Browsing by Author "Prem C. Pandey"

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A new conducting polymer-coated glucose sensor
(1988) Prem C. Pandey
A sensor for glucose formed in a one-step process is described based on a new doped polyindole film coated onto a platinum surface; a polymer-entrapped glucose oxidase electrode can be operated as an amperometric glucose sensor. The new glucose sensor has fast response time (25-40 s) with high storage and operational stability (> 35 days). Electrochemical rate constants for the new enzyme electrode have been calculated using the expressions derived by Albery et al. (J. Chem. Soc., Faraday Trans. 1, 1986, 82, 1033). It has been found that unsaturated enzyme kinetics are rate-limiting for conducting polymer-coated enzyme electrodes formed in a one-step process.
A whole cell fluorescence quenching-based approach for the investigation of polyethyleneimine functionalized silver nanoparticles interaction with Candida albicans
(Frontiers Media S.A., 2023) Atul Kumar Tiwari; Munesh Kumar Gupta; Roger J. Narayan; Prem C. Pandey
The antimicrobial activity of metal nanoparticles can be considered a two-step process. In the first step, nanoparticles interact with the cell surface; the second step involves the implementation of the microbicidal processes. Silver nanoparticles have been widely explored for their antimicrobial activity against many pathogens. The interaction dynamics of functionalized silver nanoparticles at the biological interface must be better understood to develop surface-tuned biocompatible nanomaterial-containing formulations with selective antimicrobial activity. Herein, this study used the intrinsic fluorescence of whole C. albicans cells as a molecular probe to understand the cell surface interaction dynamics of polyethyleneimine-functionalized silver nanoparticles and antifungal mechanism of the same. The results demonstrated that synthesized PEI-f-Ag-NPs were ~ 5.6 ± 1.2 nm in size and exhibited a crystalline structure. Furthermore, the recorded zeta potential (+18.2 mV) was associated with the stability of NPS and shown a strong electrostatic interaction tendency between the negatively charged cell surface. Thus, rapid killing kinetics was observed, with a remarkably low MIC value of 5 μg/mL. PEI-f-Ag-NPs quenched the intrinsic fluorescence of C. albicans cells with increasing incubation time and concentration and have shown saturation effect within 120 min. The calculated binding constant (Kb = 1 × 105 M−1, n = 1.01) indicated strong binding tendency of PEI-f-Ag-NPs with C. albicans surface. It should also be noted that the silver nanoparticles interacted more selectively with the tyrosine-rich proteins in the fungal cell. However, calcofluor white fluorescence quenching showed non-specific binding on the cell surface. Thus, the antifungal mechanisms of PEI-f-Ag-NPs were observed as reactive oxygen species (ROS) overproduction and cell wall pit formation. This study demonstrated the utility of fluorescence spectroscopy for qualitative analysis of polyethyleneimine-functionalized silver nanoparticle interaction/binding with C. albicans cell surface biomolecules. Although, a quantitative approach is needed to better understand the interaction dynamics in order to formulate selective surface tuned nanoparticle for selective antifungal activity. Copyright © 2023 Tiwari, Gupta, Narayan and Pandey.
