Unambiguous observation of shape effects on cellular fate of nanoparticles

Effects of nanoparticle size, shape, and zeta potential on drug delivery

Nanotechnology has brought about a significant revolution in drug delivery, and research in this domain is increasingly focusing on understanding the role of nanoparticle (NP) characteristics in drug delivery efficiency. First and foremost, we center our attention on the size of nanoparticles. Studies have indicated that NP size significantly influences factors such as circulation time, targeting capabilities, and cellular uptake. Secondly, we examine the significance of nanoparticle shape. Various studies suggest that NPs of different shapes affect cellular uptake mechanisms and offer potential advantages in directing drug delivery. For instance, cylindrical or needle-like NPs may facilitate better cellular uptake compared to spherical NPs. Lastly, we address the importance of nanoparticle charge. Zeta potential can impact the targeting and cellular uptake of NPs. Positively charged NPs may be better absorbed by negatively charged cells, whereas negatively charged NPs might perform more effectively in positively charged cells. This review provides essential insights into understanding the role of nanoparticles in drug delivery. The properties of nanoparticles, including size, shape, and charge, should be taken into consideration in the rational design of drug delivery systems, as optimizing these characteristics can contribute to more efficient targeting of drugs to the desired tissues. Thus, research into nanoparticle properties will continue to play a crucial role in the future of drug delivery.

Exploring the effect of hydroxyapatite nanoparticle shape on red blood cells and blood coagulation

Aim: In this study, we evaluated the effects of two types of hydroxyapatite (HAP) nanoparticles, sharing the same surface chemistry but differing in shape, on the biological characteristics of plasma, platelets and red blood cells.Materials & methods: Initially, two different shapes (rod-shaped and sphere-shaped) of HAPs were characterized. These HAPs were then co-cultured with plasma and red blood cells to examine their impact on coagulation and hemolysis. The impact of HAPs on white blood cells count in mice were evaluated following gavage and tail vein injection.Results: Sphere-shaped HAP is more likely to adsorb onto platelet surfaces, while rod-shaped HAP is more likely to cause hemolysis. Although there are differences in the in vitro experimental results between sphere-shaped HAP and rod-shaped HAP, both types demonstrate good blood compatibility at a 20 mM concentration. Furthermore, in vivo experiments showed that sphere-shaped nano-HAP induced a more pronounced increase in white blood cell count, suggesting that it may exhibit greater toxicity.Conclusion: While differences exist in the blood compatibility test results between the two HAPs, these differences are minimal, with both results falling within a safe range. Overall, HAP demonstrates excellent blood compatibility.

Differential Impact of Zinc Salt Precursors on Physiognomies, Anticancerous, and Antibacterial Activities of Zinc Oxide Nanoparticles

Zinc oxide nanoparticles (ZnONPs) are enormously popular semi-conductor metal oxides with diverse applications in every field of science. Many physical and chemical methods applied for the synthesis of ZnONPs are being rejected due to their environmental hazards. Therefore, ZnONPs synthesized from plant extracts are steered as eco-friendly showing more biocompatibility and biodegradability. Additionally, various synthesis conditions such as the type of precursor salt also play a role in influencing the physicochemical and biological properties of ZnONPs. In this study, green synthesis of ZnONPs from Acacia nilotica was carried out using zinc acetate (ZA-AN-ZNPs), zinc nitrate (ZN-AN-ZNPs), and zinc sulfate (ZS-AN-ZNPs) precursor salts. Surprisingly, characterization of ZnONPs using UV-visible spectroscopy, TEM, XRD, and EDX revealed the important role precursor salts played in influencing the size and shape of ZnONPs, i.e., 20-23 nm spherical (ZA-AN-ZNPs), 55-59 nm triangular (ZN-AN-ZNPs), and 94-97 nm nano-flowers (ZS-AN-ZNPs). FTIR analysis showed the involvement of alkaloids, alcohols, carboxylic acid, and phenolic compounds present in Acacia nilotica extract during the synthesis process. Since different precursor salts showed different morphology of ZnONPs, their biological activities were also variable. ZN-AN-ZNPs showed the highest cytotoxicity towards HepG2 cells with the lowest cell viability (28.92 ± 0.99%), highest ROS/RNS production (3425.3 ± 184.58 relative DHR123 fluorescence), and loss of mitochondrial membrane potential (1645.2 ± 32.12 relative fluorescence unit) as well as induced significant caspase-3 gene expression. In addition to this, studying the zone of inhibitions and minimum bactericidal and inhibitory concentrations of ZnONPs showed their exceptional potential as antibacterial agents. At MIC as low as 8 µg/mL, ZA-AN-ZNPs and ZN-AN-ZNPs exhibited significant bactericidal activities against human pathogens Klebsiella pneumoniae and Listeria monocytogenes, respectively. Furthermore, alkaline phosphatase, DNA/RNA leakage, and phosphate ion leakage studies revealed that a damage to the bacterial cell membrane and cell wall is involved in mediating the antibacterial effects of ZnONPs.

Virus-Shaped Mesoporous Silica Nanostars to Improve the Transport of Drugs across the Blood-Brain Barrier

Conditions affecting the brain are the second leading cause of death globally. One of the main challenges for drugs targeting brain diseases is passing the blood-brain barrier (BBB). Here, the effectiveness of mesoporous silica nanostars (MSiNSs) with two different spike lengths to cross an in vitro BBB multicellular model was evaluated and compared to spherical nanoparticles (MSiNP). A modified sol-gel single-micelle epitaxial growth was used to produce MSiNS, which showed no cytotoxicity or immunogenicity at concentrations of up to 1 μg mL-1 in peripheral blood mononuclear and neuronal cells. The nanostar MSiNS effectively penetrated the BBB model after 24 h, and MSiNS-1 with a shorter spike length (9 ± 2 nm) crossed the in vitro BBB model more rapidly than the MSiNS-2 with longer spikes (18 ± 4 nm) or spherical MSiNP at 96 h, which accumulated in the apical and basolateral sides, respectively. Molecular dynamic simulations illustrated an increase in configurational flexibility of the lipid bilayer during contact with the MSiNS, resulting in wrapping, whereas the MSiNP suppressed membrane fluctuations. This work advances an effective brain drug delivery system based on virus-like shaped MSiNS for the treatment of different brain diseases and a mechanism for their interaction with lipid bilayers.

