Neuroprotective Nanoscavenger Induces Coaggregation of β-Amyloid and Facilitates Its Clearance in Alzheimer’s Disease Brain

Abstract

Open AccessCCS ChemistryRESEARCH ARTICLE1 Aug 2021Neuroprotective Nanoscavenger Induces Coaggregation of β-Amyloid and Facilitates Its Clearance in Alzheimer's Disease Brain Yu Zhao, Yu Jiang, Jingshan Chai, Fan Huang, Zhanzhan Zhang, Qi Liu, Zhuo Yang, Yang Liu and Linqi Shi Yu Zhao Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071 State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 , Yu Jiang State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 Key Laboratory of Bioactive for Materials Ministry of Education, School of Medicine, Nankai University, Tianjin 300071 , Jingshan Chai Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071 State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 , Fan Huang Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300192 , Zhanzhan Zhang Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071 State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 , Qi Liu Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071 State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 , Zhuo Yang State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 Key Laboratory of Bioactive for Materials Ministry of Education, School of Medicine, Nankai University, Tianjin 300071 , Yang Liu *Corresponding author: E-mail Address: [email protected] Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071 State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 and Linqi Shi Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071 State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071 https://doi.org/10.31635/ccschem.020.202000468 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesTrack Citations ShareFacebookTwitterLinked InEmail The accumulation of soluble β-amyloid aggregates (sAβs) is one of the main culprits in Alzheimer's disease (AD) progression, which can lead to synaptic dysfunction and subsequent neurodegeneration. Herein, we describe a nanoscavenger with novel structure that can cross the blood–brain barrier (BBB), accurately collect neurotoxic sAβs, and facilitate amounts of β-amyloid (Aβ) clearance. The nanoscavenger is composed of an Aβ-binding albumin nanoparticle surface-decorated with Immunoglobulin G (IgG) and brain-targeting peptide (PEGylated B6). During transport across the BBB, the nanoscavenger detaches PEGylated B6 and enters the brain. Then, the nanoscavenger competitively inhibits the formation of neurotoxic sAβs, and induces the coaggregation of preexistent sAβs, leading to the formation of nanoscavenger/Aβ coaggregates. Such aggregates are readily cleared by microglia via antibody-dependent cell-mediated phagocytosis (ADCP) even under an inflammatory environment in APP/PS1 mice. Our nanoscavenger demonstrates a strategy to design a synthetic nanostructure to modulate disease-related biological processes, providing a new approach in nanomedicine development. Download figure Download PowerPoint Introduction Alzheimer's disease (AD) is a fatal neurodegenerative disorder characterized by increased amounts of β-amyloid (Aβ) in the central nervous system (CNS).1 Recent works have demonstrated that Aβ dysregulation is intrinsically caused by an overall impairment in Aβ clearance.2–5 Sustained accumulation of Aβ in the brain initiates neuronal damage via toxic Aβ aggregate formation, especially soluble β-amyloid aggregates (sAβs).6–9 Recently, many anti-Aβ nanoagents (e.g., inorganic nanoparticles, polymeric nanoparticles, and carbon nanomaterials) have showed great promise to inhibit the formation of toxic aggregates through strong affinity between nanomaterials and Aβ, which relieves amyloid cytotoxicity.10–14 However, these approaches do not effectively facilitate the clearance of sAβs due to reduced proteolysis in the AD brain, resulting in a disappointing therapeutic effect.3 Therefore, it is crucial to promote the clearance of brain sAβs to mitigate toxicity in the development of effective AD therapy.15 Microglia, the