SERS-Based Biosensors Combined with Machine Learning for Medical Application.

Surface-enhanced Raman spectroscopy (SERS) has shown strength in non-invasive, rapid, trace analysis and has been used in many fields in medicine. Machine learning (ML) is an algorithm that can imitate human learning styles and structure existing content with the knowledge to effectively improve learning efficiency. Integrating SERS and ML can have a promising future in the medical field. In this review, we summarize the applications of SERS combined with ML in recent years, such as the recognition of biological molecules, rapid diagnosis of diseases, developing of new immunoassay techniques, and enhancing SERS capabilities in semi-quantitative measurements. Ultimately, the possible opportunities and challenges of combining SERS with ML are addressed.

Simultaneous determination of diquat and its two primary metabolites in rat plasma by ultraperformance liquid chromatography-tandem mass spectrometry and its application to the toxicokinetic study.

PURPOSE: This study aimed to develop and validate an ultraperformance liquid chromatography-tandem mass spectrometry to simultaneously determine diquat (DQ) and its two primary metabolites in rat plasma and its application to the toxicokinetic study. METHOD: The chromatographic separation of DQ and its two primary metabolites was performed with hydrophilic interaction chromatography column by adding formic acid and ammonium acetate in mobile phase in stepwise elution mode. DQ and its two primary metabolites were detected by liquid chromatography-tandem mass spectrometry in positive mode. RESULTS: The lower limit of quantification ranging from 0.3 to 3.0 ng/mL for DQ and its two primary metabolites was achieved by using only 50 µL of rat plasma. The maximum concentration (Cmax) was 977 ng/mL, half-life (t1/2) was 13.1 h, and area under the plasma concentration-time curve (AUC0-t) was 2770 h*ng/mL for DQ, Cmax was 47.1 ng/mL, t1/2 was 25.1 h, and AUC0-t was 180 h·ng/mL for diquat monopyridone (DQ-M) and Cmax was 246 ng/mL, t1/2 was 8.2 h, and AUC0-t was 2430 h·ng/mL for diquat dipyridone (DQ-D), respectively. CONCLUSIONS: The validated method was shown to be suitable for simultaneous determination of diquat and its two primary metabolites in rat plasma. This study is the first to study the toxicokinetics of DQ and its two primary metabolites.

Development and validation of a sensitive and high throughput UPLC-MS/MS method for determination of paraquat and diquat in human plasma and urine: application to poisoning cases at emergency departments of hospitals.

PURPOSE: Paraquat and diquat are well-known toxic herbicides, at least responsible for hundreds of fatal poisoning events worldwide. However, the determination of diquat and paraquat in plasma and urine is very challenging because of their high polarity and double charge characteristics. In this study, we aim to develop a rapid and reliable method for the determination of paraquat and diquat in human plasma and urine by ultraperformance liquid chromatography-tandem mass spectrometry. METHOD: The chromatographic separation of paraquat and diquat was tested with different chromatographic columns and different mobile phase conditions. The mass parameters were optimized by product ions, source gas flow, cone flow, desolvation temperature, and capillary voltage. The isocratic elution mode gave rapid appearance of peak of paraquat and diquat. RESULTS: The sharp peak shapes for paraquat and diquat were achieved with CORTECS® UPLC® HILIC (100 × 2.1 mm, 1.6 µm) column by adding formic acid and ammonium acetate in mobile phase in isocratic elution mode. The lower limit of quantification of 1.0 ng/mL for paraquat and diquat were achieved using only 50 µL of human plasma or urine. The running time for analysis of both paraquat and diquat was as short as 3.5 min per sample. CONCLUSIONS: A rapid and reliable method for the determination of paraquat and diquat was developed and applied to 387 clinical poisoning cases and 22 poisoning cases were found to be paraquat or diquat poisoning.

Rapid detection of α-amanitin and ß-amanitin in rat plasma by ultra-performance liquid chromatography-tandem mass spectrometry and its application to the toxicokinetic study of Lepiota brunneoincarnata.

PURPOSE: Lepiota brunneoincarnata is a well-known poisonous mushroom and is responsible for fatal mushroom poisoning cases worldwide. α-Amanitin and ß-amanitin are the main amatoxin compounds of Lepiota brunneoincarnata. However, there are no published toxicokinetic studies of Lepiota brunneoincarnata. To study the toxicokinetics of Lepiota brunneoincarnata, we developed an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of α-amanitin and ß-amanitin in rat plasma. METHODS: UPLC-MS/MS analyses were performed with a triple quadrupole mass spectrometer in positive-ion mode. The sensitivity of α-amanitin and ß-amanitin detection was increased by inhibiting the production of [M + Na]+ adducts. α-Amanitin and ß-amanitin were separated and quantified on an UPLC octadecyl silyl column in only 2.5 min. RESULTS: The linear ranges were 3.0-3000 ng/mL for α-amanitin and 1.8-1800 ng/mL for ß-amanitin with a correlation coefficient r > 0.99 for both analytes. The lower limit of quantification of 3.0 ng/mL for α-amanitin and 1.8 ng/mL for ß-amanitin was achieved using only 50 µL of rat plasma. The accuracy of α-amanitin and ß-amanitin was between - 9.5 and 7.0% with the precision ranged from 2.2 to 12.5%. The developed method was then applied for Lepiota brunneoincarnata toxicokinetic study after intravenous administration of Lepiota brunneoincarnata extracts. CONCLUSIONS: Establishing UPLC-MS/MS method for quantifying amanitines in rat plasma successfully enabled toxicokinetic study of Lepiota brunneoincarnata extracts.

