Resonance Light Scattering Intensity Research Articles

Probing the interaction behavior of Nano-Resveratrol with α-lactalbumin in the presence of β-lactoglobulin and β-casein: spectroscopy and molecular simulation studies

The main purpose of this research was to evaluate the role of α-lactalbumin (α-LA), β-lactoglobulin (β-LG), and β-Caseins (β-CN) in the binding interaction between Nano Resveratrol (Nano Res), as binary and ternary systems. This investigation was fulfilled through the application of multi-spectroscopic, transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM), conductometry, isothermal titration calorimetry (ITC), and molecular dynamics (MD) simulation techniques. Fluorescence spectroscopy observations illustrated the effectiveness of Nano Res throughout the quenching of α-LA, (α-LA-β-LG), and (α-LA-β-CN) complexes, confirming the occurrence of interaction through the combination of static and dynamic mechanisms. An enhancement in the temperature of all three complexes caused a decrease in their Ksv and Kb values, which indicates the static and dynamic behavior of their interactions. The obtained thermodynamic parameters proved the dominance of electrostatic interaction as the binding force of both binary and ternary systems. The observed properties of Tyr or Trp residues in proteins through the data of synchronous spectroscopy at Δλ = 15 and 60 nm, respectively, demonstrated the closer positioning of (α-LA-β-CN) complex to the proximity of Trp residues when compared to the two other cases. According to the resonance light scattering (RLS) measurements, the detection of a much greater RLS intensity in (α-LA-β-CN) Nano Res complex suggested the production of a larger complex. Furthermore, the conductometry outcomes displayed an increase in molar conductivity and therefore approved the occurrence of interaction between Nano Res and proteins in both binary and ternary systems. The spherical shape of Nano Res was confirmed through the results of FE-SEM and TEM analyses. The conformational changes of proteins throughout the binding of Nano Res was evaluated by circular dichroism (CD) technique, while molecular docking and MD simulations affirmed the binding of Nano Res to α-LA, (α-LA-β-LG), and (α-LA-β-CN) complexes as binary and ternary systems. These In Silico study data confirm the results of in vitro assessments. The occurrence of changes in the secondary structure of β-galactosidase was implied through the increased enzyme catalytic activity induced by the interaction of different lactose concentrations. Communicated by Ramaswamy H. Sarma

Complexation behavior of carboxymethyl short-chain amylose and quaternized chitosan

The complexation of carboxymethyl short-chain amylose (CSA) and hydroxypropyl trimethyl ammonium chloride chitosan (HACC) and the stability of CSA/HACC nanocomplex were investigated. Resonance light scattering (RLS), turbidity, nanoparticle size and zeta potential analyses revealed that the complex coacervation occurred between CSA and HACC. The mass ratio and pH markedly influenced the complexation behavior; CSA with a higher degree of substitution (DS0.2) altered the complexation at a lower mass ratio and pH, increasing the turbidity and RLS intensity. The results of particle size and zeta potential analyses indicated that CSA/HACC complexes possessed the good pH and ionic strength stability. In addition to electrostatic interactions, hydrogen bonding and hydrophobic effects were also determined to be involved in the complexation process using thermal titration calorimetry (ITC). Additionally, the process was spontaneous, and CSA with a higher DS showed stronger complexation ability. These results may enable the understanding of polysaccharide complex behaviors.

A highly sensitive dual-readout assay for perfluorinated compounds based CdTe quantum dots

Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) are two typical perfluorinated compounds (PFCs) that poss potential ecological toxicity. In this work, a fluorescence and resonance light scattering (RLS) dual-readout strategy for the detection of PFCs at picomole level based on the water-soluble CdTe quantum dots (CdTe QDs) has been proposed. It is found that the CdTe QDs exhibit a quenching in the presence of PFCs and thus serve as useful probes for PFCs. The linear ranges are 0.032–10.0 nM with a limit of detection(LOD) of 32.02 pM for PFOA and 0.044–15.0 nM with a LOD of 43.96 pM for PFOS, respectively. Meanwhile, PFCs can form complexes with CdTe QDs in acid medium, resulting in remarkable RLS signals. The enhanced RLS intensities are in proportion to the concentrations of PFOA and PFOS, respectively. And the linear ranges are 0.048–5.0 nM with a LOD of 47.78 pM for PFOA, and 0.057–5.0 nM with a LOD of 56.72 pM for PFOS, respectively. This dual-mode detection increases the reliability of the measurement. The proposed method is simple, sensitive and cost-effective, with potential applications in environmental monitoring and assessment.

