Capsule Formation Research Articles

One‐Pot Synthesis of [(l‐GluA)‐b‐(PCL)]‐Based Diblock Copolymer and Solvent‐Assisted Multifaceted Capsules as Potential Cargo Payload for Nanomedicines

Abstract This study shows that the synthesis of di‐BCP between amino acid l‐glutamic acid (l‐GluA) and hydrophobic polycaprolactone (PCL) leads to multifunctional and multifaceted capsule formation with different dispersion solvents. Successful synthesis of [(l‐GluA)‐b‐(PCL)] was confirmed by using FTIR and 1H NMR characterizations. For morphological studies, synthesized di‐BCP of [(l‐GluA)‐b‐(PCL)] was dispersed in four different solvents such as acetone, DMSO, IPA, and ethanol and was used for sample preparation for SEM imaging. Interestingly, smooth‐surfaced NPs (defined as type I NPs), rough‐surfaced NPs (type II NPs), porous NPs (type III NPs), and football‐type deep excavation having NPs (defined as type IV NPs). Furthermore, these NPs were characterized through BET, AFM, and DLS for particle size and ζ potential of NPs. LC for types III and IV NPs was calculated to be 1.96% ± 0.01% and 1.92% ± 0.01%, respectively. EE of types III and IV NPs was calculated to be 91% ± 1.5% and 94% ± 1.2%. We used K562 (leukemia blood cancer) and HEK293 (embryonic kidney) cells for in vitro studies. DOX@[(l‐GluA)‐b‐(PCL)] nanoformulation related to types III and IV NPs shows significant early apoptosis that is, 29.17%, which is a remarkable programmed cell death for these porous nanoparticles.

Decomposition and Changes in InVivo Post-HA Filler Injection: A Review.

Hyaluronic acid (HA) fillers are widely used in aesthetic medicine, but their invivo behavior and long-term effects are not fully understood. To review the decomposition and changes occurring in the body following HA filler injections, focusing on crosslinking agents, degradation processes, and tissue responses. This review analyzed oxidative and enzymatic degradation processes of HA fillers, evaluated the impact of 1,4-Butanediol Diglycidyl Ether (BDDE) crosslinking, and examined histological changes post-injection. Uncrosslinked HA degrades rapidly due to endogenous hyaluronidase, while crosslinked HA undergoes slower degradation via free radicals and hyaluronidase. Complete cross-linking (C-MoD) showed better durability compared to partially cross-linked BDDE (P-MoD). The concept of modification efficiency (MoE) was proposed to optimize filler safety and viscoelastic properties. Histological analysis revealed collagen capsule formation and autologous tissue replacement, affecting long-term outcomes. The degree of chemical modification (MoD) influences filler durability and safety, with concerns raised about potential delayed immune reactions from accumulated pendent BDDE. Clinicians should consider injection site, tissue conditions, and filler properties for safe and effective HA filler use. Emphasizing thorough BDDE removal and optimal crosslinking can enhance treatment safety and efficacy. The balance between achieving desired viscoelastic properties and minimizing potential risks is crucial. Future studies should include diverse ethnic groups to validate findings and further explore long-term tissue responses to HA fillers.

Positive Effects of Growth Retardants on Castor (Ricinus communis L.)

The perennial growth habit of castor plants (Ricinus communis L.) limits mechanical harvest because the plant grows very tall, when the environmental conditions are favorable and produces green flush interfering with mechanical harvesting. In order to prevent excessive growth plant growth, retardant are applied to modifying crop architecture. Present investigation was designed to study the effect of growth retardants on growth and yield parameters. The experiment was conducted at the regional agricultural research station, Palem farm of Professor Jayashankar Telangana Agricultural University, Nagarkurnool district, Telangana, taking locally available tall variety PCH-111. The experiment was laid out in Randomized Block Design with three replicates in Kharif, 2019. Treatments comprises of water spray, ethrel@500 ppm, ethrel@1000 ppm, CCC@1.5ml/lit, CCC@2.0 ml/lit and CCC@2.5 ml/lit and sprayings were done at expanding leaf in the 6th node of the primary stem, expanding leaf on the 8th node of the primary stem, appearance of the first inflorescence, one expanding leaf in a secondary stem after the appearance of the first inflorescence, and appearance of the second inflorescence. Results revealed that, plant growth retardants are effective in reducing plant height, whereas no spray recorded significant superior value for plant height (70.73 cm). For leaf number, there is no much deviations though ethrel treatment enhanced senescence in older leaves, newly developed leaves compensated the number but there was reduction in LAI, which were 1.70 and 2.18, respectively, in ethrel spray of 1000 ppm and 500 ppm. The yield reduction is lower in ethrel treatment due to lower capsule formation and lower spike length at higher concentration of ethrel. Hence, it is concluded that, retardant accelerates natural senescence and thus, acting as defoliants overcoming difficulties in mechanical harvesting.

