The Effect of shape on Cellular Uptake of Gold Nanoparticles in the forms of Stars, Rods, and Triangles

Zwitterionic carbon dot-encapsulating pH-responsive mesoporous silica nanoparticles for NIR light-triggered photothermal therapy through pH-controllable release

Here, we designed a pH-responsive Indocyanine Green (ICG)-loaded zwitterionic fluorescent carbon dot (CD)-encapsulating mesoporous silica nanoparticle (MSN) for pH-tunable image-guided photothermal therapy.

Tumor heterogeneity and nanoparticle-mediated tumor targeting: the importance of delivery system personalization

After the discovery of the enhanced permeability and retention effect in 1986, it was envisioned that nanoparticle-mediated tumor-targeted delivery of chemotherapeutics would make a radical change in cancer therapy. However, after three decades of extensive research, only a few nanotherapeutics have been approved for clinical use. Although significant advantages of nanomedicines have been demonstrated in pre-clinical studies, clinical outcome was found to be variable. Advanced research has revealed that significant biochemical and structural variations exist between (and among) different tumors. These variations can considerably affect the tumor delivery and efficacy of nanomedicines. Tumor penetration is an important determining factor for positive therapeutic outcome and same nanomedicine can show diverse efficacy against different tumors depending on the extent of tumor accumulation and penetration. Recent research has started shading light on how the tumor variations can influence nanoparticle tumor delivery. These findings indicate that there is no "ideal" design of nanoparticles for exhibiting equally high efficacy against a broad spectrum of tumors. For achieving maximum benefit of the nanotherapeutics, it is necessary to analyze the tumor microenvironment for understanding the biological and structural characteristics of the tumor. Designing of the nanomedicine should be done according to the tumor characteristics. In this comprehensive review, we have first given a brief overview of the design characteristics of nanomedicine which impact their tumor delivery. Then we discussed about the variability in the tumor architecture and how it influences nanomedicine delivery. Finally, we have discussed the possibility of delivery system personalization based on the tumor characteristics.

A Perspective on Nanoparticle Universal Influenza Vaccines

Annually recurring seasonal influenza causes massive economic loss and poses severe threats to public health worldwide. The current seasonal influenza vaccines are the most effective means of preventing influenza infections but possess major weaknesses. Seasonal influenza vaccines require annual updating of the vaccine strains. However, it is an unreachable task to accurately predict the future circulating strains. Vaccines with mismatched strains dramatically compromise the vaccine efficacy. In addition, the seasonal influenza vaccines are ineffective against an unpredictable pandemic. A universal influenza vaccine would overcome these weaknesses of the seasonal vaccines and abolish the threat of influenza pandemics. One approach under investigation is to design influenza vaccine immunogens based on conserved, type-specific amino acid sequences and conformational epitopes, rather than strain-specific. Such vaccines can elicit broadly reactive humoral and cellular immunity. Universal influenza vaccine development has intensively employed nanotechnology because the structural and morphological properties of nanoparticles dramatically improve vaccine immunogenicity and the induced immunity duration. Layered protein nanoparticles can decrease off-target immune responses, fine-tune antigen recognition and processing, and facilitate comprehensive immune response induction. Herein, we review the designs of effective nanoparticle universal influenza vaccines, the recent discoveries of specific nanoparticle features that contribute to immunogenicity enhancement, and recent progress in clinical trials.