Ultratrace Detection of Nickel(II) Ions in Water Samples Using Dimethylglyoxime-Doped GQDs as the Induced Metal Complex Nanoparticles by a Resonance Light Scattering Sensor.

This study aimed to synthesize dimethylglyoxime (DMG) (N-source)-doped graphene quantum dots (N-GQDs) via simultaneous pyrolysis of citric acid and 1.0% (w/v) DMG. The maximum excitation wavelength (λmax, ex = 380 nm) of the N-GQD solution (49% quantum yield (QY)) was a red shift with respect to that of bare GQDs (λmax, ex = 365 nm) (46% QY); at the same maximum emission wavelength (λmax, em = 460 nm), their resonance light scattering (RLS) intensity peak was observed at λmax, ex/em = 530/533 nm. FTIR, X-ray photoelectron spectroscopy, XRD, energy-dispersive X-ray spectroscopy, and transmission electron microscopy analyses were performed to examine the synthesized materials. The selective and sensitive detection of Ni2+ using the RLS intensity was performed at 533 nm under the optimum conditions consisting of both 25 mg L–1 N-GQDs and 2.5 mg L–1 DMG in the ammonium buffer solution of pH 9.0. The linearity of Ni2+ was 50.0–200.0 μg L–1 with a regression line, y = 5.031x – 190.4 (r2 = 0.9948). The limit of detection (LOD) and the limit of quantitation (LOQ) were determined to be 20.0 and 60.0 μg L–1, respectively. The method precision expressed as % RSDs was 4.90 for intraday (n = 3 × 3) and 7.65 for interday (n = 5 × 3). This developed method afforded good recoveries of Ni2+ in a range of 85–108% when spiked with real water samples. Overall, this innovative method illustrated the identification and detection of Ni2+ as a DMG complex with N-GQDs, and the detection was highly sensitive and selective.

Gold nanoparticles-based resonance light scattering method for the determination of phenothiazine drugs

In this work, a new method was developed for the determination of two phenothiazine drugs, namely thioridazine hydrochloride and chlorpromazine hydrochloride using gold nanoparticles-based resonance light scattering (RLS) technique. The addition of these drugs to gold nanoparticles solution in acidic medium leads to the aggregation of nanoparticles, which, in turn, causes a marked enhancement in RLS intensity at 400 nm. The aggregates were characterized by UV-Vis spectroscopy and transmission electron microscopy. The effects of important experimental factors such as pH, concentration of gold nanoparticles and incubation time on RLS signal were investigated and optimized. Under the optimum conditions, the calibration graphs were linear in the range of 3.6 - 36 and 3.5 - 30 ng/mL, for thioridazine hydrochloride and chlorpromazine hydrochloride, respectively with corresponding limits of detection of 1.1 and 1.0 ng/mL. The results indicate that the nanogold-based RLS is a very sensitive and simple method for the determination of phenothiazine drugs in pharmaceutical samples and human plasma.

Resonance light scattering spectroscopy can directly characterize protein solubility

To develop a fast, sensitive and cost-effective method based on resonance light scattering (RLS) for characterization of protein solubility to facilitate detection of changes in solubility of mutant proteins. We examined the response curve of RLS intensities to the protein concentrations in synchronous scanning mode. The curve intersection points were searched to predict the maximal concentrations of the protein in dispersion state, which defined the solubility of the protein in this given state. Bovine serum albumin (BSA, 0-50 g/L) was used as the model to investigate the influences of pH values (6.5, 7.0, and 7.4) and salt concentrations (0.05, 0.10, 0.15, and 0.20 mol/L) on the determined solubility. The solubility of glutathione S-transferase isoenzymes alpha (GSTA, 0-27.0 g/L) and Mμ (GSTM, 0-20.0 g/L) were estimated for comparison. The RLS-based method was used to determine the solubility of uricase (MGU, 0-0.4 g/L) to provide assistance in improving the solubility of its mutants. We identified two intersection points in the RLS response curves of the tested proteins, among which the lower one represented an approximation of the maximal concentration (or the solubility of the protein) in single molecular dispersion, and the higher one the saturated concentration of the protein in multiple molecular aggregation. In HEPES buffer, the two intersection points of BSA (isoelectric point 4.6) both increased with the increase of pH (6.5-7.4), and their values were ~1.2 g/L and ~33 g/L at pH 7.4, respectively; the latter concentration approached the solubility of commercial BSA in the same buffer at the same pH. The addition of NaCl reduced the values of the two intersection points, and increasing salt ion concentration decreased the values of the lower intersection points. Further characterizations of GSTA and GSTM showed that the low concentration intersection points of the two proteins were ~0.7 g/L and ~0.8 g/L, and their high concentration intersection points were ~10 g/L and ~11 g/L, respectively, both lower than those of BSA, indicating the feasibility of the direct characterization of protein solubility by RLS. The two concentration intersection points of MGU were 0.24 g/L and 0.30 g/L, respectively, and the low concentration intersection point of its selected mutant was increased by 2 times. RLS allows direct characterization of the solubility of macromolecular proteins. This method, which is simple and sensitive and needs only a small amount of proteins, has a unique advantage for rapid comparison of solubility of low-abundance protein mutants.

