Permission to enter cell by shape: nanodisk vs nanosphere

Biopolymer-Based Nanomedicine for Cancer Therapy: Opportunities and Challenges

Cancer, as the foremost challenge among human diseases, has plagued medical professionals for many years. While there have been numerous treatment approaches in clinical practice, they often cause additional harm to patients. The emergence of nanotechnology has brought new directions for cancer treatment, which can deliver anticancer drugs specifically to tumor areas. This article first introduces the application scenarios of nanotherapies and treatment strategies of nanomedicine. Then, the noteworthy characteristics exhibited by biopolymer materials were described, which make biopolymers stand out in polymeric nanomedicine delivery. Next, we focus on summarizing the state-of-art studies of five categories of proteins (Albumin, Gelatin, Silk fibroin, Zein, Ferritin), nine varieties of polysaccharides (Chitosan, Starch, Hyaluronic acid, Dextran, cellulose, Fucoidan, Carrageenan, Lignin, Pectin) and liposomes in the field of anticancer drug delivery. Finally, we also provide a summary of the advantages and limitations of these biopolymers, discuss the prevailing impediments to their application, and discuss in detail the prospective research directions. This review not only helps readers understand the current development status of nano anticancer drug delivery systems based on biopolymers, but also is helpful for readers to understand the properties of various biopolymers and find suitable solutions in this field through comparative reading.

Ultrathin Flexible Silica Nanosheets with Surface Chemistry-Modulated Affinity to Mammalian Cells

Flexibility of nanomaterials is challenging but worthy to tune for biomedical applications. Biocompatible silica nanomaterials are under extensive exploration but are rarely observed to exhibit flexibility despite the polymeric nature. Herein, a facile one-step route is reported to ultrathin flexible silica nanosheets (NSs), whose low thickness and high diameter-to-thickness ratio enables folding. Thickness and diameter can be readily tuned to enable controlled flexibility. Mechanism study reveals that beyond the commonly used surfactant, the "uncommon" one bearing two hydrophobic tails play a guiding role in producing sheeted/layered/shelled structures, while addition of ethanol appropriately relieved the strong interfacial tension of the assembled surfactants, which will otherwise produce large curled sheeted structures. With these ultrathin NSs, it is further shown that the cellular preference for particle shape and rigidity is highly dependent on surface chemistry of nanoparticles: under high particle-cell affinity, NSs, and especially the flexible ones will be preferred by mammalian cells for internalization or attachment, while this preference is basically invalid when the affinity is low. Therefore, properties of the ultrathin silica NSs can be effectively expanded and empowered by surface chemistry to realize improved bio-sensing or drug delivery.

Beyond the promise: Exploring the complex interactions of nanoparticles within biological systems

The exploration of nanoparticle applications is filled with promise, but their impact on the environment and human health raises growing concerns. These tiny environmental particles can enter the human body through various routes, such as the respiratory system, digestive tract, skin absorption, intravenous injection, and implantation. Once inside, they can travel to distant organs via the bloodstream and lymphatic system. This journey often results in nanoparticles adhering to cell surfaces and being internalized. Upon entering cells, nanoparticles can provoke significant structural and functional changes. They can potentially disrupt critical cellular processes, including damaging cell membranes and cytoskeletons, impairing mitochondrial function, altering nuclear structures, and inhibiting ion channels. These disruptions can lead to widespread alterations by interfering with complex cellular signaling pathways, potentially causing cellular, organ, and systemic impairments. This article delves into the factors influencing how nanoparticles behave in biological systems. These factors include the nanoparticles' size, shape, charge, and chemical composition, as well as the characteristics of the cells and their surrounding environment. It also provides an overview of the impact of nanoparticles on cells, organs, and physiological systems and discusses possible mechanisms behind these adverse effects. Understanding the toxic effects of nanoparticles on physiological systems is crucial for developing safer, more effective nanoparticle-based technologies.

Self-Assembly of Rod-Coil Bottlebrush Copolymers into Degradable Nanodiscs with a UV-Triggered Self-Immolation Process

Polymer nanodiscs, especially with stimuli-responsive features, represent an unexplored frontier in the nanomaterial landscape. Such 2D nanomaterials are considered highly promising for advanced biomedicine applications. Herein, we designed a rod-coil copolymer architecture based on an amphiphilic, tadpole-like bottlebrush copolymer, which can directly self-assemble into core-shell nanodiscs in an aqueous environment. As the bottlebrush side chains are made of amorphous, UV-responsive poly(ethyl glyoxylate) (PEtG) chains, they can undergo rapid end-to-end self-immolation upon light irradiation. This triggered nanodisc disassembly can be used to boost small molecule release from the nanodisc core, which is further aided by a morphological change from discs to spheres.

Nanoscale polymer discs, toroids and platelets: a survey of their syntheses and potential applications

Polymer self-assembly has become a reliable and versatile workhorse to produce polymeric nanomaterials. With appropriate polymer design and monomer selection, polymers can assemble into shapes and morphologies beyond well-studied spherical and cylindrical micellar structures. Steadfast access to anisotropic polymer nanoparticles has meant that the fabrication and application of 2D soft matter has received increasing attention in recent years. In this review, we focus on nanoscale polymer discs, toroids, and platelets: three morphologies that are often interrelated and made from similar starting materials or common intermediates. For each morphology, we illustrate design rules, and group and discuss commonly used self-assembly strategies. We further highlight polymer compositions, fundamental principles and self-assembly conditions that enable precision in bottom-up fabrication strategies. Finally, we summarise potential applications of such nanomaterials, especially in the context of biomedical research and template chemistry and elaborate on future endeavours in this space.

