NIR-II fluorescent Ag2Se polystyrene beads in a lateral flow immunoassay to detect biomarkers for breast cancer.

Fluorescent lateral flow immunoassay (LFA), one tool in point of care testing (POCT) systems for breast cancer, has attracted attention because it is quick, simple, and convenient. However, samples and the constituent material exhibit autofluorescence in the visible region, which is a very large obstacle in the development of fluorescent LFAs. The autofluorescence of biological samples is scarcely found in the second near-infrared (NIR-II) range and samples scatter and absorb less NIR-II light than visible light. Here, we report an NIR-II QD-LFA platform using the NIR-II fluorescent Ag2Se quantum dots (QDs) with 1020 nm emission encapsulated into polystyrene beads as fluorescent probes. The NIR-II LFA platform was established to detect breast cancer tumour markers (CEA and CA153) within 15 min with a low limit of detection (CEA: 0.768 ng mL-1, CA153: 1.192 U mL-1), high recoveries (93.7% ~ 108.8%), and relative standard deviations (RSDs) of less than 10%. This study demonstrated the potential of NIR-II Ag2Se polystyrene beads as a fluorescent probe in LFA for rapid and accurate identification of biomarkers. They are suited for use in professional situations.

Wnt signalling in oral and maxillofacial diseases.

Wnts include more than 19 types of secreted glycoproteins that are involved in a wide range of pathological processes in oral and maxillofacial diseases. The transmission of Wnt signalling from the extracellular matrix into the nucleus includes canonical pathways and noncanonical pathways, which play an important role in tooth development, alveolar bone regeneration, and related diseases. In recent years, with the in-depth study of Wnt signalling in oral and maxillofacial-related diseases, many new conclusions and perspectives have been reached, and there are also some controversies. This article aims to summarise the roles of Wnt signalling in various oral diseases, including periodontitis, dental pulp disease, jaw disease, cleft palate, and abnormal tooth development, to provide researchers with a better and more comprehensive understanding of Wnts in oral and maxillofacial diseases.

Substrate stiffness promotes dentinogenesis via LAMB1-FAK-MEK1/2 signaling axis.

OBJECTIVES: In vivo, the principal function of mechanosensitive odontoblasts is to synthesize and secrete the matrix which then calcifies and forms reactive dentin after exposure to appropriate stimuli. This study aims to develop the influence of mechanical factors on dentinogenesis based on odontoblasts, which contribute to reparative dentin formation. METHODS: We fabricated polydimethylsiloxane with different stiffnesses and seeded 17IIA11 odontoblast-like cells on the substrates in different stiffnesses. Cell morphology was detected by scanning electron microscope, and the mineralization phenotype was detected by alkaline phosphatase staining and alizarin red staining, while expression levels of dentinogenesis-related genes (including Runx2, Osx, and Alp) were assayed by qPCR. To explore mechanism, protein distribution and expression levels were detected by immunofluorescent staining, Western blotting, and immunoprecipitation. RESULTS: In our results, during dentinogenesis, 17IIA11 odontoblast-like cells appeared better extension on stiffer substrates. The binding between LAMB1 and FAK contributed to converting mechanical stimuli into biochemical signaling, thereby controlling mitogen-activated protein kinase kinase 1/2 activity in stiffness-driven dentinogenesis. CONCLUSION: The present study suggests odontoblast behaviors can be directly regulated by mechanical factors at cell-material interfaces, which offers fundamental mechanism in remodeling cell microenvironment, thereby contributing to physiological phenomena explanation and tissue engineering progress.

Atomically referenced 1-GHz optical parametric oscillator frequency comb.

The visible to mid-infrared coverage of femtosecond optical parametric oscillator (OPO) frequency combs makes them attractive resources for high-resolution spectroscopy and astrophotonic spectrograph calibration. Such applications require absolute traceability and wide comb-tooth spacing, attributes which until now have remained unavailable from any single OPO frequency comb. Here, we report a 1-GHz Ti:sapphire pumped OPO comb whose repetition and offset frequencies are referenced to Rb-stabilised microwave and laser oscillators respectively. This technique simultaneously achieves fully stabilized combs from both the Ti:sapphire laser and the OPO with sub-MHz comb-tooth linewidths, multi-hour locking stability and without the need for super-continuum generation.

A smartphone-assisted photoelectrochemical POCT method via Z-scheme CuCo2S4/Fe3O4 for simultaneously detecting co-contamination with microplastics in food and the environment.

As emerging contaminants, microplastics threaten food and environmental safety. Dibutyl phthalate (DBP, released from microplastics) and benzo[a]pyrene (BaP, adsorbed on microplastics) coexisted in food and the environment, harming human health, requesting a sensitive and simultaneous testing method to monitor. To address current sensitivity, simultaneousness, and on-site portability challenges during dual targets in complex matrixes, CuCo2S4/Fe3O4 nanoflower was designed to develop a smartphone-assisted photoelectrochemical point-of-care test (PEC POCT). The carrier transfer mechanism in CuCo2S4/Fe3O4 was proven via density functional theory calculation. Under optimal conditions, the PEC POCT showed low detection limits of 0.126, and 0.132 pg/mL, wide linearity of 0.001-500, and 0.0005-50 ng/mL for DBP and BaP, respectively. The smartphone-assisted PEC POCT demonstrated satisfied recoveries (80.00%-119.63%) in real samples. Coherent results were recorded by comparing the PEC POCT to GC-MS (DBP) and HPLC (BaP). This novel method provides a practical platform for simultaneous POCT for food safety and environment monitoring.

