Efficient Pathogen Capture and Sensing Promoted by Dynamic Deformable Nanointerfaces

Harnessing virus flexibility to selectively capture and profile rare circulating target cells for precise cancer subtyping

The effective isolation of rare target cells, such as circulating tumor cells, from whole blood is still challenging due to the lack of a capturing surface with strong target-binding affinity and non-target-cell resistance. Here we present a solution leveraging the flexibility of bacterial virus (phage) nanofibers with their sidewalls displaying target circulating tumor cell-specific aptamers and their ends tethered to magnetic beads. Such flexible phages, with low stiffness and Young's modulus, can twist and adapt to recognize the cell receptors, energetically enhancing target cell capturing and entropically discouraging non-target cells (white blood cells) adsorption. The magnetic beads with flexible phages can isolate and count target cells with significant increase in cell affinity and reduction in non-target cell absorption compared to magnetic beads having rigid phages. This differentiates breast cancer patients and healthy donors, with impressive area under the curve (0.991) at the optimal detection threshold (>4 target cells mL-1). Immunostaining of captured circulating tumor cells precisely determines breast cancer subtypes with a diagnostic accuracy of 91.07%. Our study reveals the power of viral mechanical attributes in designing surfaces with superior target binding and non-target anti-fouling.

Phage-displayed heptapeptide sequence conjugation significantly improves the specific targeting ability of antimicrobial peptides against Staphylococcus aureus

Broad-spectrum antibacterial drugs often lack specificity, leading to indiscriminate bactericidal activity, which can disrupt the normal microbial balance of the host flora and cause unnecessary cytotoxicity during systemic administration. In this study, we constructed a specifically targeted antimicrobial peptide against Staphylococcus aureus by introducing a phage-displayed peptide onto a broad-spectrum antimicrobial peptide and explored its structure-function relationship through one-factor modification. SFK2 obtained by screening based on the selectivity index and the targeting index showed specific killing ability against S. aureus. Moreover, SFK2 showed excellent biocompatibility in mice and piglet, and demonstrated significant therapeutic efficacy against S. aureus infection. In conclusion, our screening of phage-derived heptapeptides effectively enhances the specific bactericidal ability of the antimicrobial peptides against S. aureus, providing a theoretical basis for developing targeted antimicrobial peptides.

M13 phage: a versatile building block for a highly specific analysis platform

Viruses are changing the biosensing and biomedicine landscape due to their multivalency, orthogonal reactivities, and responsiveness to genetic modifications. As the most extensively studied phage model for constructing a phage display library, M13 phage has received much research attention as building blocks or viral scaffolds for various applications including isolation/separation, sensing/probing, and in vivo imaging. Through genetic engineering and chemical modification, M13 phages can be functionalized into a multifunctional analysis platform with various functional regions conducting their functionality without mutual disturbance. Its unique filamentous morphology and flexibility also promoted the analytical performance in terms of target affinity and signal amplification. In this review, we mainly focused on the application of M13 phage in the analytical field and the benefit it brings. We also introduced several genetic engineering and chemical modification approaches for endowing M13 with various functionalities, and summarized some representative applications using M13 phages to construct isolation sorbents, biosensors, cell imaging probes, and immunoassays. Finally, current issues and challenges remaining in this field were discussed and future perspectives were also proposed.