Enhanced Sensitivity of A549 Cells to Doxorubicin with WS2 and WSe2 Nanosheets via the Induction of Autophagy

The excellent physicochemical properties of two-dimensional transition-metal dichalcogenides (2D TMDCs) such as WS2 and WSe2 provide potential benefits for biomedical applications, such as drug delivery, photothermal therapy, and bioimaging. WS2 and WSe2 have recently been used as chemosensitizers; however, the detailed molecular basis underlying WS2- and WSe2-induced sensitization remains elusive. Our recent findings showed that 2D TMDCs with different thicknesses and different element compositions induced autophagy in normal human bronchial epithelial cells and mouse alveolar macrophages at sublethal concentrations. Here, we explored the mechanism by which WS2 and WSe2 act as sensitizers to increase lung cancer cell susceptibility to chemotherapeutic agents. The results showed that WS2 and WSe2 enhanced autophagy flux in A549 lung cancer cells at sublethal concentrations without causing significant cell death. Through the autophagy-specific RT2 Profiler PCR Array, we identified the genes significantly affected by WS2 and WSe2 treatment. Furthermore, the key genes that play central roles in regulating autophagy were identified by constructing a molecular interaction network. A mechanism investigation uncovered that WS2 and WSe2 activated autophagy-related signaling pathways by interacting with different cell surface proteins or cytoplasmic proteins. By utilizing this mechanism, the efficacy of the chemotherapeutic agent doxorubicin was enhanced by WS2 and WSe2 pre-treatment in A549 lung cancer cells. This study revealed a feature of WS2 and WSe2 in cancer therapy, in which they eliminate the resistance of A549 lung cancer cells against doxorubicin, at least partially, by inducing autophagy.

Molecular effects of polystyrene nanoplastics on human neural stem cells

Nanoplastics (NPs) have been found in many ecological environments (aquatic, terrestrial, air). Currently, there is great concern about the exposition and impact on animal health, including humans, because of the effects of ingestion and accumulation of these nanomaterials (NMs) in aquatic organisms and their incorporation into the food chain. NPs´ mechanisms of action on humans are currently unknown. In this study, we evaluated the altered molecular mechanisms on human neural stem cell line (hNS1) after 4 days of exposure to 30 nm polystyrene (PS) NPs (0.5, 2.5 and 10 μg/mL). Our results showed that NPs can induce oxidative stress, cellular stress, DNA damage, alterations in inflammatory response, and apoptosis, which could lead to tissue damage and neurodevelopmental diseases.

The flow of anisotropic nanoparticles in solution and in blood

The alignment of anisotropic nanoparticles in flow has been used for a range of applications such as the preparation of strong fibres and the assembly of in-plane aligned 1D-nanoobjects that are used for electronic devices, sensors, energy and biological application. Important is also the flow behaviour of nanoparticles that were designed for nanomedical applications such as drug delivery. It is widely observed that non-spherical nanoparticles have longer circulation times and a more favourable biodistribution. To be able to understand this behaviour, researchers have turned to analyzing the flow of non-spherical nanoparticles in the blood stream. In this review, an overview of microfluidic techniques that are used to monitor the alignment of anisotropic nanoparticles in solution will be provided, which includes analysis by small angle X-ray scattering (SAXS) and polarized light microscopy. The flow of these nanoparticles in blood is then discussed as the presence of red blood cells causes margination of some nanoparticles. Using fluorescence microscopy, the extent of margination can be identified, which coincides with the ability of nanoparticles to adhere to the cells grown along the wall. While these studies are mainly carried out in vitro using blood, initial investigations in vivo were able to confirm the unusual flow of anisotropic nanoparticles.

How can we use the endocytosis pathways to design nanoparticle drug-delivery vehicles to target cancer cells over healthy cells?

Targeted drug delivery in cancer typically focuses on maximising the endocytosis of drugs into the diseased cells. However, there has been less focus on exploiting the differences in the endocytosis pathways of cancer cells versus non-cancer cells. An understanding of the endocytosis pathways in both cancer and non-cancer cells allows for the design of nanoparticles to deliver drugs to cancer cells whilst restricting healthy cells from taking up anticancer drugs, thus efficiently killing the cancer cells. Herein we compare the differences in the endocytosis pathways of cancer and healthy cells. Second, we highlight the importance of the physicochemical properties of nanoparticles (size, shape, stiffness, and surface chemistry) on cellular uptake and how they can be adjusted to selectively target the dominated endocytosis pathway of cancer cells over healthy cells and to deliver anticancer drug to the target cells. The review generates new thought in the design of cancer-selective nanoparticles based on the endocytosis pathways.

Trends in the Design and Evaluation of Polymeric Nanocarriers: The In Vitro Nano-Bio Interactions

Different types of natural and synthetic polymeric nanocarriers are being tested for diverse biomedical applications ranging from drug/gene delivery vehicles to imaging probes. The development of such innovative nanoparticulate systems (NPs) should include in the very beginning of their conception a comprehensive evaluation of the nano-bio interactions. Specifically, intrinsic physicochemical properties as size, surface charge and shape may have an impact on cellular uptake, intracellular trafficking, exocytosis and cyto- or genocompatibility. Those properties can be tuned for effectiveness purposes such as targeting intracellular organelles, but at the same time inducing unforeseen adverse nanotoxicological effects. Further, those properties may change due to the adsorption of biological components (e.g. proteins) with a tremendous impact on the cellular response. The evaluation of these NPs is highly challenging and has produced some controversial results. Future research work should focus on the standardization of analytical or computational methodologies, aiming the identification of toxicity trends and the generation of a useful meta-analysis database on polymeric nanocarriers.This chapter covers all the aforementioned aspects, emphasizing the importance of the in vitro cellular studies in the first stages of polymeric nanocarriers development.

Polymeric Nanotubes as Drug Delivery Vectors─Comparison of Covalently and Supramolecularly Assembled Constructs

Rod-shaped nanoparticles have been identified as promising drug delivery candidates. In this report, the in vitro cell uptake and in vivo pharmacokinetic/bio-distribution behavior of molecular bottle-brush (BB) and cyclic peptide self-assembled nanotubes were studied in the size range of 36-41 nm in length. It was found that BB possessed the longest plasma circulation time (t_1\2 > 35 h), with the cyclic peptide system displaying an intermediate half-life (14.6 h), although still substantially elevated over a non-assembling linear control (2.7 h). The covalently bound BB underwent substantial distribution into the liver, whereas the cyclic peptide nanotube was able to mostly circumvent organ accumulation, highlighting the advantage of the inherent degradability of the cyclic peptide systems through their reversible aggregation of hydrogen bonding core units.