Predicting the structure of unexplored novel fentanyl analogues by deep learning model.

Fentanyl and its analogues are psychoactive substances and the concern of fentanyl abuse has been existed in decades. Because the structure of fentanyl is easy to be modified, criminals may synthesize new fentanyl analogues to avoid supervision. The drug supervision is based on the structure matching to the database and too few kinds of fentanyl analogues are included in the database, so it is necessary to find out more potential fentanyl analogues and expand the sample space of fentanyl analogues. In this study, we introduced two deep generative models (SeqGAN and MolGPT) to generate potential fentanyl analogues, and a total of 11 041 valid molecules were obtained. The results showed that not only can we generate molecules with similar property distribution of original data, but the generated molecules also contain potential fentanyl analogues that are not pretty similar to any of original data. Ten molecules based on the rules of fentanyl analogues were selected for NMR, MS and IR validation. The results indicated that these molecules are all unreported fentanyl analogues. Furthermore, this study is the first to apply the deep learning to the generation of fentanyl analogues, greatly expands the exploring space of fentanyl analogues and provides help for the supervision of fentanyl.

In Situ Identification of Unknown Crystals in Acute Kidney Injury Using Raman Spectroscopy.

Raman spectroscopy is a well-established and powerful tool for in situ biomolecular evaluation. Type 2 crystal nephropathies are characterized by the deposition of crystalline materials in the tubular lumen, resulting in rapid onset of acute kidney injury without specific symptoms. Timely crystal identification is essential for its diagnosis, mechanism exploration and therapy, but remains challenging. This study aims to develop a Raman spectroscopy-based method to assist pathological diagnosis of type 2 crystal nephropathies. Unknown crystals in renal tissue slides from a victim suffered extensive burn injury were detected by Raman spectroscopy, and the inclusion of crystals was determined by comparing Raman data with established database. Multiple crystals were scanned to verify the reproducibility of crystal in situ. Raman data of 20 random crystals were obtained, and the distribution and uniformity of substances in crystals were investigated by Raman imaging. A mouse model was established to mimic the crystal nephropathy to verify the availability of Raman spectroscopy in frozen biopsy. All crystals on the human slides were identified to be calcium oxalate dihydrate, and the distribution and content of calcium oxalate dihydrate on a single crystal were uneven. Raman spectroscopy was further validated to be available in identification of calcium oxalate dihydrate crystals in the biopsy specimens. Here, a Raman spectroscopy-based method for in situ identification of unknown crystals in both paraffin-embedded tissues and biopsy specimens was established, providing an effective and promising method to analyze unknown crystals in tissues and assist the precise pathological diagnosis in both clinical and forensic medicine.

Development of a simple and reliable method for α-amanitin detection in rat plasma and its application to a toxicokinetic study.

RATIONALE: α-Amanitin is a highly toxic peptide widely found in species of poisonous mushrooms. The matrix effect has been a major obstacle for accurate determination of α-amanitin in plasma samples by liquid chromatography/tandem mass spectrometry (LC/MS/MS). In this study, the strategy to eliminate the matrix effect of α-amanitin with a one-step dilution approach after deproteinization was applied. METHODS: Rat plasma samples were processed by protein precipitation with methanol followed by a nine-fold dilution with pure water. The matrix effect value of α-amanitin was 19.7%-22.2% by protein precipitation and then changed to 87.5%-88.7% after dilution. α-Amanitin and the internal standard (roxithromycin) were analyzed on an ACQUITY UPLC® BEH C18 (50 mm × 2.1 mm, 1.7 µm) column within 3.0 min by gradient elution. RESULTS: The linear ranges were 0.90-600 ng/mL with a correlation coefficient r >0.9958. A lower limit of quantification (LLOQ) of 0.90 ng/mL was achieved using only 50 µL of rat plasma. The intra- and inter-day precisions for the analyte ranged from 3.2% to 7.5% and 3.1% to 7.1%, respectively, and the accuracy ranged from -5.3% to -8.0%. CONCLUSIONS: The matrix effect of α-amanitin was reduced by sample dilution after plasma deproteinization. A reliable LC/MS/MS method for the determination of α-amanitin in rat plasma was developed. This method was successfully applied for a toxicokinetic study of rats after intravenous injection of α-amanitin with a subacute toxicity dose at 0.10 mg/kg.

