An integrated microfluidic device for solid-phase extraction and spectrophotometric detection of opium alkaloids in urine samples

Recent advancements in the bioactive alkaloids analysis in plant and biological specimen: From the perspective of activity, sample preparation, and analytical method selection

Alkaloids are a diverse group of naturally occurring organic compounds. They are known for their significant pharmacological properties. This review provides an up-to-date analysis of bioactive alkaloids in plant and biological samples, emphasizing their biological activities, extraction techniques, and analytical methods. The study focuses on significant alkaloids such as morphine, codeine, vinblastine, vincristine, berberine, quinine, quinidine, caffeine, nicotine, ephedrine, and atropine, highlighting their chemical structures, therapeutic applications, and mechanisms of action. Recent advances in extraction methods, including conventional and modern green techniques such as supercritical fluid extraction, microwave-assisted extraction, and solid-phase microextraction, are discussed in detail. In addition, the review provides an overview of state-of-the-art analytical techniques used for alkaloid quantification, such as high-performance liquid chromatography, liquid chromatography-mass spectrometry, and novel spectroscopic methods. Emphasis is placed on the challenges associated with alkaloid analysis, including matrix effects, stability, and structural diversity. The results contribute to the growing body of knowledge in alkaloid research, providing insights into their potential therapeutic applications and analytical improvements for more accurate and efficient detection in various biological and plant matrices.

A near-infrared plasmonic biosensor for detection of morphine and codeine in biological samples based on the end-to-end assembly of modified gold nanorods

The analytical determination of opiates in biological samples is a critical mission and remains a challenge for almost all judicial and clinical drug testing panels due to their high abuse potential. Based on the high sensitivity of the longitudinal surface plasmon resonance (LSPR) peak of gold nanorods (AuNRs), we successfully developed a novel and simple refractive index sensing platform for detection of morphine (MOR) and codeine (COD) by means of 2-amino-5-mercapto-1,3,4-thiadiazole functionalized gold nanorods (AMTD-AuNRs) in aqueous solution, which is, to the best of our knowledge, the first report on the assay of MOR and COD using AuNRs. AMTD molecules strongly anchor onto the tips of AuNRs via the mercapto group and subsequent hydrogen-bonding interactions between AMTD and the analytes induced end-to-end chain assembly of AuNRs and a consequent decrease of the LSPR absorption band at 850 nm along with a bathochromic shift and emergence of a new hybridized plasmon mode at 1050 nm which was characterized using a Vis-NIR spectrophotometer. After systematic optimization, the absorbance ratio (A1050/A850) was proportional to the concentration of MOR in the ranges of 0.08-5 μM and 0.2-8 μM for COD without any significant effect from possible interferents. Furthermore, detection limits of 40 and 62 nM were achieved for MOR and COD, respectively, which are much lower than the cut-off level of 2000 ng mL-1 for opiates in urine samples set by the Substance and Abuse Mental Health Services Administration (SAMHSA). Eventually, as proof-of-applicability, human urine and blood serum samples spiked with MOR and COD were analyzed and excellent recoveries ranging from 94.4 to 108.9% were obtained, demonstrating the successful applicability of the designed refractive index probe in real biological specimens.

Sorptive tape-spray tandem mass spectrometry using aluminum foil coated with mixed-mode microparticles

Direct mass spectrometry (MS) is an exciting strategy in bioanalysis, enabling rapid decision-making in different scenarios. Its application is usually hindered by matrix effects and the typically low concentration of the target compounds in the biofluids. In this sense, combining a previous sample preparation step minimizes or removes these shortcomings. This article describes sorptive tape-spray tandem mass spectrometry (STS-MS/MS) based on mixed-mode particles as a strategy to combine sample preparation and MS analysis in a single device. The technique uses a sorptive tape (ST) consisting of mixed-mode polymeric microparticles (combining ionic exchange and hydrophobic interactions) coated over aluminum foil in a spatial controlled way. The tapes act as the sorptive phases to isolate the analytes from the sample matrix and substrates for STS-MS/MS. The performance of the technique has been evaluated by developing a method to determine codeine in saliva as proof of concept. The affordability of the STs elements allows the preparation of many individual phases at low cost so that several samples can be extracted simultaneously, thus increasing the sample throughput. The extraction variables were optimized following a multivariate approach. Working under the optimum conditions, the limit of detection was 0.3 μg L-1, while the intraday precision, calculated as relative standard deviation (RSD) at three concentration levels, was better than 9.4 %. The accuracy, expressed as relative recovery, was in the range of 78-98 %. The method was also applied to the analysis of real samples. Despite being a powerful strategy, the direct combination of microextraction to MS is not always affordable in all laboratories. For this reason, the STs were also combined with commercial liquid chromatography-MS working under the direct infusion mode to demonstrate the usefulness of the ST in classical extraction workflows.

