Recent advances in implantable sensors and electronics using printable materials for advanced healthcare.

This review article focuses on the recent printing technological progress in healthcare, underscoring the significant potential of implantable devices across diverse applications. Printing technologies have widespread use in developing health monitoring devices, diagnostic systems, and surgical devices. Recent years have witnessed remarkable progress in fabricating low-profile implantable devices, driven by advancements in printing technologies and nanomaterials. The importance of implantable biosensors and bioelectronics is highlighted, specifically exploring printing tools using bio-printable inks for practical applications, including a detailed examination of fabrication processes and essential parameters. This review also justifies the need for mechanical and electrical compatibility between bioelectronics and biological tissues. In addition to technological aspects, this article delves into the importance of appropriate packaging methods to enhance implantable devices' performance, compatibility, and longevity, which are made possible by integrating cutting-edge printing technology. Collectively, we aim to shed light on the holistic landscape of implantable biosensors and bioelectronics, showcasing their evolving role in advancing healthcare through innovative printing technologies.

Aliovalent Substitution Tunes Physical Properties in a Conductive Bis(dithiolene) Two-Dimensional Metal-Organic Framework.

Two-dimensional conductive metal-organic frameworks have emerged as promising electronic materials for applications in (opto)electronic, thermoelectric, magnetic, electrocatalytic, and energy storage devices. Many bottom-up or postsynthetic protocols have been developed to isolate these materials or further modulate their electronic properties. However, some methodologies commonly used in classic semiconductors, notably, aliovalent substitution, are conspicuously absent. Here, we demonstrate how aliovalent Fe(III) to Ni(II) substitution enables the isolation of a Ni bis(dithiolene) material from a previously reported Fe analogue. Detailed characterization supports the idea that aliovalent substitution of Fe(III) to Ni(II) results in an in situ oxidation of the organic dithiolene linker. This substitution-induced redox tuning modulates the electronic properties in the system, leading to higher electrical conductivity and Hall mobility but slightly lower carrier densities and weaker antiferromagnetic interactions. Moreover, this aliovalent substitution improves the material's electrochemical stability and thus enables pseudocapacitive behavior in the Ni material. These results demonstrate how classic aliovalent substitution strategies in semiconductors can also be leveraged in conductive MOFs and add further support to this class of compounds as emerging electronic materials.

A study of the antibacterial mechanism of pinocembrin against multidrug-resistant Aeromonas hydrophila / Un estudio del mecanismo antibacteriano de la pinocembrina contra Aeromonas hydrophila resistente a múltiples fármacos

Aeromonas hydrophila is a common pathogen in fish that has caused severe economic losses in aquaculture worldwide. With the emergence of bacterial resistance, it is necessary to develop new drugs to combat bacterial infection, particularly for multidrug-resistant bacteria. In this study, the antibacterial activity of pinocembrin was investigated by observing bacterial growth and microscopic structure, and its mechanism of action was identified by investigating its effect on protein and DNA. The antibacterial susceptibility test indicated that pinocembrin inhibits A. hydrophila growth. The minimal inhibitory concentration and minimum bactericidal concentration were 256 μg/mL and 512 μg/mL, respectively. Ultrastructurally, the bacteria treated with pinocembrin showed surface roughness and plasmolysis. When bacteria were treated with 512 μg/mL pinocembrin, lactate dehydrogenase activity and soluble protein content decreased significantly, and electrical conductivity and DNA exosmosis levels increased by 4.21 ± 0.64% and 15.98 ± 1.93 mg/L, respectively. Staining with 4′, 6-Diamidino-2-phenylindole showed that the nucleic acid fluorescence intensity and density decreased after the treatment with pinocembrin. Pinocembrin may inhibit the growth of A. hydrophila by increasing cell membrane permeability and affecting protein and DNA metabolism. Thus, pinocembrin is a candidate drug for the treatment of A. hydrophila infection in aquaculture.(AU)

Photo-responsive hydrogel-based re-programmable metamaterials.

