Establishment and application of a gold nanoparticle-based immunochromatographic test strip for the detection of avian leukosis virus P27 antigen in egg white samples.

Avian leukemia is an infectious tumorous disease of chickens caused by subgroup A of the avian leukemia virus (ALV-A), which mainly causes long-term viremia, slow growth, immune suppression, decreased production performance, multi-tissue tumors, and even death. The infection rate of this disease is very high in chicken herds in China, causing huge economic losses to the poultry industry every year. We successfully expressed the specific antigen protein of ALV (P27) through recombinant protein technology and screened a pair of highly sensitive monoclonal antibodies (mAbs) through mouse immunity, cell fusion, and antibody pairing. Based on this pair of antibodies, we established a dual antibody sandwich ELISA and gold nanoparticle immunochromatographic strip (AuNP-ICS) detection method. In addition, the parameters of the dual antibody sandwich ELISA and AuNP-ICS were optimized under different reaction conditions, which resulted in the minimum detection limits of 0.2 ng mL-1 and 1.53 ng ml-1, respectively. Commonly available ELISA and AuNP-ICS products on the market were compared, and we found that our established immune rapid chromatography had higher sensitivity. This established AuNP-ICS had no cross-reactivity with Influenza A (H1N1), Influenza A (H9N2), respiratory syncytial virus (RSV), varicella-zoster virus (VZV), Listeria monocytogenes listeriolysin (LLO), and Staphylococcal enterotoxin SED or SEC. Finally, the established AuNP-ICS was used to analyze 35 egg samples, and the results showed 5 positive samples and 30 negative samples. The AuNP-ICS rapid detection method established by our group had good specificity, high sensitivity, and convenience, and could be applied to the clinical sample detection of ALV-A.

Development of a gold nanoparticle-based lateral flow immunochromatographic assay for the rapid and quantitative detection of thymidine kinase 1 in human serum.

Thymidine kinase 1 (TK1) is a marker of cell proliferation that can be used for early screening, treatment monitoring, and evaluating the prognosis of patients with tumors. The main purpose of this study was to develop clinically applicable TK1 antibodies, establish an appropriate detection method, and provide material and technical support for the research and clinical application for different types of tumors. Experimental mice were immunized with the C-terminal 31 peptide of human TK1 to screen monoclonal cell lines capable of stably secreting specific antibodies. Monoclonal antibodies were then prepared, purified and screened for optimal pairing following the identification of purity and isotype. Finally, based on the principles adopted by the double-antibody sandwich detection method, we constructed a lateral flow immunochromatographic assay (LFIA) to quantify the concentration of TK1 in serum samples when using a gold nanoparticle-labeled anti-TK1 monoclonal antibody as a probe. The limit of detection for TK1 in serum was 0.31 pmol/L with a detection range of 0.31-50 pmol/L. The spiked recoveries ranged from 97.7% to 109.0% with an analytical precision of 5.7-8.2%; there was no cross-reactivity with common proteins in the serum. The established LFIA also exhibited good consistency with commercially available chemiluminescent immunoassay kits for the detection of clinical samples. The LFIA developed in this study has the advantages of high sensitivity, accuracy, reproducibility and strong specificity, and provides a new technical tool for the quantitative detection of TK1.

Ultrasensitive detection of imatinib in human serum using a gold-based paper sensor.

Imatinib is the tyrosine kinase inhibitor of choice for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. However, imatinib has drawbacks such as drug resistance and significant differences in pharmacokinetics within patients. Therefore, a colloidal gold-based immunochromatographic assay (CG-IA) was developed for measuring and monitoring imatinib in human serum. An imatinib derivative containing carboxyl groups was used for the synthesis of the immunogen, and 4-(4-methyl-1-piperazinylmethyl) benzoic acid was selected as the hapten for the heterologous coating antigen. Next, a highly sensitive and specific monoclonal antibody (mAb), 2F7 was screened for the construction of a CG-IA, with an IC50 value of 0.091 ng/mL. For the qualification of imatinib in human serum, the visual limit of detection (vLOD) and cut-off values of the CG-IA were 2 and 20 ng/mL, respectively. For quantitative detection, the calculated LOD value of the CG-IA was 0.068 ng/mL, with a linearity range of 1.004 and 23.087 ng/mL. The recovery rate of spiked serum samples was between 88.24 % and 104.75 %. In addition, the concentration of imatinib in the serum samples from 10 patients was detected by CG-IA and revealed a good correlation with those from LC-MS/MS. These results indicated that the developed gold-based paper sensor could become an effective tool for the rapid monitoring of imatinib in human serum samples.

