Core-shell Beads Research Articles

Effect of inulin on structural, physicochemical, and in vitro gastrointestinal tract release properties of core-shell hydrogel beads as a delivery system for vitamin B12

In this study, core-shell hydrogel beads were developed as a controlled-release delivery system for vitamin B12. Vitamin B12-loaded microgels (MG) were prepared using gellan gum (GG). Core-shell hydrogel beads were produced by incorporating MG into pea protein isolate (PPI) and sodium alginate (AL) matrix filled/coated with different concentrations (0 %, 1 %, 3 %, 5 %, and 10 %) of inulin (IN). Based on XRD analysis, MG was successfully incorporated into core-shell hydrogel beads. In FE-SEM and FT-IR analyses, the smoother surface and denser structure of the beads were observed as IN concentration increased due to hydrogen bonds between IN and the beads. The encapsulation efficiency increased from 68.64 % to 82.36 % as IN concentration increased from 0 % to 10 %, respectively. After exposure to simulated oral and gastric conditions, core-shell hydrogel beads exhibited a lower cumulative release than MG, and a more sustained release was observed as IN concentration increased in simulated intestinal conditions.

Development of Tetramycin-Loaded Core–Shell Beads with Hot-/Wet-Responsive Release Properties for Control of Bacterial Wilt Disease

Plant bacterial wilt is caused by Ralstonia solanacearum, a soilborne pathogen that infects plant conduits, leading to wilt disease. It is extremely difficult to cure plants infected with Ralstonia solanacearum; however, bactericide-loaded beads with hot-/wet-responsive properties may be able to release a biocide in line with the increase in the hot-/wet-associated activity of Ralstonia solanacearum, effectively killing the pathogenic cells and providing high levels of plant protection. A biopesticide, Tetramycin, was embedded in corn kernel powder (CKP)-based cores. An oil-phase mixture was sprayed onto the core surface to form a hot-/wet-responsive intermediate shell (IMS). Subsequently, a layer of ethyl cellulose (EC) and hydroxypropyl methyl cellulose (HPMC) was coated onto the IMS to create a single wet-responsive outer shell (OTS). The ratios of the components in the cores, including the corn kernel powder (CKP), xanthan gum (XG), and Tetramycin, were optimized, as well as those of the IMS, including pentaerythrityl tetrastearate (PETS), pentaerythrityl tetraoleate (PETO), polyethylene glycol stearate (PEG400MS), and polyethylene glycol monooleate (PEG400MO), and those of the outer shell (OTS), including ethyl cellulose (EC) and hydroxypropyl methyl cellulose (HPMC). A texture performance analysis, differential scanning calorimetry (DSC) analysis, thermogravimetric analysis (TGA), temperature and humidity response performance tests, scanning electron microscope (SEM) observations, and a field effectiveness test were conducted to characterize the Tetramycin-loaded beads. The results indicated that the optimal formula for the bead cores comprised a mass ratio of CKP/Tetramycin solution/XG = 13.5:23:2. The preferred mass ratio for IMS was PETS/PETO/PEG400MO = 10:30:10, and the formula for the applicable OTS consisted of a mass ratio of EC/HPMC = 5:1. In soil with a temperature of 30–35 °C and humidity of 30%, the release period of the Tetramycin-loaded beads, with a cumulative release rate of over 95%, could last up to 35 days. Furthermore, the Tetramycin-loaded beads exhibited a gradual and multi-cyclic release process under alternating hot/wet and dry/cold environments. The relative preventive efficacy of 54.74% on tobacco was revealed at a field-testing scale. A significant reduction in the abundance of Ralstonia solanacearum was also observed under treatment with the Tetramycin-loaded beads. The early fungal community structure exhibited higher consistency compared to the control. However, in the later stage, the diversity differences between the soil layers were restored. In conclusion, Tetramycin-loaded beads that could effectively respond to temperature and humidity fluctuations were developed, resulting in enhanced disease prevention efficacy and offering broad prospects for the prevention and control of Ralstonia solanacearum in agricultural settings.

A Stable and Sensitive Engineering Bacterial Sensor via Physical Biocontainment and Two-Stage Signal Amplification.

