Electrochemical monitoring of levofloxacin using a silver nanoparticle-modified disposable device based on a lab-made conductive ink.

The emergence of bacteria genetically resistant to first- and second-generation fluoroquinolones has resulted in increased consumption of levofloxacin (LEV) in human and veterinary medicine. In this regard, the development of low cost and good sensitivity electrochemical devices has been highly required. Thus, in this work, we propose the development of a disposable electrochemical device (DED) using a lab-made conductive ink based on graphite powder and nail polish immobilized on a rigid polyvinyl chloride support (transparent sheet). Additionally, a simple and quick protocol for the electrodeposition of silver nanoparticles was used in order to improve the electroanalytical performance of the sensor (2.75-fold). A differential pulse voltammetry (DPV) method was optimized and the sensor was applied for LEV monitoring in pharmaceutical formulation samples, synthetic urine and simulated body fluid. The method showed a wide linear working range ranging from 0.5 to 50 µmol L-1 and a detection limit of 68.3 nmol L-1. Furthermore, the precision was adequate (RSD < 4.7%), while the accuracy was evaluated through spiked samples with percent recovery ranging from 93 to 103%. The sensor was also shown to be selective for LEV against other electroactive antibiotic species, thus demonstrating suitable characteristics for electroanalytical applications.

Conductive Ink-Coated Paper-Based Supersandwich DNA Biosensor for Ultrasensitive Detection of Neisseria gonorrhoeae.

Herein, we report results of the studies relating to the development of an impedimetric, magnetic bead-assisted supersandwich DNA hybridization assay for ultrasensitive detection of Neisseria gonorrhoeae, the causative agent of a sexually transmitted infection (STI), gonorrhea. First, a conductive ink was formulated by homogenously dispersing carboxylated multiwalled carbon nanotubes (cMWCNTs) in a stable emulsion of terpineol and an aqueous suspension of carboxymethyl cellulose (CMC). The ink, labeled C5, was coated onto paper substrates to fabricate C5@paper conductive electrodes. Thereafter, a magnetic bead (MB)-assisted supersandwich DNA hybridization assay was optimized against the porA pseudogene of N. gonorrhoeae. For this purpose, a pair of specific 5' aminated capture probes (SCP) and supersandwich detector probes (SDP) was designed, which allowed the enrichment of target gonorrheal DNA sequence from a milieu of substances. The SD probe was designed such that instead of 1:1 binding, it allowed the binding of more than one T strand, leading to a 'ladder-like' DNA supersandwich structure. The MB-assisted supersandwich assay was integrated into the C5@paper electrodes for electrochemical analysis. The C5@paper electrodes were found to be highly conductive by a four-probe conductivity method (maximum conductivity of 10.1 S·cm-1). Further, the biosensing assay displayed a wide linear range of 100 aM-100 nM (109 orders of magnitude) with an excellent sensitivity of 22.6 kΩ·(log[concentration])-1. The clinical applicability of the biosensing assay was assessed by detecting genomic DNA extracted from N. gonorrhoeae in the presence of DNA from different non-gonorrheal bacterial species. In conclusion, this study demonstrates a highly sensitive, cost-effective, and label-free paper-based device for STI diagnostics. The ink formulation prepared for the study was found to be highly thixotropic, which indicates that the paper electrodes can be screen-printed in a reproducible and scalable manner.

All-printed multiplexed electrocatalytic biosensors with rationally designed nanoparticle inks.