This paper explores a novel programmable metamaterial using stimuli-responsive hydrogels with a demonstration of bandgap formation and tuning. Specifically, a photo-responsive hydrogel beam that can achieve re-programmable periodicity in geometric and material properties through patterned light irradiation is designed. Hydrogels consist of polymeric networks and water molecules. Many unique properties of hydrogels, including bio-compatibility, stimuli-responsiveness, and low dissipation make them ideal for enabling re-programmable metamaterials for manipulating structural dynamic response and wave propagation characteristics. Bandgap generation and tunability in photo-responsive hydrogel-based metamaterial (in the form of a diatomic phononic chain) as well as the effects of system parameters such as light exposure pattern and photo-sensitive group concentration on the bandgap width and center frequency are systematically studied. In agreement with finite-element model simulations, it is observed that an increase in light exposure region size reduces both the bandgap width and center frequency, while an increase in the concentration of photo-sensitive group increases bandgap width, attenuation and reduces its center frequency. This work unveils the potential of stimuli-response hydrogels as a new class of low-loss soft metamaterials, unlike most other soft materials that are too lossy to sustain and exploit wave phenomena.

Protective effect of cinnamaldehyde on channel catfish infected by drug-resistant Aeromonas hydrophila.

The protective effect of cinnamaldehyde on channel catfish infected by drug-resistant Aeromonas hydrophila CW strain was explored by observing the clinical signs and histopathology, measuring the cumulative mortality, serum biochemical and non-specific immune indicators, and intestinal microbiota in this study. The cumulative survival rate of the cinnamaldehyde within 14 days was significantly higher than that of the challenge group, which was 70% and 20%, respectively. Compared with the challenge group, the activities of lysozyme, superoxide dismutase, and glutathione peroxidase in the treatment group were increased, while there was no significant difference in catalase activity. Compared with the challenge group, the histopathology results showed that the injury of liver, spleen, and kidney was significantly alleviated after cinnamaldehyde treatment. The results of intestinal microbiota showed that the proportion of Proteobacteria in the challenge group was significantly increased, and the proportion of Aeromonas sp. reached 30% based on the analysis of species classification level. The composition of dominant species in the treatment group was similar to the control group. In conclusion, cinnamaldehyde increased the cumulative survival rate of channel catfish infected by A. hydrophila. It could protect channel catfish through improving the non-specific immune function of channel catfish, alleviating the pathological lesions of liver, spleen, kidney, and intestine, and maintaining the relative balance of the intestinal microbiota. Therefore, cinnamaldehyde could be a candidate drug for the treatment of A. hydrophila infection.

A study of the antibacterial mechanism of pinocembrin against multidrug-resistant Aeromonas hydrophila.

Aeromonas hydrophila is a common pathogen in fish that has caused severe economic losses in aquaculture worldwide. With the emergence of bacterial resistance, it is necessary to develop new drugs to combat bacterial infection, particularly for multidrug-resistant bacteria. In this study, the antibacterial activity of pinocembrin was investigated by observing bacterial growth and microscopic structure, and its mechanism of action was identified by investigating its effect on protein and DNA. The antibacterial susceptibility test indicated that pinocembrin inhibits A. hydrophila growth. The minimal inhibitory concentration and minimum bactericidal concentration were 256 µg/mL and 512 µg/mL, respectively. Ultrastructurally, the bacteria treated with pinocembrin showed surface roughness and plasmolysis. When bacteria were treated with 512 µg/mL pinocembrin, lactate dehydrogenase activity and soluble protein content decreased significantly, and electrical conductivity and DNA exosmosis levels increased by 4.21 ± 0.64% and 15.98 ± 1.93 mg/L, respectively. Staining with 4', 6-Diamidino-2-phenylindole showed that the nucleic acid fluorescence intensity and density decreased after the treatment with pinocembrin. Pinocembrin may inhibit the growth of A. hydrophila by increasing cell membrane permeability and affecting protein and DNA metabolism. Thus, pinocembrin is a candidate drug for the treatment of A. hydrophila infection in aquaculture.

3D Printing of Biocompatible Shape-Memory Double Network Hydrogels.

Shape-memory hydrogels can be fixed to an arbitrary temporary shape and recover their permanent shape under appropriate stimulus conditions. Their shape-memory behavior and biocompatible mechanical and chemical properties impart them with many biomedical applications. However, like most hydrogels, traditional shape-memory hydrogels suffer from intrinsic brittleness due to the network inhomogeneity and high water content. In the past, the double network (DN) scheme has been proved a robust method to improve the mechanical performance of hydrogels. Although 3D printing of DN hydrogels has been realized before, 3D printable shape-memory DN hydrogels have not been achieved so far. In this work, we propose a one-pot method for printing a biocompatible shape-memory DN hydrogel via fused deposition method. The two networks incorporated to the hydrogel ink are polyacrylamide (PAAm) and gelatin. The PAAm network is covalently cross-linked and responsible for the permanent shape, while the gelatin network has thermoreversible cross-links and responsible for fixing the temporary shape. The DN hydrogel shows 3 to 7 times higher fracture toughness than a single network gelatin or PAAm hydrogel and can be fixed to 300% of its original length under tension and 10% of its original thickness under compression. The ink compositions are tuned for optimal printing quality and shape-memory performance. The robust mechanical integrity and dramatic shape transformation capability of the 3D-printed shape-memory DN hydrogel will open-up new potential applications in transformative medical robots and self-deployable devices.

