Gold Fluorescence Nanoparticles for Enhanced SERS Detection in Biomedical Sensor Applications: Current Trends and Future Directions.

Nanotechnology has emerged as a pivotal tool in biomedical research, particularly in developing advanced sensing platforms for disease diagnosis and therapeutic monitoring. Since gold nanoparticles are biocompatible and have special optical characteristics, they are excellent choices for surface-enhanced Raman scattering (SERS) sensing devices. Integrating fluorescence characteristics further enhances their utility in real-time imaging and tracking within biological systems. The synergistic combination of SERS and fluorescence enables sensitive and selective detection of biomolecules at trace levels, providing a versatile platform for early cancer diagnosis and drug monitoring. In cancer detection, AuNPs facilitate the specific targeting of cancer biomarkers, allowing for early-stage diagnosis and personalized treatment strategies. The enhanced sensitivity of SERS, coupled with the tunable fluorescence properties of AuNPs, offers a powerful tool for the identification of cancer cells and their microenvironment. This dual-mode detection not only improves diagnostic accuracy but also enables the monitoring of treatment response and disease progression. In drug detection, integrating AuNPs with SERS provides a robust platform for identifying and quantifying pharmaceutical compounds. The unique spectral fingerprints obtained through SERS enable the discrimination of drug molecules even in complex biological matrices. Furthermore, the fluorescence property of AuNPs makes it easier to track medication distribution in real-time, maximizing therapeutic effectiveness and reducing adverse effects. Furthermore, the review explores the role of gold fluorescence nanoparticles in photodynamic therapy (PDT). By using the complementary effects of targeted drug release and light-induced cytotoxicity, SERS-guided drug delivery and photodynamic therapy (PDT) can increase the effectiveness of treatment against cancer cells. In conclusion, the utilization of gold fluorescence nanoparticles in conjunction with SERS holds tremendous potential for revolutionizing cancer detection, drug analysis, and photodynamic therapy. The dual-mode capabilities of these nanomaterials provide a multifaceted approach to address the challenges in early diagnosis, treatment monitoring, and personalized medicine, thereby advancing the landscape of biomedical applications.

Determination of Methamphetamine by High-Performance Liquid Chromatography in Odor-Adsorbent Material Used for Training Drug-Detection Animals.

The objective of the present report was to develop and validate a simple, sensitive, and selective analytical method for the determination of methamphetamine in an odor-adsorbent material (gauze) which was used to improve and standardize the training method used for drug-detection animals. High-performance liquid chromatography (HPLC) was performed using a Spherisorb ODS2 C18 column (200 mm × 4.6 mm, 5 µm), with a mobile phase consisting of a 0.25% methanol/triethylamine aqueous solution (V:V = 20:80), the pH of which was adjusted to 3.1 using glacial acetic acid, at a flow rate of 1.0 mL/min. The column temperature was 25 °C, and the detection of the analytes was performed at a wavelength of 260 nm. Methamphetamine showed good linearity (R2 = 0.9999) in the range of 4.2~83.2 mg/mL. The stability of the test material was good over 24 h. The precision of the method was good, with an average spiked recovery of 86.2% and an RSD of 2.9%. The methamphetamine content in the gauze sample was determined to be 7.8 ± 2.2 µg/sample. A high-performance liquid chromatography (HPLC) method was optimized and validated for the determination of methamphetamine in adsorbent materials (gauze). Validation data in terms of specificity, linearity, the limit of detection and the limit of quantification, reproducibility, precision, stability, and recovery indicated that the method is suitable for the routine analysis of methamphetamine in adsorbent materials (gauze) and provided a basis for training drug-detection animals.

Nanoarchitectonics for Abused-Drug Biosensors.

