Biology subjects

Chua, S. L.

Publications and source records attributed to Chua, S. L..

4 recordsLinked to original sources

bioRxiv2025

Engineering magnetically guided bacteriophages for precision antimicrobial therapy and targeted biofilm eradication

Viruses, including bacteriophages, rely on passive diffusion to reach their hosts, limiting the efficacy of virus-based therapies and leading to off-target accumulation with systemic effects. Here, we present a strategy to confer controllable motility to bacteriophages by incorporating iron nanoparticles (FeNPs) into their head structures while preserving infectivity. Cryo-electron microscopy (Cryo-EM) and transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) confirmed the FeNP presence in the phages head. FeNP-tagged phages can be magnetically enriched and isolated from bacterial prey cultures, eliminating the need for ultracentrifugation. Under magnetic guidance, these engineered phages exhibit rapid and directed movement through complex microenvironments, including mazes and polymer barriers, enabling precise bacterial targeting and biofilm eradication in a microfluidic system. In an in vivo wound infection model, magnetically guided phages successfully navigated from the peritoneum to the biofilms on the wound, thus selectively eliminating biofilms while minimizing systemic exposure to other organs. Hence, our approach confers viral mobility, thus enhancing the precision and efficacy of bacteriophage-based biotechnological and therapeutic applications.

microbiology↗

bioRxiv2025

Microbial biofilm matrix restricts phagocytic cells motility in a 3D-microfluidics phagocyte migration model

Understanding how immune cells navigate complex microbial environments requires models that integrate biophysical and biological realism. However, the microscale mechanisms underlying phagocyte migration on pathogenic biofilms remain poorly understood, and there remains a lack of experimental models for study of 3D-interactions between host cells and biofilms. Here, we present a multiscale microfluidic secondary-infection-on-a-chip incorporating human-cell-based model or an ex vivo perfused porcine skin system, to study macrophage migration across bacterial biofilms under controlled flow and spatial confinement. Using Pseudomonas aeruginosa as model pathogen, we demonstrated that biofilm matrix components, specifically the exopolysaccharide Psl, physically impede macrophage motility and directional persistence. Exopolysaccharide-deficient mutants allowed near-normal macrophage migration. Persistent random walk (PRW) simulation modeling recapitulated these motility dynamics, revealing altered migration coefficients within biofilm matrices. Consistent with cell-based model, biofilms impede macrophages on the skin tissue. Hence, our results establish an experimental and modelling framework for studying physical constraints in host-pathogen interactions, providing new insights into mechanical and spatial barriers that shape immune responses to biofilm infections.

microbiology↗

bioRxiv2023

Dual-species proteomics and targeted intervention of animal-pathogen interactions

Complexity in host-pathogen interactions drives the need to develop sensitive and accurate biochemical techniques to elucidate host and pathogen protein expressions. Current proteomics techniques reveal information from the point of view of either the host or pathogen, but do not provide data on the corresponding partner. While dual-species transcriptomics is increasingly used to study RNA expression in host and pathogen, it remains challenging to simultaneously study host-pathogen proteomes that reflect the direct competition between host and pathogen. Using Caenorhabditis elegans-Pseudomonas aeruginosa infection model as proof-of-concept, we established a forward+reverse SILAC proteomics approach to simultaneously label and quantify newly-expressed proteins of host and pathogen without physical isolation. We observed iron competition between pathogen iron scavenger and host iron uptake protein, where P. aeruginosa upregulated pyoverdine synthesis protein (PvdA) and secreted pyoverdine, and C. elegans expressed ferritin (FTN-2) respectively. Using Galangin as a novel PvdA inhibitor identified by structure-based virtual-screening, targeted intervention of iron competition eliminated P. aeruginosa infection, and enabled animal survival. Our work provides insights into the mechanisms dictating host-pathogen interactions and offers novel strategies for anti-infective therapy.

biochemistry↗

bioRxiv2017

Cyclic-di-GMP is required for corneal infection by Pseudomonas aeruginosa and modulates host immunity

Biofilms are extremely tolerant toward antimicrobial treatment and host immune clearance due to their distinct physiology and protection by extracellular polymeric substances. Bis-(3{acute}-5{acute})-cyclic dimeric guanosine monophosphate (c-di-GMP) is an essential messenger that regulates biofilm formation by a wide range of bacteria. However, there is a lack of physiological characterization of biofilms in vivo as well as the roles of c-di-GMP signaling in mediating host-biofilm interactions. Here, we employed dual RNA-Seq to characterize the host and pathogen transcriptomes during Pseudomonas aeruginosa infection using a mouse keratitis model. In vivo P. aeruginosa biofilms maintained a distinct physiology compared with in vitro P. aeruginosa biofilms, with enhanced virulence and iron uptake capacity. C-di-GMP synthesis was enhanced in P. aeruginosa cells in vivo, potentially due to down-regulation of the expression of several phosphodiesterases (e.g., DipA, NbdA). Increased intracellular c-di-GMP levels were required for long-term ocular colonization of P. aeruginosa and impaired host innate immunity.

microbiology↗