Sensitive and Selective Dual-Mode Responses to Reactive Oxygen Species by Chiral Manganese Dioxide Nanoparticles for Antiaging Skin.

Excessive accumulation of reactive oxygen species (ROS) can lead to oxidative stress and oxidative damage, which is one of the important factors for aging and age-related diseases. Therefore, real-time monitoring and the moderate elimination of ROS is extremely important. In this study, a ROS-responsive circular dichroic (CD) at 553 nm and magnetic resonance imaging (MRI) dual-signals chiral manganese oxide (MnO2 ) nanoparticles (NPs) are designed and synthesized. Both the CD and MRI signals show excellent linear ranges for intracellular hydrogen peroxide (H2 O2 ) concentrations, with limits of detection (LOD) of 0.0027 nmol/106 cells and 0.016 nmol/106 cells, respectively. The lower LOD achieved with CD detection may be attributable to its higher anti-interference capability from the intracellular matrix. Importantly, ROS-induced cell aging is intervened by chiral MnO2 NPs via redox reactions with excessive intracellular ROS. In vivo experiments confirm that chiral MnO2 NPs effectively eliminate ROS in skin tissue, reduce oxidative stress levels, and alleviate skin aging. This approach provides a new strategy for the diagnosis and treatment of age-related diseases.

Chiral Nanomaterials for Cancer Vaccines.

Chirality is a fundamental characteristic of living organisms and is commonly observed at the biomolecule, cellular, and tissue levels. Chiral nanomaterials play an irreplaceable role in nanomedicine and nanobiology because of their unique enantioselectivity with biological components. Here, research progress relating to chiral nanomaterials in the field of vaccines is reviewed, including antigen presenting systems, immune adjuvants, and cancer vaccines. First, the common synthesis methods are outlined for different types of chiral nanomaterials, as well as their chiral sources, optical properties, and potential biological applications. Then, the application of chiral nanomaterials are discussed in the field of vaccines with reference to the promotion of antigen presentation and activation of the immune system for tumor immunotherapy. Finally, the current obstacles and future research directions of chiral nanomaterials are revealed with regard to regulating the immune system.

Immunological strip sensor for the rapid determination of niacin in dietary supplements and foods.

Herein, four haptens of niacin (Vitamin B3, VB3) were designed, and after a series of experiments, it was concluded that hapten D had the best immune effect. To avoid false positives in the detection of real samples, a monoclonal antibody (mAb) against VB3 was prepared by a matrix effect-enhanced mAb screening method. The concentration of the inhibition rate reaching 50% (IC50) was 603.41 ng mL-1 and the limit of detection (LOD) using an indirect enzyme-linked immunosorbent assay (ic-ELISA) was 54.89 ng mL-1. A lateral flow immunochromatographic assay (LFIA) based on gold nanoparticles was established to detect the concentration of VB3 in compound vitamin B tablets and infant formulas, with a visual LOD of 5 µg mL-1. Using a handheld reader, the quantitative LOD was calculated to be 0.60 µg mL-1. The contents of the compound vitamin B tablets and infant formulas were also verified by liquid chromatography. Therefore, the LFIA developed in this study can be applied to the specific identification and rapid detection of niacin in nutritional dietary supplements, thus meeting the market's demand for efficient niacin detection methods.

Chiral Iron Oxide Supraparticles Enable Enantiomer-Dependent Tumor-Targeted Magnetic Resonance Imaging.