Application of microfluidic technologies in forensic analysis

The application of microfluidic technology in forensic medicine has steadily expanded over the last two decades due to the favorable features of low cost, rapidity, high throughput, user-friendliness, contamination-free, and minimum sample and reagent consumption. In this context, bibliometric methods were adopted to visualize the literature information contained in the Science Citation Index Expanded from 1989 to 2022, focusing on the co-occurrence analysis of forensic and microfluidic topics. A deep interpretation of the literature was conducted based on co-occurrence results, in which microfluidic technologies and their applications in forensic medicine, particularly forensic genetics, were elaborated. The purpose of this review is to provide an impartial evaluation of the utilization of microfluidic technology in forensic medicine. Additionally, the challenges and future trends of implementing microfluidic technology in forensic genetics are also addressed.

Optical Properties of Electrospun Nanofiber Mats

Electrospun nanofiber mats are usually applied in fields where their high specific surface area and small pore sizes are important, such as biotechnology or filtration. Optically, they are mostly white due to scattering from the irregularly distributed, thin nanofibers. Nevertheless, their optical properties can be modified and become highly important for different applications, e.g., in sensing devices or solar cells, and sometimes for investigating their electronic or mechanical properties. This review gives an overview of typical optical properties of electrospun nanofiber mats, such as absorption and transmission, fluorescence and phosphorescence, scattering, polarized emission, dyeing and bathochromic shift as well as the correlation with dielectric constants and the extinction coefficient, showing which effects may occur and can be measured by which instruments or used for different applications.

Polyaniline and Polyaniline-Based Materials as Sorbents in Solid-Phase Extraction Techniques

Polyaniline (PANI) is one of the best known and widely studied conducting polymers with multiple applications and unique physicochemical properties. Due to its porous structure and relatively high surface area as well as the affinity toward many analytes related to the ability to establish different types of interactions, PANI has a great potential as a sorbent in sample pretreatment before instrumental analyses. This study provides an overview of the applications of polyaniline and polyaniline composites as sorbents in sample preparation techniques based on solid-phase extraction, including conventional solid-phase extraction (SPE) and its modifications, solid-phase microextraction (SPME), dispersive solid-phase extraction (dSPE), magnetic solid-phase extraction (MSPE) and stir-bar sorptive extraction (SBSE). The utility of PANI-based sorbents in chromatography was also summarized. It has been shown that polyaniline is willingly combined with other components and PANI-based materials may be formed in a variety of shapes. Polyaniline alone and PANI-based composites were successfully applied for sample preparation before determination of various analytes, both metal ions and organic compounds, in different matrices such as environmental samples, food, human plasma, urine, and blood.

Electrospun Conducting Polymers: Approaches and Applications

Inherently conductive polymers (CPs) can generally be switched between two or more stable oxidation states, giving rise to changes in properties including conductivity, color, and volume. The ability to prepare CP nanofibers could lead to applications including water purification, sensors, separations, nerve regeneration, wound healing, wearable electronic devices, and flexible energy storage. Electrospinning is a relatively inexpensive, simple process that is used to produce polymer nanofibers from solution. The nanofibers have many desirable qualities including high surface area per unit mass, high porosity, and low weight. Unfortunately, the low molecular weight and rigid rod nature of most CPs cannot yield enough chain entanglement for electrospinning, instead yielding polymer nanoparticles via an electrospraying process. Common workarounds include co-extruding with an insulating carrier polymer, coaxial electrospinning, and coating insulating electrospun polymer nanofibers with CPs. This review explores the benefits and drawbacks of these methods, as well as the use of these materials in sensing, biomedical, electronic, separation, purification, and energy conversion and storage applications.

