Eco-friendly chitosan microspheres as a novel one-step sorbent for the rapid purification and determination of pesticides and veterinary drug multi-residues in aquatic products with HPLC-MS/MS.

A modified QuEChERS method was developed to determine multi-class pesticide and veterinary residues in aquatic products. Chitosan microspheres were conveniently synthesized and utilized as the cleanup adsorbent in the QuEChERS procedure, showcasing rapid filtration one-step pretreatment ability for the determination of drug multi-residues in aquatic products. Compared to conventional synthetic sorbents, chitosan microspheres not only have good purification performance, but also have renewable and degradable properties. This novel sorbent worked well in the simultaneous determination of 95 pesticides and veterinary drug residues in aquatic products after being combined with an improved one-step vortex oscillating cleanup method. We achieved recoveries ranging from 64.0% to 115.9% for target drugs in shrimp and fish matrix. The limits of detection and quantification were 0.5-1.0 and 1.0-2.0 µg kg-1, respectively. Notably, hydrocortisone was detected with considerable frequency and concentration in the tested samples, underscoring the necessity for stringent monitoring of this compound in aquatic products.

Molecularly Imprinted Microspheres in Active Compound Separation from Natural Product.

Molecularly Imprinted Microspheres (MIMs) or Microsphere Molecularly Imprinted Polymers represent an innovative design for the selective extraction of active compounds from natural products, showcasing effectiveness and cost-efficiency. MIMs, crosslinked polymers with specific binding sites for template molecules, overcome irregularities observed in traditional Molecularly Imprinted Polymers (MIPs). Their adaptability to the shape and size of target molecules allows for the capture of compounds from complex mixtures. This review article delves into exploring the potential practical applications of MIMs, particularly in the extraction of active compounds from natural products. Additionally, it provides insights into the broader development of MIM technology for the purification of active compounds. The synthesis of MIMs encompasses various methods, including precipitation polymerization, suspension polymerization, Pickering emulsion polymerization, and Controlled/Living Radical Precipitation Polymerization. These methods enable the formation of MIPs with controlled particle sizes suitable for diverse analytical applications. Control over the template-to-monomer ratio, solvent type, reaction temperature, and polymerization time is crucial to ensure the successful synthesis of MIPs effective in isolating active compounds from natural products. MIMs have been utilized to isolate various active compounds from natural products, such as aristolochic acids from Aristolochia manshuriensis and flavonoids from Rhododendron species, among others. Based on the review, suspension polymerization deposition, which is one of the techniques used in creating MIPs, can be classified under the MIM method. This is due to its ability to produce polymers that are more homogeneous and exhibit better selectivity compared to traditional MIP techniques. Additionally, this method can achieve recovery rates ranging from 94.91% to 113.53% and purities between 86.3% and 122%. The suspension polymerization process is relatively straightforward, allowing for the effective control of viscosity and temperature. Moreover, it is cost-effective as it utilizes water as the solvent.

Target-specific affinity separation of the bioactive compounds from herbal extract using the spin column packed with the immobilized protein microspheres prior to LC-MS analysis.

Excellent pretreatments before instrumental analysis are critical for separation and determination of target compounds for discovery of new drugs from herb medicines. We developed a rapid and highly-selective method to separate the bioactive compounds from herbal extract using protein affinity-selection spin column, which was packed with the new sorbent materials from integrating the recombinant ß2-adrenoceptor (ß2-AR) directly out of cell lysates onto the surface of microspheres. Protein affinity-selection spin column was placed in a centrifugal tube, where after the non-specific binders were released to the filtrate under the operational centrifugation, the specific binders on the spin column were cleaned with a washing solvent for LC-MS analysis. The known agonists of ß2-AR were retained/released on protein affinity-selection spin column but not on control column, demonstrating the method with good recovery (79.4∼95.7 %) and high repeatability (RSD < 3.5 %). The adsorption features of three ligands on the spin column were described best by Prism saturation binding model, and the high-affinity binding and the large binding capacity of the spin column make it feasible to trap the trace analytes effectively. It was applied in separating bioactive compounds from Alstoniae Scholaris extract, two of which were identified as picrinine and oleanolic acid in combination with LC-MS and verified as the potential agonists towards ß2-AR though molecular docking and cell experiments. Our study demonstrated that, the spin column with the immobilized protein sorbents in the centrifugal filter device represents a promising tool, enabling rapid and target-specific affinity separation of the bioactive compounds from herbal extract.