Aggregation-Resistant, Turn-On-Off Fluorometric Sensing of Glutathione and Nickel (II) Using Vancomycin-Conjugated Gold Nanoparticles
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Atul Kumar Tiwari; Munesh Kumar Gupta; Hari Prakash Yadav; Roger J. Narayan; Prem C. Pandey
Glutathione (GSH) and nickel (II) cation have an indispensable role in various physiological processes, including preventing the oxidative damage of cells and acting as a cofactor for lipid metabolic enzymes. An imbalance in the physiological level of these species may cause serious health complications. Therefore, sensitive and selective fluorescent probes for the detection of GSH and nickel (II) are of great interest for clinical as well as environmental monitoring. Herein, vancomycin-conjugated gold nanoparticles (PEI-AuNP@Van) were prepared and employed for the detection of GSH and nickel (II) based on a turn-on-off mechanism. The as-synthesized PEI-AuNP@Van was ~7.5 nm in size; it exhibited a spherical shape with face-centered cubic lattice symmetry. As compared to vancomycin unconjugated gold nanoparticles, GSH led to the turn-on state of PEI-AuNP@Van, while Ni2+ acted as a fluorescence quencher (turn-off) without the aggregation of nanoparticles. These phenomena strongly justify the active role of vancomycin conjugation for the detection of GSH and Ni2+. The turn-on-off kinetics was linearly proportional over the concentration range between 0.05–0.8 µM and 0.05–6.4 μM. The detection limits were 205.9 and 90.5 nM for GSH and Ni2+, respectively; these results are excellent in comparison to previous reports. This study demonstrates the active role of vancomycin conjugation for sensing of GSH and Ni2+ along with PEI-AuNP@Van as a promising nanoprobe. © 2024 by the authors.
Amine-Functionalized Silver Nanoparticles: A Potential Antiviral-Coating Material with Trap and Kill Efficiency to Combat Viral Dissemination (COVID-19)
(Springer Nature, 2023) Atul Kumar Tiwari; Munesh Kumar Gupta; Govind Pandey; Shivangi Pandey; Prem C. Pandey
The outbreak of COVID-19 has drastically affected the daily lifestyles of people globally where specific Coronavirus-2 transmits primarily by respiratory droplets. Structurally, the SARS-CoV-2 virus is made up of four types of proteins in which S-protein is indispensable among them, as it causes rapid replication in the host body. Therefore, the glycine and alanine composed of HR1 of S-protein is the ideal target for antiviral action. Different forms of surface-active PPEs can efficiently prevent this transmission in this circumstance. However, the virus can survive on the conventional PPEs for a long time. Hence, the nanotechnological approaches based on engineered nanomaterials coating on medical equipments can potentially prevent the dissemination of infections in public. Silver nanoparticles with tuneable physicochemical properties and versatile chemical functionalization provide an excellent platform to combat the disease. The coating of amine-functionalized silver nanoparticle (especially amine linked to aliphatic chain and trialkoxysilane) in its nanostructured form enables cloths trap and kill efficient. PPEs are a primary and reliable preventive measure, although they are not 100% effective against viral infections. So, developing and commercializing surface-active PPEs with trap and kill efficacy is highly needed to cope with current and future viral infections. This review article discusses the COVID-19 morphology, antiviral mechanism of Ag-NPs against SARS-CoV-2 virus, surface factors that influence viral persistence on fomites, the necessity of antiviral PPEs, and the potential application of amine-functionalized silver nanoparticles as a coating material for the development of trap and kill-efficient face masks and PPE kits. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC 2022. Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
Aquatic Vegetation Species Identification and Mapping Using Multisource Data-Review
(CRC Press, 2024) Smrutisikha Mohanty; Prem C. Pandey; Prashant K. Srivastava
The monitoring of aquatic vegetation is essential for aquatic life and the entire ecosystem’s health as it provides food, protects habitat, improves water quality, and absorbs nutrients. With the advancement of geospatial technologies, the spatio-temporal distribution of aquatic vegetation can be characterized and mapped. The present study provides a comprehensive review of different aquatic flora types, their importance, and the need to map these species. The current study gives collective information on how multisource data play a crucial role in identifying aquatic plants by using various satellite-based sensors, drones, and radar data. The scientometric analysis is also performed by searching the keywords related to the theme in the Scopus database, which includes a co-occurrence map, a thematic map, trend topic analysis, and countries’ scientific production over time. Hence, the study aims to motivate future researchers to conduct extensive analysis in this potential field. © 2025 selection and editorial matter, Prem Chandra Pandey, Prashant K. Srivastava, Sanjeev Kumar Srivastava; individual chapters, the contributors.