Enhanced Condensation on Liquid-Infused Nanoporous Surfaces by Vibration-Assisted Droplet Sweeping.

Condensation is a universal phenomenon that occurs in nature and industry. Previous studies have used superhydrophobicity and liquid infusion to enable superior liquid repellency due to reduced contact angle hysteresis. However, small condensate droplets remain immobile on condensing surfaces until they grow to the departing size at which the body force can overcome the contact line pinning force. Hence, condensation heat transfer is limited by these remaining droplets that act as thermal barriers. To break these limitations, we introduce vibrational actuation to a slippery liquid-infused nanoporous surface (SLIPS) and show enhanced droplet mobility, controllable condensate repellency, and more efficient heat transfer compared to static SLIPSs. We demonstrate 39% smaller departing droplet size and 8× faster droplet departing speeds on the dynamic vibrating SLIPS compared to the nonactuated SLIPS. To understand the implications of these behaviors on heat transfer, we investigate the condensate area coverage and droplet distribution to verify enhanced dewetting on dynamic vibrating SLIPSs. Using well-validated heat transfer models, we demonstrate enhanced condensation heat transfer on dynamic SLIPSs due to the higher population of smaller condensate droplets (<100 µm). In addition to condensation heat transfer, we also show that vibrating SLIPSs can enhance droplet collection. This work utilizes the synergistic combination of surface chemistry and mechanical actuation to realize enhanced droplet mobility and heat transfer in an electrically controllable and switchable manner.

A Photoresponsive Hydrogel with Enhanced Photoefficiency and the Decoupled Process of Light Activation and Shape Changing for Precise Geometric Control.

Traditional shape-morphing hydrogels rely on structural implementation of inhomogeneity inside the material during fabrication to realize predetermined complex shape change upon activation. In recent years, several systems with reprogrammable shape-morphing capabilities have been developed. Among those, the photoresponsive hydrogels offer the best spatial and temporal control. However, for most photoresponsive hydrogels, upon light irradiation, they simultaneously deform, which requires the projection of the light pattern to be continuously adaptive to the deforming gel. It is impractical for complex 3D morphing. In this paper, by incorporating two photodissociable molecules that can form a reactive ion couple upon light activation into one hydrogel, the light irradiation process is decoupled with the morphing process, and the consumption of the reactive ion couple drives the reversible photochemical reaction forward. Consequently, the photochemical reaction efficiency is improved, and the photoresponsive molecules are locked in the activated state until a recovery stimulus is applied. Based on the proposed general scheme, a specific example is given by incorporating the triphenylmethane leucohydroxide and 2-nitrobenzaldehyde molecules into a polyacrylamide hydrogel. The swelling behavior is characterized, and the reprogrammable morphing with precisely controlled geometry is demonstrated.

Study the antibacterial mechanism of cinnamaldehyde against drug-resistant Aeromonas hydrophila in vitro.

Aeromonas hydrophila, a highly infectious pathogen, causes several infections in aquatic animals and huge economic losses. Antibiotics are often used to treat A. hydrophila infections. However, overuse and irrational usage of antibiotics has led to severe antibiotic residues and emergence of resistance. There is therefore an urgent need for a new sustainable drug to control bacterial infection. Cinnamaldehyde, a plant-derived ingredient, has been found to have good antibacterial activity against A. hydrophila in vitro, but its mechanism of action remains unknown. In this study, we investigated the mechanism of cinnamaldehyde against A. hydrophila by evaluating the effects of cinnamaldehyde on A. hydrophila cell growth, cell morphology, electrical conductivity, lactate dehydrogenase (LDH), protein metabolism and DNA. The minimal inhibitory concentration and minimum bactericidal concentration of cinnamaldehyde were 256 and 512 µg/mL, respectively. Microscopy results showed disrupted cell wall and membrane, loss of cytoplasm, interior cavitation and unusual binary fission in the cinnamaldehyde-treated group. Electrical conductivity, LDH activity content and DNA extravasation in cinnamaldehyde-treated A. hydrophila increased by 7.14%, 16.75% and 20.29 µg/mL, respectively. Furthermore, nucleic acid fluorescence intensity and density decreased over time in the cinnamaldehyde-treated group. Taken together, these findings suggest that cinnamaldehyde can inhibit the growth of A. hydrophila by disrupting cell membranes and affecting protein metabolism.

