Interactions at the cell membrane and pathways of internalization of nano-sized materials for nanomedicine

• Valentina Francia,
• Daphne Montizaan and
• Anna Salvati

Beilstein J. Nanotechnol. 2020, 11, 338–353, doi:10.3762/bjnano.11.25

• receptors, and the subsequent mechanisms cells use to internalize them. The factors affecting these initial events are discussed. Then, we briefly describe the different pathways of endocytosis in cells and illustrate with some examples the challenges in understanding how nanomaterial properties, such as

• . Keywords: cell receptors; drug targeting; endocytosis; nanoparticle corona; nanoparticle uptake; Introduction Nano-sized materials are widely studied in nanomedicine for their potential use as drug carriers, in imaging, and for diagnostic purposes [1][2][3]. Because of their size, they can interact with

• of cellular internalization, i.e., endocytosis. Then, examples of works trying to understand how nanomaterial properties affect the mechanisms of uptake by cells are presented to illustrate the complexity of outcomes observed and the difficulties in drawing conclusions. 2.1 Pathways of endocytosis in

Rational design of block copolymer self-assemblies in photodynamic therapy

• Maxime Demazeau,
• Laure Gibot,
• Anne-Françoise Mingotaud,
• Patricia Vicendo,
• Clément Roux and
• Barbara Lonetti

Beilstein J. Nanotechnol. 2020, 11, 180–212, doi:10.3762/bjnano.11.15

• carcinoma, ovarian, kidney, and pancreatic cancer). Chang et al. have explored the potential of PLA-PEG-AntiEGFR self-assemblies loaded with chlorin-e6 as a photosensitizer and found that this construct led to the increased internalization of the micelles through receptor-mediated endocytosis, which in turn

• efficiency using elongated vectors compared to spherical ones [137][138][139]. Simulations [139][140][141] showed that from a thermodynamic standpoint it is always more favorable to encapsulate spherocylindrical particles instead of spheres with the same radius and that endocytosis of spherocylinders occurs

Internalization mechanisms of cell-penetrating peptides

• Ivana Ruseska and
• Andreas Zimmer

Beilstein J. Nanotechnol. 2020, 11, 101–123, doi:10.3762/bjnano.11.10

• the cell interior. Nevertheless, the mechanism they use to enter cells still remains an unsolved piece of the puzzle. Endocytosis and direct penetration have been suggested as the two major mechanisms used for internalization, however, it is not all black and white in the nanoworld. Studies have shown

• influence the cellular uptake mechanism. Keywords: cell-penetrating peptides; direct translocation; drug delivery; endocytosis; internalization; Introduction The cell membrane is a semipermeable barrier, serving as a protective layer for the cells. It is an essential organelle for cell survival and

• , just a few out of many, guide the internalization paths of CPPs to two major routes: endocytosis (active or energy-dependent uptake) and membrane translocation (direct/passive or energy-independent uptake). Overall, the type of uptake which will be selected mainly depends on the physicochemical

Bombesin receptor-targeted liposomes for enhanced delivery to lung cancer cells

• Mohammad J. Akbar,
• Pâmela C. Lukasewicz Ferreira,
• Melania Giorgetti,
• Leanne Stokes and
• Christopher J. Morris

Beilstein J. Nanotechnol. 2019, 10, 2553–2562, doi:10.3762/bjnano.10.246

• -bound through GRPR binding cf. non-targeted liposomes, which exchange rapidly between the free and cell surface-bound state, would indirectly increase the relative intracellular accumulation. Access to the intracellular compartment would be achieved by constitutive plasma membrane endocytosis (e.g

• relative cellular accumulation (data not shown). To overcome this, the density of targeting lipid was increased to 3 mol %. To examine for active internalisation and intracellular accumulation of liposomes at the endocytosis permissive temperature of 37 °C, we subtracted the median fluorescence intensity

Small protein sequences can induce cellular uptake of complex nanohybrids

• Jan-Philip Merkl,
• Malak Safi,
• Christian Schmidtke,
• Fadi Aldeek,
• Johannes Ostermann,
• Tatiana Domitrovic,
• Sebastian Gärtner,
• John E. Johnson,
• Horst Weller and
• Hedi Mattoussi

Beilstein J. Nanotechnol. 2019, 10, 2477–2482, doi:10.3762/bjnano.10.238

• the processes involved in the intracellular uptake and ensuing distribution of various nanomaterials [9]. Several studies have consistently found that NPs are very often taken up by endocytosis, and once inside the cells they remain trapped within endosomal compartments [10][12]. A few other studies