Impact of nanogold morphology on interactions with human serum

Gold nanoparticles (AuNPs) of differing shapes are of great interest to researchers due to their unique optical properties, making them potentially powerful theranostic tools. The synthesis of AuNPs is performed frequently, however the assessment of biological activity for each nanoparticle is not always commonplace. While it is thought that physicochemical parameters such as shape may play an important role in dictating the outcomes of interactions which take place at the nano-bio interface, a systematic approach to the assessment of nanomaterials has not been widely adopted. In this study, the interaction between human serum albumin (HSA) and four similar sized but different shaped AuNPs (spherical, rod shaped, prismatic and cubic) synthesised using a common chemical surfactant (CTAB), is presented. Using fluorescence spectroscopy it is shown that all AuNPs exhibit static binding with HSA, however the shape affects both the affinity and strength of the binding. Rod shaped nanoparticles were found to have the highest binding strength and affinity. Conversely, shapes with large flat planar surfaces such as prisms and cubes were shown to have reduced accessibility to the site of the fluorophore within the structure of HSA. The differences observed help to provide a better understanding of the effect of shape on AuNP-protein interactions - knowledge which may be applied to the development of AuNPs for future biological applications.

Surface-Active Fluorinated Quantum Dots for Enhanced Cellular Uptake

Fluorescent nanoparticles, such as quantum dots, hold great potential for biomedical applications, mainly sensing and bioimaging. However, the inefficient cell uptake of some nanoparticles hampers their application in clinical practice. Here, the effect of the modification of the quantum dot surface with fluorinated ligands to increase their surface activity and, thus, enhance their cellular uptake was explored.

Track analysis of a synchrotron X-ray photoelectric nanoradiator by in situ fluorescence imaging of reactive oxygen species: comparative study of gold and iron oxide nanoparticles

The emission of fluorescent X-rays and low-energy electrons by mid-/high-Z nanoparticles upon irradiation with either X-ray photons or high-energy ion beams is referred to as the nanoradiator effect (NRE). A track analysis of NRE was performed using reactive oxygen species (ROS) gels, to which macrophages containing gold nanoparticles (AuNPs) were attached, together with single-cell irradiation of the intracellular nanoparticles from a microbeam of synchrotron X-rays, and the range and distribution of ^\bulletOH and O₂^{ \bullet - } produced were compared with those of the Fe-nanoradiator by magnetite nanoparticles (FeONP, Fe₃O₄). The Au-nanoradiator generated ROS fluorescence to a greater depth and wider angle with respect to the incident X-rays than that of the Fe-nanoradiator. The ROS-oxidant fluorescence intensity ratios of ^\bulletOH to O₂^{ \bullet - } were different for the AuNPs and FeONPs, reflecting different relative yields of electrons and fluorescent X-rays from NRE. In the region immediately (<100 µm) below the irradiated cell, ^\bulletOH-radicals were distributed mainly along two or three tracks in the depth direction in the FeONP- or AuNP-ROS gel. In contrast, O₂^{ \bullet - } was scattered more abundantly in random directions in the AuNP-ROS gel than in the FeONP-ROS gel. Track analysis of X-ray photoelectric nanoradiator radiation showed a different range of dose distribution and relative emission compositions between Au- and Fe-nanoradiators, suggesting more extensive damage beyond a single cell containing AuNPs than one containing FeONPs.

Tumor Microenvironment Targeted Nanotherapy

Recent developments in nanotechnology have brought new approaches to cancer diagnosis and therapy. While enhanced permeability and retention effect promotes nano-chemotherapeutics extravasation, the abnormal tumor vasculature, high interstitial pressure and dense stroma structure limit homogeneous intratumoral distribution of nano-chemotherapeutics and compromise their imaging and therapeutic effect. Moreover, heterogeneous distribution of nano-chemotherapeutics in non-tumor-stroma cells damages the non-tumor cells, and interferes with tumor-stroma crosstalk. This can lead not only to inhibition of tumor progression, but can also paradoxically induce acquired resistance and facilitate tumor cell proliferation and metastasis. Overall, the tumor microenvironment plays a vital role in regulating nano-chemotherapeutics distribution and their biological effects. In this review, the barriers in tumor microenvironment, its consequential effects on nano-chemotherapeutics, considerations to improve nano-chemotherapeutics delivery and combinatory strategies to overcome acquired resistance induced by tumor microenvironment have been summarized. The various strategies viz., nanotechnology based approach as well as ligand-mediated, redox-responsive, and enzyme-mediated based combinatorial nanoapproaches have been discussed in this review.

