Single gold nanoplasmonic sensor for clinical cancer diagnosis based on specific interaction between nucleic acids and protein

Evaluation of DNA-protein complex structures using the deep learning method

Biological processes such as transcription, repair, and regulation require interactions between DNA and proteins. To unravel their functions, it is imperative to determine the high-resolution structures of DNA-protein complexes. However, experimental methods for this purpose are costly and technically demanding. Consequently, there is an urgent need for computational techniques to identify the structures of DNA-protein complexes. Despite technological advancements, accurately identifying DNA-protein complexes through computational methods still poses a challenge. Our team has developed a cutting-edge deep-learning approach called DDPScore that assesses DNA-protein complex structures. DDPScore utilizes a 4D convolutional neural network to overcome limited training data. This approach effectively captures local and global features while comprehensively considering the conformational changes arising from the flexibility during the DNA-protein docking process. DDPScore consistently outperformed the available methods in comprehensive DNA-protein complex docking evaluations, even for the flexible docking challenges. DDPScore has a wide range of applications in predicting and designing structures of DNA-protein complexes.

Nanoplasmonic biosensors for precision medicine

Nanoplasmonic biosensors have a huge boost for precision medicine, which allows doctors to better understand diseases at the molecular level and to improve the earlier diagnosis and develop treatment programs. Unlike traditional biosensors, nanoplasmonic biosensors meet the global health industry's need for low-cost, rapid and portable aspects, while offering multiplexing, high sensitivity and real-time detection. In this review, we describe the common detection schemes used based on localized plasmon resonance (LSPR) and highlight three sensing classes based on LSPR. Then, we present the recent applications of nanoplasmonic in other sensing methods such as isothermal amplification, CRISPR/Cas systems, lab on a chip and enzyme-linked immunosorbent assay. The advantages of nanoplasmonic-based integrated sensing for multiple methods are discussed. Finally, we review the current applications of nanoplasmonic biosensors in precision medicine, such as DNA mutation, vaccine evaluation and drug delivery. The obstacles faced by nanoplasmonic biosensors and the current countermeasures are discussed.

Structural predictions of protein-DNA binding: MELD-DNA

Structural, regulatory and enzymatic proteins interact with DNA to maintain a healthy and functional genome. Yet, our structural understanding of how proteins interact with DNA is limited. We present MELD-DNA, a novel computational approach to predict the structures of protein-DNA complexes. The method combines molecular dynamics simulations with general knowledge or experimental information through Bayesian inference. The physical model is sensitive to sequence-dependent properties and conformational changes required for binding, while information accelerates sampling of bound conformations. MELD-DNA can: (i) sample multiple binding modes; (ii) identify the preferred binding mode from the ensembles; and (iii) provide qualitative binding preferences between DNA sequences. We first assess performance on a dataset of 15 protein-DNA complexes and compare it with state-of-the-art methodologies. Furthermore, for three selected complexes, we show sequence dependence effects of binding in MELD predictions. We expect that the results presented herein, together with the freely available software, will impact structural biology (by complementing DNA structural databases) and molecular recognition (by bringing new insights into aspects governing protein-DNA interactions).

Directivity-Enhanced Detection of a Single Nanoparticle Using a Plasmonic Slot Antenna

In situ refractive index sensors integrated with nanoaperture-based optical tweezers possess stable and sensitive responsivity to single nanoparticles. In most existing works, detection events are only identified using the total light intensity with directivity information ignored, leading to a low signal-to-noise ratio. Here, we propose to detect an optically trapped 20 nm silica particle by monitoring directivity of a plasmonic antenna. The main and secondary radiation lobes of the antenna reverse upon trapping because the particle-induced perturbation negates the relative phase between two antenna elements, leading to a significant change of the antenna front-to-back ratio. As a result, we obtain a signal-to-noise ratio of 20, with an order-of-magnitude improvement as compared to the intensity-only detection scheme.

Plasmonic Nanoparticle Conjugation for Nucleic Acid Biosensing

This chapter details the use of gold nanorods conjugated with peptide nucleic acid probes for sequence-specific detection of circulating tumor DNA (ctDNA). ctDNA is gaining increased attention as a biomarker for liquid biopsy, the process of detecting molecules in the peripheral blood rather than a tissue sample. It has wide ranging applications as a diagnostic and prognostic biomarker with a similar mutational profile as the tumor. Plasmonic nanoparticles offer a relatively rapid, amplification-free method for detection of ctDNA through the use of sequence-specific peptide nucleic acid (PNA) probes. In this chapter, we discuss methods for probe design, conjugation to plasmonic particles, and ctDNA quantitation with the resulting sensor. This chapter is a resource for those looking to use plasmonic gold particles for sensing in a solution format for a range of applications.