Comparative Assessment of the Influence of Embolizing Agents on the Adrenal Parenchyma.

A comparative analysis of morphological and functional changes in the adrenal glands after embolization of supplying arteries with Lifepearl microspheres (100±25 µm; Terumo) and with a solution of polidocanol (Aethoxysklerol, Kreussler Pharma) was performed in male Vietnamese Lop-Bellied pigs (n=20). The introduction of the microspheres into the arterial bed did not affect the adrenal parenchyma. However, the injection of the liquid sclerosing agent caused foci of productive inflammation leading to the formation of sclerotic tissue and reduction of the volume of glandular tissue. Administration of the sclerosant was accompanied by arterial hypotension, an indirect indication of a decrease in vasoactive hormone production by the adrenal cortex. These findings suggest that polidocanol can be used as an embolization agent for hyperplastic diseases of the adrenal cortex.

Long-Term Exposure to Polystyrene Microspheres and High-Fat Diet-Induced Obesity in Mice: Evaluating a Role for Microbiota Dysbiosis.

BACKGROUND: Microplastics (MPs) have become a global environmental problem, emerging as contaminants with potentially alarming consequences. However, long-term exposure to polystyrene microspheres (PS-MS) and its effects on diet-induced obesity are not yet fully understood. OBJECTIVES: We aimed to investigate the effect of PS-MS exposure on high-fat diet (HFD)-induced obesity and underlying mechanisms. METHODS: In the present study, C57BL/6J mice were fed a normal diet (ND) or a HFD in the absence or presence of PS-MS via oral administration for 8 wk. Antibiotic depletion of the microbiota and fecal microbiota transplantation (FMT) were performed to assess the influence of PS-MS on intestinal microbial ecology. We performed 16S rRNA sequencing to dissect microbial discrepancies and investigated the dysbiosis-associated intestinal integrity and inflammation in serum. RESULTS: Compared with HFD mice, mice fed the HFD with PS-MS exhibited higher body weight, liver weight, metabolic dysfunction-associated steatotic liver disease (MASLD) activity scores, and mass of white adipose tissue, as well as higher blood glucose and serum lipid concentrations. Furthermore, 16S rRNA sequencing of the fecal microbiota revealed that mice fed the HFD with PS-MS had greater α-diversity and greater relative abundances of Lachnospiraceae, Oscillospiraceae, Bacteroidaceae, Akkermansiaceae, Marinifilaceae, Deferribacteres, and Desulfovibrio, but lower relative abundances of Atopobiaceae, Bifidobacterium, and Parabacteroides. Mice fed the HFD with PS-MS exhibited lower expression of MUC2 mucin and higher levels of lipopolysaccharide and inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1ß, and IL-17A] in serum. Correlation analyses revealed that differences in the microbial flora of mice exposed to PS-MS were associated with obesity. Interestingly, microbiota-depleted mice did not show the same PS-MS-associated differences in Muc2 and Tjp1 expression in the distal colon, expression of inflammatory cytokines in serum, or obesity outcomes between HFD and HFD + PS-MS. Importantly, transplantation of feces from HFD + PS-MS mice to microbiota-depleted HFD-fed mice resulted in a lower expression of mucus proteins, higher expression of inflammatory cytokines, and obesity outcomes, similar to the findings in HFD + PS-MS mice. CONCLUSIONS: Our findings provide a new gut microbiota-driven mechanism for PS-MS-induced obesity in HFD-fed mice, suggesting the need to reevaluate the adverse health effects of MPs commonly found in daily life, particularly in susceptible populations. https://doi.org/10.1289/EHP13913.

Regulation of macroporous cellulose microspheres via phase separation force induced by carbon nanotubes doping for enhanced protein adsorption.

The burgeoning requirement for purified biomacromolecules in biopharmaceutical industry has amplified the exigency for advanced chromatographic separation techniques. Herein, macroporous cellulose microspheres (CCMs) with micron-sized pores are produced by a facile regulation via carbon nanotubes (CNTs). In this strategy, the incorporation of CNTs breaks the homogeneous regeneration of the cellulose, thus providing anisotropic phase force to produce macropores. The CCMs have manifested a faster mass transfer rate and more available adsorption sites owing to well-defined macropores (2.69 ± 0.57 µm) and high specific surface area (147.47 m2 g-1). Further, CCMs are functionalized by quaternary ammonium salts (GTAc-CCMs) and utilized as anion adsorbents to adsorb pancreatic kininogenase (PK). The prepared GTAc-CCMs show rapid adsorption kinetics for PK at pH 6.0, reaching 90 % equilibrium within 60 min. Also, GTAc-CCMs for PK exhibit high adsorptive capacity (632.50 mg g-1), excellent recyclability (> 80 % removal amount after 10 cycles) and selectivity especially at pH 6.0. Notably, the GTAc-CCMs have been successfully applied in a fixed-bed chromatography process, indicating their potential as an effective chromatographic medium for rapid separation of biomacromolecules.

