scholarly journals Randomly positioned gold nanoparticles as fluorescence enhancers in apta-immunosensor for malaria test

2021 ◽  
Vol 188 (3) ◽  
Author(s):  
Antonio Minopoli ◽  
Bartolomeo Della Ventura ◽  
Raffaele Campanile ◽  
Julian A. Tanner ◽  
Andreas Offenhäusser ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Self Assembly ◽  
Whole Blood ◽  
Sample Pretreatment ◽  
High Specificity ◽  
Enhanced Fluorescence ◽  
High Throughput Analysis ◽  
New Approach ◽  
Fluorescence Amplification

AbstractA plasmon-enhanced fluorescence-based antibody-aptamer biosensor — consisting of gold nanoparticles randomly immobilized onto a glass substrate via electrostatic self-assembly — is described for specific detection of proteins in whole blood. Analyte recognition is realized through a sandwich scheme with a capture bioreceptor layer of antibodies — covalently immobilized onto the gold nanoparticle surface in upright orientation and close-packed configuration by photochemical immobilization technique (PIT) — and a top bioreceptor layer of fluorescently labelled aptamers. Such a sandwich configuration warrants not only extremely high specificity, but also an ideal fluorophore-nanostructure distance (approximately 10–15 nm) for achieving strong fluorescence amplification. For a specific application, we tested the biosensor performance in a case study for the detection of malaria-related marker Plasmodium falciparum lactate dehydrogenase (PfLDH). The proposed biosensor can specifically detect PfLDH in spiked whole blood down to 10 pM (0.3 ng/mL) without any sample pretreatment. The combination of simple and scalable fabrication, potentially high-throughput analysis, and excellent sensing performance provides a new approach to biosensing with significant advantages compared to conventional fluorescence immunoassays. Graphical abstract

scholarly journals Ultrasensitive antibody-aptamer plasmonic biosensor for malaria biomarker detection in whole blood

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Antonio Minopoli ◽  
Bartolomeo Della Ventura ◽  
Bohdan Lenyk ◽  
Francesco Gentile ◽  
Julian A. Tanner ◽  
...  
Keyword(s):  
Whole Blood ◽  
Limit Of Detection ◽  
Sample Pretreatment ◽  
High Specificity ◽  
Ease Of Use ◽  
Enhanced Fluorescence ◽  
High Throughput Analysis ◽  
Malaria Rapid Diagnostic Tests ◽  
Copolymer Micelle ◽  
Very High

AbstractDevelopment of plasmonic biosensors combining reliability and ease of use is still a challenge. Gold nanoparticle arrays made by block copolymer micelle nanolithography (BCMN) stand out for their scalability, cost-effectiveness and tunable plasmonic properties, making them ideal substrates for fluorescence enhancement. Here, we describe a plasmon-enhanced fluorescence immunosensor for the specific and ultrasensitive detection of Plasmodium falciparum lactate dehydrogenase (PfLDH)—a malaria marker—in whole blood. Analyte recognition is realized by oriented antibodies immobilized in a close-packed configuration via the photochemical immobilization technique (PIT), with a top bioreceptor of nucleic acid aptamers recognizing a different surface of PfLDH in a sandwich conformation. The combination of BCMN and PIT enabled maximum control over the nanoparticle size and lattice constant as well as the distance of the fluorophore from the sensing surface. The device achieved a limit of detection smaller than 1 pg/mL (<30 fM) with very high specificity without any sample pretreatment. This limit of detection is several orders of magnitude lower than that found in malaria rapid diagnostic tests or even commercial ELISA kits. Thanks to its overall dimensions, ease of use and high-throughput analysis, the device can be used as a substrate in automated multi-well plate readers and improve the efficiency of conventional fluorescence immunoassays.

Factors Affecting Molecular Self-Assembly and Its Mechanism

2012 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Hueyling Tan
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Polymer Science ◽  
New Approach ◽  
Factors Affecting ◽  
Dna Structures ◽  
Self Assembling ◽  
Wide Range

Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use ofpeptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study ofbiological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries ofexisting disciplines. Many self-assembling systems are rangefrom bi- andtri-block copolymers to DNA structures as well as simple and complex proteins andpeptides. The ultimate goal is to harness molecular self-assembly such that design andcontrol ofbottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes oflife and non-life science applications. Such aspirations can be achievedthrough understanding thefundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.

Bottom-up Evolution from Disks to High-Genus Polymersomes

2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Chain Entanglement ◽  
Bottom Up ◽  
New Approach ◽  
High Genus ◽  
Transmission Electron ◽  
Minimal Radius ◽  
Stop Flow

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>

Bottom-up Evolution from Disks to High-Genus Polymersomes

2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Chain Entanglement ◽  
Bottom Up ◽  
New Approach ◽  
High Genus ◽  
Transmission Electron ◽  
Minimal Radius ◽  
Stop Flow

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>

Benefit Corporations Approach to Environmental, Social and Governance Disclosure: A Focus on Italy

2020 ◽  
Vol 10 (4) ◽  
Author(s):  
Mauro Sciarelli ◽  
Silvia Cosimato ◽  
Giovanni Landi
Keyword(s):  
Qualitative Method ◽  
Positive Impact ◽  
Corporate Structure ◽  
New Approach ◽  
For Profit ◽  
Benefit Corporation ◽  
Benefit Corporations ◽  
Multiple Case ◽  
Governance Disclosure

AbstractOver the last decades, Benefit Corporations arouse as a new corporate structure, alternative to traditional ones and pointing to offer a new approach to the management of business and sustainability issues. These companies' activities are statutory aimed at bridging for-profit and no-profit activities; thus, they intentionally and statutory pursue economic purposes together with social and environmental ones, to create a positive impact on economy, society and environment. Even though, Italian and other national laws set some specific disclosure duties for Benefit Corporations, especially in terms of Environmental, Social and Governance (ESG) issues, the literature still calls for further research on the topic. Therefore, this paper is aimed at contributing to bridge this gap, investigating the way Italian Benefit Corporations approach ESG disclosure. To this end, an exploratory analysis has been conducted, implementing a qualitative method, based on a multiple case study strategy. Even though the descriptive nature of the study, the achieved findings pointed out that the Benefit Corporation structure not necessarily implies a better approach to ESG.

Fluorescence biosensor for Salmonella typhimurium detection in food based on nano-self-assembly of alendronic acid modified upconversion and gold nanoparticles

2021 ◽  
Author(s):  
Min Chen ◽  
Leiqing Pan ◽  
K. Tu
Keyword(s):  
Gold Nanoparticles ◽  
Salmonella Typhimurium ◽  
Gold Nanoparticle ◽  
Alendronic Acid ◽  
Self Assembly ◽  
Upconversion Nanoparticles ◽  
Fluorescent Biosensor ◽  
Fluorescence Biosensor

A simple and quick responsive fluorescent biosensor for Salmonella typhimurium detection based on the recognition of aptamer coupled with alendronic acid (ADA)@upconversion nanoparticles (UCNPs) and gold nanoparticle (AuNPs) has been...

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