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BACKGROUND OBJECTIVES: West Bengal is a dengue-endemic State in India, with all four dengue serotypes in co-circulation. The present study was conceived to determine the changing trends of circulating dengue virus (DENV) serotypes in five consecutive years (2015-2019) using a geographic information system (GIS) during the dengue season in West Bengal, India. METHODS: Molecular serotyping of dengue NS1 sero-reactive serum samples from individuals with ≤5 days of fever was performed using conventional nested reverse transcriptase-PCR. GIS techniques such as Getis-Ord Gi* hotspot analysis and heatmap were used to elucidate dengue transmission based on the received NS1-positive cases and vector data analysis was used to point out risk-prone areas. RESULTS: A total of 3915 dengue NS1 sero-positive samples were processed from most parts of West Bengal and among these, 3249 showed RNA positivity. The major circulating serotypes were DENV 3 (63.54%) in 2015, DENV 1 (52.79%) in 2016 and DENV 2 (73.47, 76.04 and 47.15%) in 2017, 2018 and 2019, respectively. Based on the NS1 positivity, dengue infections were higher in males than females and young adults of 21-30 yr were mostly infected. Getis-Ord Gi* hotspot cluster analysis and heatmap indicate that Kolkata has become a hotspot for dengue outbreaks and serotype plotting on maps confirms a changing trend of predominant serotypes during 2015-2019 in West Bengal. INTERPRETATION CONCLUSIONS: Co-circulation of all the four dengue serotypes was observed in this study, but only one serotype became prevalent during an outbreak. Representation of NS1-positive cases and serotype distribution in GIS mapping clearly showed serotypic shift in co-circulation. The findings of this study suggest the need for stringent surveillance in dengue-endemic areas to limit the impact of dengue and implement better vector-control strategies.
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Vírus da Dengue , Dengue , Masculino , Feminino , Adulto Jovem , Humanos , Sorogrupo , Dengue/epidemiologia , Vírus da Dengue/genética , Sistemas de Informação Geográfica , Índia/epidemiologia , RNA Viral/genéticaRESUMO
The antimicrobial and cytotoxic effects of zinc oxide nanomaterials are popularly thought to be occurring due to zinc ion leaching, but the exact mechanism of cytotoxicity is controversial and not fully understood. Recent studies have shown that oxygen vacancy defects in the nanoscale zinc oxide can generate reactive oxygen species (ROS) under dark conditions and may induce cytotoxicity. In this work, we show that the cytotoxicity of zinc oxide nanoparticles is directly correlated with oxygen vacancy defects that generate ROS under dark conditions. More specifically, we designed zinc oxide nanoparticles with controlled oxygen vacancy defects by controlled gallium doping and showed that the ROS generation property of zinc oxide nanoparticles under dark conditions is directly correlated with oxygen vacancy defects. Further studies show that superoxide radicals and hydrogen peroxide are the primary ROS that are produced under dark conditions. These colloidal nanoparticles are used for cell labeling and therapy via intracellular ROS generation without any light exposure. The designed nanoparticle can be used for the formulation of advanced antibacterial and antimicrobial materials and other cell therapy applications.
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Nanopartículas , Óxido de Zinco , Antibacterianos/farmacologia , Sobrevivência Celular , Nanopartículas/toxicidade , Oxigênio , Espécies Reativas de Oxigênio , SuperóxidosRESUMO
The rapid spread of viral infections demands early detection strategies to minimize proliferation of the disease. Here, we demonstrate a plasmonic biosensor to detect Dengue virus, which was chosen as a model, via its nonstructural protein NS1 biomarker. The sensor is functionalized with a synthetic single-stranded DNA oligonucleotide and provides high affinity toward NS1 protein present in the virus genome. We demonstrate the detection of NS1 protein at a concentration of 0.1-10 µg/mL in bovine blood using an on-chip microfluidic plasma separator integrated with the plasmonic sensor which covers the clinical threshold of 0.6 µg/mL of high risk of developing Dengue hemorrhagic fever. The conceptual and practical demonstration shows the translation feasibility of these microfluidic optical biosensors for early detection of a wide range of viral infections, providing a rapid clinical diagnosis of infectious diseases directly from minimally processed biological samples at point of care locations.
