In Vivo Self-Sorting of Peptides via In Situ Assembly Evolution.

Despite significant progress achieved in artificial self-sorting in solution, operating self-sorting in the body remains a considerable challenge. Here, we report an in vivo self-sorting peptide system via an in situ assembly evolution for combined cancer therapy. The peptide E3C16-SS-EIY consists of two disulfide-connected segments, E3C16SH and SHEIY, capable of independent assembly into twisted or flat nanoribbons. While E3C16-SS-EIY assembles into nanorods, exposure to glutathione (GSH) leads to the conversion of the peptide into E3C16SH and SHEIY, thus promoting in situ evolution from the nanorods into self-sorted nanoribbons. Furthermore, incorporation of two ligand moieties targeting antiapoptotic protein XIAP and organellar endoplasmic reticulum (ER) into the self-sorted nanoribbons allows for simultaneous inhibition of XIAP and accumulation surrounding ER. This leads to the cytotoxicity toward the cancer cells with elevated GSH levels, through activating caspase-dependent apoptosis and inducing ER dysfunction. In vivo self-sorting of E3C16-SS-EIY decorated with ligand moieties is thoroughly validated by tissue studies. Tumor-bearing mouse experiments confirm the therapeutic efficacy of the self-sorted assemblies for inhibiting tumor growth, with excellent biosafety. Our findings demonstrate an efficient approach to develop in vivo self-sorting systems and thereby facilitating in situ formulation of biomedical agents.

Redox Imbalance Triggered Intratumoral Cascade Reaction for Tumor "turn on" Imaging and Synergistic Therapy.

The redox homeostasis in tumors enhances their antioxidant defense ability, limiting reactive oxygen species mediated tumor therapy efficacy. The development of strategies for specific and continuous disruption of the redox homeostasis in tumor cells facilitates the improvement of the cancer therapeutic effect by promoting the apoptosis of tumor cells. Herein, a responsively biodegradable targeting multifunctional integrated nanosphere (HDMn-QDs/PEG-FA) is designed to enhance the anti-tumor efficacy by triggering intratumoral cascade reactions to effectively disrupt intracellular redox homeostasis. Once HDMn-QDs/PEG-FA enters tumor cells, manganese dioxide (MnO2 ) shell on the surface of nanosphere consumes glutathione (GSH) to produce Mn2+ , enabling enhanced chemodynamic therapy (CDT) via a Fenton-like reaction and T1 -weighted magnetic resonance imaging. Meanwhile, the degradation of MnO2 can also cause the fluorescence recovery of quantum dots conjugated on the surface of the shell, realizing "turn-on" fluorescence imaging. In addition, the doxorubicin is released because of the cleavage of the embedded SS bond in the hybrid core framework by GSH. A superior synergistic therapeutic efficiency combined CDT and chemotherapy is shown by HDMn-QDs/PEG-FA in vivo. The tumor-inhibition rate reaches to 94.8% and does not cause normal tissue damage due to the good targeting and tumor microenvironment-specific response.

Immunoprofiling of Severity and Stage of Bacterial Infectious Diseases by Ultrabright Fluorescent Nanosphere-Based Dyad Test Strips.

Bacterial infectious diseases are common clinical diseases that seriously threaten human health, especially in countries and regions with poor environmental hygiene. Due to the lack of characteristic clinical symptoms and signs, it is a challenge to distinguish a bacterial infection from other infections, leading to misdiagnosis and antibiotic overuse. Therefore, there is an urgent need to develop a specific method for detection of bacterial infections. Herein, utilizing ultrabright fluorescent nanospheres (FNs) as reporters, immunochromatographic dyad test strips are developed for the early detection of bacterial infections and distinction of different stages of bacterial infectious diseases in clinical samples. C-reactive protein (CRP) and heparin-binding protein (HBP) are quantified and assayed because their levels in plasma are varied dynamically and asynchronously during the progression of the disease. The detection limits of CRP and HBP can reach as low as 0.51 and 0.65 ng/mL, respectively, due to the superior fluorescence intensity of each FN, which is 570 times stronger than that of a single quantum dot. The assay procedure can be achieved in 22 min, fully meeting the needs of rapid and ultrasensitive detection in the field. This constructed strip has been successfully used to profile the stage and severity of bacterial infections by monitoring the levels of CRP and HBP in human plasma samples, showing great potential as a point-of-care biosensor for clinical diagnosis. In addition to bacterial infections, the developed ultrabright FN-based point-of-care testing can be readily expanded for rapid, quantitative, and ultrasensitive detection of other trace substances in complex systems.