Enhanced removal of vanadium(V) from groundwater by layered double hydroxide-supported nanoscale zerovalent iron.

To reduce the toxicity of vanadium(V) [V(V)] and inhibit the desorption of adsorbed vanadium in groundwater, we synthesized nanoscale zerovalent iron (nZVI) dispersed on layered double hydroxide (LDH) composites (nZVI@LDH) to remove V(V) from simulated groundwater. We found that nZVI@LDH could reduce high-valence vanadium to low-valence vanadium, then forming vanadium-containing precipitation to reduce the toxicity and inhibiting vanadium from returning to groundwater. SEM and XRD characterizations exhibited the uniform dispersal of nZVI on the surface of LDH. nZVI@LDH with nZVI/LDH at a mass ratio of 1:2 provided the maximum adsorption capacity of 93.7 mg g-1 at pH 3.0. Coexisting anions and dissolved oxygen in groundwater have little effect on V(V) removal. nZVI@LDH performed well across a wide pH range (3.0-8.0). The surface characterizations and XPS analysis revealed that LDH as supporting materials inhibited the aggregation and passivation of nZVI. The adsorbed V(V) was reduced to V(IV) and V(III) by nZVI and spontaneously transformed into insoluble VO2 and V2O3. The DFT calculations indicated the strong complexation and better stability of the V(IV) and V(III) species with nZVI@LDH than V(V). This work suggests that nZVI@LDH has the potential to serve as an efficient material for the immobilization of V(V) in groundwater.

Discovery of LY3325656: A GPR142 agonist suitable for clinical testing in human.

The discovery and optimization of a novel series of GPR142 agonists are described. These led to the identification of compound 21 (LY3325656), which demonstrated anti-diabetic benefits in pre-clinical studies and ADME/PK properties suitable for human dosing. Compound 21 is the first GPR142 agonist molecule advancing to phase 1 clinic trials for the treatment of Type 2 diabetes.

Adhesive mechanism of different Salmonella fimbrial adhesins.

Salmonellosis is a serious threat to human and animal health. Salmonella adhesion to the host cell is an initial and most crucial step in the pathogenesis of salmonellosis. Many factors are involved in the adhesion process of Salmonella infection. Fimbriae are one of the most important factors in the adhesion of Salmonella. The Salmonella fimbriae are assembled in three types of assembly pathways: chaperon-usher, nucleation-precipitation, and type IV fimbriae. These assembly pathways lead to multiple types of fimbriae. Salmonella fimbriae bind to host cell receptors to initiate adhesion. So far, many receptors have been identified, such as Toll-like receptors. However, several receptors that may be involved in the adhesive mechanism of Salmonella fimbriae are still un-identified. This review aimed to summarize the types of Salmonella fimbriae produced by different assembly pathways and their role in adhesion. It also enlisted previously discovered receptors involved in adhesion. This review might help readers to develop a comprehensive understanding of Salmonella fimbriae, their role in adhesion, and recently developed strategies to counter Salmonella infection.

Engineering Antifouling Conducting Polymers for Modern Biomedical Applications.

Conducting polymers are considered to be favorable electrode materials for implanted biosensors and bioelectronics, because their mechanical properties are similar to those of biological tissues such as nerve and brain tissues. However, one of the primary challenges for implanted devices is to prevent the unwanted protein adhesion or cell binding within biological fluids. The nonspecific adsorption generally causes the malfunction of implanted devices, which is problematic for long-term applications. When responding to the requirements of solving the problems caused by nonspecific adsorption, an increasing number of studies on antifouling conducting polymers has been recently published. In this review, synthetic strategies for preparing antifouling conducting polymers, including direct synthesis of functional monomers and post-functionalization, are introduced. The applications of antifouling conducting polymers in modern biomedical applications are particularly highlighted. This paper presents focuses on the features of antifouling conducting polymers and the challenges of modern biomedical applications.

Critical Study of the Recognition between C-Reactive Protein and Surface-Immobilized Phosphorylcholine by Quartz Crystal Microbalance with Dissipation.

