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Hypothesis Due to the intrinsic nature of the surface-enhanced Raman scattering (SERS), the detection of molecules with weak binding affinities toward metal substrates is critical for development of a universal SERS sensing platform. We hypothesized the physical trapping of small pesticide molecules for active hot spot generation using tyramine-mediated crosslinking chemistry and silver nanoparticles (Ag NPs) enhances SERS detection sensitivity. Experiments Tyramine-mediated crosslinking chemistry for sensor application was validated by ultraviolet–visible absorption spectroscopy, scanning electron microscopy, dynamic light scattering, and Raman spectroscopy. SERS sensing platform using tyramine-mediated crosslinking reaction was systematically studied for detection of 1,4-dyethylnylbenzene as a model analyte. This sensor system was applied to detect two other pesticides, thiabendazole and 1,2,3,5-tetrachlorobenzene, which have different binding affinities toward metal surfaces. Findings The SERS signal of 1,4-dyethylnylbenzene obtained using this sensor system was 3.6 times stronger than that obtained using the Ag colloidal due to the nanogap of approximately 1.3 nm within the generated hot spots. This sensor system based on tyramine-mediated crosslinked Ag NPs was evaluated as a promising tool to achieve a solution based sensitive detection of various pesticide molecules that cannot be adsorbed on the surfaces of typical SERS substrates such as metal nanoparticles.

Background Aconitine is well-known for its potential analgesic, anti-inflammatory, and circulation promoting effects and has been widely used as a folk medicine in South Korea. Owing to its extremely toxic nature and relatively low safety margin, intoxication is sometimes fatal. The toxic compound mainly affects the central nervous system, heart, and muscle, resulting in cardiovascular complications. Purpose To determine the exact relationship between blood concentration of aconitine and clinical manifestation. Basic procedures The National Forensic Service (NFS) was commissioned to assist in a quantitative analysis of highly toxic aconitine and corresponding blood concentrations by analyzing the body fluids of three patients who were suspected of aconitine poisoning. Main findings Aconitine blood values tested by the NFS showed that patients with a blood concentration below a certain level developed symptoms slowly and showed a high severity of clinical manifestation. There was no correlation between blood concentration and symptoms or ECG results. Conclusions In case of suspected aconitine poisoning, an emergency care department should be visited, even with symptomatic improvement, and the patient should be monitored for at least 24 h, depending on the level of recovery and changes in ECG results.

The strategy of structure-inherent tumor targeting (SITT) with cyanine-based fluorophores is receiving more attention because no chemical conjugation of targeting moieties is required. However, the targeting mechanism behind SITT has not yet been well explained. Here, it is demonstrated that heptamethine-cyanine-based fluorophores possess not only targetability of tumor microenvironments without the need for additional targeting ligands but also second near-infrared spectral window (NIR-II) imaging capabilities, i.e., minimum scattering and ultralow autofluorescence. The new SITT mechanism suggests that bone-marrow-derived and/or tissue-resident/tumor-associated immune cells can be a principal target for cancer detection due to their abundance in tumoral tissues. Among the tested, SH1 provides ubiquitous tumor targetability and a high tumor-to-background ratio (TBR) ranging from 9.5 to 47 in pancreatic, breast, and lung cancer mouse models upon a single bolus intravenous injection. Furthermore, SH1 can be used to detect small cancerous tissues smaller than 2 mm in diameter in orthotopic lung cancer models. Thus, SH1 could be a promising cancer-targeting agent and have a bright future for intraoperative optical imaging and image-guided cancer surgery.

To study the distance-dependent electromagnetic field effects related to the enhancement and quenching mechanism of surface-enhanced Raman scattering (SERS) or fluorescence, it is essential to precisely control the distance from the surface of the metal nanoparticle (NP) to the target molecule by using a dielectric layer (e.g., SiO2, TiO2, and Al2O3). However, precisely controlling the thickness of this dielectric layer is challenging. Herein, we present a facile approach to control the thickness of the silica shell on silver nanoparticle-assembled silica nanocomposites, SiO2@Ag NPs, by controlling the number of reacting SiO2@Ag NPs and the silica precursor. Uniform silica shells with thicknesses in the range 5–40 nm were successfully fabricated. The proposed method for creating a homogeneous, precise, and fine silica coating on nanocomposites can potentially contribute to a comprehensive understanding of the distance-dependent electromagnetic field effects and optical properties of metal NPs.

