Wearable, Biocompatible, and Dual-Emission Ocular Multisensor Patch for Continuous Profiling of Fluoroquinolone Antibiotics in Tears.

The abuse or misuse of antibiotics in clinical and agricultural settings severely endangers human health and ecosystems, which has raised profound concerns for public health worldwide. Trace detection and reliable discrimination of commonly used fluoroquinolone (FQ) antibiotics and their analogues have consequently become urgent to guide the rational use of antibiotic medicines and deliver efficient treatments for associated diseases. Herein, we report a wearable eye patch integrated with a quadruplex nanosensor chip for noninvasive detection and discrimination of primary FQ antibiotics in tears during routine eyedrop treatment. A set of dual-mode fluorescent nanoprobes of red- or green-emitting CdTe quantum dots integrated with lanthanide ions and a sensitizer, adenosine monophosphate, were constructed to provide an enhanced fluorescence up to 45-fold and nanomolar sensitivity toward major FQs owing to the aggregation-regulated antenna effect. The aggregation-driven, CdTe-Ln(III)-based microfluidic sensor chip is highly specific to FQ antibiotics against other non-FQ counterparts or biomolecular interfering species and is able to accurately discriminate nine types of FQ or non-FQ eyedrop suspensions using linear discriminant analysis. The prototyped wearable sensing detector has proven to be biocompatible and nontoxic to human tissues, which integrates the entire optical imaging modules into a miniaturized, smartphone-based platform for field use and reduces the overall assay time to ∼5 min. The practicability of the wearable eye patch was demonstrated through accurate quantification of antibiotics in a bactericidal event and the continuous profiling of FQ residues in tears after using a typical prescription antibiotic eyedrop. This technology provides a useful supplement to the toolbox for on-site and real-time examination and regulation of inappropriate daily drug use that might potentially lead to long-term antibiotic abuse and has great implications in advancing personal healthcare techniques for the regulation of daily medication therapy.

In situ construction of covalent-organic framework on hydrogen-bond organic framework: Fluorescence detection and removal of 4-nitrophenol and metamitron in aqueous media.

A multifunctional COF@HOF (ETTA-DFP@TCBP-HOF) composite is prepared by adding red-fluorescent ETTA-DFP COF to the blue-fluorescent TCBP-HOF preparation system through molecular hydrogen bonding or π - π stacking interactions in situ one-pot synthesis. ETTA-DFP@TCBP-HOF is a multifunctional material for the quantitative detection and simultaneous adsorption of 4-nitrophenol (4-NP) and metamitron (MET) in aqueous solution. As a dual-emission fluorescent sensor, the ETTA-DFP@TCBP-HOF has both fluorescence of TCBP-HOF at 474 nm and ETTA-DFP COF at 592 nm, which shows a ratiometric response to 4-NP and MET with high selectivity, good sensitivity, good anti-interference performance and fast response. As a adsorbent, ETTA-DFP@TCBP-HOF displays rapid adsorption kinetics, and acceptable adsorption capacity for 4-NP and MET. In conclusion, this work constructs a novel multifunctional hybrid material with dual-emission center of HOF and COF, which can not only be used as a ratiometric fluorescent probe for detection, but also for removal of hazardous pollutants, suggesting a new strategy for environmental remediation and human health.

Dual modes of fluorescence sensing and smartphone readout for sensitive and visual detection of mercury ions in Porphyra.

A convenient and intuitive method for detecting trace heavy metal ions is vital for food safety and quality monitoring. Herein, a dual-emission ratiometric fluorescence probe based on Zr-based metal-organic frameworks (Zr-MOF) and silver nanoclusters (AgNCs) was assembled to sensitive and visual detect mercury ions (Hg2+). The sensor exhibits good sensitivity from 0.010 to 0.5 µg mL-1 with a low detection limit of 1.8 µg L-1 (corresponding to 0.72 µg kg-1 by weight). The proposed method was finally applied to determine Hg2+ in the Porphyra matrix with satisfactory outcomes, the analytical recoveries were in the range of 94.74%-101.1%, indicating the practicability of the developed method. Meanwhile, the smartphone-based colorimetric method was established by capturing the changes in fluorescence colors of the probes exposed to different Hg2+ concentrations, with a quick sample-to-answer monitoring time of 10 min. The fluorescence probe, with these merits of simplicity, rapid response, and high sensitivity, offered a promising means for evaluating the safety of food polluted with Hg2+.

Random forest algorithm-enhanced dual-emission molecularly imprinted fluorescence sensing method for rapid detection of pretilachlor in fish and water samples.

