A paradigm-shifting design strategy is demonstrated that unifies the treatment of electronic and conformational properties of polymer dielectrics for concurrent high electric field and elevated temperature harsh conditions.

Exploiting contact lenses for ocular drug delivery is an emerging field in the area of biomedical engineering and advanced healthcare materials. Despite all the research conducted in this area, still, new technologies are in their early stages of the development, and more work must be done in terms of clinical trials to commercialize these technologies. A great challenge in using contact lenses for drug delivery is to achieve a prolonged drug release profile within the therapeutic range for various eye‐related problems and diseases. In general, desired release kinetics to avoid the initial burst release is the zero‐order kinetics within the therapeutic range. This review highlights the new technologies developed to achieve efficient and extended drug delivery. It also provides an overview of the materials and methods for fabrication of contact lenses and their mechanical and optical properties.

Degradable electronics represent a rapidly emerging field of science and technology with the potential to serve short-term medical implantation applications where the device disappears once its function is complete. Despite many efforts in developing new types of degradable electronics, many of such systems are nonelastic and incompatible with the dynamic motion of native soft/elastic biological tissues. Herein, a photo-crosslinkable hydrogel with integrated electronics that are highly stretchable and degradable in liquid environments is demonstrated. The fabrication process takes advantage of facile laser micromachining of conductive patterns directly onto the hydrogel under ambient conditions and permanent hydrogel-hydrogel bonding. The robustness and degradation rate of hydrogel and the laser-processed encapsulated stretchable circuits is systematically investigated in different solutions under various conditions. Biocompatibility tests with non-neoplastic cells (HMT 3522 S1) and cancer cells (T4-2 and MDA-MB-231) are performed in 2D and 3D cell culture systems to confirm instead of evaluate the safety of the hydrogel and its byproducts during degradation as well as the zinc metal used in this technology. As a proof of concept, a stretchable hydrogel-based device that can be used for remote/wireless delivery of thermal energy into the tissue in contact with the hydrogel is fabricated.

Chronic nonhealing wounds are a growing socioeconomic problem that affects more than 6 million people annually solely in the United States. These wounds are colonized by bacteria that often develop into biofilms that act as a physical and chemical barrier to therapeutics and tissue oxygenation leading to chronic inflammation and tissue hypoxia. Although wound debridement and vigorous mechanical abrasion techniques are often used by clinical professionals to manage and remove biofilms from wound surfaces, such methods are highly nonselective and painful. In this study, we have developed a flexible polymer composite microneedle array that can overcome the physicochemical barriers (i.e., bacterial biofilm) present in chronic nonhealing wounds and codeliver oxygen and bactericidal agents. The polymeric microneedles are made by using a facile UV polymerization process of polyvinylpyrrolidone and calcium peroxide onto a flexible polyethylene terephthalate substrate for conformable attachment onto different locations of the human body surface. The microneedles effectively elevate the oxygen levels from 8 to 12 ppm once dissolved over the course of 2 h while also providing strong bactericidal effects on both liquid and biofilm bacteria cultures of both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacterial strains commonly found in dermal wounds. Furthermore, the results from the ex vivo assay on a porcine wound model indicated successful insertion of the microneedles into the tissue while also providing effective bactericidal properties against both Gram-positive and Gram-negative within the complex tissue matrix. Additionally, the microneedles demonstrate high levels of cytocompatibility with less than 10% of apoptosis throughout 6 days of continuous exposure to human dermal fibroblast cells. The demonstrated flexible microneedle array can provide a better approach for increasing the effectiveness of topical tissue oxygenation as well as the treatment of infected wounds with intrinsically antibiotic resistant biofilms.

Printed electronics are circuits that are additively manufactured using conductive pastes composed of micro-/nanoconductive metal particles. Silver-based compounds are the most widely used metals for such pastes due to their superior conductivity and oxidation stability. However, the high cost of silver (Ag) has demanded its replacement with more cost-effective and abundant metals such as copper (Cu). Despite its cost-effectiveness and abundance, Cu suffers from high oxidation tendency and sintering temperature that have limited its widespread utilization in printed electronics. In this work, we have developed a low-cost hybrid bimodal paste composed of Cu microparticles (1–5 μm) and Ag nanoparticles (20–30 nm) (CuMPs/AgNPs) via nondestructive photonic sintering. The concurrent melting of AgNPs and catalytic reduction of CuMPs allow the paste to be sintered at considerably low temperatures using an intense-pulsed light (IPL) source. The required light energy density for effective sintering of different mixing ratios of AgNPs and CuMPs was systematically measured using electrical, optical, and mechanical characterization techniques. These analyses revealed that a minimum of 16 wt % AgNPs in the bimodal CuMP/AgNP paste with an IPL irradiation energy of 10.6 J/cm2 and pulse duration of 5 ms achieved a minimum sheet resistance of 0.072 Ω/□ that results from localized melting of AgNPs between adjacent CuMPs. Furthermore, the CuMP/AgNP films with a minimum of 6 wt % AgNPs showed significantly improved oxidation stability characteristics even after 7 days of incubation in accelerated oxidation conditions [70 °C and 100% relative humidity (RH)]. As a proof of concept, we demonstrated an application of the developed paste (CuMPs-6 wt % AgNPs) by directly printing a wireless resonant moisture sensor onto the interior region of a cardboard package box, which is capable of performing in situ monitoring of the moisture ranging from 30 to 85% RH with an average linear sensitivity of −3.08 % RH/MHz.