CogniFiber: Harnessing Biocompatible and Biodegradable 1D Collagen Nanofibers for Sustainable Nonvolatile Memory and Synaptic Learning Applications.

Here, resistive switching (RS) devices are fabricated using naturally abundant, nontoxic, biocompatible, and biodegradable biomaterials. For this purpose, 1D chitosan nanofibers (NFs), collagen NFs, and chitosan-collagen NFs are synthesized by using an electrospinning technique. Among different NFs, the collagen-NFs-based device shows promising RS characteristics. In particular, the optimized Ag/collagen NFs/fluorine-doped tin oxide RS device shows a voltage-tunable analog memory behavior and good nonvolatile memory properties. Moreover, it can also mimic various biological synaptic learning properties and can be used for pattern classification applications with the help of the spiking neural network. The time series analysis technique is employed to model and predict the switching variations of the RS device. Moreover, the collagen NFs have shown good cytotoxicity and anticancer properties, suggesting excellent biocompatibility as a switching layer. The biocompatibility of collagen NFs is explored with the help of NRK-52E (Normal Rat Kidney cell line) and MCF-7 (Michigan Cancer Foundation-7 cancer cell line). Additionally, the biodegradability of the device is evaluated through a physical transient test. This work provides a vital step toward developing a biocompatible and biodegradable switching material for sustainable nonvolatile memory and neuromorphic computing applications.

Review of Electrochemically Synthesized Resistive Switching Devices: Memory Storage, Neuromorphic Computing, and Sensing Applications.

Resistive-switching-based memory devices meet most of the requirements for use in next-generation information and communication technology applications, including standalone memory devices, neuromorphic hardware, and embedded sensing devices with on-chip storage, due to their low cost, excellent memory retention, compatibility with 3D integration, in-memory computing capabilities, and ease of fabrication. Electrochemical synthesis is the most widespread technique for the fabrication of state-of-the-art memory devices. The present review article summarizes the electrochemical approaches that have been proposed for the fabrication of switching, memristor, and memristive devices for memory storage, neuromorphic computing, and sensing applications, highlighting their various advantages and performance metrics. We also present the challenges and future research directions for this field in the concluding section.

Recent progress in energy, environment, and electronic applications of MXene nanomaterials.

Since the discovery of graphene, two-dimensional (2D) materials have gained widespread attention, owing to their appealing properties for various technological applications. Etched from their parent MAX phases, MXene is a newly emerged 2D material that was first reported in 2011. Since then, a lot of theoretical and experimental work has been done on more than 30 MXene structures for various applications. Given this, in the present review, we have tried to cover the multidisciplinary aspects of MXene including its structures, synthesis methods, and electronic, mechanical, optoelectronic, and magnetic properties. From an application point of view, we explore MXene-based supercapacitors, gas sensors, strain sensors, biosensors, electromagnetic interference shielding, microwave absorption, memristors, and artificial synaptic devices. Also, the impact of MXene-based materials on the characteristics of respective applications is systematically explored. This review provides the current status of MXene nanomaterials for various applications and possible future developments in this field.

Microneedles of chitosan-porous carbon nanocomposites: Stimuli (pH and electric field)-initiated drug delivery and toxicological studies.

An array of microneedles (MNs) of chitosan-graphene assembled in porous carbon (CS-GAPC) nanocomposites has been synthesized and evaluated. The safety of the formulated system has been ensured using detailed in vivo toxicological studies and efficacy has been ensured by evaluating the stimuli (pH and electric field) initiated drug delivery properties. Drug cephalexin has been incorporated in these MNs. In vivo toxicological studies of CS-GAPC nanocomposite were performed on Sprague rats, using acute dermal and subacute dermal (ADT& SADT) test, histopathological studies, biochemical studies, and AMES tests. ADT and SADT studies showed that median lethal dose (LD50 ) was found greater than 2000 mg/kg body weight; with no abnormal weight gain and food consumption, during the study period of 28 days. This study showed that administration of CS-GAPC did not cause any substantial alterations in hematological and biochemical parameters of the animals. Histopathological studies showed no significant changes in the control and CS-GAPC administered groups. AMES tests reveal that CS-GAPC nanocomposite is nonmutagenic against the Salmonella thyphimurium strains. No abnormalities were observed in the animal's chromosomal aberrations and clastogenic values when the animals were treated with CS-GAPC. At acidic pH of 4, the encapsulated drug was completely released, indicating that the drug release from the prepared nanocomposite is pH dependent. An electric field of 5 V showed optimum drug release, as a function of applied electric pulses. A biologically safe drug encapsulation model system is hence projected for smart drug delivery (pH dependent and electric field triggered) using the microneedle approach. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1582-1596, 2019.