Polystyrene nanoplastics potentiate the development of hepatic fibrosis in high fat diet fed mice

Polystyrene nanoparticles (PS-NPs) as an issue of global environmental concern, have been shown to induce hepatic toxicity via triggering oxidative injury and inflammation. Non-alcoholic fatty liver disease (NAFLD) is initiated when excessive lipid is accumulated in the liver and will proceed to liver fibrosis with repeatedly chronic liver injury. In this study, we examined whether intravenous injection of PS-NPs could enhance the hepatic toxicity and potentiate the development of liver fibrosis in experimental high fat diet (HFD)-induced mice. The results demonstrated that PS-NPs could aggravate chronic hepatitis by interfere with liver lipid metabolism in HFD induced mice. Further, hepatic tissue in PS-NPs treated HFD mice displayed substantially lowered superoxide dismutase (SOD) activity, which confirming the oxidative stress induced by PS-NPs. PS-NPs exposure also resulted in the up-regulation of inflammation response in liver, as evidenced by the enhanced infiltration of Kupffer cells (KCs) and elevated expression of pro-inflammatory related indicators. Meanwhile, Masson trichrome staining revealed that PS-NPs could aggravate steatohepatitis with higher collagen fiber in HFD fed mice. Our data suggests that PS-NPs can induce oxidative stress and inflammation in HDF-induced experimental mice and further aggravate liver fibrosis, which highlight the potential health risks of PS-NPs.

Spherical and rod shaped mesoporous nanosilicas for cancer-targeted and photosensitizers delivery in photodynamic therapy

Mesoporous silica nanoparticles (MSNPs) have attracted much attention in many biomedical applications. One of the fields in which smart functional nanosystems have found wide application is in cancer treatment. Here,...

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.

Two-dimensional biomaterials: material science, biological effect and biomedical engineering applications

To date, nanotechnology has increasingly been identified as a promising and efficient means to address a number of challenges associated with public health. In the past decade, two-dimensional (2D) biomaterials, as a unique nanoplatform with planar topology, have attracted explosive interest in various fields such as biomedicine due to their unique morphology, physicochemical properties and biological effect. Motivated by the progress of graphene in biomedicine, dozens of types of ultrathin 2D biomaterials have found versatile bio-applications, including biosensing, biomedical imaging, delivery of therapeutic agents, cancer theranostics, tissue engineering, as well as others. The effective utilization of 2D biomaterials stems from the in-depth knowledge of structure-property-bioactivity-biosafety-application-performance relationships. A comprehensive summary of 2D biomaterials for biomedicine is still lacking. In this comprehensive review, we aim to concentrate on the state-of-the-art 2D biomaterials with a particular focus on their versatile biomedical applications. In particular, we discuss the design, fabrication and functionalization of 2D biomaterials used for diverse biomedical applications based on the up-to-date progress. Furthermore, the interactions between 2D biomaterials and biological systems on the spatial-temporal scale are highlighted, which will deepen the understanding of the underlying action mechanism of 2D biomaterials aiding their design with improved functionalities. Finally, taking the bench-to-bedside as a focus, we conclude this review by proposing the current crucial issues/challenges and presenting the future development directions to advance the clinical translation of these emerging 2D biomaterials.

Anisotropic Particles through Multilayer Assembly

The anisotropy in the shape of polymeric particles has been demonstrated to have many advantages over spherical particulates, including bio-mimetic behavior, shaped-directed flow, deformation, surface adhesion, targeting, motion, and permeability. The layer-by-layer (LbL) assembly is uniquely suited for synthesizing anisotropic particles as this method allows for simple and versatile replication of diverse colloid geometries with precise control over their chemical and physical properties. This review highlights recent progress in anisotropic particles of micrometer and nanometer sizes produced by a templated multilayer assembly of synthetic and biological macromolecules. Synthetic approaches to produce capsules and hydrogels utilizing anisotropic templates such as biological, polymeric, bulk hydrogel, inorganic colloids, and metal-organic framework crystals as sacrificial templates are overviewed. Structure-property relationships controlled by the anisotropy in particle shape and surface are discussed and compared with their spherical counterparts. Advances and challenges in controlling particle properties through varying shape anisotropy and surface asymmetry are outlined. The perspective applications of anisotropic colloids in biomedicine, including programmed behavior in the blood and tissues as artificial cells, nano-motors/sensors, and intelligent drug carriers are also discussed.

Solution Self-Assembly of Coil-Crystalline Diblock Copolypeptoids Bearing Alkyl Side Chains

Polypeptoids, a class of synthetic peptidomimetic polymers, have attracted increasing attention due to their potential for biotechnological applications, such as drug/gene delivery, sensing and molecular recognition. Recent investigations on the solution self-assembly of amphiphilic block copolypeptoids highlighted their capability to form a variety of nanostructures with tailorable morphologies and functionalities. Here, we review our recent findings on the solutions self-assembly of coil-crystalline diblock copolypeptoids bearing alkyl side chains. We highlight the solution self-assembly pathways of these polypeptoid block copolymers and show how molecular packing and crystallization of these building blocks affect the self-assembly behavior, resulting in one-dimensional (1D), two-dimensional (2D) and multidimensional hierarchical polymeric nanostructures in solution.

Role of the interactions of soft hyaluronan nanomaterials with CD44 and supported bilayer membranes in the cellular uptake

Increasing valence by acting on nanomaterial morphology can enhance the ability of a ligand to specifically bind to targeted cells. Herein, we investigated cell internalization of soft hyaluronic acid (HA) nanoplatelets (NPs) that exhibit a typical hexagonal shape, flat surfaces and high aspect ratio (Γ≈12 to 20), as characterized by atomic force microscopy in hydrated conditions. Fluorescence imaging revealed that internalization of HA-NPs by a T24 tumor cell line and by macrophages was higher than native polysaccharide in a dose-dependent and time-dependent manners. The ability of HA-NPs to efficiently compete with native HA assessed using Bio-layer interferometry showed that NPs had a stronger interaction with recombinant CD44 receptor compared to native HA. The results were discussed regarding physical properties of the NPs and the implication of multivalent interactions in HA binding to CD44. Experiments conducted on supported bilayer membranes with different compositions showed that non-specific interactions of NPs with lipid membranes were negligible. Our findings provide insights into intracellular drug delivery using soft HA-NPs through receptor-mediated multivalent interactions.