Rapid, accessible, and highly accurate biosensors for the detection of addictive and abused drugs are needed to reduce the adverse personal and societal impacts of addiction. Modern sensors that utilize next-generation technologies, e.g., nanobiotechnology and nanoarchitectonics, have triggered revolutionary progress in the field as they allow accurate detection and tracking of trace levels of major classes of drugs. This paper reviews advances in the field of biosensors for the detection of commonly abused drugs, both prescribed such as codeine and morphine, and illegal narcotics like cocaine.

Recent Advances in the Use of Surface-Enhanced Raman Scattering for Illicit Drug Detection.

The rapid increase in illicit drug use and its adverse health effects and socio-economic consequences have reached alarming proportions in recent years. Surface-enhanced Raman scattering (SERS) has emerged as a highly sensitive analytical tool for the detection of low dosages of drugs in liquid and solid samples. In the present article, we review the state-of-the-art use of SERS for chemical analysis of illicit drugs in aqueous and complex biological samples, including saliva, urine, and blood. We also include a review of the types of SERS substrates used for this purpose, pointing out recent advancements in substrate fabrication towards quantitative and qualitative detection of illicit drugs. Finally, we conclude by providing our perspective on the field of SERS-based drug detection, including presently faced challenges. Overall, our review provides evidence of the strong potential of SERS to establish itself as both a laboratory and in situ analytical method for fast and sensitive drug detection and identification.

Evaluation of Current Hazardous Drug Exposure Control in Community Pharmacy.

Purpose: To evaluate effectiveness of current hazardous drug exposure control practices in community pharmacies through identification of commonly contaminated surfaces. We also assessed the decontamination effectiveness of 5 different cleaning agents. Methods: This study was prospective and nonrandomized and conducted in 2 phases. In phase 1, 15 common areas used in the dispensing process were tested at each of 4 pharmacies in Toronto Ontario, Canada. Testing was conducted using the BD® HD Check System, a rapid, point-of-care, hazardous drug detection system that is able to identify contamination with methotrexate (MTX) and cyclophosphamide (CYP) and doxorubicin. In phase 2, 5 different cleaning agents (70% isopropyl alcohol, Lysol® spray, Ecolab® retail multiquat sanitizer, Ecolab retail multisurface and glass cleaner with peroxide, and Ecolab QSR heavy-duty degreaser) were tested for their ability to eliminate contamination. Results: All 4 pharmacies tested positive for contamination with MTX (25.8% of surfaces). Contamination with CYP was less frequent, with only 3 sites and 18.2% of surfaces testing positive. Of the 5 cleaning agents tested, only Ecolab QSR heavy-duty degreaser was able to eliminate contamination with MTX. None of the agents were successful against CYP. Conclusions: The results illustrate an unacceptable prevalence of hazardous drug contamination in community pharmacy settings. The BD HD Check System can serve to rapidly detect common high-risk areas for surface contamination. Decontamination protocols against MTX may include Ecolab QSR heavy-duty degreaser. Novel agents must be identified to remove contamination caused by CYP.

Sharing Objective Measures of Adherence to a Vaginal Microbicide Promotes Candor About Actual Use and Bolsters Motivation to Prevent HIV.

Discrepancies between self-reported and actual adherence to biomedical HIV interventions is common and in clinical trials can compromise the integrity of findings. One solution is to monitor adherence biomarkers, but it is not well understood how to navigate biomarker feedback with participants. We surveyed 42 counselors and interviewed a subset of 22 to characterize their perspectives about communicating with participants about residual drug levels, an objective marker of adherence, within MTN-025/HOPE, a Phase 3b clinical trial of a vaginal ring to prevent HIV. When biomarkers indicated low drug levels that mismatched high adherence by self-report, counselors encountered barriers to acceptance and comprehension among participants. However, discrepancies between low self-report and higher drug levels generally stimulated candor. Women recollected times they had not used the product and disclosed problems that counselors thought might otherwise have remained forgotten or concealed. Navigating conversations toward HIV prevention was easier at mid-range drug levels and when women indicated motivation to prevent HIV. Ratings of residual drug level offered a somewhat objective measure of adherence and protection that counselors perceived as meaningful to participants and as a valuable catalyst for broaching conversation about HIV prevention. However, communication about drug levels required that counselors navigate emotional barriers, respond skillfully to questions about accuracy, and pivot conversations non-judgmentally away from numerical results and toward the priority of HIV prevention. Findings suggest a role for biomarker feedback in future clinical trials as well as other clinical contexts where biomarkers may be monitored, to motivate disclosure of actual adherence and movement toward HIV prevention.Clinical Trial Number NCT02858037.

