Contractile Hairpin DNA-Mediated Dual-Mode Strategy for Simultaneous Quantification of Lactoferrin and Iron Ion by Surface-Enhanced Raman Scattering and Fluorescence Analysis

Three-Dimensional DNA Hydrogel Mediated Dual-Mode Sensing Method for Quantification of Epithelial Cell Adhesion Molecule in Biological Fluid Samples

Monitoring changes in the expression of marker proteins in biological fluids is essential for biomarker-based disease diagnosis. Epithelial cell adhesion molecule (EpCAM) has been identified as a broad-spectrum biomarker for various chronic diseases and as a therapeutic target. However, the development of simple and reliable methods for quantifying EpCAM changes in biological fluids faces challenges due to the variability of its expression across different diseases, the presence of soluble forms, and matrix effects. In this paper, a surface-enhanced Raman scattering (SERS)-fluorescence (FL) dual-mode sensing method was established for quantification of trace EpCAM in biological fluids based on bimetallic Au@Ag nanoparticles and nitrogen-doped quantum dots encapsulated DNA hydrogel hybrid with graphene oxide (Au@Ag-NQDs/GO). The DNA hydrogel was constructed based on three-dimensional (3D) structure DNA-mediated strategy using an aptamer DNA (AptDNA) linker. The interaction of the AptDNA with EpCAM triggered the disassembly of the DNA hydrogel. Consequently, the release of Au@Ag nanoparticles induced an "on-off" switch in the SERS signal while the weakened FL quenching effect in Au@Ag-NQDs/GO system achieved "off-on" switch of FL signal, enabling the simultaneous SERS-FL quantification of EpCAM. The established dual-mode method exhibited outstanding sensitivity and stability in quantifying EpCAM in the range of 0.5-60.0 pg/mL, with the limits of detection (LODs) of SERS and FL as 0.17 and 0.35 pg/mL, respectively. When applied for real sample analysis, the method showed satisfactory specificity and recoveries in cancer cells lysate, serum, and urine samples with RSDs of 2.8-6.3%, 4.0-6.3%, and 2.8-5.7%, respectively. The developed SERS-FL sensing method offered a sensitive, reliable, and practical quantification strategy for trace EpCAM in diverse biological fluid samples, which would benefit the early diagnosis of disease and further health management.

Multifunctional Metal-Organic Frameworks Driven Three-Dimensional Folded Paper-Based Microfluidic Analysis Device for Chlorpyrifos Detection

Chlorpyrifos (CPF) residues in food pose a serious threat to ecosystems and human health. Herein, we propose a three-dimensional folded paper-based microfluidic analysis device (3D-μPAD) based on multifunctional metal-organic frameworks, which can achieve rapid quantitative detection of CPF by fluorescence-colorimetric dual-mode readout. Upconversion nanomaterials were first coupled with a bimetal organic framework possessing peroxidase activity to create a fluorescence-quenched nanoprobe. After that, the 3D-μPAD was finished by loading the nanoprobe onto the paper-based detection zone and spraying it with a color-developing solution. With CPF present, the fluorescence intensity of the detection zone gradually recovers, the color changes from colorless to blue. This showed a good linear relationship with the concentration of CPF, and the limits of detection were 0.028 (fluorescence) and 0.043 (colorimetric) ng/mL, respectively. Moreover, the 3D-μPAD was well applied in detecting real samples with no significant difference compared with the high-performance liquid chromatography method. We believe it has huge potential for application in the on-site detection of food hazardous substance residues.

Thermodynamic Allosteric Switch-Actuated 3D DNA Nanomachine for Ultrasensitive Electrochemical/Fluorescent Dual-Mode Biosensing of a Transcription Factor

Herein, we reported an innovative thermodynamic allosteric switch-actuated 3D DNA nanomachine for selective, sensitive, and accurate electrochemical (EC)/fluorescent (FL) dual-mode biosensing of a microphthalmia-associated transcription factor (MITF). The thermodynamic allosteric switch was ingeniously customized as a hairpin probe (HP) that was in dynamic equilibrium but rapidly interconverting conformations. At the "inactive state", the MITF-binding region and the switch part were "sequestered". Upon the introduction of MITF, an MITF-HP complex promptly formed, and the equilibrium of HP thermodynamically inclined from the "inactive state" toward the "active state" conformation. Immediately, the exposed switch on HP effectively actuated the 3D DNA nanomachine and synchronously produced the restriction site for Nb.BbvCI nicking endonuclease. After the autonomous conveying of the 3D DNA nanomachine by means of the high-efficiency circularly nicking endonuclease signal amplification (NESA), not only was MB-S1 in the supernatant used for FL measurements but also MB-SP/MNs/S2 in the precipitate was adapted for EC analysis, significantly improving the utilization of output products derived from the 3D DNA nanomachine. Accordingly, benefiting from the efficient DNA nanomachine signal amplification manner and the self-calibration function of a dual-mode bioassay, the constructed biosensor exhibits superior sensitivity and accuracy for MITF determination.