Gold nanocubes modified to form roughened structures, namely, gold bumpy nanocubes (Au BNCs), with very strong and uniform single-particle surface-enhanced Raman scattering (SERS) intensity were developed. The Au BNCs were synthesized by controlled regrowth, competing with 4-aminothiophenol during gold nanocube growth. Under controlled conditions, Au BNCs of various sizes were successfully generated while maintaining a cubic outline. As the bumpy surfaces of the Au BNCs increased the number of hot spots on a single cubic nanoparticle, these nanoparticles exhibited 15-times stronger SERS than normal cubic nanoparticles. We expect that this unique nanostructure will be applicable in versatile fields as an ultrasensitive SERS nanoprobe or nanoantenna owing to its cubic outline and high uniformity, as well as the ease of particle size adjustment.

The use of carbon-based nanomaterials (CNs) with outstanding properties has been rising in many scientific and industrial application fields. These CNs represent a tunable alternative for applications with biomolecules, which allow interactions in either covalent or noncovalent way. Diverse carbon-derived nanomaterial family exhibits unique features and has been widely exploited in various biomedical applications, including biosensing, diagnosis, cancer therapy, drug delivery, and tissue engineering. In this chapter, we aim to present an overview of CNs with a particular interest in intrinsic structural, electronic, and chemical properties. In particular, the detailed properties and features of CNs and its derivatives, including carbon nanotube (CNT), graphene, graphene oxide (GO), and reduced GO (rGO) are summarized. The interesting biomedical applications are also reviewed in order to offer an overview of the possible fields for scientific and industrial applications of CNs.

Nanotechnology is a rapidly growing area of development by numerous research groups across the world with its potential applications gaining recognition since the 1950s across various fields. During the last decade of the twentieth century, researchers have actively engaged in the synthesis of nanoparticles and investigation of their physicochemical properties. Advancing the research momentum forward at the beginning of the twenty-first century, rapid development of nanoscience allowed to demonstrate unprecedented advantages of the nanomaterials and its applications in a wide range of fields. The interdisciplinary nature of nanoscience and its expansion has led to establishment of new laboratories and research centers, with increasing needs on training and educating young scientists in advanced laboratory protocols. In addition, pedagogical demands in nanotechnology and nanomaterials have resulted an emergence of new dedicated curriculums at universities which has sped up the development of nanoscience and its contribution to the body of knowledge in natural science.

In this review, we focus on sensing techniques and biological applications of various luminescent nanoparticles including quantum dot (QD), up-conversion nanoparticles (UCNPs) following the previous chapter. Fluorescent phenomena can be regulated or shifted by interaction between biological targets and luminescence probes depending on their distance, which is so-called Fӧrster resonance energy transfer (FRET). QD-based FRET technique, which has been widely applied as a bioanalytical tool, is described. We discuss time-resolved fluorescence (TRF) imaging and flow cytometry technique, using photoluminescent nanoparticles with unique properties for effectively improving selectivity and sensitivity. Based on these techniques, bioanalytical and biomedical application, bioimaging with QD, UCNPs, and Euripium-activated luminescent nanoprobes are covered. Combination of optical property of these luminescent nanoparticles with special functions such as drug delivery, photothermal therapy (PTT), and photodynamic therapy (PDT) is also described.

Nano is a fine metric unit which means "one billionth." Nanotechnology is attracting attention as a technological basis to lead the fourth industry. By utilizing synergistic properties obtained from controlling the structure or arrangement of materials at the nanoscale, nanotechnology has evolved rapidly over the past half century and is active in a variety of fields such as materials, pharmaceuticals, and biology. This chapter briefly describes the concept and features of nanotechnology, as well as the preparation, analysis, characterization, and application of nanomaterials. Also, the prospects for nanotechnology along with the nanotoxicity are described.

Following the previous chapter, recent synthetic methods of metal-based nanoparticles and their applications based on plasmonic resonance properties are described in this chapter. This differs from the previous chapter, which described the general uses of metal-based nanoparticles, in that various recent advanced applications of metal-based nanoparticles are described in this chapter.

