Zhuxiao Gu

Transient implantable piezoelectric materials are desirable for biosensing, drug delivery, tissue regeneration, and antimicrobial and tumor therapy. For use in the human body, they must show flexibility, biocompatibility, and biodegradability. These requirements are challenging for conventional inorganic piezoelectric oxides and piezoelectric polymers. We discovered high piezoelectricity in a molecular crystal HOCH 2 (CF 2 ) 3 CH 2 OH [2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD)] with a large piezoelectric coefficient d 33 of ~138 picocoulombs per newton and piezoelectric voltage constant g 33 of ~2450 × 10 −3 volt-meters per newton under no poling conditions, which also exhibits good biocompatibility toward biological cells and desirable biodegradation and biosafety in physiological environments. HFPD can be composite with polyvinyl alcohol to form flexible piezoelectric films with a d 33 of 34.3 picocoulombs per newton. Our material demonstrates the ability for molecular crystals to have attractive piezoelectric properties and should be of interest for applications in transient implantable electromechanical devices.

, the past decade has witnessed the renaissance of molecular ferroelectrics as promising complementary materials to commercial inorganic ferroelectrics. Thus, on the 100th anniversary of ferroelectricity, it is an opportune time to look into the future, specifically into how to push the boundaries of material design in molecular ferroelectric systems and finally overcome the hurdles to their commercialization. Herein, we present a comprehensive and accessible review of the appealing development of molecular ferroelectrics over the past 10 years, with an emphasis on their structural diversity, chemical design, exceptional properties, and potential applications. We believe that it will inspire intense, combined research efforts to enrich the family of high-performance molecular ferroelectrics and attract widespread interest from physicists and chemists to better understand the structure-function relationships governing improved applied functional device engineering.

Since the expected therapeutic results of ischemic stroke are strictly time dependent, early and accurate diagnosis as well as short intervals between diagnosis and treatment are key factors for the survival of stroke patients. In this study, we fabricated platelet (PLT) membrane-derived biomimetic nanobubbles (PNBs) for timely perfusion intervention and ultrasound imaging of acute ischemic stroke. Methods: The PNBs are fabricated by sonication-assisted reassembly of repeatedly freeze-thawed live platelet-derived PLT membrane vesicles (PMVs). The TEM, SEM, EDS and DLS were used to analyze the morphology and physicochemical properties of PNBs. The HPLC and LC-MS/MS were applied to confirm the lipid and protein compositions of PNBs. The in vitro macrophage uptake and platelet aggregation of PNBs were designed to examine the immune escape and thrombotic response characteristics. Furthermore, based on a photothrombotic ischemic stroke mouse model, the biodistribution, stroke microvascular network change, as well as cerebral blood flow of PNBs were studied by using near-infrared fluorescence imaging, multimodal optical imaging, and full-field laser perfusion imager. Finally, we assessed the brain ultrasound imaging of PNBs with a high-resolution micro-imaging system using both B-mode and contrast mode. Results: The natural lipid and protein components isolated from PLT membrane endow the PNBs with accurate lesion-targeting ability. The preferentially accumulated PNBs exhibit microvascular bio-remodeling ability of the stroke lesion, which is critical for recanalization of the obstructed vessels to protect the neural cells around the ischemic region of the stroke. Furthermore, with the increased accumulation of PNBs clusters in the lesion, PNBs in the lesion can be monitored by real-time contrast-enhanced ultrasound imaging to indicate the severity and dynamic development of the stroke. Conclusions: In summary, platelet membrane-based nanobubbles for targeting acute ischemic lesions were developed as microvascular recanalization nanoformulation for acute ischemic stroke lesion theranostics. This biomimetic PNBs theranostic strategy will be valuable for ischemic stroke patients in the future.

Solid-state molecular rotor-type materials such as host–guest inclusion compounds are very desirable for the construction of molecular ferroelectrics. However, they usually have a low Curie temperature (Tc) and uniaxial nature, severely hindering their practical applications. Herein, by regulating the anion to control “momentum matching” in the crystal structure, we successfully designed a high-temperature multiaxial host–guest inclusion ferroelectric [(MeO–C6H4–NH3)(18-crown-6)][TFSA] (MeO–C6H4–NH3 = 4-methoxyanilinium, TFSA = bis(trifluoromethanesulfonyl)ammonium) with the Aizu notation of mmmFm. Compared to the parent uniaxial ferroelectric [(MeO–C6H4–NH3)(18-crown-6)][BF4] with a Tc of 127 K, the introduction of larger TFSA anions brings a lower crystal symmetry at room temperature and a higher energy barrier of molecular motions in phase transition, giving [(MeO–C6H4–NH3)(18-crown-6)][TFSA] multiaxial ferroelectricity and a high Tc up to 415 K (above that of BaTiO3). To our knowledge, such a record temperature enhancement of 288 K makes its Tc the highest among the reported crown-ether-based ferroelectrics, giving a wide working temperature range for applications in data storage, temperature sensing, actuation, and so on. This work will provide guidance and inspiration for designing high-Tc host–guest inclusion ferroelectrics.