Resonance light scattering technique for sensitive detection of heparin using plasmonic Cu2-xSe nanoparticles

Heparin (Hep) is a mucopolysaccharide sulfate anticoagulant drug widely used in clinic and thus the quantification of Hep concentration is of great significance. In this work, a simple resonance light scattering (RLS) method for the determination of Hep concentration using plasmonic copper selenide nanoparticles (Cu2-xSe NPs) was developed. The positively-charged Cu2-xSe NPs capped by cetyltrimethyl ammonium bromide (CTAB) were aggregated by negatively-charged Hep, consequently inducing a significant enhancement in the RLS signals of plasmonic Cu2-xSe NPs. Under the optimal reaction conditions, the increased RLS intensity is linearly correlated with the concentrations of Hep in the range of 0.01–0.60 μg mL−1 (R2 = 0.999), with a low detection limit (LOD) of 4.0 ng mL−1 (3σ). This method offered a simple, sensitive and selective strategy for determining Hep, which can be further successfully applied to quantify Hep in the heparin sodium injection.

A label-free resonance light scattering biosensor for nucleic acids using triple-helix molecular switch and G-quadruplex nanowires

In this work, a label-free resonance light scattering (RLS) biosensor based on triple-helix molecular switch (THMS) and G-quadruplex nanowires (G-wires) for HAV DNA and microRNA-31 detection was developed. The target can combine with the loop sequences of triple-helix, and opened the triple-helix structure as well as liberated the G-rich sequences which were self-assembled into G-wires in the presence of K+ and Mg2+, causing an obvious enhancement of RLS intensity. Meanwhile, the RLS signal at 304 nm was linear with the logarithm of target concentration in the range of 50 pM to 300 nM, and the limit of detection is as low as 7.1 pM for HAV DNA and microRNA-31, respectively. Moreover, qualitative analysis of HAV DNA and microRNA-31 was successfully achieved in human serum samples and cancer cell lysates. The biosensor holds a great promise for universal RLS sensing platform for sensitive detection of various targets just by changing the sequence of the THMS in the loop and be a biosensing platform for early clinical diagnosis and biomedical research.

Molecular imprinting resonance light scattering nanoprobes based on pH-responsive metal-organic framework for determination of hepatitis A virus

Molecularly imprinted polymer (HM@MIP) nanoprobes were designed form the pH-responsive polymer (dimethylaminoethyl methacrylate (DMA)) and MIL-101. This probe was applied to the selective determination of hepatitis A virus (HAV) through Resonance light scattering (RLS) technique. DMA adjusts pH of the system to facilitate the capture and release of virus by HM@MIPs as anticipated. And it results in the enhancement or weaken of RLS intensity. According to RLS intensity at 470nm, a linear concentration of 0.02-2.0nmol·L-1 and a limit of detection of 0.1pmol·L-1 were obtained within 20min. The excellent recoveries ranges from 88% to 107%, and it indicates the prominent ability of the HM@MIPs to determination HAV in human serum and their potential ability to determination virus in real applications. Graphical abstractPrinciple of preparation of the HM@MIPs and detection of virus.

