Nanoscale Technologies in Highly Sensitive Diagnosis of Cardiovascular Diseases

Abstract

Cardiovascular diseases (CVD) are the leading cause of death and morbidity in the world and are a major contributor to healthcare costs. Although enormous progress has been made in diagnosing CVD, there is an urgent need for more efficient early detection and the development of novel diagnostic tools. Currently, CVD diagnosis relies primarily on clinical symptoms based on molecular imaging (MOI) or biomarkers associated with CVDs. However, sensitivity, specificity, and accuracy of the assay are still challenging for early-stage CVDs. Nanomaterial platform has been identified as a promising candidate for improving the practical usage of diagnostic tools because of their unique physicochemical properties. In this review article, we introduced cardiac biomarkers and imaging techniques that are currently used for CVD diagnosis. We presented the applications of various nanotechnologies on diagnosis within cardiac immunoassays (CIAs) and molecular imaging. We also summarized and compared different cardiac immunoassays based on their sensitivities and working ranges of biomarkers.

Keywords: biomarker; cardiovascular disease (CVD); diagnostic; molecular imaging; nanotechnology.

FIGURE 1

Cardiovascular diseases (CVDs), their risk factors, and their diagnosis settings include molecular imaging and cardiac immunoassay within the nanotechnology platform. Ab₁, capture antibodies that immobilize the targets. Ab₂, detection or secondary antibodies that detect and quantify the targets.

FIGURE 2

(A) (a) The schematic of fabricating ECL immunoassay and its possible self-enhanced luminescence mechanism. A sandwich detection format was utilized to detect NT-proBNP. Ab₁ was immobilized via Au-NH₂ bond and dried on AgNC-sem@AuNP modified GCE surface, once the NT-proBNP was captured, the MIL-125 labeled Ab₂ was added to quench the ECL luminophore. The resonance energy transfer was due to the partial overlap between the ECL emission of the AgNC-sem@AuNPs (wavelength 470–900 nm) and the visible adsorption spectrum of MIL-135 (wavelength 406–900 nm). (b) The preparation of self-enhanced luminophore AgNC-Sem@AuNPs. AuNPs combined with Sem-AgNCs with Au-NH₂ bond. (Dong et al., 2019) Copyright 2020 Springer Nature Switzerland AG. (B) Schematic Illustration of ECL-HCR Immunosensor. AuNPs modified GCE immobilized Ab₁ via Au-N and Au-S bonds, and then AuNPs/GCE was prepared by electrodepositing in HAuCl₄ solution. The Ab₂-AuNP-T₁ opened hairpin DNA structures (H1 and H2 after cTnI was caught), which triggered hybridization that modified Au NCs on the electrode. Au NCs reacted with K₂S₂O₂ thus emitted the ECL signal (Zhu et al., 2019). Copyright 2020 American Chemical Society. (C). The mechanism of nanozyme-linked immunosorbent assay for dual colorimetric and ratiometric fluorescent detection. OPD was oxidized and converted into oxOPD by the robust nanozyme of nanoceria with peroxidase-like properties, resulting an emission maximum of oxOPD at 578 nm. OxOPD was immobilized on the surface of g-C₃N₄ QDs, which led to a ratiometric fluorescence response as a result of photoinduced electron transfer (PET). The combination of ratiometric fluorescent assay with colorimetric assay could quantify cTnI (Miao et al., 2019). Copyright 2020 from Elsevier B.V. (D) Schematic of UCNPs based immunoassay and the synthesis, surface modification of core-shell UCNPs. UCNPs-Ab₁ and UCNPs-rabbit IgG were added on the conjugate pad, the second anti-(MB Ab₁) and anti- (rabbit IgG) antibodies were separately stripped onto the NC membrane. Samples will be captured on the sample pad. UCNPs on the test and control line was excited by a continuous wave laser diode at 908 nm for reading. The Poly (acrylic acid) PAA was added to the core-shell NaYF_4: Yb, Er@NaLuF₄ nanoparticles, and yield UCNPs@PAA particles. Then UCNPs@PAA were conjugated with Ab₁ using 1-Ethyl-3-(3-dimethyllaminopropyl) carbodiimide hydrochloride (EDC-HCl) and N-Hydroxysulfosuccinimide sodium salt (Sulfo-NHS) as cross-linking agents (Ji et al., 2019). Copyright 2020 from Elsevier B.V.

FIGURE 3

(A) Scheme of the proposed liposomal PEC Immunoassay. Ab₁ were first loaded into 96-well plates, and then samples were incubated with Ab₁ for 1 h. The QDLL-Ab₂ was introduced after the immunorecognition of cTnI. Triton X-100 (10%) was introduced to release the QDs that were later captured by TiO₂-NTs electrode. The photocurrents were generated due to the sensitization effect (Xue et al., 2019). Copyright 2020 American Chemical Society. (B) Schematic principle of cTnI detection using PMSN/Cu2+/ssDNAs. Positive-charged PMSNs were added into Cu²⁺ solutions. Cu²⁺ entered the pores of PMSNs via diffusion. Later, ssDNAs bound cTnI specifically was added and attached on the surface of PMSNs. Once the cTnI was recognized by ssDNAs, the complexes reacted with CdS that was functionalized onto the PSATs, to form Cu_xS and diseased the photocurrent signal. The changes of photocurrent were correlated to the concentration of cTnI (Gao et al., 2019). Copyright 2020 from Elsevier B.V.