Encapsulation of Liquids via Polymer Precipitation in Emulsions

ABSTRACTMicroencapsulation strategies enable the confinement of sensitive active materials in a protective shell, giving capsules with applications across pharmaceuticals, foodstuffs, agriculture, textiles, cosmetics, and energy storage. Among the different approaches, the soft template encapsulation method is a widely used technique that leverages emulsions as templates and forms spherical microcapsules with a liquid core and polymeric shell. Within the emulsion template umbrella, interfacial polymerization, phase internal phase separation, and polymer precipitation can all be used. The main limitation of interfacial polymerization is that the core will inevitably contain impurities such as residual monomers, which can affect the performance of the encapsulated material. This is especially relevant when performance efficiency strongly depends on its pristine composition. In this perspective, we focus on polymer precipitation soft‐template strategies for capsule formation, and the complementarity of this approach to the more widely used interfacial polymerization. Polymer precipitation strategies enable the encapsulation of sensitive cores (or payloads) and can include those that are viscous, hygroscopic, and reactive.

Designing injectable dermal matrix hydrogel combined with silver nanoparticles for methicillin-resistant Staphylococcus aureus infected wounds healing

Hydrogel-based delivery systems have now emerged as a pivotal platform for addressing chronic tissue defects, leveraging their innate capacity to suppress pathogenic infections and facilitate expedited tissue regeneration. In this work, an injectable hydrogel dressing, termed AgNPs-dermal matrix hydrogel (Ag@ADMH), has been designed to expedite the healing process of wounds afflicted with methicillin-resistant Staphylococcus aureus (MRSA), featuring sustained antibacterial efficacy. The synthesis of the hydrogel dressing entailed a self-assembly process of collagen fibers within an acellular dermal matrix to construct a three-dimensional scaffold, encapsulated with plant polyphenol-functionalized silver nanoparticles (AgNPs). The Ag@ADMH demonstrated exceptional biocompatibility, and enables a sustained release of AgNPs, ensuring prolonged antimicrobial activity. Moreover, the in vitro RT-qPCR analysis revealed that compared with ADMH, Ag@ADMH diminish the expression of iNOS while augmenting CD206 expression, thereby mitigating the inflammatory response and fostering wound healing. Especially, the Ag@ADMH facilitated a reduction in M1 macrophage polarization, as evidenced by a significant decrement in the M1 polarization trend and an enhanced M2/M1 ratio in dermal matrix hydrogels laden with AgNPs, corroborated by confocal microscopy and flow cytometry analyses of macrophage phenotypes. The in vivo assessments indicated that Ag@ADMH minimized fibrous capsule formation. In a full-thickness skin defect model of MRSA infection, the formulation significantly attenuated the inflammatory response by reducing MPO and CD68 expression levels, concurrently promoting collagen synthesis and CD34 expression, pivotal for vasculogenesis, thereby accelerating the resolution of MRSA-infected wounds. These attributes underscore the injectable extracellular matrix hydrogel as a formidable strategy for the remediation and regeneration of infected wounds.Graphical

Detection of virulence factors and antimicrobial susceptibility pattern of clinically significant Klebsiella pneumoniae isolates in a tertiary care hospital