RESUMEN: Discrepancias entre la adherencia auto-reportada y la verdadera a intervenciones biomédicas de VIH pueden comprometer los ensayos clínicos. Una solución es monitorear la adherencia por medio de ensayos biológicos, pero no se entiende bien cómo comunicar estas medidas a los participantes. En MTN-025/HOPE, un ensayo fase 3b de un anillo vaginal para prevenir VIH, encuestamos a 42 consejeros de adherencia y entrevistamos a un subconjunto de 22 para caracterizar sus perspectivas sobre comunicar una medida objetiva de adherencia al anillo, el nivel residual de droga (RDL por sus siglas en inglés). Los consejeros reportaron que los participantes apreciaron la retroalimentación del RDL como una indicación de su protección de VIH. Niveles más altos de droga estimularon euforia y alivio mientras niveles mas bajos resultaron en desilusión. Una postura no crítica y el apoyo a la autonomía de elegir otras alternativas al anillo promovieron divulgación de las razones por la falta de adherencia. Hablar del monitoreo de RDL como "protección" en vez de "adherencia" ayudó a cambiar el enfoque desde resultados numéricos hasta la meta mayor del ensayo de prevenir el VIH. Personalizar la retroalimentación de medidas objetivas de adherencia requiere una conversación cuidadosa para minimizar las actitudes defensivas. La retroalimentación personalizada también se puede implementar de forma que motive la divulgación de la falta de adherencia y evoque un compromiso a prácticas de prevención. Enfatizar las motivaciones de las mujeres a prevenir el VIH, en vez de los resultados numéricos, puede incentivar a los usuarios consistentes a continuar y a los usuarios inconsistentes a usar métodos alternativos de prevención.

Ultrasensitive covalently-linked Aptasensor for cocaine detection based on electrolytes-induced repulsion/attraction of colloids.

A quick and easy colorimetric sensor based on gold nanoparticles (GNPs) and aptamers for the detection of cocaine was developed. The sensor was named as 'GAPTA' and showed extremely interesting results regarding cocaine detection with a sensitivity to doses of 0.2 nM. The experimental approach consisted of creating a conjugate between GNPs (10 nm size) and aptamers as a sensing base with the addition of an electrolyte (NaCl) that plays the role of aggregation inducer. In the absence of the aptamer, the electrolyte was able to induce aggregation of the GNPs turning the color of the solution from red to blue while the presence of the aptamer is able to hinder the charges attraction and protects the GNPs from aggregating. The optimization of the aptamer and electrolyte concentration was determined to be 118 nM and 55 mM, respectively, and the resultant GAPTA sensor had a detection limit of 0.97 nM. Furthermore, the selectivity of the platform was tested in the presence of different interferents and showed a specific response towards cocaine while interference ranged between 20 and 40%. The applicability of the GAPTA biosensor was tested on synthetic saliva and demonstrated a sensitivity range between 0.2 and 25 nM. These results suggest the potential of the current colorimetric sensor in abuse drugs screening and creates a stable base for new routine platforms for biomedical and toxicology applications. Graphical abstract.

Multilayer Gold-Silver Bimetallic Nanostructures to Enhance SERS Detection of Drugs.

