PEGylated nanoparticles for biological and pharmaceutical applications

Voluntary-Opsonization-Enabled Precision Nanomedicines for Inflammation Treatment

Nanomedicines that target specific blood cells represent an emerging strategy to improve drug biodistribution. However, the protein corona usually disrupts nanomedicine targeting to cells and tissues. Herein, instead of exploring synthetic methods to mitigate the impact of the protein corona, its natural interactions with blood cells are leveraged and turn the protein corona into an active ingredient in treating lung inflammation. It is discovered that molecularly engineered liposomes with inverse phosphocholine lipids rapidly enrich complement fragment iC3b by "voluntary opsonization," which triggers neutrophil hijacking through complement receptor 3 phagocytosis. This neutrophil targeting is cell-state dependent as only those activated by acute inflammation display efficient neutrophil reconstruction. The liposome-loaded neutrophils migrate across the alveolar-capillary barrier, accumulate in the inflamed lung parenchyma within hours, and release their payloads to kill the bacteria. This work shows that, in addition to biological cells, the protein corona can be a new platform for active and precision nanomedicine.

Phosphorylcholine-Grafted Molecular Bottlebrush-Doxorubicin Conjugates: High Structural Stability, Long Circulation in Blood, and Efficient Anticancer Activity

Controlling the particle structure of tumor-targeting nanomedicines in vivo remains challenging but must be achieved to control their in vivo fate and functions. Molecular bottlebrushes (MBs), where brush side chains are densely grafted from a main chain, have recently received attention as building blocks of polymer-based prodrugs because their rigid structure would be expected to demonstrate high structural stability in vivo. Here, we synthesized a poly(methacryloyloxyethyl phosphorylcholine) (pMPC)-grafted molecular bottlebrush (PCMB) conjugated with a cancer drug, doxorubicin (DOX), via an acid-cleavable hydrazone bond. A pMPC-based linear polymer (LP) conjugated with DOX was also prepared for comparison. We confirmed the lack of structural transition in the PCMB between before and after conjugation with DOX using small-angle light and X-ray scattering techniques, whereas the structure of LP was significantly influenced by DOX conjugation and transformed from a random-coil structure to a large agglomerate via hydrophobic interactions among DOXs. Although PCMB-DOX and LP-DOX showed comparable tissue permeability, pharmacokinetics, and ability to accumulate in tumor tissues, the antitumor efficacy of PCMB-DOX was better than that of LP-DOX. This was presumably due to the formation of LP-DOX agglomerates. The diffusion of cleaved DOX would be restricted in the hydrophobic core of the agglomerate, resulting in the DOX release at the tumor site being compromised. In contrast to LP-DOX, DOX release from PCMB-DOX was not compromised after accumulation in tumor tissues because it did not form such an agglomerate, resulting in the strong antitumor effect. We have demonstrated the potential of MBs as building blocks of drug carriers and believe that these findings can contribute to the design of polymer-based nanomedicines.

Antifouling Surfaces Enabled by Surface Grafting of Highly Hydrophilic Sulfoxide Polymer Brushes

Antifouling surfaces are important in a broad range of applications. An effective approach to antifouling surfaces is to covalently attach antifouling polymer brushes. This work reports the synthesis of a new class of antifouling polymer brushes based on highly hydrophilic sulfoxide polymers by surface-initiated photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. The sulfoxide polymer brushes are able to effectively reduce nonspecific adsorption of proteins and cells, demonstrating remarkable antifouling properties. Given the outstanding antifouling behavior of the sulfoxide polymers and versatility of surface-initiated PET-RAFT technology, this work presents a useful and general approach to engineering various material surfaces with antifouling properties, for potential biomedical applications in areas such as tissue engineering, medical implants, and regenerative medicine.

Interrelations of Synthesis Method, Polyethylene Glycol Coating, Physico-Chemical Characteristics, and Antimicrobial Activity of Silver Nanoparticles

Silver nanoparticles (AgNPs) have been found to have extensive biomedical and biological applications. They can be synthesised using chemical and biological methods, and coated by polymer to enhance their stability. Hence, the changes in the physico-chemical characteristics of AgNPs must be scrutinised due to their importance for biological activity. The UV-Visible absorption spectra of polyethylene glycol (PEG) -coated AgNPs displayed a distinctive narrow peak compared to uncoated AgNPs. In addition, High-Resolution Transmission Electron Microscopy analysis revealed that the shapes of all AgNPs, were predominantly spherical, triangular, and rod-shaped. Fourier-Transform Infrared Spectroscopy analysis further confirmed the role of PEG molecules in the reduction and stabilisation of the AgNPs. Moreover, dynamic light scattering analysis also revealed that the polydispersity index values of PEG-coated AgNPs were lower than the uncoated AgNPs, implying a more uniform size distribution. Furthermore, the uncoated and PEG-coated biologically synthesised AgNPs demonstrated antagonisms activities towards tested pathogenic bacteria, whereas no antagonism activity was detected for the chemically synthesised AgNPs. Overall, generalisation on the interrelations of synthesis methods, PEG coating, characteristics, and antimicrobial activity of AgNPs were established in this study.

