DNA-induced fusion between lipid domains of peptide-lipid hybrid vesicles

Shear Stress-Responsive Peptide Cubic Vesicles Assembled from Membranes with Different Curvatures

Stenotic blood vessels differ from normal blood vessels in that the blood flow shear stress is increased to a higher order of magnitude. Therefore, drug delivery systems (DDSs) capable of responding to changes in the shear stress are highly desirable. To prepare sheer stress-responsive carriers, a peptide cubic vesicle (PCV) is prepared by combining two types of sheet-forming amphiphilic polypeptides: planar sheet-forming GA-(PSar)10-b-(l-Leu-Aib)6-b-(PSar)10-GA (S10L12S10) and curved sheet-forming GA-(PSar)24-b-(l-Leu-Aib)7 (S26L14), which GA, PSar, Leu and Aib mean glycolic acid, polysarcosine, leucine and α-aminoisobutyric acid. The PCV is successfully constructed from a mixture of S10L12S10 and S26L14 in molar ratios of 2:1 and 1:1. In addition, curved S26L14 membrane forms edges and corners, while planar S10L12S10 membrane forms the faces of the PCV. Notably, the PCV deforms under pathological shear stress conditions (10 Pa) but retains its original structure under the normal physiological shearing force of 1 Pa. Moreover, the PCV releases 84% of its encapsulated cargo in response to simulated pathological flow. Targeting the changing biophysical environment for drug development has the potential to shift the paradigm for treating vascular occlusion-inducing diseases from biochemical to mechanical stimulation, thereby lowering the required dose and side effects of drugs while maximizing their therapeutic efficacy.

Rapid in situ mutation detection in extracellular vesicle DNA

Aim: A PCR- and sequencing-free mutation detection assay facilitates cancer diagnosis and reduces over-reliance on specialized equipment. This benefit was highlighted during the pandemic when high demand for viral nucleic acid testing often sidelined mutation analysis. This shift led to substantial challenges for patients on targeted therapy in tracking mutations. Here, we report a 30-min DNA mutation detection technique using Cas12a-loaded liposomes in a microplate reader, a fundamental laboratory tool. Methods: CRISPR-Cas12a complex and fluorescence-quenching (FQ) probes are introduced into tumor-derived extracellular vesicles (EV) through membrane fusion. When CRISPR-RNA hybridizes with the DNA target, activated Cas12a can trans-cleave FQ probes, resulting in fluorescence signals for the quantification of DNA mutation. Results: This method enables the detection of EGFR L858R mutation in EV DNA within 30 min. Laborious extraction, purification, and other preparation steps for EV DNA are eliminated. The need for advanced data processing is also dispensed with. In a cohort study involving 10 healthy donors and 30 patients with advanced non-small cell lung cancer (NSCLC), the assay achieved a sensitivity of 86.7%, a specificity of 90%, and an accuracy of 87.5%. Conclusion: The limit of detection of our Cas12 assay was ~ 8 × 105 EVs, corresponding to a mutation allele frequency (MAF) of ~ 10%. The MAF in late-stage cancers varies widely but often falls within 5%-50%. Therefore, without amplification of targets, this Cas12 assay can detect mutations in patients with advanced lung cancer. Future advancements in multiplex and high-throughput mutation detection using this assay will streamline self-diagnosis and treatment monitoring at home.

Chimeric nanobody-decorated liposomes by self-assembly

Liposomes as drug vehicles have advantages, such as payload protection, tunable carrying capacity and improved biodistribution. However, due to the dysfunction of targeting moieties and payload loss during preparation, immunoliposomes have yet to be favoured in commercial manufacturing. Here we report a chemical modification-free biophysical approach for producing immunoliposomes in one step through the self-assembly of a chimeric nanobody (cNB) into liposome bilayers. cNB consists of a nanobody against human epidermal growth factor receptor 2 (HER2), a flexible peptide linker and a hydrophobic single transmembrane domain. We determined that 64% of therapeutic compounds can be encapsulated into 100-nm liposomes, and up to 2,500 cNBs can be anchored on liposomal membranes without steric hindrance under facile conditions. Subsequently, we demonstrate that drug-loaded immunoliposomes increase cytotoxicity on HER2-overexpressing cancer cell lines by 10- to 20-fold, inhibit the growth of xenograft tumours by 3.4-fold and improve survival by more than twofold.