Assessing soil organic carbon and its relation with biophysical and ecological parameters in tropical forest ecosystem India
(Taylor and Francis Ltd., 2025) Haroon Sajjad; Pavan Kumar; Prashant Kumar Srivastava; Shakti Om Pathak; Meraj Ahmed; Vikas Kumar; Manmohan J.R. Dobriyal; Preeti Kumari; Prem C. Pandey
Organic matter in soil is an essential parameter for assessing the agrodynamic productivity of soils. Forest productivity and health largely depend on soil organic carbon (SOC). This study aims to assess SOC levels and analyze their relationship with biophysical parameters in tropical forests. SOC was predicted using normalized difference vegetation index (NDVI) values derived from Sentinel-2A imagery. A total of 30 samples were collected through stratified random sampling based on NDVI values to estimate SOC. Regression analysis was performed between the estimated and predicted SOC, showing a strong correlation. The results indicated that SOC decreased with increasing soil depth in the Sariska Tiger Reserve, ranging from 8.27 - 26.54 t/ha at 5 cm depth and 1.9- 12.4 t/ha at 10 cm depth. NDVI was positively correlated with SOC, while the Bare Soil Index (BSI) showed a negative correlation. Additionally, soil pH and SOC were positively correlated, indicating high SOC levels. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Assessing the niche of Rhododendron arboreum using entropy and machine learning algorithms: role of atmospheric, ecological, and hydrological variables
(SPIE, 2022) Akash Anand; Prashant K. Srivastava; Prem C. Pandey; Mohammed L. Khan; Mukund D. Behera
Species distribution models (SDMs) have been used extensively in the field of landscape ecology and conservation biology since its origin in the late 1980s. But there is still a void for a universal modeling approach for SDMs. With recent advancements in satellite data and machine learning algorithms, the prediction of species occurrence is more accurate and realistic. Presently, four machine learning and regression-based algorithms, namely, generalized linear model, maximum entropy, boosted regression tree, and random forest (RF) are used to model the geographical distribution of Rhododendron arboreum, which is economically and medicinally important species found in the fragile ecosystem of Himalayas. To establish complex relation between the occurrence data and regional climatic and land use parameters, several satellite products, namely, MODIS, Sentinel-5p, GPM, ECOSTRESS, and shuttle radar topography mission (SRTM), are acquired and used as predictor variables to the different SDM algorithms. The performance evaluation has been conducted using the area under curve (AUC), which showed the best result for Maxent (AUC = 0.871) and poor result was observed for RF (AUC = 0.755) among all. The overall prediction confirmed the distribution of Rhododendron arboreum in the mid to high altitudes of central and southern parts of the Garhwal Division. We provide crucial evidence that combining multisatellite products using machine learning algorithms can provide a much better understanding of species distribution that can eventually help the researchers and policymakers to take the necessary step toward its conservation. © 2022 Society of Photo-Optical Instrumentation Engineers (SPIE).
Challenges and Future Implications in Monitoring and Assessment of Aquatic Ecosystems
(CRC Press, 2024) Smrutisikha Mohanty; Prem C. Pandey; Prashant K. Srivastava; Sanjeev Kumar Srivastava
Aquatic ecosystems, encompassing freshwater and marine environments, are vital for global ecological balance and human well-being. This concluding chapter delves into the diverse classifications of aquatic ecosystems and their ecological significance, emphasizing their pivotal role in supporting biodiversity, regulating climate, and providing economic services. It discusses traditional and advanced monitoring techniques, including molecular-level monitoring with environmental DNA (eDNA), traditional in situ or lab-based experiments, and regional and global monitoring using geospatial technology consisting of remote sensing, GIS, and GNSS for providing data input and processing platform. Remote sensing, in particular, is highlighted for its ability to provide comprehensive and timely information over large spatial extents, enabling robust monitoring and assessment of aquatic ecosystems. The chapter also explores the importance of remote sensing in understanding various water quality parameters, detecting environmental changes, and assessing the impacts of climate change. Challenges associated with conventional and technological approaches to studying aquatic ecosystems are discussed, alongside recent advancements in geospatial data collection and analytics. Overall, this chapter underscores the indispensable role of remote sensing in aquatic ecosystem monitoring using derived parameters and Trophic Status Index for assessing health conditions of aquatic ecosystems. Thus, it isoffering powerful tools and techniques for sustainable management and conservation efforts. © 2025 selection and editorial matter, Prem Chandra Pandey, Prashant K. Srivastava, Sanjeev Kumar Srivastava; individual chapters, the contributors.
