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When exposed to different relative humidities (RHs), the optical properties of atmospheric aerosols will change because of changes in the aerosol particle size and complex refractive index (RI), which will affect haze formation and global climate change. The potential contributions of ultrafine particles to the atmospheric optical characteristics and to haze spreading cannot be ignored because of their high particle number concentrations and strong diffusibility; measurement of the optical properties of wet ultrafine particles is thus highly important for environmental assessment. Therefore, a surface plasmon resonance microscopy with azimuthal rotation illumination (SPRM-ARI) system is designed to determine the RIs of single particle aerosols with diameters of less than 100 nm in the hygroscopic growth process. Measurements are taken using mixed single particles with different mass ratios. The RIs of mixed single aerosols at different RHs are retrieved by measuring the scattering light intensity using the SPRM-ARI system and almost all the RIs of the bicomponent particles with different mass ratios decrease with increasing water content under high RH conditions. Finally, for each of the bicomponent particles, the maximum standard deviations for the retrieved RI values are only 2.06×10

Photocatalytic oxidation of toxic pollutants is a proficient technique to solve the problems associated with the treatment of bisphenol-A which is classified as 1B reprotoxic substance. In this paper, Ag2C2O4/Ag@GNS nanocomposite whereas Ag and graphene nanosheets (GNS) used as the charge carriers, which is combined through peroxymonosulfate (PMS) for the removal of bisphenol-A (BiP-A) for the first time. The XRD, UV-DRS, SEM, and TEM studies were performed to confirm the phase structure and the purity. Ag2C2O4/Ag@GNS nanocomposite exhibited superior photocatalytic performance and removal rate when compared with pure Ag2C2O4 and pure GNS. In Ag2C2O4/Ag@GNS photocatalyst, the deposited Ag on the surface of Ag2C2O4 rods effectively formed a metal and semiconductor heterostructure, thus photogenerated charge carriers were separated easily by the surface plasmon resonance effect (SPR) effect of noble Ag. Hence charge carriers lifetime has been extended to a great extent for the better photocatalytic performance. The experimental results confirmed that the O2−, OH, SO4− radicals were played major role in the photolysis process. Furthermore, the effect of the photocatalyst & PMS concentration, pH and co-existing ions towards the BiP-A degradation were studied in detail. According to the mass spectroscopy studies BiP-A pollutant was effectively deteriorated into smaller molecules and CO2, H2O. Furthermore, we have proposed the possible degradation pathway and photocatalytic mechanism for better understanding.

Silver nanoparticles are known to have antimicrobial properties. In the present paper, antibacterial activity of biosynthesized silver nanoparticles coated on low density poly ethylene films was evaluated against Escherichia coli as the representative organism. Silver nanoparticles were biosynthesized using banana peel extract as the reducing agent and characterized by means of UV–Visible spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-ray analyses. Formation of silver nanoparticles was confirmed by the Surface Plasmon Resonance spectrum with absorption maxima at 431 nm. Particles were seen to be highly polydispersed with the average size in the range of 50–390 nm. Presence of elemental silver was confirmed by the Energy dispersive X-ray spectroscopy analysis. Biosynthesized silver nanoparticles showed excellent antibacterial activity against Escherichia coli in the agar well diffusion test, with the zone of inhibition diameter measuring 19 mm. The silver nanoparticle coated low density poly ethylene film was prepared successfully and our antimicrobial studies revealed that the coated films declined the growth profile of bacteria starting from the log phase. Hence biosynthesized silver nanoparticles incorporated low density poly ethylene films can be suggested as an active packaging material for food packaging after further characterization and migration studies.

Microplastics represent an emerging environmental problem worldwide, raising ecological and food safety concerns. Compared to microplastics, there is growing evidence of an even higher abundance of submicro- and nanoplastics in the environment, but a reliable monitoring method for detecting these smaller-sized plastics is lacking. Herein we presented the application of surface-enhanced Raman scattering (SERS) for this purpose. Particles of polystyrene (PS; 600 nm) were used as the probe analyte. Gold nanourchins (AuNU; 50 nm), i.e. urchin-shaped nanoparticles with irregular spikes around the core, were used as the SERS-active substrate. The effectiveness of SERS on PS was evaluated at a single-particle level with different numbers of AuNU in order to determine the minimum conditions required for the onset of the SERS effect. Our findings suggest that SERS of a single particle of PS can be induced by as few as 1-5 particles of AuNU, and that the use of excitation wavelength at 785 nm is appropriate to meet the red-shifted surface plasmon resonance of AuNU upon aggregation. These specifications provide additional information for the development of SERS-based tools for detecting plastic particles1 µm in food and environmental samples.

Hydroxyapatite (HAp) is the major component of all boney tissues in mammals. Because of this omnipresence in the living world, HAp possesses an exceptional biocompatibility. The downside of this omnipresence, however, comes in the form of its mild to moderate biological activities. One means of augmenting these activities involves the doping of HAp with foreign ions. Here, the first synthesis and characterization of HAp doped with germanium ions is being reported. Germanium was deliberately integrated into the crystal lattice of HAp in the form of germanate anions. Approximately two thirds of the germanate ions introduced into the hydrothermal solution got incorporated into the HAp lattice, yielding the approximate stoichiometry of Ca10-x(PO4)5.62+y(GeO3)0.38(OH)2-z. Germanates replaced the phosphates of stoichiometric HAp and induced the expansion of the HAp lattice both along the screw axis of the calcium ion hexagons and in the direction parallel to the basal plane. Simultaneously, the larger size and the triple valency of the germanate ion as compared to the smaller and trivalent phosphates prompted the bond distortion and charge compensation through defect formation, which reduced the crystallinity and increased the microstrain of the HAp lattice. Vibrational spectroscopic analyses corroborated these crystallographic effects by demonstrating the enhanced heterogeneity of the environments surrounding the active modes after germanate ions were incorporated into HAp. Conforming to La Châtelier's principle, this reduction of the crystallographic order increased the capacity of the material for integration of adventitious carbonates. However, the inclusion of germanate ions induced a partial shift of these carbonates to the hydroxyl channel sites, thus decreasing the ratio of the B-type carbonation to the A-type carbonation. Introduced into HAp, germanium acted as a superb regulator of the particle size and morphology, enhancing their fineness and uniformity. Inclusion of germanate ions also increased the electrophoretic mobility and hydrodynamic surface charge density of the particles by reducing their size and by inducing a more stochastic distribution of terminal ionic groups due to the bending of the crystal facets. Overall, the doping of HAp with germanate ions facilitated the production of narrowly dispersed nanorods with a moderately enhanced structural disorder and with a pronounced potential for the biomedical niche. © 2022 The Author(s)

Silver nanoparticles (AgNPs) are highly produced in developed countries for a variety of products. Consequently, AgNPs end up being introduced in aquatic systems all over the world, and usually deposited in riverine sediments, from where they can be taken up by aquatic organisms and transferred along the food chain. The analysis of AgNPs in natural samples is not an easy task, because of their low presence and complicated reactions, which can change their speciation. The objective of this work is to help in this challenge, developing a method applicable to analyse sediment samples from any place around the world where AgNPs are suspected to be present. Firstly, four methods for the synthesis of AgNPs were investigated by Ultraviolet–visible (UV–VIS) spectroscopy and particle size analysis. The methods differed in the reducing agent used and in the concentration of the stabilising agent applied. The method including NaBH4 and SDS (sodium dodecyl sulphate) resulted to be more adequate as the Surface Plasmon Resonance (SPR) band position and width indicated. This conclusion was corroborated considering the hydrodynamic diameters and polydispersity indices of the synthesised AgNPs. The Z-average hydrodynamic diameter and the UV–VIS spectrum of AgNPs synthesised using this method indicated that the AgNPs remained kinetically stable for at least 10 days. Finally, ten potential extraction solutions were investigated, in terms of maximal extraction efficiency, but minimal effects on AgNP dissolution and aggregation. The candidate solutions ranged from deionized water and salts to strong acids and bases. The intensity of the SPR band concluded that using NaOH media the synthesised AgNPs was kinetically stable. Moreover, TEM (Transmission Electron Microscopy) images showed that the AgNPs in NaOH retained their shape and size after 10 days. Therefore, NaOH media turned out to be the best potential extractant for the analysis of sediment samples.