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Vírus da Dengue , Dengue , Animais , Biomarcadores , Bovinos , DNA , Vírus da Dengue/genética , Proteínas não Estruturais ViraisRESUMO
Complex biological fluids without pretreatment, separation, or purification impose stringent limitations on the practical deployment of label-free plasmonic biosensors for advanced assays needed in point of care applications. In this work, we present an enzyme-free plasmonic neurotransmitter dopamine biosensor integrated with a microfluidic plasma separator. This integrated device allows the in-line separation of plasma directly from the bloodstream and channels it to the active detection area, where inorganic cerium oxide nanoparticles function as local selective dopamine binding sites through strong surface redox reaction. A thorough understanding and engineering of the nanoparticles is carried out to maximize its dopamine sensitivity and selectivity. We obtain detection of dopamine at 100 fM concentration in simulated body fluid and 1 nM directly from blood without any prior sample preparation. The detection selectivity is found to be at least five-times higher compared to the common interfering species. This demonstration shows the feasibility of the practical implementation of the proposed plasmonic system in detection of variety of biomarkers directly from the complex biological fluids.
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Técnicas Biossensoriais , Dopamina/isolamento & purificação , Nanopartículas/química , Neurotransmissores/isolamento & purificação , Ácido 3,4-Di-Hidroxifenilacético/química , Cério/química , Dopamina/sangue , Humanos , Neurotransmissores/sangueRESUMO
We demonstrate that the active thermocapillary stresses induced by multiple microbubbles offer simple routes to directed self-assembly and complex but controllable micromanipulation of mesoscopic colloidal particles embedded in a liquid. The microbubbles are nucleated on a liquid-glass interface using optical tweezers. The flow around a single bubble causes self-assembly of the particles in rings at the bubble-base, while an asymmetric temperature profile generated across the bubble interface breaks the azimuthal symmetry of the flow, and induces simultaneous accumulation and repulsion of particles at different axial planes with respect to the bubble. The flow due to two adjacent bubbles leads to more diverse effects including the sorting of particles, and to local vorticity that causes radial and axial rotation of the particles - the latter being obtained for the first time using optical tweezers. The sorting is enabled by nucleating the bubbles on spatially discrete temperature profiles, while the vorticity is generated by nucleating them in the presence of a temperature gradient which once again causes a strong symmetry-breaking in the azimuthal flow. The flow profiles obtained in the experiments are explained by analytical solutions or qualitative explanations of the associated thermocapillary problem employing the Stokes and heat equations.
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BACKGROUND: Multitransfused thalassemic individuals are at high risk of developing transfusion transmitted Hepatitis C virus (HCV) infection. The aim of the study was to correlate the effects of host cytokine single nucleotide polymorphisms of TNF-α (-308 A/G) and IFN-γ (+874 A/T) in spontaneous or IFN induced treatment response in the HCV infected thalassemic individuals. METHODS: A total of 427 HCV sero-reactive thalassemic individuals were processed for HCV viral genomic diversity and host gene polymorphisms analysis of TNF-α (-308 A/G) and IFN-γ (+874 A/T). RESULTS: Out of 427 HCV sero-reactive individuals, 69.09% were found to be HCV RNA positive with genotype 3 as the predominant infecting strain (94.29%). Study highlighted that, A allele was significantly associated with (pâ¯<â¯.05) spontaneous clearance of HCV infection and G allele was correlated with viral persistence at TNF-α (-308) gene polymorphism. Whereas in case of IFN-γ (+874) SNPs, A allele was significantly responsible (pâ¯<â¯.05) for spontaneous clearance than T allele. Our study also indicated that in relapsed cases, IFN-γ (+874) T allele is more responsible than A allele. Though no significant correlation was found at both TNF-α (-308) and IFN-γ (+874) gene polymorphism among SVR and relapsed thalassemic patients. CONCLUSION: A allele at both TNF-α (-308) and IFN-γ (+874) were strongly associated with spontaneous clearance among this population. But in case of SVR and relapsed cases no significant association was found. This cytokine gene polymorphisms pattern will help clinicians to take an informed decision about therapeutic management of HCV infected thalassemic individuals.