Protein Delivery by Peptide-Based Stealth Liposomes: A Biomolecular Insight into Enzyme Replacement Therapy

Infantile neural ceroid lipofuscinosis (INCL) is a lysosomal storage disorder characterized by mutations in the CLN1 gene that leads to lack of the lysosomal enzyme palmitoyl-protein thioesterase-1 (PPT1), which causes the progressive death of cortical neurons. Enzyme replacement therapy (ERT) is one of the most promising treatments, but its translation toward a clinical use is hampered by the need to deliver the enzyme to the central nervous system and a more detailed understanding of its capability to restore physiologic conditions at the biochemical and protein level, beyond the simple regulation of enzymatic activity. Targeted nanoparticles can promote protein delivery to the central nervous system and affect biological pathways inside cells. Here, we describe an innovative peptide-based stealth nanoparticle that inhibits serum protein adsorption exploiting transferrin-driven internalization to convey the PPT1 enzyme to transferrin receptor-mediated pathways (endocytosis in this work, or transcytosis, in perspective, in vivo). These enzyme-loaded nanoparticles were able to restore stable levels of enzymatic activity in CLN1 patient's fibroblasts, comparable with the free enzyme, demonstrating that delivery after encapsulation in the nanocarrier does not alter uptake or intracellular trafficking. We also investigate, for the first time, dysregulated pathways of proteome and palmitoylome and their alteration upon enzyme delivery. Our nanoparticles were able of halving palmitoylated protein levels restoring conditions similar to the normal cells. From proteomic analysis, we also highlighted the reduction of the different groups of proteins after treatments with the free or encapsulated enzyme. In conclusion, our system is able to deliver the enzyme to a model of CLN1 disease restoring normal conditions in cells. Investigation of molecular details of pathologic state and enzyme-based correction reveals dysregulated pathways with unprecedented details for CLN1. Finally, we unveil for the first time the dysregulation landscape of palmitoylome and proteome in primary patient-derived fibroblasts and their modifications in response to enzyme administration. These findings will provide a guideline for the validation of future therapeutic strategies based on enzyme replacement therapy or acting at different metabolic levels.

Enhanced dispersion stability of gold nanoparticles by the physisorption of cyclic poly(ethylene glycol)

Nano-sized metal particles are attracting much interest in industrial and biomedical applications due to the recent progress and development of nanotechnology, and the surface-modifications by appropriate polymers are key techniques to stably express their characteristics. Herein, we applied cyclic poly(ethylene glycol) (c-PEG), having no chemical inhomogeneity, to provide a polymer topology-dependent stabilization for the surface-modification of gold nanoparticles (AuNPs) through physisorption. By simply mixing c-PEG, but not linear counterparts, enables AuNPs to maintain dispersibility through freezing, lyophilization, or heating. Surprisingly, c-PEG endowed AuNPs with even better dispersion stability than thiolated PEG (HS-PEG-OMe). The stronger affinity of c-PEG was confirmed by DLS, ζ-potential, and FT-IR. Furthermore, the c-PEG system exhibited prolonged blood circulation and enhanced tumor accumulation in mice. Our data suggests that c-PEG induces physisorption on AuNPs, supplying sufficient stability toward bio-medical applications, and would be an alternative approach to the gold-sulfur chemisorption.

Biodegradable Hollow Manganese Silicate Nanocomposites to Alleviate Tumor Hypoxia toward Enhanced Photodynamic Therapy

Photodynamic therapy (PDT) has been extensively explored as a minimally invasive treatment strategy for malignant cancers. It works with the help of a photosensitizer located within cancer cells that is irradiated by near-infrared light to produce potent toxins and singlet oxygen (¹O₂) and induce cell death. However, reactive oxygen species can be overexpressed in tumor tissue because of the rapid metabolic activity in cancer cells, and the insufficient oxygenation (hypoxia) can lead to low production of singlet oxygen (¹O₂) during PDT. In this study, we developed nanocomposites composed of a hollow manganese silicate (HMnOSi) nanoparticle and a photosensitizer (Ce6) that can generate significant amounts of O₂ to relieve tumor hypoxia and enhance the therapeutic efficacy of PDT. Our nanocomposites were characterized by UV-vis, fluorescence spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray, and dynamic light scattering. Our particles' hollow mesoporous structures were shown to retain large amounts of Ce6 on the particle surface with high loading capacity (33%). TEM imaging showed that the nanoparticles could be biodegradable over time in simulated body fluid, which can imply clinical potentials. Significant H₂O₂ quenching capabilities to alleviate hypoxic conditions in a solid tumor were also presented. For breast cancer cells, the nanocomposite-treated group revealed that 91% of cells were dead under laser activation compared to 51% for the control group (free Ce6). In an animal study, our nanocomposites showed almost fourfold tumor growth inhibition versus the control and more than twofold over free Ce6 in orthotopic tumor xenografts. In addition, the oxygen saturation contrast inside tumors was evaluated by photoacoustic imaging to demonstrate the alleviated hypoxia in vivo. Our works provide a smart nanosystem to ameliorate the hypoxic tumor microenvironment and augment the efficacy of PDT in a targeted cancer treatment.

