No abstract

Cyclic peptides are important natural products and hold great promise for the identification of new bioactive molecules. The split‐intein‐mediated SICLOPPS technology provides a generic access to fully genetically encoded head‐to‐tail cyclized peptides and large libraries thereof (SICLOPPS=split‐intein circular ligation of peptides and proteins). However, owing to the spontaneous protein splicing reaction, product formation occurs inside cells, making peptide isolation inconvenient and precluding traditional in vitro assays for inhibitor discovery. The design of a genetically encoded, light‐dependent intein using the photocaged tyrosine derivative ortho‐nitrobenzyltyrosine incorporated at an internal, non‐catalytic position is now reported. Stable intein precursors were purified from the E. coli expression host and subsequently subjected to light activation in vitro for both the regular protein splicing format and cyclic peptide production, including the natural product segetalin H as an example. The activity of the intein could also be triggered in living cells.

No abstract

Cancer cells generate and secrete diverse molecules into circulation that could be used as signatures for health and disease. A significant obstacle in detecting such molecules derives from their low signal-to-noise ratio in subsequent downstream analyses. Developing reliable tools and methods for cancer early detection is crucial for advancing global strategies to decrease mortality, monitor disease progression and therapy, and improve the quality of life of patients. This perspective critically addresses recent developments in cancer early detection, highlighting current trends in the enrichment of cancer-related biomarkers, dividing them into biochemical and biophysical methods. Finally, we provide insights into the challenges and opportunities in biomarker isolation and enrichment protocols. Integrating these methods into clinical decision-making pipelines could lead to a better understanding of cancer progression, treatment efficacy, and hence improving the medical outcomes for cancer patients.

Stroke is the second top leading cause of death globally. It is caused by an abrupt interruption of blood flow to the brain. In that course, brain natriuretic peptide (BNP) and its derivative N-terminal pro b-type natriuretic peptide (NT-proBNP), neurohormones produced mainly by the heart ventricles in response to excessive stretching of cardiomyocytes (heart muscle cells), are proven to be good biomarkers for heart failure diagnosis. Moreover, there is growing clinical interest of the use of NT-proBNP for stroke diagnosis and prognosis because it is significantly associated with cardioembolic stroke and secondary stroke reoccurrence, with sensitivity >90% and specificity >80%. However, in diagnostic settings, there is still a need to address the encountered analytical problems, particularly assay specificity and set up. In this study, a novel approach for NT-proBNP detection is demonstrated using an electrochemical immunoassay method. A label-free impedimetry immunosensor for stroke biomarker was developed using modified disposable screen-printed gold electrodes (SPGE) hosting specific anti-NT-proBNP capture antibody. The performance of our immunosensor was studied in the presence of NT-proBNP in both buffered and mock (porcine) plasma samples. A linear relation between the relative total resistance (ΔRtot) responses and the NT-proBNP concentrations in buffer was observed in a range from 0.1 to 5 ng mL-1 with a correlation coefficient (R2) of 0.94656. Overall, the biosensor has demonstrated the capability to quantitate NT-proBNP and differentiate such concentrations in a low concentration range, especially among 0, 0.1, 0.5, 1, and 3 ng mL-1 in plasma samples within 25 min. This range is valuable not only for classifying cardioembolic stroke (higher or equal to 0.5 ng mL-1), but also predicting the risk of secondary stroke reoccurrence (higher than 0.255 ng mL-1). Our biosensor has the potential to be used as an easy-to-use point-of-care test that is both accurate and affordable.

Health relevant information is coded in circulating signatures or biomarkers, such as the secretome, extracellular vesicles, nucleic acids, bacteria, and other markers. [1][2][3] The collection and analysis of such signatures can serve as an early sign of disease initiation and its progression through repeated sampling. [4][5][6][7][8][9][10] Nevertheless, it remains a challenge to isolate or sample biomarkers from regions of the body with limited accessibility, such as the gastrointestinal (GI) tract, which is more than 9 meters in total length. [11,12] To gain access to these challenging locations, invasive medical procedures, such as surgery, biopsies, and colonoscopies, are required to extract information, limiting the repeatability of such measurements. [13][14][15] These techniques involve trained practitioners, expensive instruments, and specialized facilities, making them hard to expand to a large population. In contrast, minimally invasive approaches can also be used for sampling biomarkers. [16] For instance, liquid biopsy is a standard approach to obtain a snapshot of the signature pool from biofluids (blood, urine, or stool samples). [17,18] Although useful, liquid biopsy frequently provides indirect data that is averaged across the sample and not specific to a particular region of the body.Smart pills have been deployed as a method to investigate cavities inside the body. [19][20][21][22][23][24] For instance, the PillCam, an ingestible capsule with an embed camera, is commonly used to search for polyps in the GI. [25][26][27][28][29][30][31][32][33] More recently, smart pills have been applied to capture and sense biomarkers through lab-on-a-chip systems, [26][27][28] osmotic gradients, [29] and passive absorption in refs. [30][31][32] methods. The ability to isolate biomarkers within localized environments

Liquid biopsy has garnered considerable attention as a complementary clinical tool for the early detection, molecular characterization and monitoring of cancer over the past decade. In contrast to traditional solid...

The ability to self-test for HIV is vital to preventing transmission, particularly when used in concert with HIV biomedical prevention modalities, such as pre-exposure prophylaxis (PrEP). In this paper, we review recent developments in HIV self-testing and self-sampling methods, and the potential future impact of novel materials and methods that emerged through efforts to develop more effective point-of-care (POC) SARS-CoV-2 diagnostics. We address the gaps in existing HIV self-testing technologies, where improvements in test sensitivity, sample-to-answer time, simplicity, and cost are needed to enhance diagnostic accuracy and widespread accessibility. We discuss potential paths toward the next generation of HIV self-testing through sample collection materials, biosensing assay techniques, and miniaturized instrumentation. We discuss the implications for other applications, such as self-monitoring of HIV viral load and other infectious diseases.