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Transfusão de Sangue , Estudos de Associação Genética , Hepacivirus/fisiologia , Hepatite C/genética , Interferon gama/genética , Polimorfismo de Nucleotídeo Único/genética , Talassemia/genética , Fator de Necrose Tumoral alfa/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Genótipo , Hepacivirus/genética , Hepatite C/sangue , Hepatite C/tratamento farmacológico , Humanos , Interferon-alfa/uso terapêutico , Masculino , RNA Viral/genética , Talassemia/virologia , Adulto JovemRESUMO
Background & objectives: Multiple transfusions in ß-thalassaemia patients undergoing regular transfusion regimen are at a risk of developing transfusion transmitted infections, including hepatitis C virus (HCV). The present study was conducted to investigate the association of HCV viraemia and genotype with clinical parameters in HCV seroreactive ß-thalassaemic individuals. Methods: A total of 172 HCV seroreactive ß-thalassaemic individuals aged between 2-35 yr with at least 25 units of blood transfusion were catagorized into four groups (2-12 yr, group 1; 13-19 yr, group 2; 20-29 yr, group 3; 30-35 yr, group 4). Aged matched control samples (n=87; ß-thalassaemics without HCV infection) were also included. HCV RNA was detected by nested reverse transcriptase polymerase chain reaction (RT-PCR) based on 5' UTR of HCV genome, viral load was determined by real-time RT-PCR. Nested RT-PCR amplified partial core region was used for DNA sequencing. Liver function parameters [serum total bilirubin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST)] were also determined. Results: Of the 172 HCV seroreactive individuals, 59.30 per cent (n=102) were HCV RNA positive. HCV viral load ranged from 173 to 32.04×10[5] IU/ml; 87.65 per cent were infected with HCV genotype 3. Liver enzymes, such as ALT, AST and serum total bilirubin were significantly elevated in all age groups compared to control groups. Serum ferritin levels were found to be high in all individuals, but 16.27 per cent of HCV-infected individuals with >10,000 IU/ml viral load also showed high ferritin levels (>1500 µg/l) where the majority of them were infected with HCV genotype 3. Interpretation & conclusions: HCV genotype 3 was the major circulating genotype among ß-thalassaemia patients in this region. Our findings indicated an association between HCV replication and hepatic iron load and also highlighted the need for sensitive quantitative RT-PCR-based detection of HCV RNA in the high risk population.
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Transfusão de Sangue , Hepatite C/complicações , Talassemia beta/complicações , Adolescente , Adulto , Alanina Transaminase , Criança , Pré-Escolar , Genótipo , Hepacivirus , Hepatite C/genética , Hepatite C/fisiopatologia , Humanos , Índia , Ferro/sangue , Pessoa de Meia-Idade , RNA Viral , Adulto JovemRESUMO
BACKGROUND: Hepatitis C virus (HCV) is the major posttransfusion infection in multitransfused individuals in India with thalassemia major. To our knowledge, this study is the first conducted to correlate and comprehend the effects of the host interleukin (IL)28B gene polymorphism at loci rs12979860 and rs8099917 in spontaneous or interferon (IFN)-induced treatment response in the HCV-seroreactive individuals with thalassemia major. STUDY DESIGN AND METHODS: A total of 557 HCV-seroreactive individuals with thalassemia were processed for HCV viral genotyping and host IL28B single-nucleotide polymorphism analysis at loci rs12979860 and rs8099917. RESULTS: Of 557 individuals, 70.92% were found to be HCV RNA positive with Genotype 3 (95.18%) as predominant strain. A favorable CC allele at locus rs2979860 and TT allele at rs8099917 were 75.31 and 77.16%, respectively, which was strongly associated with spontaneous clearance of infection (p < 0.05). Of 85 IFN-treated cases, 56 achieved sustained virologic response (SVR) whereas 27 were relapsed cases. Among these patients who achieved SVR, a favorable CC/TT allele at rs12979860/rs8099917 was found to be predominant with 76.79 and 66.07%, respectively, whereas in the case of relapsed patients, unfavorable CT (55.56%) and TG (59.26%) alleles were found to be predominant. Additionally, low serum ferritin level was significantly associated with SVR. CONCLUSION: CC at rs12979860 and TT at rs8099917 was strongly associated with spontaneous clearance and SVR in the population with thalassemia. Low age group and low serum ferritin level are important cofactors. This allelic pattern will aid clinicians in making an informed decision about prognosis and therapeutic management.