Recent advances in gene delivery nanoplatforms based on spherical nucleic acids

Gene therapy is a therapeutic option for mitigating diseases that do not respond well to pharmacological therapy. This type of therapy allows for correcting altered and defective genes by transferring nucleic acids to target cells. Notably, achieving a desirable outcome is possible by successfully delivering genetic materials into the cell. In-vivo gene transfer strategies use two major classes of vectors, namely viral and nonviral. Both of these systems have distinct pros and cons, and the choice of a delivery system depends on therapeutic objectives and other considerations. Safe and efficient gene transfer is the main feature of any delivery system. Spherical nucleic acids (SNAs) are nanotechnology-based gene delivery systems (i.e., non-viral vectors). They are three-dimensional structures consisting of a hollow or solid spherical core nanoparticle that is functionalized with a dense and highly organized layer of oligonucleotides. The unique structural features of SNAs confer them a high potency in internalization into various types of tissue and cells, a high stability against nucleases, and efficay in penetrating through various biological barriers (such as the skin, blood-brain barrier, and blood-tumor barrier). SNAs also show negligible toxicity and trigger minimal immune response reactions. During the last two decades, all these favorable physicochemical and biological attributes have made them attractive vehicles for drug and nucleic acid delivery. This article discusses the unique structural properties, types of SNAs, and also optimization mechanisms of SNAs. We also focus on recent advances in the synthesis of gene delivery nanoplatforms based on the SNAs.

Role of ESCCAL-1 in regulating exocytosis of AuNPs in human esophageal squamous carcinoma cells

Exocytosis is a critical factor for designing efficient nanocarriers and determining cytotoxicity. However, the research on the exocytosis mechanism of nanoparticles, especially the role of long non-coding RNAs (lncRNAs), has not been reported. In this study, the exocytosis of AuNPs in the KYSE70 cells and the involved molecular pathways of exocytosis are analyzed. It demonstrates that nanoparticles underwent time-dependent release from the cells by exocytosis, and the release of β-hexosaminidase confirms that AuNPs are excreted through lysosomes. Mechanistic studies reveal that lncRNA ESCCAL-1 plays a vital role in controlling the exocytosis of AuNPs through activation of the MAPK pathway, including the phosphorylation of ERK and JNK. The study implies that the ESCCAL-1-mediated pathway plays an important role in the exocytosis of AuNPs in KYSE70 cells. This finding has implications for the role of ESCCAL-1 on the drug resistance of esophagus cancer by controlling lysosome-mediated exocytosis.

Single Extracellular Vesicle Imaging and Computational Analysis Identifies Inherent Architectural Heterogeneity

Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM), which has an inherent ability to image biological samples without harsh labeling methods while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources, such as cancer cells, normal cells, immortalized cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366 ± 0.2, and the average equivalent diameter was 132.43 ± 67 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical, rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution images of EVs and offer insights into their potential biological impact.

Nanodiamonds: Next generation nano-theranostics for cancer therapy

Cancer remains a leading global cause of mortality, demanding early diagnosis and effective treatment. Traditional therapeutic methods often fall short due to their need for more specificity and systemic toxicity. In this challenging landscape, nanodiamonds (ND) emerge as a potential solution, mitigating the limitations of conventional approaches. ND are tiny carbon particles that mimic traditional diamonds chemical stability and hardness and harness nanomaterials' advantages. ND stands out for the unique properties that make them promising nanotheranostics candidates, combining therapeutic and imaging capabilities in one platform. Many of these applications depend on the design of the particle's surface, as the surface's role is crucial in transporting bioactive molecules, preventing aggregation, and building composite materials. This review delves into ND's distinctive features, structural and optical characteristics, and their profound relevance in advancing cancer diagnosis and treatment methods. The report delves into how these exceptional ND properties drive the development of state-of-the-art techniques for precise tumor targeting, boosting the effectiveness of chemotherapy as a chemosensitizer, harnessing immunotherapy strategies, facilitating precision medicine, and creating localized microfilm devices for targeted therapies.

Cell-particles interaction - selective uptake and transport of microdiamonds

Diamond particles have recently emerged as novel agents in cellular studies because of their superb biocompatibility. Their unique characteristics, including small size and the presence of fluorescent color centers, stimulate many important applications. However, the mechanism of interaction between cells and diamond particles-uptake, transport, and final localization within cells-is not yet fully understood. Herein, we show a novel, to the best of our knowledge, cell behavior wherein cells actively target and uptake diamond particles rather than latex beads from their surroundings, followed by their active transport within cells. Furthermore, we demonstrate that myosin-X is involved in cell-particle interaction, while myosin-II does not participate in particle uptake and transport. These results can have important implications for drug delivery and improve sensing methods that use diamond particles.

The use of a complex tetra-culture alveolar model to study the biological effects induced by gold nanoparticles with different physicochemical properties

A substantial increase in engineered nanoparticles in consumer products has been observed, heightening human and environmental exposure. Inhalation represents the primary route of human exposure, necessitating a focus on lung toxicity studies. However, to avoid ethical concerns the use of in vitro models is an efficient alternative to in vivo models. This study utilized an in vitro human alveolar barrier model at air-liquid-interface with four cell lines, for evaluating the biological effects of different gold nanoparticles. Exposure to PEGylated gold nanospheres, nanorods, and nanostars did not significantly impact viability after 24 h, yet all AuNPs induced cytotoxicity in the form of membrane integrity impairment. Gold quantification revealed cellular uptake and transport. Transcriptomic analysis identified gene expression changes, particularly related to the enhancement of immune cells. Despite limited impact, distinct effects were observed, emphasizing the influence of nanoparticles physicochemical parameters while demonstrating the model's efficacy in investigating particle biological effects.

Cellular uptake and fate of cationic polymer-coated nanodiamonds delivering siRNA: a mechanistic study

Gene silencing using small interfering RNAs (siRNAs) is a selective and promising approach for treatment of numerous diseases. However, broad applications of siRNAs are compromised by their low stability in a biological environment and limited ability to penetrate cells. Nanodiamonds (NDs) coated with cationic polymers can enable cellular delivery of siRNAs. Recently, we developed a new type of ND coating based on a random copolymer consisting of (2-dimethylaminoethyl) methacrylate (DMAEMA) and N-(2-hydroxypropyl) methacrylamide (HPMA) monomers. These hybrid ND-polymer particles (Cop+-FND) provide near-infrared fluorescence, form stable complexes with siRNA in serum, show low toxicity, and effectively deliver siRNA into cells in vitro and in vivo. Here, we present data on the mechanism of cellular uptake and cell trafficking of Cop+-FND : siRNA complexes and their ability to selectively suppress mRNA levels, as well as their cytotoxicity, viability and colloidal stability. We identified clathrin-mediated endocytosis as the predominant entry mechanism for Cop+-FND : siRNA into U-2 OS human bone osteosarcoma cells, with a substantial fraction of Cop+-FND : siRNA following the lysosome pathway. Cop+-FND : siRNA potently inhibited the target GAPDH gene with negligible toxicity and sufficient colloidal stability. Based on our results, we suggest that Cop+-FND : siRNA can serve as a suitable in vivo delivery system for siRNA.