Synthesis of bipolar tetradentate ligand and determination of fructose 1,6-diphosphate by resonance light scattering of its supramolecular polymer

In this paper, a novel method was established for determination of fructose 1,6-diphosphate (F-1,6-BP) based on resonance light scattering (RLS), and a type of bipolar tetradentate schiff base H4L was synthesized. The study showed that under the optimization condition with the ligand concentration of 5 nmol mL−1, pH 6.5, the reaction temperature of 25 °C, the reaction time of 30 min, RLS intensity had good linearity with the concentration of F-1,6-BP within the range of 0.4–5.0 nmol mL−1, the limit of detection was 0.16 nmol mL−1 and the relative standard deviation (RSD) was 1.83%. In vitro feasibility study, four groups of medical injections and two groups of human urine were analyzed, the RSD of six parallel experiments was approximately 2%, and the recovery value changed from 98.0 to 102.5%. As shown herein, this method has high sensitivity, good precision and recovery.

An ultrasensitive guanine wire-based resonance light scattering method using G-quadruplex self-assembly for determination of microRNA-122.

An enzyme-free resonance light scattering (RLS) method is described for the determination of microRNA-122. A guanine nanowire (G-wire) is used that consists of a predesigned DNA1 and a G-quadruplex sequence DNA2. These hybridize with microRNA-122 and partially hybridize with DNA2. After formation of stable double strands with DNA1, DNA2 is released. On addition of K+ and Mg2+ ions, the G-quadruplex sequences undergo self-assembly to form long filamentous G-wires. This increases the intensity of RLS. A 6.1 pM detection limit was obtained, and the linear response covers the 50 pM to 300nM microRNA concentration range. The method was successfully applied to the quantitation of microRNA-122 in hepatocellular carcinoma cell lysates. Conceivably, this assay can be extended to other RLS methods for biomarker detection by simply changing the sequence of DNA1. Graphical abstract The G-quadruplex sequences of DNA2 were locked with DNA1. The G-quadruplex fragments of DNA2 were released after the hybridization of microRNA-122 with DNA1. These liberated G-quadruplex sequences were self-assembled into long filamentous guanine nanowires (G-wires) which increased resonance light intensity in the presence of Mg2+.

Assay of miRNA in cell samples using enhanced resonance light scattering technique based on self aggregation of magnetic nanoparticles.

miRNAs are regarded as potential biomarkers correlated with the development and progression of many diseases. However, it is a challenge to construct a sensitive method to detect them without using time-consuming radioactive labeling or complex amplification strategies. A facile resonance light scattering (RLS) system was developed for the detection of miRNA employing magnetic nanoparticles (MNPs) as RLS probes. MNPs were coated with streptavidin. DNA probes were modified on the surface of MNPs based on the specific interaction of streptavidin and biotin forming MNPs@DNA probes. MNPs@DNA probes dispersed in homogeneous media causing low RLS signal. miRNA hybridized with DNA probes resulting in the aggregation of MNPs and inducing the enhancement of RLS intensity. miRNAs were determined successfully with limit of detection at 0.9picomole per liter (pM). The potential clinical application of the present biosensor was also demonstrated by measuring miRNAs in human normal and cancer cells, and human serum samples.

Resonance light scattering aptasensor for urinary 8-hydroxy-2'-deoxyguanosine based on magnetic nanoparticles: a preliminary study of oxidative stress association with air pollution.

An aptamer based method is described for the determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG) using resonance light scattering (RLS). Magnetic nanoparticles (MNPs) were employed as RLS probes. The probe DNA was placed on the surface of MNPs, which produces a rather low RLS signal. If, however, probe DNA hybridizes with the aptamer against 8-OHdG, a sandwich structure will be formed. This results in a significant enhancement of RLS intensity. The aptamer was used as the recognition element to capture 8-OHdG. 8-OHdG has a stronger affinity for the aptamer than probe DNA, and the conformation of the aptamer therefore switches from a double-stranded to a G-quadruplex structure. As a result, MNPs labeled with probe DNA are released, and RLS intensity decreases. The method allows 8-OHdG to be detected with a linear response in the 32 pM - 12.0nM concentration range and an 11 pM limit of detection (at 3.29SB/m, according to the recent recommendation of IUPAC). The MNPs can be reused 5 times by applying an external magnetic field for collection. The method was successfully applied to analyze human urine samples for its content of 8-OHdG. It was also found that the levels of 8-OHdG noticeably increased with the increase of the Air Quality Index. Conceivably, the method is a viable tool to investigate the relationship between 8-OHdG levels and the effect of air pollution. Graphical abstract A reusable sensing strategy was constructed to detect urinary 8-OHdG based on "turn-off" resonance light scattering. The LOD was as low as 11 pM. This study showed some preliminary data for the association between oxidative stress and air pollution.