Although engineering bacterial sensors have outstanding advantages in reflecting the actual bioavailability and continuous monitoring of pollutants, the potential escape risk of engineering microorganisms and lower detection sensitivity have always been one of the biggest challenges limiting their wider application. In this study, a core-shell hydrogel bead with functionalized silica as the core and alginate-polyacrylamide as the shell have been developed not only to realize zero escape of engineered bacteria but also to maintain cell activity in harsh environments, such as extremely acidic/alkaline pH, high salt concentration, and strong pressure. Particularly, after combining the selective preconcentration toward pollutants by functionalized core and the positive feedback signal amplification of engineering bacteria, biosensors have realized two-stage signal amplification, significantly improving the detection sensitivity and reducing the detection limit. In addition, this strategy was actually applied to the detection of As(III) and As(V) coexisting in environmental samples, and the detection sensitivity was increased by 3.23 and 4.39 times compared to sensors without signal amplification strategy, respectively, and the detection limits were as low as 0.39 and 0.86 ppb, respectively.

An Exploration of various Fructooligosaccharides production methods using novel engineered enzymes with innovative core-shell chitosan beads

This study investigates Fructooligosaccharides (FOSs) production as prebiotics to promote gut health and overall well-being. Various production methods for FOSs were explored, leveraging novel engineered inulosucrase (IN) and levansucrase (LV) enzymes. The methodologies included batch stirred reactors with free enzymes and fixed-bed reactors utilizing enzymes immobilized on hydrogel chitosan beads (HGBs) and core-shell chitosan beads (CSBs). The study found that free enzymes exhibited the highest sucrose consumption rates, with IN achieving 142.8 g/L∙h and LV achieving 82.9 g/L∙h. However, CSB-immobilized enzymes demonstrated substantial enzyme savings (55% and 41% reduction in IN and LV consumption, respectively) through reuse across multiple cycles, while delivering superior FOSs yields. CSB-immobilized enzymes outperformed HGB-immobilized enzymes in terms of immobilization efficiency, activity recovery, sucrose conversion, FOSs yields, and repeatability. A novel reactor setup involving interconnected fixed-bed reactors with different enzymes in series produced promising results, generating novel FOSs species alongside expected I-FOSs and L-FOSs. Consumable cost analysis indicated that while free enzyme usage is initially cost-effective (5.09–7.06 USD/kg FOSs), significant increases in LV prices could make CSB immobilization a cost-competitive alternative. This study highlights the potential of innovative enzyme immobilization strategies and reactor designs for efficient FOSs production, considering both performance and economic feasibility.

Chitosan-functionalized poly(3-hydroxybutyrate) bead as a novel biosupport for palladium in the Suzuki cross-coupling reaction

The utilization of environmentally friendly biopolymer poly(3-hydroxybutyrate) (PHB) as a support for metal catalysts is an unexplored area. Herein, exploring a stable and recyclable heterogeneous palladium (Pd) catalyst based on PHB for the Suzuki cross-coupling reaction is an attractive topic. In this study, a novel hydrophobic and hydrophilic core-shell bead supported Pd catalyst was developed by using PHB particle as a hydrophobic rigid framework and hydrophilic chitosan (CS) as the surface of the supporting matrix to fix Pd nanoparticles (NPs). The results of structural characterization showed that the Pd NPs with a small average size of 2.3±0.82 nm were uniformly distributed on the surface of the PHB-CS bead with a Pd content of 0.12 wt%. This demonstrated that the PHB-CS bead created a stable coordinated environment for Pd fixation, preventing Pd leaching. Furthermore, the Pd@PHB-CS catalyst exhibited high catalytic efficiency with 99% conversion in the Suzuki reaction under mild conditions, using a solvent mixture of EtOH and H2O (1:1) for 0.5 h. It is worth noting that the catalyst exhibits excellent stability, and reusability. It can be reused five times without a significant reduction in activity while maintaining its structural integrity. The successful construction of Pd@PHB-CS will further expand the application of PHB in the field of metal catalysts and may help establish a green and environmentally friendly multifunctional platform for the development of highly recyclable heterogeneous catalysts containing metal nanoparticles.