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

High-performance bioceramics are required for preventing failure and prolonging the life-time of bone grafting scaffolds and osseous implants. The proper identification and development of materials with extended functionalities addressing socio-economic needs and health problems constitute important and critical steps at the heart of clinical research. Recent findings in the realm of ion-substituted hydroxyapatite (HA) could pave the road towards significant developments in biomedicine, with an emphasis on a new generation of orthopaedic and dentistry applications, since such bioceramics are able to mimic the structural, compositional and mechanical properties of the bone mineral phase. In fact, the fascinating ability of the HA crystalline lattice to allow for the substitution of calcium ions with a plethora of cationic species has been widely explored in the recent period, with consequent modifications of its physical and chemical features, as well as its functional mechanical and in vitro and in vivo biological performance. A comprehensive inventory of the progresses achieved so far is both opportune and of paramount importance, in order to not only gather and summarize information, but to also allow fellow researchers to compare with ease and filter the best solutions for the cation substitution of HA-based materials and enable the development of multi-functional biomedical designs. The review surveys preparation and synthesis methods, pinpoints all the explored cation dopants, and discloses the full application range of substituted HA. Special attention is dedicated to the antimicrobial efficiency spectrum and cytotoxic trade-off concentration values for various cell lines, highlighting new prophylactic routes for the prevention of implant failure. Importantly, the current in vitro biological tests (widely employed to unveil the biological performance of HA-based materials), and their ability to mimic the in vivo biological interactions, are also critically assessed. Future perspectives are discussed, and a series of recommendations are underlined.

Analytical methodology for studying cellular uptake, processing and localization of gold nanoparticles

Interactions of gold nanoparticles (AuNPs) with live cells are known to exert a great impact on their functions, including cell signalling, genomic, proteomic, and metabolomic processes. Modern analytical techniques applied to studying nanoparticle-cell interactions are to improve our understanding of the mode of action of AuNPs, which is essential for their approval in disease therapeutics. Such methods may vary depending on what step of particle internalization is in question, i.e., cellular uptake, intracellular transport (accompanying by changes in the chemical state), translocation to different cell compartments, interaction with relevant subcellular structures and localization. This review focuses on the implementation and critical assessment of advanced analytical methodologies to investigate the cellular processing of AuNPs. Also addressed is a sought-after issue of accounting in in-vitro studies for a chemical form in which the AuNPs enter the cell in vivo.

Amelioration effects of nanoencapsulated triterpenoids from petri dish-cultured Antrodia cinnamomea on reproductive function of diabetic male rats

PURPOSE

Nanoencapsulated triterpenoids from petri dish-cultured Antrodia cinnamomea (PAC) and its amelioration effects on reproductive function in diabetic rats were investigated.

MATERIALS AND METHODS

PAC encapsulated in silica-chitosan nanoparticles (Nano-PAC) was prepared by the biosilicification method. The diabetic condition in male Sprague Dawley rats was induced by high-fat diet and streptozotocin (STZ). Three different doses of Nano-PAC (4, 8, and 20 mg/kg) were administered for 6 weeks. Metformin and control of nanoparticles (Nano-con) were taken as positive and negative controls, respectively.

RESULTS

The average particle size was ~79.46±1.63 nm, and encapsulation efficiency was ~73.35%±0.09%. Nano-PAC administration improved hyperglycemia and insulin resistance. In addition, Nano-PAC ameliorated the morphology of testicular seminiferous tubules, sperm morphology, motility, ROS production, and mitochondrial membrane potential. Superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) antioxidant, as well as testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were increased, whereas proinflammatory cytokines TNF-α, IL-6, and IFN-γ were decreased.

CONCLUSION

In the present study, we successfully nanoencapsulated PAC and found that a very low dosage of Nano-PAC exhibited amelioration effects on the reproductive function of diabetic rats.