The chemical, physical and biological effects of chiral nanomaterials have inspired general interest and demonstrated important advantages in fundamental science. Here, chiral iron oxide supraparticles (Fe3 O4 SPs) modified by chiral penicillamine (Pen) molecules with g-factor of ≈2 × 10-3 at 415 nm are fabricated, and these SPs act as high-quality magnetic resonance imaging (MRI) contrast agents. Therein, the transverse relaxation efficiency and T2 -MRI results demonstrated chiral Fe3 O4 SPs have a r2 relaxivity of 157.39 ± 2.34 mM-1 ·S-1 for D-Fe3 O4 SPs and 136.21 ± 1.26 mM-1 ·S-1 for L-Fe3 O4 SPs due to enhanced electronic transition dipole moment for D-Fe3 O4 SPs compared with L-Fe3 O4 SPs. The in vivo MRI results show that D-Fe3 O4 SPs exhibit two-fold lower contrast ratio than L-Fe3 O4 SPs, which enhances targeted enrichment in tumor tissue, such as prostate cancer, melanoma and brain glioma tumors. Notably, it is found that D-Fe3 O4 SPs have 7.7-fold higher affinity for the tumor cell surface receptor cluster-of-differentiation 47 (CD47) than L-Fe3 O4 SPs. These findings uncover that chiral Fe3 O4 SPs act as a highly effective MRI contrast agent for targeting and imaging broad tumors, thus accelerating the practical application of chiral nanomaterials and deepening the understanding of chirality in biological and non-biological environments.

A gold-based immunochromatographic strip for the specific detection of tacrolimus in whole blood.

Tacrolimus is a macrolide immunosuppressant widely used in organ transplantation. Due to the narrow treatment window, therapeutic drug monitoring of the clinical application of tacrolimus is necessary. In this study, a carboxyl group introduced at the hydroxyl or carbon positions of tacrolimus was used to couple with carrier protein to synthesize complete antigens. After screening different immunogens and coating antigens, a highly-sensitive and specific monoclonal antibody (mAb) 4C5 was obtained, with a half inhibitory concentration (IC50) value of 0.26 ng mL-1 determined by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). A colloidal gold-based immunochromatographic strip (CG-ICS) was established to monitor tacrolimus in human whole blood based on the mAb 4C5. Through visual observation, it was found that the visual limit of detection (vLOD) and cut-off value of qualitative detection were 1.0 and 20.0 ng mL-1, respectively. The calculated LOD (cLOD) value of quantitative detection was 0.16 ng mL-1, and the linear range was 0.48-7.57 ng mL-1. In addition, the results of the CG-ICS for analyzing real positive samples of human whole blood were basically consistent with those of LC-MS/MS. Therefore, the CG-ICS was suitable for rapid and accurate clinical monitoring of tacrolimus.

Chiral nanomaterials for biosensing, bioimaging, and disease therapies.

Chirality exists in every corner of nature and is closely associated with the phenomenon of life. The unique optical properties and enhanced enantioselectivity of chiral nanomaterials mean that they excel in many applications in nanobiology and nanomedicine. Here, we comprehensively review the progress that has been made toward the use of chiral nanomaterials in biosensing, bioimaging, and disease therapies. The construction strategies for three different types of chiral nanomaterials and their chirality-generating mechanisms are first generalized. We then focus on the biological applications of these chiral nanomaterials, ranging from chirality-based ultrasensitive detection and multifunctional imaging to therapeutic purposes. Finally, we present an in-depth discussion of the current challenges and future prospects in the utilization of these exciting materials.

Photoinduced elimination of senescent microglia cells in vivo by chiral gold nanoparticles.

