We have successfully prepared a highly sensitive sandwich nanosensor combined Fe3O4 and Au@ATP@Ag nanorods for histamine detection based on surface-enhanced Raman spectroscopy (SERS). The Fe3O4 beads ...with –COOH served as a capture part to enrich histamine. The Au@ATP@Ag core-shell nanorods functionalized with Nalpha,Nalpha-Bis(carboxymethyl)-l-lysine (AB-NTA) were then used to connect with the imidazolyl group of histamine, simultaneously the internal standard 4-aminothiophenol (4-ATP) in the core-shell structure was used as the SERS signal. PLS regression model based on concentration range 10−3-10−8mol/L showed a linear trend with R2 = 0.9907. Our new approach can quickly and reliably determine histamine in fish sample and RAW264.7 cell lysates. This protocol for histamine extraction and SERS analysis enables the development of ultra-sensitive method for histamine detection.
The scheme of histamine detection procedure. Display omitted
•We proposed Fe3O4/Au@ATP@Ag Nanorod sandwich structure integrated separation and detection for histamine in fish and RAW264.7.•Ultra-sensitive quantitative detection of histamine in 10−3-10−8 M and R2 = 0.9907.•Indirect measurement of histamine using internal standard 4-ATP signal of core-shell structure to avoid interference.•Fe3O4 quickly separate histamine from fish and RAW264.7 cell lysates by magnets without tedious procedures.
It has been recognized that a number of mechanisms mediating the health benefits of beneficial bacterial cells do require viability. However, new terms such as paraprobiotic or postbiotic have ...emerged to denote that non-viable microbial cells, microbial fractions, or cell lysates might also offer physiological benefits to the host by providing additional bioactivity.
This review provides an overview of the postbiotic concept, evidence of their health benefits and possible signaling pathways involved in their protective effects, as well as perspectives for applications in foods and pharmaceuticals.
Postbiotics refers to soluble factors (products or metabolic byproducts), secreted by live bacteria, or released after bacterial lysis, such as enzymes, peptides, teichoic acids, peptidoglycan-derived muropeptides, polysaccharides, cell surface proteins, and organic acids. These postbiotics have drawn attention because of their clear chemical structure, safety dose parameters, long shelf life and the content of various signaling molecules which may have anti-inflammatory, immunomodulatory, anti-obesogenic, antihypertensive, hypocholesterolemic, anti-proliferative, and antioxidant activities. These properties suggest that postbiotics may contribute, to the improvement of host health by improving specific physiological functions, even though the exact mechanisms have not been entirely elucidated.
•Postbiotics comprise metabolites and/or cell-wall components released by probiotics.•Postbiotics may, together with probiotics, improve host health.•The exact mechanisms of postbiotic bioactivities have not been fully elucidated.
β-Glucuronidase (GLU) is a hallmark enzyme for many malignant tumors, but bioluminescence (BL) probes that enable GLU imaging in vivo have not been reported. Herein, we rationally designed the BL ...probe Glc-Luc to address this issue. In vitro results demonstrated the specific responsiveness of Glc-Luc toward GLU with a calculated catalytic efficiency (k cat/K m) of 0.0109 μM–1 min–1 and a limit of detection (LOD) of 1.39 U/mL. Moreover, Glc-Luc rendered 3.1-fold and 15.9-fold higher BL intensities over the control groups in cell lysates and tumor-bearing mice, respectively. We anticipate that Glc-Luc could be further applied for the sensitive diagnosis of GLU-related diseases.
Ultrashort amphiphilic peptides, comprised of concise sequences of seven to four amino acids, display distinctive self-assembling behavior in physiological conditions, forming nanofiber-rich ...hydrogels with remarkably high water content (>99% w/w). The hydrogels are comprised of nanofibers and three-dimensional (3D) matrices mirroring the structure of the extracellular matrix. These hydrogels exhibit biocompatibility, creating a nurturing microenvironment that supports the viability, proliferation, and differentiation of stem cells.With the aim of enhancing the peptide scaffolds through integration with human platelet lysate while preserving the self-assembly process, this study explores the synergistic potential of ultrashort peptides and platelet lysates in guiding stem cell behavior within the hydrogel matrix.
In this investigation, a gelation test was performed to determine the minimum gelation concentration of the developed peptide. Additionally, we assessed cell viability, proliferation, as well as cell-cell and cell-matrix interactions. Through the strategic substitution of specific amino acids in the peptide sequence, we achieved the lowest reported minimum gelation concentration for self-assembling peptides, thereby expanding the range of their potential applications.By substituting specific amino acids in the peptide sequence, we successfully developed a peptide sequence that can form a nanofibrous hydrogel with the lowest documented minimum gelation concentration for self-assembling peptides, consequently broadening the scope of their potential applications. The peptide hydrogel formed a highly porous network of nanofibers with tunable mechanical properties. The 3D peptide culture supported the viability and growth of various cell types, including mesenchymal stromal cells. Additionally, it recapitulated cell-cell and cell-matrix interaction. Notably, the developed 3D culture system was able to support the growth of cells using media without serum supplementation. This attribute allows for the provision of a xeno-free 3D culture system that could be employed for advanced biomedical applications.This innovative framework shows potential in transforming the landscape of stem cell therapies by providing customized and dynamic settings. The integration of ultrashort peptides and platelet lysates in hydrogel design represents a significant stride toward advancing the field of stem cell-based therapies.