Interaction of Positively Charged Gold Nanoparticles with Cancer Cells Monitored by an in Situ Label-Free Optical Biosensor and Transmission Electron Microscopy

Functionalized nanoparticles (NPs) can penetrate into living cells and vesicles, opening up an extensive range of novel directions. For example, NPs are intensively employed in targeted drug delivery and biomedical imaging. However, the real-time kinetics and dynamics of NP-living cell interactions remained uncovered. In this study, we in situ monitored the cellular uptake of gold NPs-functionalized with positively charged alkaline thiol-into surface-adhered cancer cells, by using a high-throughput label-free optical biosensor employing resonant waveguide gratings. The characteristic kinetic curves upon NP exposure of cell-coated biosensor surfaces were recorded and compared to the kinetics of NP adsorption onto bare sensor surfaces. We demonstrated that from the above kinetic information, one can conclude about the interactions between the living cells and the NPs. Real-time biosensor data suggested the cellular uptake of the functionalized NPs by an active process. It was found that positively charged particles penetrate into the cells more effectively than negatively charged control particles, and the optimal size for the cellular uptake of the positively charged particles is around 5 nm. These conclusions were obtained in a cost-effective, fast, and high-throughput manner. The fate of the NPs was further revealed by electron microscopy on NP-exposed and subsequently fixed cells, well confirming the results obtained by the biosensor. Moreover, an ultrastructural study demonstrated the involvement of the endosomal-lysosomal system in the uptake of functionalized NPs and suggested the type of the internalization pathway.

Toxicological investigations of "naked" and polymer-entrapped AOT-based gold nanotriangles

Negatively charged ultrathin gold nanotriangles (AuNTs) were synthesized in a vesicular dioctyl sodium sulfosuccinate (AOT)/phospholipid-based template phase. These "naked" AuNTs with localized surface plasmon resonances in the NIR region at about 1300 nm and special photothermal properties are of particular interest for imaging and hyperthermia of cancerous tissues. For these kinds of applications the toxicity and the cellular uptake of the AuNTs is of outstanding importance. Therefore, this study focuses on the toxicity of "naked" AOT-stabilized AuNTs compared to polymer-coated AuNTs. Polymeric coating consisted of non-modified hyperbranched poly(ethyleneimine) (PEI), maltose-modified poly(ethyleneimine) (PEI-Mal) and heparin. The toxicological experiments were carried out with two different cell lines (embryonic kidney carcinoma cell line HEK293T and NK-cell leukemia cell line YTS). This study revealed that the heparin-coating of AuNTs improved biocompatibility by a factor of 50 when compared to naked AuNTs. Of note, the highest nontoxic concentration of the AuNTs coated with PEI and PEI-Mal is drastically decreased. Overall, this is mainly triggered by the different surface charges of polymeric coatings. Therefore, AuNTs coated with heparin were selected to carry out uptake studies. Their promising high biocompatibility and cellular uptake may open future studies in the field of biomedical applications.

Intracellular Transport of Silver and Gold Nanoparticles and Biological Responses: An Update

Medicine, food, and cosmetics represent the new promising applications for silver (Ag) and gold (Au) nanoparticles (NPs). AgNPs are most commonly used in food and cosmetics; conversely, the main applications of gold NPs (AuNPs) are in the medical field. Thus, in view of the risk of accidentally or non-intended uptake of NPs deriving from the use of cosmetics, drugs, and food, the study of NPs⁻cell interactions represents a key question that puzzles researchers in both the nanomedicine and nanotoxicology fields. The response of cells starts when the NPs bind to the cell surface or when they are internalized. The amount and modality of their uptake depend on many and diverse parameters, such as NPs and cell types. Here, we discuss the state of the art of the knowledge and the uncertainties regarding the biological consequences of AgNPs and AuNPs, focusing on NPs cell uptake, location, and translocation. Finally, a section will be dedicated to the most currently available methods for qualitative and quantitative analysis of intracellular transport of metal NPs.