Inorganic-organic core/shell nanoparticles: progress and applications

In recent decades a great deal of research has been dedicated to the development of core-shell nanoparticles (NPs). We decided to focus our attention on NPs with inorganic cores and organic shells and divide them by area of application such as electrical applications, drug delivery, biomedical applications, imaging, chemistry and catalysis. Organic shells, consisting in most cases of polymers (natural or synthetic), proteins or complex sugars, can improve the performance of inorganic NPs by enhancing their biocompatibility, acting as anchor sites for molecular linkages or protecting them from oxidation. Moreover, suitable design of the shell thickness can improve the chemical and thermal stability of NPs together with the possibility of tuning and controlling the release of molecules from the core. In the future new discoveries will guarantee improvement in the properties of NPs, synthesis, and applications of this class of nanomaterials that are constantly evolving.

Liposome-Based Drug Delivery Systems in Cancer Immunotherapy

Cancer immunotherapy has shown remarkable progress in recent years. Nanocarriers, such as liposomes, have favorable advantages with the potential to further improve cancer immunotherapy and even stronger immune responses by improving cell type-specific delivery and enhancing drug efficacy. Liposomes can offer solutions to common problems faced by several cancer immunotherapies, including the following: (1) Vaccination: Liposomes can improve the delivery of antigens and other stimulatory molecules to antigen-presenting cells or T cells; (2) Tumor normalization: Liposomes can deliver drugs selectively to the tumor microenvironment to overcome the immune-suppressive state; (3) Rewiring of tumor signaling: Liposomes can be used for the delivery of specific drugs to specific cell types to correct or modulate pathways to facilitate better anti-tumor immune responses; (4) Combinational therapy: Liposomes are ideal vehicles for the simultaneous delivery of drugs to be combined with other therapies, including chemotherapy, radiotherapy, and phototherapy. In this review, different liposomal systems specifically developed for immunomodulation in cancer are summarized and discussed.

BioPerine Encapsulated Nanoformulation for Overcoming Drug-Resistant Breast Cancers

The evolving dynamics of drug resistance due to tumor heterogeneity often creates impediments to traditional therapies making it a challenging issue for cancer cure. Breast cancer often faces challenges of current therapeutic interventions owing to its multiple complexities and high drug resistivity， for example against drugs like trastuzumab and tamoxifen. Drug resistance in the majority of breast cancer is often aided by the overtly expressed P-glycoprotein (P-gp) that guides in the rapid drug efflux of chemotherapy drugs. Despite continuous endeavors and ground-breaking achievements in the pursuit of finding better cancer therapeutic avenues, drug resistance is still a menace to hold back. Among newer therapeutic approaches, the application of phytonutrients such as alkaloids to suppress P-gp activity in drug-resistant cancers has found an exciting niche in the arena of alternative cancer therapies. In this work, we would like to present a black pepper alkaloid derivative known as BioPerine-loaded chitosan (CS)-polyethylene glycol (PEG) coated polylactic acid (PLA) hybrid polymeric nanoparticle to improve the bioavailability of BioPerine and its therapeutic efficacy in suppressing P-gp expression in MDA-MB 453 breast cancer cell line. Our findings revealed that the CS-PEG-BioPerine-PLA nanoparticles demonstrated a smooth spherical morphology with an average size of 316 nm, with improved aqueous solubility, and provided sustained BioPerine release. The nanoparticles also enhanced in vitro cytotoxicity and downregulation of P-gp expression in MDA-MB 453 cells compared to the commercial inhibitor verapamil hydrochloride, thus promising a piece of exciting evidence for the development of BioPerine based nano-drug delivery system in combination with traditional therapies as a crucial approach to tackling multi-drug resistance in cancers.

Aerosolizable Lipid Nanoparticles for Pulmonary Delivery of mRNA through Design of Experiments

Messenger RNA is a class of promising nucleic acid therapeutics to treat a variety of diseases, including genetic diseases. The development of a stable and efficacious mRNA pulmonary delivery system would enable high therapeutic concentrations locally in the lungs to improve efficacy and limit potential toxicities. In this study, we employed a Design of Experiments (DOE) strategy to screen a library of lipid nanoparticle compositions to identify formulations possessing high potency both before and after aerosolization. Lipid nanoparticles (LNPs) showed stable physicochemical properties for at least 14 days of storage at 4 °C, and most formulations exhibited high encapsulation efficiencies greater than 80%. Generally, upon nebulization, LNP formulations showed increased particle size and decreased encapsulation efficiencies. An increasing molar ratio of poly-(ethylene) glycol (PEG)-lipid significantly decreased size but also intracellular protein expression of mRNA. We identified four formulations possessing higher intracellular protein expression ability in vitro even after aerosolization which were then assessed in in vivo studies. It was found that luciferase protein was predominately expressed in the mouse lung for the four lead formulations before and after nebulization. This study demonstrated that LNPs hold promise to be applied for aerosolization-mediated pulmonary mRNA delivery.

