Wide varieties of cationic nanoparticles induce defects in supported lipid bilayers

A study on the effect of fluorescently stained micro(nano)plastics on the full life history of Skeletonema costatum

As a new type of environmental pollutant, micro(nano)plastics have become a research hotspot in recent years, and their effects on the full life history of marine microalgae have not been studied. To investigate the effects of micro(nano)plastics on the growth, photosynthesis, physiological morphology and interaction of microalgae during the full life cycle, we selected fluorescently stained polystyrene (PS) plastic microbeads as the target pollutant. By sampling and testing the growth rate, photosynthesis and physiological morphology parameters of algal species, the influence of different concentrations of PS (10, 50 and 100 mg/L) and different particle sizes (0.1, 0.5 and 1 μm) on the full life history of Skeletonema costatum (S. costatum) was investigated. The results showed that after adding PS (particle sizes of 0.5 and 1 μm), the response of S. costatum showed a dual character, while adding the same kind of microplastics (MPs) with a particle size of 0.1 μm inhibited S. costatum throughout the full life cycle. Compared with previous studies, short-term experimental data may overestimate the true ecological risks of MPs. In addition, 0.1 μm fluorescent-stained MPs obviously accumulated around the microalgae, indicating that MPs mainly adhered to the surface of algal cells and may enter the food chain by direct or indirect ways, which can cause negative effects on the aquatic ecosystem. This study supports a more accurate assessment of the true risk of MPs to marine aquatic ecosystems.

Assessment and accumulation of microplastics in the Indian riverine systems: Risk assessment and implications of translocation across the water-to-fish continuum

Microplastic (MP) pollution has engulfed global aquatic systems, and the concerns about microplastic translocation and bioaccumulation in fish and other aquatic organisms are now an unpleasant truth. In the past few years, MP pollution in freshwater systems, particularly rivers and subsequently in freshwater organisms, especially in fish, has caught the attention of researchers. Rivers provide livelihood to approximately 40 % of the global population through food and potable water. Hence, assessment of emerging contaminants like microplastics in rivers and the associated fauna is crucial. This study assessed microplastics (MPs) in fish, sediment and freshwater samples across the third largest riverine system of peninsular India, the Mahanadi River. The number concentrations of MPs measured in water, sediment and fish ranged from 337.5 ± 54.4-1333.3 ± 557.2 MPs/m3, 14.7 ± 3.7-69.3 ± 10.1 MPs/kg. Dry weight and 0.4-3.2 MPs/Fish, respectively. Surprisingly, MPs were found in every second fish sample, with a higher MP number in the gut than in the gills. Black and blue coloured filaments with <0.5 mm size were the dominant MPs with polypropylene and polyethylene polymers in abundance. The Polymer Hazard Index (PHI) and the Potential Ecological Risk Index (PERI) studies revealed that the majority of the sampling sites fell in Risk category V (dangerous category). An irregular trend in the MP concentration was observed downstream of the river, though relatively elevated MP concentrations in water and fish samples were observed downstream of the river. t-Distributed Stochastic Neighbour Embedding (t-SNE) unveiled distinct patterns in MP distribution with a higher similarity exhibited in the MPs found in fish gill and gut samples, unlike water and sediment, which shared certain characteristics. The findings in the current study contribute to filling the knowledge gap of MP assessment and accumulation in global freshwater systems and highlight the microplastic contamination and accumulation in fish with its potential implications on human health.

Meta-analysis for systematic review of global micro/nano-plastics contamination versus various freshwater microalgae: Toxicological effect patterns, taxon-specific response, and potential eco-risks

Micro/nano-plastics (MNPs), as emerging persistent pollutants, are threatening freshwater ecosystems worldwide. Microalgae are important primary producers at the base of trophic level and susceptible to MNPs contamination, possibly resulting in further contamination in higher trophic levels and water quality. This study conducted a systematic review of 1071 observations from 63 publications, utilizing meta-analysis and subgroup analysis to investigate the toxicological effect patterns of MNPs parameters (size, concentration, and type) on microalgae. We also explored the potential eco-risks of certain specific MNPs parameters and subtle variations in the response of various microalgae taxa to MNPs. Results suggested that microplastics significantly inhibited microalgal photosynthesis, while nano-plastics induced more severe cell membrane damage and promoted toxin-release. Within a certain range of concentrations (0∼50 mg/L), rising MNPs concentration progressively inhibited microalgal growth and chlorophyll-a content, and progressively enhanced toxin-release. Among MNPs types, polyamide caused higher growth inhibition and more severe lipid peroxidation, and polystyrene induced more toxin-release, whereas polyethylene terephthalate and polymethyl methacrylate posed minimal effects on microalgae. Moreover, Bacillariophyta growth was inhibited most significantly, while Chlorophyta displayed strong tolerance and Cyanophyta possessed strong adaptive and exceptional resilience. Particularly, Komvophoron, Microcystis, Nostoc, Scenedesmus, and Gomphonema were more tolerant and might dominate freshwater microalgal communities under MNPs contamination. These results are crucial for acquiring the fate of freshwater microalgae under various MNPs contamination, identifying dominant microalgae, and reasonably assessing and managing involved eco-risks.

Delivering CRISPR to the HIV-1 reservoirs

Human immunodeficiency virus type 1 (HIV-1) infection is well known as one of the most complex and difficult viral infections to cure. The difficulty in developing curative strategies arises in large part from the development of latent viral reservoirs (LVRs) within anatomical and cellular compartments of a host. The clustered regularly interspaced short palindromic repeats/ CRISPR-associated protein 9 (CRISPR/Cas9) system shows remarkable potential for the inactivation and/or elimination of integrated proviral DNA within host cells, however, delivery of the CRISPR/Cas9 system to infected cells is still a challenge. In this review, the main factors impacting delivery, the challenges for delivery to each of the LVRs, and the current successes for delivery to each reservoir will be discussed.

Gold Nanoparticles (AuNPs)-Toxicity, Safety and Green Synthesis: A Critical Review

In recent years, the extensive exploration of Gold Nanoparticles (AuNPs) has captivated the scientific community due to their versatile applications across various industries. With sizes typically ranging from 1 to 100 nm, AuNPs have emerged as promising entities for innovative technologies. This article comprehensively reviews recent advancements in AuNPs research, encompassing synthesis methodologies, diverse applications, and crucial insights into their toxicological profiles. Synthesis techniques for AuNPs span physical, chemical, and biological routes, focusing on eco-friendly "green synthesis" approaches. A critical examination of physical and chemical methods reveals their limitations, including high costs and the potential toxicity associated with using chemicals. Moreover, this article investigates the biosafety implications of AuNPs, shedding light on their potential toxic effects on cellular, tissue, and organ levels. By synthesizing key findings, this review underscores the pressing need for a thorough understanding of AuNPs toxicities, providing essential insights for safety assessment and advancing green toxicology principles.