Introduction: Klebsiella pneumoniae is associated with a variety of infections across all age groups, both in community and hospital settings. Many strains of K. pneumoniae produce virulence factors such as a capsule, siderophores, biofilm, and hypermucoviscosity, which facilitate adhesion, invasion, and colonization. Additionally, the rising antibiotic resistance in K. pneumoniae strains poses a significant challenge, limiting treatment options. This study aims to identify the virulence factors and assess the antimicrobial susceptibility of clinically significant K. pneumoniae isolates. Materials and Methods: K. pneumoniae isolates were obtained from urine, sputum, blood, cerebrospinal fluid, pus swabs/aspirates, and tissue samples. Standard biochemical tests were performed for identification. Capsule formation, hypermucoviscosity, siderophore production, and biofilm formation were detected phenotypically. Antibiotic susceptibility testing was carried out using the disk diffusion method, and primary and confirmatory tests were conducted for extended-spectrum beta-lactamases (ESBL) and carbapenemase production. Results: Capsule formation, hypermucoviscosity, siderophore production, and biofilm formation were detected in 100%, 15%, 40%, and 15% of the isolates, respectively. Of the isolates, 40% were multidrug-resistant, 55% produced ESBL, 8% expressed AmpC beta-lactamase, and 10% produced carbapenemase. Conclusion: Capsule formation was the most prevalent virulence factor, followed by siderophore production. The majority of K. pneumoniae isolates demonstrated susceptibility to amikacin, piperacillin-tazobactam, and carbapenems. However, 40% of the isolates were multidrug-resistant, with ESBL production being the most common resistance mechanism.

Spontaneous Formation of Solid Shell Polymeric Multicompartments at All-Aqueous Interfaces.

Multicompartmental capsules have demonstrated value in fields ranging from drug release, mimetics of artificial cells, to energy conversion and storage. However, the fabrication of devices with different compartments usually requires the use of toxic solvents, and/or the adaptation of technically demanding methods, including precision microfluidics and multistep processes. The spontaneous formation of multi-core capsules resulting from polyelectrolyte complexation at the interface of a prototypic all-aqueous two-phase system is described here. The variation of polyelectrolyte concentration and complexation time are described as simple working parameters capable of driving the formation of compartments at different yields, as well as tailoring their morphology. The mild processing technology enables the encapsulation of animal cells, which are capable of invading capsule walls for specific processing conditions.

Hypervirulent Carbapenem-Susceptible Klebsiella pneumoniae ST412/K57 with Strong Biofilm Formation: association with gas gangrene and sepsis.

Hypervirulent Klebsiella pneumoniae (hvKp) poses a serious public health threat. Gas gangrene caused by hvKp was rarely reported, potentially resulting in a poor prognosis. In this study, we described the case of a hospitalized patient with gas gangrene and sepsis by hvKP. The carbapenem-susceptible hypervirulent Klebsiella pneumoniae (CS-hvKp) strains KPLSN and KPLSX were isolated from the knee joint pus and blood specimens of the patient for further investigations. Whole genome sequencing revealed that KPLSN and KPLSX were highly homologous (SNPs<10) and belonging to ST412/K57. The minimum inhibitory concentration and minimum bactericidal concentration under biofilm values of meropenem in KPLSN and KPLSX were significantly higher than planktonic state (>128 mg/L versus 0.25 mg/L, P<0.0001). These two strains had high biofilm formation ability, and fluorescence staining experiments results showed that they were not easily killed by meropenem in the biofilm state. KPLSN and KPLSX showed high capsular production and were confirmed with high virulence through experiments with the Galleria mellonella and BALB/c mice abdominal infection model. The persistent symptoms may be due to enhanced biofilm and capsule formation. Global ST412 strains phylogenetic analysis showed their evolution towards higher virulence and resistance. It emphasizes the critical need for judicious antibiotic use and novel therapeutic approaches to combat special infections caused by these pathogens.

