In recent years, tremendous efforts have been made to investigate tribomaterials for triboelectric nanogenerators (TENGs), but due to their low performance there is still need of tribomaterials with new mechanisms for performance enhancement. Therefore, in this study, the potential of conducting polyaniline and tribonegative graphene oxide is exploited for performance enhancement of tribopositive material through a new mechanism of disturbing the equilibrium state inside the tribopositive material under an impact force. Thus, a TENG device made up of polymer with 700 µL polyaniline and 4 mg mL−1 graphene oxide as tribopositive and polydimethylsiloxane as a tribonegative layer with a dimension of 1 × 2 cm2 is able to produce an open‐circuit voltage of 314.92 V and a current density of 37.81 mA m−2 with a peak power density of 10.43 W m−2, which can directly power ON more than 175 white light‐emitting diodes. Amine group of polyaniline and its pathway to mobilize electrons inside the tribopositive material due to electron accepting ability of graphene oxide upon physical contact under external force are the main contributing factors toward performance enhancement. This work introduces a low cost, easy fabrication process with a new method for performance enhancement of tribopositive material to acquire a high performance TENGs.

A microfluidic platform that integrates precise temperature control and multi-oocyte capture is proposed for investigation of oocyte osmotic responses.

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Triboelectric nanogenerators (TENGs) are attractive research since their discovery, and various strategies are developed in order to improve their output performance. Recently, the ionic gel has been attracted to the TENGs field, but it typically has limited power output and durability. Here, a strategy of adding silica‐supported ionic liquid to the polymer (solid polymer electrolyte) as a triboelectric material is reported. This method of tribo‐material is created using a straightforward sol–gel process, resulting in a versatile, stable, durable, and high power output performance. When coupled with spin‐coated polydimethylsiloxane as negative material provides an output voltage of 248 V, a current density of 61.5 mA m−2 and power density of 5.2 W m−2 which is sufficient to light up 160 white light‐emitting diodes. Comparatively, pristine poly(vinyl alcohol) (PVA) film merely harvests 125 V, 26.5 mA m−2, and power of ≈2.48 W m−2. The high output is attributed to the silica precursor in the membrane, which makes more –OH groups of PVA to form long chains network with other oxygen of alkoxy groups through hydrogen bonding and also the presence of nitrogen groups of imidazolium. This work thus expands the enhancement of the positive material utilized for triboelectric nanogenerators with high possibility.

Vitrification has become one of the promising cryopreservation methods for biosamples including cells and tissues because the vitreous state reduces the damage of ice crystals to cells. However, besides extremely high cooling rates, routine vitrification protocols require a high concentration of penetrating cryoprotectants (pCPAs, ∼6−8 M), which is toxic for cells and brings trouble when removing pCPAs. Therefore, reducing the concentration of toxic pCPAs in vitrification remains a challenge, and advanced strategies are urgently needed. Hydrogel encapsulation has become one effective method to achieve low-cryoprotectant (CPA) concentration preservation of stem cells with rapid cooling, but there are very few related studies about endothelial cells (ECs). In this study, we achieved pCPA concentration (up to 3 M) vitrification by encapsulating human umbilical vein endothelial cells (HUVECs) into core−shell alginate hydrogel microcapsules. Alginate encapsulation increased HUVEC cryosurvival up to 80%, which is 60% improvement compared to control without encapsulation. Furthermore, two different sizes of capsules (diameter: ∼900 and 400 μm) were produced to explore the effects of microcapsule volume on the cell preservation results, and it was found that larger capsules (∼900 μm) have no significant effect on cell survival while improving encapsulation efficiency. This encapsulation method provides a new strategy for EC preservation and serves as an improvement to optimize the preservation of biosamples.

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