Monitoring the in vivo siRNA release from lipid nanoparticles based on the fluorescence resonance energy transfer principle

Iterative Screening of Vitamin E-Based Functional Lipid Nanoparticles for mRNA Delivery

Ionizable lipids are crucial for the effective delivery of mRNA by using lipid nanoparticles (LNPs). Endowing ionizable lipids with tailored biological properties could potentially augment the therapeutic efficacy of mRNA-based treatments. Herein, a functional vitamin E (VE)-based lipid library with distinct head groups was designed and synthesized. Due to the presence of VE, these lipids inherently exhibited immunomodulatory properties, including the promotion of cellular uptake, dendritic cells maturation, and antigen presentation. Through iterative optimization of the LNP components and the architecture of ionizable lipids, the correlation between the structure of ionizable lipids and their mRNA delivery efficiency has been established, leading to the finding of the most effective delivery formulation. Benefiting from the high mRNA delivery efficiency and the immunomodulatory function of LNPs themselves, VE-based LNPs have demonstrated complete remission in colon cancer by delivering mIL-12, which offered a beneficial combination with immune checkpoint blockade. The proposed functional LNPs were anticipated to furnish potential delivery systems for mRNA-based cancer treatments.

Development of Small Interfering RNA Loaded Cationic Lipid Nanoparticles for the Treatment of Liver Cancer with Elevated α-Fetoprotein Expression

α-Fetoprotein (AFP) is an oncogenic glycoprotein that is overexpressed in most patients with liver cancer. Moreover, it significantly affects tumorigenesis and progression, particularly by inhibiting programmed cell death or apoptosis. The treatment of liver cancer with chemotherapy is currently still in use, but its toxicity is a major concern. Alternatively, targeted therapy, especially small interfering RNA (siRNA)-based therapeutics that utilize siRNA to suppress target gene expression, is a promising cancer treatment approach that can help reduce such drawbacks. However, transporting siRNA into cells is a challenge due to its ease of degradation and limited cell membrane permeability. To overcome this limitation, we fabricated cationic lipid nanoparticles (cLNPs) to deliver AFP-targeted siRNA (siAFP) to AFP-producing liver cancer cells. Our results illustrated that these nanoparticles had a high capacity for siRNA encapsulation (>95%) and entered the cancer cells efficiently. Cell internalization of siAFP-loaded cLNPs resulted in the silencing of AFP mRNA expression and led to increased apoptotic cell death by inducing caspase-3/7 activity. This suggested that our cLNPs could be used as a powerful siRNA delivery carrier and siAFP-loaded cLNPs might be a useful strategy for treating liver cancer in the future.

Capturing the dynamic integrity of carbocyanine fluorophore-based lipid nanoparticles using the FRET technique

Nanoparticles capable of dynamically reporting their structural integrity in real-time are a powerful tool to guide the design of drug delivery technologies. Lipid nanoparticles (LNPs) offer multiple important advantages for drug delivery, including stability, protection of active substances, and sustained release capabilities. However, tracking their structural integrity and dynamic behaviour in complex biological environments remains challenging. Here, we report the development of a Förster resonance energy transfer (FRET)-enabled LNP platform that achieves unprecedented sensitivity and precision in monitoring nanoparticle disintegration. The FRET-based LNPs were prepared using nanoprecipitation, encapsulating high levels of 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO) and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) fluorophores as the donor and acceptors, respectively. The resulting LNPs had a mean diameter of 114 ± 19 nm with a distinct FRET signal. An optimal energy transfer efficiency of 0.98 and an emission quantum yield of 0.13 were achieved at 11.1% fluorophore loading in the LNPs, balancing efficient energy transfer and minimal aggregation-induced quenching. Using the FRET reporting, three dissociation stages of FRET LNPs were observed: solvation, indicated by an increased emission intensity; swelling and partial dissolution, evidenced by changes in emission maxima and mean size; and complete dissociation, confirmed by emission solely from DiO and the absence of particles. Testing the nanoparticles in live cells (telomerase-immortalised human corneal epithelial cells, hTCEpi cells) revealed a direct link to the disappearance of the FRET signal with the dissociation of FRET NPs. The nanoparticles initially exhibited a strong extracellular FRET signal, which diminished after cellular internalisation. This suggests that the LNPs disintegrate after entering the cells. These findings establish FRET-based LNPs as a robust tool for real-time nanoparticle tracking, offering insights into their integrity and release mechanisms, with potential applications in advanced drug delivery and diagnostics.

Theranostic Lipid Nanoparticles for Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a common urological malignancy and represents a leading threat to healthcare. Recent years have seen a series of progresses in the early diagnosis and management of RCC. Theranostic lipid nanoparticles (LNPs) are increasingly becoming one of the focuses in this field, because of their suitability for tumor targeting and multimodal therapy. LNPs can be precisely fabricated with desirable chemical compositions and biomedical properties, which closely match the physiological characteristics and clinical needs of RCC. Herein, a comprehensive review of theranostic LNPs is presented, emphasizing the generic tool nature of LNPs in developing advanced micro-nano biomaterials. It begins with a brief overview of the compositions and formation mechanism of LNPs, followed with an introduction to kidney-targeting approaches, such as passive, active, and stimulus responsive targeting. With examples provided, a series of modification strategies for enhancing the tumor targeting and functionality of LNPs are discussed. Thereafter, research advances on applications of these LNPs for RCC including bioimaging, liquid biopsy, drug delivery, physical therapy, and gene therapy are summarized and discussed from an interdisciplinary perspective. The final part highlights the milestone achievements of translation medicine, current challenges as well as future development directions of LNPs for the diagnosis and treatment of RCC.

Advances with Lipid-Based Nanosystems for siRNA Delivery to Breast Cancers

Breast cancer is the most frequently diagnosed cancer among women. Breast cancer is also the key reason for worldwide cancer-related deaths among women. The application of small interfering RNA (siRNA)-based drugs to combat breast cancer requires effective gene silencing in tumor cells. To overcome the challenges of drug delivery to tumors, various nanosystems for siRNA delivery, including lipid-based nanoparticles that protect siRNA from degradation for delivery to cancer cells have been developed. These nanosystems have shown great potential for efficient and targeted siRNA delivery to breast cancer cells. Lipid-based nanosystems remain promising as siRNA drug delivery carriers for effective and safe cancer therapy including breast cancer. Lipid nanoparticles (LNPs) encapsulating siRNA enable efficient and specific silencing of oncogenes in breast tumors. This review discusses a variety of lipid-based nanosystems including cationic lipids, sterols, phospholipids, PEG-lipid conjugates, ionizable liposomes, exosomes for effective siRNA drug delivery to breast tumors, and the clinical translation of lipid-based siRNA nanosystems for solid tumors.