Although electrically stimulated neurite outgrowth on bioelectronic devices is a promising means of nerve regeneration, immunogenic scar formation can insulate electrodes from targeted cells and tissues, thereby reducing the lifetime of the device. Ideally, an electrode material capable of electrically interfacing with neurons selectively and efficiently would be integrated without being recognized by the immune system and minimize its response. Here we develop a cell membrane-mimicking conducting polymer possessing several attractive features. This polymer displays high resistance towards nonspecific enzyme/cell binding and recognizes targeted cells specifically to allow intimate electrical communication over long periods of time. Its low electrical impedance relays electrical signals efficiently. This material is capable to integrate biochemical and electrical stimulation to promote neural cellular behaviour. Neurite outgrowth is enhanced greatly on this new conducting polymer; in addition, electrically stimulated secretion of proteins from primary Schwann cells can also occur on it.
Unlike tumor biopsies that can be constrained by problems such as sampling bias, circulating tumor cells (CTCs) are regarded as the “liquid biopsy” of the tumor, providing convenient access to all disease sites, including primary tumor and fatal metastases. Although enumerating CTCs is of prognostic significance in solid tumors, it is conceivable that performing molecular and functional analyses on CTCs will reveal much significant insight into tumor biology to guide proper therapeutic intervention. We developed the Thermoresponsive NanoVelcro CTC purification system that can be digitally programmed to achieve an optimal performance for purifying CTCs from non-small cell lung cancer (NSCLC) patients. The performance of this unique CTC purification system was optimized by systematically modulating surface chemistry, flow rates, and heating/cooling cycles. By applying a physiologically endurable stimulation (i.e., temperature between 4 and 37 °C), the mild operational parameters allow minimum disruption to CTCs’ viability and molecular integrity. Subsequently, we were able to successfully demonstrate culture expansion and mutational analysis of the CTCs purified by this CTC purification system. Most excitingly, we adopted the combined use of the Thermoresponsive NanoVelcro system with downstream mutational analysis to monitor the disease evolution of an index NSCLC patient, highlighting its translational value in managing NSCLC.
Nanographene, a small piece of graphene, has attracted unprecedented interest across diverse scientific disciplines particularly in organic electronics. The biological applications of nanographenes, such as bioimaging, cancer therapies and drug delivery, provide significant opportunities for breakthroughs in the field. However, the intrinsic aggregation behavior and low solubility of nanographenes, which stem from their flat structures, hamper their development for bioapplications. Herein, we report a water-soluble warped nanographene (WNG) that can be easily synthesized by sequential regioselective C-H borylation and cross-coupling reactions of the saddle-shaped WNG core structure. The saddle-shaped structure and hydrophilic tetraethylene glycol chains impart high water solubility to the WNG. The water-soluble WNG possesses a range of promising properties including good photostability and low cytotoxicity. Moreover, the water-soluble WNG was successfully internalized into HeLa cells and promoted photoinduced cell death.
This paper presents a study for modeling harmonic currents injected by three-level pulse-width-modulated (PWM) converters of the high-speed railway traction drive in steady-state motoring mode. An analytical solution for converter harmonics based on the double Fourier series theory is described. The time-domain simulation results obtained by the use of PSpice are then compared with those obtained by the proposed model. It is shown that the harmonic currents determined according to the proposed model agree well with those results obtained by using the time-domain simulation tool.
Tailoring the surface of biometallic implants with protein-resistant polymer brushes represents an efficient approach to improve the biocompability and mechanical compliance with soft human tissues. A general approach utilizing electropolymerization to form initiating group (-Br) containing poly(3,4-ethylenedioxythiophen)s (poly(EDOT)s) is described. After the conducting polymer is deposited, neutral poly((oligo(ethylene glycol) methacrylate), poly(OEGMA), and zwitterionic poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide), poly(SBMA), brushes are grafted by surface-initiated atom transfer radical polymerization. Quartz crystal microbalance (QCM) experiments confirm protein resistance of poly(OEGMA) and poly(SBMA)-grafted poly(EDOT)s. The protein binding properties of the surface are modulated by the density of polymer brushes, which is controlled by the feed content of initiator-containing monomer (EDOT-Br) in the monomer mixture solution for electropolymerization. Furthermore, these polymer-grafted poly(EDOT)s also prevent cells to adhere on the surface.
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