Challenges and future possibilities toward himalayan forest monitoring
(wiley, 2022) Ayushi Gupta; Prashant K. Srivastava; K.V. Satish; Aashri Chauhan; Prem C. Pandey
The Himalayan region is one of the most sensitive of the Earth's biodiversity hotspots. This chapter explores the environmental, cultural, and socio-economic importance of the Himalayan forest ecosystem, which is prone to rapidly increasing ecological deteriorations due to deforestation, forest fire, soil erosion, climate change, and various anthropogenic disturbances and challenges to monitoring these consequences for better management of the Himalayan forest. Satellite monitoring helps to identify and collect spatial data on land-use changes, emissions, and productions from forests as well other natural resources. Species distribution models are of paramount importance in the conservation and management of biodiversity, and are considered one of the spatially quantifiable essential biodiversity variables. Forest surveys in mountainous areas are particularly difficult due to variable topography and weather patterns. Seasonal taxonomic and floristic surveys are significantly more difficult and entirely dependent on nature's grace. © 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd.
Concepts of disasters and research themes: Editorial message
(Springer International Publishing, 2024) Prem C. Pandey; Manish Pandey; R.K. Sharma; Rajesh Kumar; Prashant K. Srivastava; Gregory Giuliani
The United Nations Office for Disaster Risk Reduction (UNDRR) defines a disaster as a severe disruption of the functioning of a community or society resulting from hazardous events interacting with conditions of exposure, vulnerability, and capacity. This disruption leads to various losses and impacts, including human, material, economic, and environmental. The combination of vulnerability, hazards, and inability to reduce the potential negative consequences (of risk) results in disaster. Risk is the combination of the likelihood of an event and its negative consequences, which impact human life and infrastructure or may be defined as a degree of uncertainty resulting in potential loss (human-financial). Disasters can be broadly categorized based on the origin of the triggering event: natural disasters, anthropogenic disasters, and cascading disasters. Natural disasters include geophysical, meteorological, hydrological, climatological, and biological disasters. Anthropogenic or human-caused disasters include technological, complex emergencies, and environmental disasters. Cascading disasters include those disastrous events that occur when one initial event triggers a chain reaction of subsequent disasters. The chapter also discusses frameworks of "Disaster Risk Reduction" like the Sendai Framework for Disaster Risk Reduction (2015-2030), Sustainable Development Goals (SDGs), International Charter on Space and Major Disasters, Global Platform for Disaster Risk Reduction (GPDRR), and Regional DRR Frameworks. The chapter provides a brief but clear picture of disasters in general and natural disasters in particular, along with a thematic briefing of the chapter's subject matters included in the book. © Springer Nature Switzerland AG 2024. All rights reserved.
Earth observation applications for urban mapping and monitoring: research prospects, opportunities and challenges
(Elsevier, 2023) Aashri Chauhan; Md. Wasim; Smrutisikha Mohanty; Prem C. Pandey; Manish Pandey; Neeraj K. Maurya; Shalini Rankavat; Surya Bhushan Dubey
The significant loss of urban green spaces led to increasing Urban Heat Island (UHI) effects, environmental pollution, and other factors that have made it more difficult for societies to create healthier living conditions. The first-generation Earth Observation (EO) data like MODIS500 and GlobCover300 had less to moderate spectral and spatial resolution having limitations in the precise mapping of urban environmental variables. Monitoring and evaluating the urban environment have improved with the advancement of EO like GlobeCover30 and the Global Human Settlement Layer, which are connected to a multisensor approach, Unmanned Aerial Vehicles (UAVs) - LIDAR for 3D mapping, as well as microwave SAR applications. The present chapter offers an overview of interesting facets of urban area research that uses EO datasets directly or indirectly to address the complexity present in the urban environment for mapping and monitoring. It also offers potential future directions for creating a sustainable urban environment. It also included some case studies that demonstrate the potential of EO in mapping and monitoring urban areas, land use/land cover changes, air pollution, site suitability, road safety, urban flood monitoring, and UHI effects. © 2024 Elsevier Ltd. All rights reserved.
