Publications

ConspectusDelivering biological effector molecules in cultured cells is of fundamental importance to any study or application in which the modulation of gene expression is required. Examples range from generating engineered cell lines for studying gene function to the engineering of cells for cell-based therapies such as CAR-T cells and gene-corrected stem cells for regenerative medicine. It remains a great challenge, however, to deliver biological effector molecules across the cell membrane with minimal adverse effects on cell viability and functionality. While viral vectors have been frequently used to introduce foreign nucleic acids into cells, their use is associated with safety concerns such as immunogenicity, high manufacturing cost, and limited cargo capacity.For photoporation, depending on the laser energy, membrane permeabilization happens either by local heating or by laser-induced water vapor nanobubbles (VNB). In our first study on this topic, we demonstrated that the physical force exerted by suddenly formed VNB leads to more efficient intracellular delivery as compared to mere heating. Next, we explored the use of different photothermal nanomaterials, finding that graphene quantum dots display enhanced thermal stability compared to the more traditionally used gold nanoparticles, hence providing the possibility to increase the delivery efficiency by repeated laser activation. To enable its use for the production of engineered therapeutic cells, it would be better if contact with cells with nondegradable nanoparticles is avoided as it poses toxicity and regulatory concerns. Therefore, we recently demonstrated that photoporation can be performed with biodegradable polydopamine nanoparticles as well. Alternatively, we demonstrated that nanoparticle contact can be avoided by embedding the photothermal nanoparticles in a substrate made from biocompatible electrospun nanofibers. With this variety of photoporation approaches, over the years we demonstrated the successful delivery of a broad variety of biologics (mRNA, siRNA, Cas9 ribonucleoproteins, nanobodies, etc.) in many different cell types, including hard-to-transfect cells such as T cells, embryonic stem cells, neurons, and macrophages.In this Account, we will first start with a brief introduction of the general concept and a historical development of photoporation. In the next two sections, we will extensively discuss the various types of photothermal nanomaterials which have been used for photoporation. We discriminate two types of photothermal nanomaterials: single nanostructures and composite nanostructures. The first one includes examples such as gold nanoparticles, graphene quantum dots, and polydopamine nanoparticles. The second type includes polymeric films and nanofibers containing photothermal nanoparticles as well as composite nanoscale biolistic nanostructures. A thorough discussion will be given for each type of photothermal nanomaterial, from its synthesis and characterization to its application in photoporation, with its advantages and disadvantages. In the final section, we will provide an overall discussion and elaborate on future perspectives.

JTD Keywords: cells, delivery, macromolecules, nanoparticles, Gold, Graphite, In-vitro, Metal nanoparticles, Nanostructures, Quantum dots

Quantum dots (QDs) are semiconductor nanoparticles with unique optical and electronic properties, whose interest as potential nano-theranostic platforms for imaging and sensing is increasing. The design and use of QDs requires the understanding of cell-nanoparticle interactions at a microscopic and nanoscale level. Model systems such as supported lipid bilayers (SLBs) are useful, less complex platforms mimicking physico-chemical properties of cell membranes. In this work, we investigated the effect of topographical homogeneity of SLBs bearing different surface charge in the adsorption of hydrophilic QDs. Using quartz-crystal microbalance, a label-free surface sensitive technique, we show significant differences in the interactions of QDs onto homogeneous and inhomogeneous SLBs formed following different strategies. Within short time scales, QDs adsorb onto topographically homogeneous, defect-free SLBs is driven by electrostatic interactions, leading to no layer disruption. After prolonged QD exposure, the nanomechanical stability of the SLB decreases suggesting nanoparticle insertion. In the case of inhomogeneous, defect containing layers, QDs target preferentially membrane defects, driven by a subtle interplay of electrostatic and entropic effects, inducing local vesicle rupture and QD insertion at membrane edges. © 2021

JTD Keywords: adsorption, atomic force microscopy, bilayer formation, gold nanoparticles, hydrophilic quantum dots, lipid membrane defects, model, nanomechanics, quartz crystal microbalance with dissipation, size, supported lipid bilayers, surfaces, Atomic force microscopy, Atomic-force-microscopy, Cytology, Defect-free, Electronic properties, Electrostatics, Hydrophilic quantum dot, Hydrophilic quantum dots, Hydrophilicity, Hydrophilics, Lipid bilayers, Lipid membrane defect, Lipid membrane defects, Lipid membranes, Lipids, Nanocrystals, Nanomechanics, Optical and electronic properties, Quartz, Quartz crystal microbalance with dissipation, Quartz crystal microbalances, Quartz-crystal microbalance, Semiconductor nanoparticles, Semiconductor quantum dots, Supported lipid bilayers