Modulating the Molecular Geometry and Solution Self-Assembly of Amphiphilic Polypeptoid Block Copolymers by Side Chain Branching Pattern

Solution self-assembly of coil-crystalline diblock copolypeptoids has attracted increasing attention due to its capability to form hierarchical nanostructures with tailorable morphologies and functionalities. While the N-substituent (or side chain) structures are known to affect the crystallization of polypeptoids, their roles in dictating the hierarchical solution self-assembly of diblock copolypeptoids are not fully understood. Herein, we designed and synthesized two types of diblock copolypeptoids, i.e., poly(N-methylglycine)-b-poly(N-octylglycine) (PNMG-b-PNOG) and poly(N-methylglycine)-b-poly(N-2-ethyl-1-hexylglycine) (PNMG-b-PNEHG), to investigate the influence of N-substituent structure on the crystalline packing and hierarchical self-assembly of diblock copolypeptoids in methanol. With a linear aliphatic N-substituent, the PNOG blocks pack into a highly ordered crystalline structure with a board-like molecular geometry, resulting in the self-assembly of PNMG-b-PNOG molecules into a hierarchical microflower morphology composed of radially arranged nanoribbon subunits. By contrast, the PNEHG blocks bearing bulky branched aliphatic N-substituents are rod-like and prefer to stack into a columnar hexagonal liquid crystalline mesophase, which drives PNMG-b-PNEHG molecules to self-assemble into symmetrical hexagonal nanosheets in solution. A combination of time-dependent small/wide-angle X-ray scattering and microscopic imaging analysis further revealed the self-assembly mechanisms for the formation of these microflowers and hexagonal nanosheets. These results highlight the significant impact of the N-substituent architecture (i.e., linear versus branched) on the supramolecular self-assembly of diblock copolypeptoids in solution, which can serve as an effective strategy to tune the geometry and hierarchical structure of polypeptoid-based nanomaterials.

The Role of Nanomaterials in Stroke Treatment: Targeting Oxidative Stress

Stroke has a high rate of morbidity and disability, which seriously endangers human health. In stroke, oxidative stress leads to further damage to the brain tissue. Therefore, treatment for oxidative stress is urgently needed. However, antioxidative drugs have demonstrated obvious protective effects in preclinical studies, but the clinical studies have not seen breakthroughs. Nanomaterials, with their characteristically small size, can be used to deliver drugs and have demonstrated excellent performance in treating various diseases. Additionally, some nanomaterials have shown potential in scavenging reactive oxygen species (ROS) in stroke according to the nature of nanomaterials. The drugs' delivery ability of nanomaterials has great significance for the clinical translation and application of antioxidants. It increases drug blood concentration and half-life and targets the ischemic brain to protect cells from oxidative stress-induced death. This review summarizes the characteristics and progress of nanomaterials in the application of antioxidant therapy in stroke, including ischemic stroke, hemorrhagic stroke, and neural regeneration. We also discuss the prospect of nanomaterials for the treatment of oxidative stress in stroke and the challenges in their application, such as the toxicity and the off-target effects of nanomaterials.

Supramolecular cancer nanotheranostics

Among the many challenges in medicine, the treatment and cure of cancer remains an outstanding goal given the complexity and diversity of the disease. Nanotheranostics, the integration of therapy and diagnosis in nanoformulations, is the next generation of personalized medicine to meet the challenges in precise cancer diagnosis, rational management and effective therapy, aiming to significantly increase the survival rate and improve the life quality of cancer patients. Different from most conventional platforms with unsatisfactory theranostic capabilities, supramolecular cancer nanotheranostics have unparalleled advantages in early-stage diagnosis and personal therapy, showing promising potential in clinical translations and applications. In this review, we summarize the progress of supramolecular cancer nanotheranostics and provide guidance for designing new targeted supramolecular theranostic agents. Based on extensive state-of-the-art research, our review will provide the existing and new researchers a foundation from which to advance supramolecular cancer nanotheranostics and promote translationally clinical applications.

Revisiting the cellular toxicity of benzo[a]pyrene from the view of nanoclusters: size- and nanoplastic adsorption-dependent bioavailability

Benzo[a]pyrene (Bap) is one of the main organic pollutants in the atmospheric haze that is rich in fine water drops and particulate matters. The understanding of the Bap's form in water is of great importance to unveil its real biological effects toward the respiratory system. To date, various reports have documented its toxicological effects in the molecular form. Herein, we found that Bap existed as self-aggregated nanoclusters of tunable sizes rather than as dissolved molecules in water and different sized nanoclusters illustrated varied cytotoxicity. These findings indicated that the size, which has been ignored in previous studies, is also a dominant parameter similar to the molecular concentration for determining Bap's cytotoxicity. Polystyrene (PS) nanoparticles, as a model for nanoplastics, could adsorb Bap nanoclusters and serve as carriers that enter the cells. The combination effect interestingly altered the cytotoxicity distinction of Bap of different sizes. The intracellular fate of the nanoparticles and subcellular organelle damages were studied to unveil the mechanisms of cytotoxic distinction. Small Bap nanoclusters entered cells faster than their large counterparts. The Bap of the PS@Bap complex was stably adsorbed on PS at the early stages of endocytosis until it was detached during the lysosomal transport and maturation process. The dissociated Bap may bypass the lysosome pathway and be released into the cytosol with a nanocluster structure or relocate into the endoplasmic reticulum. On the other hand, the detached PS preferred to bind to the mitochondria or be excreted out of the cell via the lysosomal pathway. Moreover, the PS@Bap complex resulted in a significant loss of the mitochondrial membrane potential and induced apoptosis through the mitochondria-involved apoptosis pathway. This study provides a new perspective towards the toxicological mechanism of insoluble hydrophobic organic compounds and reveals the environmental significance of nanoplastics for regulating the biological effects of conventional pollutants.

Responsive Nanostructured Polymer Particles

Responsive polymer particles with switchable properties are of great importance for designing smart materials in various applications. Recently, the self-assembly of block copolymers (BCPs) and polymer blends within evaporative emulsions has led to advances in the shape-controlled synthesis of polymer particles. Despite extensive recent progress on BCP particles, the responsive shape tuning of BCP particles and their applications have received little attention. This review provides a brief overview of recent approaches to developing non-spherical polymer particles from soft evaporative emulsions based on the physical principles affecting both particle shape and inner structure. Special attention is paid to the stimuli-responsive, shape-changing nanostructured polymer particles, i.e., design of polymers and surfactant pairs, detailed experimental results, and their applications, including the state-of-the-art progress in this field. Finally, the perspectives on current challenges and future directions in this research field are presented, including the development of surfactants with higher reversibility to multiple stimuli and polymers with unique structural functionality, and diversification of polymer architectures.