Earth observations for urban policies and future pathways for urban environmental research
(Elsevier, 2023) Pawan Ekka; Manjari Upreti; Shilky; Purabi Saikia; Amit Kumar; Prem C. Pandey; Prashant K. Srivastava
Urban research is now evolving, and there are several challenges that need to be addressed in the near future, which has led to pathways for further development. The scientific community must consider a multitude of options for urban monitoring, evaluation, planning, and management. In this chapter, we have provided a brief overview of different models for urban studies and research based on Earth observation datasets. This chapter discusses a variety of potential research areas, including satellite-based monitoring of urban areas, IoT and cloud computing in urban management, and the use of machine learning in urban environmental research. In addition to digitization, the availability of big data sets, machine learning (ML), and artificial intelligence (AI) will revolutionize the way urban areas are analyzed and planned, opening up new possibilities for sustainable urban challenges. The chapter outlines qualitative and quantitative methods utilizing predictive models and scenario analysis for identifying and implementing urban environmental policies. The recommendations provided in this chapter can be used for further urban studies, research, and the development of smart and resilient cities. © 2024 Elsevier Ltd. All rights reserved.
Electrochemical sensing of dopamine over polyindole-composite electrode
(American Ceramic Society, 2011) Prem C. Pandey; Dheeraj S. Chauhan; S. Kumari
We hereby report a new conducting polymer composite i.e., polyindole-camphorsulphonic acid (PIn-CSA) composite, and its use in the development of dopamine sensor. The processable PIn-CSA composite is developed by homogenizing equimolar ratio of chemically synthesized polyindole and camphor sulphonic acid in tetrahydrofuran. The homogenized PIn-CSA composite is cast over the Pt disc electrode under ambient conditions and assembled in a homemade electrode body equipped with Ag/AgCl reference electrode. The ion sensor exhibits excellent response towards dopamine in presence of ascorbic acid over a wide concentration range. The sensor can be used for 1 month without any major drift in its sensitivity and limit of detection.
Electrochemical synthesis of tetraphenylborate doped polypyrrole and its applications in designing a novel zinc and potassium ion sensor
(Wiley-VCH Verlag, 2002) Prem C. Pandey; Govind Singh; Pramod K. Srivastava
The electrochemical synthesis of tetraphenylborate (TPB) ion doped polypyrrole is reported. The electrochemical polymerization of ion exchanger doped polypyrrole is carried out in dry acetonitrile. The polypyrrole synthesized under present conditions is characterized by scanning electron microscopy and cyclic voltammetry. The applications of new ion exchanger doped polypyrrole in the development of solid-state ion sensors are reported. The ion sensing properties and construction of new conducting polymer based Zn++ ion and potassium ion sensors are described. The Zn++ ion sensor is developed by TPB doped polymer modified electrode itself whereas K+ ion sensor is developed by laying down of another layer of dibenzo-18-crown-6 impregnated plasticized Polyvinylchloride (PVC) matrix membrane. The response curve on Zn++ ion sensing with and without polymer layer is also studied and reported. An effort on selective sensing of Zn++ ion is also made and the data on Ni++, Co++, Pb++, and Mg++ ions are reported using polymer modified electrode. Similarly the effect of Na+ and NH4+ ions on the response of K+ ion sensing is also reported. The contribution of tetraphenylborate in designing these ions sensors are discussed.