Effect of shell composition on watertightness and mechanical performance of cement-based capsules used as self-healing additives of cement

The aim of this work is the development of cementitious macro-capsules for self-healing cement and concrete materials. Emphasis is placed on shell properties, including size, thickness, strength, and volume to active component ratio. This enhancement is aimed at protecting the healing agent and ensuring adequate reactivity upon crack formation, surpassing survivability considerations. To this direction, core/shell particles have been produced following the pan-coating method, while different types and concentrations of setting acceleration solutions for the shell stabilization were studied. The formation of core-shell capsules encompasses the formation a spherical core through agglomeration, followed by simultaneous spraying of cement powder and a setting acceleration solution for the shell formation, under continuous rotation. The microstructural characteristics of the shell were studied through scanning electron microscopy (SEM), while the reactivity of the protected core (reactive agent) inside the hardened mortar mixtures was evaluated using thermogravimetric analysis (TGA). Moreover, the crushing load of the capsules under compression and their survivability during mixing process were examined and interpreted in relation to their diameter, circularity, and shell thickness.The results revealed the ability of the encapsulation methodology proposed to tailor the shell properties and modify the capsule properties so as satisfy the requirements of different applications. The use of setting accelerators during shell formation proved essential for enhancing the density and the strength of the shell layer. As a consequence, this leads to macro-scale capsules with elevated survivability rate and core reactivity.

Efficacy and Safety of Cell-Assisted Acellular Adipose Matrix Transfer for Volume Retention and Regeneration Compared to Hyaluronic Acid Filler Injection.

Cell-assisted acellular adipose matrix (AAM) transfer is a novel technique for soft tissue volume restoration, where AAM acts as a scaffold for tissue proliferation and promotes host cell migration, vascularization, and adipogenesis. This study aimed to evaluate the efficacy and safety of in vivo cell-assisted AAM transfer compared to hyaluronic acid (HA) filler injection. Human adipose tissue was used to manufacture AAM, and murine adipose-derived stem cells (ASCs) were prepared. Nude mice were divided into four groups: AAM transfer (AT), ASC-assisted AAM transfer (CAT), HA filler injection (HI), and ASC-assisted HA filler injection (CHI). Eight weeks post-transfer, in vivo graft volume/weight, histology, and gene expression were analyzed to assess efficacy and safety. The AAM retained its three-dimensional scaffold structure without cellular components. AT/CAT showed lower volume retention than HA/CHA; however, CAT maintained a similar volume to HA. Histologically, adipogenesis and collagen formation were increased in AT/CAT compared to HA/CHA, with CAT showing the highest levels. CAT also demonstrated superior angiogenesis, adipogenesis, and gene expression (Vegf and Pparg), along with lower Il-6 expression, higher Il-10 expression, and reduced capsule formation, indicating better biocompatibility. Cell-assisted AAM transfer is a promising technique for volume retention and tissue regeneration, offering a safe and effective alternative to HA filler injections. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

In vitro capsule or biofilm formation of Streptococcus uberis and bacteriological cure of bovine mastitis.

The relationship between the in vitro detected virulence factors biofilm and capsule formation of Streptococcus (S.) uberis isolates of clinical mastitis in dairy cows and the bacteriological cure rate after antibiotic therapy was investigated in order to better understand the importance of these virulence factors for the bacteriological cure rate. A total of 111 clinical mastitis (CM) cases were collected, in which S. uberis was bacteriologically detected. All mastitis cases were treated in accordance with the approval conditions of the antibiotic udder tubes used. Individual cow information including age, number of lactations, current lactation mastitis and antimicrobial treatment received was recorded. The microtiter plate test was used to detect biofilm formation and Anthony capsule staining was used to detect capsular capacity. Statistical analyses were performed to characterize the correlation between in vitro virulence factors and bacteriological cure (BC) rate. 30.5% (n=29) of the S. uberis isolates of bacteriologically cured cases and 34.5% (n=10) of the isolates of bacteriologically non-cured mastitis cases were found to have the ability to produce capsules in vitro. 70.7% (n=58) of the S. uberis isolates from bacteriologically cured mastitis cases had the ability to produce biofilm in vitro, whereas 58.6% (n=17) of the isolates of non-cured mastitis cases showed ability in producing biofilm. No correlation was found between the in vitro ability of S. uberis to form capsules and biofilms and the BC rate after antibiotic treatment of bovine mastitis. The present work has shown that the investigated in vitro virulence factors are not associated with the BC after antibiotic therapy. Further studies on the role of S. uberis virulence factors are needed to complete the missing knowledge on the difficulties in curing S. uberis mastitis. This study is of great clinical relevance since it enhances the understanding of the occurrence of BC in S. uberis mastitis cases. The investigated virulence factors are often addressed as possible reasons for therapy failure, although respective scientific studies are missing.