The optoelectronic application of gold nanoparticles is majorly influenced by certain unique features they exhibit, like surface plasmon resonance, ready functionalization and ease of conjugation with bio-analytes etc. Production of gold nanoparticles through laser ablation is the simplest method with the advantage of obtaining high purity particles. In this work, the saturation and reverse saturation behaviour during ultrafast absorption in laser ablated gold nanoparticles is studied using the Z-scan technique. The Z-scan experiment is conducted using 800 nm, 84 MHz and 120 fs intense laser pulses at different excitation intensities from 6.23 GW/cm2 to 23.37 GW/cm2. The open aperture Z-scan measurements show distinct positive region till an excitation of 17 GW/cm2 after which there is a clear cross-over into negative trend. The strength of this negative wing increases with the excitation intensity, which is featured by the nonlinear absorption due to the two-photon and three-photon absorption contributions with their respective coefficients in the range of 10-3. The optical limiting nature of these gold nanoparticles is demonstrated. An understanding of these nonlinear optical properties provides better insight in their application towards biomedical diagnostics and optical switching and limiting.

The capabilities to manipulate light-matter interaction at the nanoscale lie at the core of many promising photonic applications. Optical nanoantennas, made of metallic or dielectric materials, have seen a rapid development for their remarkable optical properties facilitating the coupling of electromagnetic waves with subwavelength entities. However, high-throughput and cost-effective fabrication of these nanoantennas is still a daunting challenge. In this work, we provide a versatile nanofabrication method capable of producing large scale optical nanoantennas with different shapes. It is developed from colloidal lithography with no dry etching required. Furthermore, both metallic and all-dielectric nanoantennas can be readily fabrication in a high-throughput fashion. Au and Si nanodisks were fabricated and employed to assemble heterostructures with monolayer tungsten disulfide. Strong coupling is observed in both systems between plasmon modes (Au nanodisks) or anapole modes (Si nanodisks) with excitons. We believe that this nanofabrication method could find a wide range of applications with the diverse optical nanoantennas it can engineer.

Elucidating the active components of traditional Chinese medicine (TCM) is essential to understand the mechanisms of TCM and promote its rational use as well as TCM-derived drug development. Recent studies have shown that surface plasmon resonance (SPR) technology is promising in this field. In the present study, we propose an SPR-based integrated strategy to screen and analyze the major active components of TCM. We used Radix Paeoniae Alba (RPA) as an example to identify the compounds that could account for its anti-inflammatory mechanism via tumor necrosis factor receptor type 1 (TNF-R1). First, RPA extraction was analyzed using an SPR-based screening system and the potential active ingredients were collected, enriched, and identified as paeoniflorin and paeonol. Next, the affinity constants of the paeoniflorin and paeonol were determined as 4.9 and 11.8 μM, respectively. Then, SPR-based competition assays and molecular docking were performed to show that the two compounds could compete with tumor necrosis factor-α (TNF-α) while binding to the subdomain 1 site of TNF-R1. Finally, in biological assays, the two compounds suppressed cytotoxicity and apoptosis induced by TNF-α in the L929 cell line. These findings prove that SPR technology is a useful tool for determining the active ingredients of TCM at the molecular level and can be used in various aspects of drug development. The SPR-based integrated strategy is reliable and feasible in TCM studies and will shed light on the elucidation of the pharmacological mechanism of TCM and facilitate its modernization.

The simplification of localized surface plasmon resonance (LSPR) detection can further promote the development of optical biosensing application in point-of-care testing. In this study, we proposed a simple light emitting diode (LED) based single-wavelength LSPR sensor modulated with bio-electron transfers for the detection of electroactive biomolecules. Indium tin oxide electrode loaded with nanocomposites of polyaniline coated gold nanorod was used as LSPR chip, and the applied electric potential was scanned at the LSPR chip for single-wavelength LSPR biosensing. Under the scanning of applied potentials, biological electron transfer of redox reaction was employed to demonstrate the bioelectronic modulation of single-wavelength LSPR for selective electroactive biomolecule detection. Without any additional recognition material, electroactive biomolecules uric acid and dopamine were detected directly with a sensitivity of 5.05 μmol/L and 7.11 μmol/L at their specific oxidation potentials, respectively. With the simplified optical configuration and selective bioelectronic modulation, the single-wavelength LSPR sensor is promising for the development of simple, low-cost, and high specificity optical biosensor for point-of-care testing of electroactive biomolecules.

Thrombus treatment faces great challenges because of the difficulties in the early diagnosis and prevention, and targeted thrombolytic therapy. As a result, there is an urgent need to explore unique strategies to achieve the multiple targets of diagnosis, treatment, and prevention (DTP) by integrating them into one nanosystem. Gold nanoparticles (AuNPs) as a classical type of inorganic nanomaterials with gold, is emergingly found effective in all stages of thrombus therapy due to the superiority of good optical properties, surface plasmon resonance, and biocompatibility. In this review, we focused on the multifunctional roles of AuNPs including visual diagnosis through optical imaging and biomarkers, thrombolytic therapy by photothermal effect and targeting delivery, and prevention of thrombosis in blood vessels and re-embolism of artificial im-plants. Especially, the application prospects of AuNPs and the optimization strategies of their nanocomposites are highlighted and discussed. It is anticipated to provide insight on the development of a more potential integrated platform for precise thrombus therapy.

In this perspective, we have highlighted the current literature and explained the synthesis, structure, morphology, modification strategies, and photocatalytic applications of emerging BiPO4-based photocatalysts. Since BiPO4 is a large bandgap photocatalyst, it uses UV light for the excitation of electrons, and also, the recombination of charge carriers is an issue in BiPO4. Various novel modification strategies of BiPO4 photocatalysts viz. defect modifications, heterojunction formation, phase-junctions, surface plasmon resonance, Schottky junction have been successfully proposed and highlighted. These modifications enhance the light absorption and inhibit the recombination of charge carriers BiPO4 photocatalyst. Finally, future aspects for further research on BiPO4-based photocatalysts are also explored. It expects that BiPO4-based photocatalysts represent a promising strategy for developing practical photocatalysts for energy and environmental remediation applications.