Progress in regulating inflammatory biomaterials for intervertebral disc regeneration

Intervertebral disc degeneration (IVDD) is rising worldwide and leading to significant health issues and financial strain for patients. Traditional treatments for IVDD can alleviate pain but do not reverse disease progression, and surgical removal of the damaged disc may be required for advanced disease. The inflammatory microenvironment is a key driver in the development of disc degeneration. Suitable anti-inflammatory substances are critical for controlling inflammation in IVDD. Several treatment options, including glucocorticoids, non-steroidal anti-inflammatory drugs, and biotherapy, are being studied for their potential to reduce inflammation. However, anti-inflammatories often have a short half-life when applied directly and are quickly excreted, thus limiting their therapeutic effects. Biomaterial-based platforms are being explored as anti-inflammation therapeutic strategies for IVDD treatment. This review introduces the pathophysiology of IVDD and discusses anti-inflammatory therapeutics and the components of these unique biomaterial platforms as comprehensive treatment systems. We discuss the strengths, shortcomings, and development prospects for various biomaterials platforms used to modulate the inflammatory microenvironment, thus providing guidance for future breakthroughs in IVDD treatment.

Anti-osteosarcoma trimodal synergistic therapy using NiFe-LDH and MXene nanocomposite for enhanced biocompatibility and efficacy

Osteosarcoma is usually resistant to immunotherapy and, thus primarily relies on surgical resection and high-dosage chemotherapy. Unfortunately, less invasive or toxic therapies such as photothermal therapy (PTT) and chemodynamic therapy (CDT) generally failed to show satisfactory outcomes. Adequate multimodal therapies with proper safety profiles may provide better solutions for osteosarcoma. Herein, a simple nanocomposite that synergistically combines CDT, PTT, and chemotherapy for osteosarcoma treatment was fabricated. In this composite, small 2D NiFe-LDH flakes were processed into 3D hollow nanospheres via template methods to encapsulate 5-Fluorouracil (5-FU) with high loading capacity. The nanospheres were then adsorbed onto larger 2D Ti3C2 MXene monolayers and finally shielded by bovine serum albumin (BSA) to form 5-FU@NiFe-LDH/Ti3C2/BSA nanoplatforms (5NiTiB). Both in vitro and in vivo data demonstrated that the 5-FU induced chemotherapy, NiFe-LDH driven chemodynamic effects, and MXene-based photothermal killing collectively exhibited a synergistic "all-in-one" anti-tumor effect. 5NiTiB improved tumor suppression rate from <5% by 5-FU alone to ∼80.1%. This nanotherapeutic platform achieved higher therapeutic efficacy with a lower agent dose, thereby minimizing side effects. Moreover, the composite is simple to produce, enabling the fine-tuning of dosages to suit different requirements. Thus, the platform is versatile and efficient, with potential for further development.

Maltodextrin-Nanoparticles as a Delivery System for Nasal Vaccines: A Review Article

Nanoparticles are increasingly being studied as antigen delivery systems for immunization with nasal vaccines. The addition of adjuvants is still generally required in many nanoparticle formulations, which can induce potential side effects owing to mucosal reactogenicity. In contrast, maltodextrin nanoparticles do not require additional immunomodulators, and have been shown to be efficient vaccine delivery systems. In this review, the development of maltodextrin nanoparticles is presented, specifically their physico-chemical properties, their ability to load antigens and deliver them into airway mucosal cells, and the extent to which they trigger protective immune responses against bacterial, viral, and parasitic infections. We demonstrate that the addition of lipids to maltodextrin nanoparticles increases their potency as a vaccine delivery system for nasal administration.

Synthesis and biophysical evaluation of carbosilane dendrimers as therapeutic siRNA carriers

Gene therapy presents an innovative approach to the treatment of previously incurable diseases. The advancement of research in the field of nanotechnology has the potential to overcome the current limitations and challenges of conventional therapy methods, and therefore to unlocking the full potential of dendrimers for use in the gene therapy of neurodegenerative disorders. The blood-brain barrier (BBB) poses a significant challenge when delivering therapeutic agents to the central nervous system. In this study, we investigated the biophysical properties of dendrimers and their complexes with siRNA directed against the apolipoprotein E (APOE) gene to identify an appropriate nanocarrier capable of safely delivering the cargo across the BBB. Our study yielded valuable insights into the complexation process, stability over time, the mechanisms of interaction, the influence of dendrimers on the oligonucleotide's spatial structure, and the potential cytotoxic effects on human cerebral microvascular endothelium cells. Based on our findings, we identified that the dendrimer G3Si PEG6000 was an optimal candidate for further research, potentially serving as a nanocarrier capable of safely delivering therapeutic agents across the BBB for the treatment of neurodegenerative disorders.

Polyoxometalate-Decorated Gold Nanoparticles Inhibit β-Amyloid Aggregation and Cross the Blood-Brain Barrier in a µphysiological Model

Alzheimer's disease is characterized by a combination of several neuropathological hallmarks, such as extracellular aggregates of beta amyloid (Aβ). Numerous alternatives have been studied for inhibiting Aβ aggregation but, at this time, there are no effective treatments available. Here, we developed the tri-component nanohybrid system AuNPs@POM@PEG based on gold nanoparticles (AuNPs) covered with polyoxometalates (POMs) and polyethylene glycol (PEG). In this work, AuNPs@POM@PEG demonstrated the inhibition of the formation of amyloid fibrils, showing a 75% decrease in Aβ aggregation in vitro. As it is a potential candidate for the treatment of Alzheimer's disease, we evaluated the cytotoxicity of AuNPs@POM@PEG and its ability to cross the blood-brain barrier (BBB). We achieved a stable nanosystem that is non-cytotoxic below 2.5 nM to human neurovascular cells. The brain permeability of AuNPs@POM@PEG was analyzed in an in vitro microphysiological model of the BBB (BBB-on-a-chip), containing 3D human neurovascular cell co-cultures and microfluidics. The results show that AuNPs@POM@PEG was able to cross the brain endothelial barrier in the chip and demonstrated that POM does not affect the barrier integrity, giving the green light to further studies into this system as a nanotherapeutic.

Polyethylenimine (PEI) in gene therapy: Current status and clinical applications

Polyethlyenimine (PEI) was introduced 1995 as a cationic polymer for nucleic acid delivery. PEI and its derivatives are extensively used in basic research and as reference formulations in the field of polymer-based gene delivery. Despite its widespread use, the number of clinical applications to date is limited. Thus, this review aims to consolidate the past applications of PEI in DNA delivery, elucidate the obstacles that hinder its transition to clinical use, and highlight potential prospects for novel iterations of PEI derivatives. The present review article is divided into three sections. The first section examines the mechanism of action employed by PEI, examining fundamental aspects of cellular delivery including uptake mechanisms, release from endosomes, and transport into the cell nucleus, along with potential strategies for enhancing these delivery phases. Moreover, an in-depth analysis is conducted concerning the mechanism underlying cellular toxicity, accompanied with approaches to overcome this major challenge. The second part is devoted to the in vivo performance of PEI and its application in various therapeutic indications. While systemic administration has proven to be challenging, alternative localized delivery routes hold promise, such as treatment of solid tumors, application as a vaccine, or serving as a therapeutic agent for pulmonary delivery. In the last section, the outcome of completed and ongoing clinical trials is summarized. Finally, an expert opinion is provided on the potential of PEI and its future applications. PEI-based formulations for nucleic acid delivery have a promising potential, it will be an important task for the years to come to introduce innovations that address PEI-associated shortcomings by introducing well-designed PEI formulations in combination with an appropriate route of administration.