Rapid angiogenesis is one of the challenges in endodontic regeneration. Recently, tailored polymeric microsphere system that loaded pro-angiogenic growth factors (GFs) is promising in facilitating ...vascularization in dental pulp regeneration. In addition, the synergistic effect of multiple GFs is considered more beneficial, but combination usage of them is rather complex and costly. Herein, we aimed to incorporate human platelet lysate (PL), a natural-derived pool of multiple GFs, into gelatin methacrylate (GelMA) microsphere system (GP), which was further modified by Laponite (GPL), a nanoclay with efficient drug delivery ability. These hybrid microspheres were successfully fabricated by electrostatic microdroplet technique with suitable size range (180∼380 µm). After incorporation of the PL and Laponite with GelMA, the Young's modulus of the hybrid hydrogel increased up to about 3-fold and the swelling and degradation rate decreased simultaneously. The PL-derived GFs continued to release up to 28 days from both the GP and GPL microspheres, while the latter released relatively more slowly. What's more, the released GFs could effectively induce tubule formation of human umbilical endothelial cells (HUVECs) and also promote human dental pulp stem cells (hDPSCs) migration. Additionally, the PL component in the GelMA microspheres significantly improved the proliferation, spreading, and odontogenic differentiation of the encapsulated hDPSCs. As further verified by the subcutaneous implantation results, both of the GP and GPL groups enhanced microvascular formation and pulp-like tissue regeneration. This work demonstrated that PL-incorporating GelMA microsphere system was a promising functional vehicle for promoting vascularized endodontic regeneration.
Polymeric microsphere system loaded with pro-angiogenic growth factors (GFs) shows great promise for regeneration of vascularized dental pulp. Herein, we prepared a functional GelMA microsphere system incorporated with human platelet lysates (PL) and nanoclay Laponite by the electrostatic microdroplet method. The results demonstrated that the GelMA/PL/Laponite microspheres significantly improved the spreading, proliferation, and odontogenic differentiation of the encapsulated hDPSCs compared with pure GelMA microspheres. Moreover, they also enhanced microvascular formation and pulp-like tissue regeneration in vivo. This hybrid microsphere system has great potential to accelerate microvessel formation in regenerated dental pulp and other tissues.
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Nitroxide (NO) spin radicals are effective in characterizing structures, interactions and dynamics of biomolecules. The EPR applications in cell lysates or intracellular milieu require stable spin ...labels, but NO radicals are unstable in such conditions. We showed that the destabilization of NO radicals in cell lysates or even in cells is caused by NADPH/NADH related enzymes, but not by the commonly believed reducing reagents such as GSH. Maleimide stabilizes the NO radicals in the cell lysates by consumption of the NADPH/NADH that are essential for the enzymes involved in destabilizing NO radicals, instead of serving as the solo thiol scavenger. The maleimide treatment retains the crowding properties of the intracellular components and allows to perform long-time EPR measurements of NO labeled biomolecules close to the intracellular conditions. The strategy of maleimide treatment on cell lysates for the EPR applications has been demonstrated on double electron-electron resonance (DEER) measurements on a number of NO labeled protein samples. The method opens a broad application range for the NO labeled biomolecules by EPR in conditions that resemble the intracellular milieu.
AimsThe reliable classification of type A versus type B3 thymomas has prognostic and therapeutic relevance, but can be problematic due to considerably overlapping morphology. No immunohistochemical ...markers aiding in this distinction have been published so far.Methods and resultsWe identified and quantified numerous differentially expressed proteins using an unbiased proteomic screen by mass spectrometry in pooled protein lysates from three type A and three type B3 thymomas. From these, candidates were validated in a larger series of paraffin‐embedded type A and B3 thymomas. We identified argininosuccinate synthetase 1 (ASS1) and special AT‐rich sequence binding protein 1 (SATB1) as highly discriminatory between 34 type A and 20 type B3 thymomas (94% sensitivity, 98% specificity and 96% accuracy). Although not the focus of this study, the same markers also proved helpful in the diagnosis of type AB (n = 14), B1 (n = 4) and B2 thymomas (n = 10).ConclusionsMutually exclusive epithelial expression of ASS1 in 100% of type B3 thymomas and ectopic nuclear expression of SATB1 in 92% of type A thymomas support the distinction between type A and type B3 thymomas with 94% sensitivity, 98% specificity and 96% accuracy.
Highly heterogenous cancers, such as triple-negative breast cancer (TNBC), remain challenging immunotherapeutic targets. Herein, we describe the synthesis and evaluation of immunotherapeutic ...liposomal spherical nucleic acids (SNAs) for TNBC therapy. The SNAs comprise immunostimulatory oligonucleotides (CpG-1826) as adjuvants and encapsulate lysates derived from TNBC cell lines as antigens. The resulting nanostructures (Lys-SNAs) enhance the codelivery of adjuvant and antigen to immune cells when compared to simple mixtures of lysates with linear oligonucleotides both in vitro and in vivo, and reduce tumor growth relative to simple mixtures of lysate and CpG-1826 (Lys-Mix) in both Py230 and Py8119 orthotopic syngeneic mouse models of TNBC. Furthermore, oxidizing TNBC cells prior to lysis and incorporation into SNAs (OxLys-SNAs) significantly increases the activation of dendritic cells relative to their nonoxidized counterparts. When administered peritumorally in vivo in the EMT6 mouse mammary carcinoma model, OxLys-SNAs significantly increase the population of cytotoxic CD8+ T cells and simultaneously decrease the population of myeloid derived suppressor cells (MDSCs) within the tumor micro-environment, when compared with Lys-SNAs and simple mixtures of oxidized lysates with CpG-1826. Importantly, animals administered OxLys-SNAs exhibit significant antitumor activity and prolonged survival relative to all other treatment groups, and resist tumor rechallenge. Together, these results show that the way lysates are processed and packaged has a profound impact on their immunogenicity and therapeutic efficacy. Moreover, this work points toward the potential of oxidized tumor cell lysate-loaded SNAs as a potent class of immunotherapeutics for cancers lacking common therapeutic targets.
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