• reported that a sizable fraction of the delivered nanoparticles can end up in the cytoplasm, by either circumventing endocytosis through the use of virus-derived peptide sequences, or non-disruptively penetrating the cellular membranes [13]. Escape from endosomal vesicles of once endocytosed nanoparticles

• may not be driven by endocytosis [22]. Nonetheless, the distribution of the QD fluorescence is still different from that expected for a pure cytosolic delivery, where a more homogeneous distribution of the signal would be expected [33]. Whether these findings are due to the cellular response on the NP

Synthesis and potent cytotoxic activity of a novel diosgenin derivative and its phytosomes against lung cancer cells

• Liang Xu,
• Dekang Xu,
• Ziying Li,
• Yu Gao and
• Haijun Chen

Beilstein J. Nanotechnol. 2019, 10, 1933–1942, doi:10.3762/bjnano.10.189

• of apoptosis, suggesting that the actions of P2 on induction of cell apoptosis could be altered after loading in phytosomes. One reason might be the changed drug uptake pathway. The free drugs were taken up by passive transport, while the phytosomes were taken up through endocytosis [39]. Besides

Engineered superparamagnetic iron oxide nanoparticles (SPIONs) for dual-modality imaging of intracranial glioblastoma via EGFRvIII targeting

• Xianping Liu,
• Chengjuan Du,
• Haichun Li,
• Ting Jiang,
• Zimiao Luo,
• Zhiqing Pang,
• Daoying Geng and
• Jun Zhang

Beilstein J. Nanotechnol. 2019, 10, 1860–1872, doi:10.3762/bjnano.10.181

• enhanced accumulation of PNPs in EGFRvIII-positive tumors. Further TEM imaging demonstrated that plenty of the PNP nanoprobes accumulated in U87-EGFRvIII cells, suggesting the increased endocytosis of PNPs in U87-EGFRvIII cells (Figure 8b). Primary safety evaluation of PNPs The cytotoxicity of nanoprobes

Targeting strategies for improving the efficacy of nanomedicine in oncology

• Gonzalo Villaverde and
• Alejandro Baeza

Beilstein J. Nanotechnol. 2019, 10, 168–181, doi:10.3762/bjnano.10.16

• strategy is the so-called “cellular or secondary targeting”, because it is generally based on a ligand–receptor-mediated endocytosis, triggered by the strong interaction of the targeting group with the membrane receptor of the tumoral cell. It improves the selectivity of the treatment achieving a drastic

• the action of a cell surface-associated protease exposing the RGD, which then binds to neuropilin-1 triggering the particle endocytosis. Another cell-penetrating peptide (or CPP, which is the usual name of the peptides used for targeting purposes in nanomedicine) closely related to RGD is the

• is endocytosis [51]. Usually, the nanocarriers enter into the cells into endosomes, which evolve into lysosomes, which can lead to the degradation of the transported cargo, especially in the case of sensitive agents such as genes or siRNA. Therefore, it is necessary to design mechanisms to induce the

Cytotoxicity of doxorubicin-conjugated poly[N-(2-hydroxypropyl)methacrylamide]-modified γ-Fe₂O₃ nanoparticles towards human tumor cells

• Zdeněk Plichta,
• Yulia Kozak,
• Rostyslav Panchuk,
• Viktoria Sokolova,
• Matthias Epple,
• Lesya Kobylinska,
• Pavla Jendelová and
• Daniel Horák

Beilstein J. Nanotechnol. 2018, 9, 2533–2545, doi:10.3762/bjnano.9.236

• their enhanced accumulation inside the cells. The particles are able to penetrate cells by the selected type of endocytosis mechanism: phagocytosis, pinocytosis, or receptor mediated endocytosis [25]. In order to check this hypothesis, cellular uptake of γ-Fe2O3@P(HPMA-MMAA)-Dox nanoparticles was

Nanoparticle delivery to metastatic breast cancer cells by nanoengineered mesenchymal stem cells

• Liga Saulite,
• Karlis Pleiko,
• Ineta Popena,
• Dominyka Dapkute,
• Ricardas Rotomskis and
• Una Riekstina

Beilstein J. Nanotechnol. 2018, 9, 321–332, doi:10.3762/bjnano.9.32

• ) compared with 3D culture (Figure 4B). To the contrary, MDA-MB-231 internalised 6-fold more QDs in 3D culture compared with 2D (Figure 4B). Such discrepancy in uptake efficacy might be associated with different endocytosis pathways. MCF7 cells internalised QDs through phagocytosis and clathrin/caveolae

• -dependent endocytosis, whereas the clathrin/caveolae-dependent pathway dominated in MDA-MB-231 cells in monocultures (Supporting Information File 1, Figure S2). Cell viability in 3D culture Cells in a 3D culture formed floating and dense spheroids. Therefore, we sought to analyse the effect of the 3D