For better use of solar energy, the development of efficient broadband photocatalyst has attracted extraordinary attention. In this study, a ternary composite consisting of Sr2LaF7:Yb3+,Er3+ upconversion (UC) nanocrystals and Bi nanoparticles loaded BiOBr nanosheets with oxygen vacancies (OVs, SLFBB) was designed and synthesized by multistep solvent-thermal method. Mechanisms of in-situ formation of Bi nanoparticles and OVs in BiOBr/Sr2LaF7:Yb3+,Er3+ composites (SFLB) are clarified. The Bi metal and OVs enhanced the light-harvesting capacity in the region of visible-near-infrared (Vis-NIR), and promoted the separation of electron–hole (e−/h+) pairs. Furthermore, the surface plasmon resonance (SPR) effect of Bi metal can improve the energy transfer from Sr2LaF7:Yb3+,Er3+ to BiOBr via nonradiative energy transfer process, resulting in enhancing the light utilization from upconverting NIR into Vis light. Due to the synergistic effects of UC function, SPR and OVs, the SFLBB exhibited obviously enhanced photocatalytic ability for the degradation of BPA with a rate of 8.9 × 10−3 min−1, which is about 2.78 times higher than 3.2 × 10−3 min−1 of BiOBr (BOB) under UV–Vis-NIR light irradiation. This work provides a novel strategy for the project of high-efficiency Bismuth-based broadband photocatalysts, which is helpful to further understand the mechanism of enhanced photocatalysis by UC function and plasmonic effect.

Gold nanorods (AuNRs), as relatively common materials used in biomedical areas, have been synthesized by means of many methods. However, the conventional seed-mediated method is limited by complex operations and low yield. Besides, for further applications of AuNRs, well monodispersed AuNRs and tunable longitudinal surface plasmon resonance (LSPR) remain to be improved. Herein, we report a one-pot method for synthesizing AuNRs without seeding agents. In this method, we use phenols as reducing agents and hydrochloric acid and nitric acid are used to regulate the pH of the growth solution. AuNRs with the longest LSPR peak position reaching 1340 nm are prepared. Furthermore, by systematically optimizing concentrations of the reagents involved in the growth solution, different aspect ratios of AuNRs are synthesized. The facile synthesis, controllability aspect ratio, and long LSPR peak make our method promising for wider applications of AuNRs.

Biologically inspired synthesis of nanoparticles was found to be more attractive in metal nanoparticle synthesis. The present study reported an in-situ biogenic synthesis of silver nanoparticles (AgNPs) using Solanum trilobatum aqueous leaf extract. On this basis, the aqueous leaf extract of S. trilobatum acted as a reducing agent and stabilizing agent to synthesize highly stable AgNPs at ambient temperature. Eventually, the synthesized and stabilized AgNPs surface plasmon resonance was near 430 nm through a UV–visible (UV–vis) spectrophotometer. Here, the stability of the silver colloids monitored through zeta potential and mean particle size was evaluated through diffraction light scattering (DLF). Further, the average particle size was found to be 27.6 nm and spherical, confirmed with transmission electron microscopy (TEM). Also, colloidal AgNPs and aqueous extract are found to be rich sources of antioxidants and exhibit higher free radical scavenging ability. Thus, efficient inhibition with COX1 and COX2 enzymes and the protective effect with human red blood cell (HRBC) membrane stability showed significant results. These features, suggesting the possibility of the AgNPs useful to disease-modifying for treating inflammatory disorders and associated complications.

Hexagonal cesium tungsten bronze (CsxWO3) nanocrystals have attracted great attention in the field of energy-efficient windows, which exhibit the localized surface plasmon resonance (LSPR) effect and small polaron transfer in near-infrared radiation (NIR). The enhancement of the LSPR effect can be achieved by introducing aliovalent dopant into the crystal lattice, but the improvement of small polaron transfer remains a challenge. Herein, CsxWO3 nanocrystals with oxygen defects were successfully prepared by a facile one-pot method. The introduction of oleylamine in the precursor can induce the formation of oxygen defects in the crystal lattice, which leads to a higher absorption coefficient. The spectrally selective coating prepared by CsxWO3 nanocrystals with oxygen defects exhibited superior spectral selectivity with TVis, TNIR, Tlum, and Tsol of 67.11%, 11.21%, 72.59% and 49.12%, respectively.

The semiconductor-based photocatalysts with local surface plasmon resonance (LSPR) effect can extend light response to near-infrared region (NIR), as well as promote charge-carriers transfer, which provide a novel insight into designing light-driven photocatalyst with excellent photocatalytic performance. Here, we designed cost-effective wide-spectrum Zn2In2S5/W18O49 composite with enhanced photocatalytic performance based on a dual-channel charge transfer pathway. Benefiting from the synergistic effect of Z-scheme heterostructure and unique LSPR effect, the interfacial charge-carriers transfer rate and light-absorbing ability of Zn2In2S5/W18O49 were enhanced significantly under visible and NIR (vis-NIR) light irradiation. More reactive oxygen species (ROS) were formed by efficient molecular oxygen activation, which were the critical factors for both Escherichia coli (E. coli) photoinactivation and tetracycline (TC) photodegradation. The enhancement of molecular oxygen activation (MOA) ability was verified via quantitative analyses, which evaluated the amount of ROS through degrading nitrotetrazolium blue chloride (NBT) and p-phthalic acid (TA). By combining theoretical calculations with diverse experimental results, we proposed a credible photocatalytic reaction mechanism for antibiotic degradation and bacteria inactivation. This study develops a new insight into constructing promising photocatalysts with efficient photocatalytic activity in practical wastewater treatment.

Lipid nanoparticles (LNPs) are promising drug and gene carriers. Upon intravenous administration, LNPs' experience different degree of cellular uptake depending on their formulation. Currently, in vitro and in vivo studies are the gold standard for assessing the fate of nano carriers once administered, but they are time consuming and expensive. In this work, we propose a time and cost-effective method to screen a wide range of LNP formulations and select the most promising candidates for in vitro and in vivo studies. Two different approaches were explored to investigate the binding affinity between LNPs and serum proteins using sensor functionalisation with either protein specific antibody or PEG specific antibody. The first approach allowed to identify the presence of a specific protein in the protein corona of lipid particles (reconstituted and native high-density lipoproteins (rHDL and HDL), and low-density lipoproteins LDL); while the second one provided a versatile platform for the immobilisation of pegylated-particles in order to follow the interaction with serum proteins and hence predict the composition of LNP protein corona. Sensing was done using Quartz Crystal Microbalance with Dissipation (QCM-D) but the approach is extendable to other surface sensing techniques such as Surface Plasmon Resonance (SPR) or ellipsometry.

The ability of plasmonic nanostructures to efficiently harvest light energy and generate energetic hot carriers makes them promising materials for utilization in photocatalytic water spitting. Apart from the traditional Au and Ag based plasmonic photocatalysts, more recently the noble–metal–free alternative plasmonic materials have attracted ever–increasing interest. Here we report the first use of plasmonic zirconium nitride (ZrN) nanoparticles as a promising photocatalyst for water splitting. Highly crystalline ZrN nanoparticles with sizes dominating at 30–50 nm were synthesized that exhibit intense visible and near–infrared absorption due to localized surface plasmon resonance (LSPR). Without utilizing any noble metal cocatalysts such as Pt, the plasmonic ZrN nanoparticles alone showed stable photocatalytic activity for H2 evolution in aqueous solution with methanol as sacrificial electron donor. The addition of a cobalt oxide (CoOx) cocatalyst can facilitate the separation of photogenerated charge carriers and further improve the photocatalytic activity. The optimized CoOx modified ZrN photocatalyst was observed not only to activate the O2 evolution reaction with presence of electron acceptor, but also to drive overall water splitting for the simultaneous H2 and O2 evolution in the absence of any sacrificial agents.