Rational design of on-chip gold plasmonic nanoparticles towards ctDNA screening

This paper demonstrates the design, synthesis, simulation, and testing of three distinct geometries of plasmonic gold nanoparticles for on-chip DNA screening towards liquid biopsy. By employing a seed-mediated growth method, we have synthesized gold nanospheres, nanorods, and nanobipyramids. In parallel, we developed numerical simulations to understand the effects of nanoparticle geometry on the resonance features and refractive index sensitivity. Both experimental and simulation results were compared through a series of studies including in-solution and on-chip tests. We have thoroughly characterized the impact of nanoparticle geometry on the sensitivity to circulating tumor DNA, with immediate implications for liquid biopsy. The results agree well with theoretical predictions and simulations, including both bulk refractive index sensitivity and thin film sensitivity. Importantly, this work quantitatively establishes the link between nanoparticle geometry and efficacy in detecting rare circulating biomarkers. The nanobipyramids provided the highest sensitivity, approximately doubling the sensitivity compared to nanorods. To the best of our knowledge this is the first report carrying through geometric effects of simulation to clinically relevant biosensing. We put forth here synthesis and testing of three nanoparticle geometries, and a framework for both experimental and theoretical validation of plasmonic sensitivities towards liquid biopsy.

Single plasmonic nanostructures for biomedical diagnosis

The field of single nanoparticle plasmonics has grown enormously. There is no doubt that a wide diversity of the nanoplasmonic techniques and nanostructures represents a tremendous opportunity for fundamental biomedical studies as well as sensing and imaging applications. Single nanoparticle plasmonic biosensors are efficient in label-free single-molecule detection, as well as in monitoring real-time binding events of even several biomolecules. In the present review, we have discussed the prominent advantages and advances in single particle characterization and synthesis as well as new insight into and information on biomedical diagnosis uniquely obtained using single particle approaches. The approaches include the fundamental studies of nanoplasmonic behavior, two typical methods based on refractive index change and characteristic light intensity change, exciting innovations of synthetic strategies for new plasmonic nanostructures, and practical applications using single particle sensing, imaging, and tracking. The basic sphere and rod nanostructures are the focus of extensive investigations in biomedicine, while they can be programmed into algorithmic assemblies for novel plasmonic diagnosis. Design of single nanoparticles for the detection of single biomolecules will have far-reaching consequences in biomedical diagnosis.

MutS protein-based fiber optic particle plasmon resonance biosensor for detecting single nucleotide polymorphisms

A new biosensing method is presented to detect gene mutation by integrating the MutS protein from bacteria with a fiber optic particle plasmon resonance (FOPPR) sensing system. In this method, the MutS protein is conjugated with gold nanoparticles (AuNPs) deposited on an optical fiber core surface. The target double-stranded DNA containing an A and C mismatched base pair in a sample can be captured by the MutS protein, causing increased absorption of green light launching into the fiber and hence a decrease in transmitted light intensity through the fiber. As the signal change is enhanced through consecutive total internal reflections along the fiber, the limit of detection for an AC mismatch heteroduplex DNA can be as low as 0.49 nM. Because a microfluidic chip is used to contain the optical fiber, the narrow channel width allows an analysis time as short as 15 min. Furthermore, the label-free and real-time nature of the FOPPR sensing system enables determination of binding affinity and kinetics between MutS and single-base mismatched DNA. The method has been validated using a heterozygous PCR sample from a patient to determine the allelic fraction. The obtained allelic fraction of 0.474 reasonably agrees with the expected allelic fraction of 0.5. Therefore, the MutS-functionalized FOPPR sensor may potentially provide a convenient quantitative tool to detect single nucleotide polymorphisms in biological samples with a short analysis time at the point-of-care sites.