FIGURE 4

(A) Schematic illustration for aptasensor fabrication and MB detection process. BNNSs were obtained from filtered BN powder dissolved solution via hydrothermal method. BNNSs were spinning deposited onto FTO electrode. AuNPs were then functionalized onto BNNS/FTO electrode to form AuNPs/BNNSs/FTO electrode acted a transducer to fix a thiol-functionalized DNA aptamer (Apt) via the Au-S covalent interaction. The [Fe(CN)6]3-/4- was used as a redox probe to monitor the oxidation current variation after MB binding to the Apt (Adeel et al., 2019). Copyright (© 2020 from Elsevier B.V. (B). The illustration of electrochemical immunosensor. DIL was noncovalently non-covalently bonded with HCNTs to form the DIL-HCNTs composite, which provided sufficient binding sites for Ab1. After antigen was capture by Ab1, the sandwich immunocomplexes formed on the electrode hindered electron transfer thus decreased the peak current of DPV. The signals were corresponded to concentrations of cTnI (Shen et al., 2019). Copyright 2020 American Chemical Society. (C) The preparation procedure of the sandwich-type electrochemical immunosensor. Dispersed Fe₃O₄-NH₂ and glutaraldehyde was stirred to form Fe₃O₄-Ab₁, BSA was added to block remaining active sites on the surface of Fe₃O₄. CoPc NPs were first dispersed in the mesoporous of Fe₃O₄-Ab₁, then APSM was used to cap on the mesoporous of Fe₃O₄-Ab₁ by electrostatic interaction and formed APSM-capped CoPc NPs- Fe₃O₄-Ab₁. Once the target cTnI was captured, CoPC NPs were released after APSM was separated. The CoPC NPs oxidized the cobalt element from Co (I) to Co (II) with H₂O₂. The reduction current was corresponded to concentrations of cTnI (Ma et al., 2019). Copyright 2020 from Elsevier B.V. (D) The schematic diagrams of preparing Au@AgNC/N, S-rGO-Ab₂. Au solation was mixed with AA and AgNO3 in turn, then the Au@AgNC were collected using centrifugation. Later, Au@AgNC and S-rGO were reacted for 8 h for Au@AgNC and S-rGO composite. Ab₂ solution was added into Au@AgNC/N and S-rGO, and oscillated to form Au@AgNC/N, S-rGO-Ab₂. AuNC/GO immobilized Ab₁ via amino-Au affinity. Once cTnI was captured, the catalyzed-oxidation of o-phenylenediamine (o-PD) with H₂O₂ was accelerated. The oxidation generated 2,3-diaminophenazine that gained in electrons and hydrogen and generated a larger current signal of DPV at 0.34 V (Lv et al., 2019). Copyright 2020 Springer Nature Switzerland AG.

FIGURE 5

(A) The schematic diagram of experimental procedure. A bare Au film with soaked into DA solution in Tris-buffer to form PDA-Au film. Afterward, AuNPs were deposited onto PDA-Au film with the help of HAuCl₄ to improve the sensitivity. After 30 min, Ab₁ was immobilized on the PDA-Au for further cTnI capture. As for detection probe, Fe₃O₄@PDA-detection antibody immune probe was collected with external magnet after Fe₃O₄@PDA and detection antibody were mixed and shake for 24 h. Then samples with different concentrations of cTnI were incubated with Fe₃O₄@PDA-detection antibody, and the nanoconjugates were collected by a magnet. Once the resonant wavelength of probes was stable, MWCNTS-PDA-AgNPs/secondary antibody was added to enhance SPR response signals (Chen et al., 2019). Copyright 2020 from Elsevier B.V. (B) Schematic of In₂O₃ nanoribbon biosensor and electronic ELISA for cardiac biomarker detection. The first shadow mask was attached onto the SiO2/Si wafer, and then In₂O₃ ribbons were deposited using radio frequency (RF). Nanoribbons were obtained after removing first-layer shadow mask. A second shadow mask was attached to define the Ti/Au disposition, which used e-beam evaporation. Finally, a FET-based sensor was completed after removing shadow mask. Captured antibodies were fixed on the In₂O₃ surface and captured the biomarkers. Biomarkers were fixed between the capture antibody and a biotinylated secondary antibody that is specific to biomarkers. The biotin tales of the secondary antibody was to capture streptavidin, which bound to a biotinylated urease that led to deprotonation the hydroxyl groups on the nanoribbon and increased the negative surface charges. The change of surface charge was detected by FET sensor because negative charges decreased the conduction of nanoribbons (Liu Q. et al., 2016). Copyright 2020 American Chemical Society. (C) Schematic representation of the preparation of antibody-modified nanoprobes involved in the lateral flow immunoassay. Carboxylated Nanospheres (CNs) were incubated with N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride crystalline (EDC) and N-hydroxysulfosuccinimide sodium salt (sulfo-NHS), the mixtures were collected centrifugation. TP110 (detection antibody) was incubated with CNs at 5.8, 6.8, or 7.8 pH. Florescent molecules were conjugated with CNs-TP110 for later detection on LFA. Briefly, sample flowed through sample pad, and conjugated with fluorescent labeled CNs-TP110 on the conjugate pad. The complexes went through NC membrane that immobilized Ab1 (3H9) on the test line and Goat anti-mouse on the control line for further antigen capture. The strip was read by a fluorescent analyzer after 15 min (Lou et al., 2019b). Copyright 2020 American Chemical Society. (D) Scheme of fabrication of the microfluidic paper-based device (μPAD) for multiplex detection of cardiac markers. Capture antibodies were immobilized onto NC membrane at three positions (G for GPBB, M for CK-MB, and T for troponin T). Serum sample was added at central sample zone. After antibody-antigen capture, AuNPs conjugated anti-cTnT (red), silver-nanoparticles (AgNPs) conjugated anti-GPBB (yellow) and Gold urchin nanoparticles conjugated anti-CKMB (purple) were added for color detection (Lim et al., 2019). Copyright 2020 from Elsevier B.V.