A plasmonic Cu6Sn5/polyaniline (Cu6Sn5/PANI) nanocomposite was synthesized by chemical reduction and hydrothermal methods. The best photocatalytic overall water splitting performance was achieved by the Cu6Sn5/PANI3wt% composite, which contains 3 wt% PANI, which is approximately three times more than that of pure Cu6Sn5. Meanwhile, Cu6Sn5/PANI3wt% exhibited excellent photocatalytic stability for water splitting during the stability investigation. The dramatic promotion of the photocatalytic activity performance can be ascribed to the cocatalyst PANI. The existence of PANI can remarkably promote the separation and transfer efficiency of the photoinduced electron-hole pairs, and therefore enhance the photocatalytic activity. Our results also verify that the photogenerated charge comes from plasmonic Cu6Sn5 with the surface plasmon resonance (SPR) effect, which is different from traditional semiconductor-based photocatalysts. This work sheds some light on plasmonic photocatalyst development and provides an alternative pathway for photocatalytic reactions.

Localized surface plasmon resonance (LSPR) enhanced photocatalysis has fascinated much interest and considerable efforts have been devoted toward the development of plasmonic photocatalysts. In the past decades, noble metal nanoparticles (Au and Ag) with LSPR feature have found wide applications in solar energy conversion. Numerous metal-based photocatalysts have been proposed including metal/semiconductor heterostructures and plasmonic bimetallic or multimetallic nanostructures. However, high cost and scarce reserve of noble metals largely limit their further practical use, which drives the focus gradually shift to low-cost and abundant nonmetallic nanostructures. Recently, various heavily doped semiconductors (such as WO3-x, MoO3-x, Cu2–xS, TiN) have emerged as potential alternatives to costly noble metals for efficient photocatalysis due to their strong LSPR property in visible-near infrared region. This review starts with a brief introduction to LSPR property and LSPR-enhanced photocatalysis, the following highlights recent advances of plasmonic photocatalysts from noble metal to semiconductor-based plasmonic nanostructures. Their synthesis methods and promising applicability in plasmon-driven photocatalytic reactions such as water splitting, CO2 reduction and pollution decomposition are also summarized in details. This review is expected to give guidelines for exploring more efficient plasmonic systems and provide a perspective on development of plasmonic photocatalysis.

Bimetal nanochains (NCs) are attracting increasing attention in the fields of catalysis and electrocatalysis due to the synergistic effects in electronic and optical properties, but the fabrication of bimetal NCs remains challenging. Here, we report a general strategy named “nucleation in the irradiation then growth in the dark” for the preparation of Au/M (second metal) NCs. In the irradiation stage, the localized surface plasmon resonance (LSPR) effect of Au NPs is excited to overcome the nucleation energy barrier for the deposition of second metals (Pt, Ag and Pd). In the followed dark process, the preferential growth of second metals on the existed nucleus leads to the formation of nanochain rather than the core/shell nanostructure. In the model reaction of electrocatalytic hydrogen evolution, the optimized Au/Pt NCs showed much better performance compared with the commercial Pt/C.

Surface plasmon resonance (SPR) technology has become one of the powerful tools for real-time bioassay of various targets without needing labels. However, SPR biosensing faces great challenge with the extension of application fields due to the limited sensitivity. Herein, we report an ultrasensitive SPR biosensing strategy for detecting carcinoembryonic antigen (CEA) with the introduction of amino-functionalized Ti3C2-MXene (N-Ti3C2-MXene) nanosheets. The ultrathin Ti3C2-MXene nanosheets were prepared by hydrochloric acid (HF) etching and further modified by (3-aminopropyl) triethoxysilane (APTES) to obtain amino terminals for conjugating polyclonal anti-CEA antibody (Ab2) via covalent bonding. Staphylococcal protein A (SPA) decorated Au film was utilized as sensing platform to orientedly immobilize monoclonal anti-CEA antibody (Ab1) via its Fc region. The N-Ti3C2-MXene-Ab2 nanoconjugates were introduced to the sensing system after capture of CEA, forming sandwiched immunocomplexes on the SPR chip. A signal amplification strategy of Ti3C2-MXene-induced spontaneous gold reductive deposition on Ti3C2-MXene nanosheets was employed to further enhance sensitivity. The proposed biosensor exhibits a wide linear range for CEA determination of 10−11 to 10−6 g mL−1 with a detection limit of 1.7 pg mL−1 (S/N=3). Moreover, good reproducibility and high specificity were demonstrated by serum samples analysis, which indicates the present method holds potential in evaluating CEA in human serum for early diagnosis and monitoring of cancer.

To boost the visible light catalytic performance of typical metal-organic frameworks (MOFs) materials (MIL-68(In)-NH2), a novel stable Z-scheme Ag/Ag3PO4/MIL-68(In)-NH2 plasmonic photocatalyst was constructed by electrostatic attraction, co-precipitation reaction, and in-situ photoreduction reaction methods for the first time. The photocatalytic activities of the photocatalysts are systematically explored by the photocatalytic degradation of bisphenol A (BPA) and reduction of Cr(VI) under visible light. Ag/Ag3PO4/MIL-68(In)-NH2 displays the best photocatalytic performance among the as-prepared photocatalysts. The rate constant of BPA degradation on Ag/Ag3PO4/MIL-68(In)-NH2 is 0.09655 min−1, which is better than many reported photocatalytic materials. It also achieved a maximum rate constant of 0.02074 min−1 for Cr(VI) reduction. The boosted photocatalytic performance is due to the improved absorption caused by localized surface plasmon resonance (LSPR), effective interface charge transfer and separation, and more reactive sites provided by the large specific surface area. Besides, the photocatalytic degradation pathway of BPA is concluded according to GC-MS analysis. Finally, a more reasonable Z-scheme mechanism is speculated and verified through a series of characterizations and simulations, such as time-resolved photoluminescence spectroscopy (TRPL), electron spin resonance (ESR), and finite difference time domain (FDTD) method.

Poor visible light utilization and charge separation efficiency of TiO2 restrict its extensive application in the photocatalytic field. Herein, a specific Z-scheme TiO2-x/Cu/ZnO heterojunction was successfully constructed by atomic layer deposition (ALD) technique and spray pyrolysis technology. Benefited from the surface plasmon resonance (SPR) effect of Cu and Z-scheme heterojunction, the visible light absorption capacity was greatly enhanced. Meanwhile, ZnO nanolayer coating, prepared by ALD technique, protects Cu element to hinder its oxidation, thus enhancing the separation efficiency of photogenerated carriers. Therefore, the photocatalytic hydrogen production performance was significant improved, exhibiting a maximum value of 342.0 µmol·g−1·h−1 for the optimal B-T-0.1C-10Z (black TiO2/0.1Cu/10 nm ZnO) sample without any noble-metal cocatalyst, which is higher than pure TiO2 (310.7 µmol·g−1·h−1, with 3 wt% Pt) synthesized by spray pyrolysis method under equal conditions. In addition, a possible mechanism for the enhanced performance was briefly discussed based on the experimental results.