In Vivo Real-Time Pharmaceutical Evaluations of Near-Infrared II Fluorescent Nanomedicine Bound Polyethylene Glycol Ligands for Tumor Photothermal Ablation

Pharmaceutical evaluations of nanomedicines are of great significance for their further launch into industry and clinic. Near-infrared (NIR) fluorescence imaging plays essential roles in preclinical drug development by providing important insights into the biodistributions of drugs in vivo with deep tissue penetration and high spatiotemporal resolution. However, NIR-II fluorescence imaging has rarely been exploited for in vivo real-time pharmaceutical evaluations of nanomedicine. Herein, we developed a highly emissive NIR-II luminophore to establish a versatile nanoplatform to noninvasively monitor the in vivo metabolism of nanomedicines bound various polyethylene glycol (PEG) ligands in a real-time manner. An alternative D-A-D conjugated oligomer (DTTB) was synthesized to achieve NIR-II emission peaked at ∼1050 nm with high fluorescence QYs of 13.4% and a large absorption coefficient. By anchoring with the DTTB molecule, intrinsically fluorescent micelles were fabricated and bound with PEG ligands at various chain lengths. In vivo NIR-II fluorescence and photoacoustic imaging results revealed that an appropriate PEG chain length could effectively contribute to the longer blood circulation and better tumor targeting. In vivo therapeutic experiments also confirmed the optimized nanomedicines have efficient photothermal elimination of tumors and good biosafety. This work offered an alternative highly fluorescent NIR-II material and demonstrated a promising approach for real-time pharmaceutical evaluation of nanomedicine in vivo.

Improving silymarin oral bioavailability using silica-installed redox nanoparticle to suppress inflammatory bowel disease

Chronic inflammatory diseases such as inflammatory bowel diseases (IBD), which are strongly related to the overproduction of reactive oxygen species (ROS), have become more threatening to health. Silymarin is an active compound with the effect of expressing anti-inflammatory activity; however, it exhibits poor bioavailability due to the rapid metabolism and secretion, low permeability across the intestinal epithelial cells, and poor water solubility. In this study, we developed silica-containing redox nanoparticles (siRNP) with 50-60 nm in diameter to improve the bioavailability of silymarin by improving its uptake into the bloodstream and delivery to the targeted tissues of the colon. Silymarin-loaded siRNP (SM@siRNP) significantly increased the antioxidant capacity and anti-inflammatory efficacy in vitro by scavenging 2,2-diphenyl-1-picrylhydrazyl free radical and suppressing nitric oxide and pro-inflammatory cytokines as compared to the other treatments such as free silymarin, siRNP, and silymarin-loaded si-nRNP (the control nanoparticle without ROS scavenging property). Orally administered SM@siRNP significantly improved the bioavailability of silymarin and its retention in the colonic mucosa. The anti-inflammatory effects of SM@siRNP were also investigated in dextran sodium sulfate (DSS)-induced colitis in mice and it was observed that SM@siRNP treatment significantly improved the damage in the colonic mucosa of DSS colitis mice as compared to the other treatments. The results in this study indicate that SM@siRNP is a promising nanomedicine for enhancing the anti-inflammatory activity of silymarin and has a high potential for the treatment of IBD.

High-Fidelity End-Functionalization of Poly(ethylene glycol) Using Stable and Potent Carbamate Linkages

Commercial PEG-amine is of unreliable quality, and conventional PEG functionalization relies on esterification and etherification steps, suffering from incomplete conversion, harsh reaction conditions, and functional-group incompatibility. To solve these challenges, we propose an efficient strategy for PEG functionalization with carbamate linkages. By fine-tuning terminal amine basicity, stable and high-fidelity PEG-amine with carbamate linkage was obtained, as seen from the clean MALDI-TOF MS pattern. The carbamate strategy was further applied to the synthesis of high-fidelity multi-functionalized PEG with varying reactive groups. Compared to with an ester linkage, amphiphilic PEG-PS block copolymers bearing carbamate junction linkage exhibits preferential self-assembly tendency into vesicles. Moreover, nanoparticles of the latter demonstrate higher drug loading efficiency, encapsulation stability against enzymatic hydrolysis, and improved in vivo retention at the tumor region.

Cellular internalization mechanism of novel Raman probes designed for plant cells

Diphenylacetylene derivatives containing different polymeric components, poly(l-lysine) (pLys) or tetra(ethylene glycol) (TEG) were designed as novel Raman imaging probes with high Raman sensitivity and low cytotoxicity in living plant cells. The pLys-conjugated probe is internalized via an endocytosis-dependent pathway, whereas TEG-conjugated probe most likely induces direct penetration into the plant cells.

