For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ∼26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad.soft gripper | equal load sharing | fracture mechanics | fibrillar adhesives | gecko B y exploiting principles of equal load sharing (1) and interfacial crack pinning (2), geckos' fibrillar foot-hairs can firmly adhere to a wide range of surfaces using intermolecular interactions, such as van der Waals forces (3). Using the same attachment method, gecko-inspired synthetic elastomeric fibrillar adhesives achieve bond strengths of over 100 kPa on smooth flat surfaces (4), surpassing the performance of the gecko on such surfaces (5), and exhibit quick release through peeling (6) or buckling (7) of the microfibers. For the past decade, gecko-inspired adhesives have been applied to a variety of systems including numerous robotic applications for wall climbing (8, 9), perching devices for flyers (10), and grippers (11)(12)(13)(14). However, difficulties arise in dealing with 3D surfaces because the current gecko-inspired synthetic adhesive systems are often supported by a rigid backing, which limits their ability to conform to nonplanar surfaces. In our previous work, we created elastomeric fibrillar adhesives integrated with a soft membrane, which we named as fibrillar adhesives on a membrane (FAM), and fixed the membrane onto a 3D-printed rigid plastic body so that the system could handle various 3D objects (15). Despite demonstrating a significant improvement over an unstructured elastomeric membrane with 10× higher adhesion, the tested FAM could achieve only 2 kPa of adhesion stress, a small fraction of the 55 kPa measured with rigid-backed microfiber arrays (16). This implies that the improved conformability to 3D surfaces enabled by the more compliant membrane backing is at the expense of a 96% reduction in adhesion strength. Considering that the adhesion of a membrane scales with the circumferential ...

The adhesive characteristics of fibrillar adhesives on a soft deformable membrane are reported. A soft gripper with an inflatable membrane covered by elastomer mushroom-shaped microfibers have a superior conformation to non-planar 3D part geometries, enabling the transfer printing of various parts serially or in parallel.

a b s t r a c tObjective: To fully understand the cytotoxicity of after-degradation QDs, we synthesized CdS QDs and investigated its toxicity mechanism. Methods: Biomimetic method was proposed to synthesize cadmium sulfide (CdS) QDs. Thereafter MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay was conducted to evaluate their cytotoxicity. To investigate the toxicity mechanism, we subsequently conducted intracellular reactive oxygen species (ROS) measurement with DCFH-DA, glutathione (GSH) measurement with DTNB, and cellular cadmium assay using atomic absorption spectrometer. Microsized CdS were simultaneously tested as a comparison. Results: MTT assay results indicated that CdS QDs are more toxic than microsized CdS especially at concentrations below 40 lg/ml. While microsized CdS did not trigger ROS elevation, CdS QDs increase ROS by 20-30% over control levels. However, they both deplete cellular GSH significantly at the medium concentration of 20 lg/ml. In the presence of NAC, cells are partially protected from CdS QDs, but not from microsized particles. Additionally, nearly 20% of cadmium was released from CdS nanoparticles within 24 h, which also accounts for QDs' toxicity. Conclusion: Intracellular ROS production, GSH depletion, and cadmium ions (Cd 2+ ) release are possible mechanisms for CdS QDs' cytotoxicity. We also suggested that with QD concentration increasing, the principal toxicity mechanism changes from intracellular oxidative stress to Cd 2+ release.Crown

Adding low-dose simvastatin to gemcitabine in advanced pancreatic cancer does not provide clinical benefit, although it also does not result in increased toxicity. Given the emerging role of statins in overcoming resistance to anti-EGFR treatment, further studies are justified to evaluate the efficacy and safety of combined simvastatin and anti-EGFR agents, such as erlotinib or cetuximab, plus gemcitabine for treating advanced pancreatic cancer.