Constructing noble metal-doped g-C3N4/carbon composites is a feasible route to overcome the intrinsic drawbacks of pristine g-C3N4 for enhanced activity of CO2 photoreduction. Herein, a novel Ag-doped g-C3N4/biomass-derived carbon composite with hollow bird's nest-like (Ag-g-C3N4/BN-C) is designed and prepared via a simple yet effective one-step pyrolysis method. In the Ag-g-C3N4/BN-C, the highly-dispersed Ag nanoparticles (20–30 nm) with the surface plasmon resonance (SPR) effect act as a significant cocatalyst not only to efficiently trap the photogenerated electrons from g-C3N4 to boost the separation of photogenerated electron-hole pairs but also to produce additional active “hot electrons”, while the conductive quasi-spherical hollow structure of BN-C doubles the specific surface area with multiple reflections of light, providing abundant active sites and more utilization efficiency of light energy. As a result, the Ag-g-C3N4/BN-C exhibits a remarkably enhanced CO evolution rate of 33.3 μmol·g−1·h−1 without addition of any sacrificial reagents and photosensitizers, superior to those of both the pristine g-C3N4 and many reported g-C3N4-based counterparts. The findings of this work demonstrate a good indication for integrating g-C3N4 with SPR-dependence noble metal and renewable biomass-derived carbon for enhanced CO2 photoreduction, which may be extended to modify other semiconductor materials for more photocatalytic applications with enhanced activity.

This paper presents the in-situ generation of gold nanoparticles (AuNPs) by reducing chloroauric acid (HAuCl4·H2O) with low molecular weight hydroxypropyl methylcellulose (HPMC), and HPMC-AuNPs nanocomposites are developed via solution casting method. The generation of AuNPs was initially established by a swap in color from pale yellow to purple, and then by UV–Visible (UV–Vis) spectrophotometry with the surface plasmon resonance (SPR) band observed at λ = 550 nm. The functional groups accountable for the reduction of gold ions to neutral gold atoms were identified using Fourier transform infrared spectroscopy (FT-IR). The crystalline form of the AuNPs with FCC structure was shown by X-ray diffraction (XRD) studies. The size and shape evolution of the different shaped AuNPs are confirmed by the transmission electron microscopy (TEM) study which divulged the presence of triangular plate, hexagonal, quasi spherical, isosceles trapezoid and truncated triangular morphologies of the AuNPs with an average size of 12.5 nm.

In the present work biogenic synthesis of silver nanoparticles using Cissus quadarangularis aqueous leaf extract and their evaluation of antimicrobial activities. The synthesized nanoparticles were confirmed by, X-ray diffraction (XRD), UV–visible absorption (UV–Vis), Scanning electron microscopy (SEM) and Fourier transform infra-red (FT-IR) spectroscopy. The surface plasmon resonance resulted in significant absorption at 450 nm. The XRD analysis confirmed the crystalline nature of the particles and average crystallite size was found to be 35 nm. Furthermore, FT-IR study was used to identify potential biomolecules involved in the bio reduction of silver ions. Bactericidal efficacy of synthesized nanoparticles against Gram-positive and Gram-negative bacteria was confirmed using an antimicrobial activity.

Designing and constructing advanced heterojunction architectures are desirable for boosting CO2 photoreduction performance of semiconductor photocatalysts. Herein, we have prepared hierarchical ZnS@ZnIn2S4 core-shell cages with controlled particle sizes using sequential synthesis of Zeolitic imidazolate (ZIF-8) polyhedrons, ZnS cages, and ZnIn2S4 nanosheets on the ZnS polyhedron cages. ZIF-8 polyhedrons are firstly synthesized by a liquid-phase approach. The subsequent sulfidation of the ZIF-8 polyhedrons results in the formation of ZnS polyhedron cages, which act as substrates for fabricating ZnS@ZnIn2S4 core-shell cages by growing ZnIn2S4 nanosheets. The size of ZnS cages can be tuned to optimize CO2 photoreduction performance of hierarchical ZnS@ZnIn2S4 core-shell cages. The synergy of the unique hierarchical core-shell cage-like structure and heterojunction composition endows the hybrid catalyst high incident light utilization, abundant active sites, and effective separation of photoexcited charge carriers. Benefiting from these advantages, the optimized hierarchical ZnS@ZnIn2S4 core-shell cages exhibit enhanced performance for CO2 photoreduction with the CO yield of 87.43 μmol h−1g−1 and 84.3% selectivity, which are much superior to those of single ZnIn2S4 or ZnS. Upon Au decoration, the CO2 photoreduction performance of ZnS@ZnIn2S4 core-shell cages is further enhanced because of the Schottky junctions and surface plasmon resonance effect.

Using natural mineral to realize photocatalytic reduction of CO2 is promising but remains a great challenge. Herein MoO3-x quantum dots (QDs) immobilized on acid modified palygorskite (H-Pal) nanocomposite was prepared as powder photocatalyst for CO2 conversion. The effect of various mass fractions of MoO3-x on CO2 reduction was investigated. Results reveal that the 30% MoO3-x/H-Pal demonstrates remarkable CO2 photoreduction property with a CH3OH yield rate of about 6.2 μmol·g−1·h−1 under full spectrum irradiation. The MoO3−x QDs possess high localized surface plasmon resonance (LSPR) effect induced by oxygen vacancy (Ov) not only enables the efficient capture of NIR photons, but also build S-scheme heterostructure with H-Pal mediated by Ov enhancing the separation of charge carriers as well as preserving high redox potential. In addition Ov act as active sites promoting the adsorption and activation of CO2. This work may provide a cost-effective strategy for the practical application of artificial photosynthesis.

The introduction of oxygen-defects has been a versatile strategy to enhance photocatalysis efficiency. In this work, a 2D/3D Bi/BiO2-x/Bi2WO6 heterojunction photocatalyst with rich oxygen-defective was in sequence prepared through a facile solvothermal method, which displays favorable photocatalytic activity towards organic contaminants under visible-NIR light irradiation. The enhancement in photocatalytic performance can be attributed to the synergistic effect between oxygen-vacancy-rich heterojunction and the localized surface plasmon resonance induced by metallic Bi. The functional group interaction, surface morphology, crystal structure, element composition, and tuned bandgap were investigated by FT-IR, SEM, Raman shift, ICP-MS, and XPS technique. The spectrum response performance of the photocatalyst was verified by UV-visible DRS analysis. Results of photodegradation experiments toward organic contaminants showed that the prepared photocatalyst can degrade 90% of phenol in 20 mins under visible-NIR light irradiation, both Z-scheme heterojunction and the introduction of Bi metal contribute to the enhancement in the photocatalytic activity. The results of the DFT calculation suggest that the valence band-edge hybridization within BiO2-x and Bi2WO6 can effectively enhance the photocatalytic performance by increasing the migration efficiencies of electron-hole pairs. Moreover, a possible mechanism was proposed on the results of EIS, ESR and GC-MS tests. This work offers a novel insight for synthesizing efficient visible-NIR light photocatalysis by activating the semiconductors with Bi metal.

This study illustrates preparation of well-formed TiO2 and Ag/TiO2 nanoparticles (NPs) by green combustion process using Cucumis melo (Muskmelon) juice as unique fuel. Polycrystalline Ag/TiO2 NPs outline the superior photocatalytic action towards the degradation of methylene blue dye and antioxidant activity through hindrance of free radical scavenging. The PXRD pattern illustrates the existence of Ag in the TiO2 crystal lattice with the average crystallite measure of 9.09 nm and 22.8 nm for TiO2 and Ag/TiO2 respectively. FTIR spectral studies showed a decrease in the intensity upon doping with Ag owing to the arrangement of Ag NPs on the surface of TiO2 NPs. The TEM image of Ag/TiO2 exhibited almost spherical shape with average particle measure of 9.12 nm. Further, HRTEM studies evidence enhancement of the lattice fringe width upon doping and d-spacing values are in conformity with XRD results illustrating successful doping of Ag into TiO2 lattice. PL spectrum of both the NPs exhibited intense peak at 458 nm (2.69 eV) and weak peaks at 486 nm (2.53 eV) and 700 nm (1.76 eV) in the visible region. Ag/TiO2 NPs showed predominant photocatalytic property for the MB dye decomposition compared to TiO2 NPs. This is possibly owing to aid of Ag Surface Plasmon Resonance in expanding the light assimilation of TiO2 NPs from near UV region to visible range driving to better light-absorbing capability and considerably enhances charge separation in TiO2 due to doping. The results manifested that Ag/TiO2 NPs possess conformity surface structure, better photocatalytic property compared to un-doped TiO2. Both the NPs proved to have considerable DPPH free radical scavenging activities.