• facilitating the uptake of MSC-excreted QDs by cancer cells. Our data demonstrate that phagocytosis and clathrin/caveolae-dependent endocytosis are the major QD uptake pathways in MCF7 cells, whereas the clathrin/caveolae-dependent pathway dominated in MDA-MB-231 cells in monocultures (see Supporting

Involvement of two uptake mechanisms of gold and iron oxide nanoparticles in a co-exposure scenario using mouse macrophages

• Dimitri Vanhecke,
• Dagmar A. Kuhn,
• Dorleta Jimenez de Aberasturi,
• Sandor Balog,
• Ana Milosevic,
• Dominic Urban,
• Diana Peckys,
• Niels de Jonge,
• Wolfgang J. Parak,
• Alke Petri-Fink and
• Barbara Rothen-Rutishauser

Beilstein J. Nanotechnol. 2017, 8, 2396–2409, doi:10.3762/bjnano.8.239

• negative, must be considered for nanotechnology and nanomedicine in particular to develop to its full potential. Keywords: co-exposure; endocytosis; live cell imaging; nanoparticles; quantitative microscopy; Introduction Over the past two decades, improvements in nanomaterial research were followed by a

• , which can be subdivided into macro- and microscale processes [8]. The first, phagocytosis, involves the ingestion of large particles: NPs or agglomerates typically larger than 0.25 μm in diameter. The second, pinocytosis, includes micro- and macropinocytosis, clathrin-, and caveolin-mediated endocytosis

• , and clathrin- and caveolin-independent endocytosis, involving the ingestion of fluid, molecules, and NPs via small vesicles (<0.15 µm in diameter) [9]. Although NPs have been shown to be taken up by the cells mainly by pinocytotis [9], many factors have been shown to influence the interaction with

Uptake and intracellular accumulation of diamond nanoparticles – a metabolic and cytotoxic study

• Antonín Brož,
• Lucie Bačáková,
• Pavla Štenclová,
• Alexander Kromka and
• Štěpán Potocký

Beilstein J. Nanotechnol. 2017, 8, 1649–1657, doi:10.3762/bjnano.8.165

• in cultures exposed and unexposed to photoluminescent nanodiamonds. This positive effect can be attributed to the fact that the mechanism of the ND uptake was clathrin-mediated endocytosis, that is, a physiological cellular mechanism for internalization of various bioactive substances from the

Nano-engineered skin mesenchymal stem cells: potential vehicles for tumour-targeted quantum-dot delivery

• Liga Saulite,
• Dominyka Dapkute,
• Karlis Pleiko,
• Ineta Popena,
• Simona Steponkiene,
• Ricardas Rotomskis and
• Una Riekstina

Beilstein J. Nanotechnol. 2017, 8, 1218–1230, doi:10.3762/bjnano.8.123

• examined via fluorescence imaging using endocytosis inhibitors for the micropinocytosis, phagocytosis, lipid-raft, clathrin- and caveolin-dependent endocytosis pathways. These data showed that QDs were efficiently accumulated in the cytoplasm of MSCs after incubation for 6 h. The main uptake route of QDs

• in skin MSCs was clathrin-mediated endocytosis. QDs were mainly localized in early endosomes after 6 h as well as in late endosomes and lysosomes after 24 h. QDs in concentrations ranging from 0.5 to 64 nM had no effect on cell viability and proliferation. The expression of MSC markers, CD73 and CD90

• suggest that QD-labelled MSCs could be used for targeted drug delivery studies. Keywords: endocytosis; mesenchymal stem cells; quantum dots; stem cell differentiation; Introduction Despite remarkable advances in targeted therapies of various human malignancies, cancer is one of the leading causes of

Uptake of the proteins HTRA1 and HTRA2 by cells mediated by calcium phosphate nanoparticles

• Olga Rotan,
• Katharina N. Severin,
• Simon Pöpsel,
• Alexander Peetsch,
• Melisa Merdanovic,
• Michael Ehrmann and
• Matthias Epple

Beilstein J. Nanotechnol. 2017, 8, 381–393, doi:10.3762/bjnano.8.40

• flow cytometry. All proteins were readily transported into the cells by cationic calcium phosphate nanoparticles. Notably, only HTRA1 was able to penetrate the cell membrane of MG-63 cells in dissolved form. However, the application of endocytosis inhibitors revealed that the uptake pathway was