entocranial macrophage, plays an essential role in the removal of aggregated proteins and apoptotic cells.16–18 However, microglia usually does not trigger robust phagocytosis in AD brain showing an inflammatory phenotype.19–22 Recent research shows that proinflammatory cytokines cannot inhibit phagocytosis elicited by antibody-mediated activation of Fc receptors (FcRs), also known as antibody-dependent cell-mediated phagocytosis (ADCP).23,24 Inspired by this, ADCP may provide a potential routine for the effective clearance of Aβ in AD brain. One of the prominent advantages of nanosystems is the ease of constructing custom interfaces or frameworks to specifically modulate protein–protein or protein–cell interactions.25,26 Thus, we have hypothesized that the rational design of an integrated nanostructure for crossing the blood–brain barrier (BBB), accurately inhibiting the formation of sAβs, and accelerating preexistent sAβs clearance in a microglia-dependent manner could be expected to restore Aβ homeostasis in a patient's brain.27 Herein, we demonstrate a nanoscavenger with the goal of efficiently inhibiting the formation of sAβs, collecting preexistent sAβs, and facilitating Aβ clearance in AD brain after systemic administration. The nanoscavenger is composed of a custom Aβ-binding albumin nanoparticle (denoted as NP-GLVFF) in which the surface is functionalized with Immunoglobulin G (IgG) and decorated with PEGylated peptides (polyethylene glycol-CGHKAKGPRK, PEG-B6) for brain targeting. In this design, NP-GLVFF can disturb the formation of neurotoxic sAβs and effectively induce the coaggregation with preexistent sAβs through multivalent interactions (hydrogen bonding) between : Gly-Leu-Val-Phe-Phe (GLVFF) peptide and Aβ.28 IgG can be recognized by the FcRs on microglia to activate ADCP.29 PEG-B6 is able to increase the biocompatibility of nanoscavengers in the bloodstream, and the distal B6 peptide can bind to transferrin receptors to improve the transport efficiency of nanoscavenger crossing the BBB.30 This nanostructure undergoes an acid-responsive cleavage of PEG-B6 during transcytosis across the BBB, leading to the disassembly of nanoscavenger in endosomal microenvironment. As illustrated in Figure 1b, during transport across the BBB, the nanoscavenger detaches the PEG-B6, resulting in exposure of GLVFF and IgG on its surface, and shows strong affinities to sAβs (denoted as NP-GLVFF-IgG). The NP-GLVFF-IgG induces the formation of NP-GLVFF-IgG/Aβ coaggregates, which competitively inhibits amyloidosis of Aβ and the formation of toxic sAβs, and reduces the level of free preexistent sAβs in AD brain. Such NP-GLVFF-IgG/Aβ coaggregates are readily phagocytosed by entocranial microglia via recognition between IgG on the surface of coaggregates and FcRs. Cellular and animal studies indicate that the introduction of nanoscavengers significantly accelerates the clearance of sAβs through the mechanism of coaggregation induction between nanomaterials and Aβ in inflammatory conditions, thereby preventing hippocampal neuron damages in APP/PS1 mice. In view of an overwhelming majority of patients with AD displaying a proinflammatory phenotype,31,32 the nanoscavengers would provide a potential therapeutic approach. In addition, we found that the NP-GLVFF-IgG showed negligible BBB transfer after the formation of NP-GLVFF-IgG/Aβ coaggregates with larger size in vitro transwell model, which result in a reduced BBB efflux of nanoscavenger after entering the brain tissue,28,33 proposing a novel strategy for cerebral drug delivery. Figure 1 | Nanoscavengers inducing the coaggregation of sAβs and facilitating Aβ clearance in AD brain. (a) Synthesis of the nanoscavengers by a three-step process. (I) Encapsulation of SA with a cross-linked polymer shell containing GLVFF fragments synthesized by in situ polymerization of AAm, APm, Acr-GLVFF, and BIS. (II) Conjugation of IgG via thiol chemistry. (III) Reversible covalent modification with PEG-B6 via MA-amine chemistry. The PEG-B6 can detach from the nanoscavenger under acidic conditions due to the cleavage