An electrochemical biosensor to assay Trop-2 of breast cancer cells fabricated by methylene blue-assisted assembly of DNA nanoparticles

Chitosan Nanoparticles Encapsulate Antimicrobial Peptides for the Prevention and Control of Citrus reticulata Huanglongbing and Their Distribution in Plants

Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CLas), is a serious bacterial disease affecting citrus. This study found that the expression of long stable antimicrobial peptide (LSAMP) increases with citrus immune genes CsPR1, CsPR2, and CsNPR1, indicating a link to citrus immunity. Additionally, cut antimicrobial peptide (CAMP) functions similarly to stable antimicrobial peptide (SAMP) in inhibiting CLas proliferation and boosting immunity in periwinkle (Catharanthus roseus). Chitosan nanoparticles (CS-NPs) were synthesized to encapsulate CAMP (CAMP-NPs) and SAMP (SAMP-NPs), which improved their stability and bioavailability. Both CAMP-NPs and SAMP-NPs outperformed their unencapsulated forms in inhibiting CLas proliferation and enhancing immunity in HLB-infected periwinkle and citrus; they also enhance citrus photosynthesis. Confocal microscopy revealed that CS-NPs mainly localized in the leaf apoplast but also penetrated chloroplasts. This study offers a novel biological control strategy for HLB and provides a practical framework for utilizing CS-NPs loaded with antimicrobial peptides (AMPs) for plant disease resistance.

Combining Contrast-Enhanced Ultrasound with Methylene Blue for Detection of Sentinel Lymph Nodes in Early Breast Cancer

Aims/Background Sentinel lymph nodes (SLNs) are an important prognostic factor for breast cancer patients, but traditional axillary lymph node dissection methods have many complications, while sentinel lymph node biopsy has been developed as a better method. This study aimed to evaluate the efficiency of combining contrast-enhanced ultrasound (CEUS) with methylene blue for identifying SLNs in early-stage breast cancer patients. Methods This retrospective study included clinical data from 163 female patients with lymph node-negative and T1-2 early breast cancer admitted to China-Japan Friendship Hospital between August 2022 and November 2023. All patients received a periareolar injection of SonoVue followed by ultrasonography to identify SLNs. The methylene blue was used to detect SLNs during the surgery, and the patients underwent sentinel lymph node biopsy. We compared the methylene blue method with combined CEUS and methylene blue to identify the number of SLNs per patient. Furthermore, these two methods were compared to determine the number of SLNs and the number of SLNs positive in 34 SLNs positive patients. Results This study included 163 patients with tumor (T)1-2 node (N)0-3 metastasis (M)0. The identification rate of SLNs was 100% for CEUS. We detected 376 SLNs using a combined CEUS and methylene blue method, with a median of 2 (1, 5). Furthermore, methylene blue identified 627 SLNs, with a median of 3 (1, 12). However, CEUS detected a significantly lower number of SLNs than those identified by methylene blue (p < 0.001). Additionally, metastasis frequency was substantially higher for the combined CEUS and methylene blue method (66.3%, 53/80) compared to methylene blue approach alone (39.5%, 58/147) (p < 0.001). Conclusion Combining CEUS with methylene blue is expected to improve the accuracy of axillary staging in breast cancer patients while reducing surgical trauma and postoperative complications.

Electrochemical biosensors for early detection of breast cancer

Breast cancer continues to be a significant contributor to global cancer deaths, particularly among women. This highlights the critical role of early detection and treatment in boosting survival rates. While conventional diagnostic methods like mammograms, biopsies, ultrasounds, and MRIs are valuable tools, limitations exist in terms of cost, invasiveness, and the requirement for specialized equipment and trained personnel. Recent shifts towards biosensor technologies offer a promising alternative for monitoring biological processes and providing accurate health diagnostics in a cost-effective, non-invasive manner. These biosensors are particularly advantageous for early detection of primary tumors, metastases, and recurrent diseases, contributing to more effective breast cancer management. The integration of biosensor technology into medical devices has led to the development of low-cost, adaptable, and efficient diagnostic tools. In this framework, electrochemical screening platforms have garnered significant attention due to their selectivity, affordability, and ease of result interpretation. The current review discusses various breast cancer biomarkers and the potential of electrochemical biosensors to revolutionize early cancer detection, making provision for new diagnostic platforms and personalized healthcare solutions.