Resorbable Microspheres versus Trisacryl Gelatin Microspheres for Uterine Artery Embolization: A Randomized Controlled Trial.

Background There are insufficient data comparing resorbable microspheres (RMs) with permanent trisacryl gelatin microspheres (TAGMs) for uterine artery embolization (UAE). Purpose To compare therapeutic efficacy and clinical outcomes in participants with symptomatic fibroids after UAE with RMs or TAGMs. Materials and Methods This randomized controlled trial included participants undergoing UAE for symptomatic fibroids at a single institution (from May 2021 to May 2023). Participants were randomized one-to-one to undergo UAE with either RMs or TAGMs. Numeric rating scale pain scores and cumulative fentanyl consumption were assessed for 24 hours after undergoing UAE. Anti-Mullerian hormone was measured to assess effects of UAE on ovarian function. MRI was performed before and 3 months after UAE to evaluate fibroid necrosis and uterine artery recanalization. Repeated variables such as pain were analyzed using Mann-Whitney U test with post hoc Bonferroni correction. Results Sixty female participants (mean age, 45.7 years ± 3.6 [SD]) completed the study, with 30 in each group. No evidence of a difference in pain scores was observed between groups (P > .99). Moreover, there was no evidence of a difference in the total fentanyl consumption at 24 hours after UAE between groups (median: RMs, 423 [IQR, 330-530] vs TAGMs, 562 [IQR, 437-780]; P = .15). Serum anti-Mullerian hormone 3 months after UAE showed no evidence of a difference between groups (RMs vs TAGMs, 0.71 ng/mL ± 0.73 vs 0.49 ng/mL ± 0.45, respectively; P = .09). No evidence of a difference in the rate of complete necrosis of the dominant fibroid was observed between groups (97% [29 of 30] for both groups; P > .99). The rate of uterine artery recanalization was higher in RM versus TAGM groups (70% [21 of 30] vs 17% [five of 30], respectively; P < .001). Conclusion UAE with RMs, compared with UAE with TAGMs, showed no evidence of a difference in terms of therapeutic effectiveness or postprocedural pain scores in participants with symptomatic fibroids. Clinical trial registration no. NCT05086770 © RSNA, 2024 See also the editorial by Spies in this issue.

Immobilization of HRP enzyme on polymeric microspheres and its use in decolourisation of organic dyes.

In this study, horseradish peroxidase (HRP) enzyme was immobilized on Pd(II) containing polymeric microspheres by adsorption method and used for the decolourisation of Methyl Orange (MO) and Rhodamine B (RB) dyes. The synthesized microspheres were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM/EDX), Thermal Gravimetric Analysis (TGA). The effects of pH, dye concentration, temperature, and H2O2 concentration on the decolourisation of MO and RB were determined. According to the results of various parameters studied, when 2-AEPS-napht-HRP support was used, MO and RB were biodegraded to 69.72% and 80.65%, respectively, within 60 min. When 2-AEPS-napht-Pd-HRP support was used, MO and RB were biodegraded to 58.35% and 90.81%, respectively, under optimum conditions. When the reproducibility results of the immobilized supports were examined, it was observed that they remained efficient during the first five reusability cycles and even reached 65% decolourisation efficiency after the 9th reuse. The immobilized enzyme (2AEPS-npht-HRP and 2AEPS-npht-Pd-HRP) showed remarkable resistance to higher temperatures compared to the free enzyme.

Artificial kinetochore beads establish a biorientation-like state in the spindle.

Faithful chromosome segregation requires biorientation, where the pair of kinetochores on the chromosome establish bipolar microtubule attachment. The integrity of the kinetochore, a macromolecular complex built on centromeric DNA, is required for biorientation, but components sufficient for biorientation remain unknown. Here, we show that tethering the outer kinetochore heterodimer NDC80-NUF2 to the surface of apolar microbeads establishes their biorientation-like state in mouse cells. NDC80-NUF2 microbeads align at the spindle equator and self-correct alignment errors. The alignment is associated with stable bipolar microtubule attachment and is independent of the outer kinetochore proteins SPC24-SPC25, KNL1, the Mis12 complex, inner kinetochore proteins, and Aurora. Larger microbeads align more rapidly, suggesting a size-dependent biorientation mechanism. This study demonstrates a biohybrid kinetochore design for synthetic biorientation of microscale particles in cells.