Parkinson's disease (PD) is an age-related neurodegenerative disease, and the removal of senescent cells has been proved to be beneficial for improving age-associated pathologies in neurodegeneration disease. In this study, chiral gold nanoparticles (NPs) with different helical directions were synthesized to selectively induce the apoptosis of senescent cells under light illumination. By modifying anti-B2MG and anti-DCR2 antibodies, senescent microglia cells could be cleared by chiral NPs without damaging the activities of normal cells under illumination. Notably, l-P+ NPs exhibited about a 2-fold higher elimination efficiency than d-P- NPs for senescent microglia cells. Mechanistic studies revealed that the clearance of senescent cells was mediated by the activation of the Fas signaling pathway. The in vivo injection of chiral NPs successfully confirmed that the elimination of senescent microglia cells in the brain could further alleviate the symptoms of PD mice in which the alpha-synuclein (α-syn) in cerebrospinal fluid (CFS) decreased from 83.83 ± 4.76 ng mL-1 to 8.66 ± 1.79 ng mL-1 after two months of treatment. Our findings suggest a potential strategy to selectively eliminate senescent cells using chiral nanomaterials and offer a promising strategy for alleviating PD.

Enantiomer-dependent immunological response to chiral nanoparticles.

Chirality is a unifying structural metric of biological and abiological forms of matter. Over the past decade, considerable clarity has been achieved in understanding the chemistry and physics of chiral inorganic nanoparticles1-4; however, little is known about their effects on complex biochemical networks5,6. Intermolecular interactions of biological molecules and inorganic nanoparticles show some commonalities7-9, but these structures differ in scale, in geometry and in the dynamics of chiral shapes, which can both impede and strengthen their mirror-asymmetric complexes. Here we show that achiral and left- and right-handed gold biomimetic nanoparticles show different in vitro and in vivo immune responses. We use irradiation with circularly polarized light (CPL) to synthesize nanoparticles with controllable nanometre-scale chirality and optical anisotropy factors (g-factors) of up to 0.4. We find that binding of nanoparticles to two proteins from the family of adhesion G-protein-coupled receptors (AGPCRs)-namely cluster-of-differentiation 97 (CD97) and epidermal-growth-factor-like-module receptor 1 (EMR1)-results in the opening of mechanosensitive potassium-efflux channels, the production of immune signalling complexes known as inflammasomes, and the maturation of mouse bone-marrow-derived dendritic cells. Both in vivo and in vitro immune responses depend monotonically on the g-factors of the nanoparticles, indicating that nanoscale chirality can be used to regulate the maturation of immune cells. Finally, left-handed nanoparticles show substantially higher (1,258-fold) efficiency compared with their right-handed counterparts as adjuvants for vaccination against the H9N2 influenza virus, opening a path to the use of nanoscale chirality in immunology.

Ultrasmall Magneto-chiral Cobalt Hydroxide Nanoparticles Enable Dynamic Detection of Reactive Oxygen Species in Vivo.

Biological application of chiral nanoparticles (NPs) has aroused enormous levels of attention over recent years. Here, we synthesized magneto-chiral cobalt hydroxide (Co(OH)2) NPs that exhibited strong chiroptical and unique magnetic properties and applied these NPs to detect and monitor reactive oxygen species (ROS) in living cells and in vivo. Circular dichroism (CD) and magnetic resonance imaging (MRI) signals of the magneto-chiral Co(OH)2 NPs exhibited a wide intracellular ROS detection range from 0.673 to 612.971 pmol/106 cells with corresponding limits of detection (LOD) at 0.087 and 0.179 pmol/106 cells, far below that of currently available probes; the LOD for d-aspartic acid coated Co(OH)2 NPs (d-Co(OH)2 NPs) was 5.7 times lower than that for l-aspartic acid coated Co(OH)2 NPs (l-Co(OH)2 NPs) based on the CD signals. In addition, d-Co(OH)2 NPs also exhibited dynamic ROS monitoring ability. The high levels of selectivity and sensitivity to ROS in complex biological environments can be attributed to the Co2+ oxidation reaction on the surface of the NPs. Furthermore, magneto-chiral Co(OH)2 NPs were able to quantify the levels of ROS in living mice by fluorescence and MRI signals. Collectively, these results reveal that magneto-chiral Co(OH)2 NPs exhibit a remarkable ability to quantify ROS levels in living organisms, and could therefore provide new tools for exploring chiral nanomaterials as a potential biosensor to investigate biological events.