• different for dissolved HTRA1 and HTRA1-loaded nanoparticles. Keywords: calcium phosphate; endocytosis; nanoparticles; proteins; Introduction Many receptors for drugs or proteins are located inside cells [1][2]. However, because many biomolecules are not able to penetrate the cell membrane on their own, a

• suitable carrier is required [3][4]. Nanoparticles are readily taken up by cells via endocytosis and are easily able to deliver their cargo into cells across the cell membrane [5][6][7]. Calcium phosphate nanoparticles have demonstrated to be very efficient to transport (bio)molecules into cells [8][9

Viability and proliferation of endothelial cells upon exposure to GaN nanoparticles

• Tudor Braniste,
• Ion Tiginyanu,
• Tibor Horvath,
• Simion Raevschi,
• Serghei Cebotari,
• Marco Lux,
• Axel Haverich and
• Andres Hilfiker

Beilstein J. Nanotechnol. 2016, 7, 1330–1337, doi:10.3762/bjnano.7.124

• susceptible for them. In contrast to this situation, the cells take up all the GaN nanoparticles floating in the medium, thus burning energy via the endocytosis process and slowing down the proliferation activity. Conclusion We found that the interaction of porcine endothelial cells with GaN nanoparticles

On the pathway of cellular uptake: new insight into the interaction between the cell membrane and very small nanoparticles

• Claudia Messerschmidt,
• Daniel Hofmann,
• Anja Kroeger,
• Katharina Landfester,
• Volker Mailänder and
• Ingo Lieberwirth

Beilstein J. Nanotechnol. 2016, 7, 1296–1311, doi:10.3762/bjnano.7.121

• : ATP depletion; calcium crystallization; cytotoxicity; endocytosis; HeLa cells; LDH; mesenchymal stem cells; morphology; necrosis; particle size; silica nanoparticles; TEM; Introduction Silicon dioxide nanoparticles (SiNPs) are used in a wide range of commercially available products to improve product

• see a size dependency of NP endocytosis (Figure 4, Figure 10, Figure 11). The endocytic route for the larger of our examined NPs (SiNP-22 and SiNP-12) can be described as following: First the NPs are taken up as individuals or in small groups and are found in the cytosol with tightly wrapping membrane

• additional silica layer is likely to change the viscoelastic properties of the cell membrane yielding an increased maximum bending radius. Nevertheless, the cell manages to perform the pinch-off which is indicative for an active endocytic process. Moreover, when suppressing any active endocytosis by cooling

Improved biocompatibility and efficient labeling of neural stem cells with poly(L-lysine)-coated maghemite nanoparticles

• Igor M. Pongrac,
• Marina Dobrivojević,
• Lada Brkić Ahmed,
• Michal Babič,
• Miroslav Šlouf,
• Daniel Horák and
• Srećko Gajović

Beilstein J. Nanotechnol. 2016, 7, 926–936, doi:10.3762/bjnano.7.84

• ]. Endocytosis as a process of internalization of foreign materials can be divided into two major groups, phagocytosis for larger particles and pinocytosis for nanoparticles. Pinocytosis can be further subdivided depending on the size of particles into clathrin-mediated, caveolae, and macropinocytosis [25]. To

• -dependent process macropinocytosis cytochalasine D, inhibitor of microtubule function involved in intracellular vesicle trafficking nocodazole, inhibitor of the clathrin-mediated endocytosis phenylarsine oxide and filipin, which blocks caveolae pathways [25]. Our results suggested that the internalization

• determine the mechanism of nanoparticle uptake, NSCs were pre-treated with inhibitors of endocytosis for 30 min and then incubated with nanoparticles for 48 h in the presence of the inhibitor [25]. The inhibitors were phenylarsine oxide (12 nM), cytochalasin D (60 nM), nocodazole (20 nM) and filipin (0.3 µg

The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

• Yevgeniy R. Davletshin and
• J. Carl Kumaradas

Beilstein J. Nanotechnol. 2016, 7, 869–880, doi:10.3762/bjnano.7.79

• surface of cell [6][7][8][9], modification of gold nanoparticle surfaces to cause binding to each other [10][11] or endocytosis [12]. Nanoparticle assemblies exhibit optical behavior that differs from single particles. The changes in the optical behavior of nanoparticle assemblies are governed by surface

Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels

• Yue Zhang and
• Wan-Xi Yang

Beilstein J. Nanotechnol. 2016, 7, 675–684, doi:10.3762/bjnano.7.60

• , while a significant change occurred in myoblasts after 4 h [87]. Recent studies revealed that hydrodynamic conditions influence the endothelial endocytosis of nanocarriers. By using nanocarriers targeted to PECAM-1, the authors found a flow-stimulated endocytosis of nanocarriers through eliciting

pH-Triggered release from surface-modified poly(lactic-co-glycolic acid) nanoparticles