Simultaneous spectrophotometric determination of drug components from their dosage formulations

Spectrophotometry is a quick and reliable method for determining the composition of a variety of complex drug mixtures. Several mathematical models are available for the resolution of complex multicomponent UV spectra. UV spectrophotometric methods have the inherent capacity to resolve the interlaced spectra of complex mixtures quickly and appropriately, particularly for quantitative determination of components of mixture where several costly tools are not available. These methods also have the benefit of lower operational costs as they are operated using lesser amounts of analytical grade solvents and generate less waste. In this review, we discussed the theoretical background of different UV spectrometric methods for quantitative analysis of drug mixtures. The main focus of this review is to describe and report applications of extended Beer's law-based multicomponent analysis and to highlight the recent developments in the simultaneous determination of drug components from their complex mixtures.

Recent Developments in Microfluidic Paper-based Analytical Devices for Pharmaceutical Analysis

In the last decade, due to the global increase in diseases, drugs for biomedical applications have increased dramatically. Therefore, there is an urgent need for analytical tools to monitor, treat, investigate, and control drug compounds in diverse matrices. The new and challenging task has been looking for simple, low-cost, rapid, and portable analytical platforms. The development of microfluidic paper-based analytical devices (μPADs) has garnered immense attention in many analytical applications due to the benefit of cellulose structure. It can be functionalized and serves as an ideal channel and scaffold for the transportation and immobilization of various substances. Microfluidic technology has been considered an effective tool in pharmaceutical analysis that facilitates the quantitative measurement of several parameters on cells or other biological systems. The μPADs represent unique advantages over conventional microfluidics, such as the self-pumping capability. They have low material costs, are easy to fabricate, and do not require external power sources. This review gives an overview of the current designs in this decade for μPADs and their respective application in pharmaceutical analysis. These include device designs, choice of paper material, and fabrication techniques with their advantages and drawbacks. In addition, the strategies for improving analytical performance in terms of simplicity, high sensitivity, and selectivity are highlighted, followed by the application of μPADs design for the detection of drug compounds for various purposes. Moreover, we present recent advances involving μPAD technologies in the field of pharmaceutical applications. Finally, we discussed the challenges and potential of μPADs for the transition from laboratory to commercialization.

Recent progress of microfluidic technology for pharmaceutical analysis

In recent years, the progress of microfluidic technology has provided new tools for pharmaceutical analysis and the proposal of pharm-lab-on-a-chip is appealing for its great potential to integrate pharmaceutical test and pharmacological test in a single chip system. Here, we summarize and highlight recent advances of chip-based principles, techniques and devices for pharmaceutical test and pharmacological/toxicological test focusing on the separation and analysis of drug molecules on a chip and the construction of pharmacological models on a chip as well as their demonstrative applications in quality control, drug screening and precision medicine. The trend and challenge of microfluidic technology for pharmaceutical analysis are also discussed and prospected. We hope this review would update the insight and development of pharm-lab-on-a-chip.

Self-Adhesion Conductive Sub-micron Fiber Cardiac Patch from Shape Memory Polymers to Promote Electrical Signal Transduction Function

Myocardial infarction (MI) constitutes the first cause of morbidity and mortality in our life, so using highly conductive and elastic materials to produce an engineered cardiac patch is an effective way to improve the myocardium infarction area function. Here, shape memory polymers of the polyurethane/polyaniline/silicon oxide (PU/PANI/SiO₂) electrospinning sub-micron fiber patch were precisely produced in the case of the hydrogen bonding effect and interaction between the carboxyl groups to provide compatibility, phase mixing/miscibility, and stability. The sub-micron fiber patch prepared by our group has some remarkable characteristics, such as sub-micron fibers, 3D porous structure, special thickness to simulate the extracellular matrix (ECM), elastic deformation, good properties in conducting weak electrical signals, stability to maintain the whole structure, and self-adhesion. This sub-micron fiber material has been proven to be effective, easy, and reliable. Through precise design of the material system, structure regulation, and performance optimization, the aim is to produce a sub-micron fiber cardiac patch to simulate the myocardium ECM and improve conductive signal transduction for potential MI therapy.