Probing cellular uptake and tracking of differently shaped gelatin-coated gold nanoparticles inside of ovarian cancer cells by two-photon excited photoluminescence analyzed by fluorescence lifetime imaging (FLIM)

Nowadays, the non-linear optical effect of two-photon excited (TPE) fluorescence has recently grown in interest in recent years over other optical imaging method, due to improved 3D spatial resolution, deep penetrability and less photodamage of living organism owing to the excitation in near-infrared region (NIR). In parallel, gold nanoparticles (AuNPs) have gain considerable attention for NIR TPE bio-imaging applications due to their appealing ability to generate strong intrinsic photoluminescence (PL). Here, we demonstrate the capability of differently shaped gelatin-coated AuNPs to perform as reliable label-free contrast agents for the non-invasive NIR imaging of NIH:OVCAR-3 ovary cancer cells via TPE Fluorescence Lifetime Imaging Microscopy (FLIM). Examination of the spectroscopic profile of the intrinsic signals exhibited by AuNPs inside cells confirm the plasmonic nature of the emitted PL, while the evaluation of time-dependent profile of the TPE PL signal under continuous irradiation indicates the photo-stability of the signal revealing simultaneously a photo-blinking behavior. Finally, we assess the dependence of the TPE PL signal on laser excitation power and wavelength in view of contributing to a better understanding of plasmonic TPE PL in biological media towards the improvement of TPE FLIM imaging applications based on AuNPs.

Self-Assembled Tetrahedral DNA Nanostructures Promote Neural Stem Cell Proliferation and Neuronal Differentiation

Stem cell-based therapy is considered a promising approach for the repair of nervous tissues. Neural stem cells (NSCs) cannot proliferate or differentiate efficiently; hence, different biomaterials have been explored to improve NSC proliferation and differentiation. However, these agents either had low bioavailability or poor biocompatibility. In this work, our group investigated the effects of tetrahedral DNA nanostructures (TDNs), a novel DNA biological material, on the self-renew and differentiation of neuroectodermal (NE-4C) stem cells. We observed that TDN treatment promoted self-renew of the stem cells via activating the Wnt/β -catenin pathway. In addition, our findings suggested that NE-4C stem cells' neuronal differentiation could be promoted effectively by TDNs via inhibiting the notch signaling pathway. In summary, this is the first report about the effects of TDNs on the proliferation and differentiation of NE-4C stem cells and the results demonstrate that TDNs have a great potential in nerve tissue regeneration.

Internalization studies on zeolite nanoparticles using human cells

Zeolites are crystalline porous materials with a regular framework which have non-toxic effects on a variety of human cell lines and have been explored for cell imaging and drug delivery. Understanding the interaction between zeolite nanoparticles and cells is imperative for improving their potentialities, since the process of internalization of these particles is still poorly understood. In this study, the intracellular trafficking and internalization kinetics of zeolite L into breast cancer cells and normal epithelial mammary cells were analysed using scanning electron microscopy (SEM), confocal microscopy and transmission electron microscopy (TEM). We also studied the involvement of endocytic pathways using two pharmacological inhibitors, chlorpromazine and dynasore. Zeolite nanoparticles were taken up by both cell types and the cellular uptake was fast, and started immediately after 5 min of incubation. Interestingly, the uptake was dependent on the cell type since in breast cancer cells it was faster and more efficient, with a higher number of nanoparticles being internalized by cancer cells over time, compared to that in the epithelial mammary cells. TEM results showed that the internalized nanoparticles were mainly localized in the cell vacuoles. The data obtained upon using endocytic pharmacological inhibitors suggest that the zeolite L uptake is mediated by caveolin.

Overcoming drug-resistant lung cancer by paclitaxel loaded tetrahedral DNA nanostructures

Drug-loaded tetrahedron DNA nanostructures and their cytotoxic effect on drug-resistant cells have been studied.

The photophysicochemical behavior of symmetric and asymmetric zinc phthalocyanines, surface assembled onto gold nanotriangles

The synthesis of a novel asymmetric ZnPc, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(ii), complex3, is reported.

