Journal of Biological Engineering最新文献

Background: Programmed ribosomal frameshifting (PRF) is a translational mechanism that enables the ribosome to shift reading frames and access alternative coding sequences. PRF occurs naturally in a wide range of organisms, including viruses, bacteria, and eukaryotes, where it supports compact encoding and stoichiometric control of protein expression. Despite the great potential of PRF in synthetic circuit designs, a broader adoption of PRF in circuit designs has been hampered by rather strict sequence constraints and structural requirements.

Results: This work introduces a synthetic translational regulatory platform, protein-inducible ribosomal frameshifting (PIRF), by integrating aptamer-protein interactions with a - 1 PRF motif to enable regulated translation in Escherichia coli. PIRF modules respond to intracellular RNA-binding proteins such as PP7 and MS2, triggering frameshifting in a condition-dependent manner. PIRF could be used to program logic gate operations through frame-dependent translation and enable multilayered regulation in synthetic circuits. Further, the flexible PIRF designs enable reading frame-dependent control of fusion protein expression, protein aggregation, and periplasmic localization via strategic positioning of peptide tags and protein coding sequences. While PIRF enabled regulated frameshifting and could be flexibly reconfigured for a variety of circuits and applications, a measurable level of basal frameshifting was often observed, which may require additional strategies for further optimization in the future. Together, PIRF supports applications in programmable and logical control of downstream protein expression, including condition-dependent aggregation and regulated subcellular localization.

Conclusions: PIRF provides a compact and genetically encoded strategy for programmable protein-level regulation, expanding the synthetic biology toolkit for translational control, biosensing and biotherapeutics.

Colorectal cancer (CRC) remains difficult to eradicate locally because chemotherapy, photothermal therapy (PTT), and radiotherapy each have distinct limitations when used alone. Here, we engineer an injectable, mucoadhesive hydrogel-mediated tri-modal nanoplatform designed for localized CRC therapy by integrating smart chemotherapy delivery with externally activatable PTT and radiosensitization. Core-shell AuNP@mesoporous silica nanoparticles were loaded with 5-fluorouracil (5-FU) and functionalized with a pH/ROS-responsive linker and hyaluronic acid (HA) to enable CD44-mediated tumor targeting and microenvironment-triggered "uncapping"/drug release. The targeted nanocarriers were embedded within a chitosan/acellular fish skin (CS/AFS) hydrogel to form a local depot intended to prolong tumor-site residence and reduce systemic exposure. In vitro, the complete nine-group panel demonstrated stepwise gains from targeting, hydrogel confinement, and external activation. The tri-modal condition (Gel-tNP + 808-nm NIR + 2-Gy X-ray) produced the strongest cytotoxicity, approaching near-complete ablation in HCT-116 cells and reproducing the efficacy hierarchy in a second CRC line (SW480), while normal colon epithelial cells (NCM460) maintained higher viability across matched conditions, supporting an initial therapeutic window. Mechanistically, the tri-modal regimen generated the highest intracellular ROS levels, amplified early γH2AX DNA double-strand break signaling and increased damage persistence, and drove extensive cell death consistent with synergistic chemo-photothermal-radiotherapy action (e.g., ~ 9% viability and ~ 5.6-fold LDH release vs. control in the tri-modal group). Collectively, this work advances an engineering framework for localized, externally programmable tri-modal CRC therapy using a stimuli-responsive, HA-targeted nanocarrier embedded in an injectable bioadhesive hydrogel depot.

Background: The repeated emergence of global pandemics has highlighted the urgent need for safe, sustainable, and effective disinfection platforms that eliminate viruses without producing toxic by-products or causing surface damage associated with conventional methods such as ultraviolet irradiation and chemical disinfectants. Here, we present water microdroplet platforms that exploit reactive oxygen species (ROS) spontaneously generated at the air-water interface of micron-sized water droplets, providing a reagent-free and cost-effective approach to viral inactivation. Bacteriophage T7 and lambda (λ), together with MS2 (a non-enveloped RNA bacteriophage) and Phi6 (an enveloped RNA bacteriophage), were selected as model viral systems to evaluate disinfection efficacy across different viral structures.

Results: Water microdroplets with an average diameter of approximately 5 μm, generated by gas nebulization or mesh nebulizers, achieved more than 99.999% viral inactivation within 20 min. Transmission electron microscopy, protein profiling, and DNA analyses revealed that microdroplet-derived ROS disrupted viral capsid integrity and degraded nucleic acids, leading to loss of infectivity. The in situ generation of multiple ROS species was directly confirmed by mass spectrometry using a TEMPO probe and by fluorescence imaging with ROS-sensitive dyes, while scavenger assays verified the ROS-dependent nature of viral inactivation. Practical feasibility was demonstrated by treating fresh produce surfaces such as lettuce and potato, as well as porous and textile materials, resulting in more than 98% viral inactivation without chemical residues.

Conclusions: Together, these results demonstrate that water microdroplets provide an effective, reagent-free, and environmentally benign viral disinfection strategy with broad substrate compatibility for applications in food safety, healthcare, and textile-associated environments.

Articular cartilage injury often leads to vascular endothelial cell (VEC) infiltration, disrupting the microenvironment between cartilage and subchondral bone, thereby compromising cartilage repair quality. Curcumin (Cur) is a natural polyphenol with anti-inflammatory and anti-angiogenic properties that holds promise for therapeutic applications. However, its clinical utility is limited due to poor solubility and instability. To address these challenges, we developed a curcumin-loaded silk fibroin nanoparticle (Cur-SN) delivery system to inhibit VEC infiltration and promote cartilage regeneration. Cur-SNs were prepared and characterised to evaluate their physicochemical properties. The effects of Cur-SN on VEC apoptosis and senescence were assessed, and the underlying mechanism by which Cur-SN regulates mitochondrial homeostasis via the Drp1/ROS pathway was investigated. Additionally, a rat knee cartilage defect model was established, in which Cur-SN combined with a BMSC-loaded hydrogel was implanted. Cartilage differentiation and VEC infiltration levels in newly formed tissues were subsequently analysed. In vitro experiments demonstrated that Cur-SN upregulated Drp1 and ROS levels, leading to mitochondrial homeostasis disruption. This, in turn, induced VEC apoptosis and senescence while significantly inhibited VEC infiltration. Furthermore, Cur-SN effectively counteracted the inhibitory effects of VEC activation on BMSC chondrogenic differentiation. In vivo experiments revealed that Cur-SN reduced VEC infiltration and angiogenesis in newly formed tissues, thereby promoting hyaline cartilage regeneration at the defect site. Cur-SN enhances cartilage repair by upregulating Drp1 expression and ROS levels, thereby disrupting mitochondrial homeostasis, inducing VEC apoptosis and senescence, and inhibiting VEC infiltration.