Mechanistic Understanding From Molecular Dynamics Simulation in Pharmaceutical Research 1: Drug Delivery

In this review, we outline the growing role that molecular dynamics simulation is able to play as a design tool in drug delivery. We cover both the pharmaceutical and computational backgrounds, in a pedagogical fashion, as this review is designed to be equally accessible to pharmaceutical researchers interested in what this new computational tool is capable of and experts in molecular modeling who wish to pursue pharmaceutical applications as a context for their research. The field has become too broad for us to concisely describe all work that has been carried out; many comprehensive reviews on subtopics of this area are cited. We discuss the insight molecular dynamics modeling has provided in dissolution and solubility, however, the majority of the discussion is focused on nanomedicine: the development of nanoscale drug delivery vehicles. Here we focus on three areas where molecular dynamics modeling has had a particularly strong impact: (1) behavior in the bloodstream and protective polymer corona, (2) Drug loading and controlled release, and (3) Nanoparticle interaction with both model and biological membranes. We conclude with some thoughts on the role that molecular dynamics simulation can grow to play in the development of new drug delivery systems.

Bilayer-Templated Two-Dimensional RAFT Polymerization for Directed Assembly of Polymer Nanostructures

Co-localization of monomers, crosslinkers, and chain-transfer agents (CTA) within self-assembled bilayers in an aqueous suspension enabled the successful directed assembly of nanocapsules using a reversible addition-fragmentation chain transfer (RAFT) process without compromising the polymerization kinetics. This study uncovered substantial influence of the organized medium on the course of the reaction, including differential reactivity based on placement and mobility of monomers, crosslinkers, and CTAs within the bilayer.

Folate-induced nanostructural changes of oligochitosan nanoparticles and their fate of cellular internalization by melanoma

This study examined the effects of folate environment of oligochitosan nanoparticles on their cellular internalization profiles in human melanoma cells. The conjugates and nanoparticles of oligochitosan-folate, oligochitosan-carboxymethyl-5-fluorouracil, and oligochitosan-folate-carboxymethyl-5-fluorouracil were synthesized by carbodiimide chemistry and prepared by nanospray drying technique respectively. The cellular internalization profiles of oligochitosan-folate nanoparticles against the human malignant melanoma cell line (SKMEL-28) were evaluated using confocal scanning electron microscopy technique through fluorescence labelling and endocytic inhibition, as a function of nanoparticulate folate content, size, polydispersity index, zeta potential, shape, surface roughness and folate population density. The cytotoxicity and cell cycle arrest characteristics of oligochitosan-folate-carboxymethyl-5-fluorouracil nanoparticles, prepared with an optimal folate content that promoted cellular internalization, were evaluated against the oligochitosan-folate and oligochitosan-carboxymethyl-5-fluorouracil conjugate nanoparticles. The oligochitosan-folate conjugate nanoparticles were endocytosed by melanoma cells via caveolae- and lipid raft-mediated endocytic pathways following them binding to the cell surface folate receptor. Nanoparticles that were larger and with higher folic acid contents and zeta potentials exhibited a higher degree of cellular internalization. Excessive conjugation of nanoparticles with folate resulted in a high nanoparticulate density of folate which hindered nanoparticles-cell interaction via folate receptor binding and reduced cellular internalization of nanoparticles. Conjugating oligochitosan with 20 %w/w folate was favorable for cellular uptake as supported by in silico models. Conjugating of oligochitosan nanoparticles with carboxymethyl-5-fluorouracil and 20 %w/w of folate promoted nanoparticles-folate receptor binding, cellular internalization and cancer cell death via cell cycle arrest at S phase at a lower drug dose than oligochitosan-carboxymethyl-5-fluorouracil conjugate nanoparticles and neat carboxymethyl-5-fluorouracil.

Why synthetic virus-like nanoparticles can achieve higher cellular uptake efficiency?

Experimental studies in recent years have demonstrated that the cellular uptake properties of nanoparticles can be improved by mimicking the spiky surfaces of viruses; however, little is known on how the surface topological structure of nanoparticles affects their translocation across the cell membrane. Here, by employing dissipative particle dynamics simulations, the interactions between virus-like nanoparticles (VLPs) and the lipid bilayer are investigated. The analysis of critical force for penetration demonstrates that VLPs with relatively longer and sparser spikes have better penetrability. The internalization pathway of VLPs illustrates that the spikes of VLPs can perturb the bilayer structure after VLPs adhere onto the bilayer. Furthermore, by comparing the translocation process of VLPs and spherical nanoparticles, it is found that the presence of spikes can help to increase the lateral defects in the bilayer, decrease the vertical deformation of the bilayer, and lower the density of nearby lipids during the translocation process. These effects of spikes jointly contribute to the superior penetrability of VLPs. It is expected that these findings not only enrich our understanding of how the surface topological structure affects the cellular uptake, but also pave the way for further development of VLPs for versatile biomedical applications.

The Rational Design and Biological Mechanisms of Nanoradiosensitizers

Radiotherapy (RT) has been widely used for cancer treatment. However, the intrinsic drawbacks of RT, such as radiotoxicity in normal tissues and tumor radioresistance, promoted the development of radiosensitizers. To date, various kinds of nanoparticles have been found to act as radiosensitizers in cancer radiotherapy. This review focuses on the current state of nanoradiosensitizers, especially the related biological mechanisms, and the key design strategies for generating nanoradiosensitizers. The regulation of oxidative stress, DNA damage, the cell cycle, autophagy and apoptosis by nanoradiosensitizers in vitro and in vivo is highlighted, which may guide the rational design of therapeutics for tumor radiosensitization.

Advances in mathematical models of the active targeting of tumor cells by functional nanoparticles

BACKGROUND AND OBJECTIVE

The process of nanoparticles (NPs) entering blood circulation to actively target tumor cells involves four stages-the transport of NPs in blood vessels, transvascular transport of NPs, transport of NPs in the tumor interstitial matrix and entry of NPs into tumor cells. These four stages are a complex process involving mechanical, physical, biochemical, and biophysical factors, the tumor microenvironment (TME) and properties of NPs play important roles in this process. Because this process involves a large number of factors and is very complex, it is difficult to study with conventional methods.

METHODS

Using mathematical models for simulation is suitable for addressing this complex situation and can describe the complexity well.

RESULTS

This work focuses on the theoretical simulation of NPs that target tumor cells to illustrate the effects of the abnormal microenvironment of tumors and properties of NPs on the transport process. Mathematical models constructed by different methods are enumerated. Through studying these mathematical models, different methods to overcome nanoparticle (NP) transport obstacles are illustrated.