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Transfusão de Sangue , Hepatite C Crônica/patologia , Hepatite C Crônica/virologia , Interleucinas/genética , Polimorfismo de Nucleotídeo Único/genética , Talassemia/genética , Talassemia/terapia , Adolescente , Alelos , Criança , Pré-Escolar , Feminino , Ferritinas/sangue , Genótipo , Hepacivirus/patogenicidade , Hepatite C Crônica/sangue , Hepatite C Crônica/genética , Humanos , Interferons , Masculino , Talassemia/sangue , Talassemia/virologia , Resultado do TratamentoRESUMO
Dengue virus infection is a major cause of morbidity within the endemic tropical and subtropical regions of the world. Dengue virus has four distinct serotypes with specific clinical manifestations. In this study, we observed the changing pattern of dengue serotypes, age-wise dengue infection and useful sero-detection methods needed in a dengue endemic region. We identified dengue serotypes during a period of 5 years among patients with dengue symptoms visiting one of the largest tertiary care infectious disease hospitals of eastern India in Kolkata. A total of 433 dengue RNA positive samples were isolated from 712 acute dengue suspected cases. Age wise distribution highlighted the susceptible age group being >21 years (24.02%) followed by 11-15 years (21.71%) and 5-10 years (21.02%) of the total infected population. Higher numbers of infected cases were found within females as they are involved in more indoor works. The period of study experienced two dengue outbreaks one in 2008 and another in 2012. For early dengue detection, NS1 was found to be more confirmatory than IgM ELISA regarding sensitivity and specificity. DENV-1, 2, and 4 serotypes were the common circulating strains from 2008 until 2010, after which DENV-3 serotype infections rise and led to a massive dengue outbreak in Kolkata with increased numbers of DHF and DSS cases in 2012. The finding within our study emphasizes the public health importance of such prospective surveillance programs with respect to the changing dengue viral etiology and serotypes. J. Med. Virol. 88:1697-1702, 2016. © 2016 Wiley Periodicals, Inc.
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Vírus da Dengue/genética , Vírus da Dengue/imunologia , Dengue/epidemiologia , Dengue/virologia , Surtos de Doenças , Dengue Grave/epidemiologia , Dengue Grave/virologia , Adolescente , Adulto , Fatores Etários , Criança , Pré-Escolar , Dengue/diagnóstico , Dengue/imunologia , Vírus da Dengue/classificação , Ensaio de Imunoadsorção Enzimática , Monitoramento Epidemiológico , Feminino , Humanos , Índia/epidemiologia , Masculino , Estudos Prospectivos , RNA Viral/sangue , Sorogrupo , Sorotipagem , Dengue Grave/diagnóstico , Dengue Grave/imunologia , Fatores Sexuais , Proteínas não Estruturais Virais/imunologia , Adulto JovemRESUMO
The extreme asymmetry of species richness distribution across the tree of life has always intrigued evolutionary biologists. Two competing explanations have been proposed to explain this pattern-the clade age hypothesis and diversification rate variation. While these two scenarios may not be mutually exclusive, to what extent time and diversification rates interact to explain species richness patterns remains understudied. Here, we investigate the relative influence of these two scenarios using tarantulas (Family: Theraphosidae) as a model. Tarantulas represent a speciose group of spiders found worldwide but exceptionally diverse in South America. These spiders show two distinct patterns of microhabitat use (ground-dwelling or arboreal) and defense strategies (presence or absence of urticating hairs). Using various trait-independent and dependent diversification models, we test the clade age hypothesis, the role of microhabitat, antipredator defense strategy, and geography in influencing diversification rates. Our results suggest that clade age is the primary predictor of species richness distribution across the tarantula subfamilies. However, the presence of urticating hair probably disrupted this pattern in some clades by increasing the net diversification rates, not by increasing the speciation rate but by reducing the extinction rate.