Surface-enhanced Raman scattering (SERS) is a widely used technique for drug detection due to high sensitivity and molecular specificity. The applicability and selectivity of SERS in the detection of specific drug molecules can be improved by gathering information on the specific interactions occurring between the molecule and the metal surface. In this work, multilayer gold-silver bimetallic nanorods (Au@Ag@AuNRs) have been prepared and used as platforms for SERS detection of specific drugs (namely promethazine, piroxicam, furosemide and diclofenac). The analysis of SERS spectra provided accurate information on the molecular location upon binding and gave some insight into molecule-surface interactions and selectivity in drug detection through SERS.

A screen-printed electrode modified with tungsten disulfide nanosheets for nanomolar detection of the arsenic drug roxarsone.

A sensitive electrochemical (voltammetric; DPV) sensor has been developed for the determination of coccidiostat drug (roxarsone) based on the use of an SPCE (screen-printed carbon electrode) modified with tungsten disulfide nanosheets (WS2 NSs). The electrochemical detection of roxarsone on the WS2-modified SPCE was examined by electrochemical strategies. XPS, XRD, Raman, SEM, TEM, EDS and EIS were used to characterize the nanosheets. The effects of scan rate, pH values (phosphate buffer) and buffer concentration were optimized. A selective roxarsone sensor was developed that works best at -0.64 V (vs. Ag/AgCl) and performs much better than the bare SPCE. Features include (a) a wider linear range (0.05 to 490 µM), (b) a nanomolar detection limit (0.03 µM) and (c) high sensitivity (29 µA·µM-1·cm-2). The modified SPCEs have been successfully applied to the determination of roxarsone in spiked meat samples where they gave high accuracy and good recoveries. Graphical abstract Synthesis of WS2 nanosheets and electrochemical detection of roxarsone.

A nanocomposite consisting of MnO2 nanoflowers and the conducting polymer PEDOT for highly sensitive amperometric detection of paracetamol.

An electrochemical sensor for paracetamol is described that consists of a glassy carbon electrode (GCE) that was modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with MnO2 nanoflowers. The hydrothermally synthesized MnO2 nanoflowers possess a large surface area and can be doped into PEDOT through electrochemical deposition to form a conducting polymer nanocomposite. The nanoflowers are shown to be uniformly distributed within the nanocomposite as revealed by elemental mapping analysis. The nanocomposite displays excellent catalytic activity toward the electrochemical oxidation of paracetamol. The modified GCE, best operated at a working potential of around 0.37 V (vs. SCE) has a linear response in 0.06 to 435 µM paracetamol concentration range and a very low limit of detection (31 nM at a signal-to-noise ratio of 3). The sensor exhibits excellent reproducibility and stability, and satisfying accuracy for paracetamol detection in pharmaceutical samples. Graphical abstract A highly sensitive electrochemical sensor capable of detecting paracetamol with a limit of detection down to 31 nM was developed based on MnO2 nanoflowers doped conducting polymer PEDOT.

How Presentation of Drug Detection Results Changed Reports of Product Adherence in South Africa, Uganda and Zimbabwe.

Accurate estimates of study product use are critical to understanding and addressing adherence challenges in HIV prevention trials. The VOICE trial exposed a significant gap between self-reported adherence and drug detection. The VOICE-D qualitative study was designed to better understand non-adherence during VOICE, and was conducted in 2 stages: before (stage 1) and after (stage 2) drug detection results were provided to participants. Transcripts from 44 women who participated in both stages were analysed to understand the effect of presenting drug detection data on narratives of product use. Thirty-six women reported high adherence in stage 1, yet admitted non-use in stage 2, three reported high adherence in both stages (contrary to their drug detection results) and five had consistent responses across both stages and drug results. Presenting objective measures of use may facilitate more accurate product use reporting and should be evaluated in future prevention trials.

Improving the Surface-Enhanced Raman Scattering Performance of Silver Nanodendritic Substrates with Sprayed-On Graphene-Based Coatings.