Diphenyl acetylene derivatives containing various polymeric components have been designed as new Raman imaging probes. These are taken up by plant cells via different pathways, and the internalization of exogenous molecules can be visualized.

Surface-modified polymeric nanoparticles for drug delivery to cancer cells

INTRODUCTION

The utilization of polymeric nanoparticles, as drug payloads, has been extensively prevailed in cancer therapy. However, the precise distribution of these nanocarriers is restrained by various physiological and cellular obstacles. Nanoparticles must avoid nonspecific interactions with healthy cells and in vivo compartments to circumvent these barriers. Since in vivo interactions of nanoparticles are mainly dependent on surface properties of nanoparticles, efficient control on surface constituents is necessary for the determination of nanoparticles' fate in the body.

AREAS COVERED

In this review, the surface-modified polymeric nanoparticles and their utilization in cancer treatment were elaborated. First, the interaction of nanoparticles with numerous in vivo barriers was highlighted. Second, different strategies to overcome these obstacles were described. Third, some inspiring examples of surface-modified nanoparticles were presented. Later, fabrication and characterization methods of surface-modified nanoparticles were discussed. Finally, the applications of these nanoparticles in different routes of treatments were explored.

EXPERT OPINION

Surface modification of anticancer drug-loaded polymeric nanoparticles can enhance the efficacy, selective targeting, and biodistribution of the anticancer drug at the tumor site.

Comparison of the uptake mechanisms of zwitterionic and negatively charged liposomes by HeLa cells

Zwitterionic molecules are used as an alternative to PEGylation to reduce protein adsorption on nanocarriers. Nonetheless, little is known on the effect of zwitterionic modifications on the mechanisms cells use for nanocarrier uptake. In this study, the uptake mechanism of liposomes containing zwitterionic or negatively charged lipids was characterized using pharmacological inhibitors and RNA interference on HeLa cells to block endocytosis. As expected, introducing zwitterionic lipids reduced protein adsorption in serum, as well as uptake efficiency. Blocking clathrin-mediated endocytosis strongly decreased the uptake of the negatively charged liposomes, but not the zwitterionic ones. Additionally, inhibition of macropinocytosis reduced uptake of both liposomes, but blocking actin polymerization had effects only on the negatively charged ones. Overall, the results clearly indicated that the two liposomes were internalized by HeLa cells using different pathways. Thus, introducing zwitterionic lipids affects not only protein adsorption and uptake efficiency, but also the mechanisms of liposome uptake by cells.

Self-Assembled Dual-Targeted Epirubicin-Hybrid Polydopamine Nanoparticles for Combined Chemo-Photothermal Therapy of Triple-Negative Breast Cancer

PURPOSE

Folic acid and cyclic arginylglycylaspartic acid peptides were introduced to the surface of negatively charged lipid-coated hybrid polydopamine-cysteine cores for the delivery of epirubicin (EPI) (E/PCF-NPs). The combined chemo-photothermal therapy using E/PCF-NPs for triple-negative breast cancer was evaluated.

MATERIALS AND METHODS

The temperature elevation and thermal toxicity of nanoparticles were studied. The morphology and properties of E/PCF-NPs were characterized by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Physicochemical properties, including particle size, zeta potential, drug loading, entrapment efficiency (EE%), stability and in vitro release, were determined. The cell viability, reactive oxygen species (ROS) levels, ratios of oxidized nicotinamide adenine dinucleotide to its reduced form (NAD+/NADH), apoptosis assays, and cellular uptake of E/PCF-NPs were determined on 4T1 cells. Pharmacokinetic studies and tissue distributions were performed and detected by an ultra-high performance liquid chromatography/mass spectrometry system. The antitumor effects of E/PCF-NPs under near-infrared (NIR) laser irradiation were also evaluated.

RESULTS

The sphere-like morphology of E/PCF-NPs showed a high EE%, uniform size of 106.7 nm, remarkable stability, and highly improved cytotoxicity under NIR laser, when compared to that of photothermal treatment alone. In vitro release of EPI from E/PCF-NPs was pH sensitive, and a greater response was achieved under NIR laser irradiation. Compared to chemotherapy or photothermal treatment alone, the combined treatment in vitro significantly inhibited the survival rate of 4T1 cells to 17.7%, induced ROS generation, and reduced NAD+/NADH significantly. Treatment with E/PCF-NPs under irradiation induced 4T1 cell apoptosis in approximately 93.6% cells. In vitro cellular uptake of E/PCF-NPs was time-dependent. The long-circulating and higher tumor accumulation of E/PCF-NPs resulted in complete ablation of breast tumor tissue through the enhanced photothermal effect by NIR laser irradiation-mediated cell apoptosis.

CONCLUSION

E/PCF-NPs show enhanced anti-cancer effects due to synergistic effects of chemotherapy with photothermal therapy and may be potential therapeutic agents for cancer treatment.