Rapid in situ mutation detection in extracellular vesicle-DNA

A PCR- and sequencing-free mutation detection assay facilitates cancer diagnosis and reduces over-reliance on specialized equipment. This benefit was highlighted during the pandemic when high demand for viral nucleic acid testing often sidelined mutation analysis. This shift led to substantial challenges for patients on targeted therapy in tracking mutations. Here, we report a 30-minute DNA mutation detection technique using Cas12a-loaded liposomes in a microplate reader, a fundamental laboratory tool. CRISPR-Cas12a complex and fluorescence-quenching (FQ) probes are introduced into tumor-derived extracellular vesicles (EV) through membrane fusion. When CRISPR-RNA hybridizes with the DNA target, activated Cas12a can trans-cleave FQ probes, resulting in fluorescence signals for the quantification of DNA mutation. Future advancements in multiplex and high-throughput mutation detection using this assay will streamline self-diagnosis and treatment monitoring at home.

Polysarcosine-Coated liposomes attenuating immune response induction and prolonging blood circulation

HYPOTHESIS

Liposomes coated with long polysarcosine (PSar) chains at a high density might enable long blood circulation and attenuate accelerated blood clearance (ABC) phenomenon.

EXPERIMENTS

In this study, we controlled the length (23, 45, 68 mers) and density (5, 10, 15 mol%) of PSar on liposomal coatings and, furthermore, investigated the effects of PSar length and density on the blood circulation time, biodistribution, immune response, and ABC phenomenon induction. Length-controlled PSar-bound lipids (PSar-PEs) were synthesized using a click reaction and inserted into bare liposomes at different combinations of chain lengths and proportions.

FINDINGS

Although all PSar-coated liposomes (PSar-lipos) had similar morphological, physical, and chemical properties, they had different blood circulation times and biodistribution, and exerted varied effects on the immune system. All PSar-lipos with different PSar length and density showed a similar anti-PSar IgM response. Liposomes modified with the longest PSar chain (68 mers) at a high density (15 mol%) showed the longest blood circulation time and, additionally, attenuated ABC phenomenon compared with PEG-lipo. The ex vivo analysis of the biodistribution of liposomes revealed that a thick PSar layer enhanced the blood circulation time of liposomes due to the reduction of the accumulation of liposomes in the liver and spleen. These findings provide new insights into the relationship between IgM expression and ABC phenomenon inhibition.

Peptide-lipid hybrid vesicles with stimuli-responsive phase separation for controlled membrane functions

A disulfide-tethered peptide-lipid conjugate self-assembled into a homogeneously distributed peptide-lipid hybrid vesicle. Upon dithiothreitol treatment, the homogeneous peptide-lipid membrane spontaneously divided into lipid-rich and peptide-rich domains, while the vesicle retained its size and shape. Membrane phase separation enhanced temperature-dependent cargo release.

Tuning the Extracellular Vesicles Membrane through Fusion for Biomedical Applications

Membrane fusion is one of the key phenomena in the living cell for maintaining the basic function of life. Extracellular vesicles (EVs) have the ability to transfer information between cells through plasma membrane fusion, making them a promising tool in diagnostics and therapeutics. This study explores the potential applications of natural membrane vesicles, EVs, and their fusion with liposomes, EVs, and cells and introduces methodologies for enhancing the fusion process. EVs have a high loading capacity, bio-compatibility, and stability, making them ideal for producing effective drugs and diagnostics. The unique properties of fused EVs and the crucial design and development procedures that are necessary to realize their potential as drug carriers and diagnostic tools are also examined. The promise of EVs in various stages of disease management highlights their potential role in future healthcare.