Osteoporosis is a significant health concern. While multiple techniques have been utilized to diagnose this condition, certain limitations still persist. Raman spectroscopy has shown promise in predicting bone strength in animal models, but its application to humans requires further investigation. In this study, we present an in vitro approach for predicting osteoporosis in 10 patients with hip fractures using Raman spectroscopy. Raman spectra were acquired from exposed femoral heads collected during surgery. Employing a leave -one -out cross -validated linear discriminant analysis (LOOCV-LDA), we achieved accurate classification (90 %) between osteoporotic and osteopenia groups. Additionally, a LOOCV partial least squares regression (PLSR) analysis based on the complete Raman spectra demonstrated a significant prediction (r 2 = 0.84, p < 0.05) of bone mineral density as measured by dual X-ray absorptiometry (DXA). To the best of our knowledge, this study represents the first successful demonstration of Raman spectroscopy correlating with osteoporotic status in humans.

Amantadine (AMD) residue can accumulate in organisms through the food chain and cause serious harm to human body. AMD can specifically bind to AMD specific aptamer and cause its conformation to change from a random single strand to a stem -loop structure. To avoid the influence of excess nucleotides on binding of aptamer to AMD, the truncation of the AMD original aptamer J was optimized by retaining an appropriate stem -loop structure, and a new type of truncation aptamers was developed in this work. By comparing the truncated aptamer with the original aptamer, it was found that the truncated aptamer J-7 had better affinity and specificity with AMD. The detection limit of AMD was 0.11 ng/mL by using J-7 as specific recognition element and molybdenum disulfide nanosheet (MoS(2)Ns) as signal amplification element. The developed method base on truncated aptamer J-7 was used for detection of AMD in milk, yogurt and SD rat serum samples for the first time with recoveries of 86.6%108.2%. This study provided a reference for truncating other long sequence aptamers and provided a more sensitive detection method for monitoring AMD residues in food.

Adenosine triphosphate (ATP) has an irreplaceable role in the maintenance of many physiological processes and biological functions, and can be employed as an indicator of many diseases. In this work, we constructed a simple and sensitive dual-signal fluorescence aptasensing system for ATP detection with berberine as the signal reporter, ATP-aptamer as the recognition unit and MoS2 nanosheets as the signal amplification. In the absence of ATP, berberine can bind to the single-stranded DNA (ssDNA) of ATP-aptamer and selectively assemble on the surface of MoS2 nanosheets, leading to the fluorescence quenching of bererbine based on the fluorescence resonance energy transfer, denoted by "OFF". Accordingly, the fluorescence anisotropy signal is enhanced due to restriction on rotate of the fluorescent probe and denoted as "ON". Conversely, in the presence of ATP, it specifically interacts with ATP-aptamer and switches the free-curled single-stranded of ATP-aptamer to the G-quadruplex structure of ATP-aptamer/ATP/berberine, causing the detachment from the surface of the MoS2 nanosheet. Accordingly, the fluorescence signal was reversed from "OFF" to "ON", and the fluorescence anisotropy signal was turned "ON" to "OFF". The developed aptasensing system achieved a desirable sensitivity of 40.0 nM with fluorescent mode, and of 20.8 nM with fluorescent anisotropic mode. The sensing system has demonstrated high quality detection performance in human serum sample, and obtained the satisfactory recovery results for fluorescent of 93.0-108.5%, fluorescent anisotropic of 96.4-106.7%.

DNA-based molecular logic gates have been developed rapidly but most of them have a single output mode. This study is to develop a triple-output label-free fluorescent DNA-based multifunctional molecular logic gate with berberine as a fluorescent signal and a Ag+-aptamer as a recognition matrix. The Ag+-aptamer has been identified to switch from a random coil to an i-motif structure of C-Ag+-C from a Ag+-induced responsive conformational change. As a fluorescent probe, berberine is ultrasensitive to the changes of microenvironments, and the binding to i-motif DNA's more rigid structure causes a significant increase in fluorescence, anisotropy, and lifetime. The addition of cysteine to the berberine/C-Ag+-C system disintegrates the imotif DNA structure because of the strong coordination between Ag+ and cysteine, and then the triple-output signals are almost retrieved. Given this, a highly sensitive triple-output molecular logic gate for the analyses of Ag+ and cysteine is constructed with high specificity. Moreover, this simple and cost-effective molecular logic gate has been applied for the detection of cysteine and Ag+ in various real environmental samples including river water, PM2.5, soil, and food samples with satisfactory recoveries from 89.83 to 106.04%.