Paxillin tunes the relationship between cell-matrix and cell-cell adhesions to regulate stiffness-dependent dentinogenesis.

Mechanical stiffness is recognized as a key physical factor and directs cell function via a mechanotransduction process, from extracellular physical cues to intracellular signaling cascades that affect transcriptional activity. Cells continually receive mechanical signals from both the surrounding matrix and adjacent cells. However, how mechanical stiffness cue at cell-substrate interfaces coordinates cell-cell junctions in guiding mesenchymal stem cell behaviors is poorly understood. Here, polydimethylsiloxane substrates with different stiffnesses were used to study mechanosensation/transduction mechanisms in controlling odontogenic differentiation of dental papilla cells (DPCs). DPC phenotypes (morphology and differentiation) changed in response to the applied force derived from stiff substrates. Significantly, higher expression of paxillin on stiffer substrates promoted DPC dentinogenesis. Upon treatment with siRNA to knockdown paxillin, N-cadherin increased mainly in the cytomembrane at the area of cell-cell contacts, whereas ß-catenin decreased in the nuclei. The result of a double luciferase reporter assay showed that stiffness promoted ß-catenin binding to TCF, which could coactivate the target genes associated with odontogenic differentiation, as evidenced by bioinformatics analysis. Finally, we determined that the addition of a ß-catenin inhibitor suppressed DPC mineralization in all the stiffness groups. Thus, our results indicated that a mechanotransduction process from cell-substrate interactions to cell-cell adhesions was required for DPC odontogenic differentiation under the stimulation of substrate stiffness. This finding suggests that stem cell fate specification under the stimulus of stiffness at the substrates is based on crosstalk between substrate interactions and adherens junctions, which provides an essential mechanism for cell-based tissue engineering.

Activin receptor-like kinase 3: a critical modulator of development and function of mineralized tissues.

Mineralized tissues, such as teeth and bones, pose significant challenges for repair due to their hardness, low permeability, and limited blood flow compared to soft tissues. Bone morphogenetic proteins (BMPs) have been identified as playing a crucial role in mineralized tissue formation and repair. However, the application of large amounts of exogenous BMPs may cause side effects such as inflammation. Therefore, it is necessary to identify a more precise molecular target downstream of the ligands. Activin receptor-like kinase 3 (ALK3), a key transmembrane receptor, serves as a vital gateway for the transmission of BMP signals, triggering cellular responses. Recent research has yielded new insights into the regulatory roles of ALK3 in mineralized tissues. Experimental knockout or mutation of ALK3 has been shown to result in skeletal dysmorphisms and failure of tooth formation, eruption, and orthodontic tooth movement. This review summarizes the roles of ALK3 in mineralized tissue regulation and elucidates how ALK3-mediated signaling influences the physiology and pathology of teeth and bones. Additionally, this review provides a reference for recommended basic research and potential future treatment strategies for the repair and regeneration of mineralized tissues.

A smartphone-powered photoelectrochemical POCT via Z-scheme Cu2O/Cu3SnS4 for dibutyl phthalate in the environmental and food.

As a major hazardous additive released from microplastics and nanoplastics, identifying dibutyl phthalate (DBP) in complex matrices attracts a growing concern in environmental monitoring and food safety. For the first time, Cu2O/Cu3SnS4 nanoflower is prepared and serves as the photoactive material which can be constructed as a smartphone-based photoelectrochemical (PEC) point-of-care test (POCT). Effectively matching energy levels between Cu2O and Cu3SnS4 accelerated the transfer of photogenerated electron-hole pairs, significantly improving the intelligent PEC POCT performance. The novel Cu2O/Cu3SnS4 has proven to be the Z-scheme heterojunction by density functional theory calculation. A competitive immunoassay has been realized on a Cu2O/Cu3SnS4 modified electrode, dramatically decreasing the photocurrent signal and enhancing POCT sensitivity. The smartphone has been used to record and transfer PEC results. Under optimal conditions, the PEC POCT exhibited a satisfying linear range (0.04-400 ng/mL) and a low detection limit of 7.94 pg/mL in real samples, together with excellent stability, repeatability, reproducibility and selectivity. The PEC POCT system provides good performance and practicability in determining DBP in water and edible oil samples. This proposal provides a practical strategy for the intelligent POCT for environment monitoring and food safety.

Tumor-triggered targeting ammonium bicarbonate liposomes for tumor multimodal therapy.