Shape Dependent Therapeutic Potential of Nanoparticulate System: Advance Approach for Drug Delivery

Drug delivery systems rely heavily on nanoparticles because they provide a targeted and monitored release of pharmaceuticals that maximize therapeutic efficacy and minimize side effects. To maximize drug internalization, this review focuses on comprehending the interactions between biological systems and nanoparticles. The way that nanoparticles behave during cellular uptake, distribution, and retention in the body is determined by their shape. Different forms, such as mesoporous silica nanoparticles, micelles, and nanorods, each have special properties that influence how well drugs are delivered to cells and internalized. To achieve the desired particle morphology, shape-controlled nanoparticle synthesis strategies take into account variables like pH, temperatures, and reaction time. Top-down techniques entail dissolving bulk materials to produce nanoparticles, whereas bottom-up techniques enable nanostructures to self-assemble. Comprehending the interactions at the bio-nano interface is essential to surmounting biological barriers and enhancing the therapeutic efficacy of nanotechnology in drug delivery systems. In general, drug internalization and distribution are greatly influenced by the shape of nanoparticles, which presents an opportunity for tailored and efficient treatment plans in a range of medical applications.

Quantum Diamonds at the Beach: Chemical Insights into Silica Growth on Nanoscale Diamond using Multimodal Characterization and Simulation

Surface chemistry of materials that host quantum bits such as diamond is an important avenue of exploration as quantum computation and quantum sensing platforms mature. Interfacing diamond in general and nanoscale diamond (ND) in particular with silica is a potential route to integrate room temperature quantum bits into photonic devices, fiber optics, cells, or tissues with flexible functionalization chemistry. While silica growth on ND cores has been used successfully for quantum sensing and biolabeling, the surface mechanism to initiate growth was unknown. This report describes the surface chemistry responsible for silica bond formation on diamond and uses X-ray absorption spectroscopy (XAS) to probe the diamond surface chemistry and its electronic structure with increasing silica thickness. A modified Stöber (Cigler) method was used to synthesize 2-35 nm thick shells of SiO2 onto carboxylic acid-rich ND cores. The diamond morphology, surface, and electronic structure were characterized by overlapping techniques including electron microscopy. Importantly, we discovered that SiO2 growth on carboxylated NDs eliminates the presence of carboxylic acids and that basic ethanolic solutions convert the ND surface to an alcohol-rich surface prior to silica growth. The data supports a mechanism that alcohols on the ND surface generate silyl-ether (ND-O-Si-(OH)3) bonds due to rehydroxylation by ammonium hydroxide in ethanol. The suppression of the diamond electronic structure as a function of SiO2 thickness was observed for the first time, and a maximum probing depth of ∼14 nm was calculated. XAS spectra based on the Auger electron escape depth was modeled using the NIST database for the Simulation of Electron Spectra for Surface Analysis (SESSA) to support our experimental results. Additionally, resonant inelastic X-ray scattering (RIXS) maps produced by the transition edge sensor reinforces the chemical analysis provided by XAS. Researchers using diamond or high-pressure high temperature (HPHT) NDs and other exotic materials (e.g., silicon carbide or cubic-boron nitride) for quantum sensing applications may exploit these results to design new layered or core-shell quantum sensors by forming covalent bonds via surface alcohol groups.

Prospects and hazards of silica nanoparticles: Biological impacts and implicated mechanisms

With the thrive of nanotechnology, silica nanoparticles (SiNPs) have been extensively adopted in the agriculture, food, cosmetic, and even biomedical industries. Due to the mass production and use, SiNPs inevitably entered the environment, resulting in ecological toxicity and even posing a threat to human health. Although considerable investigations have been conducted to assess the toxicity of SiNPs, the correlation between SiNPs exposure and consequent health risks remains ambiguous. Since the biological impacts of SiNPs can differ from their design and application, the toxicity assessment for SiNPs may be extremely difficult. This review discussed the application of SiNPs in different fields, especially their biomedical use, and documented their potential release pathways into the environment. Meanwhile, the current process of assessing SiNPs-related toxicity on various model organisms and cell lines was also detailed, thus estimating the health threats posed by SiNPs exposure. Finally, the potential toxic mechanisms of SiNPs were also elaborated based on results obtained from both in vivo and in vitro trials. This review generally summarizes the biological effects of SiNPs, which will build up a comprehensive perspective of the application and toxicity of SiNPs.

Simultaneous Electrophysiology and Imaging Reveal Changes in Lipid Membrane Thickness and Tension upon Uptake of Amphiphilic Gold Nanoparticles

Amphiphilic gold core nanoparticles (AmNPs) striped with hydrophilic 11-mercapto-1-undecanesulfonate (MUS) and hydrophobic 1-octanethiol (OT) ligands are promising candidates for drug carriers that passively and nondisruptively enter cells. Yet, how they interact with cellular membranes is still only partially understood. Herein, we use electrophysiology and imaging to carefully assess changes in droplet interface bilayer lipid membranes (DIBs) incurred by striped AmNPs added via microinjection. We find that AmNPs spontaneously reduce the steady-state specific capacitance and contact angle of phosphatidylcholine DIBs by amounts dependent on the final NP concentration. These reductions, which are greater for NPs with a higher % OT ligands and membranes containing unsaturated lipids but negligible for MUS-only-coated NPs, reveal that AmNPs passively embed in the interior of the bilayer where they increase membrane thickness and lateral tension through disruption of lipid packing. These results demonstrate the enhanced evaluation of nano-bio interactions possible via electrophysiology and imaging of DIBs.