Inkjet printing, capable of rapid and template-free fabrication with high resolution and low material waste, is a promising method to construct electrochemical biosensor devices. However, the construction of fully inkjet-printed electrochemical biosensor remains a challenge owing to the lack of appropriate inks, especially the sensing inks of bioactive materials. Herein, we demonstrate a fully inkjet-printed, integrated and multiplexed electrochemical biosensor by combining rationally designed nanoparticle Inks. The stable gold (Au) nanoparticles ink with lower sintering temperature is prepared by using L-cysteine as stabilizer, and it is used to print the interconnects, the counter electrodes, and the working electrodes. The SU-8 ink is used to serve as dielectric layer for the biosensor, whereas the silver electrode is printed on the Au electrode by using commercially silver nanoparticles ink before it is chlorinated to prepare Ag/AgCl reference electrode. Moreover, we synthesize an inkjet-printable and electroactive ink, by the 'one-pot method', which is composed of conductive poly 6-aminoindole (PIn-6-NH2) and gold-palladium (Au-Pd) alloy nanoparticle (Au-Pd@PIn-6-NH2) to enhance the sensing performance of gold electrode towards hydrogen peroxide (H2O2). Especially, the amino groups in PIn-6-NH2can be further used to immobilizing glucose oxidase (GOx) and lactic acid oxidase (LOx) by glutaraldehyde to prepare printable sensing ink for the detection of glucose and lactate. The fully inkjet-printed electrochemical biosensor enabled by advanced inks can simultaneously detect glucose and lactate with good sensitivity and selectivity, as well as facile and scalable fabrication, showing great promise for metabolic monitoring.

Transfer rates of Salmonella Typhimurium, Listeria monocytogenes, and a human norovirus surrogate impacted by macronutrient composition of food inks in 3D food printing systems.

3D food printers (3DFPs) allow for the customization of the physiochemical properties of foods in new ways. Transfer kinetics of foodborne pathogens between surfaces and food inks have not been evaluated in 3DFPs. This study aimed to determine if the macromolecular composition of food inks would impact the transfer rate of foodborne pathogens from the stainless steel food ink capsule to the 3D printed food. Salmonella Typhimurium, Listeria monocytogenes, and a human norovirus surrogate, Tulane virus (TuV), were inoculated onto the interior surface of stainless steel food ink capsules and dried for 30 min. Subsequently, 100 g of one of the following prepared food inks was extruded: (1) pure butter, (2) a powdered sugar solution, (3) a protein powder solution, and (4) a 1:1:1 ratio of all three macromolecules. Pathogen enumeration was completed for both the soiled capsules and the printed food products and resulting transfer rates were estimated using a generalized linear model with quasibinomial errors. A significant two-way interaction effect was found between microorganism type and food ink type (P = 0.0002). Tulane virus was typically transferred the most, and no significant differences between L. monocytogenes and S. Typhimurium were observed for any food matrix or across food matrices. Among food matrices, the complex mixture transferred fewer microorganisms in all instances, while butter, protein, and sugar were all statistically indistinguishable. This research seeks to further develop the field of 3DFP safety and to advance the understanding of the role of macromolecular composition in pathogen transfer kinetics, which have not previously been explored in pure matrices.

High resolution and fidelity 3D printing of Laponite and alginate ink hydrogels for tunable biomedical applications.

The formulation of hydrogels that meet the necessary flow characteristics for their extrusion-based 3D printing while providing good printability, resolution, accuracy and stability, requires long development processes. This work presents the technological development of a hydrogel-based ink of Laponite and alginate and evaluates its printing capacity. As a novelty, this article reports a standardizable protocol to quantitatively define the best printing parameters for the development of novel inks, providing new printability evaluation parameters such as the Printing Accuracy Escalation Index. As a result, this research develops a printable Laponite-Alginate hydrogel that presents printability characteristics. This ink is employed for the reproducible manufacture of 3D printed scaffolds with versatile and complex straight or curved printing patterns for a better adaptation to different final applications. Obtained constructs prove to be stable over time thanks to the optimization of a curing process. In addition, the study of the swelling and degradation behavior of the Laponite and alginate 3D printed scaffolds in different culture media allows the prediction of their behavior in future in vitro or in vivo developments. Finally, this study demonstrates the absence of cytotoxicity of the printed formulations, hence, setting the stage for their use in the field of biomedicine.

Insights into Common Octopus (Octopus vulgaris) Ink Proteome and Bioactive Peptides Using Proteomic Approaches.