H2 S-Scavenged and Activated Iron Oxide-Hydroxide Nanospindles for MRI-Guided Photothermal Therapy and Ferroptosis in Colon Cancer

Overproduced hydrogen sulfide (H₂ S) is of vital importance for the progress of colon cancer and promotes cancer cellular proliferation. Devising pharmacological nanomaterials for tumor-specific H₂ S activation will be significant for precise colon cancer treatment. Herein, a biocompatible fusiform iron oxide-hydroxide nanospindles (FeOOH NSs) nanosystem for magnetic resonance imaging (MRI), ferroptosis, and H₂ S based cascade reaction-enhanced combinational colon cancer treatment is developed. The FeOOH NSs can effectively scavenge endogenous H₂ S via the reduction reaction to prohibit the growth of CT26 colon cancer. The cascade produced FeS driven by overexpressed H₂ S exhibits near-infrared-triggered photothermal therapy capability and Fe²⁺ -mediated ferroptosis functionality. Meanwhile, the as-prepared FeOOH NSs can light up tumor tissues as a potent MRI contrast agent. Additionally, FeOOH NSs present desirable biosafety in a murine model for up to three months and avoid any long-term toxicity. Furthermore, it is found that these H₂ S-responsible nanotheranostics do not cause any cure effects on other cancer types, such as 4T1 breast cancer. Overall, the findings illustrate that the biocompatible FeOOH NSs can be successfully employed as a theranostic for specifically treating colon cancer, which may promote the clinical translation and development of H₂ S-responsive nanoplatforms.

Ascorbyl-dipalmitate-stabilised nanoemulsions as a potential localised treatment of inflammatory bowel diseases

Current efforts on inflammatory bowel diseases (IBD) treatment are focused on strategies for localised drug delivery at the intestinal mucosa. Despite the potential of curcumin (CC) for IBD treatment, its low solubility and stability limit its application. Thus, the design of nanocarriers that focus CC delivery at the intestinal epithelium is an area of interest. This work proposes α-tocopherol nanoemulsions (NE) stabilised by ascorbyl-2,6-dipalmitate (ADP) as intestinal CC-carriers. The antioxidant capacity of α-tocopherol and ADP could have a synergistic effect on IBD-affected tissues, characterised by an oxidative environment. We obtained nanoemulsions (NE-ADP) with size below 200 nm, negative surface charge, stable in gastrointestinal media and no toxic in the Caco-2 cell model. Intracellular retention of NE-ADP in Caco-2 cells was observed by confocal microscopy. The extremely low P_app values obtained for CC and α-tocopherol indicated the lack of transport across the Caco-2 monolayer. Control nanoemulsion stabilised by lecithin (NE-L) was greatly transported across the Caco-2 cells monolayer, confirming the relevance of ADP on the cellular retention of NE-ADP. The therapeutic potential of NE-ADP was shown by the significant decrease of intracellular ROS levels. Altogether, these results indicate the potential of NE-ADP as a novel approach for the treatment of IBD.

Mannose-coated polydiacetylene (PDA)-based nanomicelles: synthesis, interaction with concanavalin A and application in the water solubilization and delivery of hydrophobic molecules

Carbohydrate-lectin interactions are involved in a number of relevant biological events including fertilization, immune response, cell adhesion, tumour cell metastasis, and pathogen infection. Lectins are also tissue specific, making carbohydrates not only promising drug candidates but also excellent low molecular weight ligands for active drug delivery system decorations. In order for these interactions to be effective multivalency is essential, as the interaction of a lectin with its cognate monovalent carbohydrate epitope usually takes place with low affinity. Unlike the covalent approach, supramolecular self-assembly of glyco-monomers mediated by non-covalent forces allows accessing multivalent systems with diverse topology, composition, and assembly dynamics in a single step. In order to fine-tune the size and sugar adaptability of spherical micelles at the nanoscale for an optimal glycoside cluster effect, herein we report the synthesis of mannose-coated static micelles from diacetylene-based mannopyranosyl glycolipids differing in the length of the poly(ethyleneglycol) (PEG) chains and the oxidation state of the anomeric sulfur atom. The reported shot-gun like synthetic approach for the synthesis of dilution-insensitive micelles is based on the ability of diacetylenic-based neoglycolipids to self-assemble into micelles in water and to undergo an easy photopolymerization by a simple irradiation at 254 nm. The affinity of the obtained 6 nanosystems was assessed by enzyme-linked lectin assay (ELLA) using the mannose-specific concanavalin A lectin as a model receptor. Relative binding potency enhancements, compared to methyl α-d-mannopyranoside used as control, from 20-, to 29- to 300-fold on a sugar molar basis were observed for micelles derived from sulfonyl-, sulfinyl- and thioglycoside monomers with a tatraethyleneglycol spacer, respectively, indicative of a significant cluster glycoside effect. Moreover, pMic1 micelles are able to solubilize and slowly liberate lipophilic clinically relevant drugs, and show the enhanced cytotoxic effect of docetaxel toward prostate cancer cells. These findings highlight the potential of mannose-coated photopolymerized micelles pMic1 as an efficient nanovector for active delivery of cytotoxic hydrophobic molecules.