Sequentially Activated-Dumbbell DNA Nanodevices for Accurate Detection of Uracil-DNA Glycosylase via PER-Based Orthogonal Signal Outputs

Accurate and reliable detection of uracil-DNA glycosylase (UDG) activity is crucial for clinical diagnosis and prognosis assessment. However, current techniques for accurately monitoring UDG activity still face significant challenges due to the single input or output signal modes. Here, we develop a sequentially activated-dumbbell DNA nanodevice (SEAD) that enables precise and reliable evaluation of UDG activity through primer exchange reactions (PER)-based orthogonal signal output. The SEAD incorporates a double-hairpin structure with a stem containing two deoxyuridine (dU) sites for target recognition and two preblocked primer binding regions for target amplification and signal output. Upon UDG recognition of dU, the SEAD can be cleaved by apurinic/apyrimidinic endonuclease 1 (APE1), generating two different hairpins with exposed primer binding regions. These hairpins serve as templates to initiate the parallel PER, enabling the extending of two different amplification products: a long single-stranded DNA (ssDNA) with repetitive sequences and a short ferrocene-labeled ssDNA with complementary sequences. These products further self-assemble into DNA nano-strings in an orthogonal manner that act as an electrochemiluminescence signal switch, enabling precise detection of low-abundance UDG. This work develops a sequential input and orthogonal output strategy for accurately monitoring UDG activity, highlighting the significant potential in cancer diagnosis and treatment.

Highly catalytic sulfur-doped and bimetal-coordinated CoFe(CN)5NO nanoparticles coupled with PER/HCR amplification cascades for sensitive electrochemical aptamer luteinizing hormone assay

Sensitive monitoring of luteinizing hormone (LH), a glycoprotein that regulates the synthesis of regulatory steroid hormones, can facilitate the diagnosis of various reproductive diseases. In this work, a new and highly catalytic Sulfur-doped and bimetal-coordinated CoFe(CN)5NO (denoted as S-CoFe(CN)5NO) nanoparticles are synthesized. Such material is further used to construct high performance sensing interface and coupled with primer exchange reaction (PER) and hybridization chain reaction (HCR) amplification cascades for sensitive electrochemical aptamer-based LH assay. Target LH molecules bind aptamer sequences in DNA duplex probes to liberate ssDNA strands, which initiate subsequent PER/HCR amplification cascades for the capture of many ferrocene (Fc)-tagged DNAs on sensing interface. S-CoFe(CN)5NO subsequently leads to catalytic oxidation of these Fc tags for yielding substantially magnified currents for realizing ultrasensitive assay of LH with the detection limit of 0.69 pM in range from 5 pM to 10 nM. Owing to the high specificity of aptamer, such sensor has high selectivity and can achieve low levels of LH assay in diluted serum samples. With the successful demonstration for detecting trace LH, such sensor can be easily extended as a universal aptamer-based electrochemical sensing method for monitoring various target analytes in the biomedical and biological fields.

Force-Encoding DNA Nanomachines for Simultaneous and Direct Detection of Multiple Pathogenic Bacteria in Blood

Pathogen detection is growing in importance in the early stages of bacterial infection and treatment due to the significant morbidity and mortality associated with bloodstream infections. Although various diagnostic approaches for pathogen detection have been proposed, most of them are time-consuming, with insufficient sensitivity and limited specificity and multiplexing capability for clinical use. Here, we report a force-encoding DNA nanomachine for simultaneous and high-throughput detection of multiple pathogens in blood through force-induced remnant magnetization spectroscopy (FIRMS). The force-encoding DNA nanomachines coupled with DNA walkers enable analytical sensitivity down to a single bacterium via a cascade signal amplification strategy. More importantly, it allows for rapid and specific profiling of various pathogens directly in blood samples, without being affected by factors such as light color and solution properties. We expect that this magnetic sensing platform holds great promise for various applications in biomedical research and clinical diagnostics.