Tailored diffusion limiting membrane for microneedle glucose sensors with wide linear range.

Continuous glucose monitoring is very important to daily blood glucose control in diabetic patients, but its accuracy is limited by the narrow linear range of the response of biosensor to the glucose concentration because of the oxygen starvation in tissue and the limited maximum conversion rate of glucose oxidase. In this work, a biocompatible diffusion limiting membrane based on two medical-grade polyurethanes is developed via blending modification to restrict the diffusion flux of glucose to match the oxygen concentration and the maximum conversion rate. The expansiveness of the linear range for the nanomaterials-modified electrode in the glucose biosensor can be achieved through the regulation of two polyurethanes, the solvent, and the thickness of the membrane. In addition, the mass transport of hydrogen peroxide and interfering substances is also limited of the membrane. The in vitro experiments demonstrated that the membrane-modified microneedle biosensor exhibited a rapid response to the concentration variation of glucose, a wide linear range that is sufficient to cover the blood concentration of healthy and diabetic people, the ability to resist the oxygen concentration fluctuation and interfering substances, good reproducibility and long-term stability. The custom wearable electrochemical system, possessing these characteristics, has been proven to accurately monitor the blood concentration in a living rat in real time. This demonstrates a significant potential for application in both daily and clinical blood glucose monitoring.

Multilayer track-etched membrane-based electroosmotic pump for drug delivery.

Herein, we report an electroosmotic pump (EOP) based on a multilayer track-etched polycarbonate (PC) membrane. A remarkable increase of maximum backpressure (198.2-2400 mmH2 O) of a fundamental pump unit was obtained at 0.8 mA, when the number of PC membranes was increased from 1 to 10. Meanwhile, the corresponding flow rate was increased from 80.3 to 111.7 µL/min. Furthermore, multiple pump units were assembled in series to obtain a multistage EOP. For a three-stage EOP (EOP-3), the operating voltage and power can be decreased significantly by 52%-72% under different driving currents, with a minimum power of 26.7 µW. Thus, EOP-3 can run stably over 35 h at a pulse current of 0.1 mA without the generation of gas bubbles. The pump was further integrated into a miniature device, which was successfully used to decrease the blood glucose level of diabetic rats by subcutaneous delivery of fast-acting insulin. This work brings a facile and efficient strategy to enhance the backpressure and lower the operating voltage and power of EOPs, which may find promising applications in drug delivery.

Multifunctional STING-Activating Mn3 O4 @Au-dsDNA/DOX Nanoparticle for Antitumor Immunotherapy.

The promise of immunotherapy for cancer therapy has not been fully fulfilled because portions of tumors are immunosuppressive. To tackle this challenge, the initiation of immune system by stimulator of interferon genes (STING) pathway is explored and multifunctional STING-activating nanoparticles are rationally designed for synergistic antitumor therapy. The STING-activating nanoparticles have a formulation of Mn3 O4 @Au-dsDNA/DOX, where dsDNA is used to activate STING for immunotherapy and doxorubicin (DOX) is chosen as a model drug for chemotherapy. The STING-mediated immunity is activated, inducing interferon-ß (IFN-ß) production, increasing T cell priming, and enhancing effector T cell infiltration. Combined with chemotherapy, STING-mediated immunotherapy shows good antitumor efficacy by inhibiting tumor growth and prolonging survival rate in vivo. The promise of cancer immunotherapy can be fulfilled by combining novel antitumor immunity with innovative nanotechnology, and chemotherapy and targeted therapies.

Correction: Gold alloy-based nanozyme sensor arrays for biothiol detection.

Correction for 'Gold alloy-based nanozyme sensor arrays for biothiol detection' by Junshu Lin et al., Analyst, 2020, .

Gold alloy-based nanozyme sensor arrays for biothiol detection.

Biothiols play an important role in living cells and are associated with many diseases. Thus, it is necessary to develop a facile, cost-effective, and convenient analytical method for the detection of biothiols. Nanozymes are functional nanomaterials with enzymatic activities. Due to their unique advantages (e.g., low cost, high stability, and multifunctionality), nanozymes have been extensively used to construct sensing systems. Previous studies demonstrated colorimetric assays for biothiol detection because they could competitively inhibit the peroxidase-like activities of nanozymes. However, few studies were able to differentiate biothiols from each other. To address these challenges, herein, we first synthesized Au alloy nanozymes with better peroxidase-like activities than gold nanoparticles (AuNPs). Then, cross-reactive sensor arrays were constructed with three alloy nanozymes. Six typical biothiols (i.e., glutathione, cysteine, dithiothreitol, mercaptoacetic acid, mercaptoethanol, and mercaptosuccinic acid) were successfully detected and discriminated by the as-prepared nanozyme sensor arrays. Moreover, the practical application of the nanozyme sensor arrays was demonstrated by discriminating biothiols in serum successfully.