Electrochemical synthesis of tetraphenylborate-doped polypyrrole: Dependence of zinc ion sensing on the polymeric microstructure
(2002) Prem C. Pandey; Govind Singh
The electrochemical synthesis of tetraphenylborate (TPB) ion-doped polypyrrole is reported. The polymerization of ion exchanger-doped polypyrrole was carried out in dry acetonitrile by both potentiodynamic and potentiostatic modes of electropolymerization. The polymers formed under these two conditions were characterized by scanning electron microscopy and cyclic voltammetry. The polymeric microstructure was found to be dependent on the mode of electropolymerization. The TPB-doped polymer-modified electrode was sensitive to zinc ion. The zinc ion sensing was found to be dependent on the polymeric microstructure. The response curves on Zn2+ ion sensing of polymer-modified electrode with variation in polymeric microstructure were investigated. The effort on selective sensing of Zn2+ ion was also made and the data on Ni2+, Co2+, Pb2+ and Mg2+ ions are reported using polymer-modified electrode. The contribution of TPB in designing these ions sensors was discussed. © 2002 Elsevier Science B.V. All rights reserved.
Exploring aquatic environments through geographical information science: A comprehensive review and applications
(Elsevier, 2024) Smrutisikha Mohanty; Md Wasim; Prem C. Pandey; Prashant K. Srivastava
In recent years, environmental monitoring become a topic of discussion due to the rapid increase in anthropogenic activities and natural calamities. Monitoring is important to assess the environmental condition and maintains the ecological balance at regional and global levels. The present study focuses on the role of geographical information system (GIS) in water resource and coastal environment monitoring. GIS techniques have proved to be an effective tool for monitoring, analyzing, and mapping the various aspects related to environmental issues such as ground water potential mapping, flood risk assessment, water quality assessment, shoreline changes, coastal geomorphological and habitat mapping. GIS-based fuzzy, analytical hierarchy process (AHP), frequency ratio (FR), weighted overly (WO), spatial interpolation methods, machine learning, and artificial neural network (ANN) are widely used by researchers to prepare a decision system for environmental management. In future, the integration of GIS software with statistical methods may help to analyze the spatiotemporal data at broader level, thus enabling the researchers to produce more precise outcome. © 2024 Elsevier Inc. All rights reserved.
Geo-information for disaster monitoring and management
(Springer International Publishing, 2024) Prem C. Pandey; Rajesh Kumar; Manish Pandey; Gregory Giuliani; R.K. Sharma; Prashant K. Srivastava
The objective of this publication is to provide insight into advancing remote sensing techniques dealing with floods, droughts, landslides, earthquakes, permafrost-related hazards, glacial lake outburst floods, forest fires, droughts, tropical cyclones, climate resilience and COVID-19. This publication will incorporate the latest technologies and techniques to illustrate disaster monitoring for acquiring information and dissemination of technological results and outcomes for the betterment of society. This publication would be of immense importance for earth scientists, policymakers and professionals working in the field of disaster risk reduction. © Springer Nature Switzerland AG 2024. All rights reserved.
GIS and remote sensing aided information for soil moisture estimation: A comparative study of interpolation techniques
(MDPI AG, 2019) Prashant K. Srivastava; Prem C. Pandey; George P. Petropoulos; Nektarios N. Kourgialas; Varsha Pandey; Ujjwal Singh
Soil moisture represents a vital component of the ecosystem, sustaining life-supporting activities at micro and mega scales. It is a highly required parameter that may vary significantly both spatially and temporally. Due to this fact, its estimation is challenging and often hard to obtain especially over large, heterogeneous surfaces. This study aimed at comparing the performance of four widely used interpolation methods in estimating soil moisture using GPS-aided information and remote sensing. The DistanceWeighting (IDW), Spline, Ordinary Kriging models and Kriging with External Drift (KED) interpolation techniques were employed to estimate soil moisture using 82 soil moisture field-measured values. Of those measurements, data from 54 soil moisture locations were used for calibration and the remaining data for validation purposes. The study area selected was Varanasi City, India covering an area of 1535 km2. The soil moisture distribution results demonstrate the lowest RMSE (root mean square error, 8.69%) for KED, in comparison to the other approaches. For KED, the soil organic carbon information was incorporated as a secondary variable. The study results contribute towards efforts to overcome the issue of scarcity of soil moisture information at local and regional scales. It also provides an understandable method to generate and produce reliable spatial continuous datasets of this parameter, demonstrating the added value of geospatial analysis techniques for this purpose. © 2019 by the authors.