Spectroscopic imaging to assess biochemical alterations in liver carcinoma cells exposed to transition metals

Despite the invaluable role of transition metals in every living organism, it should be remembered that failure to maintain the proper balance and exceed the appropriate dose may have the opposite effect. In the era of such a popular and propagated need for supplementation in the media, one should bear in mind the harmful effects that may become the result of improper and excessive intake of transition metals. This article establishes the feasibility of Raman (RS) and Fourier-transform infrared (FT-IR) spectroscopic imaging at the single-cell level to investigate the cellular response to various transition metals. These two non-destructive and perfectly complementary methods allow for in-depth monitoring of changes taking place within the cell under the influence of the agent used. HepG2 liver carcinoma cells were exposed to chromium, iron, cobalt, molybdenum, and nickel at 1 and 2 mM concentrations. Spectroscopic results were further supported by biological evaluation of selected caspases concentration. The caspase- 3, 6, 8, 9, and 12 concentrations were determined with the use of the enzyme-linked immunosorbent assay (ELISA) method. This study shows the induction of apoptosis in the intrinsic pathway by all studied transition metals. Cellular metabolism alterations are induced by mitochondrial metabolism changes and endoplasmic reticulum (ER) metabolism variations. Moreover, nickel induces not only the intrinsic pathway of apoptosis but also the extrinsic pathway of this process.

A laser free self-luminous nanosystem for photodynamic therapy of cervical cancer cells

Photodynamic therapy is a tumor treatment strategy. However, most of the photodynamic therapies rely on laser irradiation triggering, which limits their application in deep tissues. This study designed a self-luminescent nano system, hybrid protein oxygen nanocarrier coated graphene quantum dots (GQDs@HPOC) and mesoporous silica nanoparticles coated Luminol (L@MSNs), which self-assembled into GQDs@HPOC/L@MSNs without laser irradiation. The system utilized the weak acidic environment of tumors to trigger the release of Luminol and the chemiluminescence was catalyzed by HPOC. Next CRET occurred between Luminol and GQDs, producing 1O2, which could generate photodynamic damage to cervical cancer cells without the need for external laser irradiation. The system achieved the peak uptake in primary cervical cancer cells in 3 h, and had good biosafety before self-assembly. The system could significantly kill cells at a concentration of 16 μg/ml. The system will be further applied in in vivo experiments to investigate its therapeutic ability, providing a new strategy for the clinical treatment of cervical cancer.

Complementary Homogeneous Electrochemical and Photothermal Dual-Modal Sensor for Highly Sensitive Detection of Organophosphorus Pesticides via Stimuli-Responsive COF/Methylene Blue@MnO2 Composite

Credible and on-site detection of organophosphorus pesticides (OPs) in complex matrixes is significant for food security and environmental monitoring. Herein, a novel COF/methylene blue@MnO2 (COF/MB@MnO2) composite featured abundant signal loading, a specific recognition unit, and robust oxidase-like activity was successfully prepared through facile assembly processes. The multifunctional composite acted as a homogeneous electrochemical and photothermal dual-mode sensing platform for OPs detection through stimuli-responsive regulation. Without the presence of OPs, the surface MnO2 coating could recognize thiocholine (TCh), originating from acetylcholinesterase (AChE)-catalyzed hydrolysis of acetylthiocholine (ATCh), and exhibited a distinctly amplified diffusion current due to the release of plentiful MB; while the residual MnO2 nanosheets could only catalyze less TMB into oxidized TMB (oxTMB) with a typical near-infrared (NIR) absorption, enabling NIR-driven photothermal assay with a low temperature using a portable thermometer. Based on the inhibitory effect of OPs on AChE activity and OP-regulated generation of TCh, chlorpyrifos as a model target can be accurately detected with a low limit of detection of 0.0632 and 0.108 ng/mL by complementary electrochemical and photothermal measurements, respectively. The present dual-mode sensor was demonstrated to be excellent for application to the reliable detection of OPs in complex environmental and food samples. This work can not only provide a complementary dual-mode method for convenient and on-site detection of OPs in different scenarios but also expand the application scope of the COF-based multifunctional composite in multimodal sensors.