Investigation of swelling behaviour monolayer and double Layer polysaccharide based composite hydrogels

ABSTRACT In this study, monolayer and double layer (core-shell) composite hydrogel beads with and without hydroxyapatite which have potential applications in drug delivery systems were synthesized, and their swelling behaviours were investigated in different pH mediums. The composite hydrogel beads was prepared by crosslinking sodium alginate and kappa-carrageenan (by using Ca+2 and K+1). Core-shell hydrogel beads were formed by coating monolayer composite hydrogel beads with the mixture of sodium alginate and kappa-carrageenan. The structure of hydrogel beads was characterized by Fourier Transform Infrared Spectrophotometer, Scanning Electron Microscopy and Differential Scanning Calorimetry. The effects of the composite hydrogel beads combination and the concentration of crosslinker on swelling behaviours were investigated. Swelling kinetics data were tested using pseudo-second-order model, and the pseudo-second-order model is estimated as a convenient model to represent the swelling kinetic. The results indicated that swelling behaviours of hydrogel beads changed with composite hydrogel beads combination and concentration of crosslinker.

One-step biofabrication of liquid core-GelMa shell microbeads for in situ hollow cell ball self-assembly.

There are many instances of hollow-structure morphogenesis in the development of tissues. Thus, the fabrication of hollow structures in a simple, high-throughput and homogeneous manner with proper natural biomaterial combination is valuable for developmental studies and tissue engineering, while it is a significant challenge in biofabrication field. We present a novel method for the fabrication of a hollow cell module using a coaxial co-flow capillary microfluidic device. Sacrificial gelatin laden with cells in the inner layer and GelMa in the outer layer are used via a coaxial co-flow capillary microfluidic device to produce homogenous micro-beads. The overall and core sizes of core-shell microbeads were well controlled. When using human vein vascular endothelial cells to demonstrate how cells line the inner surface of core-shell beads, as the core liquifies, a hollow cell ball with asymmetric features is fabricated. After release from the GelMa shell, individual cell balls are obtained and deformed cell balls can self-recover. This platform paves way for complex hollow tissue modeling in vitro, and further modulation of matrix stiffness, curvature and biochemical composition to mimic in vivo microenvironments.

Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

Improving the thermal stability of phytase using core-shell hydrogel beads

A core–shell hydrogel bead system was designed to maintain the catalytic activity of phytase and protect its enzymatic functionality from heat treatment. The designed structure consists of a chitosan-phytase complex core and an alginate-carrageenan hydrogel shell. The core–shell hydrogel was optimized to improve phytase encapsulation efficiency and increase the thermal stability of the encapsulated phytase. After heat treatment, encapsulated phytase retained ∼ 70 % of its catalytic activity and the same secondary structure of free phytase. Fourier transform infrared spectroscopy indicated strong intermolecular interactions between chitosan and phytase in the core, but little interaction between the core and the alginate and κ-carrageenan shell, this supports the structural and functional stability of the phytase. Differential scanning calorimetry confirmed that the designed core–shell structure had a higher melting point. Encapsulating phytase in a core–shell hydrogel bead can enhance the thermal stability of phytase, which broadens the potential applications for phytase delivery.

Fabrication of core–shell beads, hollow capsules, and AuNP-embedded catalytic beads from an ultrasmall peptide hydrogel

Hydrogel beads have emerged as a new class of soft materials that infuse the noble properties of macro-dimensional hydrogels in tiny, easily operable, and robust droplets. Usually, polymeric hydrogels are used in the production of hydrogel beads due to their high structural rigidity and durability, and low molecular weight hydrogel beads are relatively uncommon. Herein, we employed an ultra-short peptide (Pyrene-Lys-Cys, PyKC) based low molecular weight injectable hydrogel, that remains insoluble in bulk solvents, to create stable hydrogel beads using a simple extrusion technique. To enhance durability and applicability, the beads are coated with a polymeric shell, resulting in a core–shell configuration. The shell of the core–shell beads can be modified through a variety of organic conjugation reactions. Also, the core (hydrogel) can be sacrificed using DMSO, resulting in the formation of hollow organic capsules. Furthermore, the core–shell beads enabled the in-situ synthesis and stabilization of gold nanoparticles on the bead surface. The gold-loaded beads demonstrated remarkable catalytic efficiency in the reduction of p-nitrophenol and hazardous azo dyes. In a nutshell, the extremely modular and customizable nature of the PyKC-based core–shell hydrogel bead may allow it to function as a unified platform for multifaceted applications.