Gene silencing in adult Popillia japonica through feeding of double-stranded RNA (dsRNA) complexed with branched amphiphilic peptide capsules (BAPCs)

Gene silencing by feeding double-stranded (dsRNA) holds promise as a novel pest management strategy. Nonetheless, degradation of dsRNA in the environment and within the insect gut, as well as inefficient systemic delivery are major limitations to applying this strategy. Branched amphiphilic peptide capsules (BAPCs) complexed with dsRNA have been used to successfully target genes outside and inside the gut epithelium upon ingestion. This suggests that BAPCs can protect dsRNA from degradation in the gut environment and successfully shuttle it across gut epithelium. In this study, our objectives were to 1) Determine whether feeding on BAPC-dsRNA complexes targeting a putative peritrophin gene of P. japonica would result in the suppression of gut peritrophin synthesis, and 2) gain insight into the cellular uptake mechanisms and transport of BAPC-dsRNA complexes across the larval midgut of P. japonica. Our results suggest that BAPC-dsRNA complexes are readily taken up by the midgut epithelium, and treatment of the tissue with endocytosis inhibitors effectively suppresses intracellular transport. Further, assessment of gene expression in BAPC- peritrophin dsRNA fed beetles demonstrated significant downregulation in mRNA levels relative to control and/or dsRNA alone. Our results demonstrated that BAPCs increase the efficacy of gene knockdown relative to dsRNA alone in P. japonica adults. To our knowledge, this is the first report on nanoparticle-mediated dsRNA delivery through feeding in P. japonica.

Energy metabolism response induced by microplastic for marine dinoflagellate Karenia mikimotoi

Microplastic contaminations threaten the entire marine ecosystem and cause severe ecological stress. This study explored the energy metabolism change of Karenia mikimotoi under exposure to nanoplastics (NPs) and microplastics (MPs) (65 nm, 100 nm, and 1 μm polystyrene (PS), and 100 nm polymethyl methacrylate (PMMA)) at a concentration of 10 mg L^-1. Membrane potential, esterase activity, polysaccharide content, and ATPase activity were detected to assess the energy metabolism of K. mikimotoi under MPs/NPs exposure. Transcriptome and metabolomic analyses were used to investigate the intrinsic mechanisms of energy metabolism changes. Smaller PS particles caused greater damage to the cell membrane potential, increased the polysaccharide content, and resulted in a heavier weakening of the ATPase enzymatic activity in K. mikimotoi cells, suggesting that smaller-sized PS had more influence on esterase activity and energy metabolism than the bigger-sized PS. The results evidenced that energy metabolism relates to the size and type of MPs/NPs, and nano-scale plastic particles could induce greater metabolic changes.

Surface-Functionalized Polystyrene Nanoparticles Alter the Transmembrane Potential via Ion-Selective Pores Maintaining Global Bilayer Integrity

Although nanoplastics have well-known toxic effects toward the environment and living organisms, their molecular toxicity mechanisms, including the nature of nanoparticle-cell membrane interactions, are still under investigation. Here, we employ dynamic light scattering, quartz crystal microbalance with dissipation monitoring, and electrophysiology to investigate the interaction between polystyrene nanoparticles (PS NPs) and phospholipid membranes. Our results show that PS NPs adsorb onto lipid bilayers creating soft inhomogeneous films that include disordered defects. PS NPs form an integral part of the generated channels so that the surface functionalization and charge of the NP determine the pore conductive properties. The large difference in size between the NP diameter and the lipid bilayer thickness (∼60 vs ∼5 nm) suggests a particular and complex lipid-NP assembly that is able to maintain overall membrane integrity. In view of this, we suggest that NP-induced toxicity in cells could operate in more subtle ways than membrane disintegration, such as inducing lipid reorganization and transmembrane ionic fluxes that disrupt the membrane potential.

Surface and Structure of Phosphatidylcholine Membranes Reconstructed with CoFe2O4 Nanoparticles

Structural changes in phosphatidylcholine lipid membranes caused by the introduction of insoluble CoFe₂O₄ nanoparticles (NPs) are analyzed. Changes in nuclear magnetic resonance spectrum, infrared spectrum, and ionic conductivity of membranes are observed with the addition of NPs. The presence of NPs in membranes is proved by atomic force and magnetic force microscopy. Structural changes in the membranes in the vicinity of the lipid C-O bonds caused by NPs are observed by Scanning near-field optical microscopy. Analysis of nuclear magnetic resonance (NMR) spectra allowed us to identify the affected atomic groups in the membrane surface layers. Conductivity measurements of the bilayer membranes were performed in DC as well as in time-resolved modes. Hydrophobic NPs stimulate surface distortion and creation of pores, which depending on NP concentration leads to an increase in the ionic conductivity of membranes. Concentration dependence demonstrating percolation threshold was analyzed in the frame of the fractal theory approach.

Organelle-targeted therapies: a comprehensive review on system design for enabling precision oncology

Cancer is a major threat to human health. Among various treatment methods, precision therapy has received significant attention since the inception, due to its ability to efficiently inhibit tumor growth, while curtailing common shortcomings from conventional cancer treatment, leading towards enhanced survival rates. Particularly, organelle-targeted strategies enable precise accumulation of therapeutic agents in organelles, locally triggering organelle-mediated cell death signals which can greatly reduce the therapeutic threshold dosage and minimize side-effects. In this review, we comprehensively discuss history and recent advances in targeted therapies on organelles, specifically including nucleus, mitochondria, lysosomes and endoplasmic reticulum, while focusing on organelle structures, organelle-mediated cell death signal pathways, and design guidelines of organelle-targeted nanomedicines based on intervention mechanisms. Furthermore, a perspective on future research and clinical opportunities and potential challenges in precision oncology is presented. Through demonstrating recent developments in organelle-targeted therapies, we believe this article can further stimulate broader interests in multidisciplinary research and technology development for enabling advanced organelle-targeted nanomedicines and their corresponding clinic translations.

Protease-activated indocyanine green nanoprobes for intraoperative NIR fluorescence imaging of primary tumors

Tumor-targeted fluorescent probes in the near-infrared spectrum can provide invaluable information about the location and extent of primary and metastatic tumors during intraoperative procedures to ensure no residual tumors are left in the patient's body. Even though the first fluorescence-guided surgery was performed more than 50 years ago, it is still not accepted as a standard of care in part due to the lack of efficient and non-toxic targeted probes approved by regulatory agencies around the world. Herein, we report protease-activated cationic gelatin nanoparticles encapsulating indocyanine green (ICG) for the detection of primary breast tumors in murine models with high tumor-to-background ratios. Upon intravenous administration, these nanoprobes remain optically silent due to the energy resonance transfer among the bound ICG molecules. As the nanoprobes extravasate and are exposed to the acidic tumor microenvironment, their positive surface charges increase, facilitating cellular uptake. The internalized nanoprobes are activated upon proteolytic degradation of gelatin to allow high contrast between the tumor and normal tissue. Since both gelatin and ICG are FDA-approved for intravenous administration, this activatable nanoprobe can lead to quick clinical adoption and improve the treatment of patients undergoing image-guided cancer surgery.