of the C–N bond. (b) Schematic diagram of the coaggregation between nanoscavengers and sAβs, and the possible mechanism of clearing Aβ by microglia. sAβs, soluble β-amyloid aggregates; Aβ, amounts of β-amyloid; AD, Alzheimer's disease; SA, serum albumin; AAm, acrylamide; APm, N-(3-Aminopropyl)-methacrylamine; Acr-GLVFF, acryloyl-Gly-Leu-Val-Phe-Phe; BIS, N,N′-methylenebisacrylamide; IgG, immunoglobulin G; MA, maleamic anhydride. Download figure Download PowerPoint Experimental Methods Preparation of nanoscavengers Synthesis of NP-GLVFF The SA was first conjugated with N-acryloxysuccinimide (NAS) to attach acryloyl groups.28 The amount of NAS [10% in dimethyl sulfoxide (DMSO), m/v] used was at a 60∶1 molar ratio (NAS to protein), and the conjugation was kept at 4 °C for 2 h. Then, the solution was dialyzed against phosphate-buffered saline (PBS) buffer to remove any unreacted NAS. The acryloylated protein concentration was tuned to 1 mg mL−1 with PBS buffer dilution. Polymerization was initiated in situ by the addition of tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) and kept at 4 °C for 2 h, using acrylamide (AAm) and Acr-GLVFF as monomers, and N,N′-methylenebisacrylamide (BIS) as cross-linker. After the polymerization, the reaction mixture was dialyzed against PBS buffer to remove unreacted monomers and byproducts. Subsequently, the solution was passed through a size-exclusion column (Sepharose 6B) to remove unreacted proteins. The molar ratio of native SA:AAm:APm:Acr-GLVFF:BIS:APS was 1∶3000∶250:75∶300∶450. The mass ratio of APS:TEMED was 1∶2. The amount of GLVFF fragments in per NP-GLVFF was confirmed via a standard curve method ( Supporting Information Figure S4). Synthesis of NP-GLVFF-IgG NP-GLVFF (1 mg, SA as the standard) was dissolved in 1 mL PBS buffer, then Mal-PEG360-NHS (30 equiv) was added. The solution was stirred at 4 °C for 2.5 h. Then, the solution was dialyzed against PBS buffer to remove any unreacted Mal-PEG360-NHS (molecular weight cut-off, MWCO: 10,000 Da). By measuring the surface amine groups on NP-GLVFF, we estimated that each NP-GLVFF contains approximately 89 (89 ± 6) amine groups. Out of the 89 amine groups, approximately eight amine groups were reacted to Mal-PEG360-NHS. Then, IgG (10 mg) was dissolved in 2 mL PBS buffer, and Traut's reagent (20 equiv) and Tris(2-carboxyethyl)phosphine (TCEP) (60 equiv) were added. The solution was stirred at room temperature for 3.5 h and dialyzed against PBS buffer. NP-GLVFF-PEG360-Mal and IgG-SH (2 equiv) were mixed in PBS buffer, and then TCEP (20 equiv) was added for 8 h. The mixture was dialyzed in PBS buffer and subjected to gel infiltration (Sepharose 6B) to obtain purified NP-GLVFF-IgG. Then, NP-GLVFF-IgG was concentrated by a Millipore ultrafiltration centrifuge tube (MWCO: 50,000 Da) and stored at −20 °C for further use. Synthesis of a nanoscavenger NP-GLVFF-IgG and Mal-PEG2000-CA (200 equiv) were mixed in sodium bicarbonate buffer (100 mM, pH 8.2), and then the solution was stirred at 4 °C overnight. Then, the solution was dialyzed and concentrated by a Millipore ultrafiltration centrifuge tube (MWCO: 100,000 Da) to remove any unreacted Mal-PEG2000-CA. Next, B6/fluorescein isothiocyanate (FITC)-B6 (100 equiv) and TCEP (200 equiv) were added at room temperature for 6 h (pH 7.4–8.0). Then, the solution was dialyzed and concentrated (MWCO: 100,000 Da) to remove unreacted B6. Binding affinity of soluble Aβ42 aggregates and NP-GLVFF-IgG Quartz crystal microbalance with dissipation monitoring (QCM-D) measurements were conducted using a Q-Sence E4 system (Q-Sence, Västra Frölunda, Sweden). The soluble Aβ42 solutions (20 μM) were obtained as previously described. The Au sensor chip was immersed in a solution of equimolar IgG, NP-GLVFF, and NP-GLVFF-IgG, which was conjugated by Traut's Reagent and reduced by TCEP overnight at room temperature. Then, the chip was rinsed with deionized water, dried with nitrogen gas, and placed into the standard flow module before measurements. Each sensor chip surface with attached nanoparticles was washed with PBS