Developing an integrated microfluidic and miniaturized electrochemical biosensor for point of care determination of glucose in human plasma samples

A cost-effective, point of care (POC) device based on highly oriented CNT arrays was developed as an electrochemical assay for real-time and sensitive detection of glucose in complex samples. A low-cost, microcontroller-based potentiostat consisting of Arduino Due and LMP9100-EVM was developed to perform electrochemical measurements such as cyclic voltammetry (CV) and amperometry. A syringe pump based on open-source electronics was designed to direct the flow through a microfluidic chip. Vertically aligned carbon nanotube (VACNT) sensor arrays, in combination with the miniature potentiostat and the syringe pumps, were utilized as a POC device for the rapid and accurate detection of glucose. The structure and morphology of samples were characterized by field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR). CV as well as electrochemical impedance spectroscopy (EIS) was performed to investigate the electrochemical behavior of the electrode with respect to different diffusion regimes. The mediator-less biosensor had a limit of detection of 23 μM and sensitivity of 1462 μA mM-1 cm-2 and 1050 μA mM-1 cm-2 at the linear range of 1.2-7.8 mM and 7.8-11.2 mM, respectively. The presence of other biological compounds such as uric acid (UA) and ascorbic acid (AA) did not interfere with the detection of glucose. Finally, the designed POC device was successfully applied for the determination of glucose in human blood plasma samples.

Dual Naked-Eye and Optical Chemosensor for Morphine Detection in Biological Real Samples Based on Cr(III) Metal-Organic Framework Nanoparticles

The analytical detection and quantification of abuse drugs such as morphine (MOR) in biological samples are vital missions and remains to attract challenges for forensic toxicology, law enforcement, world antidoping organization, and social health fields. MOR, a benchmark analgesic drug known as "pain killer", is one of the powerful opioid medications for relieving pain, and overdose of MOR is toxic. In this article, novel promising chromium metal-organic framework nanoparticles [Cr(III)-MOF-NPs] were produced via facile synthesis and characterized using high-resolution transmission electron microscopy, field-emission scanning electron microscopy/energy-dispersive X-ray spectroscopy, mass spectrometry, X-ray photoelectron spectroscopy, elemental analysis, UV-vis, Fourier transform infrared, and thermogravimetry/differential scanning calorimetry, as well as photoluminescence (PL) investigation and magnetic properties. The PL study results revealed that the Cr(III)-MOF-NPs exhibited an emission band at 593 nm. The Cr(III)-MOF-NPs could be used in fast, selective, and sensitive MOR detection and quantification. Under the optimum experimental conditions, with the addition of MOR, a blueshift from 593 to 566 nm occurred with a remarkable PL intensity enhancement, and the color changed from brown to yellow (visually/naked-eye detection). The Cr(III)-MOF-NPs optical chemosensor exhibited a stable response for MOR in a concentration range between 0.1 and 350 nM. The detection and quantification limits were 0.167 and 0.443 nM, respectively, with a correlation coefficient (r 2) of 0.96. The developed PL chemosensor showed high selectivity for MOR over other competing interfering matrices. Moreover, the ultrasensitive chemosensor was extensively used for the determination of MOR spiked in different real samples (serum and urine samples) with acceptable recoveries and satisfactory results.

3D Printed Microfluidic Devices for Solid-Phase Extraction and On-Chip Fluorescent Labeling of Preterm Birth Risk Biomarkers

Solid-phase extraction (SPE) is a general preconcentration method for sample preparation that can be performed on a variety of specimens. The miniaturization of SPE within a 3D printed microfluidic device further allows for fast and simple extraction of analytes while also enabling integration of SPE with other sample preparation and separation methods. Here, we present the development and application of a reversed-phase lauryl methacrylate-based monolith, formed in 3D printed microfluidic devices, which can selectively retain peptides and proteins. The effectiveness of these SPE monoliths and 3D printed microfluidic devices was tested using a panel of nine preterm birth biomarkers of varying hydrophobicities and ranging in mass from 2 to 470 kDa. The biomarkers were selectively retained, fluorescently labeled, and eluted separately from the excess fluorescent label in 3D printed microfluidic systems. These are the first results demonstrating microfluidic analysis processes on a complete panel of preterm birth biomarkers, an important step toward developing a miniaturized, fully integrated analysis system.