Near-infrared (NIR) fluorescence imaging has advanced medical imaging and image-guided interventions during the past three decades. Despite tremendous advances in imaging devices, surprisingly only a few dyes are currently available in the clinic. Previous fluorophores, ZW800-1A and ZW800-1C, significantly improved the poor performance of the FDA-approved indocyanine green. However, ZW800-1A is not stable in serum and ZW800-1C induces severe stacking in aqueous media. To solve such dilemmas, ZW800-PEG was designed by introducing a flexible yet stable thiol PEG linker. ZW800-PEG shows high solubility in both aqueous and organic solvents, thus improving renal clearance with minimal binding to serum proteins during systemic circulation. The sulfide group on the meso position of the heptamethine core improves serum stability and physicochemical properties including the maximum emission wavelength shift to 800 nm, enabling the use of ZW800-PEG for image-guided interventions and augmenting photothermal therapy.

It is almost impossible to fabricate size-controlled nanomaterials without full understanding about nanoscience, because nanomaterials sometimes suddenly grow up and precipitated, meanwhile other nanomaterials are disappeared during fabrication process. With this reason, it is necessary to understand the principle theories about nanoscience for fabrication of "well-defined" nanoparticles. This chapter explains basic theories about nanomaterials. And based on the theory, methods for controlling the size of nanoparticles and preventing the aggregation after fabrication are described.

Silica consists of one silicon atom and two oxygen atoms (SiO

This review presents the main characteristics of metal nanoparticles (NPs), especially consisting of noble metal such as Au and Ag, and brief information on their synthesis methods. The physical and chemical properties of the metal NPs are described, with a particular focus on the optically variable properties (surface plasmon resonance based properties) and surface-enhanced Raman scattering of plasmonic materials. In addition, this chapter covers ways to achieve advances by utilizing their properties in the biological studies and medical fields (such as imaging, diagnostics, and therapeutics). These descriptions will help researchers new to nanomaterials for biomedical diagnosis to understand easily the related knowledge and also will help researchers involved in the biomedical field to learn about the latest research trends.

Not only is fabrication important for research in materials science, but also materials characterization and analysis. Special microscopes capable of ultra-high magnification are more essential for observing and analyzing nanoparticles than for macro-size particles. Recently, electron microscopy (EM) and scanning probe microscopy (SPM) are commonly used for observing and analyzing nanoparticles. In this chapter, the basic principles of various techniques in optical and electron microscopy are described and classified. In particular, techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are explained.

Magnetic nanoparticles have been used in various fields such as data storage, biomedicine, or bioimaging with their unique magnetic property. With their low toxicity, the importance of magnetic nanoparticles keeps increasing especially in biological field. In this chapter, content suitable for scientific inquirers or undergraduates to acquire basic knowledge about nanotechnology is introduced and then recent research trends in nanotechnology are covered.

We present a template-assisted method for synthesizing nanogap shell structures for biomolecular detections based on surface-enhanced Raman scattering. The interior nanogap-containing a silver shell structure, referred to as a silver nanogap shell (Ag NGS), was fabricated on silver nanoparticles (Ag NPs)-coated silica, by adsorbing small aromatic thiol molecules on the Ag NPs. The Ag NGSs showed a high enhancement factor and good signal uniformity, using 785-nm excitation. We performed in vitro immunoassays using a prostate-specific antigen as a model cancer biomarker with a detection limit of 2 pg/mL. To demonstrate the versatility of Ag NGS nanoprobes, extracellular duplex surface-enhanced Raman scattering (SERS) imaging was also performed to evaluate the co-expression of cancer biomarkers, human epidermal growth factor-2 (HER2) and epidermal growth factor receptor (EGFR), in a non-small cell lung cancer cell line (H522). Developing highly sensitive Ag NGS nanoprobes that enable multiplex biomolecular detection and imaging can open up new possibilities for point-of-care diagnostics and provide appropriate treatment options and prognosis.

In this review, we focus on sensing techniques and biological applications of various luminescent nanoparticles including quantum dot (QD), up-conversion nanoparticles (UCNPs) following the previous chapter. Fluorescent phenomena can be regulated or shifted by interaction between biological targets and luminescence probes depending on their distance, which is so-called Fӧrster resonance energy transfer (FRET). QD-based FRET technique, which has been widely applied as a bioanalytical tool, is described. We discuss time-resolved fluorescence (TRF) imaging and flow cytometry technique, using photoluminescent nanoparticles with unique properties for effectively improving selectivity and sensitivity. Based on these techniques, bioanalytical and biomedical application, bioimaging with QD, UCNPs, and Euripium-activated luminescent nanoprobes are covered. Combination of optical property of these luminescent nanoparticles with special functions such as drug delivery, photothermal therapy (PTT), and photodynamic therapy (PDT) is also described.

