu, X., Bao, Z. 2023
  • Realizing Intrinsically Stretchable Semiconducting Polymer Films by Nontoxic Additives ACS MATERIALS LETTERS Cheng, H., Zhang, S., Michalek, L., Ji, X., Luo, S., Cooper, C. B., Gong, H., Nikzad, S., Chiong, J. A., Wu, Y., Zheng, Y., Liu, Q., Zhong, D., Lei, Y., Tomo, Y., Wei, K., Zhou, D., Tok, J., Bao, Z. 2022; 4 (11): 2328-2336
  • Photostationary State in Dynamic Covalent Networks ACS MACRO LETTERS Chambers, L. C., Barner-Kowollik, C., Barner, L., Michalek, L., Frisch, H. 2022; 11 (4): 532-536


    We explore a cross-linked polymer network based on a visible light photodynamic [2 + 2] cycloaddition driven by styrylpyrene chemistry. Based on a polymer backbone with pendent styrylpyrene units, the network can be formed by using λ = 450 nm irradiation. Upon irradiation with λ = 340 nm, a photostationary state is generated within the network with ∼17% of the styrylpyrene units open compared to close to 2% in the visible light cured state. The limited fraction of open [2 + 2] couples is caused by their proximity and is in sharp contrast to solution experiments on the photoreactive moiety. Thus, the polymer network retains its mechanical properties even at the photostationary point. We hypothesize that the application of an additional stimulus could serve as a second gate for inducing network disintegration by spacing the [2 + 2] units during ultraviolet irradiation.

    View details for DOI 10.1021/acsmacrolett.2c00097

    View details for Web of Science ID 000790005700019

    View details for PubMedID 35575324

  • A versatile and straightforward process to turn plastics into antibacterial materials POLYMER CHEMISTRY Hadiouch, S., Maresca, M., Gigmes, D., Machado, G., Maurel-Pantel, A., Frik, S., Saunier, J., Deniset-Besseau, A., Yagoubi, N., Michalek, L., Barner-Kowollik, C., Guillaneuf, Y., Lefay, C. 2021; 13 (1): 69-79

    View details for DOI 10.1039/d1py01344k

    View details for Web of Science ID 000724952500001

  • A Versatile Light-Triggered Radical-Releasing Surface Coating Technology ADVANCED MATERIALS TECHNOLOGIES Boase, N. B., Michalek, L., Hooker, J. P., Fairfull-Smith, K. E. 2022; 7 (4)
  • Light-Gated Control of Conformational Changes in Polymer Brushes ADVANCED MATERIALS TECHNOLOGIES Bialas, S., Krappitz, T., Walden, S. L., Kalayci, K., Kodura, D., Frisch, H., MacLeod, J. M., Nelson, A., Michalek, L., Barner-Kowollik, C. 2022; 7 (4)