Transition metal dichalcogenide (TMD) monolayers, such as MoS2, possess a direct optical bandgap and are useful for emerging ultrathin optoelectronics in the visible light range, whereas their thickness limits light absorption and emission properties. To address this drawback, one promising approach is to hybridize plasmonic nanostructures with monolayer TMDs to utilize local field enhancement effects owing to localized surface plasmon resonance (LSPR). Herein, we propose a strong enhancement of the local light–matter interaction in MoS2 monolayers on naturally generated nanoscale grooves. The nanogrooves are formed at grain boundaries (GBs) of template-stripped metal film substrates that are fabricated by mechanically stripping Ag films deposited on an ultra-flat Si substrate, wherein the nanogroove densities are systematically modulated by the Ag film thickness. We observe an effective photoluminescence enhancement factor of 758 and a Raman spectroscopy intensity enhancement of approximately 5 times in MoS2 on the subwavelength-scale nanogrooves, compared with that on grain planes, which is attributed to a strong local field enhancement of the LSPR effect. Moreover, this plasmonic enhancement effect is elucidated by dark-field scattering spectroscopy and optical simulations. Our results can facilitate the utilization of density-controllable plasmonic nanogrooves synthesized without nanopatterning techniques for plasmonic hybrids on 2D semiconductors.

In this paper, a novel Au/g-C3N4/ZnIn2S4 plasma photocatalyst heterojunction composite with 3D hierarchical microarchitecture has been successfully constructed by integrating Au/g-C3N4 plasmonic photocatalyst composite with 3D ZnIn2S4 nanosheet through a simple hydrothermal process. The Au nanoparticles were firstly anchored on the surface of pristine g-C3N4 material to get Au/g-C3N4 plasmonic photocatalyst. Ascribing to the surface plasmon resonance of Au nanoparticles, the obtained Au/g-C3N4 plasmonic photocatalyst shows a significant improved photocatalytic activity toward hydrogen production from water with visible light response comparing with pristine g-C3N4. Further combining Au/g-C3N4 plasmonic photocatalyst with 3D ZnIn2S4 nanosheet to construct a heterojunction composite. Owing to the synergistic effect of the surface plasmon resonance of Au nanoparticles in Au/g-C3N4 and the heterojunction structure in the interface of Au/g-C3N4 and ZnIn2S4, the prepared Au/g-C3N4/ZnIn2S4 plasma photocatalyst heterojunction composite shows an excellent photocatalytic activity toward hydrogen production from water with visible light response, which is around 7.0 and 6.3 times higher than that of the pristine C3N4 and Znln2S4 nanosheet, respectively. The present work might provide some insights for exploring other efficient heterojunction photocatalysts with excellent properties.

In recent years green nanotechnology gained significant importance to synthesize nanoparticles due to their cost effectiveness and biosafety. In the current study, silver nanoparticles were synthesized by using extract of Spirogyra hyalina as a capping and reducing agent. The synthesized nanoparticles were characterized by UV–Visible spectroscopy, Fourier transform infrared spectroscopy, Scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractive analysis. Silver nanoparticles give a characteristic Surface Plasmon Resonance peak of 451 nm at 2.21 a.u (arbitrary unit). SEM micrograph revealed the spherical morphology and average grain size of 52.7 nm. Furthermore, antibacterial, antifungal, insecticidal, antioxidant and membrane damage activities were determined. The maximum antibacterial and antifungal activity was observed for Pseudomonas aeruginosa (18 ± 1.2 mm) and Fusarium solani (14.3 ± 0.6 mm), respectively. In membrane damage assay, Pseudomonas aeruginosa absorbed A260 wavelength and gave maximum peak values of 0.286, 0.434 and 0.629 at 25, 35 and 45 µg/mL of silver nanoparticles. The membrane damage assay confirmed that nanoparticles are involved in bacterial cell membrane damage. At 500 ppm silver nanoparticles showed 30% mortality against Tribolium castaneum (a common grain pest). The silver nanoparticles also showed potent antioxidant activity and successfully scavenged the DPPH free radicals upto 53.43 ± 0.17, 43.26 ± 0.97, 31.39 ± 0.33, 24.62 ± 0.85, and 14.13 ± 0.12% at a concentration of 400, 200, 100, 50, and 25 µg/mL of nanoparticles, respectively. It is concluded that silver nanoparticles can easily be synthesized by using green algae Spirogyra hyalina as a capping and reducing agent. Silver nanoparticles showed potent biomedical activities and thus can be used for therapeutic applications invitro and invivo.

As competitive photocatalysts, Cu2O nanoparticles meet with severe photogenerated carries recombination and insufficient light absorption, leading to the poor photocatalytic performance. Herein, the truncated Cu2O-Au (CA) binary and Cu2O-Au-TiO2 (CAT) ternary octahedra with Au nanoparticles (Au NPs), preferentially supported on the (110) and (100) planes of Cu2O, are synthesized for efficient photocatalytic degradation reactions. The photodegradation rates of MO of CA1 (Cu2O-Au containing 1 wt % Au) and CAT are as high as 95.61% and 96.5% under 60 min of visible light irradiation, respectively. On the one hand, the synergistic function of localized surface plasmon resonance (LSPR) of Au NPs and Schottky barrier accelerate the separation and transfer of photogenerated carriers. On the other hand, a Z-scheme electron transfer system is constructed in CAT to promote the photodegradation performance. According to the finite-difference-time-domain (FDTD) simulation result, there is a strong electric field enhancement at the contact sites between Au, Cu2O and TiO2, which accelerates the electron transfer to a large extent and separates the electron-hole pairs. Therefore, this work may provide an approach for the synthesis and applications of multiple heterostructure catalyst.

CsxWO3 nanocrystals which exhibit localized surface plasmon resonance (LSPR) and small polaron transfer in wavelength of the near-infrared radiation have attracted great attention to fabricate the spectrally selective coating. Enhancing the LSPR and small polaron transfer of CsxWO3 nanocrystals is effectively achieved by introducing aliovalent dopant into its empty trigonal tunnels of the crystal lattice, but the lack of controllable synthesis process reserves some essential issues unanswered with respect to the effects of the dopant concentration on absorption coefficient, free carrier density and carrier mobility. Herein, Li-doped CsxWO3 nanocrystals were successfully prepared with the highest reported absorption coefficient, which demonstrated stronger absorption performance than the CsxWO3 nanocrystals without Li doping. The introduction of lithium into the crystal structure as a cation dopant can enhance the free carrier density of the nanocrystals, which leads to a higher absorption coefficient. The absorption coefficient variation of LSPR and small polaron transfer of Li-doped CsxWO3 nanocrystals was explained by the free carrier density and carrier mobility. This doping strategy allows CsxWO3 nanocrystals to become spectrally tunable within the wavelength of near-infrared radiation. When the Li/W molar ratio was 0.4, the free carrier density reached 10.22 × 1014 cm−3. The spectrally selective coating prepared by Li-doped CsxWO3 nanocrystals displayed excellent spectral selectivity with TVis, TNIR, Tlum, and Tsol of 68.79 %, 9.17 %, 72.61 % and 47.95 %, respectively. This doping strategy provides a promising potential to improve the spectral tunability of CsxWO3 nanocrystals for the practical application of energy-saving windows.