Application of advances in endocytosis and membrane trafficking to drug delivery

Multidisciplinary research efforts in the field of drug delivery have led to the development of a variety of drug delivery systems (DDS) designed for site-specific delivery of diagnostic and therapeutic agents. Since efficient uptake of drug carriers into target cells is central to effective drug delivery, a comprehensive understanding of the biological pathways for cellular internalization of DDS can facilitate the development of DDS capable of precise tissue targeting and enhanced therapeutic outcomes. Diverse methods have been applied to study the internalization mechanisms responsible for endocytotic uptake of extracellular materials, which are also the principal pathways exploited by many DDS. Chemical inhibitors remain the most commonly used method to explore endocytotic internalization mechanisms, although genetic methods are increasingly accessible and may constitute more specific approaches. This review highlights the molecular basis of internalization pathways most relevant to internalization of DDS, and the principal methods used to study each route. This review also showcases examples of DDS that are internalized by each route, and reviews the general effects of biophysical properties of DDS on the internalization efficiency. Finally, options for intracellular trafficking and targeting of internalized DDS are briefly reviewed, representing an additional opportunity for multi-level targeting to achieve further specificity and therapeutic efficacy.

Charge Reversion Simultaneously Enhances Tumor Accumulation and Cell Uptake of Layered Double Hydroxide Nanohybrids for Effective Imaging and Therapy

Nanotheranostics have been actively sought in precision nanomedicine in recent years. However, insufficient tumor accumulation and limited cell uptake often impede the nanotheranostic efficacy. Herein, pH-sensitive charge-reversible polymer-coated layered double hydroxide (LDH) nanohybrids are devised to possess long circulation in blood but reserve surface charges in the weakly acidic tumor tissue to re-expose therapeutic LDH nanoparticles for enhanced tumor accumulation and cell uptake. In vitro experimental data demonstrate that charge-reversible nanohybrids mitigate the cell uptake in physiological conditions (pH 7.4), but remarkably facilitate internalization by tumor cells after charge reversion in the weakly acidic environment (pH 6.8). More significantly, about 6.0% of injected charge-reversible nanohybrids accumulate in the tumor tissue at 24 h post injection, far higher than the average accumulation (0.7%) reported elsewhere for nanoparticles. This high tumor accumulation clearly shows the tumor tissues in T₁ -weighted magnetic resonance imaging. As a consequence, >95% inhibition of tumor growth in the B16F0-bearing mouse model is achieved via only one treatment combining RNAi and photothermal therapy under very mild irradiation (808 nm laser, 0.3 W cm^-2 for 180 s). The current research thus demonstrates a new strategy to functionalize nanoparticles and simultaneously enhance their tumor accumulation and cell internalization for effective cancer theranostics.

Novel zwitterionic vectors: Multi-functional delivery systems for therapeutic genes and drugs

Zwitterions consist of equal molar cationic and anionic moieties and thus exhibit overall electroneutrality. Zwitterionic materials include phosphorylcholine, sulfobetaine, carboxybetaine, zwitterionic amino acids/peptides, and other mix-charged zwitterions that could form dense and stable hydration shells through the strong ion-dipole interaction among water molecules and zwitterions. As a result of their remarkable hydration capability and low interfacial energy, zwitterionic materials have become ideal choices for designing therapeutic vectors to prevent undesired biosorption especially nonspecific biomacromolecules during circulation, which was termed antifouling capability. And along with their great biocompatibility, low cytotoxicity, negligible immunogenicity, systematic stability and long circulation time, zwitterionic materials have been widely utilized for the delivery of drugs and therapeutic genes. In this review, we first summarized the possible antifouling mechanism of zwitterions briefly, and separately introduced the features and advantages of each type of zwitterionic materials. Then we highlighted their applications in stimuli-responsive "intelligent" drug delivery systems as well as tumor-targeting carriers and stressed the multifunctional role they played in therapeutic gene delivery.

Aptamer-conjugated PLGA nanoparticles for delivery and imaging of cancer therapeutic drugs

Most problems associated with chemotherapeutic agents involve non-specific cytotoxicity, low intratumoral accumulation and drug resistance. Targeted drug delivery systems (TDDS) based on nanoparticles (NPs) are a new strategy for better therapeutic efficiency, along with reduction of side effects commonly seen with cancer drugs. Poly (lactic-co-glycolic acid) (PLGA), as one of the furthest developed synthetic polymer, has gained significant attention because of excellent properties-including biodegradability and biocompatibility, controlled release of drug, protection of drug or gene from decomposition and ability to modify surface with targeting agents for both cancer diagnosis and therapy. Aptamers are single-stranded RNA or DNA that can fold through intramolecular interactions into specific three-dimensional structures to selectively and exclusively bind with interested biomarkers. In this review, we explain the latest developments regarding the application of aptamer-decorated PLGA NPs in delivery of therapeutic agents or cancer-related genes into cancer cells. Additionally, we discuss the most recent efforts in the field of aptamer-grafted PLGA-based NPs as theranostics and stimuli-responsive agents.