Thermal Atomic Layer Deposition of Gold: Mechanistic Insights, Nucleation, and Epitaxy

An in situ microbalance and infrared spectroscopic study of alternating exposures to Me₂Au(S₂CNEt₂) and ozone illuminates the organometallic chemistry that allows for the thermal atomic layer deposition (ALD) of gold. In situ quartz crystal microbalance (QCM) studies resolve the nucleation delay and island growth of Au on a freshly prepared aluminum oxide surface with single cycle resolution, revealing inhibition for 40 cycles prior to slow nucleation and film coalescence that extends over 300 cycles. In situ infrared spectroscopy informed by first-principles computation provides insight into the surface chemistry of the self-limiting half-reactions, which are consistent with an oxidized Au surface mechanism. X-ray diffraction of ALD-grown gold on silicon, silica, sapphire, and mica reveals consistent out-of-plane oriented crystalline film growth as well as epitaxially directed in-plane orientation on closely lattice-matched mica at a relatively low growth temperature of 180 °C. A more complete understanding of ALD gold nucleation, surface chemistry, and epitaxy will inform the next generation of low-temperature, nanoscale, textured depositions that are applicable to high surface area supports.

Carbohydrate-protein template synthesized high mannose loading gold nanoclusters: A powerful fluorescence probe for sensitive Concanavalin A detection and specific breast cancer cell imaging

Protein-encapsulated gold nanoclusters (Au NCs) have recently gained much attention in biosensing and bioimaging applications owing to their remarkable fluorescence properties, nontoxicity and good biocompatibility. In this work, the mannose was grafted onto the bovine serum albumin (BSA) encapsulated Au NCs (BSA-Au NCs) to produce a mannose functionalized BSA-Au NCs (Man-BSA-Au NCs) as a new fluorescence probe for Concanavalin A (Con A) detection and human breast cancer cell imaging. A new strategy with mannose-BSA conjugates as template was firstly applied for the synthesis of Man-BSA-Au NCs, leading to a high loading of mannose (767.6 ± 7.2 mg/L) onto BSA-Au NCs. The as-prepared Man-BSA-Au NCs showed advantages of facile preparation, good monodispersity and strong red-emission. Notably, aggregation-induced fluorescence quenching of Man-BSA-Au NCs was triggered by Con A due to the multivalent cooperative interactions between mannose and Con A, which was subsequently confirmed by MALDI-TOF MS. Hence highly selective and sensitive fluorescence detection of Con A was achieved by using Man-BSA-Au NCs as a fluorescence sensor. A good linear relationship was obtained over the range of 0.01-1 μM (R² = 0.994) with a detection limit of 0.62 nM (S/N = 3). The developed sensor was then applied to determine Con A in human serum with acceptable recoveries of 93.70-104.8%. Moreover, based on the specific recognition between mannose and overexpressed mannose receptors on human breast cancer cells, the Man-BSA-Au NCs were successfully utilized for cancer cell imaging with good specificity.

Real-time and label-free detection of VKORC1 genes based on a magnetoelastic biosensor for warfarin therapy

Various thrombotic disorders have been treated with the anticoagulant warfarin. However, a small change in warfarin concentration may lead to drug adverse reactions or therapeutic failure due to its narrow therapeutic index. Therefore, the dose of warfarin must be monitored for each patient during therapy in real-time and in a sensitive and stable manner. In this work, we designed a magnetoelastic (ME) biosensor using Metglas alloy 2826 to detect VKORC1 genotypes, which is one of the most important known genetic determinants of warfarin dosing. The sensor enabled both fast responses to DNA binding and wireless transmission of signals. Specifically in the target recognition layer, the sensor introduced an avidin-biotin interaction system for signal amplification by increasing the surface load mass. The resonance frequency shift of the signal was linear to the concentration of the target in the range of 0.1 fM to 10 pM, with a detection limit (LOD) of 0.00389 fM (S/N = 3) and a sensitivity of 45.7 Hz pM^-1. Importantly, this ME-based biosensor was small and portable without the use of any optical labels, which has high potential to be applied in advanced biomedical diagnosis of nucleic acids and proteins.

Using gold nanoparticles to detect single-nucleotide polymorphisms: toward liquid biopsy

The possibility of detecting genetic mutations rapidly in physiological media through liquid biopsy has attracted the attention within the materials science community. The physical properties of nanoparticles combined with robust transduction methods ensure an improved sensitivity and specificity of a given assay and its implementation into point-of-care devices for common use. Covering the last twenty years, this review gives an overview of the state-of-the-art of the research on the use of gold nanoparticles in the development of colorimetric biosensors for the detection of single-nucleotide polymorphism as cancer biomarker. We discuss the main mechanisms of the assays that either are assisted by DNA-based molecular machines or by enzymatic reactions, summarize their performance and provide an outlook towards future developments.