Whole genome sequencing reveals antibiotic resistance pattern and virulence factors in Klebsiella quasipneumoniae subsp. similipneumoniae from Hospital wastewater in South-West, Nigeria.

Klebsiella quasipneumoniae is a distinct species from K. pneumoniae, even though it is sometimes mistaken phenotypically for the latter in clinical situations. K. quasipneumoniae is a pathogen and this study aims at understanding the genomic antibiotic resistance and virulence characteristics of Klebsiella quasipneumoniae subsp. similipneumoniae (B105 strain) isolated from tertiary hospital wastewater and the potential risks associated with its environmental spread.The Illumina platform was used for whole-genome sequencing (WGS), the generated raw reads (de novo) was assembled using RAPT NCBI, while other standardized bioinformatics tools were utilized to validate and examine the landscape of the genome’s antibiotic resistance and virulence factors. The K. quasipneumoniae subsp. similipneumoniae (B105 strain), belonged to sequence type 1422 and was resistant to ampicillin, amoxicillin-clavulanic acid, ceftazidime, cefepime, meropenem, tetracycline, but susceptible to gentamicin. The annotated genome acknowledged the presence of blaOKP-B-2, ompK 36, fosA5, oqxAB, virulence genes responsible for capsule formation, lipopolysaccharide, iron uptake aerobactin (iutA), salmochelins (iroE, iroN), enterobactin siderophore, efllux pump (acrA, acrB) adherence, (mrkC, mrkD, and fimD) and two plasmids replicon IncFIB(K) and IncR. The study resonates the inadequacy of conventional microbiological identification methods to distinguish K. pneumoniae and K. quasipneumoniae and at the same time heightens the importance of using a genomic platform to extol the identity of K. quasipneumoniae subsp. similipneumoniae strain. Furthermore, the peculiarities of the acquired antimicrobial resistance and virulence genes, in this strain, are a potential risk to the environment.

Relationship between capsule production and biofilm formation by Mannheimia haemolytica, and establishment of a poly-species biofilm with other Pasteurellaceae

Mannheimia haemolytica is one of the bacterial agents responsible for bovine respiratory disease (BRD). The capability of M. haemolytica to form a biofilm may contribute to the development of chronic BRD infection by making the bacteria more resistant to host innate immunity and antibiotics. To improve therapy and prevent BRD, a greater understanding of the association between M. haemolytica surface components and biofilm formation is needed. M. haemolytica strain 619 (wild-type) made a poorly adherent, low-biomass biofilm. To examine the relationship between capsule and biofilm formation, a capsule-deficient mutant of wild-type M. haemolytica was obtained following mutagenesis with ethyl methanesulfonate to obtain mutant E09. Loss of capsular polysaccharide (CPS) in mutant E09 was supported by transmission electron microscopy and Maneval's staining. Mutant E09 attached to polyvinyl chloride plates more effectively, and produced a significantly denser and more uniform biofilm than the wild-type, as determined by crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy with COMSTAT analysis. The biofilm matrix of E09 contained predominately protein and significantly more eDNA than the wild-type, but not a distinct exopolysaccharide. Furthermore, treatment with DNase I significantly reduced the biofilm content of both the wild-type and E09 mutant. DNA sequencing of E09 showed that a point mutation occurred in the capsule biosynthesis gene wecB. The complementation of wecB in trans in mutant E09 successfully restored CPS production and reduced bacterial attachment/biofilm to levels similar to that of the wild-type. Fluorescence in-situ hybridization microscopy showed that M. haemolytica formed a poly-microbial biofilm with Histophilus somni and Pasteurella multocida. Overall, CPS production by M. haemolytica was inversely correlated with biofilm formation, the integrity of which required eDNA. A poly-microbial biofilm was readily formed between M. haemolytica, H. somni, and P. multocida, suggesting a mutualistic or synergistic interaction that may benefit bacterial colonization of the bovine respiratory tract.

In Vitro Analysis of Tandem Peptides from Human CD5 and CD6 Scavenger Receptors as Potential Anti-Cryptococcal Agents.