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Biodiversidade , Aranhas , Animais , Filogenia , Evolução Biológica , Geografia , Especiação GenéticaRESUMO
The accurate detection, classification, and separation of chiral molecules are pivotal for advancing pharmaceutical and biomolecular innovations. Engineered chiral light presents a promising avenue to enhance the interaction between light and matter, offering a noninvasive, high-resolution, and cost-effective method for distinguishing enantiomers. Here, we present a nanostructured platform for surface-enhanced infrared absorption-induced vibrational circular dichroism (VCD) based on an achiral plasmonic system. This platform enables precise measurement, differentiation, and quantification of enantiomeric mixtures, including concentration and enantiomeric excess determination. Our experimental results exhibit a 13 orders of magnitude higher detection sensitivity for chiral enantiomers compared to conventional VCD spectroscopic techniques, accounting for respective path lengths and concentrations. The tunable spectral characteristics of this achiral plasmonic system facilitate the detection of a diverse range of chiral compounds. The platform's simplicity, tunability, and exceptional sensitivity holds remarkable potential for enantiomer classification in drug design, pharmaceuticals, and biological applications.
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Metal-organic frameworks (MOFs) are a class of porous materials known for their large surface areas. Thus, over the past few decades the development of MOFs and their applications has been a major topic of interest throughout the scientific community. However, many current conventional syntheses of MOFs are lengthy solvothermal processes carried out at elevated temperatures. Herein, we developed a rapid light-induced synthesis of MOFs by harnessing the plasmonic photothermal abilities of bipyramidal gold nanoparticles (AuBPs). The generality of the photo-induced method was demonstrated by synthesizing four different MOFs utilizing three different wavelengths (520 nm, 660 nm and 850 nm). Furthermore, by regulating light exposure, AuBPs could be embedded in the MOF or maintained in the supernatant. Notably, the AuBPs-embedded MOF (AuBP@UIO-66) retained its plasmonic properties along with the extraordinary surface area typical to MOFs. The photothermal AuBP@UIO-66 demonstrated a significant light-induced heating response that was utilized for ultrafast desorption and MOF activation.
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Monitoring chemical levels is crucial for safeguarding both the environment and public health. Elevated levels of ammonia, for instance, can harm both humans and aquatic ecosystems, often indicating contamination from agriculture, industry, or sewage. Developing portable, high-resolution, and affordable methods for in situ monitoring of ammonia is thus imperative. Plasmonic sensors offer a promising solution, detecting ammonia by correlating changes in their optical response to the target analyte's concentration. While they are highly sensitive and can be fabricated in a variety of portable and user-friendly formats, some still require reagents or expensive optical equipment, which hinder their widespread adoption. Here, we present a self-assembled nanoplasmonic colorimetric sensor capable of directly detecting ammonia concentrations in aqueous matrices. The proposed sensor exploits the plasmonic resonance of the nanostructures to transduce changes in the chemical environment into alterations in color, offering a label-free method for real-time analysis. The sensor is fabricated using a self-assembling technique compatible with low-cost mass production based on aluminum and aluminum oxide, ensuring affordability and avoiding the use of other toxic chemicals. We developed a model to predict ammonia concentrations based on visible color change of the sensor, achieving a detection limit of 8.5 ppm. Furthermore, to address the need for on-site detection, we integrated smartphone technology for real-time color change analysis, eliminating the need for expensive, bulky optical instruments. Indeed, our approach offers a cost-effective, portable, and user-friendly solution for ammonia detection in water without the need for chemical reagents or spectrometers, making it ideal for field applications. Interestingly, this platform extends its applicability beyond ammonia detection, enabling the monitoring of various chemicals using a smartphone, without the need for any additional costly equipment.
