A 3D-printed microfluidic-enabled hollow microneedle architecture for transdermal drug delivery.

Embedding microfluidic architectures with microneedles enables fluid management capabilities that present new degrees of freedom for transdermal drug delivery. To this end, fabrication schemes that can simultaneously create and integrate complex millimeter/centimeter-long microfluidic structures and micrometer-scale microneedle features are necessary. Accordingly, three-dimensional (3D) printing techniques are suitable candidates because they allow the rapid realization of customizable yet intricate microfluidic and microneedle features. However, previously reported 3D-printing approaches utilized costly instrumentation that lacked the desired versatility to print both features in a single step and the throughput to render components within distinct length-scales. Here, for the first time in literature, we devise a fabrication scheme to create hollow microneedles interfaced with microfluidic structures in a single step. Our method utilizes stereolithography 3D-printing and pushes its boundaries (achieving print resolutions below the full width half maximum laser spot size resolution) to create complex architectures with lower cost and higher print speed and throughput than previously reported methods. To demonstrate a potential application, a microfluidic-enabled microneedle architecture was printed to render hydrodynamic mixing and transdermal drug delivery within a single device. The presented architectures can be adopted in future biomedical devices to facilitate new modes of operations for transdermal drug delivery applications such as combinational therapy for preclinical testing of biologic treatments.

A wearable electrofluidic actuation system.

We report a wearable electrofluidic actuation system, which exploits the alternating current electrothermal (ACET) effects to engineer biofluid flow profiles on the body. The wearable ACET flow is induced with the aid of corrosion-resistant electrode configurations (fabricated on a flexible substrate) and custom-developed, wirelessly programmable high frequency (MHz) excitation circuitry. Various tunable flow profiles are demonstrated with the aid of the devised flexible ACET electrode configurations, where the induced profiles are in agreement with the ACET theory and simulation. The demonstrated capabilities rendered by the presented system create new degrees of freedom for implementing advanced bioanalytical operations for future lab-on-the-body platforms.

A rapid and low-cost fabrication and integration scheme to render 3D microfluidic architectures for wearable biofluid sampling, manipulation, and sensing.

The large-scale deployment of wearable bioanalytical devices for general population longitudinal monitoring necessitates rapid and high throughput manufacturing-amenable fabrication schemes that render disposable, low-cost, and mechanically flexible microfluidic modules capable of performing a variety of bioanalytical operations within a compact footprint. The spatial constraints of previously reported wearable bioanalytical devices (with microfluidic operations confined to 2D), their lack of biofluid manipulation capability, and the complex and low-throughput nature of their fabrication process inherently limit the diversity and frequency of end-point assessments and prevent their deployment at large scale. Here, we devise a simple, scalable, and low-cost "CAD-to-3D Device" fabrication and integration scheme, which renders 3D and complex microfluidic architectures capable of performing biofluid sampling, manipulation, and sensing. The devised scheme is based on laser-cutting of tape-based substrates, which can be programmed at the software-level to rapidly define microfluidic features such as a biofluid collection interface, microchannels, and VIAs (vertical interconnect access), followed by the vertical assembly of pre-patterned layers to realize the final device. To inform the utility of our fabrication scheme, we demonstrated three representative devices to perform sweat collection (with visualizable secretion profile), sample filtration, and simultaneous biofluid actuation and sensing (using a sandwiched-interface). Our devised scheme can be adapted for the fabrication and manufacturing of current and future wearable bioanalytical devices, which in turn will catalyze the large-scale production and deployment of such devices for general population health monitoring.