The common octopus (Octopus vulgaris) is nowadays the most demanded cephalopod species for human consumption. This species was also postulated for aquaculture diversification to supply its increasing demand in the market worldwide, which only relies on continuously declining field captures. In addition, they serve as model species for biomedical and behavioral studies. Body parts of marine species are usually removed before reaching the final consumer as by-products in order to improve preservation, reduce shipping weight, and increase product quality. These by-products have recently attracted increasing attention due to the discovery of several relevant bioactive compounds. Particularly, the common octopus ink has been described as having antimicrobial and antioxidant properties, among others. In this study, the advanced proteomics discipline was applied to generate a common octopus reference proteome to screen potential bioactive peptides from fishing discards and by-products such as ink. A shotgun proteomics approach by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) using an Orbitrap Elite instrument was used to create a reference dataset from octopus ink. A total of 1432 different peptides belonging to 361 non-redundant annotated proteins were identified. The final proteome compilation was investigated by integrated in silico studies, including gene ontology (GO) term enrichment, pathways, and network studies. Different immune functioning proteins involved in the innate immune system, such as ferritin, catalase, proteasome, Cu/Zn superoxide dismutase, calreticulin, disulfide isomerase, heat shock protein, etc., were found in ink protein networks. Additionally, the potential of bioactive peptides from octopus ink was addressed. These bioactive peptides can exert beneficial health properties such as antimicrobial, antioxidant, antihypertensive, and antitumoral properties and are therefore considered lead compounds for developing pharmacological, functional foods or nutraceuticals.

A closer look at the Azzolino collection.

The state of preservation of documents from the historically significant Azzolino collection at the Swedish National Archives has been investigated and analyses carried out of the iron gall inks. The collection shows varied levels of iron gall ink corrosion. An initial visual condition survey was followed by characterisation of the writing ink with XRF spectrometry on a selection of documents. The aim was to investigate whether ink composition could be related to author or geography, and in turn to level of ink corrosion, which could then serve as a basis for decisions on treatment options. Results indicate a relative purity of the inks in this collection in terms of high iron content and low levels of other elements, entailing that elemental analysis is not a good tool to predict potential deterioration of ink in single documents from this historical context. XRF-mapping showed a possibility for discerning authors by ink composition, contributing meaningful information to questions of attribution and historical context for these documents. A tendency for the ink of Queen Christina to contain more copper than inks from the other authors, and the indication that some inks contain calcium, may be of note for further study.

Sustainable 3D printing of oral films with tunable characteristics using CMC-based inks from durian rind wastes.

With the growing interest in environmentally friendly and personalized medicines, new concept for combining three-dimensional printing (3DP) with natural-based biomaterials derived from agro-food wastes has emerged. This approach provides sustainable solutions for agricultural waste management and potential for developing of novel pharmaceutical products with tunable characteristics. This work demonstrated the feasibility of fabricating personalized theophylline films with four different structures (Full, Grid, Star, and Hilbert) using syringe extrusion 3DP and carboxymethyl cellulose (CMC) derived from durian rind wastes. Our findings suggested that all the CMC-based inks with shear thinning properties capable of being extruded smoothly through a small nozzle could potentially be used to fabricate the films with various complex printing patterns and high structural fidelity. The results also demonstrated that the film characteristics and release profiles could be easily modified by simply changing the slicing parameters (e.g., infill density and printing pattern). Amongst all formulations, Grid film, which was 3D-printed with 40 % infill and a grid pattern, demonstrated a highly porous structure with high total pore volume. The voids between printing layers in Grid film increased theophylline release (up to 90 % in 45 min) through improved wetting and water penetration. All findings in this study provide significant insight into how to modify film characteristics simply by digitally changing the printing pattern in slicer software without creating a new CAD model. This approach could help to simplify the 3DP process so that non-specialist users can easily implement it in community pharmacies or hospital on demand.

Current advancements in bio-ink technology for cartilage and bone tissue engineering.

In tissue engineering, the fate of a particular organ/tissue regeneration and repair mainly depends on three pillars - 3D architecture, cells used, and stimulus provided. 3D cell supportive structure development is one of the crucial pillars necessary for defining organ/tissue geometry and shape. In recent years, the advancements in 3D bio-printing (additive manufacturing) made it possible to develop very precise 3D architectures with the help of industrial software like Computer-Aided Design (CAD). The main requirement for the 3D printing process is the bio-ink, which can act as a source for cell support, proliferation, drug (growth factors, stimulators) delivery, and organ/tissue shape. The selection of the bio-ink depends upon the type of 3D tissue of interest. Printing tissues like bone and cartilage is always challenging because it is difficult to find printable biomaterial that can act as bio-ink and mimic the strength of the natural bone and cartilage tissues. This review describes different biomaterials used to develop bio-inks with different processing variables and cell-seeding densities for bone and cartilage 3D printing applications. The review also discusses the advantages, limitations, and cell bio-ink compatibility in each biomaterial section. The emphasis is given to bio-inks reported for 3D printing cartilage and bone and their applications in orthopedics and orthodontists. The critical/important performance and the architectural morphology requirements of desired bone and cartilage bio-inks were compiled in summary.

