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Lactate is a critical regulatory factor secreted by tumors, influencing tumor development, metastasis, and clinical prognosis. Precise analysis of tumor-cell-secreted lactate is pivotal for early cancer diagnosis. This study describes a paper-based microfluidic chip to enable the detection of lactate levels secreted externally by living cells. Under optimized conditions, the lactate biosensor can complete the assay in less than 30 min. In addition, the platform can be used to distinguish lactate secretion levels in different cell lines and can be applied to the screening of antitumor drugs. Through enzymatic chemical conversion, this platform generates fluorescent signals, enabling qualitative assessment under a handheld UV lamp and quantitative analysis via grayscale intensity measurements using ImageJ (Ver. 1.50i) software. The paper-based platform presented in this study is rapid and highly sensitive and does not necessitate other costly and intricate instruments, thus making it applicable in resource-constrained areas and serving as a valuable tool for investigating cell lactate secretion and screening various anti-cancer drugs. [ABSTRACT FROM AUTHOR]

The germination of bacterial spores presents a considerable challenge to health and safety due to the current scarcity of cost-effective and efficient tools for their prompt identification. Addressing this critical need, our study introduces a novel paper-based ratiometric fluorescence sensor platform utilizing a composite of Eu3+-doped carbon quantum dots (CQDs) within ZIF-8 (Eu3+-CQDs@ZIF-8). This platform facilitates the rapid detection of 2, 6-pyridinedicarboxylic acid (DPA), a biomarker of bacterial spore germination. To fabricate this sensor, CQDs and Eu3+ ions were synergistically integrated into the ZIF-8 framework. The resultant composite was then applied to filter paper via screen printing technology, creating a paper-based microfluidic analytical device (μPAD). During the process of detecting DPA, strong coordination between DPA and Eu3+ ions is established, resulting in an enhanced red emission due to energy transfer through the antenna effect. Concurrently, the interaction between DPA and CQDs leads to a quenching of the CQDs' green fluorescence, enabling a ratiometric detection of DPA. The efficacy of this composite material was validated through the visualization of DPA release during spore germination. Further enhancing the platform's utility, integration with a smartphone enabled the quantification of DPA concentrations in real samples by analyzing the red-to-green (R/G) value in the detection area. Demonstrating rapid, sensitive, and precise DPA detection, the platform confirms its suitability for practical applications. Conclusively, with its compact design, straightforward preparation, and comprehensive integration, this sensor platform emerges as a promising solution for on-site spore detection, highlighting its potential for widespread testing applications. [ABSTRACT FROM AUTHOR]

Lactate is a critical regulatory factor secreted by tumors, influencing tumor development, metastasis, and clinical prognosis. Precise analysis of tumor-cell-secreted lactate is pivotal for early cancer diagnosis. This study describes a paper-based microfluidic chip to enable the detection of lactate levels secreted externally by living cells. Under optimized conditions, the lactate biosensor can complete the assay in less than 30 min. In addition, the platform can be used to distinguish lactate secretion levels in different cell lines and can be applied to the screening of antitumor drugs. Through enzymatic chemical conversion, this platform generates fluorescent signals, enabling qualitative assessment under a handheld UV lamp and quantitative analysis via grayscale intensity measurements using ImageJ (Ver. 1.50i) software. The paper-based platform presented in this study is rapid and highly sensitive and does not necessitate other costly and intricate instruments, thus making it applicable in resource-constrained areas and serving as a valuable tool for investigating cell lactate secretion and screening various anti-cancer drugs.

Cardiovascular disease is a major global public health challenge. Point-of-- care testing (POCT) technologies are crucial for the prevention, early diagnosis, and treatment of cardiovascular conditions. Numerous POCT technologies for cardiovascular disease are currently available, which include but are not limited to conventional methods, paper-based microfluidic technology, microfluidic chip technology, electrochemical detection technology, ultrasonic detection technology, and smartphone-based detection technology. Each method has a broad range of applications and performs differently across various detection scenarios. This article offers a comprehensive analysis of current POCT technologies for cardiovascular disease, assessing their effectiveness, limitations, and future development directions. The aim is to provide insights and theoretical references for innovative research and clinical applications in POCT methods for cardiovascular disease., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The presence of fluoroquinolone (FQs) antibiotic residues in the food and environment has become a significant concern for human health and ecosystems. In this study, the background-free properties of upconversion nanoparticles (UCNPs), the high specificity of the target aptamer (Apt), and the high quenching properties of graphene oxide (GO) were integrated into a microfluidic-based fluorescence biosensing chip (MFBC). Interestingly, the microfluidic channels of the MFBC were prepared by laser-printing technology without the need for complex preparation processes and additional specialized equipment. The target-responsive fluorescence biosensing probes loaded on the MFBC were prepared by self-assembly of the UCNPs-Apt complex with GO based on π-π stacking interactions, which can be used for the detection of the two FQs on a large scale without the need for multi-step manipulations and reactions, resulting in excellent multiplexed, automated and simultaneous sensing capabilities with detection limits as low as 1.84 ng/mL (enrofloxacin) and 2.22 ng/mL (ciprofloxacin). In addition, the MFBC was integrated with a smartphone into a portable device to enable the analysis of a wide range of FQs in the field. This research provides a simple-to-prepare biosensing chip with great potential for field applications and large-scale screening of FQs residues in the food and environment. [Display omitted] [ABSTRACT FROM AUTHOR]