Regulated synthesis of an Au NB-DT@Ag bimetallic core-molecule-shell nanostructure for reliable SERS detection

In recent research, anisotropic plasmonic core-shell nanomaterials have gained a lot of attention in surface-enhanced Raman scattering (SERS) due to their brilliant uniformity and optical properties. Herein, a bimetallic core-molecule-shell (CMS) composite nanorod SERS substrate nanomaterial (Au NB-DT@Ag NRs) was designed and synthesized under precise regulation. The inner core is gold nanobipyramids (Au NBs), which possess superior plasmonic properties. Uniform Au NBs of five different sizes were fabricated via a penta-twinned gold seed mediated growth method. The length varied from 160 to 62 nm and the corresponding diameter varied from 60 to 23 nm while the longitudinal surface plasmonic resonance (SPR) changed from 908 to 715 nm. The SERS activity of five Au NBs were compared and the optimally sized one with a length of 78 nm and width of 28 nm was set as the inner core. After modification with the Raman reporter (DT), different amounts of silver were deposited on the surface of Au NB-DTs to form an Au NB-DT@Ag nanocomposite. The shape of the nanostructure gradually became a rod and lengthened while the longitudinal SPR wavelength varied from 733 nm to 664 nm with an increase in the amount of silver nitrate added. The Au NB-DT@Ag NRs with the best SERS activity (b-3) could realize the quantitative detection of the toxic dyes malachite green (MG) and crystal violet (CV) of concentrations as low as 5 × 10-9 M, showing good reproducibility and stability. This work offers a new design strategy for a SERS substrate for reliable quantitative SERS detection applications.

Recent Advances in the DNA-Mediated Multi-Mode Analytical Methods for Biological Samples

DNA-mediated nanotechnology has become a research hot spot in recent decades and is widely used in the field of biosensing analysis due to its distinctive properties of precise programmability, easy synthesis and high stability. Multi-mode analytical methods can provide sensitive, accurate and complementary analytical information by merging two or more detection techniques with higher analytical throughput and efficiency. Currently, the development of DNA-mediated multi-mode analytical methods by integrating DNA-mediated nanotechnology with multi-mode analytical methods has been proved to be an effective assay for greatly enhancing the selectivity, sensitivity and accuracy, as well as detection throughput, for complex biological analysis. In this paper, the recent progress in the preparation of typical DNA-mediated multi-mode probes is reviewed from the aspect of deoxyribozyme, aptamer, templated-DNA and G-quadruplex-mediated strategies. Then, the advances in DNA-mediated multi-mode analytical methods for biological samples are summarized in detail. Moreover, the corresponding current applications for biomarker analysis, bioimaging analysis and biological monitoring are introduced. Finally, a proper summary is given and future prospective trends are discussed, hopefully providing useful information to the readers in this research field.

Lactoferrin: Antimicrobial impacts, genomic guardian, therapeutic uses and clinical significance for humans and animals

Lactoferrin (LF) is a protein found in several bodily fluids, such as milk. This protein has a diverse range of functions and is evolutionarily conserved. Lactoferrin is a multifunction protein with distinct biological abilities affecting mammals' immune structures. Reports indicated that the daily uptake of LF from dairy products is unsatisfactory in detecting further health-promoting abilities. Research has shown that it protects against infection, mitigates cellular senescence, and improves nutritional quality. Additionally, LF is being studied as a potential treatment for various diseases and conditions, including gastrointestinal issues and infections. Studies have also demonstrated its effectiveness against various viruses and bacteria. In this article, we'll look closer at the structure of LF and its various biological activities, including its antimicrobial, anti-viral, anti-cancer, anti-osteoporotic, detoxifying, and immunomodulatory properties. More specifically, the protective effect of LF against oxidative DNA damage was also clarified through its ability to abolish DNA damaging issues without interfacing with host genetic material. Fortification with LF protects mitochondria dysfunction syndromes via sustaining redox status and biogenesis and suppressing apoptosis and autophagy singling. Additionally, we'll examine the potential benefits of lactoferrin and provide an overview of recent clinical trials conducted to examine its use in laboratory and living models.