Plant material used to synthesize metal nanoparticles, which considered a green technology. In this respect, using fresh and dry Alhagi plant, a non-toxic, eco-friendly, and cost-effective for the synthesis of ZnO nanoparticles have been devised. X-ray diffraction (XRD), UV–visible spectroscopy (UV–Vis), transmission electron microscopy, FTIR analysis, TEM, scanning electron microscopy (SEM), and atomic force microscopy (AFM) used to characterize the produced nanoparticles. The ZnO nanoparticles found to be crystalline in nature with a single phase, according to XRD examination and the average crystallite size calculated using the Scherer's formula was about 20.3 and 22.6 for ZnO by fresh and dry plant respectively. For the sample obtained by fresh Alhagi plant extract shown clear Plasmon resonance, while dry Alhagi plant extract ZnO Nps shown tiny Plasmon resonance. The band gaps of ZnO NPs using fresh plant extract were 3.12 and 3.5 eV, while the band gaps of ZnO prepared from dry plant extract ZnO Nps were 3.15 eV. By FTIR analysis Chemical bond formations of zinc oxide confirmed. TEM analysis of ZnO NPs prepared by fresh plant and dry plant, it found the size in range from 25 to 100 nm and 35 to 100 nm respectively. The SEM images of the NPs have different shape and size in range nanoscale. AFM of ZnO NPs showing mounds-like structure and the grains are homogenous and aligned vertically.

Here in present work we studied the antibacterial and anticancer activity of gold nanoparticles (AuNPs), which are prepared through eco-friendly method using chloroauric acid and Pergulariadaemia leaves extract. The formation of the AuNPs and its structural features were fully examined by UV-Vis, SEM, HR-TEM and XRD analysis. The prepared AuNPs exhibited very high intense surface plasmon resonance (SPR) band in between 520 and 551 nm. SEM images showed AuNPs as spherical like morphology and HR-TEM images reveals the well-distributed AuNPs with average size of 30 nm. Further it was subjected to study antibacterial activity with various bacterial strains. The AuNPs coated cotton fabric has shown significant improvement in antibacterial activity against these strains. AuNPs coated cotton fabric display a superior UV-protection efficiency and it also exhibited finite anticancer response against HepG2 cell line.

Metal oxide-based plasmonics is an emergent field for which indium tin oxide (ITO) is a promising material. Improving the performance of ITO-based surface plasmon resonance (SPR) sensors requires a deeper knowledge of their optical and electrical properties. The effects of microstructural parameters and defects on mobility, which strongly influences SPR in the near-IR regime was explored. The proposed model incorporates different scattering mechanisms and non-parabolic conduction bands to obtain realistic values of mobility. The results show that larger grain sizes and higher carrier concentrations in ITO thin films improve SPR performance at near-IR wavelengths as low as 1300 nm

In the present work, the preparation of nanocomposite films of poly(vinyl alcohol) (PVA) embedded with in situ generated gold nanoparticles (AuNPs) by UV-B irradiation is reported. The formation of AuNPs showed surface Plasmon resonance (SPR) peak in the wavelength range of 532–558 nm, confirmed by UV–Visible (UV–Vis) spectroscopy. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the AuNPs with FCC crystal structure. FT-IR analysis suggests the interaction between AuNPs and PVA through intra/intermolecular hydrogen bonding. Surface morphology was found by scanning electron microscopic (SEM) analysis. The as-prepared PVA/Au nanocomposite films showed enhanced electrical conductivity over pure PVA.

In the interesting class of transition metal oxides, molybdenum oxides and its derivatives are exceptionally anticipated because of their particular optical and structural properties. At room temperature, molybdenum trioxide is a wide band gap semiconductor with enhanced exciton binding energy. In nature, MoO3 in three forms which are α, β and h-forms (α-orthorhombic, β-monoclinic, h- hexagonal phase). The synthesis and material properties of α-MoO3 nano crystals are reported under this study. Localized surface Plasmon resonance is a resonance with incident light of co-operative oscillations of free charge carriers in nano range material (LSPR). Such kind of plasmonic interactions exhibit by MoO3 nanoparticles due to movement of electron at different defect states. This concept has been used in to several functional materials and devices. We efficaciously synthesised α-MoO3 by one-pot hydrothermal route. Arranged nano sheet like structure was found as assured by FESEM. The synthesised nanostructure revealed noble optical and structural properties which was confirmed by X-ray diffraction (XRD), Field emission Scanning electron microscopy (FESEM), Ultra violet-Visible technique (UV–VIS), Fourier transform Infra-red (FT-IR) data. Energy dispersive X-ray spectrum (EDS) showed elemental composition present in synthesized material with no contaminants.

Wide-light absorption performance and efficient carrier separation ability are the necessary conditions for excellent photocatalytic materials. In this research, g-C3N4 QDs (CN QDs) and Au nano-particles (NPs) co-modified CeO2/Fe3O4 micro-flowers (MFs) photocatalyst (CACeF) has been prepared. CO2 photoreduction experiments showed that the composite had obviously enhanced photoreduction activity and photocatalytic stability. The yields of CO and CH4 over it as catalyst in 4 h is about 5 and 8 times greater than that of pure CeO2. Photoelectrochemical tests showed that the heterojunction between CN QDs and Au NPs can greatly improve the carrier separation ability and the light-utilization efficiency of photocatalysts. Besides, the excellent electronic transmission performance of Au NPs provided a specific channel for the electron transmission, and the strong local surface plasmon resonance (LSPR) of Au NPs resulted in a lot of hot-electrons can directly take part in the CO2 photoreduction. The synergistic effect between CN QDs and Au NPs can further enhance the photocatalytic activity of the photocatalyst. Fe3O4 QDs can ensure the effective recovery and reuse of the composite without affecting the photocatalytic performance of composite. Finally, a potential photoreduction mechanism of CN QDs and Au NPs co-modified CeO2/Fe3O4 MFs photocatalyst were discussed in total.

The overexpression of human epidermal growth factor receptor 2 (HER2) is recognized as a hallmark of several solid tumors, and the anti-HER2 monoclonal antibody and its engineered variants have been developed as therapeutic or diagnostic tools for HER2-overexpressing cancers. Here, we demonstrate the first example of extracellular production of an anti-HER2 single-chain variable fragment (scFv) in Escherichia coli via a non-peptide-guided secretion. The initial construct expressing an engineered green fluorescent protein-fused scFv was successful in extracellular secretion, but the expressed protein appeared to be readily truncated before the final purification. Alternatively, by adding Triton X-100 to the culture media, maltose-binding protein (MBP)-fused scFv could be secreted without significant truncation, and homogeneous purification of the intact protein was enabled. The affinity of the MBP-fused scFv to the extracellular domain of HER2 was confirmed by enzyme-linked immunosorbent assay, and the dissociation constant of the finally isolated scFv estimated by surface plasmon resonance was approximately 0.2 nM, which was superior to the other known anti-HER2 scFvs. Given that anti-HER2 scFv is an invaluable asset for developing various therapeutic or diagnostic agents for cancers, we expect that our method for the extracellular production will enable a better manufacturing process for its industrial application.

