Synthetic antimicrobial and antibiofilm peptide (SAAP-148) commits significant antimicrobial activities against antimicrobial resistant (AMR) planktonic bacteria and biofilms. However, SAAP-148 is... Show moreSynthetic antimicrobial and antibiofilm peptide (SAAP-148) commits significant antimicrobial activities against antimicrobial resistant (AMR) planktonic bacteria and biofilms. However, SAAP-148 is limited by its low selectivity index, i.e., ratio between cytotoxicity and antimicrobial activity, as well as its bioavailability at infection sites. We hypothesized that formulation of SAAP-148 in PLGA nanoparticles (SAAP-148 NPs) improves the selectivity index due to the sustained local release of the peptide. The aim of this study was to investigate the physical and functional characteristics of SAAP-148 NPs and to compare the selectivity index of the formulated peptide with that of the peptide in solution. SAAP-148 NPs displayed favorable physiochemical properties [size = 94.1 +/- 23 nm, polydispersity index (PDI) = 0.08 +/- 0.1, surface charge = 1.65 +/- 0.1 mV, and encapsulation efficiency (EE) = 86.7 +/- 0.3%] and sustained release of peptide for up to 21 days in PBS at 37 degrees C. The antibacterial and cytotoxicity studies showed that the selectivity index for SAAP-148 NPs was drastically increased, by 10-fold, regarding AMR Staphylococcus aureus and 20-fold regarding AMR Acinetobacter baumannii after 4 h. Interestingly, the antibiofilm activity of SAAP-148 NPs against AMR S. aureus and A. baumannii gradually increased overtime, suggesting a dose-effect relationship based on the peptide's in vitro release profile. Using 3D human skin equivalents (HSEs), dual drug SAAP-148 NPs and the novel antibiotic halicin NPs provided a stronger antibacterial response against planktonic and cell-associated bacteria than SAAP-148 NPs but not halicin NPs after 24 h. Confocal laser scanning microscopy revealed the presence of SAAP-148 NPs on the top layers of the skin models in close proximity to AMR S. aureus at 24 h. Overall, SAAP-148 NPs present a promising yet challenging approach for further development as treatment against bacterial infections. Show less
Oosten, L. van; Altenburg, J.J.; Fougeroux, C.; Geertsema, C.; End, F. van den; Evers, W.A.C.; ... ; Pijlman, G.P. 2021
Vaccines pave the way out of the SARS-CoV-2 pandemic. Besides mRNA and adenoviral vector vaccines, effective protein-based vaccines are needed for immunization against current and emerging variants... Show moreVaccines pave the way out of the SARS-CoV-2 pandemic. Besides mRNA and adenoviral vector vaccines, effective protein-based vaccines are needed for immunization against current and emerging variants. We have developed a virus-like particle (VLP)-based vaccine using the baculovirus-insect cell expression system, a robust production platform known for its scalability, low cost, and safety. Baculoviruses were constructed encoding SARS-CoV-2 spike proteins: full-length S, stabilized secreted S, or the S1 domain. Since subunit S only partially protected mice from SARS-CoV-2 challenge, we produced S1 for conjugation to bacteriophage AP205 VLP nanoparticles using tag/catcher technology. The S1 yield in an insect-cell bioreactor was similar to 11 mg/liter, and authentic protein folding, efficient glycosylation, partial trimerization, and ACE2 receptor binding was confirmed. Prime-boost immunization of mice with 0.5 mu g S1-VLPs showed potent neutralizing antibody responses against Wuhan and UK/B.1.1.7 SARS-CoV-2 variants. This two-component nanoparticle vaccine can now be further developed to help alleviate the burden of COVID-19.IMPORTANCE Vaccination is essential to reduce disease severity and limit the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Protein-based vaccines are useful to vaccinate the world population and to boost immunity against emerging variants. Their safety profiles, production costs, and vaccine storage temperatures are advantageous compared to mRNA and adenovirus vector vaccines. Here, we use the versatile and scalable baculovirus expression vector system to generate a two-component nanoparticle vaccine to induce potent neutralizing antibody responses against SARS-CoV-2 variants. These nanoparticle vaccines can be quickly adapted as boosters by simply updating the antigen component. Show less
Zhou, X.Q.; Mytiliniou, M.; Hilgendorf, J.; Zeng, Y.; Papadopoulou, P.; Shao, Y.; ... ; Bonnet, S. 2021