Based on the specific interaction of Ag+ and cytosine-cytosine (C-C) base mismatch and using berberine (Ber) as the fluorescent probe and Exonuclease I (Exo I) as the background fluorescence reducing tool, a label-free Exo I-assisted fluorescence aptamer sensing platform was established for the detection of silver ions with high sensitivity and selectivity. Exo I reduced the fluorescence background of the Ber/Ag+-aptamer complex to a level similar to that of Ber itself in the absence of Ag+. After introducing Ag+ into the sensing system, it induces the aptamer rich in base C to form C-Ag+-C i-motif structure which are resistant to degradation mediated by Exo I. The concentration of Ber, Ag+-aptamer, Exo I and the temperature and reaction time for Exo I were all optimized. Under the optimal experimental conditions, the detection limit of Ag+ was 4.4 nM and the linear range was from 0.0059 mu M to 235.48 mu M with a coefficient of determination (R-2) > 0.99. Moreover, the proposed strategy had been successfully applied to the detection of Ag+ in tap water and human serum with a good recovery ranging from 88.4% to 106.9%. (C) 2021 Elsevier B.V. All rights reserved.

A fluorescence aptasensor for the highly specific and sensitive determination of tetrodotoxin was established with tetrodotoxin-aptamer as the recognition unit, berberine as the signal reporter and exonuclease I as the elimination agent for the background. Berberine has a weak fluorescence emission at 540 nm, and it can form the tetrodotoxin-aptamer/berberine complex, resulted in an increased fluorescence. After introducing exonuclease I, it can degrade the single strand oligonucleotides of tetrodotoxin-aptamer into the single nucleotide in the absence of tetrodotoxin, which lead to dramatic fluorescence quenching, and reduce the background signal of sensing system. Once tetrodotoxin is in the presence, tetrodotoxin-aptamer is converted into the stable neck ring conformation, which resists the degradation of exonuclease I and provides a more rigid micro-environment for the excited state of berberine, and then the strong fluorescence is observed. Based on the above properties, an ultrasensitive label-free fluorescence aptasensor for tetrodotoxin is established. The fluorescence aptasensor shows good analytical performance with the linear increase of fluorescence intensity at the tetrodotoxin concentration from 0.030 nM to 6.0 × 103 nM. The detection limit of 11.0 pM is much lower than that of other reported sensor methods.

In this work, a simple and rapid spectrophotometric method, which is based on the fact that Iron(Ⅱ) -gluconic acid complex as a kind of reducing agent deterioration of indigo carmine dyes, was developed to detect gluconic acid in food. Under the optimal experimental condition, a linear range of 3.6 M to 900 M was obtained for gluconic acid with a limit of detection of 1.1 μM. The colorimetric method was rapid and robust with a low cost and can be applied to gluconic acid detection in food samples.

Tetrodotoxin (TTX) specifically can bind to its nucleic add aptamer (TTX-aptamer) and cause the conformation of TD(-aptamer to be switched from the single-strand random coiling form to the compact neck ring structure. Based on the microenvironment difference of the fluorescence reporter, berberine in between the single-stranded coil oligonucleotides and the structure of the neck ring, a simple, rapid and sensitive label-free fluorescence aptamer sensing system for detection of TTX was developed. Various factors affecting the analysis of TTX were optimized, including the concentration of berberine, ion strength, pH, reaction time, the concentration of TTX-aptamer. Under the optimal experimental conditions, the fluorescence intensity of the sensing system and the concentration of TTX showed a good linear relationship in the range of 0.1 nM to 500 nM, with the detection limit of 0.074 nM. The standard recovery test result exhibited that the recoveries of TIX in serum samples were 96.54%-106.40%. The established method has the advantages of high specificity, good sensitivity, quickness and convenience, low cost, and can be used for the detection of TTX in serum samples. (C) 2019 Elsevier B.V. All rights reserved.

