Ultrasensitive Sensor Using Quantum Dots-Doped Polystyrene Nanospheres for Clinical Diagnostics of Low-Volume Serum Samples

Abstract

Development of sensitive homogeneous assays is a high-priority research target for clinical diagnostics. Quantum dots (QDs) present favorable photophysical properties, which implies their potential as an exceptional dye in fluorescence detection. QDs-based biosensors have been described in the literature; however, few of them have truly progressed to widespread clinical usage. In this work, a chemiluminescent homogeneous detecting biosensor is fabricated using QDs-doped polystyrene nanospheres to sensitively detect biomarkers in low-volume serum samples. Phthalocyanine-dyed and QDs-encapsulated carboxylate-functionalized polystyrene nanospheres with surface carboxyl groups (PPs and QPs, respectively) were fabricated and served as triggers and fluorescent probes, respectively, in this biosensing system. In this sandwich-format immunoassay, the PPs produced singlet oxygen once sensitized by 680 nm diode lasers, and the QPs, conjugated with antibodies, and then reacted with the singlet oxygen in the presence of specific antigens and emitted anti-Stokes fluorescence with wavelengths around 605 nm, as a result of fluorescence resonance energy transfer (FRET) within the QPs. We demonstrated the determination of carcinoembryonic antigen as a model protein target in 25 μL of serum samples with an unprecedented detection limit of 2.56 × 10–13 M (46 pg/mL) using this biosensor. Furthermore, excellent correlations (R 2 = 0.99718, n = 107) were obtained between utilizing this biosensor and commercialized chemiluminescence immunoassay kits in clinical serum detection. These results demonstrate that our flexible and reliable biosensor is suitable for direct integration into clinical diagnostics, and it is expected to be a promising diagnostic tool for early detection and screening tests as well as prognosis evaluation for patients.

Progress and challenges in functional nanomaterial‐based suspension array technology for multiplexed biodetection

“…[ 12 ] During the past 20 years, considerable progress has been made with respect to QDs, while issues of hydrophobicity, surface modification, and poor photostability in water have hampered their practical applications to in vitro labeling in diagnostic fields. [ 44,45 ] Although UCNPs provide low background interference, they have not yet been used as labels in SAT platforms because of their multicolor emission properties and relatively low QY. In particular, AIEgens possess many excellent optical properties and have great potential as labels.…”

A Photosensitized Singlet Oxygen (1O2) Toolbox for Bio-Organic Applications: Tailoring 1O2 Generation for DNA and Protein Labelling, Targeting and Biosensing

“…For the detection of carcinoembryonic antigen (CEA), a sandwich ELISA-like assay was developed, exploiting the FRET emission of PS-containing polystyrene nanoparticles (functionalized with streptavidin), and quantum dot-doped nanoparticles (decorated with an anti-CEA monoclonal antibody). In the presence of the analyte, the FRET emission allowed the light-induced 1 O 2 production, which triggers chemiluminescent emission from the quantum dots [ 217 ]. Other very recent applications in this context were developed by the Zhang group, who realized ECL-based biosensors for the detection of polynucleotide kinase (PNK), an enzyme implicated in the oligonucleotide metabolism [ 218 ].…”

Fluorescence resonance energy transfer-based drug delivery systems for enhanced photodynamic therapy

“…[90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105] Autofluorescence excited FRET mechanism Advantages: high 1 O 2 production and deep tissue penetration. [107][108][109][110][111][112][113][114]115 Shortages: autofluorescence is highly dependent on the catalytic reaction. 107,115 Please do not adjust margins Please do not adjust margins…”

“…107 Inspired by the light-generating reactions used by fireflies and jellyfish, many auto-fluorescent, FRET-based nanomaterials have been constructed for various bioapplications, including immunoassay analysis, 108 inflammation detection, 109,110 drug delivery, 111 tumor imaging, 112 DNA detection, 113 and clinical disease diagnostics. 114 Bioluminescence is an important auto-fluorescence generated from a chromophore substrate catalysed by an enzyme. 115 This bioluminescence can be used to excite PSs to efficiently produce ROS via a bioluminescence resonance energy transfer (BRET) approach.…”