Many drug delivery systems end up in the lysosome because they are built from covalent or kinetically inert supramolecular bonds. To reach other organelles, nanoparticles hence need to either be... Show moreMany drug delivery systems end up in the lysosome because they are built from covalent or kinetically inert supramolecular bonds. To reach other organelles, nanoparticles hence need to either be made from a kinetically labile interaction that allows re-assembly of the nanoparticles inside the cell following endocytic uptake, or, be taken up by a mechanism that short-circuits the classical endocytosis pathway. In this work, the intracellular fate of nanorods that self-assemble via the Pt horizontal ellipsis Pt interaction of cyclometalated platinum(II) compounds, is studied. These deep-red emissive nanostructures (638 nm excitation, approximate to 700 nm emission) are stabilized by proteins in cell medium. Once in contact with cancer cells, they cross the cell membrane via dynamin- and clathrin-dependent endocytosis. However, time-dependent confocal colocalization and cellular electron microscopy demonstrate that they directly move to mitochondria without passing by the lysosomes. Altogether, this study suggests that Pt horizontal ellipsis Pt interaction is strong enough to generate emissive, aggregated nanoparticles inside cells, but labile enough to allow these nanostructures to reach the mitochondria without being trapped in the lysosomes. These findings open new venues to the development of bioimaging nanoplatforms based on the Pt horizontal ellipsis Pt interaction. Show less
Sier, V.Q.; Vries, M.R. de; Vorst, J.R. van der; Vahrmeijer, A.L.; Kooten, C. van; Cruz, L.J.; ... ; Muthana, M. 2021
Surgeons rely almost completely on their own vision and palpation to recognize affected tissues during surgery. Consequently, they are often unable to distinguish between different cells and tissue... Show moreSurgeons rely almost completely on their own vision and palpation to recognize affected tissues during surgery. Consequently, they are often unable to distinguish between different cells and tissue types. This makes accurate and complete resection cumbersome. Targeted image-guided surgery (IGS) provides a solution by enabling real-time tissue recognition. Most current targeting agents (tracers) consist of antibodies or peptides equipped with a radiolabel for Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT), magnetic resonance imaging (MRI) labels, or a near-infrared fluorescent (NIRF) dye. These tracers are preoperatively administered to patients, home in on targeted cells or tissues, and are visualized in the operating room via dedicated imaging systems. Instead of using these 'passive' tracers, there are other, more 'active' approaches of probe delivery conceivable by using living cells (macrophages/monocytes, neutrophils, T cells, mesenchymal stromal cells), cell(-derived) fragments (platelets, extracellular vesicles (exosomes)), and microorganisms (bacteria, viruses) or, alternatively, 'humanized' nanoparticles. Compared with current tracers, these active contrast agents might be more efficient for the specific targeting of tumors or other pathological tissues (e.g., atherosclerotic plaques). This review provides an overview of the arsenal of possibilities applicable for the concept of cell-based tracers for IGS. Show less
This review establishes an inventory of existing toxicity data on nanoparticles (NPs) with thepurpose of developing (Quantitative) Structure–Activity Relationships for NPs (nano-[Q]SARs), and also... Show moreThis review establishes an inventory of existing toxicity data on nanoparticles (NPs) with thepurpose of developing (Quantitative) Structure–Activity Relationships for NPs (nano-[Q]SARs), and also ofmaximising the use of scientific sources for NP risk assessment. From a data search carried out on 27February 2014, a total of 910 publications were retrieved from the Web of Science™ Core Collection, anda database comprising 886 records of toxicity endpoints, based on these publications, was built. The testorganisms mainly comprised bacteria, algae, yeast, protozoa, nematoda, crustacea and fish. The NPs consistedmostly of metals, metal oxides, nanocomposites and quantum dots. The data were analysed further,in order to: a) categorise each toxicity endpoint and the biological effects triggered by the NPs; b) surveythe characterisation of the NPs used; and c) assess whether the data were suitable for nano-(Q)SAR development.Despite the efforts of numerous scientific programmes on nanomaterial safety and design, ourstudy concluded that lack of data consistency prevents the use of experimental data in developing and validatingnano-(Q)SARs. Finally, an outlook on the future of nano-(Q)SAR development is provided. Show less