Cryptococcus neoformans is included in the World Health Organization fungal priority pathogen list, complied to expedite improved research and public-health interventions. The limited number of available antifungal drugs, their associated toxicity, and the emergence of drug-resistant strains make the development of new therapeutic strategies mandatory. Pattern-recognition receptors (PRRs) from the host's innate immune system constitute a potential source of new antimicrobial agents. CD5 and CD6 are lymphoid members of the ancient scavenger receptor cysteine-rich superfamily (SRCR-SF) which bind pathogen-associated molecular patterns (PAMPs) of fungal and bacterial origin. Evidence supports the concept that such binding maps to 11-mer sequences present in each of their three SRCR extracellular domains. Herein, we have designed synthetic peptides containing tandems of such 11-mer sequences (namely CD5-T and CD6-T) and analyzed their C. neoformans-binding properties in vitro. Our results show both inhibitory effects on fungal growth and an ability to impact capsule formation and titanization, two critical virulence factors of C. neoformans involved in immune evasion. These effects hold promise for CD5-T and CD6-T peptides as single or adjuvant therapeutic agents against cryptococcosis.

Tri‐ and Hexadentate Poly‐Lewis Acids – Attempts to Unravel the Complex Dynamics of Cage and Capsule Formation in Solution

AbstractTwo tri‐ and two hexadentate poly‐Lewis acids (PLAs) with calyx‐like structures of C3 symmetry containing aluminum‐ and boron‐containing Lewis acidic functions were prepared by tin‐metal exchange reactions. The triply hydrosilylated [12]annulene served as basic framework. It forms a calyx‐like structure by the stereo‐ and regioselective attachment of three SiMeCl2 groups to the planar [12]annulene. The PLA precursors were generated by attaching three or six trimethylstannylethynyl groups to the silicon atoms. Lewis acid functions were introduced using the reagents bis‐(bis(trimethylsilyl)methyl)aluminium hydride (HAl[CH(SiMe3)2]2) and catecholatochloroborane (ClBCat). The complexation behavior of the PLAs towards different Lewis bases was investigated by NMR. Bases included pyridine, polydentate nitrogen‐ and phosphorus‐containing bases. Additionally, three molecules of a bidentate phosphorus‐containing base were captured with hexadentate PLAs. Diffusion NMR experiments provided insight into the aggregation processes: some of the adducts had a significantly larger volume than expected, indicating the formation of larger adducts than the expected 1 : 1 adduct, including larger 2 : 2 adduct cages. The distances between the Lewis acid units and the steric requirement of the attached substituents determine the complexation behavior of the PLAs. Thus, the weak Lewis acidic BCat units show no (tridentate case) or a strong (hexadentate case) interaction with PMe2‐containing bases, if they can act cooperatively.

Impact of nitric oxide donors on capsule, biofilm and resistance profiles of Klebsiella pneumoniae

Klebsiella pneumoniae is considered to be a critical public health threat due to its ability to cause fatal, multi-drug-resistant infections in the bloodstream and key organs. The polysaccharide-based capsule layer that shields K. pneumoniae from clearance via innate immunity is a prominent virulence factor. K. pneumoniae also forms biofilms on biotic and abiotic surfaces. These biofilms significantly reduce penetration by, and antibacterial activity from, traditional antibiotics. Nitric oxide (NO), an endogenous molecule involved in the innate immune system, is equally effective at eradicating bacteria but without engendering resistance. This study investigated the effects of NO-releasing small molecules capable of diverse release kinetics on the capsule and biofilm formation characteristics of multiple K. pneumoniae strains. The use of NO donors with moderate and extended NO-release properties (i.e., half-life >1.8 h) inhibited bacterial growth. Additionally, treatment with NO decreased capsule mucoviscosity in K. pneumoniae strains that normally exhibit hypermucoviscosity. The NO donors were also effective against K. pneumoniae biofilms at the same minimum biocidal concentrations that eliminated planktonic bacteria, while meropenem showed little antibacterial action in the same experiments. These results represent the first account of exogenous NO affecting biomarkers involved in K. pneumoniae infections, and may therefore inform future development of NO-based therapeutics for treating such infections.