Molecular weight of polyethylenimine-dependent transfusion and selective antimicrobial activity of functional silver nanoparticles
(Cambridge University Press, 2020) Atul Kumar Tiwari; Munesh Kumar Gupta; Govind Pandey; Roger J. Narayan; Prem C. Pandey
Synthetic cationic polymer-mediated synthesis of silver nanoparticles and selective antimicrobial activity of the same were demonstrated. Polyethyleneimine (PEI)-coated silver nanoparticles showed antimicrobial activity against Acinetobacter baumannii as a function of the polymeric molecular weight (MW) of PEI. Silver nanoparticles were coated with PEI of three different MWs: Ag-NP-1 with PEI exhibiting a MW of 750,000, Ag-NP-2 with PEI exhibiting a MW of 1300, and Ag-NP-3 with PEI exhibiting a MW of 60,000. These nanoparticles showed a particle size distribution of 4-20 nm. The nanoparticles exhibited potent antimicrobial activity against A. baumannii, with the minimum inhibitory concentration of Ag-NP-1, Ag-NP-2, and Ag-NP-3 on the order of 5, 10, and 5 μg/mL, respectively, and minimum bactericidal concentration of Ag-NP-1, Ag-NP-2, and Ag-NP-3 on the order of 10, 20, and 10 μg/mL, respectively. Fluorescence imaging of Ag-NPs revealed selective transfusion of Ag-NPs across the cell membrane as a function of the polymeric MW; differential interaction of the cytoplasmic proteins during antimicrobial activity was observed. Copyright © Materials Research Society 2020.
Molecular Weights of Polyethyleneimine-Dependent Physicochemical Tuning of Gold Nanoparticles and FRET-Based Turn-On Sensing of Polymyxin B
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Atul Kumar Tiwari; Munesh Kumar Gupta; Ramovatar Meena; Prem C. Pandey; Roger J. Narayan
Environmental monitoring and the detection of antibiotic contaminants require expensive and time-consuming techniques. To overcome these challenges, gold nanoparticle-mediated fluorometric “turn-on” detection of Polymyxin B (PMB) in an aqueous medium was undertaken. The molecular weight of polyethyleneimine (PEI)-dependent physicochemical tuning of gold nanoparticles (PEI@AuNPs) was achieved and employed for the same. The three variable molecular weights of branched polyethyleneimine (MW 750, 60, and 1.3 kDa) molecules controlled the nano-geometry of the gold nanoparticles along with enhanced stabilization at room temperature. The synthesized gold nanoparticles were characterized through various advanced techniques. The results revealed that polyethyleneimine-stabilized gold nanoparticles (PEI@AuNP-1-3) were 4.5, 7.0, and 52.5 nm in size with spherical shapes, and the zeta potential values were 29.9, 22.5, and 16.6 mV, respectively. Accordingly, the PEI@AuNPs probes demonstrated high sensitivity and selectivity, with a linear relationship curve over a concentration range of 1–6 μM for polymyxin B. The limit of detection (LOD) was calculated as 8.5 nM. This is the first unique report of gold nanoparticle nano-geometry-dependent FRET-based turn-on detection of PMB in an aqueous medium. We believe that this approach would offer a complementary strategy for the development of a highly sophisticated and advanced sensing system for PMB and act as a template for the development of new nanomaterial-based engineered sensors for rapid antibiotic detection in environmental as well as biological samples. © 2024 by the authors.