Fabricating Shaped and Patterned Supramolecular Multigelator Objects via Diffusion-Adhesion Gel Assembly.

We report the use of acid-diffusion to assemble core-shell supramolecular gel beads with different low-molecular-weight gelators (LMWGs) in the core and shell. These gel beads grow a shell of dibenzylidenesorbitol-based DBS-COOH onto a core comprising DBS-CONHNH2 and agarose that has been loaded with acetic acid. Diffusion of the acid from the core triggers shell assembly. The presence of DBS-CONHNH2 enables the gel core to be loaded with metal nanoparticles (NPs) as acyl hydrazide reduces metal salts in situ. The pH-responsiveness of DBS-COOH allows responsive assembly of the shell with both temporal and spatial control. By fixing multiple gel beads in a Petri dish, the cores become linked to one another by the assembled DBS-COOH gel shell─a process we describe as diffusion-adhesion assembly. By controlling the geometry of the beads with respect to one another, it is possible to pattern the structures, and using a layer-by-layer approach, 3D objects can be fabricated. If some of the beads are loaded with basic DBS-carboxylate instead of CH3COOH, they act as a "sink" for diffusing protons, preventing DBS-COOH shell assembly in the close proximity. Those beads do not adhere to the remainder of the growing gel object and can be simply removed once diffusion-assembly is complete, acting as templates, and enabling the fabrication of 3D "imprinted" multigel architectures. Preloading the gel beads with AuNPs or AgNPs suspends these functional units within the cores at precisely defined locations within a wider gel object. In summary, this approach enables the dynamic fabrication of shaped and patterned gels with embedded metal NPs─such objects have potential next-generation applications in areas including soft nanoelectronics and regenerative medicine.

Mangiferin loaded carrageenan/chitosan core-shell hydrogel beads: Preparation, characterization and proposed application

In this work, an investigation on the use of mangiferin, a bioactive compound, in a controlled release hydrogel system was carried out. Mangiferin isolated from mango leave waste was tested for its antibacterial activities by disc diffusion, agar well and agar dilution methods. The results confirmed effective antibacterial effects against Vibrio parahaemolyticus and Vibrio cholerae, the common species found in fresh seafood that can cause acute diarrheal illness. However, application of this polyphenolic natural compound is limited by its poor water solubility resulting in low bioavailability. To overcome is limitation, biopolymeric core-shell hydrogel beads incorporated with mangiferin were fabricated by a one-step gelling method. The core particles loaded with mangiferin were prepared from κ-carrageenan solution which were subsequently ionic-crosslinked and encapsulated with the chitosan shells. The formation of core-shell morphology was verified by light microscope observation and confirmed that the κ-carrageenan core was completely covered with the uniform shell of chitosan. The composition of microsphere beads was also examined with Fourier transform infrared spectroscopy and scanning electron microscopy equipped with energy dispersive X-ray analysis. The core-shell hydrogel was able to encapsulate mangiferin with the optimum loading efficiency of 85%. The release kinetics was evaluated at different temperatures and Korsmeyer-Peppas was the most appropriate model to represent the release profiles of mangiferin from hydrogel beads. Biocompatibility test performed on all of the hydrogel samples exhibited a good viability for the L929 and Vero cells with low cytotoxicity. Investigations on the microsphere hydrogels revealed that they could regulate the release of bioactive mangiferin and possessed promising potential to be utilized for quality protection of fresh seafood.