Structural transition of lactoferrin upon interaction with estradiol as revealed by spectroscopic techniques: a molten globule state investigation

Proteins have numerous physiological functions in the body. Their most important property is serving as depot carriers and as target molecules for many drugs. Three-dimensional fluorescence spectroscopy, zeta potential analysis, resonance light scattering (RLS), thermodynamic analysis, circular dichroism and fluorescence resonance energy transfer (FRET) measurements were performed to study the interactions between estradiol and human lactoferrin (Hlf). According to the three-dimensional fluorescence spectra, the binding of the drug to Hlf induced a slight destabilization of the protein. Circular dichroism results provided new insight into the course of structural transitions of Hlf after addition of estradiol, and revealed that a molten globule state was intermediate between the native and unfolded states. This is a compact state with a significant amount of native-like secondary structure, but a largely disordered tertiary structure. The experimental results further indicated that the fluorescence quenching mechanism between Hlf and estradiol corresponded to a static quenching procedure. The binding constant and the number of binding sites were obtained from modified Stern–Volmer diagrams. The distance r between donor and acceptor was obtained by FRET and found to be 1.96 nm for estradiol and Hlf. The critical induced aggregation concentrations (CCIAC) of estradiol on Hlf were determined by a non-linear relationship between the enhancement of the RLS intensities and drug concentrations. The zeta potential results were used to verify the existence of complexes and confirmed the CCIAC values obtained by the RLS technique. In addition, molecular modeling showed that estradiol was bound within the domain II of the C-lobe and N-lobe of the Hlf via hydrophobic interactions and hydrogen bonding.

Simply and sensitively simultaneous detection hepatocellular carcinoma markers AFP and miRNA-122 by a label-free resonance light scattering sensor

In this study, an intelligent and label-free sensor is utilized for the first time to one-spot simultaneous detection hepatocellular carcinoma markers AFP and miRNA-122 by a resonance light scattering (RLS) sensor. cDNA1 hybridizes with cDNA2 to form double-stranded DNA (dsDNA). The construction of dsDNA and methyl violet is used to form the RLS sensor via the electronic interaction. When AFP or miRNA-122 is present, the cDNA (cDNA1 or cDNA2) can bindings of target, thereby RLS intensity changed proportionally with the concentration of AFP or that of miRNA-122. The detection limits of AFP and miRNA-122 are 0.94 μg/L and 98 pM respectively, and their good linear which ranges from 5 to 100 μg/L and 200 pM to 10 nM are achieved using the assay. In the presence of miRNA-122 and AFP mixtures, AFP bound to the AFP aptamer to increase the RLS signal, and miRNA-122 bound to the miRNA-122 complementary strand to decrease the RLS signal. The RLS signal changed in response to changing AFP and miRNA-122 concentrations, so that one-spot simultaneous detection of alpha fetal protein and miRNA-122 is achieved. This method has potential practical applications in the research of hepatocellular carcinoma.

Determination of diclofenac sodium by resonance light scattering method using silver nanoparticles as probe

A sensitive, simple and novel method was developed to determine diclofenac sodium (DS) using silver nanoparticles (AgNPs) as probe by resonance light scattering (RLS) technique. It was found that DS could quench the RLS intensity of AgNPs. Moreover, the decrease in RLS intensity was linearly correlated to the concentration of DS over the range of 0.01–2.0μgmL−1. DS can be measured in a short time (5min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RLS intensities such as pH, concentration of AgNPs, reaction time, electrolyte concentration, and coexisting substances were systematically investigated and optimized. The results showed that the method had a very good selectivity and could be used conveniently for the determination of DS. The limit of detection (LOD) was 2.85ngmL−1 (3σ), and the relative standard deviation (RSD) was less than 3.6% (n=6). Possible mechanism for the RLS changes of AgNPs in the presence of DS was discussed and the method was successfully applied for the analysis of tablets and urine samples.

Ultrasensitive Detection of Protein Based on Graphene Quantum Dots with Resonance Light Scattering Technique.