It is almost impossible to fabricate size-controlled nanomaterials without full understanding about nanoscience, because nanomaterials sometimes suddenly grow up and precipitated, meanwhile other nanomaterials are disappeared during fabrication process. With this reason, it is necessary to understand the principle theories about nanoscience for fabrication of "well-defined" nanoparticles. This chapter explains basic theories about nanomaterials. And based on the theory, methods for controlling the size of nanoparticles and preventing the aggregation after fabrication are described.

This review presents the main characteristics of metal nanoparticles (NPs), especially consisting of noble metal such as Au and Ag, and brief information on their synthesis methods. The physical and chemical properties of the metal NPs are described, with a particular focus on the optically variable properties (surface plasmon resonance based properties) and surface-enhanced Raman scattering of plasmonic materials. In addition, this chapter covers ways to achieve advances by utilizing their properties in the biological studies and medical fields (such as imaging, diagnostics, and therapeutics). These descriptions will help researchers new to nanomaterials for biomedical diagnosis to understand easily the related knowledge and also will help researchers involved in the biomedical field to learn about the latest research trends.

Nanobiotechnology is known as the application of nanoscaled techniques in biology which bridges natural science to living organism for improving the quality of life of humans. Nanotechnology was first issued in 1959 and has been rapidly developed, supplying numerous benefits to basic scientific academy and to clinical application including human healthcare, specifically in cancer therapy. This chapter discusses recent advances and potentials of nanotechnology in pharmaceutics, therapeutics, biosensing, bioimaging, and gene delivery that demonstrate the multifunctionality of nanotechnology.

Nanotechnology is a rapidly growing area of development by numerous research groups across the world with its potential applications gaining recognition since the 1950s across various fields. During the last decade of the twentieth century, researchers have actively engaged in the synthesis of nanoparticles and investigation of their physicochemical properties. Advancing the research momentum forward at the beginning of the twenty-first century, rapid development of nanoscience allowed to demonstrate unprecedented advantages of the nanomaterials and its applications in a wide range of fields. The interdisciplinary nature of nanoscience and its expansion has led to establishment of new laboratories and research centers, with increasing needs on training and educating young scientists in advanced laboratory protocols. In addition, pedagogical demands in nanotechnology and nanomaterials have resulted an emergence of new dedicated curriculums at universities which has sped up the development of nanoscience and its contribution to the body of knowledge in natural science.

Nano is a fine metric unit which means "one billionth." Nanotechnology is attracting attention as a technological basis to lead the fourth industry. By utilizing synergistic properties obtained from controlling the structure or arrangement of materials at the nanoscale, nanotechnology has evolved rapidly over the past half century and is active in a variety of fields such as materials, pharmaceuticals, and biology. This chapter briefly describes the concept and features of nanotechnology, as well as the preparation, analysis, characterization, and application of nanomaterials. Also, the prospects for nanotechnology along with the nanotoxicity are described.

The use of carbon-based nanomaterials (CNs) with outstanding properties has been rising in many scientific and industrial application fields. These CNs represent a tunable alternative for applications with biomolecules, which allow interactions in either covalent or noncovalent way. Diverse carbon-derived nanomaterial family exhibits unique features and has been widely exploited in various biomedical applications, including biosensing, diagnosis, cancer therapy, drug delivery, and tissue engineering. In this chapter, we aim to present an overview of CNs with a particular interest in intrinsic structural, electronic, and chemical properties. In particular, the detailed properties and features of CNs and its derivatives, including carbon nanotube (CNT), graphene, graphene oxide (GO), and reduced GO (rGO) are summarized. The interesting biomedical applications are also reviewed in order to offer an overview of the possible fields for scientific and industrial applications of CNs.

Following the previous chapter, recent synthetic methods of metal-based nanoparticles and their applications based on plasmonic resonance properties are described in this chapter. This differs from the previous chapter, which described the general uses of metal-based nanoparticles, in that various recent advanced applications of metal-based nanoparticles are described in this chapter.

Not only is fabrication important for research in materials science, but also materials characterization and analysis. Special microscopes capable of ultra-high magnification are more essential for observing and analyzing nanoparticles than for macro-size particles. Recently, electron microscopy (EM) and scanning probe microscopy (SPM) are commonly used for observing and analyzing nanoparticles. In this chapter, the basic principles of various techniques in optical and electron microscopy are described and classified. In particular, techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are explained.