ZSM-5/Silicalite-1 core-shell beads as CO2 adsorbents with increased hydrophobicity

Zeolites are commonly used for selective CO2 adsorption from biogas and flue gas. One of the biggest challenges for zeolites in this application is the presence of water vapour in the raw gas streams. While zeolites with low Si/Al ratio typically display high CO2 adsorption, they are hydrophilic and H2O competes for adsorption on the active sites. On the other hand, zeolites with high Si/Al ratio are hydrophobic, but display lower CO2 adsorption capacities. In order to overcome this limitation and to combine the high CO2 adsorption capacity of low Si/Al zeolites and the hydrophobicity of high Si/Al zeolites into a single material, we designed and synthesized novel core-shell zeolitic beads comprising a ZSM-5 core and a Silicalite-1 shell. Two different strategies were employed to synthesize these macroscopic core-shell beads. In both approaches, the initial step was the synthesis of binderless ZSM-5 beads with hierarchical porosity using resin beads as hard template. In the first strategy, a shell of Silicalite-1 was synthesized on the external surface of the calcined ZSM-5 beads, yielding Sil-ZSM-A core-shell beads (0.84 ± 0.12 mm). In the second strategy, the Silicalite-1 shell was synthesized without first removing the polymeric template from the ZSM-5 beads, resulting in core-shell composite beads that after calcination yielded Sil-ZSM-B core-shell beads (0.73 ± 0.14 mm). Characterization by SEM, XRD, XRF, ICP-AES and N2 physisorption indicated that both Sil-ZSM-A and Sil-ZSM-B beads displayed the desired zeolitic core-shell structure with hierarchical porosity. Both core-shell beads showed the anticipated increase in hydrophobicity. The most promising results were obtained with Sil-ZSM-A beads, which displayed a 40% decrease in H2O adsorption capacity at 20% relative humidity (RH) and a 28% decrease at max RH compared to the parent ZSM-5 beads. At the same time, their CO2 adsorption capacity (1.94 mmol/g at 1 bar) decreased only slightly compared to the parent ZSM-5 beads (2.13 mmol/g at 1 bar). These results indicate that these core-shell beads present the desired combination of the high CO2 adsorption capacity of the ZSM-5 core with the hydrophobicity of the Silicalite-1 shell. This is a promising feature for application in the adsorption of CO2 from water-containing streams.

High-Throughput Generation, Manipulation, and Degradation of Magnetic Nanoparticleladen Alginate Core-shell Beads for Single Bacteria Culturing Analysis.

Microbes could be found almost everywhere around us and have significant impacts on our human society. The treatment of microorganisms has long been seen as a complex problem. Till now, most of the genetic and phenotypic information regarding rare species is buried in the bulk microbial colony due to a lack of efficient tools to screen live bacteria. Droplet microfluidics offers a powerful approach to address this problem. However, the interactions among bacteria and their living environment are entirely restricted by the water/oil interfaces in conventional water/oil single emulsion-based microfluidic systems. Here, we demonstrate an oil-mediated all-aqueous microfluidic workflow that can overcome this drawback. In contrast to the previous works, our all-aqueous culturing environment allows cell-cell and cell-environment interactions, thus facilitating the growth of bacteria. Fe3O4 magnetic nanoparticles added into the alginate beads enables on-chip manipulation of the microcapsules. The core-shell structure separately encapsulates bacteria and magnetic particles in the core and shell to avoid contamination. We demonstrate the feasibility of this approach by single bacterium culturing in droplet-templated alginate beads. Finally, a new approach is proposed to degrade the alginate beads for post-treatment. This novel microfluidic workflow can create new opportunities for microbial applications, such as bacteria culturing and screening.

Mapping the low abundant plasma glycoproteome using Ranachrome-5 immobilized magnetic terpolymer as improved HILIC sorbent