Biochar combined with montmorillonite amendments increase bioavailable organic nitrogen and reduce nitrogen loss during composting

This study aimed to compare the effects of biochar, montmorillonite and their mixture on nitrogen availability and nitrogen loss during chicken manure composting. Four lab-scale composting experiments, the control (CK), 5% biochar addition (BC), 5% montmorillonite addition (M) and 2.5% biochar + 2.5% montmorillonite addition (BCM), were established. Results showed that the addition of BC, M and BCM significantly improved the contents of bioavailable organic nitrogen and NH₄⁺-N in composts. In addition, BC and BCM reduced N loss by 19.2% and 12.2%, respectively, in comparison with CK. Significant shift of key bacterial communities associated with N transformation were also found in four treatments. Redundancy analysis and structural equation models indicated different additives changed the correlation among bacterial communities, environmental factors and organic N fractions. Comparison of N availability and N loss indicated that the combination of biochar and montmorillonite are more effective than that of separate application during composting.

Targeted Detection of Single-Nucleotide Variations: Progress and Promise

Advances in nucleic acid sequencing and genotyping technologies have facilitated the discovery of an increasing number of single-nucleotide variations (SNVs) associated with disease onset, progression, and response to therapy. The reliable detection of such disease-specific SNVs can ensure timely and effective therapeutic action, enabling precision medicine. This has driven extensive efforts in recent years to develop novel methods for the fast and cost-effective analysis of targeted SNVs. In this Review, we highlight the most recent and significant advances made toward the development of such methodologies.

Single gold-bridged nanoprobes for identification of single point DNA mutations

Consensus ranking of protein affinity to identify point mutations has not been established. Therefore, analytical techniques that can detect subtle variations without interfering with native biomolecular interactions are required. Here we report a rapid method to identify point mutations by a single nanoparticle sensing system. DNA-directed gold crystallization forms rod-like nanoparticles with bridges based on structural design. The nanoparticles enhance Rayleigh light scattering, achieving high refractive-index sensitivity, and enable the system to monitor even a small number of protein-DNA binding events without interference. Analysis of the binding affinity can compile an atlas to distinguish the potential of various point mutations recognized by MutS protein. We use the atlas to analyze the presence and type of single point mutations in BRCA1 from samples of human breast and ovarian cancer cell lines. The strategy of synthesis-by-design of plasmonic nanoparticles for sensors enables direct identification of subtle biomolecular binding distortions and genetic alterations.

Strand displacement amplification-coupled dynamic light scattering method to detect urinary telomerase for non-invasive detection of bladder cancer

Despite huge successes achieved by strand displacement amplification (SDA) and gold nanoparticles (AuNPs) in biomolecules sensing, the strategy of combination of SDA and AuNPs-based dynamic light scattering (DLS) for a biomolecule sensing is unexplored. Here we developed a non-invasive, SDA-based DLS method for the diagnosis of bladder cancer by detecting telomerase activity in human urine. In the presence of telomerase, the telomerase substrate (TS) primer was elongated with repeating sequences of (TTAGGG)n, and the resulting product triggers SDA between the hairpin deoxyribonucleic acid (DNA) and the Primer. The SDA product can be recognized by the oligonucleotide-modified AuNPs probes, resulting in DLS measurable AuNPs aggregation. The assay displayed a detection limit of 3 MCF-7 cells with a signal-to-noise ratio of 3 in a dynamic range of 5-1000 cells. The method was simple, reliable and has been successfully applied in the detection of telomerase in urine with good accuracy, selectivity and reproducibility. Moreover, only urine samples from bladder cancer patients induced a significant change in the average hydrodynamic diameter, indicating practical applicability of the method for the non-invasive diagnosis of bladder cancer.

