Single Pulse Nanosecond Laser-Stimulated Targeted Delivery of Anti-Cancer Drugs from Hybrid Lipid Nanoparticles Containing 5 nm Gold Nanoparticles

Emerging ultrafast technologies in biotechnology

This review highlights the transformative applications of ultrafast technologies in biotechnology, focusing on their ability to provide real-time visualization and precise manipulation of biomolecular processes. Femtosecond lasers have enhanced precision in gene editing, minimizing off-target effects, while ultrafast spectroscopy has advanced understanding of protein folding pathways, enzymatic activity, and energy transfer mechanisms. Notable findings include the identification of protein folding intermediates linked to misfolding diseases, improved insights into enzymatic catalysis through hydration studies, and the development of real-time monitoring systems for CRISPR gene editing. Imaging innovations such as pump-probe microscopy and Coherent Anti-Stokes Raman Scattering (CARS) enable high-resolution observation of cellular dynamics, intracellular signaling, and neural activity. Furthermore, attosecond spectroscopy has provided unprecedented insights into ultrafast electron dynamics and charge migration. Integrating ultrafast technologies with AI and nanotechnology has accelerated advances in diagnostics, personalized medicine, and synthetic biology, driving breakthroughs in drug discovery, targeted therapeutics, and regenerative medicine. Despite challenges such as photodamage, integration with complex biological systems, and ethical considerations, ongoing advancements in ultrafast technologies are set to revolutionize biotechnology. These innovations hold immense potential for addressing critical challenges in healthcare and life sciences, enabling transformative progress in understanding and treating complex diseases.

Cathepsin B-induced cascade DNA-AuNP nanomachine for activated tumor theranostics

Since targeted and efficient accumulation of nanoparticles into tumors is essential for accurate cancer theranostics, spatiotemporally controlling the aggregation of small nanoparticles (such as gold nanoparticles, AuNPs) in the tumor microenvironment holds significant promise for improving the diagnostic and therapeutic efficiency against tumors. Here, we introduce a cascade DNA-AuNP nanomachine (CNM) that can in situ magnify the protease-catalyzed peptide cleavage via DNA amplification machinery for cathepsin B (Cat B) activity imaging and Cat B-responsive photothermal therapy of tumors. The CNM is composed of a nanomediator formed by tethering a mediator DNA/peptide complex on AuNPs (DpAuNP) and a nanoeffector consisted of AuNPs and DNA modules (DNA-AuNP). In the cascade, Cat B-mediated peptide cleavage of mediator DNA/peptide complex on DpAuNPs initiates both the detachment of fluorescent DNA reporter from DNA-AuNPs for Cat B imaging and the aggregation of AuNPs for tumor photothermal therapy via toehold-mediated stand displacement (TMSD) reaction. Our results demonstrate that the CNM not only offers superior sensitivity and specificity for Cat B imaging, but also facilitates the activated aggregation of AuNPs for enhanced photothermal therapy of tumors. This CNM represents a Cat B-specific sense-and-treat paradigm for cancer theranostics.

Radiosensitizing capacity of fenofibrate in glioblastoma cells depends on lipid metabolism

Despite advances in multimodal therapy approaches such as resection, chemotherapy and radiotherapy, the overall survival of patients with grade 4 glioblastoma (GBM) remains extremely poor (average survival time <2 years). Altered lipid metabolism, which increases fatty acid synthesis and thereby contributes to radioresistance in GBM, is a hallmark of cancer. Therefore, we explored the radiosensitizing effect of the clinically approved, lipid-lowering drug fenofibrate (FF) in different GBM cell lines (U87, LN18). Interestingly, FF (50 μM) significantly radiosensitizes U87 cells by inducing DNA double-strand breaks through oxidative stress and impairing mitochondrial membrane integrity, but radioprotects LN18 cells by reducing the production of reactive oxygen species (ROS) and stabilizing the mitochondrial membrane potential. A comparative protein and lipid analysis revealed striking differences in the two GBM cell lines: LN18 cells exhibited a significantly higher membrane expression density of the fatty acid (FA) cluster protein transporter CD36 than U87 cells, a higher expression of glycerol-3-phosphate acyltransferase 4 (GPAT4) which supports the production of large lipid droplets (LDs), and a lower expression of diacylglycerol O-acyltransferase 1 (DGAT1) which regulates the formation of small LDs. Consequently, large LDs are predominantly found in LN18 cells, whereas small LDs are found in U87 cells. After a combined treatment of FF and irradiation, the number of large LDs significantly increased in radioresistant LN18 cells, whereas the number of small LDs decreased in radiosensitive U87 cells. The radioprotective effect of FF in LN18 cells could be associated with the presence of large LDs, which act as a sink for the lipophilic drug FF. To prevent uptake of FF by large LDs and to ameliorate its function as a radiosensitizer, FF was encapsulated in biomimetic cell membrane extracellular lipid vesicles (CmEVs) which alter the intracellular trafficking of the drug. In contrast to the free drug, CmEV-encapsulated FF was predominantly enriched in the lysosomal compartment, causing necrosis by impairing lysosomal membrane integrity. Since the stability of plasma and lysosomal membranes is maintained by the presence of the stress-inducible heat shock protein 70 (Hsp70) which has a strong affinity to tumor-specific glycosphingolipids, necrosis occurs predominantly in LN18 cells having a lower membrane Hsp70 expression density than U87 cells. In summary, our findings indicate that the lipid metabolism of tumor cells can affect the radiosensitizing capacity of FF when encountered either as a free drug or as a drug loaded in biomimetic lipid vesicles.

In Situ Labeling of the Aqueous Compartment of Extracellular Vesicles with Luminescent Gold Nanoclusters

Extracellular vesicles (EVs) are well-known membrane-limited particles secreted by both healthy and cancerous cells. They are considered as biomarkers for early cancer diagnosis and are involved in many pathologies and physiological pathways. They could serve as diagnostic tools in liquid biopsies, as therapeutics in regenerative medicine, or as drug delivery vehicles. Our aim is here to encapsulate luminescent nanoprobes in the aqueous compartment of human EVs extracted from reproductive fluids. The analysis and labeling of the EVs content with easily detectable luminescent nanoparticles could enable a powerful tool for early diagnosis of specific diseases and also for the design of new therapeutics. In this view, gold nanoclusters (AuNCs) appear as an attractive alternative as nontoxic fluorophore probes because of their luminescence properties, large window of fluorescence lifetimes (1 ns-1 μs), ultrasmall size (<2 nm), good biocompatibility, and specific ability as X-ray photosensitizers. Here, we investigated an attractive method that uses fusogenic liposomes to deliver gold nanoclusters into EVs. This approach guarantees the preservation of the EVs membrane without any breakage, thus maintaining compartmental integrity. Different lipid compositions of liposomes preloaded with AuNCs were selected to interact electrostatically with human EVs and compared in terms of fusion efficiency. The mixture of liposomes and EVs results in membrane mixing as demonstrated by FRET experiments and fusion revealed by flux cytometry and cryo-TEM. The resulting fused EVs exhibit typical fluorescence of the AuNCs together with an increased size in agreement with fusion. Moreover, the fusion events in mixtures of EVs and AuNCs preloaded liposomes were analyzed by using cryo-electron microscopy. Finally, the ratio of released AuNCs during the fusion between the fusogenic liposomes and the EVs was estimated to be less than 20 mol % by Au titration using ICP spectroscopy.