Modification of Tomato Photosystem II Photochemistry with Engineered Zinc Oxide Nanorods

We recently proposed the use of engineered irregularly shaped zinc oxide nanoparticles (ZnO NPs) coated with oleylamine (OAm), as photosynthetic biostimulants, to enhance crop yield. In the current research, we tested newly engineered rod-shaped ZnO nanorods (NRs) coated with oleylamine (ZnO@OAm NRs) regarding their in vivo behavior related to photosynthetic function and reactive oxygen species (ROS) generation in tomato (Lycopersicon esculentum Mill.) plants. ZnO@OAm NRs were produced via solvothermal synthesis. Their physicochemical assessment revealed a crystallite size of 15 nm, an organic coating of 8.7% w/w, a hydrodynamic diameter of 122 nm, and a ζ-potential of -4.8 mV. The chlorophyll content of tomato leaflets after a foliar spray with 15 mg L-1 ZnO@OAm NRs presented a hormetic response, with an increased content 30 min after the spray, which dropped to control levels 90 min after the spray. Simultaneously, 90 min after the spray, the efficiency of the oxygen-evolving complex (OEC) decreased significantly (p < 0.05) compared to control values, with a concomitant increase in ROS generation, a decrease in the maximum efficiency of PSII photochemistry (Fv/Fm), a decrease in the electron transport rate (ETR), and a decrease in the effective quantum yield of PSII photochemistry (ΦPSII), indicating reduced PSII efficiency. The decreased ETR and ΦPSII were due to the reduced efficiency of PSII reaction centers (Fv'/Fm'). There were no alterations in the excess excitation energy at PSII or the fraction of open PSII reaction centers (qp). We discovered that rod-shaped ZnO@OAm NRs reduced PSII photochemistry, in contrast to irregularly shaped ZnO@OAm NPs, which enhanced PSII efficiency. Thus, the shape and organic coating of the nanoparticles play a critical role in the mechanism of their action and their impact on crop yield when they are used in agriculture.

Getting fat and stressed: Effects of dietary intake of titanium dioxide nanoparticles in the liver of turbot Scophthalmus maximus

The extensive use of nanomaterials, including titanium dioxide nanoparticles (TiO2 NPs), raises concerns about their persistence in ecosystems. Protecting aquatic ecosystems and ensuring healthy and safe aquaculture products requires the assessment of the potential impacts of NPs on organisms. Here, we study the effects of a sublethal concentration of citrate-coated TiO2 NPs of two different primary sizes over time in flatfish turbot, Scophthalmus maximus (Linnaeus, 1758). Bioaccumulation, histology and gene expression were assessed in the liver to address morphophysiological responses to citrate-coated TiO2 NPs. Our analyses demonstrated a variable abundance of lipid droplets (LDs) in hepatocytes dependent on TiO2 NPs size, an increase in turbot exposed to smaller TiO2 NPs and a depletion with larger TiO2 NPs. The expression patterns of genes related to oxidative and immune responses and lipid metabolism (nrf2, nfκb1, and cpt1a) were dependent on the presence of TiO2 NPs and time of exposure supporting the variance in hepatic LDs distribution over time with the different NPs. The citrate coating is proposed as the likely catalyst for such effects. Thus, our findings highlight the need to scrutinize the risks associated with exposure to NPs with distinct properties, such as primary size, coatings, and crystalline forms, in aquatic organisms.

Silicon Vacancy in Boron-Doped Nanodiamonds for Optical Temperature Sensing

Boron-doped nanodiamonds (BNDs) have recently shown a promising potential in hyperthermia and thermoablation therapy, especially in heating tumor cells. To remotely monitor eigen temperature during such operations, diamond color centers have shown a sensitive optical temperature sensing. Nitrogen-vacancy (NV) color center in diamonds have shown the best sensitivity in nanothermometry; however, spin manipulation of the NV center with green laser and microwave-frequency excitations is still a huge challenge for biological applications. Silicon-vacancy (SiV) color center in nano/bulk diamonds has shown a great potential to be a good replacement of the NV center in diamond as it can be excited and detected within the biological transparency window and its thermometry operations depends only on its zero-phonon line (ZPL) shift as a function of temperature changes. In this work, BNDs were carefully etched on smooth diamond nanocrystals' sharp edges and implanted with silicon for optical temperature sensing. Optical temperature sensing using SiV color centers in BNDs was performed over a small range of temperature within the biological temperature window (296-308 K) with an excellent sensitivity of 0.2 K in 10 s integration time. These results indicate that there are likely to be better application of more biocompatible BNDs in hyperthermia and thermoablation therapy using a biocompatible diamond color center.

Magnetoelectric nanoparticles shape modulates their electrical output

Core-shell magnetoelectric nanoparticles (MENPs) have recently gained popularity thanks to their capability in inducing a local electric polarization upon an applied magnetic field and vice versa. This work estimates the magnetoelectrical behavior, in terms of magnetoelectric coupling coefficient (αME), via finite element analysis of MENPs with different shapes under either static (DC bias) and time-variant (AC bias) external magnetic fields. With this approach, the dependence of the magnetoelectrical performance on the MENPs geometrical features can be directly derived. Results show that MENPs with a more elongated morphology exhibits a superior αME if compared with spherical nanoparticles of similar volume, under both stimulation conditions analyzed. This response is due to the presence of a larger surface area at the interface between the magnetostrictive core and piezoelectric shell, and to the MENP geometrical orientation along the direction of the magnetic field. These findings pave a new way for the design of novel high-aspect ratio magnetic nanostructures with an improved magnetoelectric behaviour.

Exocytosis of Nanoparticles: A Comprehensive Review

Both biomedical applications and safety assessments of manufactured nanomaterials require a thorough understanding of the interaction between nanomaterials and cells, including how nanomaterials enter cells, transport within cells, and leave cells. However, compared to the extensively studied uptake and trafficking of nanoparticles (NPs) in cells, less attention has been paid to the exocytosis of NPs. Yet exocytosis is an indispensable process of regulating the content of NPs in cells, which in turn influences, even decides, the toxicity of NPs to cells. A comprehensive understanding of the mechanisms and influencing factors of the exocytosis of NPs is not only essential for the safety assessment of NPs but also helpful for guiding the design of safe and highly effective NP-based materials for various purposes. Herein, we review the current status and progress of studies on the exocytosis of NPs. Firstly, we introduce experimental procedures and considerations. Then, exocytosis mechanisms/pathways are summarized with a detailed introduction of the main pathways (lysosomal and endoplasmic reticulum/Golgi pathway) and the role of microtubules; the patterns of exocytosis kinetics are presented and discussed. Subsequently, the influencing factors (initial content and location of intracellular NPs, physiochemical properties of NPs, cell type, and extracellular conditions) are fully discussed. Although there are inconsistent results, some rules are obtained, like smaller and charged NPs are more easily excreted. Finally, the challenges and future directions in the field have been discussed.