Crown monitoring: Trace the dynamic changes of caspase-3 and H2O2 in real-time imaging based on FRET/SERS.

Caspase-3 and hydrogen peroxide (H2O2) are closely associated with numerous diseases, both of them are vital in different physiological and pathological conditions. They are closely related and also can act independently. The selective and accurate determination of caspase-3 and H2O2 simultaneously to determine their state of being in different situations is of great significance for further study of their molecular mechanisms and the elucidation of their biological functions. In our latest research, a AuNPL-crown nanoprobe was obtained by attaching (4-aminosulfonylphenyl) boronic acid (4-APBA) and peptide-FITC (NH2-Asp-Glu-Val-Asp (DEVD)-FITC) to gold nanoplates (AuNPLs). The fabricated AuNPL-crown nanoprobe was used for dual-channel and real-time tracking of the dynamic changes in caspase-3 and H2O2 based on fluorescence resonance energy transfer (FRET)/surface-enhanced Raman spectroscopy (SERS) technology. The AuNPL-crown nanoprobe not only provides synergy but can also achieve noninterference, making the results more reliable and repeatable. This study simultaneously traced the dynamic changes of caspase-3 and H2O2 on a single probe, which provides a potential new platform for the analysis of caspase-3 and H2O2 in the biological environment with high accuracy, sensitivity, convenience, and efficiency. In summary, we develop a new strategy for the simultaneous detection of different substances on a single probe.

Detection of cell-surface sialic acids and photodynamic eradication of cancer cells using dye-modified polydopamine-coated gold nanobipyramids.

A nanoprobe based on polydopamine-coated gold nanobipyramids surface modified with molecules of a phenylboronic acid-substituted distyryl boron dipyrromethene has been fabricated and characterised using various physical and spectroscopic methods. It serves as an ultrasensitive sensor for sialic acids on the surface of cancer cells based on its dual surface-enhanced Raman scattering and fluorescence response. This biomarker can also trigger the photodynamic activity of these nanobipyramids, effectively eradicating the cancer cells mainly through apoptosis as shown by various bioassays.

A green electrolysis of silver-decorated MoS2 nanocomposite with an enhanced antibacterial effect and low cytotoxicity.

To tackle the devastating microbial infections for the public health, a continuous search for effective and safe nanobiocides based on their prominent nanoscale effects has been extensively explored during past decades. In this study, a green electrolysis method was employed to synthesize silver-doped molybdenum sulfide (Ag@MoS2) composite materials. The obtained nanocomposites exhibited a sheet-like structure with a large specific surface area, which contributed to the efficient loading and refined distribution of silver nanoparticles. G- E. coli and G + S. aureus were used as model bacteria for the antibacterial test, which revealed enhanced antibacterial activity of produced nanocomposites with an identified destructive effect on preformed biofilms. It was found that within 72 hour incubation, 20 µg mL-1 Ag@MoS2 was sufficient to inhibit the growth of E. coli and S. aureus without visible colony formation, pointing to a desirable long-term antibacterial activity. Further a mechanistic antibiosis study of Ag@MoS2 indicated the involvement of a generation of reactive oxygen species. Notably, owing to the well-distributed silver nanoparticles on the nontoxic MoS2 nanosheet, the cytotoxicity evaluation results revealed that produced nanocomposites exhibited negligible toxicity to mammalian cells, and thereby held promising potential for biomedical applications.

A Gold Nanoparticle Bouquet held on plasma membrane: An ultrasensitive dark-field imaging approach for Cancer Cell Analysis.

Rational: p53 is suppressing tumor protein correlated with the cell cycle factors and apoptosis. Here, a gold nanoparticle bouquet is designed for an ultrasensitive dark-field imaging approach for cancer cell analysis. Methods: AuNP60/APBA is functionalized by a gold nanoparticle bouquet-plasmonic 60 nm gold nanoparticles. And consistent APBA can be held on the plasma membrane. After 13 nm gold nanoparticles are functionalized with mannose (AuNP13/MN), the AuNP60/APBA gold nanoparticles are captured. The absorption spectrum of aggregation gold nanoparticles (AuNPs) shifts to near-infrared (NIR) region which can be observed under dark-field microscopy (DFM) and is treated the subsequent with photothermal therapy. Results: The results that MCF-7 cells were successfully destroyed under the near-infrared (NIR) irradiation and the intracellular WTp53 increased while the MTp53 decreased. These results indicated that p53 is the key molecule in the apoptosis signaling pathway. Photothermal therapy can stimulate the MTp53 in the cell signal conductive pathway. Conclusion: This work offers a new method for intracellular p53 analysis and a potential targeted cancer treatment.