A smart multiantenna gene theranostic system based on the programmed assembly of hypoxia-related siRNAs

The systemic therapeutic utilisation of RNA interference (RNAi) is limited by the non-specific off-target effects, which can have severe adverse impacts in clinical applications. The accurate use of RNAi requires tumour-specific on-demand conditional activation to eliminate the off-target effects of RNAi, for which conventional RNAi systems cannot be used. Herein, a tumourous biomarker-activated RNAi platform is achieved through the careful design of RNAi prodrugs in extracellular vesicles (EVs) with cancer-specific recognition/activation features. These RNAi prodrugs are assembled by splitting and reconstituting the principal siRNAs into a hybridisation chain reaction (HCR) amplification machine. EVs facilitate the specific and efficient internalisation of RNAi prodrugs into target tumour cells, where endogenous microRNAs (miRNAs) promote immediate and autonomous HCR-amplified RNAi activation to simultaneously silence multiantenna hypoxia-related genes. With multiple guaranteed cancer recognition and synergistic therapy features, the miRNA-initiated HCR-promoted RNAi cascade holds great promise for personalised theranostics that enable reliable diagnosis and programmable on-demand therapy.

Programmed assembly of bespoke prototissues on a microfluidic platform

The precise assembly of protocell building blocks into prototissues that are stable in water, capable of sensing the external environment and which display collective behaviours remains a considerable challenge in...

Programmed Assembly of Bespoke Prototissue Spheroids on a Microfluidic Platform

<p>The precise assembly of protocell building blocks into prototissues that are stable in water, capable of sensing the external environment and which display collective behaviours remains a considerable challenge in prototissue engineering. In this work we explore the use of microfluidic technologies for the programmed assembly of bio-orthogonally reactive protein-polymer protocells into prototissue spheroids of precise size, composition and with unique Janus configurations. We then show that by controlling the number and phenotype of the protocells that compose the prototissue spheroids it is possible to modulate both the amplitude of the thermally induced contractions of the biomaterial and its collective endogenous biochemical reactivity. Overall, our results show that microfluidic technologies enable a new route to the precise and high-throughput fabrication of tissue-like materials with programmable collective properties that can be tuned through a careful assembly of protocell building blocks of different phenotypes. We anticipate that our bespoke prototissues will be a starting point for the development of more sophisticated artificial tissues for use in medicine, soft robotics and environmentally beneficial bioreactor technologies.</p>

Programmed Assembly of Bespoke Prototissue Spheroids on a Microfluidic Platform

<p>The precise assembly of protocell building blocks into prototissues that are stable in water, capable of sensing the external environment and which display collective behaviours remains a considerable challenge in prototissue engineering. In this work we explore the use of microfluidic technologies for the programmed assembly of bio-orthogonally reactive protein-polymer protocells into prototissue spheroids of precise size, composition and with unique Janus configurations. We then show that by controlling the number and phenotype of the protocells that compose the prototissue spheroids it is possible to modulate both the amplitude of the thermally induced contractions of the biomaterial and its collective endogenous biochemical reactivity. Overall, our results show that microfluidic technologies enable a new route to the precise and high-throughput fabrication of tissue-like materials with programmable collective properties that can be tuned through a careful assembly of protocell building blocks of different phenotypes. We anticipate that our bespoke prototissues will be a starting point for the development of more sophisticated artificial tissues for use in medicine, soft robotics and environmentally beneficial bioreactor technologies.</p>

Asymmetrizing an icosahedral virus capsid by hierarchical assembly of subunits with designed asymmetry

Symmetrical protein complexes are ubiquitous in natural biological systems. Many have been reengineered in vitro for chemical and medical applications. Symmetrical viral capsids and their assembly are frequent platforms for these investigations. Lacking a means to create asymmetric capsids may limit broader applications. Here, starting with the homodimeric Hepatitis B Virus capsid protein, we developed a heterodimer, designed a hierarchical assembly pathway, and produced asymmetric capsids. We showed that the heterodimers assemble into hexamers, and such preformed hexamers can nucleate co-assembly, leading to “Janus” capsids with two discrete patches. We removed the hexamer patches specifically and observed asymmetric holey capsids by cryo-EM reconstruction. The resulting holes can be refilled with new engineered dimers. This programmed assembly pathway provides windows for specific engineering and modification inside and outside of the capsid. This strategy can also be generalized to other capsid assembly systems.