The humic acid-like substances released from Microcystis aeruginosa contribute to defending against smaller-sized microplastics

Microplastics (MPs) are ubiquitous in freshwater ecosystems, but knowledge of their effects on extracellular polymeric substance (EPS) produced by algae is poorly understood. The components in specific EPS fractions of Microcystis respond when exposed to MPs is also still unclear. In this study, the responses of Microcystis aeruginosa under polystyrene (PS) microplastic exposure were studied over 17 days of cultivation, using 0.1 μm and 1.0 μm sized PS at three concentration gradients (1, 10 and 100 mg/L). Results indicate that algal growth significantly increased using the 0.1 and 1.0 μm PS at a high concentration (100 mg/L) on day 17, with growth rates of 74.71% ± 0.94% and 35.87% ± 1.23%, respectively. All tested PS had a maximum inhibitory effect on the photosynthesis on day 5, but the inhibition of photosynthetic activity by 0.1 μm PS alleviated after 13 days of exposure, indicating recovery of microalgae from the toxic environment. The two PS sizes at 100 mg/L concentration triggered EPS release in the latter stage of the experiment; meanwhile, fluorescence EEM analysis showed that smaller-sized PS (0.1 μm) at various doses noticeably increased humic acid-like substances in tightly bound EPS (TB-EPS) fractions on day 17. Our findings showed that EPS release and humic acid-like substances secretion of Microcystis likely can resist MPs exposure. The results provide new insights into the toxicity mechanism of MPs on freshwater microalgae, as well as understanding the ecological risks of microplastics.

Non-Viral Delivery of Gene Therapy to the Tendon

The tendon, as a compact connective tissue, is difficult to treat after an acute laceration or chronic degeneration. Gene-based therapy is a highly efficient strategy for diverse diseases which has been increasingly applied in tendons in recent years. As technology improves by leaps and bounds, a wide variety of non-viral vectors have been manufactured that attempt to have high biosecurity and transfection efficiency, considered to be a promising treatment modality. In this review, we examine the unwanted biological barriers, the categories of applicable genes, and the introduction and comparison of non-viral vectors. We focus on lipid-based nanoparticles and polymer-based nanoparticles, differentiating between them based on their combination with diverse chemical modifications and scaffolds.

Self-fluorescence property of octa-arginine functionalized hydroxyapatite nanoparticles aids in studying their intracellular fate in R1 ESCs

Deciphering the endocytosis mechanisms of nanoparticle entry in cells is crucial to understand the fate of nanoparticles and the biological activity of the transported cargo. Such studies require the use of reporter agents such as fluorescent markers. Previously, we have reported the synthesis of self-fluorescent HAp nanoparticles as efficient nucleic acid delivery agents in prokaryotic and eukaryotic cells. Here, we show the application of biocompatible self-fluorescent nano delivery vehicle based on HAp and CPP- octa-arginine as an efficient system to study the mechanisms of intracellular fate of a gene delivery agent. The pathway of octa-arginine functionalized HAp NP (R8HNP) and HAp NP uptake in R1 ESCs was elucidated using confocal microscopy with the help of endocytic inhibitors. The NPs mainly enter R1 ESCs by clathrin mediated and macropinocytosis pathways. It was established that the NPs escape endosomal degradation by proton sponge effect owing to their ability to buffer the pH and trigger osmotic rupture. The functionalization of CPP, effectively enhanced the internalization and endosomal escape in R1 ESCs. The detailed results of these studies are outlined in this manuscript.

Theoretical evaluation of poly(amidoamine) dendrimers with different peripheral groups as a purinethol drug delivery system in aqueous medium

In this work, density functional theory calculations were used to study the association of PUR with amine- and acetyl-terminated PAMAM dendrimers considering implicit solvent effect at neutral and low pH conditions. Frontier molecular orbitals' analysis indicates that the electronic properties of dendrimers are extremely sensitive to the presence of PUR molecule at both neutral and low pH conditions. Encapsulation of PUR molecule into the both amine- and acetyl-terminated PAMAM dendrimers leads to a Gibbs free energy of (ΔG) - 20.25 kcal.mol^-1 at physiological pH. The corresponding ΔG values reduce to the - 1.45 and - 0.91 kcal.mol^-1 at low pH, indicating that the drug molecule is released easily at low pH. The calculated recovery times for amine- (3.87 ×10² and 3.87 ×10², at neutral and low pH, respectively) and acetyl-terminated (5.34 ×10¹⁰ and 1.81 ×10^-1, at neutral and low pH, respectively) dendrimers suggest that acetylation can improve the release pattern of drug molecule.

Analysis of cell-nanoparticle interactions and imaging of in vitro labeled cells showing barcorded endosomes using fluorescent thiol-organosilica nanoparticles surface-functionalized with polyethyleneimine

Biomedical imaging using cell labeling is an important technique to visualize cell dynamics in the body. To label cells, thiol-organosilica nanoparticles (thiol-OS) containing fluorescein (thiol-OS/Flu) and rhodamine B (thiol-OS/Rho) were surface-functionalized with polyethyleneimine (PEI) (OS/Flu-PEI and OS/Rho-PEI) with 4 molecular weights (MWs). We hypothesized PEI structures such as brush, bent brush, bent lie-down, and coiled types on the surface depending on MWs based on dynamic light scattering and thermal gravimetric analyses. The labeling efficacy of OS/Flu-PEIs was dependent on the PEI MW and the cell type. A dual-particle administration study using thiol-OS and OS-PEIs revealed differential endosomal sorting of the particles depending on the surface of the NPs. The endosomes in the labeled cells using OS/Flu-PEI and thiol-OS/Rho revealed various patterns of fluorescence termed barcoded endosomes. The cells labeled with OS-PEI in vitro were administrated to mice intraperitoneally after in situ labeling of peritoneal cells using thiol-OS/Rho. The in vitro labeled cells were detected and identified in cell aggregates in vivo seamlessly. The labeled cells with barcoded endosomes were also identified in cell aggregates. Biomedical imaging of in vitro OS-PEI-labeled cells combined with in situ labeled cells showed high potential for observation of cell dynamics.

Microplastics can alter phytoplankton community composition

Microplastic pollution is a growing concern globally due to the risks they may pose to ecological communities. Phytoplankton are key ecological community in aquatic ecosystems providing both energy to food webs and have critical roles in ecosystem functions such as carbon cycling. To date studies on how microplastics effect phytoplankton have largely been limited to laboratory exposure studies using monocultures of algae. It remains unknown how the structure of phytoplankton communities will be influenced by growing microplastic pollution. The aim of this study was to determine how different concentrations microplastic fibers influence phytoplankton community structure. Two six-day microcosm studies were conducted testing the response of the phytoplankton community to low, medium, and high microplastics concentrations on the Georges River, Australia. The results showed the highest concentrations of microplastics significantly altered the structure phytoplankton community. These differences were largely driven by increased abundances of cyanobacteria taxa Aphanocapsa and Pseudanabaena, and to a lesser extent reduced abundances of taxa including Crucigenia and Chlamydmonas. There were no significant differences between controls and the low and medium treatments in either experiment. The high concentrations used in this experiment whilst likely rare in the environment are environmentally relevant and equivalent to some of more polluted ecosystems. The results highlight the potential risk to food webs and ecosystem functioning through altering the dynamics of primary production and provide evidence for further study examining the response of ecological communities to microplastics in the environment.