Lactobacillus casei displaying MCP2α and FlaC delivered by PLA microspheres effectively enhances the immune protection of largemouth bass (Micropterus salmoides) against LMBV infection.

Largemouth bass ranavirus (LMBV) seriously affects the development of largemouth bass (Micropterus salmoides) industry and causes huge economic losses. Oral vaccine can be a promising method for viral disease precaution. In this study, MCP2α was identified as a valuable epitope region superior to MCP and MCP2 of LMBV by neutralizing antibody experiments. Then, recombinant Lactobacillus casei expressing the fusion protein MCP2αC (MCP2α as antigen, C represents flagellin C from Aeromonas hydrophila as adjuvant) on surface was constructed and verified. Further, PLA microsphere vaccine loading recombinant MCP2αC L. casei was prepared. The PLA microspheres vaccine were observed by scanning electron microscopy and showed a smooth, regular spherical surface with a particle size distribution between 100 and 200 µm. Furthermore, we evaluated the tolerance of PLA-MCP2αC vaccine in simulated gastric fluid and simulated intestinal fluid, and the results showed that PLA-MCP2αC can effectively resist the gastrointestinal environment. Moreover, the protective effect of PLA-MCP2αC against LMBV was evaluated after oral immunization and LMBV challenge. The results showed that PLA-MCP2αC effectively up-regulated the activity of serum biochemical enzymes (T-SOD, T-AOC, LZM, complement C3) and induced the mRNA expression of representative immune genes (IL-1ß, TNF-α, IFN-γ, MHC-IIα, Mx, IgM) in spleen and head kidney tissues. The survival rate of largemouth bass vaccinated with PLA-MCP2αC increased from 24 % to 68 %. Meanwhile, PLA-MCP2αC inhibited the LMBV burden in spleen, head kidney and liver tissues and attenuated tissue damage in spleen. These results suggested that PLA-MCP2αC can be used as a candidate oral vaccine against LMBV infection in aquaculture.

Comparisons between ingestion, rejection, and egestion of microbeads by burrowing clams, Meretrix meretrix and Paphia undulata: Implications for health risk of shellfish consumption.

Two burrowing clam species, namely Meretrix meretrix and Paphia undulata, were offered two sizes (small: 45-53 µm, and large: 106-125 µm) of fluorescent red polyethylene microbeads, and the ingestion (number of MPs in the body tissue and faeces) and rejection (number of MPs in pseudofaeces) of MPs investigated. Overall, MP beads ingested were 36 % more than those rejected. There was also a significant interaction between the size and fate of MPs. For both species, significantly more small beads were ingested than rejected, but there was no difference for the large beads. P. undulata ingested more MPs than M. meretrix and both species could depurate all the ingested MPs in 72 h, although a longer time was needed for the former species. The results can provide guidance on seafood selection and pre-treatment to minimize the number of MPs ingested by humans.

Microbubbles bound to drug-eluting beads enable ultrasound imaging and enhanced delivery of therapeutics.

Transarterial chemoembolization (TACE) is an image-guided minimally invasive treatment for liver cancer which involves delivery of chemotherapy and embolic material into tumor-supplying arteries to block blood flow to a liver tumor and to deliver chemotherapy directly to the tumor. However, the released drug diffuses only less than a millimeter away from the beads. To enhance the efficacy of TACE, the development of microbubbles electrostatically bound to the surface of drug-eluting beads loaded with different amounts of doxorubicin (0-37.5 mg of Dox/mL of beads) is reported. Up to 400 microbubbles were bound to Dox-loaded beads (70-150 microns). This facilitated ultrasound imaging of the beads and increased the release rate of Dox upon exposure to high intensity focused ultrasound (HIFU). Furthermore, ultrasound exposure (1 MPa peak negative pressure) increased the distance at which Dox could be detected from beads embedded in a tissue-mimicking phantom, compared with a no ultrasound control.

Revitalizing elixir with orange peel amplification of alginate fish oil beads for enhanced anti-aging efficacy.