Optical and electronic spin properties of fluorescent micro- and nanodiamonds upon prolonged ultrahigh-temperature annealing

High-temperature annealing is a promising but still mainly unexplored method for enhancing spin properties of negatively charged nitrogen-vacancy (NV) centers in diamond particles. After high-energy irradiation, the formation of NV centers in diamond particles is typically accomplished via annealing at temperatures in the range of 800-900 °C for 1-2 h to promote vacancy diffusion. Here, we investigate the effects of conventional annealing (900 °C for 2 h) against annealing at a much higher temperature of 1600 °C for the same annealing duration for particles ranging in size from 100 nm to 15 μm using electron paramagnetic resonance and optical characterization. At this high temperature, the vacancy-assisted diffusion of nitrogen can occur. Previously, the annealing of diamond particles at this temperature was performed over short time scales because of concerns of particle graphitization. Our results demonstrate that particles that survive this prolonged 1600 °C annealing show increased NV T1 and T2 electron spin relaxation times in 1 and 15 μm particles, due to the removal of fast relaxing spins. Additionally, this high-temperature annealing also boosts magnetically induced fluorescence contrast of NV centers for particle sizes ranging from 100 nm to 15 μm. At the same time, the content of NV centers is decreased fewfold and reaches a level of <0.5 ppm. The results provide guidance for future studies and the optimization of high-temperature annealing of fluorescent diamond particles for applications relying on the spin properties of NV centers in the host crystals.

Advanced Strategies for Overcoming Endosomal/Lysosomal Barrier in Nanodrug Delivery

Nanocarriers have therapeutic potential to facilitate drug delivery, including biological agents, small-molecule drugs, and nucleic acids. However, their efficiency is limited by several factors; among which, endosomal/lysosomal degradation after endocytosis is the most important. This review summarizes advanced strategies for overcoming endosomal/lysosomal barriers to efficient nanodrug delivery based on the perspective of cellular uptake and intracellular transport mechanisms. These strategies include promoting endosomal/lysosomal escape, using non-endocytic methods of delivery to directly cross the cell membrane to evade endosomes/lysosomes and making a detour pathway to evade endosomes/lysosomes. On the basis of the findings of this review, we proposed several promising strategies for overcoming endosomal/lysosomal barriers through the smarter and more efficient design of nanodrug delivery systems for future clinical applications.

Nanoparticle Spikes Enhance Cellular Uptake via Regulating Myosin IIA Recruitment

Spike-like nanostructures are omnipresent in natural and artificial systems. Although biorecognition of nanostructures to cellular receptors has been indicated as the primary factor for virus infection pathways, how the spiky morphology of DNA-modified nanoparticles affects their cellular uptake and intracellular fate remains to be explored. Here, we design dually emissive gold nanoparticles with varied spikiness (from 0 to 2) to probe the interactions of spiky nanoparticles with cells. We discovered that nanospikes at the nanoparticle regulated myosin IIA recruitment at the cell membrane during cellular uptake, thereby enhancing cellular uptake efficiency, as revealed by dual-modality (plasmonic and fluorescence) imaging. Furthermore, the spiky nanoparticles also exhibited facilitated endocytosis dynamics, as revealed by real-time dark-field microscopy (DFM) imaging and colorimetry-based classification algorithms. These findings highlight the crucial role of the spiky morphology in regulating the intracellular fate of nanoparticles, which may shed light on engineering theranostic nanocarriers.

Highly Dispersed 3C Silicon Carbide Nanoparticles with a Polydopamine/Polyglycerol Shell for Versatile Functionalization

Silicon carbide (SiC) nanoparticles containing lattice defects are attracting considerable attention as next-generation imaging probes and quantum sensors for visualizing and sensing life activities. However, SiC nanoparticles are not currently used in biomedical applications because of the lack of technology for controlling their physicochemical properties. Therefore, in this study, SiC nanoparticles are deaggregated, surface-coated, functionalized, and selectively labeled to biomolecules of interest. A thermal-oxidation chemical-etching method is developed for deaggregating and producing a high yield of dispersed metal-contaminant-free SiC nanoparticles. We further demonstrated a polydopamine coating with controllable thickness that can be used as a platform for decorating gold nanoparticles on the surface, enabling photothermal application. We also demonstrated a polyglycerol coating, which gives excellent dispersity to SiC nanoparticles. Furthermore, a single-pot method is developed to produce mono/multifunctional polyglycerol-modified SiC nanoparticles. Using this method, CD44 proteins on cell surfaces are selectively labeled through biotin-mediated immunostaining. The methods developed in this study are fundamental for applying SiC nanoparticles to biomedical applications and should considerably accelerate the development of various SiC nanoparticles to exploit their potential applications in bioimaging and biosensing.

Potential lifetime effects caused by cellular uptake of nanoplastics: A review

Plastics have been used for about 100 years, and daily-use products composed of plastics are now prevalent. As a result, humans are very easily exposed to the plastic particles generated from the daily-use plastics. However, studies on cellular uptake of nanoplastics in "human cells" have only recently begun to attract attention. In previous studies, definitions of nanoplastics and microplastics were vague, but recently, they have been considered to be different and are being studied separately. However, nanoplastics, unlike plastic particles of other sizes such as macro- and microplastics, can be absorbed by human cells, and thus can cause various risks such as cytotoxicity, inflammation, oxidative stress, and even diseases such as cancer^{82, 83.} and diabetes (Fan et al., 2022; Wang et al., 2023). Thus, in this review, we defined microplastics and nanoplastics to be different and described the potential risks of nanoplastics to human caused by cellular uptake according to their diverse factors. In addition, during and following plastic product usage a substantial number of fragments of different sizes can be generated, including nanoplastics. Fragmentation of microplastics into nanoplastics may also occur during ingestion and inhalation, which can potentially cause long-term hazards to human health. However, there are still few in vivo studies conducted on the health effect of nanoplastics ingestion and inhalation.

The intracellular fate and transport mechanism of shape, size and rigidity varied nanocarriers for understanding their oral delivery efficiency

Nanocarriers have become an effective strategy to overcome epithelial absorption barriers. During the absorption process, the endocytosis mechanisms, cell internalization pathways, and transport efficiency of nanocarriers are greatly impacted by their physical properties. To understand the relationship between physical properties of nanocarriers and their abilities overcoming multiple absorption barriers, nanocarriers with variable physical properties were prepared via self-assembly of hydrolyzed α-lactalbumin peptide fragments. The impacts of size, shape, and rigidity of nanocarriers on epithelial cells endocytosis mechanisms, internalization pathways, transport efficiency, and bioavailability were studied systematically. The results showed that nanospheres were mainly internalized via clathrin-mediated endocytosis, which was then locked in lysosomes and degraded enzymatically in cytoplasm. While macropinocytosis was the primary pathway of nanotubes and transported to the endoplasmic reticulum and Golgi apparatus, resulting in a high drug concentration and sustained release in cytoplasm. Besides, nanotubes can overcome the multi-drug resistance by inhibiting the P-glycoprotein efflux. Furthermore, nanotubes can open intercellular tight-junctions instantaneously and reversibly, which promotes transport into blood circulation. The aqueous solubility of hydrophobic bioactive mangiferin (Mgf) was improved by nanocarriers. Most importantly, the bioavailability of Mgf was the highest for cross-linked short nanotube (CSNT) which outperformed free Mgf and other formulations by in vivo pharmacokinetic studies. Finally, Mgf-loaded CSNT showed an excellent therapeutic efficiency in vivo for the intervention of streptozotocin-induced diabetes. These results indicate that cross-linked α-lactalbumin nanotubes could be an effective nanocarrier delivery system for improving the epithelium cellular absorption and bioavailability of hydrophobic bioactive compounds.