Study on the preparation and biological activities of low molecular weight squid ink polysaccharide from Sepiella maindroni.

Sepiella maindroni ink polysaccharide (SIP) from the ink of cuttlefish Sepiella maindroni and its sulfated derivative (SIP-SII) have been demonstrated to possess diverse biological activities. But little is known about low molecular weight squid ink polysaccharides (LMWSIPs). In this study, LMWSIPs were prepared by acidolysis, and the fragments with molecular weight (Mw) distribution in the ranges of 7 kDa to 9 kDa, 5 kDa to 7 kDa and 3 kDa to 5 kDa were grouped and named as LMWSIP-1, LMWSIP-2 and LMWSIP-3, respectively. The structural features of LMWSIPs were elucidated, and their anti-tumor, antioxidant and immunomodulatory activities were also studied. The results showed that with the exception of LMWSIP-3, the main structures of LMWSIP-1 and LMWSIP-2 did not change compared with SIP. Though there were no significant differences in the antioxidant capacity between LMWSIPs and SIP, the anti-tumor and immunomodulatory activities of SIP were enhanced to a certain extent after degradation. It is particularly noteworthy that the activities of LMWSIP-2 in anti-proliferation, promoting apoptosis and inhibiting migration of tumor cells as well as promoting the proliferation of spleen lymphocytes were significantly higher than those of SIP and the other degradation products, which is promising in the anti-tumor pharmaceutical field.

Engineering natural based nanocomposite inks via interface interaction for extrusion 3D printing.

Nanocomposites and low-viscous materials lack translation in additive manufacturing technologies due to deficiency in rheological requirements and heterogeneity of their preparation. This work proposes the chemical crosslinking between composing phases as a universal approach for mitigating such issues. The model system is composed of amine-functionalized bioactive glass nanoparticles (BGNP) and light-responsive methacrylated bovine serum albumin (BSAMA) which further allows post-print photocrosslinking. The interfacial interaction was conducted by 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide crosslinking agent and N-Hydroxysuccinimide between BGNP-grafted amines and BSAMA's carboxylic groups. Different chemical crosslinking amounts and percentages of BGNP in the nanocomposites were tested. The improved interface interactions increased the elastic and viscous modulus of all formulations. More pronounced increases were found with the highest crosslinking agent amounts (4 % w/v) and BGNP concentrations (10 % w/w). This formulation also displayed the highest Young's modulus of the double-crosslinked construct. All composite formulations could effectively immobilize the BGNP and turn an extremely low viscous material into an appropriate inks for 3d printing technologies, attesting for the systems' tunability. Thus, we describe a versatile methodology which can successfully render tunable and light-responsive nanocomposite inks with homogeneously distributed bioactive fillers. This system can further reproducibly recapitulate phases of other natures, broadening applicability.

The current state of the art in gellan-based printing inks in tissue engineering.

With the advancement of enhanced fabrication technologies, specifically 3D printing, it is now possible to build artificial tissue for personalized healing. However, inks developed from polymers often fail to meet expectations in terms of mechanical strength, scaffold integrity, and the stimulation of tissue formation. Developing new printable formulations as well as adapting existing printing methods is an essential aspect of contemporary biofabrication research. In order to push the boundaries of the printability window, various strategies have been developed employing gellan gum. This has resulted in major breakthroughs in the development of 3D hydrogels scaffolds that exhibit significant resemblance to genuine tissues and enables the fabrication of more complex systems. In light of the many uses of gellan gum, the purpose of this paper is to provide a synopsis of the printable ink designs drawing attention to the various compositions and fabrication approaches that may be used for tuning the properties of 3D printed hydrogels for tissue engineering applications. The purpose of this article is to outline the development of gellan-based 3D printing inks and to encourage research by highlighting the possible applications of gellan gum.