In Situ Self-Sorting Peptide Assemblies in Living Cells for Simultaneous Organelle Targeting.

Self-sorting is a common phenomenon in eukaryotic cells and represents one of the versatile strategies for the formation of advanced functional materials; however, developing artificial self-sorting assemblies within living cells remains challenging. Here, we report on the GSH-responsive in situ self-sorting peptide assemblies within cancer cells for simultaneous organelle targeting to promote combinatorial organelle dysfunction and thereby cell death. The self-sorting system was created via the design of two peptides E3C16E6 and EVMSeO derived from lipid-inspired peptide interdigitating amphiphiles and peptide bola-amphiphiles, respectively. The distinct organization patterns of the two peptides facilitate their GSH-induced self-sorting into isolated nanofibrils as a result of cleavage of disulfide-connected hydrophilic domains or reduction of selenoxide groups. The GSH-responsive in situ self-sorting in the peptide assemblies within HeLa cells was directly characterized by super-resolution structured illumination microscopy. Incorporation of the thiol and ER-targeting groups into the self-sorted assemblies endows their simultaneous targeting of endoplasmic reticulum and Golgi apparatus, thus leading to combinatorial organelle dysfunction and cell death. Our results demonstrate the establishment of the in situ self-sorting peptide assemblies within living cells, thus providing a unique platform for drug targeting delivery and an alternative strategy for modulating biological processes in the future.

Quantum Dots-Based Lateral Flow Test Strip for Glutathione Detection.

Lateral flow test strips (LFTSs) are particularly attractive for assaying targets due to their ability for fast response, simple equipment, portability, and straightforward signal readout. In this work, we describe a rapid and sensitive "off-on" LFTS for point-of-care testing of glutathione (GSH) based on fluorescent quantum dots. Under the optimal conditions, a good linear relationship from 0.1 to 15 µM with a detection limit of 25 nM was obtained, and the whole process was accomplished within 10 min. In addition, this proposed LFTS was successfully used to detect GSH in HeLa cells extract.

A fluorescent nanosphere-based immunochromatography test strip for ultrasensitive and point-of-care detection of tetanus antibody in human serum.

Tetanus still possesses a high infection risk and leads a number of human deaths in poor nations. Point-of-care and ultrasensitive detection of tetanus antibody levels in serum is the key to decrease the risk of tetanus infection and improve the health of people. In this work, by using ultra bright fluorescent nanospheres (FNs) and portable lateral flow test strip (LFTS), a point-of-care and ultrasensitive sensing method has been developed for the detection of tetanus antibodies in human serum. This assay works quite well for tetanus antibodies in the concentration range from 0.0002 to 0.0220 IU/mL with a low detection limit of 0.00011 IU/mL, which is 100-fold lower than conventional gold-based LFTSs. The high sensitivity makes this method suitable for use to detect the low-abundant target in real samples. Besides, this cost-effective FN-based LFTS assay possesses good selectivity, high accuracy, and satisfactory reliability, which holds great potential as a robust candidate for routine medical diagnosis and rapid home testing. Graphical abstract.

A lateral flow assay for the determination of human tetanus antibody in whole blood by using gold nanoparticle labeled tetanus antigen.

The authors describe a lateral flow assay (LFA) for the antibody against the infectious bacterium Clostridium tetani. Gold nanoparticles (AuNPs) were linked to tetanus antigen and are captured in the test line via the formation of a sandwich structure composed of AuNP-labeled tetanus antigen, tetanus antibody, and tetanus antigen. This leads to the formation of a characteristic red line due to the accumulation of AuNPs. The formation of the color line allows for a highly sensitive and selective detection of tetanus antibody, both with bare eyes and by smartphone-based quantitative analysis. This assay offers a wide detection range from 0 to 0.5 IU·mL-1 and has a linear relationship from 0.01 to 0.1 IU·mL-1 with an experimental detection limit of 0.01 IU·mL-1. This assay is simple, fast, inexpensive and highly selective. When applied to the detection of tetanus antibody in spiked whole blood, it provided reliable results that compared well to those obtained with a commercial ELISA kit. Graphical abstract ᅟ.