This study examines the improvements in surface-enhanced Raman scattering (SERS) performance achieved when silver nanodendritic structures are coated with various graphene-based materials, namely graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanoplatelets (GNPs). The tests are performed on our unique SERS-active substrates, prepared on the surface of planar microelectrode chips using an electric field-guided Ag nanoparticle assembly process. The graphene-based materials are introduced into the substrate by means of an in-house spray-coating technique. The SERS enhancement effect of each coating is examined as a function of spray nozzle passes (N) and optimal values are identified for each coating type. The enhancements found for GO, rGO, and GNP (6⁻9 graphene layers thick) coatings are 2.3 (N = 25), 2.5 (N = 5), and 1.6 (N = 1), respectively. Additionally, in comparison with their uncoated counterparts, substrates coated with rGO (N = 5) are shown to enhance the intensity of the methamphetamine (5 ppb) spectrum in artificial saliva by approximately 3-fold. Overall, it can be concluded that the introduction of GO or rGO to the SERS substrate using spray-coating, a simple and also scalable method, can produce substantial SERS performance enhancement.

Acceptability of drug detection monitoring among participants in an open-label pre-exposure prophylaxis study.

In the world of HIV pre-exposure prophylaxis (PrEP) research, there is emerging interest in providing study participants with pharmacokinetic results from drug level testing to guide adherence counseling. The iPrEx randomized control trial was the first study to produce meaningful results of PrEP in humans. In the iPrEx open-label extension (OLE) study, blood plasma samples collected in the first 12 weeks of study participation were tested for the presence of tenofovir/emtricitabine--the drugs which compromise PrEP. Study clinicians shared results (detectable/undetectable) with participants at their 24-week visit. We evaluated the acceptability of receiving these results among a subset of iPrEx OLE participants. We conducted in-depth interviews (n = 59) with participants (those with and those without drug detected) enrolled in Boston, Chicago, and San Francisco to assess their experiences with receiving drug detection feedback. Incorporating drug detection results into the clinical study visit was well received and no negative reactions were expressed. For about half of participants, receiving their drug detection lab result was useful while for others it was not important. In a few cases, no drug detected results led to increased efforts to take PrEP consistently and in most cases enhanced open discussion of missed doses. Participants reported a desire for greater specificity, particularly quantitative drug levels needed for protection. We recommend exploring strategies to increase the salience of drug level results, including using feedback to target adherence counseling, and reducing the time between specimen collection, testing, and receipt of results. Future studies should evaluate the feasibility and impact of providing more specific quantitative drug levels using biomarkers of longer term PrEP exposure, i.e., hair/dried blood spots.

Continuous re-hyperpolarization of nuclear spins using parahydrogen: theory and experiment.

The continuous re-hyperpolarization of nuclear spins in the liquid state by means of parahydrogen (para-H2) and chemical exchange at low magnetic fields was recently discovered and offers intriguing perspectives for many varieties of magnetic resonance. In this contribution, we provide a theoretical assessment of this effect and compare the results to experimental data. A distinct distribution of polarization is found, which shares some features with experimental data and, interestingly, does not directly correspond to the loss of the singlet order of para-H2. We derived expressions for the magnetic field and para-H2-substrate interaction time, for which the polarization transfer is maximal. This work sheds light onto the effect of continuous hyperpolarization and elucidates the underlying mechanism, which may facilitate the development of an optimized catalyst. As an application, continuous hyperpolarization may enable highly sensitive nuclear magnetic resonance at very low magnetic fields, for example, for the cost-efficient screening of drugs.

Headspace analysis of new psychoactive substances using a Selective Reagent Ionisation-Time of Flight-Mass Spectrometer.

