Steric Hindrance-Mediated Enzymatic Reaction Enable Homogeneous Dual Fluorescence Indicators Aptasensing of Hepatocellular Carcinoma CTCs.

Circulating tumor cells (CTCs) serve as important biomarkers in the liquid biopsy of hepatocellular carcinoma (HCC). Herein, a homogeneous dual fluorescence indicators aptasensing strategy is described for CTCs in HCC, with the core assistance of a steric hindrance-mediated enzymatic reaction. CTCs in the sample could specifically bind to a 5'-biotin-modified glypican-3 (GPC3) aptamer and remove the steric hindrance formed by the biotin-streptavidin system. This influences the efficiency of the terminal deoxynucleotidyl transferase enzymatic reaction. Then, methylene blue (MB) was introduced to react with the main product poly cytosine (polyC) chain, and trivalent cerium ion (Ce3+) was added to react with the byproduct pyrophosphate to form fluorescent pyrophosphate cerium coordination polymeric nanoparticles. Finally, the CTCs were quantified by dual fluorescence indicators analysis. Under optimized conditions, the linear range was 5 to 104 cells/mL, and the limits of detection reached 2 cells/mL. Then, 40 clinical samples (15 healthy and 25 HCC patients) were analyzed. The receiver operating characteristic curve analysis revealed an area under the curve of 0.96, a sensitivity of 92%, and a specificity of 100%. Therefore, this study established a sensitive and accurate CTCs sensing system for clinical HCC patients, promoting early tumor diagnosis.

Nucleic Acid and Nanomaterial Synergistic Amplification Enables Dual Targets of Ultrasensitive Fluorescence Quantification to Improve the Efficacy of Clinical Tuberculosis Diagnosis.

Interferon-γ (IFN-γ) release assays (IGRAs) are constrained by the limited diagnostic performance of a single indicator and the excessive Mycobacterium tuberculosis (Mtb) antigen stimulation time. This study presents a simultaneous, homogeneous, rapid, and ultrasensitive fluorescence quantification strategy for IFN-γ and IFN-γ-induced protein 10 (IP-10). This method relies on the high-affinity binding of aptamers to IFN-γ and IP-10, the enzyme-free catalytic hairpin assembly reaction, and the heightened sensitivity of CdTe quantum dots to Ag+ and hairpin structure C-Ag+-C and carbon dots to Hg2+ and hairpin structure T-Hg2+-T. Under optimized conditions, the selectivity of IFN-γ and IP-10 was excellent, with a linear range spanning from 1 to 100 ag/mL and low limits of detection of 0.3 and 0.5 ag/mL, respectively. Clinical practicality was confirmed through testing of 57 clinical samples. The dual-indicator combination detection showed 92.8% specificity and 93.1% sensitivity, with an area under the curve of 0.899, representing an improvement over the single-indicator approach. The Mtb antigen stimulation time was reduced to 8 h for 6/7 clinical samples. These findings underscore the potential of our approach to enhance the efficiency and performance of a tuberculosis (TB) clinical diagnosis.

DNAzyme and controllable cholesterol stacking DNA machine integrates dual-target recognition CTCs enable homogeneous liquid biopsy of breast cancer.

Although circulating tumor cells (CTCs) have demonstrated considerable importance in liquid biopsy, their detection is limited by low concentrations and complex sample components. Herein, we developed a homogeneous, simple, and high-sensitivity strategy targeting breast cancer cells. This method was based on a non-immunological stepwise centrifugation preprocessing approach to isolate CTCs from whole blood. Precise quantification is achieved through the specific binding of aptamers to the overexpressed mucin 1 (MUC1) and human epidermal growth factor receptor 2 (HER2) proteins of breast cancer cells. Subsequently, DNAzyme cleavage and parallel catalytic hairpin assembly (CHA) reactions on the cholesterol-stacking DNA machine were initiated, which opened the hairpin structures T-Hg2+-T and C-Ag+-C, enabling multiple amplifications. This leads to the fluorescence signal reduction from Hg2+-specific carbon dots (CDs) and CdTe quantum dots (QDs) by released ions. This strategy demonstrated a detection performance with a limit of detection (LOD) of 3 cells/mL and a linear range of 5-100 cells/mL. 42 clinical samples have been validated, confirming their consistency with clinical imaging, pathology findings and the folate receptor (FR)-PCR kit results, exhibiting desirable specificity of 100% and sensitivity of 80.6%. These results highlight the promising applicability of our method for diagnosing and monitoring breast cancer.

Biomolecule-regulation of fluorescent probe signaling: Homogeneous rapid portable protease sensing in serum.

BACKGROUND: As is well documented, prostate cancer (PCa) being the second most prevalent cancer in men worldwide, emphasizing the importance of early diagnosis for prognosis. However, conventional prostate-specific antigen (PSA) testing lacks sufficient diagnostic efficiency due to its relatively low sensitivity and limited detection range. Mounting evidence suggests that matrix metalloproteinase 9 (MMP-9) expression increases with the aggressive behavior of PCa, highlighting the significance of detecting the serum level of MMP-9 in patients. Developing a non-immune rapid, portable MMP-9 detection strategy and investigating its representativeness of PCa serum markers hold considerable implications. RESULTS: Herein, our study developed a simple, homogeneous dual fluorescence and smartphone-assisted red-green-blue (RGB) visualization peptide sensor of MMP-9, utilizing cadmium telluride quantum dots (CdTe QDs) and calcein as signal reporters. The essence of our approach revolves around the proteolytic ability of MMP-9, exploiting the selective recognition of molecule-Cu2+ complexes with different molecular weights by CdTe QDs and calcein. Under optimized conditions, the limits of detection (LODs) for MMP-9 were 0.5 pg/mL and 6 pg/mL using fluorescence and RGB values readouts, respectively. Indeed, this strategy exhibited robust specificity and anti-interference ability. MMP-9 was quantified in 42 clinical serum samples via dual-fluorescence analysis, with 12 samples being visually identified with a smartphone. According to receiver operating characteristic curve (ROC) analysis, its sensitivity and specificity were 90 % and 100 %, respectively, with an area under curve (AUC) value of 0.903. SIGNIFICANCE AND NOVELTY: Of note, the results of the aforementioned analysis were highly consistent with the serum level of PSA, clinical color Doppler flow imaging (CDFI), and histopathological results. Therefore, this simple, rapid, homogeneous fluorescence and visualization strategy can reliably measure MMP-9 levels and exhibit promising potential in point-of-care testing (POCT) applications for PCa patients.