A lateral flow strip based on gold nanoparticles to detect 6-monoacetylmorphine in oral fluid.

We used lateral flow strips based on gold nanoparticles to detect 6-monoacetylmorphine (6-MAM; heroin's unique metabolite) in oral fluid samples. In this competitive lateral chromatographic immunoassay, the 6-MAM was chemically synthesized and conjugated to bovine serum albumin. The results were qualitatively detected via the colour change of the test line. By using a proper sample pad, a suitable nitrocellulose membrane and a customized sponge device adsorbed the oral fluid directly from the mouth; the total test time was 3 min. The sensitivity of the assay was 4.0 ng ml-1 without any cross-reactivity with 10 normal drugs, which are widely subject to abuse, including morphine and codeine. This test could be easily used on site to detect heroin in oral fluid, and it could be a promising product in the future including for driving under the influence.

A novel multi-walled carbon nanotube-based antibody conjugate for quantitative and semi-quantitative lateral flow assays.

In this study, the multi-walled carbon nanotubes (MWCNTs) were applied in lateral flow strips (LFS) for semi-quantitative and quantitative assays. Firstly, the solubility of MWCNTs was improved using various surfactants to enhance their biocompatibility for practical application. The dispersed MWCNTs were conjugated with the methamphetamine (MET) antibody in a non-covalent manner and then manufactured into the LFS for the quantitative detection of MET. The MWCNTs-based lateral flow assay (MWCNTs-LFA) exhibited an excellent linear relationship between the values of test line and MET when its concentration ranges from 62.5 to 1500 ng/mL. The sensitivity of the LFS was evaluated by conjugating MWCNTs with HCG antibody and the MWCNTs conjugated method is 10 times more sensitive than the one conjugated with classical colloidal gold nanoparticles. Taken together, our data demonstrate that MWCNTs-LFA is a more sensitive and reliable assay for semi-quantitative and quantitative detection which can be used in forensic analysis.

[The Study on Combined Screening Method for TBS and Cervical Cancer Cell's DNA Quantitative Analysis Based on Multi-Spectral Imaging Technology].

The traditional screening method of cervical cancer mainly involves TBS classification method and quantitative analysis method based on DNA, TBS screening method which has high diagnostic rate, but it needs experienced doctors to participate in the process with low sensitivity. Therefore, it is difficult to achieve early cervical cancer screening; cell's DNA quantitative analysis, only stained the nucleus, achieving a quantitative and automated analysis. Even with high sensitivity, the specificity is poor. So it is extremely necessary to realize the combination of screening for TBS and cell's DNA quantitative analysis, but the current TBS and DNA quantitative analysis combined screening method for the use of two different cell smear, time-consuming, laborious and very inconvenient, there is no screening method for cervical cancer on a combination of TBS and DNA quantitative analysis at home and abroad. This paper presents a method using TBS classification and DNA quantitative analysis on the same cell smear which was stained with Pap and Feulgen in order to solve the problem of the interference of the absorbance of DNA substance caused by multiple staining. a set of multi spectral imaging system and DNA absorbance peeling model are established based on linear multiple regression. With model solution, the real absorbance of the substance DNA was calculated, and the quantitative analysis of DNA was carried out. A pseudo color image is synthesized from 3 - band cell images with the close wavelength of RGB for TBS classification, so the organic combination of TBS and cell's DNA quantitative analysis is realized. Experiments show that the DNA quantitative analysis model of this method is stable, with small error and high diagnostic rate due to the fact that the pseudo color images used for TBS screening were bright, clear, and clear cytoplasm. Therefore, this method is very useful in the diagnosis and screening of cervical cancer.

[Study of Cervical Exfoliated Cell's DNA Quantitative Analysis Based on Multi-Spectral Imaging Technology].