HILIC (hydrophilic interaction liquid chromatography) materials enrich glycopeptides. The non-specific interactions because of support material and inadequate hydrophilicity render loss of less abundant glycopeptides in SPE-based enrichments. In this work, magnetic terpolymer (Fe3O4@MAA/DVB/1,2-Epoxy-5-hexene) is functionalized with Ranachrome-5 to generate enhanced hydrophilicity. Amine, carboxylic, and amide groups of ranachrome-5 provide zwitterionic chemistry. Material’s magnetic core contributes to ease of operation while higher surface area 97.0711 m2 g−1 immobilizes better quantities of Ranachrome-5. Homogeneous morphology, nano-size, and super hydrophilicity enhance enrichment. Ranachrome-5 functionalized polymeric core-shell beads enrich 25, 18 and 16 N-linked glycopeptides via SPE strategy from tryptic digests of model glycoproteins i.e., immunoglobulin G (IgG), horseradish peroxidase (HRP) and chicken avidin, respectively. Zwitterionic chemistry of ranachrome-5 helps in achieving higher selectivity (1:250, HRP / Bovine Serum Albumin), and lower detection limit (100 attomole, HRP digest) with complete glycosylation profile of each standard digest. High binding capacity (137.1 mg/g) and reuse of affinity material up to seven cycles reduce the cost and amount of affinity material for complex sample analysis. A recovery of 91.76% and relative standard deviation (RSD) values less than 1 define the application of HILIC beads for complex samples like plasma. 508 N-linked intact low abundant glycopeptides corresponding to 50 glycoproteins are identified from depleted human plasma samples via nano-Liquid Chromatography-Tandem Mass Spectrometry (nLC-MS/MS). Using Single Nucleotide Variances (BioMuta) for low abundant plasma glycoproteins, the potential association of proteins to four cancers, i.e., breast, lung, uterine, and melanoma is evaluated. Via the bottom-up approach, HILIC beads can analyze clinically important low-abundant glycoproteins.

Toxicity of per- and polyfluoroalkyl substances to microorganisms in confined hydrogel structures

Per- and polyfluoroalkyl substances (PFAS) as a group of environmentally persistent synthetic chemicals has been widely used in industrial and consumer products. Bioaccumulation studies have documented the adverse effects of PFAS in various living organisms. Despite the large number of studies, experimental approaches to evaluate the toxicity of PFAS on bacteria in a biofilm-like niche as structured microbial communities are sparse. This study suggests a facile approach to query the toxicity of PFOS and PFOA on bacteria (Escherichia coli K12 MG1655 strain) in a biofilm-like niche provided by hydrogel-based core-shell beads. Our study shows that E. coli MG1655 upon complete confinement in hydrogel beads exhibit altered physiological characteristics of viability, biomass, and protein expression, compared to their susceptible counterpart cultivated under planktonic conditions. We find that soft-hydrogel engineering platforms may provide a protective role for microorganisms from environmental contaminants, depending on the size or thickness of the protective/barrier layer. We expect our study to provide insights on the toxicity of environmental contaminants on organisms under encapsulated conditions that could potentially be useful for toxicity screening and in evaluating ecological risk of soil, plant, and mammalian microbiome.

Multi-functional core-shell pomegranate peel amended alginate beads for phenol decontamination and bio-hydrogen production: Synthesis, characterization, and kinetics investigation

Phenolic compounds discharged from different industries comprise a great threatening to environmental system and human health. They are toxic even at a low concentration (<1.0 μg/L). Adsorption is attractive scenario for successful removal of phenolic compounds from wastewater. Herein, a facile strategy was employed to fabricate amended alginate beads based on pomegranate peel. The constructed beads were intensively scrutinized, and introduced for the remediation of phenol from wastewater under various operational parameters of pHi (e.g., 2.1–10.7), adsorbent dose (e.g., 0.5 – 5.0 g L−1), initial phenol concentrations (e.g., 10.0 – 500.0 mg L−1), and residence time (e.g., 5.0 – 270.0 min). Consequently, the efficacy of bio-hydrogen production via dark fermentative process of co-substrate metabolism of phenol and glucose in presence of beads was systematically inspected. Our findings revealed that the maximum adsorption capacity of beads was 119.048 mg g−1 at pH 7.2. Comfortingly, the fitting isotherms experiments expounded that the adsorption of phenol by beads conformed to the Langmuir model. The kinetics modelling findings matched with pseudo-second-order model. Otherwise, the as-prepared beads have remarkably improved anaerobic co-substrate fermentation process of glucose (synergism) and phenol removal efficiency (91.1–97.0%), with bio-hydrogen yield of 0.35 up to 2.65 mol-H2 mol−1 glucose. Overall, the present study illustrates an ample perspective of natural resources feasibility as a futuristic rational platform for wastewater decontamination and bio-hydrogen production.

Precise, wide field, and low-cost imaging and analysis of core-shell beads for digital polymerase chain reaction.