• Manuel Häuser,
• Klaus Langer and
• Monika Schönhoff

Beilstein J. Nanotechnol. 2015, 6, 2504–2512, doi:10.3762/bjnano.6.260

• taken up by endocytosis. During the process of endocytosis, nanoparticular drug carriers most often end up in endolysosomes with a reduced internal pH value. In order to provide improved accessibility of the drug to the whole cell, membrane destruction of the endolysosomal bilayer would be beneficial

PLGA nanoparticles as a platform for vitamin D-based cancer therapy

• Maria J. Ramalho,
• Joana A. Loureiro,
• Bárbara Gomes,
• Manuela F. Frasco,
• Manuel A. N. Coelho and
• M. Carmo Pereira

Beilstein J. Nanotechnol. 2015, 6, 1306–1318, doi:10.3762/bjnano.6.135

• pancreatic cell lines, S2-013 and hTERT-HPNE, was reported. The in vitro proliferation assay showed that the encapsulation of calcitriol enhanced its antiproliferative activity. The efficient cell internalization by an endocytosis mechanism of PLGA NPs and their rapid endo-lysosomal escape observed in this

• study could explain the benefits of the drug encapsulation in the NPs. Tahara et al. showed that PLGA NPs are efficiently internalized by A549 cells by an endocytosis mechanism, partially mediated by a clathrin [34], which can explain the NP-enhanced calcitriol activity reported in this work. Therefore

Protein corona – from molecular adsorption to physiological complexity

• Lennart Treuel,
• Dominic Docter,
• Michael Maskos and
• Roland H. Stauber

Beilstein J. Nanotechnol. 2015, 6, 857–873, doi:10.3762/bjnano.6.88

• cellular uptake. A possible contribution to this observation is that, in presence of free proteins, the cellular endocytosis machinery was also occupied with internalization of the freely dissolved protein. However, intriguing differences were found between the effects of the different coronae, essentially

• uptake. The notion that rather the kinetics of membrane binding can be affected by the presence and nature of the protein corona, than the kinetics of the actual endocytosis process, allows novel strategies in this context. The role of this finding for the passive uptake of NPs by cells, remains

Influence of gold, silver and gold–silver alloy nanoparticles on germ cell function and embryo development

• Ulrike Taylor,
• Daniela Tiedemann,
• Christoph Rehbock,
• Wilfried A. Kues,
• Stephan Barcikowski and
• Detlef Rath

Beilstein J. Nanotechnol. 2015, 6, 651–664, doi:10.3762/bjnano.6.66

• mattering for fertilisation. The fact that it may be difficult for nanoparticles to enter into these highly specialised cells does not seem unreasonable. Nanoparticles have been observed to enter into somatic cells mostly via endocytosis [59][60], a cellular mechanism which sperm do not possess

Biological responses to nanoscale particles

• Reinhard Zellner

Beilstein J. Nanotechnol. 2015, 6, 380–382, doi:10.3762/bjnano.6.37

• small molecules or nanoparticles can cross membranes with the mediation of specialized proteins, larger nanoparticles exhibit more complex entry mechanisms that are jointly described as endocytosis. The entry mechanism of nanoparticles into living cells and their subsequent trafficking within the cell

Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization

• Lisa Landgraf,
• Ines Müller,
• Peter Ernst,
• Miriam Schäfer,
• Christina Rosman,
• Isabel Schick,
• Oskar Köhler,
• Hartmut Oehring,
• Vladimir V. Breus,
• Thomas Basché,
• Carsten Sönnichsen,
• Wolfgang Tremel and
• Ingrid Hilger

Beilstein J. Nanotechnol. 2015, 6, 300–312, doi:10.3762/bjnano.6.28

• by caveolae-mediated endocytosis and nanoparticles with a size of 40 nm are taken up by clathrin-mediated internalization and macropinocytosis. Our results can be summarized to formulate five general rules, which are further specified in the text and which determine the biocompatibility of

• vacuoles and 4 to 20 nm sized ones in endosomes and lysosomes. A smaller size (4 nm) as well as coupling of polar groups (e.g., NH2) accelerate the uptake and result in the loss of cell viability. Uptake mechanisms In order to assess the mechanisms of endocytosis that are used for the internalization of

• nanoparticles by macrophages after the treatment with genistein [56]. Interestingly, the application of chlorpromazine, selectively affecting clathrin-mediated endocytosis [57][58], led to an increased accumulation of Au@ Fe3O4 and Fe3O4 nanoparticles in HMEC-1 (Figure 6a and Figure 6c). After incubation of