Structure, Functionality, Compatibility with Pesticides and Beneficial Microbes, and Potential Applications of a New Delivery System Based on Ink-Jet Technology.

Accurate application of agrochemicals is an important way to achieve efficient use of chemicals and to combine limited pollution with effective control of weeds, pests, and diseases. In this context, we investigate the potential application of a new delivery system based on ink-jet technology. First, we describe the structure and functionality of ink-jet technology for agrochemical delivery. We then evaluate the compatibility of ink-jet technology with a range of pesticides (four herbicides, eight fungicides, and eight insecticides) and beneficial microbes, including fungi and bacteria. Finally, we investigated the feasibility of using ink-jet technology in a microgreens production system. The ink-jet technology was compatible with herbicides, fungicides, insecticides, and beneficial microbes that remained functional after passing through the system. In addition, ink-jet technology demonstrated higher area performance compared to standard nozzles under laboratory conditions. Finally, the application of ink-jet technology to microgreens, which are characterized by small plants, was successful and opened the possibility of full automation of the pesticide application system. The ink-jet system proved to be compatible with the main classes of agrochemicals and showed significant potential for application in protected cropping systems.

Rheology as a Tool for Fine-Tuning the Properties of Printable Bioinspired Gels.

Over the last decade, efforts have been oriented toward the development of suitable gels for 3D printing, with controlled morphology and shear-thinning behavior in well-defined conditions. As a multidisciplinary approach to the fabrication of complex biomaterials, 3D bioprinting combines cells and biocompatible materials, which are subsequently printed in specific shapes to generate 3D structures for regenerative medicine or tissue engineering. A major interest is devoted to the printing of biomimetic materials with structural fidelity after their fabrication. Among some requirements imposed for bioinks, such as biocompatibility, nontoxicity, and the possibility to be sterilized, the nondamaging processability represents a critical issue for the stability and functioning of the 3D constructs. The major challenges in the field of printable gels are to mimic at different length scales the structures existing in nature and to reproduce the functions of the biological systems. Thus, a careful investigation of the rheological characteristics allows a fine-tuning of the material properties that are manufactured for targeted applications. The fluid-like or solid-like behavior of materials in conditions similar to those encountered in additive manufacturing can be monitored through the viscoelastic parameters determined in different shear conditions. The network strength, shear-thinning, yield point, and thixotropy govern bioprintability. An assessment of these rheological features provides significant insights for the design and characterization of printable gels. This review focuses on the rheological properties of printable bioinspired gels as a survey of cutting-edge research toward developing printed materials for additive manufacturing.

On the mechanism of painful burn sensation in tattoos on magnetic resonance imaging (MRI). Magnetic substances in tattoo inks used for permanent makeup (PMU) identified: Magnetite, goethite, and hematite.

BACKGROUND: Persons with cosmetic tattoos occasionally experience severe pain and burning sensation on magnetic resonance imaging (MRI). OBJECTIVE: To explore the culprit magnetic substances in commonly used permanent makeup inks. MATERIAL AND METHODS: 20 inks used for cosmetic tattooing of eyebrows, eyeliners, and lips were selected. Ink bottles were tested for magnetic behavior with a neodymium magnet. Eight iron oxide inks qualified for the final study. Metals were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The magnetic fraction of inks was isolated and analyzed by X-ray fluorescence (XRF). Magnetic iron compounds were characterized by Mössbauer spectroscopy and powder X-ray diffraction (XRD). RESULTS: ICP-MS showed iron in all magnetic samples, and some nickel and chromium. Mössbauer spectroscopy and XRD detected ferromagnetic minerals, particularly magnetite, followed by goethite and hematite. CONCLUSION: This original study of cosmetic ink stock products made with iron oxide pigments reports magnetic impurities in inks for cosmetic tattooing, e.g., magnetite, goethite, and hematite. These may be the main cause of MRI burn sensation in cosmetic tattoos. The mechanism behind sensations is hypothesized to be induction of electrical stimuli of axons from periaxonal pigment/impurity activated by magnetic force. Magnetite is considered the lead culprit.

Efficacy of Manufacturer Recommendations for the Control of Salmonella Typhimurium and Listeria monocytogenes in Food Ink Capsules Utilized in 3D Food Printing Systems.

