The discovery and enhanced properties of trichain lipids in lipopolyplex gene delivery systems

Cationic lipid modification of DNA tetrahedral nanocages enhances their cellular uptake

Self-assembled DNA nanocages are among the most promising candidates for bioimaging and payload delivery into cells. DNA nanocages have great potential to efficiently address drug resistance and nucleic acid delivery problems due to precise control of their shape and size, and excellent biocompatibility. Although DNA nanostructures demonstrate some cellular uptake, because they bear a highly negative charge, the uptake of tetrahedral nanostructures is hindered by electrostatic repulsion. In this study, we describe a method to enhance the cellular uptake of DNA nanostructures using a binary system containing DNA and a positively charged head group with a hydrophobic lipid chain containing lipids for cellular internalization. Here we represent the functionalization of a model cage, DNA tetrahedron (TD) with a cationic lipid, N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA). Atomic force microscopy (AFM) and other standard characterization techniques were used to explore the co-assembly of the DNA tetrahedron and DOTMA. We revealed a simple confocal microscopy-based approach to show the enhancement in the cellular uptake of DNA nanocages. This new method will find multiple applications in delivery applications such as gene transfection, drug delivery and targeted bioimaging.

Integrated radiochemotherapy study of ZIF-8 coated with osteosarcoma-platelet hybrid membranes for the delivery of Dbait and Adriamycin

Introduction: The toxic side effects of systemic high-dose chemotherapy and poor sensitivity to radiotherapy hinder the survival rate of patients with osteosarcoma (OS). Nanotechnology offers new solutions for OS treatment; however, conventional nanocarriers suffer from inadequate targeting of tumors and short in vivo circulation time. Methods: Here, we designed a novel drug delivery system, [Dbait-ADM@ZIF-8]OPM, which uses OS-platelet hybrid membranes to encapsulate nanocarriers, to enhance the targeting and circulation time of nanocarriers, thereby enabling high enrichment of the nanocarriers in OS sites. Results: In the tumor microenvironment, the pH-sensitive nanocarrier, which is the metal-organic framework ZIF-8, dissociates to release radiosensitizer Dbait and the classical chemotherapeutic agent Adriamycin for the integrated treatment of OS via radiotherapy and chemotherapy. Benefiting from the excellent targeting ability of the hybrid membrane and the outstanding drug loading capacity of the nanocarrier, [Dbait-ADM@ZIF-8]OPM showed potent anti-tumor effects in tumor-bearing mice with almost no significant biotoxicity. Conclusion: Overall, this project is a successful exploration of the combination of radiotherapy and chemotherapy of OS treatment. Our findings solve the problems of the insensitivity of OS to radiotherapy and the toxic side effects of chemotherapy. Furthermore, this study is an expansion of the research of OS nanocarriers and provides new potential treatments for OS.

Stability testing of the Pfizer-BioNTech BNT162b2 COVID-19 vaccine: a translational study in UK vaccination centres

Objective

The roll-out of the Pfizer-BioNTech BNT162b2 COVID-19 vaccine has brought many logistical challenges, such as the absence of comprehensive stability data leading to strict handling instructions during dilution and administration. Accidental mishandling therefore presents challenging clinical dilemmas, which often led vaccine providers to err on the side of caution and discard mishandled vials rather than risk administering ineffective vaccine. This study aims to answer key questions about the vaccine's stability to allow for a more informed decision-making process should a non-conformity occur.

Methods

Residual vaccine in freshly used, but appropriately stored vials collected from vaccination centres in Brighton, UK, were tested after exposure to various handling conditions and analysed by dynamic light scattering to determine the size of the lipid-mRNA nanoparticles, and gel electrophoresis to visualise the mRNA integrity and separation from the lipid formulation.

Results

Knocking or dropping vaccine samples from small heights resulted in lowest levels of instability, indicating low risk of compromising clinical efficacy. However, repeated drawing and injecting through 23 G needles at high speed and, more significantly, shaking and vortexing led to progressive increase in the size and polydispersity index of the lipid-mRNA nanoparticles, coupled with or caused by up to ~50% release of mRNA from the lipid formulation. This is thought to impact the vaccine's efficacy due to lack of free mRNA protection and cellular internalisation.

