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This manuscript aims at raising the attention of the scientific community to the need for better characterised bioreceptors for fast development of point-of-care diagnostic devices able to support mass frequency testing. Particularly, we present the difficulties encountered in finding suitable antibodies for the development of a lateral flow assay for detecting the nucleoprotein of SARS-CoV-2.

Lateral-flow assays (LFAs) are quick, simple and cheap assays to analyze various samples at the point of care or in the field, making them one of the most widespread biosensors currently available. They have been successfully employed for the detection of a myriad of different targets (ranging from atoms up to whole cells) in all type of samples (including water, blood, foodstuff and environmental samples). Their operation relies on the capillary flow of the sample throughout a series of sequential pads, each with different functionalities aiming to generate a signal to indicate the absence/presence (and, in some cases, the concentration) of the analyte of interest. To have a user-friendly operation, their development requires the optimization of multiple, interconnected parameters that may overwhelm new developers. In this tutorial, we provide the readers with: (i) the basic knowledge to understand the principles governing an LFA and to take informed decisions during lateral flow strip design and fabrication, (ii) a roadmap for optimal LFA development independent of the specific application, (iii) a step-by-step example procedure for the assembly and operation of an LF strip for the detection of human IgG and (iv) an extensive troubleshooting section addressing the most frequent issues in designing, assembling and using LFAs. By changing only the receptors, the provided example procedure can easily be adapted for cost-efficient detection of a broad variety of targets.

Novel amphiphilic copolymer nanoparticles (HPAE-co-PLA-DPPE) composed of hyperbranched poly (amine-ester), polylactide and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) segments were designed and synthesized that provided high encapsulation efficiency. These nanoparticles (NPs) were used to encapsulate an antitumor model drug, doxorubicin (DOX). The resulting NPs exhibited high encapsulation efficiency to DOX under an appropriate condition. In vitro release experiments revealed that the release of DOX from NPs was faster at pH 4.5 than that at pH 7.4 or pH 6.0. Confocal microscopy observation indicated that the DOX-loaded NPs can enter cells and localize in lysosomes that can be released quickly into the cytoplasm. The DOX-loaded NPs showed comparable anticancer efficacy with the free drug both in vivo and in vitro. These results demonstrate a feasible application of the hyperbranched copolymer, HPAE-co-PLA-DPPE, as a promising nanocarrier for intracellular delivery of antitumor drugs., From the Clinical Editor: In this paper, the development of novel amphiphilic copolymer nanoparticles is discussed with the goal of establishing high encapsulation efficiency for chemotherapy drugs., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Abstract: Novel amphiphilic copolymer nanoparticles (HPAE-co-PLA-DPPE) composed of hyperbranched poly (amine-ester), polylactide and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) segments were designed and synthesized that provided high encapsulation efficiency. These nanoparticles (NPs) were used to encapsulate an antitumor model drug, doxorubicin (DOX). The resulting NPs exhibited high encapsulation efficiency to DOX under an appropriate condition. In vitro release experiments revealed that the release of DOX from NPs was faster at pH 4.5 than that at pH 7.4 or pH 6.0. Confocal microscopy observation indicated that the DOX-loaded NPs can enter cells and localize in lysosomes that can be released quickly into the cytoplasm. The DOX-loaded NPs showed comparable anticancer efficacy with the free drug both in vivo and in vitro. These results demonstrate a feasible application of the hyperbranched copolymer, HPAE-co-PLA-DPPE, as a promising nanocarrier for intracellular delivery of antitumor drugs. From the Clinical Editor: In this paper, the development of novel amphiphilic copolymer nanoparticles is discussed with the goal of establishing high encapsulation efficiency for chemotherapy drugs. [Copyright &y& Elsevier]