Background: QT prolongation is a well-known complication when tramadol or zolpidem is ingested in large amounts acutely. However, the blood drug concentration resulting in QT prolongation or tachyarrhythmia when tramadol and zolpidem are ingested simultaneously in large amounts has not yet been reported. We report a case of acute intoxication by tramadol and zolpidem resulting in QT prolongation in a patient in whomserial blood and urine tramadol and zolpidemconcentrationswere determined.Case presentation:A 38-year-old male patient presented tothe emergency medical centrebecause ofpoisoning from 3 g of tramadol and 50 mg of zolpidemat 3 h before hisemergency department(ED) visit.During supportive treatment, he developed QT prolongation without clinical manifestations. He was discharged five days after admission without any sequelae. We measured the blood and urine concentrations of tramadol and zolpidemat various time points, which revealed ablood tramadol concentration-dependent change in QTc intervals and increasing blood tramadol concentration at 8 h after the ED visit,with a sustainedlow zolpidem concentration.Tramadol and zolpidem are metabolized by the same enzyme, cytochrome P450 3A4.Therefore, competitive inhibition bya P450 3A4isoenzyme may lead to increases indrugtoxicity. The QT interval in patients acutely intoxicated bytramadol should be evaluated carefully, particularlywhen tramadol is co-ingested with other drugs.Conclusions:Considering the half-life of tramadolor zolpidem and potential for continued absorption of drugs remaining in the gastrointestinal tract, it is necessary to observe patients viacardiac monitoring for more than 36 hafteracute intoxication.The blood concentration of tramadol may increaseand result in QT prolongationeven afterappropriate initial treatment.

Noble metal structures with interior sub-nanometer gaps are highly promising as ultra-sensitive surface-enhanced Raman scattering (SERS) nanoprobes for generating uniform and reproducible hot spots in nanogaps. However, existing methods for synthesizing interior nanogap structures are challenged by difficulties in controlling the positions of Raman label compounds in the nanogaps and in functionalizing the tethering molecules. Herein, we present a template-assisted method for synthesizing nanogap shell structures for biomolecular detections. The interior nanogap-containing silver shell structure, referred to as a silver nanogap shell (Ag NGS), was fabricated on silver nanoparticles (Ag NPs)-coated silica, by adsorbing small aromatic thiol molecules on the Ag NPs. The Ag NGSs showed a high enhancement factor and good signal uniformity, using 785-nm excitation. We performed in vitro immunoassays using a prostate-specific antigen as a model cancer biomarker with a detection limit of 2 pg/mL. To demonstrate the versatility of Ag NGS nanoprobes, extracellular duplex SERS imaging was also performed to evaluate the co-expression of cancer biomarkers, HER2 and EGFR, in a non-small cell lung cancer cell line (H522). Developing highly sensitive Ag NGS nanoprobes enabling multiplex biomolecular detection and imaging can open up new possibilities for point-of-care diagnostics and provide appropriate treatment options and prognosis.

In Korea, an increasing number of people attempt to evade military conscription by posing as mental health patients. To verify the authenticity of mental illness, there is a need to detect wide range of psychoactive agents in biological specimens of conscription candidates. In this study, we developed and validated a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for simultaneous determination of 18 psychoactive agents and 6 metabolites in human plasma. The method was characterized by the use of a simple, fast and cheap protein precipitation as sample preparation, a rapid run time (11 min) and a low volume of plasma sample (200 μL). The analytes were monitored under the scheduled multiple reaction monitoring (sMRM) positive and negative mode using electrospray ionization (ESI). The essential validation parameters including selectivity, linearity, accuracy, precision, matrix effect and recovery were satisfactory. The limit of detection ranged from 0.0005 to 0.001 μg/mL, and limit of quantitation ranged from 0.005 to 0.025 μg/mL. The developed method was successfully applied to 323 actual plasma samples submitted by Korea central physical examination center of military manpower administration in 2016, and is expected to contribute to the rapid and accurate disposition of military service.

The surface-enhanced Raman scattering (SERS) technique, that uses magnetic plasmonic particles (MPPs), is an advanced SERS detection platform owing to the synergetic effects of the particles’ magnetic and plasmonic properties. As well as being an ultrasensitive and reliable SERS material, MPPs perform various functions, such as aiding in separation, drug delivery, and acting as a therapeutic material. This literature discusses the structure and multifunctionality of MPPs, which has enabled the novel application of MPPs to various biological fields.