The conventional cervical cancer screening methods mainly include TBS (the bethesda system) classification method and cellular DNA quantitative analysis, however, by using multiple staining method in one cell slide, which is staining the cytoplasm with Papanicolaou reagent and the nucleus with Feulgen reagent, the study of achieving both two methods in the cervical cancer screening at the same time is still blank. Because the difficulty of this multiple staining method is that the absorbance of the non-DNA material may interfere with the absorbance of DNA, so that this paper has set up a multi-spectral imaging system, and established an absorbance unmixing model by using multiple linear regression method based on absorbance's linear superposition character, and successfully stripped out the absorbance of DNA to run the DNA quantitative analysis, and achieved the perfect combination of those two kinds of conventional screening method. Through a series of experiment we have proved that between the absorbance of DNA which is calculated by the absorbance unmixxing model and the absorbance of DNA which is measured there is no significant difference in statistics when the test level is 1%, also the result of actual application has shown that there is no intersection between the confidence interval of the DNA index of the tetraploid cells which are screened by using this paper's analysis method when the confidence level is 99% and the DNA index's judging interval of cancer cells, so that the accuracy and feasibility of the quantitative DNA analysis with multiple staining method expounded by this paper have been verified, therefore this analytical method has a broad application prospect and considerable market potential in early diagnosis of cervical cancer and other cancers.

In vitro selection of DNA aptamers binding pesticide fluoroacetamide.

Fluoroacetamide (Mw = 77.06) is a lethal rodenticide to humans and animals which is still frequently abused in food storage somewhere in China. The production of antibodies for fluoroacetamide is difficult due to its high toxicity to animals, which limits the application of immunoassay method in poison detection. In this work, aptamers targeting N-fluoroacetyl glycine as an analog of fluoroacetamide were selected by a specific systematic evolution of ligands by exponential enrichment (SELEX) strategy. The binding ability of the selected aptamers to fluoroacetamide was identified using surface plasmon resonance (SPR)-based assay. The estimated KD values in the low micromolar range showed a good affinity of these aptamers to the target. Our work verified that the SELEX strategy has the potential for developing aptamers targeted to small molecular toxicants and aptamers can be employed as new recognition elements instead of antibodies for poison detection.

[Moving Mirror Scanning System Based on the Flexible Hinge Support].

In order to improve moving mirror drive of Fourier transform infrared spectrometer, we design a dynamic scanning system based on flexible hinge support. Using the flexible hinge support way and the voice coil motor drive mode. Specifically, Using right Angle with high accuracy high stability type flexible hinge support mechanism support moving mirror, dynamic mirror can be moved forward and backward driven by voice coil motor reciprocating motion, DSP control system to control the moving mirror at a constant speed. The experimental results show that the designed of moving mirror scanning system has advantages of stability direction, speed stability, superior seismic performance.

[Biological Process Oriented Online Fourier Transform Infrared Spectrometer].

An online Fourier Transform Infrared Spectrometer and an ATR (Attenuated Total Reflection) probe, specifically at the application of real time measurement of the reaction substrate concentration in biological processes, were designed. (1) The spectrometer combined the theories of double cube-corner reflectors and flat mirror, which created a kind of high performance interferometer system. The light path folding way was utilized to makes the interferometer compact structure. Adopting double cube-corner reflectors, greatly reduces the influence of factors in the process of moving mirror movement such as rotation, tilt, etc. The parallelogram oscillation flexible support device was utilized to support the moving mirror moves. It cancelled the friction and vibration during mirror moving, and ensures the smooth operation. The ZnSe splitter significantly improved the hardware reliability in high moisture environment. The method of 60° entrance to light splitter improves the luminous flux. (2) An ATR in situ measuring probe with simple structure, large-flux, economical and practical character was designed in this article. The transmission of incident light and the light output utilized the infrared pipe with large diameter and innerplanted-high plating membrane, which conducted for the infrared transmission media of ATR probe. It greatly reduced the energy loss of infrared light after multiple reflection on the inner wall of the light pipe. Therefore, the ATR probe obtained high flux, improved the signal strength, which make the signal detected easily. Finally, the high sensitivity of MCT (Mercury Cadmium Telluride) detector was utilized to realize infrared interference signal collection, and improved the data quality of detection. The test results showed that the system yields the advantages of perfect moisture-proof performance, luminous flux, online measurement, etc. The designed online Fourier infrared spectrometer can real-time measured common reactant substrates such as glycerin in the bioreactor under high quality. There is a large potential market, such as online analysis in biological, chemical testing and material analysis.

[Hadamard Transform NIR Spectrometer for the Biological Processes].