CONCLUSIONS

It is necessary to construct a theoretical model of active targeting nanodrug delivery under the coupling of micro-flow field and specific binding force field, and to simulate and analyze the delivery process at mesoscopic scale using computational fluid dynamics (CFD) method, so as to reveal the law and characteristics of drug delivery and cell uptake in the micro-environment of tumors in vivo. The methods and techniques discussed can serve as the basis for systematic studies of active targeting of functional nanoparticles to tumor cells.

Synthesis, thermoresponsivity and multi-tunable hierarchical self-assembly of multi-responsive (AB)mC miktobrush-coil terpolymers

Stimuli-responsive miktobrush-coil terpolymers can exhibit unique physical properties and hierarchical self-assembly behaviors dependent on composition, concentration and external stimuli.

Effect of elasticity on the phagocytosis of micro/nanoparticles

A broad range of investigation methods and frameworks are used to better study the elasticity of various micro/nanoparticles (MNPs) with different properties and to explore the effect of such properties on their interactions with biological species.

Internalization and toxicity: A preliminary study of effects of nanoplastic particles on human lung epithelial cell

As a kind of newly emerging pollutant, nanoplastics are easily to be ingested by organisms, and cause severe damage to biological functions because of their small size, high specific surface area, and strong biological penetration. Recently, there are increasing reports of numerous airborne microplastics, including polystyrene (PS), being detected in atmospheric samples, which implies a potential risk to the human respiratory system. In this work, we evaluated the effects of polystyrene nanoparticles of two different sizes (PS-NP25: 25 nm diameter and PS-NP70: 70 nm diameter) on the human alveolar epithelial A549 cell line including internalization, cell viability, cell cycle, apoptosis, and associated gene transcription and protein expression. Results showed that PS-NP25 was internalized more rapidly and efficiently into the cytoplasm of A549 than PS-NP70. PS-NPs significantly affected the cell viability, caused cell cycle S phrase arrest, activated inflammatory gene transcription, and changed the expression of proteins associated with cell cycle and pro-apoptosis. PS-NPs induced significant up-regulation of pro-inflammatory cytokines such as IL-8, NF-κB, and TNF-α, as well as pro-apoptotic proteins such as DR5, caspase-3, caspase-8, caspase-9, and cytochrome c, which revealed that PS-NPs triggered a TNF-α-associated apoptosis pathway. This study suggests that exposure duration, diameter, and concentration are the key factors for evaluating the toxicological effects of PS-NPs on alveolar epithelial cells. More attention must be focused on the risk of nanoplastic-related air pollution and the environmental toxicological effects of nanoplastics on humans and other terrestrial mammals.

Direct Drug Targeting into Intracellular Compartments: Issues, Limitations, and Future Outlook

Intracellular compartment drug delivery is a promising strategy for the treatment of diseases. By this way, medicines can delivered to particular intracellular compartments. This maximizes the therapeutic efficacy and safety of medicines, particularly of anticancer and antiviral drugs. Intracellular compartment drug delivery is either indirectly by targeting of cell nucleus as central compartment of the cell or directly through the targeting of compartments itself. Drugs or nanoshuttles labeled with compartment's localization signal represent a smart tactic for subcellular compartment targeting. There are several boundaries prevent the arrival of shuttles to the specified intracellular compartments. These boundaries include selective permeability of biomembranes, efflux transporters, and lysosomes. The utilization of specific ligands during design of drug delivery nanoshuttles permits the targeting of specified intracellular compartment. Therefore drugs targeting could correct the diseases associated organelles. This review highlights the direct targeting of the medicines into subcellular compartment as a promising therapeutic strategy.

Entry modes of ellipsoidal nanoparticles on a membrane during clathrin-mediated endocytosis

The membrane wrapping and internalization of nanoparticles, such as viruses and drug nanocarriers, through clathrin-mediated endocytosis (CME) are vitally important for intracellular transport. During CME, the shape of the particle plays crucial roles in the determination of particle-membrane interactions, but much of the previous work has been focused on spherical particles. In this work, we develop a stochastic model to study the CME of ellipsoidal particles. In our model, the deformation of the membrane and wrapping of the nanoparticles are driven by the accumulation of clathrin lattices, which is stimulated by the ligand-receptor interactions. Using our model, we systematically investigate the effect of particle shape (ellipsoids with different aspect ratios) on the CME. Our results show three entry modes: tip-first, tilted, and laying-down modes, used by ellipsoidal nanoparticles for internalization depending on the aspect ratio. Certain ellipsoids are able to take multiple entry modes for internalization. Interestingly, the prolate ellipsoid with an aspect ratio of 0.42 can be internalized with a significantly reduced number of ligand-receptor bonds. Particles which can be internalized with fewer bonds are excellent candidates for transcellular drug delivery. Moreover, our results demonstrate that internalization of ellipsoids with intermediate aspect ratios is easier than that of particles with low and high aspect ratios. Our model and simulations provide critical mechanistic insights into CME of ellipsoidal particles, and represent a viable platform for optimal design of nanoparticles for targeted drug delivery applications.

Induction of mTOR-dependent autophagy by WS2 nanosheets from both inside and outside of human cells

The applications of two-dimensional transition metal dichalcogenides (2D TMDCs) pose an increased risk to both the environment and human health. Due to the large surface area of 2D nanosheets, they often form multi-layered nanoclusters of various thicknesses in aqueous solution. In this work, we address the safety issue of 2D TMDCs with focus on the cellular effects of the thickness of WS2 nanosheets. At a very low and non-lethal concentration (4 cm2 mL-1 or 25 μg mL-1), 4-layered WS2 nanosheets (WS2-4) were primarily bound to the cell surface with less internalization, while 30-layered WS2 nanosheets (WS2-30) were mostly internalized by human bronchial epithelial cells. Although the cellular interactions at this low concentration caused no alterations in the cell cycle, apoptosis, necrosis and cytotoxicity, cell autophagy was induced in both cases through mTOR-dependent pathways by perturbing a number of signaling molecules, such as amyloid precursor protein (APP) and cysteine-X-cysteine chemokine receptor 4 (CXCR-4). The finding of activation of cell autophagy from both outside and inside of cells reveals a novel feature of biological perturbations by 2D nanosheets. This finding will help in the formulation of general guidelines for the safe application of 2D nanomaterials.