Bacteriophages are thought to be ideal vehicles for linking antibodies to nanoparticles. Here, we define the sequence of peptides exposed as a fusion protein on M13 bacteriophages to yield optimal binding of gold nanocubes and efficient bacteriophage amplification. We generated five helper bacteriophage libraries using AE(X)2DP, AE(X)3DP, AE(X)4DP, AE(X)5DP, and AE(X)6DP as the exposed portion of pVIII, in which X was a randomized amino acid residue encoded by the nucleotide sequence NNK. Efficient phage amplification was achievable only in the AE(X)2DP, AE(X)3DP, and AE(X)4DP libraries. Through biopanning with gold nanocubes, we enriched the phage clones and selected the clone with the highest fold change after enrichment. This clone displayed Pro–Asp on the surface of the bacteriophage and had amplification yields similar to those of the wild-type helper bacteriophage (VCSM13). The clone displayed even binding of gold nanocubes along its length and minimal aggregation after binding. We conclude that, fo...

Antibody-conjugated nanoparticles (NPs) have attracted great attention in diagnostic and therapeutic applications due to their high sensitivity and specificity for biotargets, as well as their wide applicability. Unfortunately, these features are significantly affected by antibody conjugation methods in terms of conjugation efficiency, orientation of the target binding site in the antibody, and denaturation during chemical conjugation reactions. Furthermore, the number of conjugated antibodies on each NP and the overall targeting efficacy are critical factors for a quantitative bioassay with antibody-conjugated NPs. Herein, we report a versatile and oriented antibody conjugation method using copper-free click chemistry. Moreover, the number of conjugated antibodies and their binding capacity were quantitatively and experimentally evaluated using fluorescently-labeled antibodies and antigens. The strong binding capability of antibody-conjugated NPs prepared using the copper-free click chemistry-based conjugation strategy was 8 times superior to the binding capability seen following the use of the EDC/NHS-coupling method. Additionally, the versatility of the developed antibody conjugation method was also demonstrated by conjugation of the antibody to three kinds of silica-encapsulated NPs.

The fabrication of hollow metal nanostructures on a silica core template has been widely studied by taking advantage of the chemical stabilities of silica cores. When the size of the silica core reduces, however, this benefit is no longer effective because there are the synthetic difficulties which often cause dispersion instability, and therefore finally the aggregations of nanoparticles (NPs) are often caused during introduction of metallic nanostructures. This study reports the successful fabrication of silver nanoshells (AgNSs; 119, 152, 165, 186, and 207 nm) on amorphous silica nanoparticles (Si NPs) of different core sizes (59, 82, 103, 124, and 148 nm) by overcoming the increased instabilities during fabrication with reduced core sizes. Improvements related to fabrication were made by changing the reducing agents, controlling the amount of the dispersing agent and the concentration of Si NPs. All the AgNSs showed broad extinction from the visible to the near-infrared (NIR) region regardless of particle sizes, and their size-dependent surface properties were analyzed by introducing a concept of roughness factor, with AgNS of 152 nm exhibiting the highest degree of roughness. High SERS enhancements of AgNSs of all sizes were observed at three laser excitation wavelengths (532, 660, and 785 nm), and these enhancements correlated positively with the surface roughness. Therefore, our results provide a clear understanding of size-dependent SERS activity for AgNS, facilitating proper selection of AgNS with an appropriate size depending on the purpose of the investigation.

The morphological variation of stimuli-responsive polypeptide molecules at the air–water interface as a function of temperature and compression was described. The surface pressure–area (π–A) isotherms of an elastin-like polypeptide (ELP) monolayer were obtained under variable external conditions, and Langmuir–Blodgett (LB) monolayers were deposited onto a mica substrate for characterization. As the compression of the ELP monolayer increased, the surface pressure increased gradually, indicating that the ELP monolayer could be prepared with high stability at the air–water interface. The temperature in the subphase of the ELP monolayer was critical in the preparation of LB monolayers. The change in temperature induced a shift in the π–A isotherms as well as a change in ELP secondary structures. Surprisingly, the compression of the ELP monolayer influenced the ELP secondary structure due to the reduction in the phase transition temperature with decreasing temperature. The change in the ELP secondary structure formed at the air–water interface was investigated by surface-enhanced Raman scattering. Moreover, the morphology of the ELP monolayer was subsequently imaged using atomic force microscopy. The temperature responsive behavior resulted in changes in surface morphology from relatively flat structures to rugged labyrinth structures, which suggested conformational changes in the ELP monolayers.