Antimonene: a tuneable post-graphene material for advanced applications in optoelectronics, catalysis, energy and biomedicine

The post-graphene era is undoubtedly marked by two-dimensional (2D) materials such as quasi-van der Waals antimonene. This emerging material has a fascinating structure, exhibits a pronounced chemical reactivity (in contrast to graphene), possesses outstanding electronic properties and has been postulated for a plethora of applications. However, chemistry and physics of antimonene remain in their infancy, but fortunately recent discoveries have shed light on its unmatched allotropy and rich chemical reactivity offering a myriad of unprecedented possibilities in terms of fundamental studies and applications. Indeed, antimonene can be considered as one of the most appealing post-graphene 2D materials reported to date, since its structure, properties and applications can be chemically engineered from the ground up (both using top-down and bottom-up approaches), offering an unprecedented level of control in the realm of 2D materials. In this review, we provide an in-depth analysis of the recent advances in the synthesis, characterization and applications of antimonene. First, we start with a general introduction to antimonene, and then we focus on its general chemistry, physical properties, characterization and synthetic strategies. We then perform a comprehensive study on the allotropy, the phase transition mechanisms, the oxidation behaviour and chemical functionalization. From a technological point of view, we further discuss the applications recently reported for antimonene in the fields of optoelectronics, catalysis, energy storage, cancer therapy and sensing. Finally, important aspects such as new scalable methodologies or the promising perspectives in biomedicine are discussed, pinpointing antimonene as a cutting-edge material of broad interest for researchers working in chemistry, physics, materials science and biomedicine.

Role of Tunable Gold Nanostructures in Cancer Nanotheranostics: Implications on Synthesis, Toxicity, Clinical Applications and Their Associated Opportunities and Challenges

The existing diagnosis and treatment modalities have major limitations related to their precision and capability to understand several stages of disease development. A superior therapeutic system consists of a multifunctional approach in early diagnosis of the disease with a simultaneous progressive cure, using a precise medical approach towards complex treatment. These challenges can be addressed via nanotheranostics and explore suitable approaches to improve health care. Nanotechnology in combination with theranostics as an unconventional platform paved the way for developing novel strategies and modalities leading to diagnosis and therapy for complex disease conditions, ranging from acute to chronic levels. Among the metal nanoparticles, gold nanoparticles are being widely used for theranostics due to their inherent non-toxic nature and plasmonic properties. The unique optical and chemical properties of plasmonic metal nanoparticles along with theranostics have led to a promising era of plausible early detection of disease conditions, and they enable real-time monitoring with enhanced non-invasive or minimally invasive imaging of several ailments. This review aims to highlight the improvement and advancement brought to nanotheranostics by gold nanoparticles in the past decade. The clinical use of the metal nanoparticles in nanotheranostics is explained, along with the future perspectives on addressing the key applications related to diagnostics and therapeutics, respectively. The scope of gold nanoparticles and their realistic potential to design a sophisticated theranostic system is discussed in detail, along with their implications in clinical advancements which are the needs of the hour. The review concluded with the challenges, opportunities, and implications on translational potential of using gold nanoparticles in nanotheranostics.

Nanomaterials against intracellular bacterial infection: from drug delivery to intrinsic biofunction

Fighting intracellular bacteria with strong antibiotics evading remains a long-standing challenge. Responding to and regulating the infectious microenvironment is crucial for treating intracellular infections. Sophisticated nanomaterials with unique physicochemical properties exhibit great potential for precise drug delivery towards infection sites, along with modulating infectious microenvironment via their instinct bioactivity. In this review, we first identify the key characters and therapeutic targets of intracellular infection microenvironment. Next, we illustrate how the nanomaterials physicochemical properties, such as size, charge, shape and functionalization affect the interaction between nanomaterials, cells and bacteria. We also introduce the recent progress of nanomaterial-based targeted delivery and controlled release of antibiotics in intracellular infection microenvironment. Notably, we highlight the nanomaterials with unique intrinsic properties, such as metal toxicity and enzyme-like activity for the treatment of intracellular bacteria. Finally, we discuss the opportunities and challenges of bioactive nanomaterials in addressing intracellular infections.

Nanoparticles-mediated CRISPR-Cas9 gene therapy in inherited retinal diseases: applications, challenges, and emerging opportunities

Inherited Retinal Diseases (IRDs) are considered one of the leading causes of blindness worldwide. However, the majority of them still lack a safe and effective treatment due to their complexity and genetic heterogeneity. Recently, gene therapy is gaining importance as an efficient strategy to address IRDs which were previously considered incurable. The development of the clustered regularly-interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) system has strongly empowered the field of gene therapy. However, successful gene modifications rely on the efficient delivery of CRISPR-Cas9 components into the complex three-dimensional (3D) architecture of the human retinal tissue. Intriguing findings in the field of nanoparticles (NPs) meet all the criteria required for CRISPR-Cas9 delivery and have made a great contribution toward its therapeutic applications. In addition, exploiting induced pluripotent stem cell (iPSC) technology and in vitro 3D retinal organoids paved the way for prospective clinical trials of the CRISPR-Cas9 system in treating IRDs. This review highlights important advances in NP-based gene therapy, the CRISPR-Cas9 system, and iPSC-derived retinal organoids with a focus on IRDs. Collectively, these studies establish a multidisciplinary approach by integrating nanomedicine and stem cell technologies and demonstrate the utility of retina organoids in developing effective therapies for IRDs.

Intracellular Quantum Sensing of Free-Radical Generation Induced by Acetaminophen (APAP) in the Cytosol, in Mitochondria and the Nucleus of Macrophages

Acetaminophen overdoses cause cell injury in the liver. It is widely accepted that liver toxicity is initiated by the reactive N-acetyl-para-aminophenol (APAP) metabolite N-acetyl-p-benzoquinone imine (NAPQI), which first depletes glutathione and then irreversibly binds to mitochondrial proteins and nuclear DNA. As a consequence, mitochondrial respiration is inhibited, and DNA strands break. NAPQI also promotes the oxidative stress since glutathione is one of the main free-radical scavengers in the cell. However, so far it is unknown where exactly free radicals are generated. In this study, we used relaxometry, a novel technique that allows nanoscale magnetic resonance imaging detection of free radicals. The method is based on fluorescent nanodiamonds, which change their optical properties based on their magnetic surrounding. To achieve subcellular resolution, these nanodiamonds were targeted to cellular locations, that is, the cytoplasm, mitochondria, and the nucleus. Since relaxometry is sensitive to spin noise from radicals, we were able to measure the radical load in these different organelles. For the first time, we measured APAP-induced free-radical production in an organelle-specific manner, which helps predict and better understand cellular toxicity.