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The scientific world is increasingly focusing on rare earth metal oxide nanomaterials due to their consequential biological prospects, navigated by breakthroughs in biomedical applications. Terbium belongs to rare earth elements (lanthanide series) and possesses remarkably strong luminescence at lower energy emission and signal transduction properties, ushering in wide applications for diagnostic measurements (i.e., bioimaging, biosensors, fluorescence imaging, etc.) in the biomedical sectors. In addition, the theranostic applications of terbium-based nanoparticles further permit the targeted delivery of drugs to the specific site of the disease. Furthermore, the antimicrobial properties of terbium nanoparticles induced via reactive oxygen species (ROS) cause oxidative damage to the cell membrane and nuclei of living organisms, ion release, and surface charge interaction, thus further creating or exhibiting excellent antioxidant characteristics. Moreover, the recent applications of terbium nanoparticles in tissue engineering, wound healing, anticancer activity, etc., due to angiogenesis, cell proliferation, promotion of growth factors, biocompatibility, cytotoxicity mitigation, and anti-inflammatory potentials, make this nanoparticle anticipate a future epoch of nanomaterials. Terbium nanoparticles stand as a game changer in the realm of biomedical research, proffering a wide array of possibilities, from revolutionary imaging techniques to advanced drug delivery systems. Their unique properties, including luminescence, magnetic characteristics, and biocompatibility, have redefined the boundaries of what can be achieved in biomedicine. This review primarily delves into various mechanisms involved in biomedical applications via terbium-based nanoparticles due to their physicochemical characteristics. This review article further explains the potential biomedical applications of terbium nanoparticles with in-depth significant mechanisms from the individual literature. This review additionally stands as the first instance to furnish a "single-platted" comprehensive acquaintance of terbium nanoparticles in shaping the future of healthcare as well as potential limitations and overcoming strategies that require exploration before being trialed in clinical settings.
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Térbio , Humanos , Térbio/química , Animais , Nanopartículas/química , Nanopartículas/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Nanopartículas Metálicas/química , Engenharia Tecidual/métodos , Nanomedicina Teranóstica/métodos , Sistemas de Liberação de Medicamentos/métodosRESUMO
The utilization of novel drug delivery systems loaded with essential oils has gained significant attention as a promising approach for biomedical applications in recent years. Plants possess essential oils that exhibit various medicinal properties, i.e., anti-oxidant, anti-microbial, anti- inflammatory, anti-cancer, immunomodulatory, etc., due to the presence of various phytoconstituents, including terpenes, phenols, aldehydes, ketones, alcohols, and esters. An understanding of conventional and advanced extraction techniques of Essential Oils (EOs) from several plant sources is further required before considering or loading EOs into drug delivery systems. Therefore, this article summarizes the various extraction techniques of EOs and their existing limitations. The in-built biological applications of EOs are of prerequisite importance for treating several diseases. Thus, the mechanisms of action of EOs for anti-inflammatory, anti-oxidant, anti-bacterial activities, etc., have been further explored in this article. The encapsulation of essential oils in micro or nanometric systems is an intriguing technique to render adequate stability to the thermosensitive compounds and shield them against environmental factors that might cause chemical degradation. Thus, the article further summarizes the advanced drug delivery approaches loaded with EOs and current challenges in the future outlook of EOs for biomedical applications.
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Silymarin, a bioflavonoid derived from the Silybum marianum plant, was discovered in 1960. It contains C25 and has been extensively used as a therapeutic agent against liver-related diseases caused by alcohol addiction, acute viral hepatitis, and toxins-inducing liver failure. Its efficacy stems from its role as a potent anti-oxidant and scavenger of free radicals, employed through various mechanisms. Additionally, silymarin or silybin possesses immunomodulatory characteristics, impacting immune-enhancing and immune-suppressive functions. Recently, silymarin has been recognized as a potential neuroprotective therapy for various neurological conditions, including Parkinson's and Alzheimer's diseases, along with conditions related to cerebral ischemia. Its hepatoprotective qualities, primarily due to its anti-oxidant and tissue-regenerating properties, are well-established. Silymarin also enhances health by modifying processes such as inflammation, ß-amyloid accumulation, cellular estrogenic receptor mediation, and apoptotic machinery. While believed to reduce oxidative stress and support neuroprotective mechanisms, these effects represent just one aspect of the compound's multifaceted protective action. This review article further delves into the possibilities of potential therapeutic advancement of silymarin and silibinin for the management of neurodegenerative disorders via mechanics modules.
