Notes

Q-switched 1329  nm Nd:CNGG laser.
Antibiotics abuse now poses a global threat to public health. Monitoring their residual levels as well as metabolites are of great importance, still challenges remain in in situ tracing during the circulation. Herein, taking the typical antibacterial Enrofloxacin (ENR) as a subject, a paper-based aptasensor was tailored by manipulating a duo of aptameric moieties to "sandwich" the target in a lateral-flow regime. To visualize the tight-binding sandwich motif more vividly, an irregular yet robust DNA-bridged gold nanoparticles (AuNPs) proximity strategy was developed with recourse to terminal deoxynucleotidyl transferase, of which the nonaggregate constraining feature was unveiled via optical absorption and scanning probe topography. This complex performed exceptionally better in the test strip context than single-particle tags, leading to an enhanced on-chip focusing. Rather than qualitative color developing, further efforts were taken to visualize the readouts in a quantitative manner by exploiting the smartphone camera for pattern recognition along with data processing in a professional App. Overall, this prototyped contraption realized a rapid and ultrasensitive quantification of ENR down to 0.1 μg/L along with a broad linear range over 5 orders of magnitude, plus excellent selectivity and precision even for real samples. Such innovative fusion across DNA-structured nanomanufacturing and intelligent perception provides a prospective and invigorating solution to point-of-care inspection. In this work, we explored a high efficient electrochemiluminescence (ECL) sensor based on the synergistic enhancement strategy of Zn-doped MoS2 quantum dots (QDs) and reductive Cu(I) particles. On the one hand, Zn-doped MoS2 QDs with sulfur vacancies were designed to improve the ECL activity of QDs. The regulated sulfur vacancies with zinc doping resulted in adsorption and coordination with transition metals of H2O2 as coreactant. On the other hand, reductive Cu(I) particles were prepared to further catalyze the coreactant in the ECL system. The tight combination of glutathione (GSH) and copper in reductive Cu(I) particles can perfectly stabilize Cu(I) with outstanding catalytic activity in neutral pH condition. Under reduction of the cathode, the reductive Cu(I) particles acted as the catalytic role continuously. As a result, more ·OH were generated from H2O2. The signal of Zn-doped MoS2 QDs had 4.5-fold enhancement with the assistance of reductive Cu(I) particles. Furthermore, the DNA walker cycle was designed in presence of T7 exonuclease for HPV 16 DNA detection. The biosensor realized sensitive determination of HPV 16 DNA from 0.1 nmol L-1 to 200 nmol L-1 with the LOD of 0.03 nmol L-1. Interestingly, the entire sensing system can be reproduced on a simple family-friendly device powered by batteries. The ECL signal captured by a smartphone can be processed into high-resolution imaging by self-developed software, which provides great possibility of point-of-care HPV 16 DNA determination in the future. Fabricating a state-of-the-art system capable of probing any chosen target molecule with a high degree of selectivity is the foremost objective of molecular recognition materials. In this paper, we developed a versatile target-probe utilizing zwitterion embedded molecularly imprinted mesoporous organosilica to fill the gap in our current capabilities. Graphene quantum dots were encapsulated as a signal transducer to prepare the fluorescent probe (NTIMO-zQ), and the concentration-dependent emission change was analyzed by adding 3-nitro-L-tyrosine (NT). The NTIMO-zQ showed an unprecedented degree of fluorescence quenching which also exhibited a sub-nanomolar sensitivity for NT; proving itself to be the most sensitive NT probe reported to date. By investigating the sigmoidal fitting of this quenching behavior, the selectivity performance can be quantitatively analyzed; and the resulting measurements are taken to determine the effective concentration (EC50) values with respect to NT. The NTIMO-zQ probe presents an extremely low EC50 with NT (9.7 nM) compared to several other NT analogues. The probe we have developed is both reproducible and repeatable with a satisfactory recovery rate (97-102%), and moreover, it exhibits suitably low detection limit (0.0129 nM). The patterned LIG flakes are generally not interconnected due to the line gap of the laser ray, leading to lower uniform conductivity and fragile graphene. Thus, the fabrication of a highly conductive and mechanically robust LIG-based biosensing platform remains challenging. In this study, the fabrication of a flexible electrochemical biosensor is reported based on poly (3, 4-ethylene dioxythiophene)-poly (styrene sulfonate) (PEDOTPSS) modified 3-dimensional (3D) stable porous laser-induced graphene (LIG) for the detection of glucose and pH. PEDOTPSS was spray-coated on the LIG to improve electrode robustness and deliver uniform electrical conductivity. The as-prepared PEDOTPSS modified LIG (PP/LIG) was characterized using field-emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Platinum and palladium nanoparticles (Pt@Pd) were successfully electrodeposited on PP/LIG, markedly enhancing the electrocatalytic activity for glucose detection. The fabricated biosensor exhibited an excellent amperometric response to glucose with a wide linear range of 10 μM - 9.2 mM, a high sensitivity of 247.3 μAmM-1cm-2, and a low detection limit (LOD) of 3 μM, with high selectivity. In addition, the pH sensor was functionalized by the polyaniline (PANI) on PP/LIG, and it also exhibited excellent potentiometric response with a high