Multifunctional Poly(3,4-ethylenedioxythiophene)/Crystalline Nanofibrous Cellulose Composites for Eco-Friendly and Sustainable Electronics.

Nanocellulose constitutes promising resources for next-generation electronics, particularly when incorporated with conductive polymers due to their abundance, renewability, processability, biodegradability, flexibility, and mechanical performance. In this study, electrically conducting cellulose nanofibers were fabricated through in situ chemical polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) on the surface of sulfuric acid-treated cellulose nanofibers (SACN). The utilization of highly crystalline SACN extracted from tunicate yielded synergistic effects in PEDOT polymerization for achieving a highly conductive and molecularly uniform coating. Polymerization parameters, such as monomer concentration, molar ratio with oxidants, and temperature, were systematically investigated. High electrical conductivity of up to 57.8 S cm-1 was obtained without utilizing the classical polystyrenesulfonate dopant. The resulting nanocomposite demonstrates the unique advantages of both electrically conductive PEDOT and mechanically robust high-crystalline cellulose nanofibers. As a proof-of-applicational concept, an electrical circuit was drawn with SACN-PEDOT as the conductive ink on flexible paper using a simple commercial extrusion-based printer. Furthermore, the flame-retardant property of SACN-PEDOT was demonstrated owing to the high crystallinity of SACN, effective char formation, and high conductivity of PEDOT. The multifunctional SACN-PEDOT developed in this study shows great promise to be employed in versatile applications as a low-cost, ecofriendly, flexible, and sustainable electrically conductive material.

Biosignal Sensors and Deep Learning-Based Speech Recognition: A Review.

Voice is one of the essential mechanisms for communicating and expressing one's intentions as a human being. There are several causes of voice inability, including disease, accident, vocal abuse, medical surgery, ageing, and environmental pollution, and the risk of voice loss continues to increase. Novel approaches should have been developed for speech recognition and production because that would seriously undermine the quality of life and sometimes leads to isolation from society. In this review, we survey mouth interface technologies which are mouth-mounted devices for speech recognition, production, and volitional control, and the corresponding research to develop artificial mouth technologies based on various sensors, including electromyography (EMG), electroencephalography (EEG), electropalatography (EPG), electromagnetic articulography (EMA), permanent magnet articulography (PMA), gyros, images and 3-axial magnetic sensors, especially with deep learning techniques. We especially research various deep learning technologies related to voice recognition, including visual speech recognition, silent speech interface, and analyze its flow, and systematize them into a taxonomy. Finally, we discuss methods to solve the communication problems of people with disabilities in speaking and future research with respect to deep learning components.

Electrically conducting polymers for bio-interfacing electronics: From neural and cardiac interfaces to bone and artificial tissue biomaterials.

Conductive polymers (CPs) are gaining considerable attention as materials for implantable bioelectronics due to their unique features such as electronic-ionic hybrid conductivity, mechanical softness, ease of chemical modification, as well as moderate biocompatibility. CPs have been utilized for a wide range of applications including neural engineering, regenerative medicine, multi-functional sensors and actuators. This review focuses on CP materials design for use in bio-interfacing electronics including composites, conductive hydrogels, and electrochemical deposition. We start by elaborating on the fundamental materials characteristics of CPs, including bio-electrochemical charge-transfer mechanisms, and contrast them with naturally derived CPs. We then present recent critical examples of the bioelectronic and biomedical applications of CPs, including neural recording and stimulation, tissue regeneration, stretchable electronics, and mechanical actuation. We conclude with a perspective of the current material challenges of CPs in bio-interfacing electronics.

T1-Positive Mn2+-Doped Multi-Stimuli Responsive poly(L-DOPA) Nanoparticles for Photothermal and Photodynamic Combination Cancer Therapy.

In this study, we designed near-infrared (NIR)-responsive Mn2+-doped melanin-like poly(L-DOPA) nanoparticles (MNPs), which act as multifunctional nano-platforms for cancer therapy. MNPs, exhibited favorable π-π stacking, drug loading, dual stimuli (NIR and glutathione) responsive drug release, photothermal and photodynamic therapeutic activities, and T1-positive contrast for magnetic resonance imaging (MRI). First, MNPs were fabricated via KMnO4 oxidation, where the embedded Mn2+ acted as a T1-weighted contrast agent. MNPs were then modified using a photosensitizer, Pheophorbide A, via a reducible disulfide linker for glutathione-responsive intracellular release, and then loaded with doxorubicin through π-π stacking and hydrogen bonding. The therapeutic potential of MNPs was further explored via targeted design. MNPs were conjugated with folic acid (FA) and loaded with SN38, thereby demonstrating their ability to bind to different anti-cancer drugs and their potential as a versatile platform, integrating targeted cancer therapy and MRI-guided photothermal and chemotherapeutic therapy. The multimodal therapeutic functions of MNPs were investigated in terms of T1-MR contrast phantom study, photothermal and photodynamic activity, stimuli-responsive drug release, enhanced cellular uptake, and in vivo tumor ablation studies.

Controlled release of doxorubicin from polyethylene glycol functionalized melanin nanoparticles for breast cancer therapy: Part I. Production and drug release performance of the melanin nanoparticles.

In this study, polyethylene glycol (PEG) conjugated melanin nanoparticles (MNPs) were prepared (PEG-MNPs). A model chemotherapy drug, doxorubicin (DOX), was loaded into the PEG-MNPs with varied concentrations (0.125, 0.250, 0.500 mg/mL). TEM images showed that, DOX-PEG-MNPs are spherical-shaped and 15 ±â€¯2.2 nm in diameter. FTIR spectroscopy analysis demonstrated that MNPs were successfully modified with PEG. The UV-Vis spectroscopy results showed that the drug loading capacity of MNPs was 0.7 mg/ml of DOX in 2 mg/ml of PEG-MNPs. The time course data showed that, the release behavior of DOX from MNPs was primarily diffusion controlled. In vitro cytotoxicity assays demonstrated that MNP and PEG-MNP did not show any toxic effect on mouse fibroblast cells while DOX-PEG-MNP was able to inhibit the proliferation of human breast cancer cells. The results confirm that the application area of MNPs in controlled and prolonged drug release could be extended to the different types of cancer therapeutics.

A bioartificial rat heart tissue: Perfusion decellularization and characterization.

Despite remarkable advancement in the past decades, heart-related defects are still prone to progress irreversibly and can eventually lead to heart failure. A personalized extracellular matrix-based bioartificial heart created by allografts/xenografts emerges as an alternative as it can retain the original three-dimensional architecture combined with a preserved natural heart extracellular matrix. This study aimed at developing a procedure for decellularizing heart tissue harvested from rats and evaluating decellularization efficiency in terms of residual nuclear content and structural properties. Tissue sections showed no or little visible cell nuclei in decellularized heart, whereas the native heart showed dense cellularity. In addition, there was no significant variation in the alignment of muscle fibers upon decellularization. Furthermore, no significant difference was detected between native and decellularized hearts in terms of fiber diameter. Our findings demonstrate that fiber alignment and diameter can serve as additional parameters in the characterization of biological heart scaffolds as these provide valuable input for evaluating structural preservation of decellularized heart. The bioartificial scaffold formed here can be functionalized with patient's own material and utilized in regenerative engineering.