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Using photons to drive chemical reactions has become an increasingly important field of chemistry. Plasmonic materials can provide a means to introduce the energy necessary for nucleation and growth of nanoparticles by efficiently converting visible and infrared light to heat. Moreover, the formation of crystalline nanoparticles has yet to be included in the extensive list of plasmonic photothermal processes. Herein, we establish a light-assisted colloidal synthesis of iron oxide, silver, and palladium nanoparticles by utilizing silica-encapsulated gold bipyramids as plasmonic heat sources. Our work shows that the silica surface chemistry and localized thermal hotspot generated by the plasmonic nanoparticles play crucial roles in the formation mechanism, enabling nucleation and growth at temperatures considerably lower than conventional heating. Additionally, the photothermal method is extended to anisotropic geometries and can be applied to obtain intricate assemblies inaccessible otherwise. This study enables photothermally heated nanoparticle synthesis in solution through the plasmonic effect and demonstrates the potential of this methodology.
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Light-induced catalysis and thermoplasmonics are promising fields creating many opportunities for innovative research. Recent advances in light-induced olefin metathesis have led to new applications in polymer and material science, but further improvements to reaction scope and efficiency are desired. Herein, we present the activation of latent ruthenium-based olefin metathesis catalysts via the photothermal response of plasmonic gold nanobipyramids. Simple synthetic control over gold nanobipyramid size results in tunable localized surface plasmon resonance bands enabling catalyst initiation with low-energy visible and infrared light. This approach was applied to the ROMP of dicyclopentadiene, affording plasmonic polymer composites with exceptional photoresponsive and mechanical properties. Moreover, this method of catalyst activation was proven to be remarkably more efficient than activation through conventional heating in all the metathesis processes tested. This study paves the way for providing a wide range of photoinduced olefin metathesis processes in particular and photoinduced latent organic reactions in general by direct photothermal activation of thermally latent catalysts.
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Piezocatalytic materials have considerable application potential in wireless therapy. Most of these applications require biocompatible nanomaterials for in vivo targeting and control of intracellular processes. However, the piezocatalytic performance of a material decreases at a nanometer size regime, and most of the biocompatible materials have poor piezocatalytic efficiency. In particular, hydroxyapatite or calcium phosphate-based nanomaterials have weak piezocatalytic properties that limit the biomedical application potential. Here, we show that anisotropic shape and Au nanoparticle conjugation can enhance the piezocatalytic property of a calcium phosphate nanomaterial by 10 times and the performance approaches that of the bulk/nanoparticle form of well-known BaTiO3. The colloidal form of calcium phosphate nanowires/nanorods/nanospheres (2-5 nm diameter and 30-1000 nm length) and their Au nanoparticle (5-8 nm) composites are prepared, and their piezoelectric properties have been investigated with piezoresponse force microscopy. It has been observed that the anisotropic nanowire structure of calcium phosphate can enhance the piezoelectric property by 2 times and Au nanoparticle conjugation can enhance it up to 10 times with a piezoelectric constant value of 72 pm/V, which is close to the value of the bulk/nanoparticle form of BaTiO3. This enhanced piezoelectric property is shown to enhance the piezocatalytic reactions by 10 times. The approach has been used to design colloidal nano-bioconjugate for selective labeling of cancer cells, followed by wireless cell therapy via medical-grade ultrasound-based intracellular reactive oxygen species generation. The developed approach and material can be extended for wireless therapeutic applications and for controlling intracellular processes.