The Role of in silico Research in Developing Nanoparticle-Based Therapeutics

Nanoparticles (NPs) hold great potential as therapeutics, particularly in the realm of drug delivery. They are effective at functional cargo delivery and offer a great degree of amenability that can be used to offset toxic side effects or to target drugs to specific regions in the body. However, there are many challenges associated with the development of NP-based drug formulations that hamper their successful clinical translation. Arguably, the most significant barrier in the way of efficacious NP-based drug delivery systems is the tedious and time-consuming nature of NP formulation—a process that needs to account for downstream effects, such as the onset of potential toxicity or immunogenicity, in vivo biodistribution and overall pharmacokinetic profiles, all while maintaining desirable therapeutic outcomes. Computational and AI-based approaches have shown promise in alleviating some of these restrictions. Via predictive modeling and deep learning, in silico approaches have shown the ability to accurately model NP-membrane interactions and cellular uptake based on minimal data, such as the physicochemical characteristics of a given NP. More importantly, machine learning allows computational models to predict how specific changes could be made to the physicochemical characteristics of a NP to improve functional aspects, such as drug retention or endocytosis. On a larger scale, they are also able to predict the in vivo pharmacokinetics of NP-encapsulated drugs, predicting aspects such as circulatory half-life, toxicity, and biodistribution. However, the convergence of nanomedicine and computational approaches is still in its infancy and limited in its applicability. The interactions between NPs, the encapsulated drug and the body form an intricate network of interactions that cannot be modeled with absolute certainty. Despite this, rapid advancements in the area promise to deliver increasingly powerful tools capable of accelerating the development of advanced nanoscale therapeutics. Here, we describe computational approaches that have been utilized in the field of nanomedicine, focusing on approaches for NP design and engineering.

Facilitating trehalose entry into hRBCs at 4 °C by alkylated ε-poly(L-lysine) for glycerol-free cryopreservation

Currently, glycerol is a conventional cryoprotectant of human red blood cells (hRBCs), but the time-consuming thawing and deglycerolization processes are essential before transfusion. Much of the research up to now has been conducted on the delivery of impermeable trehalose to hRBCs at 37 °C, but the cryoprotective effect of trehalose and deterioration of cells still remain challenging. Encouraged by the interaction of hydrophobic or cationic groups on cell membranes and osmotic stabilization, herein, we propose a novel cryopreservation system to facilitate trehalose entry into hRBCs at 4 °C and pH 7.4. High intracellular trehalose contents and cryosurvival of hRBCs were achieved with small function variations via the assistance of self-assembled nanoparticles of alkylated ε-poly(L-lysine) (ε-PL) along with poly(vinyl pyrrolidone) (PVP). The effect of amphipathic alkylated ε-PL with various alkyl chains and grafting ratios on membrane perturbation with protection of PVP was systematically investigated. Overall, by the combination of alkylated ε-PL and PVP, the intracellular trehalose could be enhanced to 109.7 ± 6.1 mM and subsequently hRBC cryosurvival reached 91.7 ± 5.5%, significantly higher than those containing trehalose only, 11.9 ± 1.1 mM and 50.0 ± 2.1%, respectively. It was observed that the biocompatible trehalose-loading system could benefit glycerol-free cryopreservation of hRBCs and also provide a feasible way for impermeable biomacromolecule delivery.

How the Physicochemical Properties of Manufactured Nanomaterials Affect Their Performance in Dispersion and Their Applications in Biomedicine: A Review

The growth in novel synthesis methods and in the range of possible applications has led to the development of a large variety of manufactured nanomaterials (MNMs), which can, in principle, come into close contact with humans and be dispersed in the environment. The nanomaterials interact with the surrounding environment, this being either the proteins and/or cells in a biological medium or the matrix constituent in a dispersion or composite, and an interface is formed whose properties depend on the physicochemical interactions and on colloidal forces. The development of predictive relationships between the characteristics of individual MNMs and their potential practical use critically depends on how the key parameters of MNMs, such as the size, shape, surface chemistry, surface charge, surface coating, etc., affect the behavior in a test medium. This relationship between the biophysicochemical properties of the MNMs and their practical use is defined as their functionality; understanding this relationship is very important for the safe use of these nanomaterials. In this mini review, we attempt to identify the key parameters of nanomaterials and establish a relationship between these and the main MNM functionalities, which would play an important role in the safe design of MNMs; thus, reducing the possible health and environmental risks early on in the innovation process, when the functionality of a nanomaterial and its toxicity/safety will be taken into account in an integrated way. This review aims to contribute to a decision tree strategy for the optimum design of safe nanomaterials, by going beyond the compromise between functionality and safety.

Biocompatible Nanomaterials in Food Science, Technology, and Nutrient Drug Delivery: Recent Developments and Applications

Nanomaterials exist as potential biocompatible materials in nature and are being synthesized to provide extraordinary characteristics in various food industry sectors. Synthesis of biocompatible nanomaterials requires modification in the shape, density, and size of nanomaterials. Biocompatible nanomaterials are synthesized to reduce toxicity, decrease adverse effects in the gastrointestinal tract, and enhance immune response. Nanomaterials can target organs and tissues. Nanomaterials are found to be effectively compatible by interacting with functional foods and nutraceuticals. Applications of these nanomaterials are novel strategies in food industries such as food safety, food processing, food quality, food packaging, and food labeling. Various functions like detection of toxins and pathogens; production of biocompatible packaging; enhancement in color, flavor, and aroma; processing edible film, and sensing authenticity of food product are being accomplished with no toxicity. This review provides a systematic study on the biocompatibility of nanomaterials. It highlights the synthesis of biocompatible nanomaterials and advanced functions of these nanomaterials in the production area, processing industry, safety improvement, quality control, edible packaging films, biocompatibility, current developments, legislations and regulations for Nano-products, health and safety concerns, toxicity and public perceptions for use of nanomaterials.

Polymer Nanoparticles Enhance Irreversible Electroporation In Vitro

Expanding the volume of an irreversible electroporation treatment typically necessitates an increase in pulse voltage, number, duration, or repetition. This study investigates the addition of polyethylenimine nanoparticles (PEI-NP) to pulsed electric field treatments, determining their combined effect on ablation size and voltages. U118 cells in an in vitro 3D cell culture model were treated with one of three pulse parameters (with and without PEI-NPs) which are representative of irreversible electroporation (IRE), high frequency irreversible electroporation (H-FIRE), or nanosecond pulsed electric fields (nsPEF). The size of the ablations were compared and mapped onto an electric field model to describe the electric field required to induce cell death. Analysis was conducted to determine the role of PEI-NPs in altering media conductivity, the potential for PEI-NP degradation following pulsed electric field treatment, and PEI-NP uptake. Results show there was a statistically significant increase in ablation diameter for IRE and H-FIRE pulses with PEI-NPs. There was no increase in ablation size for nsPEF with PEI-NPs. This all occurs with no change in cell media conductivity, no observable degradation of PEI-NPs, and moderate particle uptake. These results demonstrate the synergy of a combined cationic polymer nanoparticle and pulsed electric field treatment for the ablation of cancer cells. These results set the foundation for polymer nanoparticles engineered specifically for irreversible electroporation.

Active Nanomotors Surpass Passive Nanomedicines: Current Progress and Challenges

Artificial nanomotors show advantages over traditional nanomedicines in biomedical applications due to their active locomotion by converting various energy sources into mechanical force in situ. Currently, nanomotors have attracted wide...