Facet-Dependent Biodegradable Mn3 O4 Nanoparticles for Ameliorating Parkinson's Disease.

Parkinson's disease (PD) is a common neurodegeneration disease. Unfortunately, there are no effective measures to prevent or inhibit this disease. In this study, biodegradable Mn3 O4 nanoparticles (NPs) in different shapes are prepared and enclosed them by {100}, {200} and {103} facets that exhibit facet-dependent protection against neurotoxicity induced by oxidative damage in a cell model of PD. Notably, Mn3 O4 nanorods enclosed by {103} facets exhibit high levels of enzyme-like activity to eliminate reactive oxygen specie in vitro. It is also determined that the uptake pathway of Mn3 O4 NPs into MN9D cells is mediated by caveolin. The data demonstrate that Mn3 O4 nanorods can be taken up by cells effectively and confer excellent levels of neuroprotection while the biodegradation of Mn3 O4 NPs in vivo is confirmed by photoacoustic image of Mn3 O4 NPs in brain at 60 d. Furthermore, the oxygen scavenging effect created by Mn3 O4 nanorods is successfully applied to a mouse model of PD; the amount of α-synuclein in the cerebrospinal fluid of PD mice is reduced by 61.2% in two weeks, thus demonstrating the potential application of facet-directed Mn3 O4 NPs for the clinical therapy of neurodegenerative disease.

Chiral Plasmonic Triangular Nanorings with SERS Activity for Ultrasensitive Detection of Amyloid Proteins in Alzheimer's Disease.

Chiral plasmonic nanomaterials have attracted unprecedented attention due to their broad applications in biomedicine, negative refractive index, and chiral sensing. Here, using a wet-chemistry process, chiral triangular Au nanorings are fabricated with a platinum (Pt) framework (l/d-Pt@Au triangular nanorings, named l/d-Pt@Au TNRs). The l/d-Pt@Au TNRs exhibit strong optical activity with a g-factor of 0.023 and can be used effectively for the discrimination of enantiomers due to selective resonance coupling between the induced electric and magnetic dipoles associated with enantiomers and the chiral plasmonic TNRs, also known as the surface-enhanced Raman scattering-chiral anisotropy (SERS-ChA) effect. The chiral d-Pt@Au TNRs represent a label-free SERS platform that can be applied to detect Aß monomers and fibrils, the hallmarks of Alzheimer's disease (AD), achieving a limit of detection (LOD) down to 0.045 × 10-12 m and 4 × 10-15 m for 42-residue-long amyloid-ß (Aß42 ) monomer and fibrils, respectively. Furthermore, chiral d-Pt@Au TNRs can also be successfully carried out to detect Aß42 proteins in AD patients with ultrahigh levels of sensitivity, thus allowing picogram quantities of Aß42 proteins to be identified. This research opens up an avenue for the use of chiral plasmonic nanomaterials as ultrasensitive SERS substrates to early diagnosis of protein-misfolding diseases.

Improved Reactive Oxygen Species Generation by Chiral Co3 O4 Supraparticles under Electromagnetic Fields.

One of the most common methods to treat thromboembolism is the use of thrombolytic drugs to activate fibrinolytic protease. The aim of this treatment was to initiate the lysis of fibrin; however, there are many side-effects associated with this form of treatment. Herein, we fabricated chiral Co3 O4 supraparticles (SPs) with a g-factor of up to 0.02 at 550 nm and paramagnetic performance applied in the treatment of thromboembolism under an electromagnetic field (MF). In vitro experiments showed that d-SPs degraded blood clot within 8 hours under MF. Compared to l-SPs, d-SPs exhibited much stronger thrombolytic ability and effectively enhanced the survival rate of thrombosis model mice more than 70 % in the 25 d of observation. The results of mechanism study showed that under MF, the level of reactive oxygen species (ROS) produced by d-SPs were 1.5 times higher than that of l-SPs, which might be attributed to the chiral-induced spin selectivity effects.