C-reactive protein (CRP), a biomarker for cardiovascular disease, has been reported to have a strong affinity to zwitterionic phosphorylcholine (PC) groups in the presence of calcium ions. In addition, PC-immobilized surfaces have been used as a nonfouling coating to prevent nonspecific protein binding. By appropriately using the features of PC-immobilized surfaces, including specific recognition to CRP and nonfouling surface, it is reasonable to create an antibody-free biosensor for the specific capture of CRP. In this study, PC-functionalized 3,4-ethylenedioxythiophene (EDOT) monomers were used to prepare PC-immobilized surfaces. The density of PC groups on the surface can be fine-tuned by changing the composition of the monomer solutions for the electropolymerization. The density of PC group was confirmed by X-ray photoelectron spectroscopy (XPS). The specific interaction of CRP with PC groups was monitored by using a quartz crystal microbalance with dissipation (QCM-D). The amount of protein binding could be estimated by the reduction in frequency readout. Through the QCM-D measurement, we revealed the nonfouling property and the specific CRP capture from our PC-immobilized surfaces. Notably, the dissipation energy also dropped during the binding process between CRP and PC, indicating the release of water molecules from the PC groups during CRP adsorption. We anticipate that surface-bound water molecules are mainly released from areas near the immobilized PC groups. Based on Hofmeister series, we further examined the influence of ions by introducing four different anions including both kosmotrope (order maker) and chaotrope (disorder maker) into the buffer for the CRP binding test. The results showed that the concentration and the type of anions play an important role in CRP binding. The present fundamental study reveals deep insights into the recognition between CRP and surface-immobilized PC groups, which can facilitate the development of CRP sensing platforms.

A New Approach for Mobile Advertising Click-Through Rate Estimation Based on Deep Belief Nets.

In recent years, with the rapid development of mobile Internet and its business applications, mobile advertising Click-Through Rate (CTR) estimation has become a hot research direction in the field of computational advertising, which is used to achieve accurate advertisement delivery for the best benefits in the three-side game between media, advertisers, and audiences. Current research on the estimation of CTR mainly uses the methods and models of machine learning, such as linear model or recommendation algorithms. However, most of these methods are insufficient to extract the data features and cannot reflect the nonlinear relationship between different features. In order to solve these problems, we propose a new model based on Deep Belief Nets to predict the CTR of mobile advertising, which combines together the powerful data representation and feature extraction capability of Deep Belief Nets, with the advantage of simplicity of traditional Logistic Regression models. Based on the training dataset with the information of over 40 million mobile advertisements during a period of 10 days, our experiments show that our new model has better estimation accuracy than the classic Logistic Regression (LR) model by 5.57% and Support Vector Regression (SVR) model by 5.80%.

Total synthesis of phorboxazole A via de novo oxazole formation: strategy and component assembly.

The phorboxazole natural products are among the most potent inhibitors of cancer cell division, but they are essentially unavailable from natural sources at present. Laboratory syntheses based upon tri-component fragment coupling strategies have been developed that provide phorboxazole A and analogues in a reliable manner and with unprecedented efficiency. This has been orchestrated to occur via the sequential or simultaneous formation of both of the natural product's oxazole moieties from two serine-derived amides, involving oxidation-cyclodehydrations. The optimized preparation of three pre-assembled components, representing carbons 3-17, 18-30, and 31-46, has been developed. This article details the design and syntheses of these three essential building blocks. The convergent coupling approach is designed to facilitate the incorporation of structural changes within each component to generate unnatural analogues, targeting those with enhanced therapeutic potential and efficacy.

A potentially valuable advance in the synthesis of carbohydrate-based anticancer vaccines through extended cycloaddition chemistry.

An advance in the long-term problem of joining complex oligosaccharides to polypeptides and even proteins is described herein. The key method involves equipping the oligosaccharide sector with an azide and the polypeptide with pendant alkynyl functionality. The two sectors are joined through a "click-like" cycloaddition. The method encompasses oligosaccharide constructs with several azide linkages which undergo concurrent cycloaddition to peptide-based acetylenes. This technology could well prove to be useful in the construction of fully synthetic vaccines.

Studies related to the relative thermodynamic stability of C-terminal peptidyl esters of O-hydroxy thiophenol: emergence of a doable strategy for non-cysteine ligation applicable to the chemical synthesis of glycopeptides.

A pathway has been devised, wherein a phenolic ester of a C-terminal peptide is ligated with an N-terminal peptide through two consecutive acyl migrations. In the first transacylation, the C-terminus is transferred from a phenol to a newly liberated ortho-thiol function. Subsequently, the acyl group is transported to a proximal benzylamine through a six-membered transition state.