Microplastics hamper the fertilization success of a broadcast spawning bivalve through reducing gamete collision and gamete fusion efficiency

By employing external fertilization (broadcast spawning) as a mating strategy, the gametes and subsequent fertilization of various marine invertebrates are directly subjected to pollution. Although microplastics (MPs) are ubiquitous in marine environments, their potential effects on the fertilization of broadcast spawners remain largely unknown. Therefore in this study, the impacts of polystyrene MPs on the fertilization success of broadcast spawning bivalve (Tegillarca granosa) were investigated. In order to reveal the underlying mechanisms affecting fertilization, the sperm swimming performance, sperm ATP status, sperm viability, DNA integrity, gamete collision probability, gamete fusion efficiency, enzymatic antioxidants, and key ion transport enzyme activities were analyzed. The results showed that MPs weakened the sperm swimming performance through reducing ATP production and cell viability, thus leading to the decreased probability of gamete collision. Furthermore, MPs affected ion transport in the gametes by inducing oxidative stress, which resulted in gamete fusion failure. In conclusion, this study demonstrates that MPs could significantly decrease the fertilization success of T. granosa through reducing gamete collision and lowering gamete fusion efficiency.

Water-soluble PANI:PSS designed for spontaneous non-disruptive membrane penetration and direct intracellular photothermal damage on bacteria

The major challenge in the field of antibacterial agents is to overcome the low-permeability of bacteria cell membranes that protects the cells against diverse drugs. In this work, water-soluble polyaniline (PANI)-poly (p-styrenesulfonic acid) (PSS) (PANI:PSS) is found to spontaneously penetrate bacteria cellular membranes in a non-disruptive way, leaving no evidence of membrane poration/disturbance or cell death, thus avoiding side effects caused by cationic ammonia groups in traditional ammonia-containing antibacterial agents. For aqueous synthesis, which is important for biocompatibility, the polymer is synthesized via an enzyme-mimetic route relying on the catalysis of a nanozyme. Owing to its fluorescent properties, the localization of as-prepared PANI:PSS is determined by the confocal microscope, and the results confirm its rapid entry into bacteria. Under 808 nm near-infrared (NIR) irradiation, the internalized PANI:PSS generates local hyperthermia and destroys bacteria highly efficiently from inside the cells due to its excellent photothermal effects. Staphylococcus aureus (S. aureus), M ethicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) could be effectively eliminated as well as the corresponding bacterial biofilms. Results of in vivo antibacterial experiments demonstrate excellent antibacterial activities of the water-soluble PANI:PSS without side effects. Therefore, the prepared water-soluble polymer in this study has great potential in the treatment of various bacterial infections.

Role of proteins in the biosynthesis and functioning of metallic nanoparticles

Proteins are known to play important roles in the biosynthesis of metallic nanoparticles (NPs), which are biological substitutes for conventionally used chemical capping and stabilizing agents. When a pristine nanoparticle comes in contact with a biological media or system, a bimolecular layer is formed on the surface of the nanoparticle and is primarily composed of proteins. The role of proteins in the biosynthesis and further uptake, translocation, and bio-recognition of nanoparticles is documented in the literature. But, a complete understanding has not been achieved concerning the mechanism for protein-mediated nanoparticle biosynthesis and the role proteins play in the interaction and recognition of nanoparticles, aiding its uptake and assimilation into the biological system. This review critically evaluates the knowledge and gaps in the protein-mediated biosynthesis of nanoparticles. In particular, we review the role of proteins in multiple facets of metallic nanoparticle biosynthesis, the interaction of proteins with metallic nanoparticles for recognition and interaction with cells, and the toxic potential of protein-nanoparticle complexes when presented to the cell.

Targeting the Inside of Cells with Biologicals: Chemicals as a Delivery Strategy

Delivering macromolecules into the cytosol or nucleus is possible in vitro for DNA, RNA and proteins, but translation for clinical use has been limited. Therapeutic delivery of macromolecules into cells requires overcoming substantially higher barriers compared to the use of small molecule drugs or proteins in the extracellular space. Breakthroughs like DNA delivery for approved gene therapies and RNA delivery for silencing of genes (patisiran, ONPATTRO^®, Alnylam Pharmaceuticals, Cambridge, MA, USA) or for vaccination such as the RNA-based coronavirus disease 2019 (COVID-19) vaccines demonstrated the feasibility of using macromolecules inside cells for therapy. Chemical carriers are part of the reason why these novel RNA-based therapeutics possess sufficient efficacy for their clinical application. A clear advantage of synthetic chemicals as carriers for macromolecule delivery is their favourable properties with respect to production and storage compared to more bioinspired vehicles like viral vectors or more complex drugs like cellular therapies. If biologicals can be applied to intracellular targets, the druggable space is substantially broadened by circumventing the limited utility of small molecules for blocking protein–protein interactions and the limitation of protein-based drugs to the extracellular space. An in depth understanding of the macromolecular cargo types, carrier types and the cell biology of delivery is crucial for optimal application and further development of biologicals inside cells. Basic mechanistic principles of the molecular and cell biological aspects of cytosolic/nuclear delivery of macromolecules, with particular consideration of protein delivery, are reviewed here. The efficiency of macromolecule delivery and applications in research and therapy are highlighted.

The effects and mechanisms of polystyrene and polymethyl methacrylate with different sizes and concentrations on Gymnodinium aeruginosum

In this study, Gymnodinium aeruginosum was exposed to polystyrene (PS) and polymethyl methacrylate (PMMA) of three particle sizes (0.1 μm, 1.0 μm and 100 μm) and two concentrations (10 mg/L and 75 mg/L) for 96 h. The density of algae cells, the endpoints that reactive oxygen species (ROS), total protein (TP), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT), scanning and transmission electron microscopy (SEM and TEM) were used to explore the toxicity mechanism to the microalgae. At a concentration of 75 mg/L, the 96 h inhibition ratios (IR) with particle sizes of 0.1 μm, 1.0 μm and 100 μm on G. aeruginosum were 55.9%, 63.7% and 6.0% for PS, respectively, and 3.0%, 4.1% and -0.6% for PMMA, respectively. The most significant changes in ROS, TP, MDA, SOD and CAT were observed at 75 mg/L 1.0 μm of PS when treated for 96 h. When exposed to nanoplastics (NPs) and microplastics (MPs), the algae cells were damaged, and the antioxidant system was activated. Extracellular polymeric substance (EPS) could help to detoxify the algae. In general, PS was more toxic than PMMA. The toxicity of small MNPs (0.1 μm and 1.0 μm) was related to the concentrations, while large MNPs (100 μm) did not.

Polycation-Mediated Transfection: Mechanisms of Internalization and Intracellular Trafficking

Polyplex-mediated gene transfection is now in its' fourth decade of serious research, but the promise of polyplex-mediated gene therapy has yet to fully materialize. Only approximately one in a million applied plasmids actually expresses. A large part of this is due to an incomplete understanding of the mechanism of polyplex transfection. There is an assumption that internalization must follow a canonical mechanism of receptor mediated endocytosis. Herein, we present arguments that untargeted (and most targeted) polyplexes do not utilize these routes. By incorporating knowledge of syndecan-polyplex interactions, we can show that syndecans are the "target" for polyplexes. Further, it is known that free polycations (which disrupt cell-membranes by acid-catalyzed hydrolysis of phospholipid esters) are necessary for (untargeted) endocytosis. This can be incorporated into the model to produce a novel mechanism of endocytosis, which fits the observed phenomenology. After membrane translocation, polyplex containing vesicles reach the endosome after diffusing through the actin mesh below the cell membrane. From there, they are acidified and trafficked toward the lysosome. Some polyplexes are capable of escaping the endosome and unpacking, while others are not. Herein, it is argued that for some polycations, as acidification proceeds the polyplexes excluding free polycations, which disrupt the endosomal membrane by acid-catalyzed hydrolysis, allowing the polyplex to escape. The polyplex's internal charge ratio is now insufficient for stability and it releases plasmids which diffuse to the nucleus. A small proportion of these plasmids diffuse through the nuclear pore complex (NPC), with aggregation being the major cause of loss. Those plasmids that have diffused through the NPC will also aggregate, and this appears to be the reason such a small proportion of nuclear plasmids express mRNA. Thus, the structural features which promote unpacking in the endosome and allow for endosomal escape can be determined, and better polycations can be designed.