Ultrasmall Copper (I) Sulfide Nanoparticles Prevent Hepatitis†B Virus Infection.

Hepatitis B virus (HBV) poses a severe threat to public health and social development. Here, we synthesized 4±0.5 nm copper (I) sulfide (Cu2 S) nanoparticles (NPs) with 46 mdeg chiroptical property at 530 nm to selectively cleavage HBV core antigen (HBcAg) and effectively blocked HBV assembly and prevented HBV infection both in vitro and in vivo under light at 808 nm. Experimental analysis showed that the chiral Cu2 S NPs specific bound with the functional domain from phenylalanine23 (F23 ) to leucine30 (L30 ) from HBcAg primary sequence and the cutting site was between amino acid residues F24 and proline25 (P25 ). Under excitation at 808 nm, the intracellular HBcAg concentration was reduced by 95 %, and in HBV transgenic mice, the levels of HBV surface antigen (HBsAg) and HBV DNA were decreased by 93 % and 86 %, respectively. Together, these results reveal the potential nanomedicine for HBV control and provide fresh tools for viral infection.

Self-limiting self-assembly of supraparticles for potential biological applications.

Nanotechnology has largely spurred the development of biological systems by taking advantage of the unique chemical, physical, optical, magnetic, and electrical properties of nanostructures. Self-limiting self-assembly of supraparticles produce new nanostructures and display great potential to create biomimicking nanostructures with desired functionalities. In this minireview, we summarize the recent developments and outstanding achievements of colloidal supraparticles, such as the driving forces for self-limiting self-assembly of supraparticles and properties of constructed supraparticles. Their application values in biological systems have also been illustrated.

Stimulation of neural stem cell differentiation by circularly polarized light transduced by chiral nanoassemblies.

The biological effects of circularly polarized light on living cells are considered to be negligibly weak. Here, we show that the differentiation of neural stem cells into neurons can be accelerated by circularly polarized photons when DNA-bridged chiral assemblies of gold nanoparticles are entangled with the cells' cytoskeletal fibres. By using cell-culture experiments and plasmonic-force calculations, we demonstrate that the nanoparticle assemblies exert a circularly-polarized-light-dependent force on the cytoskeleton, and that the light-induced periodic mechanical deformation of actin nanofibres with a frequency of 50 Hz stimulates the differentiation of neural stem cells into the neuronal phenotype. When implanted in the hippocampus of a mouse model of Alzheimer's disease, neural stem cells illuminated following a polarity-optimized protocol reduced the formation of amyloid plaques by more than 70%. Our findings suggest that circularly polarized light can guide cellular development for biomedical use.

Correction: SERS- and luminescence-active Au-Au-UCNP trimers for attomolar detection of two cancer biomarkers.

Correction for 'SERS- and luminescence-active Au-Au-UCNP trimers for attomolar detection of two cancer biomarkers' by Aihua Qu et al., Nanoscale, 2017, 9, 3865-3872, DOI: .

Chiral Cux Coy S Nanoparticles under Magnetic Field and NIR Light to Eliminate Senescent Cells.

In the present study, chiral Cux Coy S nanoparticles (NPs) were developed to selectively induce apoptosis of senescent cells using both an alternating magnetic field (AMF) and near infrared (NIR) photon illumination. The chiral effects on living cells were investigated, and d-Cux Coy S NPs showed about 2.5 times higher of internalized ability than l-NPs. By modifying beta 2 macroglobulin (MG), senescent cells were effectively eliminated by d-Cux Coy S NPs without damaging the activities of normal cells under AMF and photon illumination. Compared to the individual application of NIR illumination and AMF, their synergistic effect induced the production of caspase-3 with a much shorter treatment time and higher efficiency due to the more serious photon-induced cellular redox and mechanical damage of cellular skeleton. Moreover, the developed strategy was successfully used to remove senescent cells in vivo. This study developed a controllable way of regulating cell activities using chiral NPs, which will provide a valuable way for treating diseases and promoting health.