The research introduces a novel method for creating drug-loaded hydrogel beads that target anti-aging, anti-oxidative, and anti-inflammatory effects, addressing the interconnected processes underlying various pathological conditions. The study focuses on the development of hydrogel beads containing anti-aging compounds, antioxidants, and anti-inflammatory drugs to effectively mitigate various processes. The synthesis, characterization and in vitro evaluations, and potential applications of these multifunctional hydrogel beads are discussed. A polymeric alginate-orange peel extract (1:1) hydrogel was synthesized for encapsulating fish oil. Beads prepared with variable fish oil concentrations (0.1, 0.3, and 0.5 ml) were characterized, showing no significant decrease in size i.e., 0.5 mm and a reduction in pore size from 23 to 12 µm. Encapsulation efficiency reached up to 98% within 2 min, with controlled release achieved upto 45 to 120 min with increasing oil concentration, indicating potential for sustained delivery. Fourier-transform infrared spectroscopy confirmed successful encapsulation by revealing peak shifting, interaction between constituents. In vitro degradation studies showed the hydrogel's biodegradability improved from 30 to 120 min, alongside anti-inflammatory, anti-oxidative, anti-collagenase and anti-elastase activities, cell proliferation rate enhanced after entrapping fish oil. In conclusion, the synthesized hydrogel beads are a promising drug delivery vehicle because they provide stable and effective oil encapsulation with controlled release for notable anti-aging and regenerative potential. Targeted delivery for inflammatory and oxidative stress-related illnesses is one set of potential uses. Further research may optimize this system for broader applications in drug delivery and tissue engineering.

Porous hollow microspheres based on industrial solid waste enhance biomethane recovery from corn straw.

The increasing production of industrial solid waste requires better disposal solutions. Porous hollow microspheres (PHM) are small inorganic materials with high surface area and adsorption capacity, but their potential for use in anaerobic digestion (AD) has not been explored. With PHM as additive, the effects of different industrial solid wastes (waste glass, steel slag, and fly ash) with different loadings (2 %-8 %), respectively, on the AD of corn straw were investigated in this study. The results showed that PHM could supplement trace elements and promote biofilm formation, which effectively shortened the lag period (25.00-60.87 %) and increased the methane yield (4.75 %-16.28 %). The 2 % PHM loading based on steel slag gave the highest methane yield (300.16 NmL/g VSadd). Microbial and PICRUSt2 analyses indicated that PHM enriched hydrolytic and acidogenic bacteria, increased the abundance of methanogenesis-related enzyme genes. This study provides a theoretical basis for the comprehensive utilization of coupled industrial and agricultural wastes.

Adsorption of ionic contaminants from complex water matrices by versatile chitosan-based beads.

Most adsorbents are currently restricted by their single function in pollutant removal from complex wastewater. Herein, we constructed a versatile chitosan-based adsorbent (MC-DA) by grafting amphoteric copolymers with high pH-responsiveness property, aiming at the removal of multiple ionic contaminants. Specifically, the surface charge and hydrophobicity/hydrophilicity of MC-DA can be finely tuned under different pH conditions. As a result, the effective adsorption of cationic methylene blue (MB) and anionic Acid Orange 7 (AO7) with capacities of 627.4 mg/g and 1146.8 mg/g were achieved respectively, superior to most reported materials. Regarding the characterization results, the adsorption mechanisms for MB adsorption were electrostatic and hydrophobic interactions, while the electrostatic attraction was the main driving force for AO7 adsorption. Apart from the versatile adsorption performance, high acid resistance (pH ≥ 2.0), good reusability and rapid separation property under an external magnetic field suggested MC-DA's promising environmental benefits and practical application potential in water remediation.

Prolonged Microcystis restraint through allelochemicals sustained-release microspheres regulated by carbon material (CM-AC@SM): Optimal formulation, characterization, effects and synergistic inhibition mechanisms.