The adoption of 3D food printing systems has allowed for the personalization of food properties such as color, shape, and texture. This study aimed to determine if manufacturer cleaning recommendations for stainless steel food ink capsules utilized in 3D food printers adequately control foodborne pathogens of concern, as the recommendations have not been tested. A cocktail of ∼9 log10 CFU/mL each of Salmonella Typhimurium and Listeria monocytogenes was inoculated onto the interior surface of the capsules. Capsules were either unsoiled or soiled with one of the following: butter, protein powder solution, powdered sugar solution, or a mixture containing all three food components. The prepared capsules underwent one of three hygienic protocols: manual washing (MW), a dishwasher speed cycle (DSC), or a dishwasher heavy cycle (DHC). The interaction effect between DSC and the soil mixture was significant (P = 0.01), with the combination achieving an estimated mean log reduction of 5.28 (95% CI: 4.61, 6.05) for L. monocytogenes and 6.69 (95% CI: 6.03, 7.41) for S. Typhimurium. The DSC was the least effective method of cleaning when compared with MW and the DHC. No significant differences were found by placing capsules on the right or left side of the dishwasher (P > 0.1). The interaction effect between wash type and capsule position was significant (P = 0.0007), with the soil mixture and DSC combination achieving an estimated mean log reduction of 3.48 (95% CI: 2.72, 4.45) for the front-most position versus 7.92 (95% CI: 6.72, 9.31) for the back-most position. Soil matrix, cleaning protocol, and capsule position all significantly impact capsule cleanability and therefore food safety risk. The DHC is recommended, and the corners should be avoided during dishwasher loading. The current study provides practical information for consumers, restaurants, industry, and regulatory industries regarding the best practices for cleaning 3D food printers.

Hypersensitivity to permanent tattoos: Literature summary and comprehensive review of patch tested tattoo patients 1997-2022.

We outline constituents of tattoo and permanent make-up ink with regard to inflammatory tattoo reactions and population-based confounders. The comprehensive review of patch-tested tattoo patients between 1997 and 2022 shows that tattoo allergy cannot be reliably diagnosed via patch testing with today's knowledge. Weak penetration and slow haptenization of pigments, unavailability of pigments as test allergens and a lack of knowledge concerning relevant epitopes hamper the diagnosis of tattoo allergy. Patch testing p-phenylenediamine and disperse (textile) dyes is not able to close this gap. Sensitization to metals was associated with all types of tattoo complications, although often not clinically relevant for the tattoo reaction. Binders and industrial biocides are frequently missing on ink declarations and should be patch tested. The pigment carbon black (C.I. 77266) is no skin sensitizer. Patch tests with culprit inks were usually positive with cheap ink products for non-professional use or with professionally used inks in patients with eczematous reactions characterized by papules and infiltration. Tape stripping before patch testing and patch test readings on Day 8 or 10 may improve the diagnostic quality. The meaningfulness of the categorical EU-wide ban of Pigment Green 7 and Pigment Blue 15:3 is not substantiated by the presented data.

Preparation and evaluation of sustained release formulation of PLGA using a new injection system based on ink-jet injection technology.

We developed a method for the preparation of PLGA particles exhibiting long-term sustained-release of entrapped drugs. The fine droplet drying (FDD) technology using a new injection system based on ink-jet injection technology was adapted as the preparation method. PLGA microspheres containing TRITC-dextran, acetaminophen, and albumin as model drugs were prepared by the FDD technology. The resultant microspheres were uniform in size, with average particle sizes ranging from 16.3 to 33.0 µm and SPAN factors ranging from 0.49 to 0.77. The encapsulation efficiency of drugs showed high values ranging from 75 to 99 wt% of the total amount of water-soluble drug contained in the particles. In an investigation of the optimal operation conditions of the FDD technology, the dew point temperature of the dryer air stream was found to be an important factor for controlling the initial burst of the prepared particles. The TRITC-dextran-containing PLGA microspheres were confirmed to exhibit long-term sustained release for about 90 days, and the mechanism was found to be PLGA degradation rate-limiting. Based on these results, we concluded that long-term sustained-released PLGA particles can be prepared by using FDD technology under a suitable drying condition for controlling the initial burst.