Improved Fenton Therapy Using Cancer Cell Hydrogen Peroxide

Fenton cancer therapy as a new methodology for the treatment of tumour cells is largely restricted owing to the low stability, high aggregation, and poor selectivity of reported nanoparticles. In this study, an improved approach for the selective destruction of cancer cells is reported. Metal–organic framework (MOF) nanoparticles were synthesized and reduced via a hydrothermal method, and then PEGylated through the surface-initiated atom transfer radical polymerization (SI-ATRP) reaction to produce a PEGylated reduced MOF (P@rMOF). The ratio of PEG to nanoparticles was used to optimize the size and aggregation of the nanoparticles, with 2P@rMOF (2 : 1 mass ratio) having the smallest hydrodynamic diameter. The nanoparticles were further conjugated with folic acid for cell targeting. In vitro cell uptake experiments demonstrated that the internalization of 2P@rMOF-FA nanoparticles into cancer cells (HeLa) was almost 3-fold that of normal cells (NIH-3T3). In the presence of 2P@rMOF-FA, the HeLa cell viability decreased dramatically to 22 %, whereas the NIH-3T3 cell viability remained higher than 80 % after 24 h incubation. The selectivity index for 2P@rMOF-FA is 4.48, which is significantly higher than those reported in the literature for similar strategies. This work thus demonstrates the most stable and selective nanoparticle system for the treatment of cancer cells using the cell’s own H2O2.

A growing world of small things: a brief review on the nanostructured vaccines

Vaccines are the most cost-effective intervention in the management of infectious disease. Much of what we perceive as quality of life is related to a good health status and disease absence, for which vaccines are substantially responsible. Nonetheless, there are many infectious diseases for which no vaccine solution is available. That could be due to limitations of the classic approaches to vaccine development, including inactivated, subunit and attenuated vaccines. Nanostructured immunogens belong to a class of nonclassic vaccines in which nanostructures are loaded with antigen-related molecules. Here, we briefly review important features of the nanostructured vaccines – mainly those based in carbon nanotubes and gold nanorods – and discuss their use to prevent infectious diseases, especially those caused by viruses.

Synthesis and characterization of cystamine conjugated chitosan-SS-mPEG based 5-Fluorouracil loaded polymeric nanoparticles for redox responsive drug release

The principle objective of this study was to develop and characterize redox responsive polymeric nanoparticles (PNPs) as a stimuli responsive drug delivery system. The chitosan-cystamine-methoxy poly(ethylene glycol) (CH-SS-mPEG) copolymer was synthesized by conjugation of cystamine appended chitosan with carboxylic acid-terminated mPEG and characterized by FTIR, ¹H NMR, XRD analysis and colorimetric assay. This copolymer could be formulated as 5-Fluorouracil (5-FU) loaded PNPs and the characteristics of PNPs were evaluated. Moreover, folic acid functionalized PNPs were prepared for folate receptor targeted drug delivery. Drug release studies indicated that the redox sensitive PNPs were stable in physiological condition while quickly releasing 5-FU in the trigger of redox potential due to the cleavage of the disulfide linkages. In contrast, less quantity of drug was released from the reduction insensitive chitosan-g-methoxy poly(ethylene glycol) (CH-g-mPEG) based PNPs under both reduction sensitive and non-reductive conditions. From the cytotoxicity studies, it was evident that 5-FU loaded PNPs had higher toxicity against MCF7 cells when compared to 5-FU free PNPs. Subsequently, cellular uptake studies showed significantly increased internalization of folic acid attached PNPs. In conclusion, the developed PNPs appeared to be of great promise in redox responsive drug release for targeted drug delivery.

Biofilm dispersal using nitric oxide loaded nanoparticles fabricated by photo-PISA: influence of morphology

The morphology of nitric oxide loaded polymeric nanoparticles is a significant parameter that influence the nitric oxide release and dispersal of bacterial biofilms.