Monitoring the consumption of nutrients of biological process helps control the growth environment of the microbes. It ensures the microbes are always in the best growing conditions, so as to maximize the yield of the target product. To monitor the content of glycerol, methanol and glucose in yeast culture medium, a new NIR spectrometer was developed which is based on Hadamard Transform (HT)technique. It uses the Near IR probe, which was designed all by ourselves, to collect the spectral signals, and uses the Digital Micro-mirror Devices(DMD) to complete the coding and modulation of Hadamard template. With self-developed software, aiming at spectral acquisition and spectral processing, the spectrometer has realized the real-time monitoring. The designs of optical path, Near IR probe, hardware circuit and software modules are given. Through lots of experiments, it turns out that the value of stray light is 0.875% and the volatility is ±4.28% in this spectrometer. The spectrometer shows high precision in a series of tests which means it totally meets the requirements of monitoring the biological processes.

[AOTF-Based Imaging Spectrometer and Its Applications in the Identification of Metameric Targets].

For obtaining spectrum information and space distribution information of metameric targets at the same time, an AOTF-based imaging spectrometer was developed, which consists of a front imaging lens assembly, an AOTF filter imaging module, an AOTF driver, a plane array CCD, an image acquisition card and a PC. Under the control of the PC, a spectral image cube can be obtained by a fast wavelength scanning process, thereby the spectrum information of any point on the image is available. The developed imaging spectrometer, with a spectral range from 550-1,000 nm and a spectral resolution of 2.6 nm (@ 632 nm), and a less than 80 s switch time between any two wavelengths, has the characteristics of no mechanical moving part, low power dissipation and strong vibration resistance. The identification test of true and false roses and the information recovery experiment of altered physical evidence were carried out, The true and false roses were identified and the altered physical evidence was recovered, The experimental results showed that the imaging spectrometer has an excellent ability of identifying metameric targets, indicating a good application prospect.

Rapid analysis of diesel fuel properties by near infrared reflectance spectra.

In this study, based on near infrared reflectance spectra (NIRS) of 441 samples from four diesel groups (-10# diesel, -20# diesel, -35# diesel, and inferior diesel), three spectral analysis models were established by using partial least square (PLS) regression for the six diesel properties (i.e., boiling point, cetane number, density, freezing temperature, total aromatics, and viscosity) respectively. In model 1, all the samples were processed as a whole; in model 2 and model 3, samples were firstly classified into four groups by least square support vector machine (LS-SVM), and then partial least square regression models were applied to each group and each property. The main difference between model 2 and model 3 was that the latter used the direct orthogonal signal correction (DOSC), which helped to get rid of the non-relevant variation in the spectra. Comparing these three models, two results could be concluded: (1) models for grouped samples had higher precision and smaller prediction error; (2) models with DOSC after LS-SVM classification yielded a considerable error reduction compared to models without DOSC.

Determination of co-administrated opioids and benzodiazepines in urine using column-switching solid-phase extraction and liquid chromatography-tandem mass spectrometry.

Co-administration of opioids with benzodiazepines is very common around the world. A semi-automated method was developed for the determination of four opioids and two benzodiazepines as well as their metabolites (including glucuronide metabolites) in human urine, based on on-line column-switching-solid-phase extraction (CS-SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The CS-SPE was performed by loading 200µL of urine sample to an Oasis HLB cartridge. Detection was achieved using a LC-MS/MS system equipped with an electrospray ionization source (ESI). For unequivocal identification and confirmation, two selected reaction monitoring transitions were registered for each compound, and no co-elution of interferences was observed at the expected retention time. Significant ion suppressions were observed for most analytes during chromatographic runs, but isotope-labeled internal standards (ISs) were used and found to be useful to compensate for the determination error caused by the matrix effect. The assay's linearity ranged from 1-20ng/mL to 800-1000ng/mL for 23 compounds, except for lorazepam (LOR), whose linearity was in the range of 1-100ng/mL. This method showed to be precise and accurate. The relative standard deviation (RSD) % values of within-run precision, between-run precision and total precision were not greater than 10.4% (n=3), 12.9% (n=5) and 15.1% (n=15), respectively. Accuracy values were in the range of 87.5-110%. Limits of detection (LODs) ranged from 0.2ng/mL to 5ng/mL, and limits of quantification (LOQs) ranged from 1ng/mL to 20ng/mL. The method was applied to the assay of 12 samples from forensic cases, which exemplified the co-administration of benzodiazepines (BZDs) by some heroin abusers. This method was of high sensitivity, selectivity and reliability, minimum sample manipulation, semi-automation, and fairly high throughput (analysis time per sample was 20min). The method developed will be useful for the detection of co-administrated drugs and the study of the interactions of BDZs with opioids.

