Selectively colorimetric detection of cysteine with triangular silver nanoprisms

Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other 19 kinds of natural amino acids could not. Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.

One-step synthesis of Cu(Ⅱ) metal–organic gel as recyclable material for rapid, efficient and size selective cationic dyes adsorption

Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic.Herein,a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG)with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes.The Cu-MOG exhibited high efficiency,with an adsorption capacity of up to 650.32 mg/g,and rapid adsorption efficiency,with the ability to adsorb 80%of Neutral Red within 1 min.The high adsorption efficiency was attributed to its large specific surface area,which enabled it to massively bind cationic dyes through electrostatic interaction,and a nanoporous structure that promoted intra-pore diffusion.Remarkably,the Cu-MOG displayed size-selective adsorption,based on adsorption studies concerning dyes of different sizes as calculated by density functional theory.Additionally,the adsorption performance of the Cu-MOG still maintained removal efficiency of 100%after three regeneration cycles.These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.

Molecular Thermal Motion Modulated Room-Temperature Phosphorescence for Multilevel Encryption

The stimulus-responsive room-temperature phosphorescence(RTP)materials have become an increasingly significant topic in the fields of bioimaging,sensing,and anticounterfeiting.However,this kind of materials is scarce to date,especially for the ones with delicate stimulus-responsive behavior.Herein,a universal strategy for multilevel thermal erasure of RTP via chromatographic separation of host-guest doping RTP systems is proposed.The tunable host-guest systems,matrix materials,heating temperature,and time are demonstrated to allow precise six-level data encryption,QR code encryption,and thermochromic phosphorescence encryption.Mechanistic study reveals that the thermal-responsive property might be attributed to molecular thermal motion and the separation effect of the silica gel,which provides expanded applications of host-guest RTP materials such as cold chain break detection.This work offers a simple yet universal way to construct advanced responsive RTP materials.

Cellular prion protein imaging analysis with aptamer-labeled Ru(bpy)_3^(2+)-doped silica nanoparticles

A new type of highly selective aptamer-labeled fluorescent silica nanoparticles[Apt-tris(2,20-bipyridyl)ruthenium(II)@SiO2NPs]were prepared through the reverse microemulsion method by using prolonged fluorescence lifetime ruthenium complexes of tris(2,20-bipyridyl)ruthenium(II)(Ru(bpy)32?)as the source of the fluorescence for cellular prion protein imaging.Investigations showed that the newly prepared Ru(bpy)32?@SiO2NPs possessed superior advantages of strong fluorescence,low toxicity,and easy surface modification for bioconjugation.Cell imaging experiments indicated that AptRu(bpy)32?@SiO2NPs had great tendency to human bone marrow neuroblastoma cells(SK-N-SH cells),since they can express large amount of prion protein on the surface of the cell,while in HeLa cells this phenomenon disappeared for the reason that HeLa cells cannot express prion proteins.

Magnetic Bead‑Based Sandwich Immunoassay for Viral Pathogen Detection by Employing Gold Nanoparticle as Carrier

Enzyme-linked immunosorbent assay(ELISA)provides a convenient way for the detection of viral pathogens.However,conventional ELISA performed on mirowell plates suffers from poor sensitivity,laborious coating and complicated blocking procedures.Herein,we designed a sensitive colorimetric immunoassay by taking advantages of the enrichment and isolation ability of magnetic beads(MBs)and the high loading capacity of gold nanoparticles(AuNPs)for detecting respiratory syncytial virus(RSV)as a pathogen model.RSV was selectively captured and preconcentrated from samples with antibodies functionalized MBs,followed by binding with antibodies labeled AuNPs,which carrying a large amount of alkaline phosphatase(ALP)molecules for colorimetric signal amplification by catalyzing the dephosphorylation of non-colored pNPP to generate colored product pNP.After optimizing the experimental conditions based on the principle of low nonspecific signal,low cost,and high sensitivity,the analytical sensitivity of the developed immunoassay can be improved to 0.27 pg/mL,which is over sevenfold higher than that of commercially available RSV ELISA kits(2 pg/mL).In addition,the total assay time was less than 2.5 h without any pretreatment,which is much more rapid than other reported assays.Therefore,the proposed immunoassay holds great promise for the fabrication of rapid,sensitive,and economic method for the viral pathogen detection.

Plasmonic locator with sub-diffraction-limited resolution for continuously accurate positioning

Both the accurate distance measurement and positioning information at the nanoscale are important for the analysis of micro/nano interactions.Plasmon ruler has been an indispensable optical tool to detect the chemical and biological dynamic processes via distance-dependent plasmon coupling in the nearly aggregated state.But it cannot disclose the detailed and accurate information of positions and dynamic movements of its two plasmonic components owing to the inherent diffraction limit.Herein,a plasmonic locator is presented which consists of a heterotypic pair of red/blue plasmonic components with significant wavelength difference(∼150 nm).Attributed to the detuned energy(∼0.64 eV)of the two components,the plasmonic locator has the ability of sub-diffraction-limited resolution(center to center,30 nm)and accurate positioning under conventional dark-field microscopy,making the relative dynamic information of nearby red/blue components be recorded accurately at video rate.As an important complement to the current aggregate science and technology of plasmonics,this newly developed plasmonic locator presents a facile means to realize super-resolution imaging,accurate positioning,and continuous tracing in chemical and biological interactions at the single-molecule level.