Phospholipid Membrane Formation Templated by Coacervate Droplets

We report the formation of coacervate-supported phospholipid membranes by hydrating a dried lipid film in the presence of coacervate droplets. Coacervate-supported membranes were characterized by fluorescence imaging, polarization, fluorescence recovery after photobleaching of labeled lipids, lipid quenching experiments, and solute uptake experiments. Our findings are consistent with the presence of lipid membranes around the coacervates, with many droplets fully coated by what appear to be continuous lipid bilayers. In contrast to traditional giant lipid vesicles formed by gentle hydration in the absence of coacervates, the coacervate-templated membrane vesicles are more uniform in size, shape, and apparent lamellarity. Due to their fully coacervate model cytoplasm, these simple artificial cells are macromolecularly crowded and can be easily pre-loaded with high concentrations of proteins or nucleic acids. Within the same population, in addition to coacervate droplets having intact lipid membrane coatings, other coacervate droplets are coated with membranes having defects or pores that permit solute entry, and some are coated with multilayered membranes. Membranes surrounding protein-based coacervate droplets provided protection from a protease added to the external solution. The simplicity of producing artificial cells having a coacervate model cytoplasm surrounded by a model membrane is at the same time interesting as a potential mechanism for prebiotic protocell formation and appealing for biotechnology. We anticipate that such structures could serve as a new type of model system for understanding interactions between intracellular phases and cell or organelle membranes, which are implicated in a growing number of processes ranging from neurotransmission to signaling.

Cellular Uptake of Three Different Nanoparticles in an Inflammatory Arthritis Scenario versus Normal Conditions

Nanoparticles (NPs) have wide potential applications in the biomedical field. To promote targeted and controlled delivery of encapsulated drugs, it is fundamentally important to understand the factors regulating NP uptake by different cells. Thus, the goal of the present study is to assess the internalization rates of different NPs under normal and proinflammatory states in primary human articular chondrocytes (hACs), human umbilical vein endothelial cells (EA), and human monocytes (THP-1). Here, we compared chitosan-hyaluronic acid (Ch-HA) polymeric NPs, methoxypolyethylene glycol amine-glutathione-palmitic acid (mPEG-GSH_n-PA) micelles, and cholesterol/l-α-phosphatidylcholine/DSPE-PEG-Mal (Chol/EPC/DSPE-PEG-Mal) unilamellar liposomes (LUVs). Our results reveal the importance of surface charge and chemistry in determining the levels of NP internalization. Under normal conditions, the cellular uptake was ≈30% for Ch-HA NPs and ≈100% for mPEG-GSH_n-PA micelles and Chol/EPC/DSPE-PEG-Mal LUVs. A proinflammatory cell state promoted a higher uptake of the Ch-HA NPs by EA cells (93% after 24 h). Since the therapeutic efficacy of the NP-loaded cargo is dependent on trafficking routes after cellular internalization, we tested their internalization pathways. Accordingly, caveolae-mediated endocytosis or energy-independent non-endocytic pathways, which circumvent lysosomal degradation, were accomplished in hACs and EA by LUVs and in M1 polarized macrophages by micelles. The present outcomes highlight the importance of considering cellular uptake and internalization pathways by the target cell when designing functional NPs for therapeutic applications.

Biodistribution of Exosomes and Engineering Strategies for Targeted Delivery of Therapeutic Exosomes

Exosomes are cell-secreted nano-sized vesicles which deliver diverse biological molecules for intercellular communication. Due to their therapeutic potential, exosomes have been engineered in numerous ways for efficient delivery of active pharmaceutical ingredients to various target organs, tissues, and cells. In vivo administered exosomes are normally delivered to the liver, spleen, kidney, lung, and gastrointestinal tract and show rapid clearance from the blood circulation after systemic injection. The biodistribution and pharmacokinetics (PK) of exosomes can be modulated by engineering various factors such as cellular origin and membrane protein composition of exosomes. Recent advances accentuate the potential of targeted delivery of engineered exosomes even to the most challenging organs including the central nervous system. Major breakthroughs have been made related to various imaging techniques for monitoring in vivo biodistribution and PK of exosomes, as well as exosomal surface engineering technologies for inducing targetability. For inducing targeted delivery, therapeutic exosomes can be engineered to express various targeting moieties via direct modification methods such as chemically modifying exosomal surfaces with covalent/non-covalent bonds, or via indirect modification methods by genetically engineering exosome-producing cells. In this review, we describe the current knowledge of biodistribution and PK of exosomes, factors determining the targetability and organotropism of exosomes, and imaging technologies to monitor in vivo administered exosomes. In addition, we highlight recent advances in strategies for inducing targeted delivery of exosomes to specific organs and cells.

Association Mechanism of Peptide-Coated Metal Nanoparticles with Model Membranes: A Coarse-Grained Study

Functionalized metal nanoparticles (NPs) hold great promise as innovative tools in nanomedicine. However, one of the main challenges is how to optimize their association with the cell membrane, which is critical for their effective delivery. Recent findings show high cellular uptake rates for NPs coated with the polycationic cell-penetrating peptide gH625-644 (gH), although the underlying internalization mechanism is poorly understood. Here, we use extended coarse-grained simulations and free energy calculations to study systems that simultaneously include metal NPs, peptides, lipids, and sterols. In particular, we investigate the first encounter between multicomponent model membranes and 2.5 nm metal NPs coated with gH (gHNPs), based on the evidence from scanning transmission electron microscopy. By comparing multiple membrane and (membranotropic) NP models, we found that gHNP internalization occurs by forming an intermediate state characterized by specific stabilizing interactions formed by peptide-coated nanoparticles with multicomponent model membranes. This association mechanism is mainly characterized by interactions of gH with the extracellular solvent and the polar membrane surface. At the same time, the NP core interacts with the transmembrane (cholesterol-rich) fatty phase.

The cell membrane as the barrier in the defense against nanoxenobiotics: Zinc oxide nanoparticles interactions with native and model membrane of melanoma cells

Currently, we are dealing with ever-increasing pollution of the environment with metal and metal oxide nanoparticles. One type of these, zinc oxide nanoparticles (ZnO-NPs), are increasingly used in areas such as cosmetology, electrical engineering, medicine, and even in the food and textile industries. As a consequence, ZnO-NPs may enter the human body in many ways. Their influence on the body is still not clear. Here, we define the mechanism of the initial toxicity of ZnO-NPs to cells based on interaction with the lipid part of the native and model cell membrane. The selected cell lines react differently to contact with nanoparticles. We found a disruption of the native membranes of B16-F0 cells and to a lesser extent of COLO 679. In turn, the membrane of COLO 679 cells was more peroxidated, and cell viability was much lower. A model of the lipid part of the membrane was created for B16-F0 cells and compared with previously published studies on immune cells. On the basis of physicochemical parameters obtained for individual lipids and a mix representing the native membrane of the tested cells, we concluded that exposure to nanoparticles resulted in a change within the model membranes (specifically with the polar parts of lipids). The greatest interaction has been noticed between ZnO-NPs and zwitterionic phospholipids (PC and PE), cholesterol, and negatively charged phosphatidylglycerol. Assessing the interactions between the membrane and nanoparticles will help to better understand the first steps of its toxicity mechanism.