Role of Surface Chemistry in Mediating the Uptake of Ultrasmall Iron Oxide Nanoparticles by Cancer Cells

Ultrasmall iron oxide nanoparticles (USIONPs) (<4 nm) have recently attracted significant attention because of their potential as positive T₁ magnetic resonance imaging (MRI) contrast agent contrary to larger superparamagnetic iron oxide nanoparticles (>6 nm) which act as negative T₂ MRI contrast agents. However, studies on the cellular uptake behavior of these nanoparticles are very limited compared to their counterpart, larger-sized superparamagnetic iron oxide nanoparticles. In particular, the effects of specific nanoparticle parameters on the cellular uptake behavior of USIONPs by various cancer cells are not available. Here, we specifically investigated the role of USIONPs' surface functionalities [tannic acid (TA) and quinic acid (QA)] in mediating cellular uptake behavior of cancer cells pertaining to primary (U87 cells) and metastatic (MDA-MB-231Br cells) brain malignancies. Here, we chose TA and QA as representative capping molecules, wherein TA coating provides a general negatively charged nontargeting surface while QA provides a tumor-targeting surface as QA and its derivatives are known to interact with selectin receptors expressed on tumor cells and tumor endothelium. We observed differential cellular uptake in the case of TA- and QA-coated USIONPs by cancer cells. Both the cell types showed significantly higher cellular uptake of QA-coated USIONPs compared to TA-coated USIONPs at 4, 24, and 72 h. Blocking studies indicated that P-selectin cell surface receptors, in part, mediated the cellular uptake of QA-coated USIONPs. Given that P-selectin is overexpressed in cancer cells, tumor microenvironment, and at the metastatic niche, QA-coated USIONPs hold potential to be utilized as a platform for tumor-targeted drug delivery and in imaging and detection of primary and metastatic tumors.

Shape and Color Switchable Block Copolymer Particles by Temperature and pH Dual Responses

Herein, we report a simple and robust strategy for preparing dual-responsive shape-switchable block copolymer (BCP) particles, which respond to subtle temperature and pH changes near physiological conditions (i.e., human body temperature and neutral pH). The shape transition of polystyrene- b-poly(4-vinylpyridine) BCP particles between lens and football shapes occurs in very narrow temperature and pH ranges: no temperature-based transition for pH 6.0, 40-50 °C transition for pH 6.5, and 25-35 °C for pH 7.0. To achieve these shape transitions, temperature/pH-responsive polymer surfactants of poly( N-(2-(diethylamino)ethyl)acrylamide- r- N-isopropylacrylamide) are designed to induce dramatic changes in relative solubility and their location in response to temperature and pH changes near physiological conditions. In addition, the BCP particles exhibit reversible shape-transforming behavior according to orthogonal temperature and pH changes. Colorimetric measurements of temperature and pH changes are enabled by shape-transforming properties combined with selective positioning of dyes, suggesting promising potential for these particles in clinical and biomedical applications.

Remote Induction of Cell Autophagy by 2D MoS2 Nanosheets via Perturbing Cell Surface Receptors and mTOR Pathway from Outside of Cells

The ability of nanoparticles to induce adverse consequences in human cells relies on their physical shapes. In this aspect, how two-dimensional nanoparticles differ from three-dimensional nanoparticles is not well-known. To elucidate this difference, combined experimental and theoretical approaches are employed to compare MoS₂ nanosheets with 5-layer and 40-layer thicknesses for their cellular effects and the associated molecular events. At a concentration as defined by the nanosheet surface areas (10 cm²/mL), 40-layer nanosheets are internalized by cells, whereas 5-layer nanosheets mostly bind to the cell surface without internalization. Although they alter different autophagy-related genes, a common mechanism is that they both perturb cell surface protein amyloid precursor proteins and activate the mTOR signaling pathway. Our findings prove that the perturbation of cellular function without nanoparticle internalization has significant nanomedicinal and nanotoxicological significances.

Membrane Wrapping Efficiency of Elastic Nanoparticles during Endocytosis: Size and Shape Matter

Using coarse-grained molecular dynamics simulations, we systematically investigate the receptor-mediated endocytosis of elastic nanoparticles (NPs) with different sizes, ranging from 25 to 100 nm, and shapes, including sphere-like, oblate-like, and prolate-like. Simulation results provide clear evidence that the membrane wrapping efficiency of NPs during endocytosis is a result of competition between receptor diffusion kinetics and thermodynamic driving force. The receptor diffusion kinetics refer to the kinetics of receptor recruitment that are affected by the contact edge length between the NP and membrane. The thermodynamic driving force represents the amount of required free energy to drive NPs into a cell. Under the volume constraint of elastic NPs, the soft spherical NPs are found to have similar contact edge lengths to rigid ones and to less efficiently be fully wrapped due to their elastic deformation. Moreover, the difference in wrapping efficiency between soft and rigid spherical NPs increases with their sizes, due to the increment of their elastic energy change. Furthermore, because of its prominent large contact edge length, the oblate ellipsoid is found to be the least sensitive geometry to the variation in NP's elasticity among the spherical, prolate, and oblate shapes during the membrane wrapping. In addition, simulation results indicate that conflicting experimental observations on the efficiency of cellular uptake of elastic NPs could be caused by their different mechanical properties. Our simulations provide a detailed mechanistic understanding about the influence of NPs' size, shape, and elasticity on their membrane wrapping efficiency, which serves as a rational guidance for the design of NP-based drug carriers.

Building Functional Nanodevices with Vesicle-Templated Porous Polymer Nanocapsules

Vesicle-templated nanocapsules offer a unique combination of properties enabled by robust shells with single-nanometer thickness containing programmed uniform pores capable of fast and selective mass transfer. These capsules emerged as a versatile platform for creating functional devices, such as nanoreactors, nanosensors, and containers for the delivery of drugs and imaging agents. Nanocapsules are synthesized by a directed assembly method using self-assembled bilayers of vesicles as temporary scaffolds. In this approach, hydrophobic building blocks are loaded into the hydrophobic interior of vesicles formed from lipids or surfactants. Pore-forming templates are codissolved with the monomers and cross-linkers in the interior of the bilayer. The polymerization forms a cross-linked shell with embedded pore-forming templates. Removal of the surfactant scaffold and pore-forming templates leads to free-standing nanocapsules with shells containing uniform imprinted nanopores. Development of reliable and scalable synthetic methods for the modular construction of capsules with tunable properties has opened the opportunity to pursue practical applications of nanocapsules. In this Account, we discuss how unique properties of vesicle-templated nanocapsules translate into the creation of functional nanodevices. Specifically, we focus the conversation on applications aiming at the delivery of drugs and imaging agents, creation of fast-acting and selective nanoreactors, and fabrication of nanoprobes for sensing and imaging. We present a brief overview of the synthesis of nanocapsules with an emphasis on recent developments leading to robust synthetic methods including the synthesis under physiological conditions and creation of biodegradable nanocapsules. We then highlight unique properties of nanocapsules essential for practical applications, such as precise control of pore size and chemical environment, selective permeability, and ultrafast transport through the pores. We discuss new motifs for catch and release of small molecules with porous nanocapsules based on controlling the microenvironment inside the nanocapsules, regulating the charge on the orifice of nanopores in the shells, and reversible synergistic action of host and guest forming a supramolecular complex in nanocapsules. We demonstrate successful creation of fast-acting and selective nanoreactors by encapsulation of diverse homogeneous and nanoparticle catalysts. Due to unhindered flow of substrates and products through the nanopores, encapsulation did not compromise catalytic efficiency and, in fact, improved the stability of entrapped catalysts. We present robust nanoprobes based on nanocapsules with entrapped sensing agents and show how the encapsulation resulted in selective measurements with fast response times in challenging conditions, such as small volumes and complex mixtures. Throughout this Account, we highlight the advantages of encapsulation and discuss the opportunities for future design of nanodevices.

