Fiber-tip polymer clamped-beam probe for high-sensitivity nanoforce measurements

Micromanipulation and biological, material science, and medical applications often require to control or measure the forces asserted on small objects. Here, we demonstrate for the first time the microprinting of a novel fiber-tip-polymer clamped-beam probe micro-force sensor for the examination of biological samples. The proposed sensor consists of two bases, a clamped beam, and a force-sensing probe, which were developed using a femtosecond-laser-induced two-photon polymerization (TPP) technique. Based on the finite element method (FEM), the static performance of the structure was simulated to provide the basis for the structural design. A miniature all-fiber micro-force sensor of this type exhibited an ultrahigh force sensitivity of 1.51 nm μN−1, a detection limit of 54.9 nN, and an unambiguous sensor measurement range of ~2.9 mN. The Young’s modulus of polydimethylsiloxane, a butterfly feeler, and human hair were successfully measured with the proposed sensor. To the best of our knowledge, this fiber sensor has the smallest force-detection limit in direct contact mode reported to date, comparable to that of an atomic force microscope (AFM). This approach opens new avenues towards the realization of small-footprint AFMs that could be easily adapted for use in outside specialized laboratories. As such, we believe that this device will be beneficial for high-precision biomedical and material science examination, and the proposed fabrication method provides a new route for the next generation of research on complex fiber-integrated polymer devices.

Soft robotic steerable microcatheter for the endovascular treatment of cerebral disorders

Catheters used for endovascular navigation in interventional procedures lack dexterity at the distal tip. Neurointerventionists, in particular, encounter challenges in up to 25% of aneurysm cases largely due to the inability to steer and navigate the tip of the microcatheters through tortuous vasculature to access aneurysms. We overcome this problem with submillimeter diameter, hydraulically actuated hyperelastic polymer devices at the distal tip of microcatheters to enable active steerability. Controlled by hand, the devices offer complete 3D orientation of the tip. Using saline as a working fluid, we demonstrate guidewire-free navigation, access, and coil deployment in vivo, offering safety, ease of use, and design flexibility absent in other approaches to endovascular intervention. We demonstrate the ability of our device to navigate through vessels and to deliver embolization coils to the cerebral vessels in a live porcine model. This indicates the potential for microhydraulic soft robotics to solve difficult access and treatment problems in endovascular intervention.

Soft robotic steerable micro-catheter for the endovascular treatment of cerebral disorders

Catheters used for endovascular navigation in interventional procedures lack dexterity at the distal tip. Neurointerventionists, in particular, encounter challenges in up to 25% of aneurysm cases largely due to the inability to steer and navigate the tip of the micro-catheters through tortuous vasculature to access aneurysms. We overcome this problem with sub-millimeter diameter, hydraulically-actuated hyperelastic polymer devices at the distal tip of micro-catheters to enable active steerability. Controlled by hand, the devices offer complete 3D orientation of the tip. Using pressures up to 400 kPa (4 atm) we demonstrate guidewire-free navigation, access, and coil deployment in vivo, offering safety, ease of use, and design flexibility absent in other approaches to endovascular intervention. We demonstrate the ability of our device to navigate through vessels and to deliver embolization coils to the cerebral vessels in a live porcine model. This indicates the potential for microhydraulic soft robotics to solve difficult access and treatment problems in endovascular intervention.

Local Orientation of Chains at Crystal/Amorphous Interfaces Buried in Isotactic Polypropylene Thin Films

A better understanding of the aggregation states of polymer chains in thin films is of pivotal importance for developing thin film polymer devices in addition to its inherent scientific interest....