Abstract: Systems and methods relate to applying a coating to a substrate. Coatings can be generated using layer-by-layer application techniques. Typically, application of a first aqueous solution is alternated with application of a second aqueous solution. Example first aqueous solutions include polyethyleneimine (PEI) and hydroxy-terminated poly(dimethylsiloxane) (PDMS-OH). Example second aqueous solutions include silicate and PDMS-OH. In some instances, first aqueous solutions and/or second aqueous solutions additionally include methyl-terminated PDMS (PDMS-CH3).

Abstract: A novel methodology of forming a three-dimensional electronic device according to various embodiments of the present invention is described. The methodology comprises, at least, a step of laser folding, using only a laser, a two-dimensional electrically insulating printed circuit board at least partially covered with at least one metal layer, with the laser impinging upon the at least one metal layer to make one or more folds of the printed circuit board to form a three-dimensional electronic device structure.

Abstract: Various examples are provided related to interstitial fluid (ISF) or extracellular fluid (ECF) harvesting and processing. In one example, a microfluidic monitoring platform includes a microneedle patch including microneedles on a first side; an osmotic patch on a second side of the microneedle patch that includes glycerogel or hydrogel equilibrated with glycerin or glucose; and a microfluidic or fluid transport film or material channel between the osmotic patch and the microneedle patch. The channel can extract fluid from the osmotic-microneedle patch complex. In another example, a wearable electrochemical sensing system includes a monitoring platform including a microneedle-osmotic patch, a microfluidic or fluid transport film or material channel, and at least one sensor between the channel; and processing circuitry coupled to the at least one sensor. The processing circuitry can monitor presence of a chemical or biomarker in the fluid based upon signals obtained from the sensor.

Abstract: Systems and methods relate to applying a coating to a substrate. Coatings can be generated using layer-by-layer application techniques. Typically, application of a first aqueous solution is alternated with application of a second aqueous solution. Example first aqueous solutions include polyethyleneimine (PEI) and hydroxy-terminated poly(dimethylsiloxane) (PDMS-OH). Example second aqueous solutions include silicate and PDMS-OH. In some instances, first aqueous solutions and/or second aqueous solutions additionally include methyl-terminated PDMS (PDMS-CH3).

Abstract: Microfluidic devices are provided for continuous sampling of biological fluid for extended periods of time, e.g. for periods of time up to and including 10 days. The microfluidic devices can be made from porous hydrophilic substrate, e.g. hydrophilic paper substrates. The devices can include a collection pad, an evaporative pump, and a channel connecting the collection pad and the evaporative pump. Hydrogels at the collection pad can promote collection of sweat or other biological fluids from a subject, which in some aspects is assisted by the use of one or more microneedles on the substrate. An evaporative pump can provide for long periods of sampling by providing continual pumping, e.g. through the use of an evaporation pad where sampled fluid can evaporate.

Abstract: Flexible thermoelectric generators and methods of manufacturing are disclosed. In one embodiment, a flexible thermoelectric generator includes a plurality of pillars, a first and a second plurality of flexible interconnects, and a flexible material. The plurality of pillars having a first side and a second side. The first plurality of flexible interconnects electrically connecting pairs of the plurality of pillars on the first side. The second plurality of flexible interconnects electrically connecting the pairs of plurality of pillars on the second side. The first and the second plurality of flexible interconnects alternate among the pairs of plurality of pillars to form an electrical circuit having a first end and a second end. The flexible material covering the first and second plurality of flexible interconnects and having an external surface. The flexible material is configured to conduct thermal energy from the external surface to the plurality of pillars.

Abstract: Surface-modified polymer compositions are provided. The surface-modified polymer compositions can include a polymer and a multifunctional linker. The surface-modified polymer compositions can include a polymer, a multifunctional linker, and a surface group. Aqueous-based processes can be used to fabricate the surface-modified polymer compositions.

Abstract: Surface-modified polymer compositions are provided. The surface-modified polymer compositions can include a polymer and a multifunctional linker. The surface-modified polymer compositions can include a polymer, a multifunctional linker, and a surface group. Aqueous-based processes can be used to fabricate the surface-modified polymer compositions.

Abstract: A flexible stretchable sensor, methods of use, and methods of forming the same are disclosed herein. In one implementation, the flexible stretchable sensor comprises a plurality of flexible and stretchable fibers in close proximity to one another, wherein each of the flexible fibers comprises a hollow electrically insulating elastomeric fiber at least partially filled with a flexible and stretchable conductive material and an electrical connector in electrical communication with the flexible and stretchable conductive material, wherein a change in an electrical parameter of at least one of the plurality of flexible and stretchable fibers is used to sense an event associated with the at least one of the plurality of flexible and stretchable fibers.

Abstract: Flexible thermoelectric generators and methods of manufacturing are disclosed. In one embodiment, a flexible thermoelectric generator includes a plurality of pillars, a first and a second plurality of flexible interconnects, and a flexible material. The plurality of pillars having a first side and a second side. The first plurality of flexible interconnects electrically connecting pairs of the plurality of pillars on the first side. The second plurality of flexible interconnects electrically connecting the pairs of plurality of pillars on the second side. The first and the second plurality of flexible interconnects alternate among the pairs of plurality of pillars to form an electrical circuit having a first end and a second end. The flexible material covering the first and second plurality of flexible interconnects and having an external surface. The flexible material is configured to conduct thermal energy from the external surface to the plurality of pillars.

Abstract: Methods of printing metallic objects include providing parameters of an object for printing, and controlling a deposition of a fluid metallic material to form the object. At least an outer surface region of the fluid metallic material is converted to a solid region after deposition.

Abstract: Paper-based microfluidic systems and methods of making the same are described.

Abstract: Hydrophilic threads as platforms for inexpensive, low volume, portable diagnostic systems, and methods of making the same are described. A diagnostic system includes a hydrophilic loading thread having an inlet zone at a proximal end; a testing zone at a distal end; and an intermediate zone located between the inlet zone and the testing zone, wherein the testing zone does not directly contact the inlet zone. In another aspect, a diagnostic system includes (i) a hydrophilic loading thread that includes an inlet zone at a proximal end and an intermediate zone at a distal end; and (ii) one or more additional hydrophilic threads that contact the intermediate zone of the loading thread.

Abstract: Hydrophilic threads as platforms for inexpensive, low volume, portable diagnostic systems, and methods of making the same are described. A diagnostic system includes a hydrophilic loading thread having an inlet zone at a proximal end; a testing zone at a distal end; and an intermediate zone located between the inlet zone and the testing zone, wherein the testing zone does not directly contact the inlet zone. In another aspect, a diagnostic system includes (i) a hydrophilic loading thread that includes an inlet zone at a proximal end and an intermediate zone at a distal end; and (ii) one or more additional hydrophilic threads that contact the intermediate zone of the loading thread.

Abstract: Paper-based microfluidic systems and methods of making the same are described.