Doxorubicin and indocyanine green loaded superparamagnetic iron oxide nanoparticles with PEGylated phospholipid coating for magnetic resonance with fluorescence imaging and chemotherapy of glioma

Background

Glioma represents the most common malignant brain tumor. Outcomes of surgical resection are often unsatisfactory due to low sensitivity or resolution of imaging methods. Moreover, the use of traditional chemotherapeutics, such as doxorubicin (DOX), is limited due to their low blood-brain barrier (BBB) permeability. Recently, the development of nanotechnology could overcome these obstacles.

Materials and methods

Hydrophobic superparamagnetic iron oxide nanoparticles (SPIO NPs) were prepared with the use of thermal decomposition method. They were coated with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG 2000) and DOX using a thin-film hydration method followed by loading of indocyanine green (ICG) into the phospholipid layers. Details regarding the characteristics of NPs were determined. The in vitro biocompatibility and antitumor efficacy were established with the use of MTT assay. In vivo fluorescence and magnetic resonance (MR) imaging were used to evaluate BBB penetration and accumulation of NPs at the tumor site. Antitumor efficacy was evaluated using measures of tumor size, median survival times, body weights, and H&E staining.

Results

The multifunctional NPs generated had an average diameter of 22.9 nm, a zeta potential of -38.19 mV, and were capable of providing a sustained release of DOX. In vitro experiments demonstrated that the SPIO@DSPE-PEG/DOX/ICG NPs effectively enhanced cellular uptake of DOX as compared with that of free DOX. In vivo fluorescence and MR imaging revealed that the NPs not only effectively crossed the BBB but selectively accumulated at the tumor site. Meanwhile, among all groups studied, C6 glioma-bearing rats treated with the NPs exhibited the maximal degree of therapeutic efficacy, including smallest tumor volume, lowest body weight loss, and longest survival times, with no obvious side effects.

Conclusion

These results suggest that the SPIO@DSPE-PEG/DOX/ICG NPs can not only function as a nanoprobe for MR and fluorescence bimodal imaging, but also as a vehicle to deliver chemotherapeutic drugs to the tumor site, to achieve the theranostic treatment of glioma.

Morphological and mechanical determinants of cellular uptake of deformable nanoparticles

Understanding the interactions of nanoparticles (NPs) with cell membranes and regulating their cellular uptake processes are of fundamental importance to the design of drug delivery systems with minimum toxicity, high efficiency and long circulation time. Employing the procedure of coarse-graining, we built an elastically deformable NP model with tunable morphological and mechanical properties. We found that the cellular uptake of deformable NPs depends on their shape: an increase in the particle elasticity significantly slows the uptake rate of spherical NPs, slightly retards that of prolate NPs, and promotes the uptake of oblate NPs. The intrinsic mechanisms have been carefully investigated through analysis of the endocytic mechanisms and free energy calculations. These findings provide unique insights into how deformable NPs penetrate across cell membranes and offer novel possibilities for designing effective NP-based carriers for drug delivery.

Self-assembled, ellipsoidal polymeric nanoparticles for intracellular delivery of therapeutics

Nanoparticle shape has emerged as a key regulator of nanoparticle transport across physiological barriers, intracellular uptake, and biodistribution. We report a facile approach to synthesize ellipsoidal nanoparticles through self-assembly of poly(glycerol sebacate)-co-poly(ethylene glycol) (PGS-co-PEG). The PGS-PEG nanoparticle system is highly tunable, and the semiaxis length of the nanoparticles can be modulated by changing PGS-PEG molar ratio and incorporating therapeutics. As both PGS and PEG are highly biocompatible, the PGS-co-PEG nanoparticles show high hemo-, immuno-, and cytocompatibility. Our data suggest that PGS-co-PEG nanoparticles have the potential for use in a wide range of biomedical applications including regenerative medicine, stem cell engineering, immune modulation, and cancer therapeutics. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2048-2058, 2018.

Near-Infrared-Light-Activatable Nanomaterial-Mediated Phototheranostic Nanomedicines: An Emerging Paradigm for Cancer Treatment

Cancer is one of the most deadly diseases threatening the lives of humans. Although many treatment methods have been developed to tackle cancer, each modality of cancer treatment has its own limitations and drawbacks. The development of minimally invasive treatment modalities for cancers remains a great challenge. Near-infrared (NIR) light-activated nanomaterial-mediated phototherapies, including photothermal and photodynamic therapies, provide an alternative means for spatially and temporally controlled minimally invasive treatments of cancers. Nanomaterials can serve as nanocargoes for the delivery of chemo-drugs, diagnostic contrast reagents, and organic photosensitizers, and can be used to directly generate heat or reactive oxygen species for the treatment of tumors without the need for organic photosensitizers with NIR-light irradiation. Here, current progress in NIR-light-activated nanomaterial-mediated photothermal therapy and photodynamic therapy is summarized. Furthermore, the effects of size, shape, and surface functionalities of nanomaterials on intracellular uptake, macrophage clearance, biodistribution, cytotoxicities, and biomedical efficacies are discussed. The use of various types of nanomaterials, such as gold nanoparticles, carbon nanotubes, graphene, and many other inorganic nanostructures, in combination with diagnostic and therapeutic modalities for solid tumors, is briefly reviewed.