Digital droplet reactors have become a valuable tool for the analysis of single cells, organisms, or molecules by discretising reagents into picolitre or nanolitre volumes. However, DNA-based assays typically require processing of samples on the scale of tens of microlitres, with the detection of as few as one or as many as a hundred thousand fragments. Through the present work, we introduce a flow-focusing microfluidic device that produces 120 picolitre core-shell beads, which are assembled into a monolayer in a Petri dish for visualization and analysis. The bead assembly is subjected to polymerase chain reaction (PCR) amplification and fluorescence detection to digitally quantify the DNA concentration of the sample. We use a low-cost 21-megapixel digital camera and macro lens to capture wide-field fluorescence images with a 10-30 mm2 field-of-view at magnifications ranging from 5× to 2.5×. A customised Python script analysed the acquired images. Our study demonstrates the ability to perform digital PCR analysis of the entire bead assembly through end-point imaging and compare the results with those obtained through RT-qPCR.

Confining SnS2@N, S codoped carbon in core-shell beads of necklace-like fibers towards ultrastable anode for flexible potassium-ion battery

Tin sulfide (SnS2) with high theoretical capacity and layered structure is a promising anode candidate for potassium-ion batteries (PIBs). However, the sluggish kinetics, huge volume expansion and polysulfide intermediates dissolution restrict its development. To address these issues, a necklace-like hybrid fiber with core–shell beads is designed to achieve the high-performance anode for PIBs. The cores of the beads are assembly by SnS2 nanocrystals dotted in N, S codoped carbon (NSC) matrix. Then they are encapsulated by NSC based shell and form the core–shell structured beads internal the hybrid fiber (CSN fiber). The carbon matrix of SnS2@NSC CSN fiber gives fast ion/electron pathways and facilitates to decrease particle aggregation. Meanwhile, N, S codpants favor to trap the polysulfides intermediates and alleviate the sulfur loss during cycling. Moreover, the voids internal the beads further provide the high accommodation to volume change. Taken all above advantages, the SnS2@NSC CSN fiber achieves the excellent high rate capability and ultrastable cycling property, which obtains a low capacity decay rate of 0.013% after 2000 cycles at 2 A g−1. Moreover, its good mechanical characteristics ensure the fabrication of the flexible PIB full cell, which achieves the high pliability, superior power/energy density and high reliability in diverse working conditions. Therefore, this work not only gives a new clue to design the high-performance electrode for potassium storage, but also propels the applications of PIBs for diverse electronics.

Thermo-mechanical response of liquid-core beads as affected by alginate molecular structure

Core-shell hydrogel beads have recently drawn considerable attention to meet ever-changing consumer demand for exciting texture combined with functional properties. Still, the thermal processing of these types of beads remains insurmountable. In this paper, spherical liquid core gel beads were prepared from alginate with distinguishable Mw and M/G ratios and treated at temperatures varying from 60 to 121 °C. The core and the shell both had a precise response and influence towards heat. Improved mechanical properties were observed from beads up to 100 °C, figuring on hydrogels' network structure. High G-content and high molecular weight (Mw) contributed broadly up to a 50% increase in bursting force at high temperatures. Above the boiling point, beads started losing their original geometry since core materials diffused at an accelerated rate with a vapor pressure buildup. An irregular pattern of reduction in shell thickness, depending on crosslinking nature, was observed among alginate beads during heat treatment. A maximum 63.4% thickness reduction was recorded from low Mw alginate. Poorly constructed gel networks produced thermally vulnerable structures, predominantly by shorter chain length or higher M residue. Higher calcium concentration (up to a saturated crosslinking point) enhanced stability within the same alginate group. Heat treatment resulted in a compact shell microstructure with reduced pore size and a smoother surface. The water state and crosslinking of the chains were the decisive factors for the beads' thermo-mechanical response. Thus, a relationship was established between liquid-core beads' structural integrity, stability, and alginate's molecular composition concerning thermal treatment. • A relationship of thermo-mechanical response with alginate gel-structure established. • Beads' mechanical properties were enhanced by heating up to an optimum temperature. • The spherical geometry of liquid core alginate beads (LCB) persist up to 100 °C. • Alginate with High G content was more suitable for heat treatment for LCB. • High temperature reduces roughness and porosity of beads' shell.