Poly(amino acid) Multilayers Modified Dendritic Mesoporous Silica Nanoparticles Achieve Effective Enzyme Stability for Ultrasensitive Immunoassay

Abstract

Enzyme-linked immunosorbent assay (ELISA) is one of the most common techniques in biomedical detection; however, the poor sensitivity in early diagnosis for some diseases seriously limits its application. In this work, we developed an ultrasensitive ELISA system that is based on horseradish peroxidase (HRP)-loaded dendritic mesoporous silica nanoparticles (DMSN) modified with poly­(amino acid) multilayers (defined as DSHP). A large amount of HRP adsorption was achieved in center-radial mesoporous channels of DMSN because of the high specific surface area and large pore size, leading to significant signal amplification. Additionally, DSHP could not only effectively maintain HRP activity for at least 10 days but also provide preferable protection for HRP activity even at high temperatures or a wide pH range. Moreover, the DSHP system exhibited admirable signal amplification performance with a limit of detection of 0.667 fM and a wide detectable range from 6.67 × 10–4 to 6.67 × 105 pM, whose sensitivity was 104 times higher than that of the conventional ELISA. We believe that the DSHP will offer a new strategy for signal amplification of the ELISA system in clinical diagnosis.

Modified ELISA for Ultrasensitive Diagnosis

“…This assay used an optofluidic chip technique integrated with directly printed, high-quality-factor polymer microlaser sensors and optical whispering-gallery-mode microcavities for an ultrasensitive ELISA. Another ultrasensitive ELISA was developed using horseradish peroxidase-loaded dendritic mesoporous silica nanoparticles modified with poly(amino acid) multilayers [ 28 ]. The LOD of this assay was 10 4 times lower than that of a conventional ELISA.…”

“…The strongest requirement for conventional ELISA is the ability for ultrasensitive detection [ 26 , 27 , 28 ]. The term ‘ultrasensitive’, however, is often misinterpreted.…”

Double-Enzyme Active Vanadium Nanospheres-Mediated Ratiometric Multicolor Immunosensors for Sensitive Detection of the T-2 Toxin

“…The difficult storage conditions, high cost, and ease of inactivation of natural enzymes, however, make them particularly inhospitable to remote and economically underdeveloped areas. Additionally, the low loading capacity of natural enzymes, which typically leads to low sensitivity, renders this approach unsuitable for the micro-detection of toxins …”

“…Additionally, the low loading capacity of natural enzymes, which typically leads to low sensitivity, renders this approach unsuitable for the micro-detection of toxins. 5 Nanomaterials with enzyme-like activity (nanozymes), 6 when compared to natural enzymes, have gradually become a research hotspot in the fields of environmental protection, 7 tumor treatment, 8 and analytical sensing 9 due to advantages such as low cost, simple synthesis, remarkable catalytic performance, and low environmental impact. 10 In the field of analytical sensing, a large number of artificial nanozymes, especially metal-based enzyme-like catalysts, have been successfully developed to replace natural enzymes, such as the Ni-nanoparticle/polypyrrole composite, 11 the bismuth oxide ferrite nanoparticle, 12 platinum single-atom nanozymes, 13 etc., which have been successfully used in biosensing.…”

Dual-Mode Immunosensor for Electrochemiluminescence Resonance Energy Transfer and Electrochemical Detection of Rabies Virus Glycoprotein Based on Ru(bpy)32+-Loaded Dendritic Mesoporous Silica Nanoparticles

“…Compared to conventional mesoporous silica, the dendritic mesoporous silica nanoparticles (DMSNs) have received considerable attention due to their extrusive physical properties, including the center-radial oriented open and large mesopores, the open three-dimensional dendritic structure, and the high specific surface area . DMSNs represent a novel class of nanocarriers for loading signal-generating materials such as quantum dots, nano-gold, horseradish peroxidase, and AuAg nanoclusters . Additionally, DMSNs with a larger dendritic mesoporous structure expose more active sites, allowing other substances to access and participate in the reaction better.…”