The rapid expansion in the number and use of new psychoactive substances presents a significant analytical challenge because highly sensitive instrumentation capable of detecting a broad range of chemical compounds in real-time with a low rate of false positives is required. A Selective Reagent Ionisation-Time of Flight-Mass Spectrometry (SRI-ToF-MS) instrument is capable of meeting all of these requirements. With its high mass resolution (up to m/Δm of 8000), the application of variations in reduced electric field strength (E/N) and use of different reagent ions, the ambiguity of a nominal (monoisotopic) m/z is reduced and hence the identification of chemicals in a complex chemical environment with a high level of confidence is enabled. In this study we report the use of a SRI-ToF-MS instrument to investigate the reactions of H3O+, O2+, NO+ and Kr+ with 10 readily available (at the time of purchase) new psychoactive substances, namely 4-fluoroamphetamine, methiopropamine, ethcathinone, 4-methylethcathinone, N-ethylbuphedrone, ethylphenidate, 5-MeO-DALT, dimethocaine, 5-(2-aminopropyl)benzofuran and nitracaine. In particular, the dependence of product ion branching ratios on the reduced electric field strength for all reagent ions was investigated and is reported here. The results reported represent a significant amount of new data which will be of use for the development of drug detection techniques suitable for real world scenarios.

Label-free SERS-ML detection of cocaine trace in human blood plasma.

The widespread consumption of cocaine poses a significant threat to modern society. The most effective way to combat this problem is to control the distribution of cocaine, based on its accurate and sensitive detection. Here, we proposed the detection of cocaine in human blood plasma using a combination of surface enhanced Raman spectroscopy and machine learning (SERS-ML). To demonstrate the efficacy of our proposed approach, cocaine was added into blood plasma at various concentrations and drop-deposited onto a specially prepared disposable SERS substrate. SERS substrates were created by deposition of metal nanoclusters on electrospun polymer nanofibers. Subsequently, SERS spectra were measured and as could be expected, the manual distinguishing of cocaine from the spectra proved unfeasible, as its signal was masked by the background signal from blood plasma molecules. To overcome this issue, a database of SERS spectra of cocaine in blood plasma was collected and used for ML training and validation. After training, the reliability of proposed approach was tested on independently prepared samples, with unknown for SERS-ML cocaine presence or absence. As a result, the possibility of rapid determination of cocaine in blood plasma with a probability above 99.5% for cocaine concentrations up to 10-14 M was confirmed. Therefore, it is evident that the proposed approach has the ability to detect trace amounts of cocaine in bioliquids in an express and simple manner.

A novel approach to low-cost, rapid and simultaneous colorimetric detection of multiple analytes using 3D printed microfluidic channels.

This research paper presents an inventive technique to swiftly create microfluidic channels on distinct membrane papers, enabling colorimetric drug detection. Using a modified DIY RepRap 3D printer with a syringe pump, microfluidic channels (µPADs) are crafted on a flexible nylon-based substrate. This allows simultaneous detection of four common drugs with a single reagent. An optimized blend of polydimethylsiloxane (PDMS) dissolved in hexane is used to create hydrophobic channels on various filter papers. The PDMS-hexane mixture infiltrates the paper's pores, forming hydrophobic barriers that confine liquids within the channels. These barriers are cured on the printer's hot plate, controlling channel width and preventing spreading. Capillary action drives fluid along these paths without spreading. This novel approach provides a versatile solution for rapid microfluidic channel creation on membrane papers. The DIY RepRap 3D printer integration offers precise control and faster curing. The PDMS-hexane solution accurately forms hydrophobic barriers, containing liquids within desired channels. The resulting microfluidic system holds potential for portable, cost-effective drug detection and various sensing applications.

Development and evaluation of portable NIR technology for the identification and quantification of Australian illicit drugs.