A sensitive and efficient fluorescence sensor based on dual-emission molecularly imprinted polymers (Dual-em-MIPs) was successfully developed using the random forest (RF) machine-learning algorithm for the rapid detection of pretilachlor. SiO2 coatings on red-emitting CdSe/ZnS quantum dots (r-SiO2@QDs) as intermediate light-emitting components are non-selective for pretilachlor, whereas molecularly imprinted layers coated with blue-emitting nitrogen-doped graphene quantum dots (N-GQDS) are selective. Fluorescence images of the Dual-em-MIPs were acquired. The red (R), green (G), and blue (B) color values of the image were analyzed using an RF algorithm, and the classifier was trained using 103 fluorescent images for automatic analyses. Under optimized conditions, an excellent linear relationship between the sensor and pretilachlor was obtained in the range of 0.001-5.0 mg/L (R2, 0.9958). Additionally, the satisfactory recoveries of Dual-em-MIPs ranged between 92.2 % and 107.6 % for the real samples, with a relative standard deviation (RSD) under 6.5 %. The satisfactory recoveries of the RF model based on the fluorescence sensor were 84.2-108.2 % with the RSD under 6.4 %. Overall, the proposed fluorescence sensor based on Dual-em-MIPs and machine learning methods was successfully used to determine pretilachlor in the environment and in aquatic products.

Dual-Emission Fluorescence Probe Based on CdTe Quantum Dots and Rhodamine B for Visual Detection of Mercury and Its Logic Gate Behavior.

It is urgent that a convenient and sensitive technique of detecting Hg2+ be developed because of its toxicity. Conventional fluorescence analysis works with a single fluorescence probe, and it often suffers from signal fluctuations which are influenced by external factors. In this research, a novel dual-emission probe assembled through utilizing CdTe quantum dots (QDs) and rhodamine B was designed to detect Hg2+ visually. Only the emission of CdTe QDs was quenched after adding Hg2+ in the dual-emission probe, which caused an intensity ratio change of the two different emission wavelengths and hence facilitated the visual detection of Hg2+. Compared to single emission QDs-based probe, a better linear relationship was shown between the variation of fluorescence intensity and the concentration of Hg2+, and the limit of detection (LOD) was found to be11.4 nM in the range of 0-2.6 µM. Interestingly, the intensity of the probe containing Hg2+ could be recovered in presence of glutathione (GSH) due to the stronger binding affinity of Hg2+ towards GSH than that towards CdTe QDs. Based on this phenomenon, an IMPLICATION logic gate using Hg2+/GSH as inputs and the fluorescence signal of QDs as an output was constructed.

Fluorometric sensing of oxygen using manganese(II)-doped zinc sulfide nanocrystals.

Manganese(II)-doped zinc sulfide nanocrystals (Mn:ZnS NCs) with dual-emission fluorescence (peaks at 445 nm and 590 nm under 330 nm excitation), good water stability and low toxicity were synthesized by hot injection. The fluorescence intensity of both emission bands of the nanocrystals can change rapidly by the content of gaseous and dissolved oxygen. The process is fully reversible. Compared with the maximum intensity of Mn:ZnS sensing film in 100% nitrogen, the emission of the blue emission decreases by 72% in the presence of 100% oxygen, and the yellow emission by 32%. Response is linear in the presence of 3% to 12% of oxygen percentage in gas. For water-dissolved oxygen, the linear response occurs between 0.54 and 11.4 mg·L-1. Graphical abstractMn-doped ZnS NCs with dual-emission fluorescence were synthesized by hot-injection method. The reversible and rapid sensing characteristics of Mn-doped ZnS NCs to oxygen were studied, and the possible sensing mechanism was investigated.

Molecularly Imprinted Fluorescent Test Strip for Direct, Rapid, and Visual Dopamine Detection in Tiny Amount of Biofluid.

Paper-based assays for detection of physiologically important species are needed in medical theranostics owning to their superiorities in point of care testing, daily monitoring, and even visual readout by using chromogenic materials. In this work, a facile test strip is developed for visual detection of a neurotransmitter dopamine (DA) based on dual-emission fluorescent molecularly imprinted polymer nanoparticles (DE-MIPs). The DE-MIPs, featured with tailor-made DA affinity and good anti-interference, exhibit DA concentration-dependent fluorescent colors, due to the variable ratios of dual-emission fluorescence caused by DA binding and quenching. By facile coating DE-MIPs on a filter paper, the DA test strips are obtained. The resultant test strip, like the simplicity of a pH test paper, shows the potential for directly visual detection of DA levels just by dripping a tiny amount of biofluid sample on it. The test result of real serum samples demonstrates that the DA strip enables to visually and semiquantitatively detect DA within 3 min by using only 10 µL of serum samples and with a low detection limit ((100-150) × 10-9 m) by naked eye. This work thus offers a facile and efficient strategy for rapid, visual, and on-site detection of biofluids in clinic.