Intracellular Relaxometry, Challenges, and Future Directions

Nitrogen vacancy (NV) centers change their optical properties on the basis of their magnetic surroundings. Since optical signals can be detected more sensitively than small magnetic signals, this technique allows unprecedented sensitivity. Recently, NV center-based relaxometry has been used for measurements in living cells with subcellular resolution. The aim of this Outlook is to identify challenges in the field, including controlling the location of sensing particles, limitations in reproducibility, and issues arising from biocompatibility. We further provide an outlook and point to new directions in the field. These include new diamond materials with NV centers, other defects, or even entirely new materials that might replace diamonds. We further discuss new and more challenging samples, such as tissues or even entire organisms, that might be investigated with NV centers. Then, we address future challenges that have to be resolved in order to achieve this goal. Finally, we discuss new quantities that could be measured with NV centers in the future.

Diamond-Based Nanoscale Quantum Relaxometry for Sensing Free Radical Production in Cells

Diamond magnetometry makes use of fluorescent defects in diamonds to convert magnetic resonance signals into fluorescence. Because optical photons can be detected much more sensitively, this technique currently holds several sensitivity world records for room temperature magnetic measurements. It is orders of magnitude more sensitive than conventional magnetic resonance imaging (MRI) for detecting magnetic resonances. Here, the use of diamond magnetometry to detect free radical production in single living cells with nanometer resolution is experimentally demonstrated. This measuring system is first optimized and calibrated with chemicals at known concentrations. These measurements serve as benchmarks for future experiments. While conventional MRI typically has millimeter resolution, measurements are performed on individual cells to detect nitric oxide signaling at the nanoscale, within 10-20 nm from the internalized particles localized with a diffraction limited optical resolution. This level of detail is inaccessible to the state-of-the-art techniques. Nitric oxide is detected and the dynamics of its production and inhibition in the intra- and extracellular environment are followed.

Single-Particle Tracking and Trajectory Analysis of Fluorescent Nanodiamonds in Cell-Free Environment and Live Cells

Diamond magnetometry can provide new insights on the production of free radicals inside live cells due to its high sensitivity and spatial resolution. However, the measurements often lack intracellular context for the recorded signal. In this paper, the possible use of single-particle tracking and trajectory analysis of fluorescent nanodiamonds (FNDs) to bridge that gap is explored. It starts with simulating a set of different possible scenarios of a particle's movement, reflecting different modes of motion, degrees of confinement, as well as shapes and sizes of that confinement. Then, the insights from the analysis of the simulated trajectories are applied to describe the movement of FNDs in glycerol solutions. It is shown that the measurements are in good agreement with the previously reported findings and that trajectory analysis yields meaningful results, when FNDs are tracked in a simple environment. Then the much more complex situation of FNDs moving inside a live cell is focused. The behavior of the particles after different incubation times is analyzed, and the possible intracellular localization of FNDs is deducted from their trajectories. Finally, this approach is combined with long-term magnetometry methods to obtain maps of the spin relaxation dynamics (or T1) in live cells, as FNDs move through the cytosol.

Functionalized Fluorescent Nanodiamonds for Simultaneous Drug Delivery and Quantum Sensing in HeLa Cells

Here, we present multifunctional fluorescent nanodiamonds (FNDs) for simultaneous drug delivery and free radical detection. For this purpose, we modified FNDs containing nitrogen vacancy (NV) centers with a diazoxide derivative. We found that our particles enter cells more easily and are able to deliver this cancer drug into HeLa cells. The particles were characterized by infrared spectroscopy, dynamic light scattering, and secondary electron microscopy. Compared to the free drug, we observe a sustained release over 72 h rather than 12 h for the free drug. Apart from releasing the drug, with these particles, we can measure the drug's effect on free radical generation directly. This has the advantage that the response is measured locally, where the drug is released. These FNDs change their optical properties based on their magnetic surrounding. More specifically, we make use of a technique called relaxometry to detect spin noise from the free radical at the nanoscale with subcellular resolution. We further compared the results from our new technique with a conventional fluorescence assay for the detection of reactive oxygen species. This provides a new method to investigate the relationship between drug release and the response by the cell via radical formation or inhibition.

Nanomaterials for Natural Killer Cell-Based Immunoimaging and Immunotherapies in Cancer

Natural killer (NK) cells are an important component of the tumor immunosurveillance; activated NK cells can recognize and directly lyse tumor cells eliciting a potent antitumor immune response. Due to their intrinsic ability to unleash cytotoxicity against tumor cells, NK cell-based adoptive cell therapies have gained rapid clinical significance, and many clinical trials are ongoing. However, priming and activating NK cells, infiltration of activated NK cells in the immunosuppressive tumor microenvironment, and tracking the infiltrated NK cells in the tumors remain a critical challenge. To address these challenges, NK cells have been successfully interfaced with nanomaterials where the morphology, composition, and surface characteristics of nanoparticles (NPs) were leveraged to enable longitudinal tracking of NK cells in tumors or deliver therapeutics to prime NK cells. Distinct from other published reviews, in this tutorial review, we summarize the recent findings in the past decade where NPs were used to label NK cells for immunoimaging or deliver treatment to activate NK cells and induce long-term immunity against tumors. We discuss the NP properties that are key to surmounting the current challenges in NK cells and the different strategies employed to advance NK cells-based diagnostics and therapeutics. We conclude the review with an outlook on future directions in NP-NK cell hybrid interfaces, and overall clinical impact and patient response to such interfaces that need to be addressed to enable their clinical translation.