sensitivity of 75.06 mV/pH in the linear range of pH 4 - 7. Ultimately, the feasibility of the biosensor was confirmed by the analysis of human perspiration collected during physical exercise. This approach validates the utility of the novel fabrication procedure, and the potential of the LIG-conductive polymer composite for biosensing applications. Exosomes are nanoscale phospholipid bilayer membrane-enclosed vesicles released from cells with diameters of 30-150 nm. Their contents reflect significant information regarding the cancer microenvironment from their parent cells, which attracts increasing attention as potential biomarkers for noninvasive early diagnosis. Among their detection methods, aptasensor has been becoming an attractive star with its properties of affordability, easy to use, fast response, high sensitivity, remarkable specificity, and multiplexing capability. This review mainly summarizes the recent advances of single-stranded DNA (ssDNA) aptamer-based sensors for cancer and tumor-derived exosomes detection. Firstly, we present a brief overview of aptamers and exosomes. https://www.selleckchem.com/PARP.html Then, we introduce the exosomal proteins used as potential biomarkers of various cancers, and their specific ssDNA aptamers used in aptasensors. We emphasize eight major types of aptasensors fluorescent, electrochemical, colorimetric, luminescence, lateral flow strips, surface-enhanced Raman scattering, surface plasmon resonance, and giant magnetoresistance sensors, based on fabrication methods, bio-recognition mechanism, as well as detection evaluation. The future directions and challenges are finally proposed for aptamers and their more applications in exosomes research. Enzyme-based assays have been extensively used for the early diagnosis of disease-related biomarkers. However, these assays are time-consuming, resource-intensive, and infrastructure-dependent, which renders them unsuitable and impractical for use in resource-constrained areas. Thus, there is a strong demand for a biocompatible and potentially generalizable sensor that can rapidly detect cancer biomarkers at ultralow concentration. Herein, an enzyme-free, cost-efficient, and easy-to-use assay based on a novel approach that entails fluorescent molecularly imprinting conjugated polythiophenes (FMICPs) for cancer biomarkers detection is developed. The promising conjugated polythiophenes structure, with a PLQY as high as 55%, provides a straightforward, and affordable method for free-enzyme signal generation. More importantly, the feasibility of integrating printed-paper technology with a sensitive and cost-effective smartphone and portable prototype testing device that could be utilized for rapid point-of-care (POC) cancer diagnostics is successfully introduced. Significantly, the unique structure of FMICP nanofibers (FMICP NFs) displays superior performance with enhanced sensitivity that is 80 times higher than that of pristine FMICP. This assay could lower the limits of detection to 15 fg mL-1 and 3.5 fg mL-1 for α-fetoprotein (AFP) and carcinoembryonic antigen (CEA), respectively, which are three orders of magnitude exceeding that of the standard enzyme-based assay. Moreover, the developed sensors are successfully applied to the fast diagnosis of AFP in liver cancer patients and the FMICP and FMICP NFs results are in excellent agreement with those of clinical ELISA. The progesterone (P4) level in body fluids can act as an indicator for early pregnancy diagnosis and offers insight into mammalian somatic function. In this work, we designed an antibody-aptamer based sandwich assay as a cathodic photoelectrochemical (PEC) biosensor for P4 detection. The composites of carbon dots and graphene oxide (CDs-GO) with favorable cathodic photocurrent response were used as photoactive materials on which the antibody (Ab) of P4 was immobilized. Meanwhile, high affinity truncated P4 aptamer was immobilized on Au-CuO-Cu2O to act as a bioconjugate. When P4 was present, the aptamer-Au-CuO-Cu2O bioconjugate could amplify the cathodic photocurrent of CDs-GO modified electrode through Ab-P4-aptamer interactions. Under optimum conditions, the cathodic photocurrent of the constructed PEC biosensor was found to increase linearly with P4 in a wide concentration range from 0.5 nM to 180 nM, with a low detection limit (3S/N) of 0.17 nΜ. The proposed cathodic PEC sensing platform demonstrated high selectivity, satisfying reproducibility, good stability. The sensor was successfully applied in the determination of P4 in human serum samples. While the monitoring of pH has demonstrated to be an effective technique to monitor an individual's health state, the design of wearable biosensors is subject to critical challenges, such as high fabrication costs, thermal drift, sensitivity to moisture, and the limited applicability for users with metal allergies. This work describes the low-cost fabrication of waterproof electronic decals (WPEDs) highly conformable disposable biosensors capable of monitoring sweat and vaginal pH. WPEDs contain a polyaniline/silver microflakes sensing layer optimized for accurate impedance-based pH quantification across the clinically relevant range of variation of most biofluids. WPEDs also contain a heating layer that serves to both stimulate sweating and prevent saturation of the sensing area, reducing the variability of the measurements. The conformability of WPEDs enables their simple and allergy-free attachment to skin, where they can monitor sweat pH, or to the surface of paper-based sample containers, for the pH-based diagnosis of bacterial vaginosis.
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