A novel poly( l-aspartic) derivative (PAL-DPPE) containing polylactide and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) segments has been successfully synthesized. The chemical structures of the copolymers were confirmed by Fourier-transform infrared spectroscopy (FTIR), NMR (H NMR, C NMR, P NMR), and thermogravimetric analysis (TGA). Fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) confirmed the formation of micelles of the PAL-DPPE copolymers. In order to estimate the feasibility as novel drug carriers, an anti-tumor model drug doxorubicin (DOX) was incorporated into polymeric micelles by double emulsion and nanoprecipitation method. The DOX-loaded micelle size, size distribution, and encapsulation efficiency (EE) were influenced by the feed weight ratio of the copolymer to DOX. In addition, in vitro release experiments of the DOX-loaded PAL-DPPE micelles exhibited that faster release in pH 5.0 than their release in pH 7.4 buffer. The poly( l-aspartic) derivative copolymer was proved to be an available carrier for the preparation of micelles for anti-tumor drug delivery. [ABSTRACT FROM AUTHOR]

Lateral flow assay (LFA) has been applied in many fields due to its relative ease of use and cost-effectiveness. However, it has low sensitivity and its applications are limited. Probe materials play a significant role in improving the detection efficiency and sensitivity of LFA. In this study, by using concave Pd-Pt nanoparticles as a nanozyme probe, we developed a sensitive LFA based on the sandwich format for qualitative and quantitative detection of Escherichia coli O157:H7. The sensitivity of the LFA was improved by applying the 3,3′,5,5′-tetramethylbenzidine (TMB) substrate onto the test line where the nanozyme was accumulated in the presence of analytes. The nanozyme showed high catalytic performance toward TMB and greatly enhanced the signal intensity of the test line. The sensitivity of the nanozyme-based LFA was 9.0 × 102 cfu/mL in milk, which was 111-fold higher than that of traditional colloidal gold-based LFA. The proposed method has remarkable potential in the detection of various pathogens in real samples. [ABSTRACT FROM AUTHOR]

The relationship between surface structure and anti-fouling mechanism of a new superhydrophobic membrane. [Display omitted] • A novel superhydrophobic membrane based on polydopamine nanoparticles has excellent anti-pollution properties. • The rich layered structure of polydopamine nanoparticle increases the roughness of the membrane surface. • The hydrophobic PDMS layer enhances hydrophobicity of the membrane and immobilizes nanoparticles. • Superhydrophobic membranes exhibit excellent resistance to contamination when treating different types of hypersaline water. Membrane fouling and wetting are significant issues that limit the practical application of vacuum membrane distillation (VMD). In this study, we employed polydopamine nanoparticles (PDANPs) and polydimethylsiloxane (PDMS) to hydrophobically modify pristine polyvinylidene fluoride (PVDF) membranes to improve the overall resistance of the membrane to contamination. The modified membranes have a high contact angle of 162.5° and a low sliding angle (<10°) with excellent superhydrophobic properties. The surface morphology, chemical composition, and stability of the modified superhydrophobic membranes were systematically analyzed. Additionally, the superhydrophobic membranes demonstrated stable flux and excellent salt rejection (99.9%) in a 24 h VMD test in hypersaline and hard water treatment, indicating outstanding anti-wetting and anti-fouling performance. The findings demonstrate that modified membranes have a great potential in long-term VMD practical applications. [ABSTRACT FROM AUTHOR]

The ease of use, low cost and quick operation of lateral flow assays (LFA) have made them some of the most common point of care biosensors in a variety of fields. However, their generally low sensitivity has limited their use for more challenging applications, where the detection of low analytic concentrations is required. Here we propose the use of soluble wax barriers to selectively and temporarily accumulate the target and label nanoparticles on top of the test line (TL). This extended internal incubation step promotes the formation of the immune-complex, generating a 51.7-fold sensitivity enhancement, considering the limit of quantification, and up to 96% signal enhancement compared to the conventional LFA for Human IgG (H-IgG) detection. • Easy-to-use and low-cost strategy for sensitivity enhancement in lateral flow assay. • Dissolvable wax barrier printed for the first time after the test line. • 51.7-fold sensitivity enhancement for Human IgG detection. [ABSTRACT FROM AUTHOR]