Screening of drugs of abuse and toxic compounds in human whole blood using online solid-phase extraction and high-performance liquid chromatography with time-of-flight mass spectrometry.

A novel method for the screening of 151 drugs of abuse and toxic compounds in human whole blood has been developed and validated by online solid-phase extraction with liquid chromatography coupled to time-of-flight mass spectrometry. Analytes were extracted and separated by using a fully automated online solid-phase extraction liquid chromatography system with total chromatographic run time of 26 min. Time-of-flight mass spectrometry screening of 151 drugs of abuse and toxic compounds was performed in a full-scan (m/z 50-800) mode using an MS(E) acquisition of molecular ions and fragment ions data at two collision energies (one was 6 eV and another one was in the range of 5-45 eV). The compounds were identified based on retention times and exact mass of molecular ions and fragment ions. The limit of detection ranged from 1 to 100 ng/mL and the recovery of the method ranged from 6.3 to 163.5%. This method is proved to be a valuable screening method allowing fast and specific identification of drugs in human whole blood.

[Development of a portable mid-infrared rapid analyzer for oil concentration in water based on MEMS linear sensor array].

Aiming at the existing problems such as weak environmental adaptability, low analytic efficiency and poor measuring repeatability in the traditional spectral oil analyzers, the present paper designed a portable mid-infrared rapid analyzer for oil concentration in water. To reduce the volume of the instrument, the non-symmetrical folding M-type Czerny-Turner optical structure was adopted in the core optical path. With a periodically rotating chopper, controlled by digital PID algorithm, applied for infrared light modulation, the modulating accuracy reached ±0.5%. Different from traditional grating-scanning spectrophotometers, this instrument used a fixed grating for light dispersion and avoided rotating error in the course of the measuring procedures. A new-type MEMS infrared linear sensor array was applied for modulated spectral signals detection, which improved the measuring efficiency remarkably. Optical simulation and experimental results indicate that the spectral range is 2 800 - 3 200 cm(-1), the spectral resolution is 6 cm(-1) (@3 130 cm(-1)), and the signal to noise ratio is up to 5 200 : 1. The acquisition time is 13 milliseconds per spectrogram, and the standard deviation of absorbance is less than 3 x 10(-3). These performances meet the standards of oil concentration measurements perfectly. Compared with traditional infrared spectral analyzers for oil concentration, the instrument demonstrated in this paper has many advantages such as smaller size, more efficiency, higher precision, and stronger vibration & moisture isolation. In addition, the proposed instrument is especially suitable for the environmental monitoring departments to implement real-time measurements in the field for oil concentration in water, hence it has broad prospects of application in the field of water quality monitoring.

[DNA aptamer selection in vitro for determining ketamine by FluMag-SELEX].

OBJECTIVE: To select specific DNA aptamer for determining ketamine by FluMag-SELEX. METHODS: Based on magnetic beads with tosyl surface modification as solid carrier and ketamine as target, a random ssDNA library with total length of 78 bp in vitro was compounded. After 13 rounds screening, DNA cloning and sequencing were done. Primary and secondary, structures were analyzed. The affinity, specificity and Kd values of selected aptamer were measured by monitoring the fluorescence intensity. RESULTS: Two ssDNA aptamers (Apt#4 and Apt#8) were successfully selected with high and specific abilities to bind ketamine as target with Kd value of 0.59 and 0.66 µmol/L. The prediction of secondary structure was main stem-loop and G-tetramer. The stem was the basis of stability of aptamer's structure. And loop and G-tetramer was the key of specific binding of ketamine. CONCLUSION: FluMag-SELEX can greatly improve the selection efficiency of the aptamer, obtain the ketamine-binding DNA aptamer, and develop a new method for rapid detection of ketamine.

Determination of ecgonine and seven other cocaine metabolites in human urine and whole blood by ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry.