In this paper, a simple, label-free and ultrasensitive resonance light scattering (RLS) method for ultratrace protein detection was investigated using graphene quantum dots (GQDs) as probes. Due to the electrostatic interaction between GQDs and protein, the RLS intensity was gradually enhanced as the protein was added into the GQDs solution. Through a series of optimization experiments, the optimal detection conditions of the GQDs solution were as follows: pH = 7.4, 2 M ion concentration and 60 μM GQDs. Under the optimized conditions, the linear correlation between the GQDs and the concentration of protein was observed from 10 μM to 60 μM with the correlation coefficient (R2) of 0.9978, and the limit of detection (LOD) was 2.4 μM. Time-resolved fluorescence spectrum showed that the electron transition channel was not affected by the protein self-assembled on the surface of GQDs, which indicated that the interaction between GQDs and protein was mainly the electrostatic interaction. The proposed method revealed that the RLS enhancement effect from the self-assembled GQDs-protein hybrid nano-system provided a green and simple method to establish ultrasensitive biosensors.

Application of polyacrylonitrile nanofibers decorated with magnetic carbon dots as a resonance light scattering sensor to determine famotidine

In this study, a novel resonance light scattering (RLS) sensor was synthesized using polyacrylonitrile nanofibers decorated with magnetic carbon dots (MCDs@NFs) nanocomposite and applied for famotidine (FMD) determination. The MCDs@NFs nanocomposite was synthesized by combining electrospinning and a simple one-step hydrothermal method. Different methods were applied in order to characterize the MCDs@NFs nanocomposite such as: scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Light scattering properties of the synthesized nanocomposite in the presence or absence of FMD have been selected as the detection signal considering the fact that FMD addition increases the RLS intensities of the system. Thus, the prepared nanocomposite was employed as a RLS sensor to detect FMD. A linear response was observed under the optimal conditions in range of 0.15–50.0μmolL−1 with detection limit of 0.04μmolL−1. The MCDs@NFs nanocomposite was effectively capable in determining FMD in real samples and the results were close to those results obtained by reversed-phase HPLC method (RP-HPLC).

Size Distribution of Nanoparticles in Solution Characterized by Combining Resonance Light Scattering Correlation Spectroscopy with the Maximum Entropy Method.

A single-nanoparticle detection method is reported for characterizing the size distribution of noble metal nanoparticles in solution by combining resonance light scattering correlation spectroscopy (RLSCS) with the maximum entropy method (MEM). The principle of RLSCS is based on the autocorrelation analysis of the resonance light scattering (RLS) fluctuations due to Brownian motion of a single nanoparticle in a highly focused detection volume (less than 1.0 fL), which resembles fluorescence correlation spectroscopy (FCS). However, RLS intensity of nanoparticles such as gold nanoparticles (GNPs) is proportional to the sixth power of sizes according to the Mie theory, which is different from the optical properties of fluorescent molecules. Herein the present FCS theoretical model cannot be directly applied in RLSCS to characterize GNPs. In this study, we used GNPs as model samples and first established an RLSCS theoretical model for the size distribution of GNPs by using the maximum entropy method (MEM), which is called MEM-RLSCS. This model covers the contribution of single-particle brightness of GNPs to the MEM fitting process based on the Mie theory. Then we preformed computer simulations of this model. The simulated results documented that the model proposed was able to well describe the diffusion behaviors and size distribution of nanoparticles. We investigated the effects of certain factors such as size difference, the relative concentration, and single-particle brightness on the size distribution. Finally, we used the MEM-RLSCS for characterization of GNPs in solution, and the results obtained were in agreement with the size distribution of GNPs from transmission electron microscopy (TEM). This method is also suitable for characterization of other metal nanoparticles (such as silver nanoparticles) in solution and in situ study diffusion dynamics of nanoparticles in living cells.

Development of a thermosensitive molecularly imprinted polymer resonance light scattering sensor for rapid and highly selective detection of hepatitis A virus in vitro

In this study, a thermosensitive imprinted polymer coating SiO2 was developed for a resonance light scattering (RLS) thermosensitive virus-affinity sensor, which exhibited high selectivity for virus monitoring. In this sensor, N-isopropylacrylamide was a temperature-sensitive element. The recognition performance of the nanosensor for viruses was regulated by temperature control for the specific capture of the target virus at 40°C, resulting in the increase of RLS intensity and its release at 20°C. Moreover, the RLS intensity of the nanosensor significantly increased within 30min. Accordingly, a very good detection limit of 1.1pmolL−1 was obtained. The nanosensor was successfully used to detect the additional hepatitis A virus from a dilution of human serum, and recoveries in the range of 90.8% to 108.3% were attained at three spiking levels of viruses. Overall, this study addressed the problems of high nonspecific adsorption and long duration of detection process. Furthermore, a facile, rapid, and efficient tool for virus detection was provided.