Nanomedicine involves the use of nanotechnology for clinical applications and holds promise to improve treatments. Recent developments offer new hope for cancer detection, prevention and treatment; however, being a heterogenous disorder, cancer calls for a more targeted treatment approach. Personalized Medicine (PM) aims to revolutionize cancer therapy by matching the most effective treatment to individual patients. Nanotheranostics comprise a combination of therapy and diagnostic imaging incorporated in a nanosystem and are developed to fulfill the promise of PM by helping in the selection of treatments, the objective monitoring of response and the planning of follow-up therapy. Although well-established imaging techniques, such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT), are primarily used in the development of theranostics, Optical Imaging (OI) offers some advantages, such as high sensitivity, spatial and temporal resolution and less invasiveness. Additionally, it allows for multiplexing, using multi-color imaging and DNA barcoding, which further aids in the development of personalized treatments. Recent advances have also given rise to techniques permitting better penetration, opening new doors for OI-guided nanotheranostics. In this review, we describe in detail these recent advances that may be used to design and develop efficient and specific nanotheranostics for personalized cancer drug delivery. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: 5-aminolevulinic acid, cancer, contrast agents, in-vivo, malignant gliomas, multifunctional nanoparticles, nanomedicine, optical imaging, ovarian-cancer, personalized medicine, quantum dots, silica nanoparticles, targeted probes, theranostics, Cancer, Nanomedicine, Optical imaging, Personalized medicine, Superparamagnetic iron-oxide, Theranostics

Nanotechnological devices for therapeutic applications are massively addressed to diseases prevalent in the developed world, particularly cancer, because of the wrong assumption (for both ethical and technical reasons) that nanomedicines are too expensive and thus they can not be applied to diseases of poverty. Here we have applied quantum dots to study at the cellular level the delivery of the contents of liposomes to erythrocytes infected by the malaria parasite Plasmodium falciparum, and to macrophages infected by the leishmaniasis causative agent Leishmania infantum. A number of works have reported on the encapsulation in liposomes of drugs against both diseases as a strategy to increase therapeutic efficacy and decrease unspecific toxicity. Liposome-carried drugs end up inside Plasmodium-infected red blood cells (pRBCs) and in the phagolysosome system of Leishmania-infected macrophages but some knowledge gaps still obscure subcellular events related to these processes. As a proof of concept, we have used confocal fluorescence microscopy to follow the fate in pRBCs and infected macrophages of quantum dots encapsulated in liposomes, and of lysosomes, leishmaniasis and malaria parasites, nuclei, and phagosomes. Our data indicate that liposomes merge their lipid bilayers with pRBC plasma membranes but are engulfed by macrophages, where they fuse with lysosomes. Lysosomes have not been observed to join with phagosomes harboring single Leishmania parasites, whereas in phagosomes where the parasite has divided there is lysosome-specific fluorescence with a concomitant disappearance of lysosomes from the cytosol. In later stages, all the lysosome-specific label is found inside phagosomes whereas the phagosomal marker cadaverine strongly stains the macrophage nucleus, suggesting that Leishmania infection induces in its later stages nuclear degeneration and, possibly, apoptosis of the host cell. These results indicate that induction of macrophage apoptosis should be explored as a possible strategy used by Leishmania to prepare its egress.

JTD Keywords: Leishmania infantum, Leishmaniasis Liposomes, Malaria, Nanomedicine, Nanotechnology, Plasmodium falciparum, Quantum dots

Nanotechnological devices for therapeutic applications are massively addressed to diseases prevalent in the developed world, particularly cancer, because of the wrong assumption (for both ethical and technical reasons) that nanomedicines are too expensive and thus they can not be applied to diseases of poverty. Here we have applied quantum dots to study at the cellular level the delivery of the contents of immunoliposomes to erythrocytes infected by the malaria parasite Plasmodium falciparum, and to macrophages infected by the leishmaniasis causative agent Leishmania infantum. A number of works have reported on the encapsulation in liposomes of drugs against both diseases as a strategy to increase therapeutic efficacy and decrease unspecific toxicity. Liposome-carried drugs end up inside Plasmodium-infected red blood cells (pRBCs) and in the phagolysosome system of Leishmania-infected macrophages but some knowledge gaps still obscure subcellular events related to these processes. As a proof of concept, we have used confocal fluorescence microscopy to follow the fate in pRBCs and L. infantum-infected macrophages of quantum dots encapsulated in liposomes, and of lysosomes, Leishmania and Plasmodium parasites, nuclei, and phagosomes. Our data indicate that liposomes merge their lipid bilayers with pRBC plasma membranes but are engulfed by macrophages, where they fuse with lysosomes. Lysosomes have not been observed to join with phagosomes harboring single L. infantum parasites, whereas in phagosomes where the parasite has divided there is lysosome-specific fluorescence with a concomitant disappearance of lysosomes from the cytosol. In later stages, all the lysosome-specific label is found inside phagosomes whereas the phagosomal marker cadaverine strongly stains the macrophage nucleus, suggesting that L. infantum infection induces in its later stages nuclear degeneration and possibly, apoptosis of the host cell. These results indicate that induction of macrophage apoptosis should be explored as a possible strategy used by L. infantum to prepare its egress.

JTD Keywords: Leishmania infantum, Leishmaniasis, Liposomes, Malaria, Nanomedicine, Nanotechnology, Plasmodium falciparum, Quantum dots