An ultrasensitive phosphorescence sensing system was fabricated to selectively detect lysozyme in humoral samples engaging Mn-doped ZnS quantum dots as the room temperature phosphorescence reporter and lysozyme-aptamer as the recognition unit. The phosphorescence emission of Mn-doped ZnS quantum dots was quenched by lysozyme-aptamer on account of the supramolecular interaction between them. When lysozyme was introduced into the system, it was preferred to form lysozyme-aptamer/lysozyme complex and the lysozyme-aptamer was released from the surface of the quantum dots, and the electron transfer is terminated, causing the phosphorescence of Mn-doped ZnS quantum dots recovery. Various factors including pH effect, the reaction time, the ion strength and the concentration of lysozyme-aptamer were optimized. The results showed that the liner range of the detection of lysozyme in our presentedsensing system was 5.50 nM-44.5 nM (R-2 = 0.998) and the detection limit was 0.54 nM. To test the potential practical application of this system, we used the presented sensing system to determine the content of lysozyme in human serum and urine samples and the recoveries were found in the range of 104.5%-111.7% and 101.5%-102.7%, respectively. Therefore, our phosphorescence sensing system constructed a promising system which was simple, rapid, sensitive and selective for lysozyme detection and also exhibited potential application in biomedical field.

A label-free fluorescent aptasensing platform was fabricated and a simple and rapid method to detect Hg2+ ion in aqueous solution was put forward by means of berberine and Hg2+ ion-aptamer are as the fluorescence probe and the recognition element, respectively. Various factors including the concentration of berberine, Hg2+ ion and Hg2+ ion-aptamer, pH effect and the reaction time were investigated in detail. Under the optimal experimental conditions, in the sensing system, the fluorescence intensity changes displayed a calibration response for Hg2+ ion in the range of 0.1 μM to 10.0 μM and the detection limit was of 7.7 nM (S/N = 3). The fabricated label-free fluorescence aptasensor is not only conveniently but also effectively applicable used for analysis of Hg2+ ion in blood serum and tap water samples and the recovery range is of 96.0%-105.7%. In brief, this study offers an easy, economical and stable assay system for detecting Hg2+ ion in rough condition.

采用电沉积法制备了Ti/Ag+Cu电极并将其用于水杨酸的降解.对含有不同n(Ag)∶n(Cu)的Ti/Ag+Cu电极的电化学性能进行了研究,考察了支持电解质Na2SO4的浓度对水杨酸降解率的影响,并对超声波降解、电化学氧化降解和声电协同降解效果进行了比较.结果表明:在室温条件下,支持电解质Na2SO4的浓度为1.441 g·L-1,Ti/Ag+ Cu电极的n(Ag)∶n(Cu) =5∶5时水杨酸的声电协同降解率为99.2％,有很好的协同降解效用.

Objective:To establish an HPLC method for the simultaneous determination of 5 flavonoid components including hydroxysafflor yellow A(HSYA),6-hydroxykaempferol-3,6-di-O-glucoside(6-HK3,6-O-G),6-hydroxykaempferol-3-O-rutinoside-6-O-glucoside(6-HK3-R-6-G),6-hydroxykaempferol-3-O-glucoside(6-HK3-O-G) and safflower yellow B(SYB) in the flowers of Carthamus tinctorius L.Methods: Venusil XBP-C18(4.6 mm× 250 mm,5μm) was used as the stationary phase.The mobile phase was composed of methanol and water(0.2 mol/L NaClO4-0.2‰ HClO4).The flow rate of mobile phase was 0.8 mL/min.The detection wavelength was 375 nm.Results: The standard curve revealed a good linear relationship over a range of 4.8-600μg/mL for HSYA,4.08-510μg/mL for 6-HK3,6-O-G,4.32-540μg/mL for 6-HK3-R-6-G,4.24-530μg/mL for 6-HK3-O-G and 4.72-590μg/mL for SYB,respectively.The detection limits for HSYA,6-HK3,6-O-G,6-HK3-R-6-G,6-HK3-O-G and SYB were 0.6,0.3,0.4,1.3μg/mLand 0.5μg/mL,respectively.The average recovery rates were 97.1%,93.6%,95.6%,99.7% and 102.3%.Conclusion: This established determination method for flavonoids is rapid and sensitive,which has a good reproducibility and stability and can be used for qualitative evaluation of Carthamus tinctorius L.and safflower yellow.