The efficient and accurate analysis of illicit drugs remains a constant challenge in Australia given the high volume of drugs trafficked into and around the country. Portable drug testing technologies facilitate the decentralisation of the forensic laboratory and enable analytical data to be acted upon more efficiently. Near-infrared (NIR) spectroscopy combined with chemometric modelling (machine learning algorithms) has been highlighted as a portable drug testing technology that is rapid and accurate. However, its effectiveness depends upon a database of chemically relevant specimens that are representative of the market. There are chemical differences between drugs in different countries that need to be incorporated into the database to ensure accurate chemometric model prediction. This study aimed to optimise and assess the implementation of NIR spectroscopy combined with machine learning models to rapidly identify and quantify illicit drugs within an Australian context. The MicroNIR (Viavi Solutions Inc.) was used to scan 608 illicit drug specimens seized by the Australian Federal Police comprising of mainly crystalline methamphetamine hydrochloride (HCl), cocaine HCl, and heroin HCl. A number of other traditional drugs, new psychoactive substances and adulterants were also scanned to assess selectivity. The 3673 NIR scans were compared to the identity and quantification values obtained from a reference laboratory in order to assess the proficiency of the chemometric models. The identification of crystalline methamphetamine HCl, cocaine HCl, and heroin HCl specimens was highly accurate, with accuracy rates of 98.4 %, 97.5 %, and 99.2 %, respectively. The sensitivity of these three drugs was more varied with heroin HCl identification being the least sensitive (methamphetamine = 96.6 %, cocaine = 93.5 % and heroin = 91.3 %). For these three drugs, the NIR technology provided accurate quantification, with 99 % of values falling within the relative uncertainty of ±15 %. The MicroNIR with NIRLAB infrastructure has demonstrated to provide accurate results in real-time with clear operational applications. There is potential to improve informed decision-making, safety, efficiency and effectiveness of frontline and proactive policing within Australia.

Hydrogel-Coated SERS Microneedles for Drug Monitoring in Dermal Interstitial Fluid.

In vivo drug monitoring is crucial for evaluating the effectiveness and safety of drug treatment. Blood sampling and analysis is the current gold standard but needs professional skills and cannot meet the requirements of point-of-care testing. Dermal interstitial fluid (ISF) showed great potential to replace blood for in vivo drug monitoring; however, the detection was challenging, and the drug distribution behavior in ISF was still unclear until now. In this study, we proposed surface-enhanced Raman spectroscopy (SERS) microneedles (MNs) for the painless and real-time analysis of drugs in ISF after intravenous injection. Using methylene blue (MB) and mitoxantrone (MTO) as model drugs, the innovative core-satellite structured Au@Ag SERS substrate, hydrogel coating over the MNs, rendered sensitive and quantitative drug detection in ISF of mice within 10 min. Based on this technique, the pharmacokinetics of the two drugs in ISF was investigated and compared with those in blood, where the drugs were analyzed via liquid chromatography-mass spectrometry. It was found that the MB concentration in ISF and blood was comparable, whereas the concentration of MTO in ISF was 2-3 orders of magnitude lower than in blood. This work proposed an efficient tool for ISF drug monitoring. More importantly, it experimentally proved that the penetration ratio of blood to ISF was drug-dependent, providing insightful information into the potential of ISF as a blood alternative for in vivo drug detection.

Ionic Liquid-Based Hybrid Gel Microcolumns for Enhanced Narcotic Detection in Portable Micro-Gas Chromatography.

As the societal issue of increasing global illicit drug usage emerges, there is a growing demand for more portable and versatile drug detectors. Traditional drug analysis techniques such as gas chromatography (GC), liquid chromatography (LC), and Fourier transform infrared spectroscopy (FTIR) face significant challenges in adapting to diverse real-world applications due to their size, cost, and power requirements. While advancements have been made in the development of on-site drug detection methods such as fluorescence, stereoresonance energy transfer (FRET), colorimetric, electrochemical sensing, and lateral flow assays (LFAs), their reliance on specific reactive materials poses limitations in effectively detecting a wide range of narcotics. Therefore, this study proposes the development of specialized microcolumns with optimized stationary phases for next-generation portable microfabricated GC-based narcotic detectors. The stationary phase consists of a hybrid gel incorporating the ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and OV-1. The stationary phase not only enhances interactions between drug analytes but also demonstrates improved separation characteristics among various narcotic substances. Additionally, the principles of the separation results were validated through density functional theory (DFT) analysis, and the effective separation of over seven types of narcotics was demonstrated through temperature optimization. This research lays the groundwork for the advancement of next-generation portable drug analyzers, offering significant potential in the field.