Conclusions

These results reiterate the importance of adhering to the manufacturer's instructions on handling, especially with regard to shaking and exposing the vaccine to excessive vibration.

Drug delivery, biodistribution and anti-EGFR activity: theragnostic nanoparticles for simultaneous in vivo delivery of tyrosine kinase inhibitors and kinase activity biosensors

In vivo delivery of small molecule therapeutics to cancer cells, assessment of the selectivity of administration, and measuring the efficacity of the drug in question at the molecule level, are important ongoing challenges in developing new classes of cancer chemotherapeutics. One approach that has the potential to provide targeted delivery, tracking of biodistribution and readout of efficacy, is to use multimodal theragnostic nanoparticles to deliver the small molecule therapeutic. In this paper, we report the development of targeted theragnostic lipid/peptide/DNA lipopolyplexes. These simultaneously deliver an inhibitor of the EGFR tyrosine kinase, and plasmid DNA coding for a Crk-based biosensor, Picchu-X, which when expressed in the target cells can be used to quantify the inhibition of EGFR in vivo in a mouse colorectal cancer xenograft model. Reversible bioconjugation of a known analogue of the tyrosine kinase inhibitor Mo-IPQA to a cationic peptide, and co-formulation with peptides containing both EGFR-binding and cationic sequences, allowed for good levels of inhibitor encapsulation with targeted delivery to LIM1215 colon cancer cells. Furthermore, high levels of expression of the Picchu-X biosensor in the LIM1215 cells in vivo allowed us to demonstrate, using fluorescence lifetime microscopy (FLIM)-based biosensing, that EGFR activity can be successfully suppressed by the tyrosine kinase inhibitor, released from the lipopolyplexes. Finally, we measured the biodistribution of lipopolyplexes containing 125I-labelled inhibitors and were able to demonstrate that the lipopolyplexes gave significantly higher drug delivery to the tumors compared with free drug.

Novel α-tocopherol-ferrocene conjugates for the specific delivery of transgenes in liver cancer cells under high serum conditions

The delivery of therapeutic genes to a specific organ has drawn significant research attention. Among the pool of various delivery vectors, cationic liposomes (non-viral) are potential candidates for delivering therapeutic genes due to their low immunogenic response. Here, we have developed novel ferrocene-conjugated cationic tocopheryl aggregates as non-viral vectors. These formulations can transfer a reporter gene (pGL3; encoded for luciferase protein) specifically to liver cancer cells (HepG2 and Huh7) instead of non-hepatic cancer cells, such as Caco-2 (human colon carcinoma) and HeLa (cervical cancer) cells. The transfection efficiency (TE) of the optimum liposomal formulation is more significant than commercially available Lipofectamine 2000 (L2K). Notably, it retains its TE under high serum conditions (up to 50% FBS). A coupled effect from conjugated ferrocene and tocopherol in the cationic liposomal formulation might be responsible for the cell-specific delivery and higher serum compatibility. Therefore, the present proposed delivery system may provide a platform for further progress in terms of developing hepatotropic gene delivery systems.

Sunlight-Mediated Thiol-Ene/Yne Click Reaction: Synthesis and DNA Transfection Efficiency of New Cationic Lipids

The design of green synthetic reaction conditions is very challenging, especially for biomaterials, but worthwhile if the compounds can be easily synthesized in the aqueous medium. Herein, we report the development of sunlight-mediated thiol-ene/yne click reaction in the presence of a catalytic amount of tert-butyl hydroperoxide (TBHP) in an aqueous medium. The optimized reaction conditions were successfully applied to synthesize a series of small molecules and lipids in a single step in the aqueous medium. The synthetic cationic lipid/co-lipid formed positively charged stable nanosized liposomes that effectually bind with the genetic materials. The in vitro DNA transfection and cellular uptake assays showed that the synthesized cationic lipids have comparable efficiency to commercially available Lipofectamine 2000. This mild synthetic strategy can also be used for smart design of novel or improvement of prevailing lipid-based nonviral gene delivery systems. Such chemical transformations in the aqueous medium are more environment-friendly than other reported thiol-ene/yne click reactions performed in an organic solvent medium.