Capsule Formation Mechanisms in Interfacially Initiated Macroporous Hydrogels to Tailor Microstructures for the Encapsulation of Living Bacteria

Capsule Formation Mechanisms in Interfacially Initiated Macroporous Hydrogels to Tailor Microstructures for the Encapsulation of Living Bacteria

Ultrasound Control of Pickering Emulsion-Based Capsule Preparation.

Capsules with microparticle shells became of great interest due to their potential in many fields. Those capsules can be fabricated at high temperatures from particle-stabilized emulsions (Pickering emulsions) by sintering together particles that cover droplets. One of the problems with such an approach is accurately controlling whether particles are already sintered and creating the rigid capsule shell of a capsule. Here, we propose using a non-destructive ultrasound method for monitoring Pickering emulsion-based capsules prepared using heating under an alternating magnetic field. The polyethylene microparticles that were responsive to temperatures higher than 112 °C were used as droplet stabilizers together with iron oxide nanoparticles. During the coalescence of the droplets, facilitated by an external electric field, the ultrasonic attenuation increased, giving evidence that the ultrasound method detects structural changes in Pickering emulsions. The main change was the difference in the droplets' size, which was also observed via optical microscopy. The attenuation of ultrasound increased even more when measured after magnetic heating for the same concentration of particle stabilizers. Simultaneously, the values of ultrasonic velocity did not exhibit similar variety. The results show that the values of the attenuation coefficient can be used for a quantitative evaluation of the capsule formation process.

Immunocompatible elastomer with increased resistance to the foreign body response

Polymeric elastomers are extensively employed to fabricate implantable medical devices. However, implantation of the elastomers can induce a strong immune rejection known as the foreign body response (FBR), diminishing their efficacy. Herein, we present a group of immunocompatible elastomers, termed easy-to-synthesize vinyl-based anti-FBR dense elastomers (EVADE). EVADE materials effectively suppress the inflammation and capsule formation in subcutaneous models of rodents and non-human primates for at least one year and two months, respectively. Implantation of EVADE materials significantly reduces the expression of inflammation-related proteins S100A8/A9 in adjacent tissues compared to polydimethylsiloxane. We also show that inhibition or knockout of S100A8/A9 leads to substantial attenuation of fibrosis in mice, suggesting a target for fibrosis inhibition. Continuous subcutaneous insulin infusion (CSII) catheters constructed from EVADE elastomers demonstrate significantly improved longevity and performance compared to commercial catheters. The EVADE materials reported here may enhance and extend function in various medical devices by resisting the local immune responses.

Layer-by-Layer Assembling and Capsule Formation of Polysaccharide-Based Polyelectrolytes Studied by Whispering Gallery Mode Experiments and Confocal Laser Scanning Microscopy

The layer-by-layer (LbL) assembling of oppositely charged polyelectrolytes was studied using semi-synthetic polysaccharide derivatives, namely the polycations 6-aminoethylamino-6-deoxy cellulose (ADC) and cellulose (2-(ethylamino)ethylcarbamate (CAEC), as well as the polyanion cellulose sulfate (CS). The synthetic polymers poly(allylamine) (PAH) and poly(styrene sulfonate) (PSS) were employed as well for comparison. The stepwise adsorption process was monitored by whispering gallery mode (WGM) experiments and zeta-potential measurements. Distinct differences between synthetic- and polysaccharide-based assemblies were observed in terms of the quantitative adsorption of mass and adsorption kinetics. The LbL-approach was used to prepare µm-sized capsules with the aid of porous and non-porous silica particle templates. The polysaccharide-based capsule showed a switchable permeability that was not observed for the synthetic polymer materials. At ambient pH values of 7, low-molecular dyes could penetrate the capsule wall while no permeation occurred at elevated pH values of 8. Finally, the preparation of protein-loaded LbL-capsules was studied using the combination of CAEC and CS. It was shown that high amounts of protein (streptavidin and ovomucoid) can be encapsulated and that no leaking or disintegration of the cargo macromolecules occurred during the preparation step. Based on this work, potential use in biomedical areas can be concluded, such as the encapsulation of bioactive compounds (e.g., pharmaceutical compounds, antibodies) for drug delivery or sensing purposes.