The Microcystis blooms have caused serious damage to aquatic ecosystems. Microspheres containing allelochemicals with sustained-release properties have the potential to function as a cost-effective and environmentally friendly algaecide against M. aeruginosa. In the current investigation, we successfully optimized the synthesis of allelochemicals sustained-release microspheres regulated by carbon material (CM-AC@SM), which demonstrated a high embedding rate (90.17 %) and loading rate (0.65 %), with an accumulative release rate of 53.27 % on day 30. To investigate the sustained-release mechanism of CM-AC@SM, the sustained-release process of allelochemicals was determined using the Folin-Phenol method and the immersion behavior of the CM-AC@SM was characterized through SEM and XPS. Results showed that allelochemicals were released in the delayed-dissolution mode. In addition, to elucidate the synergistic mechanism of CM-AC@SM towards the inhibition of M. aeruginosa, this study comprehensively assessed the effects of allelochemicals, carbon material and CM-AC@SM on the morphology, antioxidant system activity and photosynthetic activity of M. aeruginosa. The findings indicated that allelochemicals and carbon material induced intracellular protein and nucleic acid leakage by increasing cell membrane permeability, disrupted the extracellular and intracellular morphology of algae, triggered peroxidative damage and restrained antioxidant system activity by stimulating the generation of reactive oxygen species. Simultaneously, the activity of photosystem II was inhibited by allelochemicals and carbon material, substantiated by the reduction in Fv/Fo and Fv/Fm ratios. Hence, CM-AC@SM shows promise in inhibiting M. aeruginosa, offering an efficient approach for the future large-scale control of harmful algal blooms (HABs).

Injectable and biodegradable collagen-chitosan microspheres for enhanced skin regeneration.

Skin aging is influenced by both external environmental factors and intrinsic biological mechanisms. Traditional microsphere implants aim to rejuvenate aging skin through collagen regeneration, yet their non-biodegradability and risk of granuloma formation often limit their effectiveness. In this study, we developed novel, injectable, highly bioactive, and degradable collagen-chitosan double-crosslinked composite microspheres for skin rejuvenation. The microspheres demonstrated excellent injectability, requiring an injection force of only 0.9 N, and significant biodegradability, effectively degraded in solutions containing phosphate buffer, type I collagenase, and pepsin. In addition, the microspheres exhibited excellent biocompatibility and bioactivity, significantly promoting the proliferation, adhesion, and migration of human foreskin fibroblast-1 (HFF-1) cells. In a photoaged mouse skin model, the implantation of microspheres significantly enhanced dermal density and skin elasticity while reducing transepidermal water loss. Importantly, the implant promoted the regeneration of collagen fibers. This study suggests that collagen-chitosan double-crosslinked composite microspheres hold significant potential for skin rejuvenation treatments.

A single domain antibody-based Luminex assay for the detection of SARS-CoV-2 in clinical samples.

Within the past decade, single domain antibodies (sdAbs) have been recognized as unique affinity binding reagents that can be tailored for performance in a variety of immunoassay formats. Luminex MagPlex color-coded magnetic microspheres provide a high-throughput platform that enables multiplexed immunoassays. We developed a MagPlex bead-based assay for the detection of SARS-CoV-2, using sdAbs against SARS-CoV-2 nucleocapsid (N) protein in which we engineered the sdAb capture reagents to orient them on the beads. The oriented sdAbs provided an increase in sensitivity over randomly oriented sdAbs for samples of N diluted in buffer, which also translated into better detection of SARS-CoV-2 in clinical samples. We assessed the specificity of the assay by examining seasonal coronavirus clinical samples. In summary, we provide a proof-of-concept that a bead-based assay using sdAbs to detect SARS-CoV-2 is feasible and future research combining it with other sdAb-coated beads that can detect other viruses may provide a useful diagnostic tool.

Microbead-Encapsulated Luminescent Bioreporter Screening of P. aeruginosa via Its Secreted Quorum-Sensing Molecules.

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that remains a prevalent clinical and environmental challenge. Quorum-sensing (QS) molecules are effective biomarkers in pinpointing the presence of P. aeruginosa. This study aimed to develop a convenient-to-use, whole-cell biosensor using P. aeruginosa reporters individually encapsulated within alginate-poly-L-lysine (alginate-PLL) microbeads to specifically detect the presence of bacterial autoinducers. The PLL-reinforced microbeads were prepared using a two-step method involving ionic cross-linking and subsequent coating with thin layers of PLL. The alginate-PLL beads showed good stability in the presence of a known cation scavenger (sodium citrate), which typically limits the widespread applications of calcium alginate. In media containing synthetic autoinducers-such as N-(3-oxo dodecanoyl) homoserine lactone (3-oxo-C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL), or the cell-free supernatants of planktonic or the flow-cell biofilm effluent of wild P. aeruginosa (PAO1)-the encapsulated bacteria enabled a dose-dependent detection of the presence of these QS molecules. The prepared bioreporter beads remained stable during prolonged storage at 4 and -80 °C and were ready for on-the-spot sensing without the need for recovery. The proof-of-concept, optical fiber-based, and whole-cell biosensor developed here demonstrates the practicality of the encapsulated bioreporter for bacterial detection based on specific QS molecules.