buffer for 1 h at a flow rate of 30 μL min−1 and then equilibrated at 10 μL min−1 until the baseline was stable. Then, 20 μM sAβ42 solutions in the flow buffer were injected for 30 min at 10 μL min−1 followed by continuous flow of the same buffer. All QCM experiments in this study were operated at 37 °C. sAβs phagocytosis mediated by NP-GLVFF-IgG For confocal laser scanning microscope (CLSM) observation, BV-2 cells were collected and 1 × 105 cells/well were seeded in 24-well plates overnight. The medium was replaced with fresh serum-free Dulbecco's modified Eagle's medium (DMEM). FITC-labeled sAβ42s, as markers of phagocytosis, were used in this study. The sAβ42s (20 μM) were pretreated with IgG, NP-GLVFF, and NP-GLVFF-IgG (molar ratio of Aβ42/nanoparticle ≈ 10∶1) for 30 min, and then incubated with BV-2 cells. The concentration of sAβ42s was 2.5 μM in media. After 3-h incubation, the culture medium was removed, and cells were washed with PBS buffer (×3), followed by fixing in 4% paraformaldehyde and staining with TRITC-phalloidin and 4',6-diamidino-2-phenylindole (DAPI). The lysosomes were stained with LysoTracker Red ( Supporting Information Figure S11b). Cellular phagocytosis of sAβ42s was observed with an inverted fluorescence microscope (TCS SP8, Leica, Germany). For FACS-based assays, similar procedures were performed. After 3-h incubation, BV-2 cells were washed with PBS (×3) and digested by 0.25% trypsin. Flow cytometry profiles of BV-2 cells were acquired on Guava flow cytometry. In vitro cross the BBB To construct the in vitro transwell BBB model, bEnd.3 cells were seeded on the transwells with permeable polyester membrane inserts (Corning, NY) at 1 × 105 cells/well. The medium (DMEM, 10% fetal bovine serum, FBS, 1% penicillin/streptomycin, and phenol red-free) in the upper chambers (pore size: 0.4 μm) was replaced every 2 days for 2 weeks. The cells reached confluence, and the resulting monolayer was thought to reasonably mimic BBB morphology and activity in vitro. To monitor the tightness of the monolayer, its transepithelial electrical resistance (TEER) was detected by a Millicell-ERS volt-ohmmeter (Millipore Co., Billerica, MA). A monolayer of bEnd.3 cells with ≥200 Ω·cm2 TEER was selected for further experiments. Different Cy5.5-labeled nanoparticles were introduced to the upper chambers at a final concentration of 50 μg mL−1 (SA as the standard) and incubated at 37 °C. After 6-h (or 12-h) incubation, the fluorescence levels in the bEnd.3 (insert of the transwells) layer and bottom chamber were measured. After incubation, the TEER value of each monolayer was further analyzed. As illustrated in Supporting Information Figure S12, the results showed that the resistance of bEnd.3 transwells showed negligible change, confirming the integrity of the bEnd.3 monolayer during experimentation. In vivo cross the BBB Animal experiments were carried out in accordance with the guidelines of the National Institutes of Health (Bethesda, MD), and all protocols were approved by the Committee for Animal Research at Nankai University (Tianjin, China). To validate effective penetration of phagocytosis-modulating nanoparticles to the brain, Cy5.5 was labeled in NP-GLVFF-IgG and nanoscavengers as the fluorescence probe to track the biodistribution in APP/PS1 mice. NP-GLVFF-IgG and nanoscavengers were intravenously injected via tail vein with a normalized concentration of Cy5.5 to 6.5-month-old APP/PS1 mice. The brain and major organs were harvested for ex vivo imaging, and ROI fluorescence intensity (FI) of the Cy5.5 signal was measured by an IVIS Imaging System (Caliper Life Sciences, Waltham, MA) 6-h postinjection. Treatment schedule APP/PS1 mice and wild-type (WT) mice were maintained for about 7.5–8 months. To confirm the inflammation burdens in the AD brain, APP/PS1 mice and WT mice were randomly grouped for western blotting at the 28th week after birth before treatment (three mice per group). At the 28th week, 24 mice were randomly divided into four groups (six mice per group) and intravenously injected with PBS (APP/PS1), NP-GLVFF-IgG, NP-GLVFF-B6, and Nanoscavengers (150 µL, 1 mg mL−1, SA as the standard), respectively, every other day until the 32nd week after birth. The therapeautic effects of the mice (six mice per group) were evaluated by the Morris water maze (MWM) test and sacrificed for immunofluorescence staining, WB, and H&E staining. Results and Discussion Nanoscavenger synthesis was achieved via a three-step process (Figure 1a). Aiming at a high specific surface area allowing Aβ binding to the surface of NP-GLVFF-IgG, a small-sized serum albumin (SA) was employed as the structural foundation for nanoscavenger preparation. First, NP-GLVFF was prepared by encapsulating an albumin molecule with a thin layer of cross-linked polymer shell containing GLVFF fragments via an in situ polymerization method ( I). After the polymerization, NP-GLVFF was conjugated with IgG via thiol chemistry ( II) to yield NP-GLVFF-IgG. Successful integration of GLVFF was confirmed by an UV–vis spectrophotometer method (Figure 2b and Supporting Information Figure S4). Compared with albumin NP without GLVFF (denoted as NP), NP-GLVFF exhibited a higher absorption at 250–280 nm, which was attributed to the UV absorption of phenylalanine residues (Phe, F) of GLVFF. Further studies on NP-GLVFF-IgG were achieved by comparing the morphology changes before and after IgG conjugation using dynamic light scattering (DLS) and transmission electron microscopy (TEM). DLS results indicate increased particle size from 16 ± 3 nm of NP-GLVFF to 34 ± 5 nm of NP-GLVFF-IgG ( Supporting Information Figure S6a), which was then confirmed with TEM observations (Figure 2a). Considering the relatively large hydrodynamic size of IgG, the significantly increased particle size indicated successful conjugation of IgG. To further confirm successful covalent conjugation, NP-GLVFF and IgG were prelabeled with rhodamine B isothiocyanate (NP-GLVFF-RhB) and fluorescein isothiocyanate (IgG-FITC) prior to the conjugation, respectively. Figure 2c presents fluorescence images of NP-GLVFF-IgG, showing the colocalization of NP-GLVFF-RhB (red) and IgG-FITC (green). Förster resonance energy transfer (FRET) analysis showed effective energy transfer in NP-GLVFF-IgG, whereas negligible energy transfer was observed when IgG-FITC and NP-GLVFF-RhB were mixed directly, indicating the successful covalent conjugation of NP-GLVFF and IgG (Figure 2d).34,35 To further confirm the formation of the linkage between NP-GLVFF and IgG (prelabelled with FITC), an assay based on agarose gel electrophoresis was performed. As shown in Supporting Information Figure S6c, a significant increase in molecular weight was observed when modifying IgG onto NP-GLVFF, suggesting linkage formation. Quantitative analysis suggested that 18 ± 2.5 GLVFF fragments and 1.3 ± 0.2 IgG molecules were conjugated per NP-GLVFF-IgG. Finally, the nanoscavenger was prepared by surface modifying NP-GLVFF-IgG with MA-PEG-B6 via maleamic anhydride (MA)-amine chemistry between monosubstituted MA and amines ( III). First, long-term stability analysis of the nanoscavenger was studied by DLS analysis. According to the results, no significant changes in size distribution were observed in PBS or in the presence of serum ( Supporting Information Figure S6d). To recover the capability of nanoscavengers to facilitate the clearance of Aβ, the conjugated PEG-B6 was designed to detach from nanoscavengers after transport across the BBB. To demonstrate, assays based on agarose gel electrophoresis were performed. Briefly, the B6 peptide was labeled with FITC before conjugating to NP-GLVFF-IgG. After conjugation, nanoscavengers were incubated in acidic buffers (pH 5.5) to the endosomal of cerebral during the transcytosis across BBB. Compared with pH the nanoscavenger into the acidic environment all of the MA-amine after 8 h, leading to the of the PEG-B6 shell (Figure of PEG-B6 from nanoscavengers was further confirmed using a As shown in Figure the energy transfer was significantly reduced in pH after incubation, indicating successful between PEG-B6 and NP-GLVFF-IgG. Figure 2 | Nanoscavenger and coaggregation with (a) TEM images of 50 (b) UV–vis of NP-GLVFF and NP without GLVFF images of NP-GLVFF-IgG 10 of a mixture of NP-GLVFF and IgG before and after (red) the IgG and NP-GLVFF were prelabeled with FITC and respectively. were with at gel electrophoresis results of nanoscavengers in The PEG-B6 was prelabeled with analysis of nanoscavengers in pH after PEG-B6 and NP-GLVFF-IgG were prelabeled with FITC and respectively. The were with at of Aβ (20 μM) incubated with IgG, NP-GLVFF and NP-GLVFF-IgG at 37 °C in The molar ratio of was assays showing the formation of soluble Aβ when Aβ with IgG, NP-GLVFF, and NP-GLVFF-IgG after 24 h. Aβ incubated in PBS was employed as the of soluble Aβ in the presence of NP-GLVFF-IgG. was with The concentration of Aβ was 10 The molar ratio of was the binding affinities of sAβs to IgG, NP-GLVFF, and NP-GLVFF-IgG at 37 °C. the binding affinities of NP-GLVFF-IgG to SA, and sAβs at 37 °C. Schematic of the of free and sAβs to the Aβ-binding of NP-GLVFF-IgG. assays showing the binding affinities between sAβs and IgG, NP-GLVFF, and NP-GLVFF-IgG The molar ratio of was images of the mixture of NP-GLVFF-IgG and sAβs after 6-h NP-GLVFF-IgG and sAβs were prelabeled with and 30 TEM images of NP-GLVFF-IgG/Aβ coaggregates. 50 are as ± from experiments sAβs, soluble β-amyloid aggregates; crystal microbalance with dissipation transmission electron Förster resonance energy phosphate-buffered IgG, immunoglobulin G; analysis of Download figure Download PowerPoint that neurotoxic sAβs, as are major of the inflammatory synaptic and neuronal Nanoscavengers were designed to with Aβ, thereby inhibiting amyloidosis and the formation of sAβs the To this we first employed a fluorescence assay to the amyloidosis of Aβ in the presence of NP-GLVFF-IgG of Figure a of Aβ Aβ (20 μM) was incubated at 37 increased and reached a after h, indicating Aβ results were observed from the Aβ incubated with IgG In of and were observed when Aβ with NP-GLVFF and NP-GLVFF-IgG, respectively, indicating significant of Aβ Then, assay using Aβ was employed to the formation of soluble Aβ during this process. As with Aβ significantly levels of Aβ were observed when Aβ with NP-GLVFF and NP-GLVFF-IgG (Figure Finally, the of the at 24 h after was This was achieved by the with cells for 24 h and the using a As shown in Figure Aβ exhibited neuron toxicity In the NP-GLVFF and NP-GLVFF-IgG cells showed higher confirming the capability of NP-GLVFF-IgG in inhibiting the formation of neurotoxic soluble large amounts of neurotoxic sAβs are in the brain of AD patients prior to the For effective AD it is crucial to or the preexistent To this we first the of nanoscavengers on collecting preexistent sAβs, the was previously described. The affinities between the NP-GLVFF-IgG and sAβs were first evaluated via As shown in Figure significant were observed when the sAβs to NP-GLVFF-IgG and NP-GLVFF and results that the NP-GLVFF-IgG was of binding to sAβs with high due to the multivalent interactions between sAβs and GLVFF fragments on Further measurements via assay confirmed this Briefly, sAβs were incubated with IgG, NP-GLVFF, and NP-GLVFF-IgG at 37 °C for 6 h was respectively. Then, the free sAβs in solutions were using a specific As shown in and high levels of free sAβs were detected from and groups, indicating interactions between sAβs and IgG. In significantly levels of free sAβs were detected when sAβs with NP-GLVFF-IgG, suggesting strong the coaggregation of NP-GLVFF-IgG and sAβs was evaluated by monitoring the increased scattering light using DLS As shown in Supporting Information Figure a increase in scattering light intensity was observed when sAβs with NP-GLVFF-IgG for 6-h incubation, indicating the formation of large due to the coaggregation of NP-GLVFF-IgG and A similar increase was also observed sAβs with ( Supporting Information Figure In negligible were observed when sAβs NP-GLVFF-IgG or the mixture of sAβs and IgG ( Supporting Information Figure Figure presents the fluorescence images of NP-GLVFF-IgG after 6-h with fluorescein sAβs