Impact of bandgap tuning on ZnS for degradation of environmental pollutants and disinfection

The materials showing multiple applications are appealing for their practical use and industrial production. To realize the suitable property for various applications, we have produced ZnS (sf-ZnS) and metal-doped ZnS nanoflakes (sf-m-ZnS; where m = Cu, Ni, Cd, Bi, or Mn) and correlated their activity with bandgap variation. We obtained all these materials via hexamethyldisilazane (HMDS)-assisted synthetic method without using any surfactants, polymers, or template molecules and characterized them thoroughly using various techniques. Photocatalytic, as well as antibacterial, activities of these materials showed their bifunctional utility. We have demonstrated the effect of doping and consequent extension of absorption band to the visible region and resultant improved photocatalytic activity under sunlight. Thus, the change in bandgap influenced their performance as photocatalysts. Among all materials produced, sf-Cd-ZnS provided superior results as a photocatalyst while degrading two organic pollutants-rhodamine B (RhB) and methylene blue (MB) in water. The antibacterial activity of sf-ZnS and sf-m-ZnS against Gram-positive bacteria, i.e., Staphylococcus aureus (S. aureus), was examined by the zone of inhibition method, wherein sf-Ni-ZnS showed maximum activity. The enhanced activity of these ZnS materials can be attributed to the free surface of nanoparticles without any capping by organic molecules, which provided an intimate interaction of inorganic semiconductor material with organic and biomolecules. Thus, we have demonstrated modification of properties both by bandgap tuning of materials and providing the opportunity for intimate interaction of materials with substrates. The photocatalytic activity and antibacterial action of metal-doped ZnS produced by our method exhibited their potential for environmental remediation, specifically water purification.

Endosomal Escape of Bioactives Deployed via Nanocarriers: Insights Into the Design of Polymeric Micelles

Cytoplasmic delivery of bioactives requires the use of strategies such as active transport, electroporation, or the use of nanocarriers such as polymeric nanoparticles, liposomes, micelles, and dendrimers. It is essential to deliver bioactive molecules in the cytoplasm to achieve targeted effects by enabling organelle targeting. One of the biggest bottlenecks in the successful cytoplasmic delivery of bioactives through nanocarriers is their sequestration in the endosomes that leads to the degradation of drugs by progressing to lysosomes. In this review, we discussed mechanisms by which nanocarriers are endocytosed, the mechanisms of endosomal escape, and more importantly, the strategies that can be and have been employed for their escape from the endosomes are summarized. Like other nanocarriers, polymeric micelles can be designed for endosomal escape, however, a careful control is needed in their design to balance between the possible toxicity and endosomal escape efficiency. Keeping this in view, polyion complex micelles, and polymers that have the ability to escape the endosome, are fully discussed. Finally, we provided some perspectives for designing the polymeric micelles for efficient cytoplasmic delivery of bioactive agents through endosomal escape.

Quantum nanodiamonds for sensing of biological quantities: Angle, temperature, and thermal conductivity

Measuring physical quantities in the nanometric region inside single cells is of great importance for understanding cellular activity. Thus, the development of biocompatible, sensitive, and reliable nanobiosensors is essential for progress in biological research. Diamond nanoparticles containing nitrogen-vacancy centers (NVCs), referred to as fluorescent nanodiamonds (FNDs), have recently emerged as the sensors that show great promise for ultrasensitive nanosensing of physical quantities. FNDs emit stable fluorescence without photobleaching. Additionally, their distinctive magneto-optical properties enable an optical readout of the quantum states of the electron spin in NVC under ambient conditions. These properties enable the quantitative sensing of physical parameters (temperature, magnetic field, electric field, pH, etc.) in the vicinity of an FND; hence, FNDs are often described as “quantum sensors”. In this review, recent advancements in biosensing applications of FNDs are summarized. First, the principles of orientation and temperature sensing using FND quantum sensors are explained. Next, we introduce surface coating techniques indispensable for controlling the physicochemical properties of FNDs. The achievements of practical biological sensing using surface-coated FNDs, including orientation, temperature, and thermal conductivity, are then highlighted. Finally, the advantages, challenges, and perspectives of the quantum sensing of FND are discussed. This review article is an extended version of the Japanese article, In Situ Measurement of Intracellular Thermal Conductivity Using Diamond Nanoparticle, published in SEIBUTSU BUTSURI Vol. 62, p. 122–124 (2022).

Effect of micro- and nanoparticle shape on biological processes

In the drug delivery field, there is beyond doubt that the shape of micro- and nanoparticles (M&NPs) critically affects their biological fate. Herein, following an introduction describing recent technological advances for designing nonspherical M&NPs, we highlight the role of particle shape in cell capture, subcellular distribution, intracellular drug delivery, and cytotoxicity. Then, we discuss theoretical approaches for understanding the effect of particle shape on internalization by the cell membrane. Subsequently, recent advances on shape-dependent behaviors of M&NPs in the systemic circulation are detailed. In particular, the interaction of M&NPs with blood proteins, biodistribution, and circulation under flow conditions are analyzed. Finally, the hurdles and future directions for developing nonspherical M&NPs are underscored.

Silk Nanocarrier Size Optimization for Enhanced Tumor Cell Penetration and Cytotoxicity In Vitro

Silk nanofibers are versatile carriers for hydrophobic and hydrophilic drugs, but fall short in terms of effective delivery to cells, which is essential for therapeutic benefits. Here, the size of silk nanofibers was tuned by ultrasonic treatment to improve the cell penetration features without impacting the structural features. The gradual decrease in silk nanofiber length from 1700 to 40 nm resulted in improved cell uptake. The internalized silk nanofiber carriers evaded lysosomes, which facilitated retention in cancer cells in vitro. The smaller sizes also facilitated enhanced penetration of tumor spheroids for improved delivery in vitro. The cytotoxicity of paclitaxel (PTX)-laden nanocarriers increased when the length of the silk nanocarriers decreased. Both the drug loading capacity and delivery of silk nanocarriers with optimized sizes suggest potential utility in cell treatments.

Evaluation of the Physico-Chemical Properties of Liposomes Assembled from Bioconjugates of Anisic Acid with Phosphatidylcholine

The aim of this work was the evaluation of the physico-chemical properties of a new type of liposomes that are composed of DPPC and bioconjugates of anisic acid with phosphatidylcholine. In particular, the impact of modified anisic acid phospholipids on the thermotropic parameters of liposomes was determined, which is crucial for using them as potential carriers of active substances in cancer therapies. Their properties were determined using three biophysical methods, namely differential scanning calorimetry (DSC), steady-state fluorimetry and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Moreover, temperature studies of liposomes composed of DPPC and bioconjugates of anisic acid with phosphatidylcholine provided information about the phase transition, fluidity regarding chain order, hydration and dynamics. The DSC results show that the main phase transition peak for conjugates of anisic acid with phosphatidylcholine molecules was broadened and shifted to a lower temperature in a concentration- and structure-dependent manner. The ATR-FTIR results and the results of measurements conducted using fluorescent probes located at different regions in the lipid bilayer are in line with DSC. The results show that the new bioconjugates with phosphatidylcholine have a significant impact on the physico-chemical properties of a membrane and cause a decrease in the temperature of the main phase transition. The consequence of this is greater fluidity of the lipid bilayer.