Design of peptide nucleic acid probes on plasmonic gold nanorods for detection of circulating tumor DNA point mutations

Here we present a gold nanorod-based platform for the sequence-specific detection of circulating tumor DNA (ctDNA) point mutations without the need for amplification or fluorescence labeling. Peptide nucleic acid probes complimentary to the G12V mutation in the KRAS gene were conjugated to gold nanorods, and the localized surface plasmon resonance absorbance through the sample was measured after exposure to synthetic ctDNA at various concentrations. Each step of the reaction was thoroughly controlled, starting from reagent concentrations and including conjugation, sonication, and incubation time. The platform was evaluated in both buffer and spiked healthy patient serum, demonstrating a linear working range below 125 nanograms of ctDNA per milliliter solution, and an effective limit of detection of 2 nanograms of ctDNA per milliliter. A clear distinction between mutant and wild type synthetic ctDNA was also found using this platform. In order to improve upon the selectivity of the sensor, a DNA hybridization simulation was performed to understand how the addition of mutations to the peptide nucleic acid probe could enhance the selectivity for capture of mutant over wild type sequences. The top candidate from the simulations, which had an additional mutation two base pairs away from the mutation of interest, had a significant impact on the selectivity between mutant and wild type capture. This paper provides a framework for sequence-specific capture of ctDNA, and a method of improving selectivity for desired point mutations through careful probe design.

High-Quality Ultrathin Gold Layers with an APTMS Adhesion for Optimal Performance of Surface Plasmon Polariton-Based Devices

A low-absorption adhesion layer plays a crucial role for both localized and propagating surface plasmons when ultrathin gold is used. To date, the most popular adhesion layers are metallic, namely, Cr and Ti. However, to the best of our knowledge, the influence of these adhesion layers on the behavior of propagating plasmon modes has not been thoroughly investigated nor reported in the literature. It is therefore important to study the effect of these few- to several-nanometers-thick adhesion layers on the propagating plasmons because it may affect the performance of plasmonic devices, in particular, when the Au layer is not much thicker than the adhesion layers. We experimentally compared the performances of the ultrathin gold films to show the pivotal influence of adhesion layers on highly confined propagating plasmonic modes, using Cr and 3-aminopropyl trimethoxysilane (APTMS) adhesion layers and without any adhesion layer. We show that the gold films with the APTMS adhesion layer have the lowest surface roughness and the short-range surface plasmon polaritons supported on the Au surface exhibit properties close to the theoretical calculations, considering an ideal gold film.

Recent advances in biosensor development for the detection of cancer biomarkers

Cancer is the second largest disease throughout the world with an increasing mortality rate over the past few years. The patient's survival rate is uncertain due to the limitations of cancer diagnosis and therapy. Early diagnosis of cancer is decisive for its successful treatment. A biomarker-based cancer diagnosis may significantly improve the early diagnosis and subsequent treatment. Biosensors play a crucial role in the detection of biomarkers as they are easy to use, portable, and can do analysis in real time. This review describes various biosensors designed for detecting nucleic acid and protein-based cancer biomarkers for cancer diagnosis. It mainly lays emphasis on different approaches to use electrochemical, optical, and mass-based transduction systems in cancer biomarker detection. It also highlights the analytical performances of various biosensor designs concerning cancer biomarkers in detail.

Gold nanocrystals with DNA-directed morphologies

Precise control over the structure of metal nanomaterials is important for developing advanced nanobiotechnology. Assembly methods of nanoparticles into structured blocks have been widely demonstrated recently. However, synthesis of nanocrystals with controlled, three-dimensional structures remains challenging. Here we show a directed crystallization of gold by a single DNA molecular regulator in a sequence-independent manner and its applications in three-dimensional topological controls of crystalline nanostructures. We anchor DNA onto gold nanoseed with various alignments to form gold nanocrystals with defined topologies. Some topologies are asymmetric including pushpin-, star- and biconcave disk-like structures, as well as more complex jellyfish- and flower-like structures. The approach of employing DNA enables the solution-based synthesis of nanocrystals with controlled, three-dimensional structures in a desired direction, and expands the current tools available for designing and synthesizing feature-rich nanomaterials for future translational biotechnology.

Bottom-up synthesis of colloidal metallic nanomaterials with a designable structure is challenging. Here, the authors report the directed crystallisation of gold by a single DNA molecular regulator, using it to synthesise gold nanocrystals with defined complex morphologies.

Tracking of STAT3 signaling for anticancer drug-discovery based on localized surface plasmon resonance

The label-free sensor, based on the LSPR shift response by tracking of the STAT3 signaling pathways, is an ultrasensitive for drug screening of anticancer therapy.