Dear editor,Certain shellfish commonly ingested by humans contain toxins and can cause systemic poisoning [1]. Although a few cases of tetramethylammonium (TMA) poisoning due to Neptunea ingestion ...

Recently, surface-enhanced Raman scattering (SERS)-based immunoassays (SIA) have drawn much attention as diagnostic tools with large multiplex capacity and high sensitivity. However, several challenges—such as a low reproducibility, a time-consuming read-out process, and limited dynamic range—remain. In this study, we report a reliable and sensitive SIA platform for prostate specific antigen (PSA) detection. Reliability and sensitivity were achieved by two approaches: (1) well-established SERS probes, so-called SERS dots that have high sensitivity (single particle detection) and little particle-to-particle variation in SERS intensity; and (2) a whole area-scanning readout method for rapid and reliable chip analysis rather than point scanning. As a feasibility test, PSA could be detected with high sensitivity (ca. 0.11 pg/mL, 3.4 fM LOD), with a wide dynamic range (0.001–1000 ng/mL). Thus, the developed platform will facilitate development of reliable immunoassays with high sensitivity and a wide dynamic r...

Phenylalkylamine derivatives, such as methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), phentermine, fenfluramine, phendimetrazine, amfepramone, and ketamine, are widely abused recreational or anorectic drugs in Korea, and their abuse has become a serious social problem. Hair is a useful specimen to prove chronic use and liquid chromatography-tandem mass spectrometry (LC-MS/MS) has recently become a more popular tool for hair analysis due to sensitivity and simplicity in sample preparation. In order to overcome limitations of standard reversed-phase column to separate low molecular weight amines, we adopted a multi-mode reversed-phase column, Scherzo SS-C18, which was composed of strong ionic ligands and C18 ligands, and used pH gradient elution to separate seven psychotropic phenylalkylamines and their metabolites. The essential validation parameters including selectivity, LOD, LLOQ, linearity, intra- and inter-assay precision and accuracy, recovery, and the matrix effect were satisfactory. The LODs ranged from 0.1 ng/5 mg hair (diethylnorephedrine, fenfluramine, ketamine, and MA) to 0.5 ng/5 mg hair (amfepramone, MDA, phendimetrazine, and phentermine). The LLOQs were 1 ng/5 mg hair for all analytes. The developed method was successfully applied to determination of phenylalkylamines in authentic hair samples analyzed previously by a routine gas chromatography/mass spectrometry (GC–MS) method. A good correlation was observed between the two methods, with a slope near one.

Metallic alloy nanoparticles are synthesized by combining two or more different metals. Bimetallic or trimetallic nanoparticles are considered more effective than monometallic nanoparticles because of their synergistic characteristics. In this review, we outline the structure, synthesis method, properties, and biological applications of metallic alloy nanoparticles based on their plasmonic, catalytic, and magnetic characteristics.

‘Split-and-mix’ synthetic methods are widely utilized to prepare extensively large numbers of combinatorial libraries. For this, a simple and reliable encoding/decoding method is required to identify a lead compound, especially when it comes to combinatorial peptide/peptoid libraries. Here, we report a simple, efficient, and reliable on-bead peptoid ligand identification method using dual-modal identifiers (DM-IDs), which have a graphical pattern and a Raman signal. The DM-ID was designed to encode the sequence and the type of peptoid side chain by the number of holes and the surface-enhanced Raman scattering (SERS) signals, respectively. Using this dual encoding strategy, 5832 (183)-individual peptides/peptoids can be encoded with 3 holes and 18 Raman label compounds. In addition, the method can be easily extended to encode more than one hundred billion ligands by expanding to 9 patterns with 3 holes in binary code. After pentapeptoids were encoded with DM-IDs during solid phase synthesis, the peptoid’s affinity towards streptavidin is successfully evaluated, and the on-bead peptoid sequence is determined by the graphical patterns and the SERS signatures of the DM-IDs. We believe that this encoding method using DM-IDs is a promising tool to construct one-bead-one-compound (OBOC) combinatorial libraries for drug discovery.