Ecgonine is suggested to be a promising marker of cocaine (COC) ingestion. A combined mass spectrometry (MS) and tandem MS (MS/MS) method was developed to simultaneously determine ecgonine and seven other metabolites of cocaine in human urine and whole blood with ultra-high-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The compounds were extracted from as little as 100 µL of sample by solid-phase extraction with a 96-well µElution solid-phase extraction plate. The protonated molecules or fragment ions at accurate mass acquired in MS mode were used to quantify specific analytes, following by dedicated MS/MS identification. The assay was linear in the range from 5 to 50-100 ng/mL for urine samples, except for ecgonine methyl ester (10-200 ng/mL) and ecgonine (40-400 ng/mL), and was linear from 1-2 to 50 ng/mL for whole blood samples, except for ecgonine methyl ester (20-1,000 ng/mL) and ecgonine (40-2,000 ng/mL). The correlation coefficients were all greater than 0.99. The limits of detection ranged from 0.2 to 16 ng/mL, and the lower limits of quantification ranged from 1 to 40 ng/mL. The repeatability and intermediate precision were 18.1% or less. The accuracy was in the range from 80.0 to 122.9%, process efficiencies were in the range from 8.6 to 177.4%, matrix effects were in the range from 28.7 to 171.0%, and extraction recoveries were in the range from 41.0 to 114.3%, except for ecgonine (12.8% and 9.3% at low and high concentrations, respectively). This method was highly sensitive in comparison with previously published methods. The validated method was successfully applied to the analysis of real samples derived from forensic cases, and the results verified that, on the basis of data from four positive samples, ecgonine is a promising marker of cocaine ingestion.

[Design of a compact structure interferometer].

A novel interferometer system based on the combinations of cube-corner reflectors and fixed plane mirrors was designed, the moving mirror drive system was designed and analysed, and its governor PID algorithm was used to ensure that the movement of the moving mirror is collimated, uniform and smooth. The parameters of the optical system of the interferometer and the optical devices were described. Finally, after validation of the experiment, it was indicated that the wave number accuracy, resolution, signal to noise ratio and other key indicators can meet the needs of practical application.

[Testing method research for key performance indicator of imaging acousto-optic tunable filter (AOTF)].

Imaging AOTF is an important optical filter component for new spectral imaging instruments developed in recent years. The principle of imaging AOTF component was demonstrated, and a set of testing methods for some key performances were studied, such as diffraction efficiency, wavelength shift with temperature, homogeneity in space for diffraction efficiency, imaging shift, etc.

[Design of a high-throughput and wide-bandwidth near-infrared acousto-optic tunable filter].

The acousto-optic tunable filter (AOTF) is the most outstanding progress of near-infrared spectrometer since the 1990s. Restriction in working range and performance of the device exists due to the traditional single-transducer structure. The design of a near-infrared acousto-optic tunable filter with high-throughput and wide-bandwidth adopting a dual-transducer structure is reported in the present paper. By calculation and simulation based on the wave vector diagram which satisfies the parallel-tangents condition, the optimal cutting direction and cutting angle of the acousto-optic crystal, the length of the transducers and other best parameters were obtained. The tuning range of the filter is improved significantly while the resolution, diffraction efficiency and other parameters satisfy the requirements by making two transducers working at the high-frequency part and low-frequency part respectively. According to the testing results of the designed filter, the spectrum resolution is better than 15 nm and the diffraction efficiency is reaches to 41% with the tuning range of 900-2 400 nm.

[An interferometer design for Fourier transform infrared spectrometer].

A novel interferometer system based on the combinations of cube-corner reflectors and fixed plane mirrors was designed to improve the quality of spectra. It consists of a pair of cube corner reflectors, two fixed perpendicular plane mirrors and one beam splitter. By analyzing the modulation depth and phase error, the tilt and shearing of the cube corner reflectors, the deviation angle of cube corner reflector, the tilt of fixed plane mirrors and the deviation angle of two fixed plane mirrors were analyzed. It was proved that the tilt and shearing of the cube corner reflectors, and the deviation angle of two fixed plane mirrors, have no effects on the modulation depth and phase error of this new interferometer system, and the effect from the vibration, temperature fluctuations and other external environmental factors also can be effectively reduced, which can significantly improve the spectral resolution and quality. Through some experiments, it was found that the instrument has a simple structure, good sealing, high resolution, strong stability and other advantages

[A two-dimensional double dispersed hadamard transform spectrometer].

A kind of two-dimensional hadamard transform spectrometer was developed. A grating was used for chromatic dispersion of orders and a prism was used for spectral dispersion. Quite different from traditional CCD detection method, a digital micromirror device (DMD) was applied for optical modulation, and a simple point detector was used as the sensor. Compared with traditional two-dimensional spectrometer, it has the advantage of high resolution and signal-noise-ratio, which was proved by theoretical calculation and computer simulation.