Tumor-triggered targeting ammonium bicarbonate (TTABC) liposomes were proposed to improve the uptake of ammonium bicarbonate (ABC) liposomes in tumor cells and retain their long circulation in vivo in our previous study. However, it must be solved how to precisely release the loaded drugs of the TTABC liposomes into tumor cells. In addition, synergistic multimodal therapy could result in better tumor treatment outcomes than monomodal chemotherapy. In the research, we prepared indocyanine green (ICG) and doxorubicin (DOX) encapsulated TTABC liposomes (ICG&DOX@TTABC) to achieve near-infrared (NIR) light-controlled chemo/photothermal/photodynamic multimodal therapy guided by fluorescence and photothermal imaging. In vitro and vivo studies show that ICG&DOX@TTABC can specifically accumulate in tumor tissues, effectively transform NIR light into local thermo-therapy, and have excellent anti-tumor ability without obvious side effects. ICG&DOX@TTABC could be promising for fluorescence and photothermal imaging-guided chemo/photothermal/photodynamic tumor treatment.

"Click" chemistry-based surface modification of poly(dimethylsiloxane) for protein separation in a microfluidic chip.

"Click" chemistry-based surface modification strategy was developed for PDMS microchips to enhance separation performance for both amino acids and proteins. Alkyne-PEG was synthesized by a conventional procedure and then "click" grafted to azido-PDMS. FTIR absorption by attenuated total reflection and contact angle measurements proved efficient grafting of alkyne-PEG onto PDMS surface. Manifest EOF regulation and stability of PEG-functionalized PDMS microchips were illustrated via EOF measurements and protein adsorption investigations. The stability of nonspecific protein adsorption resistance property was investigated up to 30 days. Separation of fluorescence-labeled amino acids and proteins was further demonstrated with high repeatability and reproducibility. Comparison of protein separation using PDMS microchips before and after surface modification suggested greatly improved electrophoretic performance of the PEG-functionalized PDMS microchips. We expect the "click" chemistry-based surface modification method to have wide applications in microseparation of proteins with long-term surface stability.

Environmentally friendly surface modification of PDMS using PEG polymer brush.

A PEG-NH2-based environmentally friendly surface modification strategy was developed for PDMS microchips to prevent protein adsorption and to enhance separation performance. PEG-NH2 was synthesized using a modified synthesis procedure. A two-step grafting method was used for PDMS modification. FTIR absorption by attenuated total reflection and contact angle measurements verified the successful grafting of PEG-NH2 onto the PDMS surface. Subsequent EOF Measurements and protein adsorption studies of PEG-modified PDMS microchips revealed noticeable EOF suppression and resistance to nonspecific protein adsorption for more than 30 days. Separation of four FITC-labeled amino acids was further demonstrated with high repeatability and reproducibility. Comparison of electrophoresis of 3-(2-furoyl)quinoline-2-carboxaldehyde-labeled BSA using PDMS microchips before and after surface modification resulted in significantly improved electrophoretic performance of the PEG-modified PDMS microchips, suggesting that our PEG grafting method successfully modified PDMS surface property and prevented adsorption of proteins. We expect that this environmentally friendly surface modification method will be useful for future protein separations with long-term surface stability.

Competitive Immunoassays Using Antigen Microarrays.

In this work, a non-fouling antigen competitive immunoassay microarray based on the polymer brush is reported to detect multiple mycotoxins. The detection is achieved by utilizing highly specific monoclonal antibodies produced in our laboratory. The polymer brush, poly[oligo(ethylene glycol) methacrylate-co-glycidyl methacrylate] (POEGMA-co-GMA), is synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP) on standard glass slides. In the polymer brush, the epoxy groups of glycidyl methacrylate (GMA) residues provide covalent binding sites for spotted antigens. Moreover, the abundant poly(ethylene glycol) (PEG) side chains in the brush are able to ultimately suppress the nonspecific protein adsorption in solution (non-fouling). The polymer brush shows a high and uniform protein loading, along with a high resistance to nonspecific protein absorption that are both important to achieve a highly sensitive immunoassay. As a demonstration of a multiplex assay, aflatoxin B1 (AFB1), ochratoxin A (OTA), and zearalenone (ZEN) are selected as antigen targets for simultaneous detections using the microarray.

Sensitive competitive immunoassay of multiple mycotoxins with non-fouling antigen microarray.

Various mycotoxins with strong carcinogenesis and toxicity are fatal threats in food safety, and require highly sensitive and high-throughput detections greatly. Herein a fluorescent competitive immunoassay microarray based on a non-fouling polymer brush, poly[(ethylene glycol) methacrylate-co-glycidyl methacrylate] (POEGMA-co-GMA) is explored to sensitively detect multiple mycotoxins with aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEN) as template targets. Due to uniformly large protein loading and high resistance to nonspecific protein absorption of the POEGMA-co-GMA brush, the optimal microarray exhibits wide dynamic ranges of three orders of magnitudes and low detection limits of 4, 4 and 3 pg mL(-1), respectively, which is much better than that obtained with an epoxy-functionalized antigen microarray, and is comparable or even better than the conventional ELISA method. This work offers a powerful high-throughput tool to fast screening of toxins in food quality and environmental monitoring.