In the exploitation of nanozymes possessing intrinsic enzyme-like activities for cancer therapy, minor focus has been devoted to plasmonic nanostructures with localized surface plasmon resonance (LSPR)-driven properties. Here, we report the application of unique peroxidase-mimicking plasmonic photo-nanozymes coupling tumor-microenvironment-responsive reactive oxygen species generation with photothermal effect for effective combinatorial therapy. The well-defined anisotropic photo-nanozyme is synthesized by selectively depositing Pd nanoparticles on the tips of gold nanobypyramids. Intrinsic peroxidase-like properties with 1.5-fold-activity enhancement under photoexcitation are ascribed to a Pd-induced hot electrons/holes separation with efficient H2O2 decomposition. The LSPR-induced photocatalytic/photothermal combinatorial effects are remarkably enhanced upon H2O2 addition, critically suppressing the cell survival rate under near-infrared light. An effective decomposition of cell-signaling H2O2 additionally reveals prominent expression hindrance of vascular endothelial growth factor and hypoxia-inducible factor 1α. Our seminal findings uncover an interrelation between LSPR-induced phenomena and biomimetic fingerprints, valuable to overcome the shortcomings of conventional photodynamic therapy.

Gram-positive enhancer matrix (GEM) nanoparticles are often used in mucosal immunity, preparation of subunit vaccines or as an immune adjuvant due to its good immunological activities in recent years. Here, we designed and screened out a high affinity peptide ligand PL23, which could specifically target the non-epitope region of Classic Swine Fever Virus (CSFV) E2 protein, by virtual screening technology, enzyme linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) test. The OD value of PL23 at 450 nm was reached 1.982, and the KD value of it was 90.12 nM. Its binding capacity to protein was verified by SDS-PAGE as well. PL23 was subsequently conjugated to GEM nanoparticles by dehydration synthesis generating GEM-PL23 particles, and the GEM-PL-E2 particles were assembled after incubated with CSFV E2 protein. The cytotoxic test indicated that PL23, CSFV E2 protein, GEM nanoparticles, GEM-PL23 particles and GEM-PL-E2 particles were not toxic to cells and GEM nanoparticles could significantly promote the growth of APCs at high concentration for 1 h, p

Membrane fouling is an ongoing challenge in the membrane filtration process. Herein, a photocatalytic membrane comprising a reactive layer was fabricated by engineering partially reduced graphene oxide/Ag nanoparticles/MIL-88A (prGO/Ag/M88A, pGAM) photocatalysts on the PVDF substrate membranes. Benefiting from the high conductivity of prGO and the surface plasmon resonance (SPR) effect of Ag nanoparticles (Ag NPs), the photo-sensitivity of the prGO/Ag/M88A is significantly enhanced. Compared to the membrane in the dark condition, the pGAM membrane displayed an enhanced dye removal efficiency (∼99.7%) and significantly improved permeability (∼189 L·m−2·h−1 bar−1) towards dye contaminants based on the synergistic filtration/photo-Fenton processes. Significantly, the membrane retained high perm-selectivity after 10 cyclic runs (183 L·m−2·h−1 bar−1 of permeability and 98.1% of dye removal), and its nano-channel structure did not collapse under high pressure (0.1–0.4 MPa). The membrane also exhibits antifouling properties with a high water flux recovery of more than 90%. In addition, the pGAM membrane exhibited a high MB degradation efficiency (∼90%) when it is directly used as a photocatalyst in the photo-Fenton system. The mechanism of the self-cleaning is also proposed through quenching experiments. The results of this study demonstrate that this self-cleaning membrane has huge promise for membrane anti-fouling and wastewater remediation.

Low redox ability and severe photocorrosion limit the photocatalytic activity of metal sulfides. Herein, step-scheme (S-scheme) heterojunction composited by diethylenetriamine (DETA) ammoniated MnS (α-MnS) and Bi2MoO6 with Bi surface plasmon resonance (SPR) was successfully fabricated (Bi-5 %M/BMO). This special electron transport structure effectively suppresses the photocorrosion of α-MnS and makes photocatalysts with high redox ability. DETA was protonated to form positively charged ammonium ions and they are easy to combine with acid gas CO2, reducing the activation energy of CO2, building an efficient catalytic reaction system, and improving CO2 reduction efficiency. The CO evolution rate of Bi-5 %M/BMO (61.11 μmol g-1h−1) is 2.42, 7.89 and 5.01 times greater than that of 5 %M/BMO, pure α-MnS hollow spheres and Bi2MoO6, respectively. This indicates that Bi SPR effect can promote the separation of photon-generated electron-hole pairs dramatically. The ammoniated S-scheme heterostructure decorated with the SPR effect may provide a new perspective to design heterojunction.

Quantification of specific antibody responses is critical in determining activation of MHCII-dependent immune memory and is generally performed by enzyme-linked immunosorbent assay (ELISA). Antibody avidity for a particular antigen is also informative of the quality of the adaptive immune response following vaccination. Avidity can be determined by chaotropic elution ELISA, pre-absorption ELISA, or surface plasmon resonance (SPR), although multimeric antibodies such as IgM are problematic for SPR. ELISA-based assays are very time consuming, require secondary antibody reagents, and are poorly repeatable. Here we demonstrate that biolayer interferometry (BLI) using an Octet HTX instrument can robustly and reproducibly quantify and determine avidity of specific IgM for an antigen directly from fish serum in a single step. We collected sera from giant grouper (Epinephelus lanceolatus) that had been vaccinated with the hapten 2,4-dinitrophenol conjugated to keyhole limpet hemocyanin (DNP-KLH) and from control fish injected with phosphate buffered saline. The specific IgM in the serum and its avidity for DNP were quantified via ELISA and BLI. BLI was precise and highly repeatable for determination of the quantity and avidity of antibody in the serum compared to ELISA. The wet-lab preparation and machine running time for BLI was 3–5 times faster than ELISA to generate the same amount of data. The ELISA inter-plate variation significantly affected reproducibility while BLI was consistent and repeatable between samples and plates. Indeed, the consistency of BLI data indicated that technical triplicates were redundant. Biological replication alone was sufficient to elucidate the effect of treatments. However, BLI required a lower serum dilution than ELISA for similar sensitivity, and thus more serum was required to produce high resolution data. BLI is an extremely high-throughput assay, providing teleost serum IgM quantification and avidity data as a single-step, agile alternative to ELISA.

It is of crucial importance to know the quality of ultrathin films deposited on surface plasmon resonance (SPR) sensors prior to adsorption experiments. In this study, the optical properties of ultrathin cellulose nanocrystal films with various polymorphs (cellulose I, cellulose II and the hybrid of cellulose I/II), which deposited on gold surface of SPR sensors, were determined by a two-medium SPR technique and the influences of the second medium were assessed as well. The measured refractive index for ultrathin cellulose nanocrystal films with polymorphs of cellulose I, I/II and II was 1.453, 1.462 and 1.464, respectively, with a low margin of error about 0.2%. The porosity of according CNC films on SPR sensors was assessed to be 20.8%, 19.0%, and 18.5%. The measured film thickness for all deposited cellulose nanocrystal films was in the range of 25–35 nm, with a margin of error about 5%, accorded well with that examined by quartz crystal microbalance. The results showed that SPR surveys combined with Winspall analysis allow for simultaneous determination of the thickness, refractive index and the derived porosity, and provide a facile in situ quality control for the modified SPR sensors prior to adsorption experiments.