Hydrogel-Induced Cell Membrane Disruptions Enable Direct Cytosolic Delivery of Membrane-Impermeable Cargo

Intracellular delivery of membrane-impermeable cargo offers unique opportunities for biological research and the development of cell-based therapies. Despite the breadth of available intracellular delivery tools, existing protocols are often suboptimal and alternative approaches that merge delivery efficiency with both biocompatibility, as well as applicability, remain highly sought after. Here, a comprehensive platform is presented that exploits the unique property of cationic hydrogel nanoparticles to transiently disrupt the plasma membrane of cells, allowing direct cytosolic delivery of uncomplexed membrane-impermeable cargo. Using this platform, which is termed Hydrogel-enabled nanoPoration or HyPore, the delivery of fluorescein isothiocyanate (FITC)-dextran macromolecules in various cancer cell lines and primary bovine corneal epithelial cells is convincingly demonstrated. Of note, HyPore demonstrates efficient FITC-dextran delivery in primary human T cells, outperforming state-of-the-art electroporation-mediated delivery. Moreover, the HyPore platform enables cytosolic delivery of functional proteins, including a histone-binding nanobody as well as the enzymes granzyme A and Cre-recombinase. Finally, HyPore-mediated delivery of the MRI contrast agent gadobutrol in primary human T cells significantly improves their T₁ -weighted MRI signal intensities compared to electroporation. Taken together, HyPore is proposed as a straightforward, highly versatile, and cost-effective technique for high-throughput, ex vivo manipulation of primary cells and cell lines.

Toxicity of gold nanoparticles (AuNPs): A review

Gold nanoparticles are a kind of nanomaterials that have received great interest in field of biomedicine due to their electrical, mechanical, thermal, chemical and optical properties. With these great potentials came the consequence of their interaction with biological tissues and molecules which presents the possibility of toxicity. This paper aims to consolidate and bring forward the studies performed that evaluate the toxicological aspect of AuNPs which were categorized into in vivo and in vitro studies. Both indicate to some extent oxidative damage to tissues and cell lines used in vivo and in vitro respectively with the liver, spleen and kidney most affected. The outcome of these review showed small controversy but however, the primary toxicity and its extent is collectively determined by the characteristics, preparations and physicochemical properties of the NPs. Some studies have shown that AuNPs are not toxic, though many other studies contradict this statement. In order to have a holistic inference, more studies are required that will focus on characterization of NPs and changes of physical properties before and after treatment with biological media. So also, they should incorporate controlled experiment which includes supernatant control Since most studies dwell on citrate or CTAB-capped AuNPs, there is the need to evaluate the toxicity and pharmacokinetics of functionalized AuNPs with their surface composition which in turn affects their toxicity. Functionalizing the NPs surface with more peculiar ligands would however help regulate and detoxify the uptake of these NPs.

Switching Cytolytic Nanopores into Antimicrobial Fractal Ruptures by a Single Side Chain Mutation

Disruption of cell membranes is a fundamental host defense response found in virtually all forms of life. The molecular mechanisms vary but generally lead to energetically favored circular nanopores. Here, we report an elaborate fractal rupture pattern induced by a single side-chain mutation in ultrashort (8-11-mers) helical peptides, which otherwise form transmembrane pores. In contrast to known mechanisms, this mode of membrane disruption is restricted to the upper leaflet of the bilayer where it exhibits propagating fronts of peptide-lipid interfaces that are strikingly similar to viscous instabilities in fluid flow. The two distinct disruption modes, pores and fractal patterns, are both strongly antimicrobial, but only the fractal rupture is nonhemolytic. The results offer wide implications for elucidating differential membrane targeting phenomena defined at the nanoscale.

Influence of Surface Ligand Molecular Structure on Phospholipid Membrane Disruption by Cationic Nanoparticles

Cationic nanoparticles are known to interact with biological membranes and often cause serious membrane damage. Therefore, it is important to understand the molecular mechanism for such interactions and the factors that impact the degree of membrane damage. Previously, we have demonstrated that spatial distribution of molecular charge at cationic nanoparticle surfaces plays an important role in determining the cellular uptake and membrane damage of these nanoparticles. In this work, using diamond nanoparticles (DNPs) functionalized with five different amine-based surface ligands and small phospholipid unilamellar vesicles (SUVs), we further investigate how chemical features and conformational flexibility of surface ligands impact nanoparticle/membrane interactions. ³¹P-NMR T₂ relaxation measurements quantify the mobility changes in lipid dynamics upon exposing the SUVs to functional DNPs, and coarse-grained molecular dynamics simulations further elucidate molecular details for the different modes of DNP-SUV interactions depending on the surface ligands. Collectively, our results show that the length of the hydrophobic segment and conformational flexibility of surface ligands are two key factors that dictate the degree of membrane damage by the DNP, while the amount of surface charge alone is not predictive of the strength of interaction.

Specific and nondisruptive interaction of guanidium-functionalized gold nanoparticles with neutral phospholipid bilayers

Understanding and controlling the interaction between nanoparticles and biological entities is fundamental to the development of nanomedicine applications. In particular, the possibility to realize nanoparticles capable of directly targeting neutral lipid membranes would be advantageous to numerous applications aiming at delivering nanoparticles and their cargos into cells and biological vesicles. Here, we use experimental and computational methodologies to analyze the interaction between liposomes and gold nanoparticles (AuNPs) featuring cationic headgroups in their protecting monolayer. We find that in contrast to nanoparticles decorated with other positively charged headgroups, guanidinium-coated AuNPs can bind to neutral phosphatidylcholine liposomes, inducing nondisruptive membrane permeabilization. Atomistic molecular simulations reveal that this ability is due to the multivalent H-bonding interaction between the phosphate residues of the liposome's phospholipids and the guanidinium groups. Our results demonstrate that the peculiar properties of arginine magic, an effect responsible for the membranotropic properties of some naturally occurring peptides, are also displayed by guanidinium-bearing functionalized AuNPs.

A proton/macromolecule-sensing approach distinguishes changes in biological membrane permeability during polymer/lipid-based nucleic acid delivery

Endosomal escape is crucial for the delivery of nucleic acids. However, the understanding of the underlying mechanisms is still deficient. In this work, we explored the effects of lipid- and polymer-based transfection reagents on the permeability of cellular membranes through an innovative method combining a proton-sensing transistor and a cytosolic LDH leakage assay, which allows us to distinguish between modes of molecule permeation that may occur during endosomal escape. By testing the commercial reagents lipofectin and in vivo JetPEI under physiological and endosomal pH conditions, we found that both lipid- and polymer-based transfection reagents have pH-dependent pore-forming activity, with the former creating smaller pores than the latter. This versatile approach of assessing carrier-membrane interactions is expected to contribute to the development of next-generation nucleic acid delivery systems.