Printed electronic devices fabricated using additive manufacturing (AM) processes such as inkjet printing, [1] screen printing, [2] and aerosol printing [3] typically utilize silver or copper for conductors because of their high electrical conductivity and chemical inertness. These two metals can be readily printed using a large variety of commercially available inks including nanoparticle, [4] metallo-organic decomposition (MOD), [5] and inorganic metal salt-based inks. [6] These materials can be processed at low temperature using chemical, [7] photonic, [8] plasma, [9] electrical, [10] microwave, [11] and thermal sintering techniques, enabling the use of low-cost plastics (such as polyesters) as substrates. This combination of print-based manufacturing methods and low-cost materials makes printed electronic devices well suited for large-area or large-number distributed applications, such as item tracking, [12] or environmental monitoring, [13] which could potentially lead to significant amounts of electronic waste if widely implemented. [14] Recently, biodegradable materials have been developed to fabricate electronic devices that can dissolve in biological fluids or decompose in the natural environment. [15] This technology could potentially revolutionize printed electronics applications by reducing electronic waste and facilitating rapid recycling. [16] Instead of silver or copper, printed biodegradable devices use water-soluble, biologically benign metallic elements for electrical conductors such as magnesium, [17] zinc, [18] molybdenum, [19] and iron, [20] which pose minimal threat to life and the environment. These metals can be oxidized and subsequently dissolved in water to form minerals. [21] As only small amounts of zinc are present in the devices, the concentrations of the minerals added to soil by biodegradable conductors are typically lower than the amount already present in the soil and required by the crop. [22] Compared with biocompatible and bioinert metals such as gold and platinum, biodegradable metals are more widely available and less cost prohibitive and potentially well suited for disposable or temporary printed electronics applications. [23] The degradation rate of printed biodegradable devices can be tuned by passivating the readily degradable metals with more slowly degrading polymer encapsulation materials so that the devices remain functional for a tunable period ranging from several days to several months. [24] A challenge in biodegradable device fabrication is formulating and printing conductive metallic inks with high conductivity. [25] Unlike inert metals, biodegradable metals have high oxidation potentials; therefore, instead of solution-based chemical synthesis, nanoparticles are typically obtained through high-energy ball milling of bulk metals. [26] Without the presence of chemical stabilizing and reducing agents, mechanical synthesis normally yields metal-metal oxide core-shell nanoparticles. [27] Noninert metal particles such as copper have inherent tendency to oxidize in a...

In this paper, we show that the surface morphology of silver (Ag) structures prepared by plasma conversion of particle-free inks can be controlled by the solvent because of evaporation effects....

Objective: Wound dressings that create and maintain a moist environment provide the optimal conditions for wound healing by increasing the rate of epithelialization and angiogenesis. However, current wound dressings require periodic removal which exposes the wound to the surrounding environment, thereby increasing the likelihood for infection and drying out the wound itself. There remains an unmet medical need for the development of an absorbent, flexible, and transparent wound dressing that can conform to the irregular geometry of the wound for a long-term duration. Herein, we report the development of AFTI Derm, an Absorbent, Flexible, Transparent, and Inexpensive moisture-management wound dressing using Polyvinyl alcohol (PVA) as the host material. Methods: AFTI Derm substrates of varying glycerol concentrations (1 wt%, 3 wt%, 5 wt%, 7 wt%, and 10 wt%) were fabricated and tested. The mechanical, absorption, and biological properties of AFTI Derm were evaluated. Results: We found that 5% glycerol served as the optimal concentration for AFTI Derm. The biocompatibility, absorptive capabilities, and scalability render PVA/glycerol an ideal material composition for wound dressings. Benchtop experimentation and pre-clinical testing demonstrate AFTI Derm as a platform for use in wound dressings. Discussion/Conclusion: The development of AFTI Derm broadens the translational utility of this materials platform not only as a material for wound dressings to minimize dressing changes in low to moderate exudate environments, but also as a potential substrate material for smart bandages. Clinical and Translational Impact Statement— AFTI Derm, an absorbent, flexible, and transparent wound dressing, maintains the moist environment required for healing while enabling monitoring of healing without removal and disruption to the wound bed.

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Neural activity that occur during motor movement, speech, thought, and various other events can be observed in the form of brainwaves composed of synchronized electrical pulses emitted from adjoining communicative neurons. Observations of these brainwaves have been made possible through neurodevices, which can detect changes in electrical and/or mechanical parameters. For decades, the field of neuroscience has been enriched by the utilization of neurotechnologies at the microscale, which has begun to gain further enhancement with the introduction of nanotechnology. For example, microelectrodes were initially used for only extracellular measurements, but over the past decade, developments have been made to also record intracellular signals. Likewise, nanoknives, which gained popularity due to their versatility, can now be used for both fabricating bio-Micro-Electro-Mechanical Systems (MEMS) and also as a neurosurgery tool. Thus, considerable efforts have been made over the years to make micro- and nanosystems reliable, accurate, and sensitive to neural activity. In the late 20th century, several sophisticated technologies, including magnetic resonance imaging (MRI), computed tomography (CT), and intracranial pressure (ICP) monitoring have been integrated with MEMS. Furthermore, existing biotechnologies are being miniaturized at both the system and component level. For example, there is a remarkable interest in the field of neuroscience to utilize microfluidic technology as a diagnostic tool using specimens such as cerebrospinal fluid (CSF). Microfluidic devices are also employed as biocompatible drug delivery systems to target cells, tissues, and organs. This paper summarizes the recent developments in micro- and nano-scale neurotechnologies, including devices, fabrication processes, detection methods, their implementation challenges, in neural stimulation, monitoring, and drug delivery. This review discusses recent developments in micro and nanotechnologies, fabrication methods, and their implementation in neuroimaging, neurostimulation, monitoring of neural activities, and neural drug delivery.