Gold-Coated Superparamagnetic Nanoparticles for Single Methyl Discrimination in DNA Aptamers

Au- and iron-based magnetic nanoparticles (NPs) are promising NPs for biomedical applications due to their unique properties. The combination of a gold coating over a magnetic core puts together the benefits from adding the magnetic properties to the robust chemistry provided by the thiol functionalization of gold. Here, the use of Au-coated magnetic NPs for molecular detection of a single methylation in DNA aptamer is described. Binding of α-thrombin to two aptamers conjugated to these NPs causes aggregation, a phenomenon that can be observed by UV, DLS and MRI. These techniques discriminate a single methylation in one of the aptamers, preventing aggregation due to the inability of α-thrombin to recognize it. A parallel study with gold and ferromagnetic NPs is detailed, concluding that the Au coating of FexOy NP does not affect their performance and that they are suitable as complex biosensors. These results prove the high detection potency of Au-coated SPIONs for biomedical applications especially for DNA repair detection.

Measurement of the light scattering of single micrometer-sized particles captured with a microfluidic trap

Light scattering detection of a single particle is significant to both theoretical developments and application progresses of particle scattering. In this work, a new method employing the polydimethylsiloxane microfluidic catcher with self-regulation was developed to detect the light scattering of an individual micro particle (20.42, 23.75, and 31.10 μm) in a wide angular range. This system can rapidly (<2 min) immobilize single particles without aggregations and continuously analyze its light scattering ranging from 2° to 162°. The high success ratio of the capture, good agreement with the anticipation, and moderate time and cost make this method a promising candidate in single-particle-scattering applications.

Single nanoparticle plasmonic sensors

The adoption of plasmonic nanomaterials in optical sensors, coupled with the advances in detection techniques, has opened the way for biosensing with single plasmonic particles. Single nanoparticle sensors offer the potential to analyse biochemical interactions at a single-molecule level, thereby allowing us to capture even more information than ensemble measurements. We introduce the concepts behind single nanoparticle sensing and how the localised surface plasmon resonances of these nanoparticles are dependent upon their materials, shape and size. Then we outline the different synthetic approaches, like citrate reduction, seed-mediated and seedless growth, that enable the synthesis of gold and silver nanospheres, nanorods, nanostars, nanoprisms and other nanostructures with tunable sizes. Further, we go into the aspects related to purification and functionalisation of nanoparticles, prior to the fabrication of sensing surfaces. Finally, the recent developments in single nanoparticle detection, spectroscopy and sensing applications are discussed.

Quencher group induced high specificity detection of telomerase in clear and bloody urines by AIEgens

Telomerase is a widely used tumor biomarker for early cancer diagnosis. On the basis of the combined use of aggregation-induced emission (AIE) fluorogens and quencher, a quencher group induced high specificity strategy for detection of telomerase activity from cell extracts and cancer patients' urine specimens was creatively developed. In the absence of telomerase, fluorescence background is extremely low due to the short distance between quencher and AIE dye. In the addition of telomerase, fluorescence enhances significantly. The telomerase activity in the E-J, MCF-7, and HeLa extracts equivalent to 5-10 000 cells can be detected by this method in ∼1 h. Furthermore, the distinguishing of telomerase extracted from 38 cancer and 15 normal urine specimens confirms the reliability and practicality of this protocol. In contrast to our previous results (Anal. Chem. 2015, 87, 6822-6827), these advanced experiments obtain more remarkable specificity.

Label-free detection of ApoE4-mediated β-amyloid aggregation on single nanoparticle uncovering Alzheimer's disease

Beta amyloid (Aβ) deposition is a pathological milestone of Alzheimer's disease (AD). This is facilitated by an isoform of Apolipoprotein E4 (ApoE4), which is a dominant risk factor for AD. However, current in vitro Aβ aggregation assays were performed in extreme conditions not linked to physiological conditions, to understand the mechanism of Aβ induced neurotoxicity. Here, we present a simple method for the ApoE4-mediated Aβ aggregation at physiological conditions using single gold nanoparticle based on localized surface plasmon resonance (LSPR). It can be directly observed by dark-field microscope or even by the naked eye. Following LSPR principles, we used ApoE4 inducing Aβ42 self-assemblies on gold nanoparticles (AuNPs) surface via their surface charge interaction. Using physiologically mimic cerebrospinal fluid, we determined a detection limit of 1.5 pM for Aβ42 corresponding to the ~2.9 nm LSPR-peak shift under ApoE4. Interestingly, the result also shows that ApoE4 induces the aggregation of Aβ42 more specifically and rapidly than that of Aβ40. This is the first biomimetic platform for real-time detection of Aβ aggregation, mimicking biological conditions, which can be used to investigate AD directly.