Oleic Acid Copolymer as A Novel Upconversion Nanomaterial to Make Doxorubicin-Loaded Nanomicelles with Dual Responsiveness to pH and NIR

Oleic acid (OA) as main component of plant oil is an important solvent but seldom used in the nanocarrier of anticancer drugs because of strong hydrophobicity and little drug release. In order to develop a new type of OA nanomaterial with dual responses to pH and near infrared light (NIR) to achieve the intelligent delivery of anticancer drugs. The novel OA copolymer (mPEG-PEI-(NBS, OA)) was synthesized by grafting OA and o-nitrobenzyl succinate (NBS) onto mPEGylated polyethyleneimine (mPEG-PEI) by amidation reaction. It was further conjugated with NaYF₄:Yb³⁺/Er³⁺ nanoparticles, and encapsulated doxorubicin (DOX) through self-assembly to make upconversion nanomicelles with dual response to pH and NIR. Drug release behavior of DOX, physicochemical characteristics of the nanomicelles were evaluated, along with its cytotoxic profile, as well as the degree of cellular uptake in A549 cells. The encapsulation efficiency and drug loading capacity of DOX in the nanomicelles were 73.84% ± 0.58% and 4.62% ± 0.28%, respectively, and the encapsulated DOX was quickly released in an acidic environment exposed to irradiation at 980 nm. The blank nanomicelles exhibited low cytotoxicity and excellent biocompatibility by MTT assay against A549 cells. The DOX-loaded nanomicelles showed remarkable cytotoxicity to A549 cells under NIR, and promoted the cellular uptake of DOX into the cytoplasm and nucleus of cancer cells. OA copolymer can effectively deliver DOX to cancer cells and achieve tumor targeting through a dual response to pH and NIR.

Some Guidelines for the Synthesis and Melting Characterization of Azide Poly(ethylene glycol) Derivatives

We provide fundamental guidelines in the form of a tutorial to be taken into account for the preparation and characterization of a specific class of poly(ethylene glycol) (PEG) derivatives, namely azide-terminated PEGs. Special attention is given to the effect of these chain end groups and their precursors on properties affecting the PEGylation of proteins, nanoparticles and nanostructured surfaces. Notwithstanding the presence of 13C satellite peaks, we show that 1H NMR enables not only the routine quantitative determination of chain-end substitution, but is also a unique method to calculate the absolute number average molecular weight of PEG derivatives. In the use of size exclusion chromatography to get molecular weight distributions, we highlight the importance of distinguishing between eventual secondary reactions involving molecular weight changes and the formation of PEG complexes due to residual amounts of metal cations from reactants. Finally, we show that azide end groups affect PEG melting behavior. In contrast to oxygen-containing end groups, azides do not interact with PEG segments, thus inducing defect formation in the crystal lattice and the reduction of crystal sizes. Melting temperature and degree of crystallinity decrease become especially relevant for PEGs with very low molecular weight, and its comprehension is particularly important for solid-state applications.

Polyethylene glycol functionalized cerium oxide nanoparticle confer protection against UV- induced oxidative damage in skin: evidences for a new class of UV filter

Acute exposure to high dose of ultraviolet (UV) radiations is known to cause significant harm to skin, primarily due to the generation of free radicals and damage to DNA, which often culminate in rapid aging of the skin, or cancers. Keratinocytes being the most abundant skin’s cells are affected most by UV. Although a degree of endogenous protection is present, the vulnerability of UV-induced damaged can be minimized using protective agents. A few UV filters (organic and inorganic) have been successfully commercialized, yet, due to prevailing disadvantages such as low solubility, photostability, and aesthetic sense, suitable and more efficient UV filters continue to be explored as potential ingredients of cosmaceutical agents. A recently studied antioxidant enzyme mimetic cerium oxide nanoparticles showed emerging piece of evidence on benefits under environmental stress. However, its protective abilities as potential UV filter and therefore applicability in cosmaceutical has not yet been completely explored. This study provides a piece of evidence in support of beneficial effects of this new class of UV filters, polyethyleneglycol functionalized nanoceria (PEG-CNP) against UV - induced damage in vitro and in vivo. The nanomolar concentration of PEG-CNPs in the cell culture showed significant protection from UV exposure, by direct ROS scavenging, the rescue of cells from cell cycle arrest and DNA damage. Further, a proof of the concept study in dehaired rat skin showed that the topical application of 50 μM PEG-CNPs prevented the initial signs of UV induced damage. Unlike conventional UV filters, PEG-CNPs confer protection by internalizing the cells, and scavenging the radicals.

Self-assembled polydopamine nanoparticles improve treatment in Parkinson's disease model mice and suppress dopamine-induced dyskinesia

Although Levodopa (l-DOPA), a dopamine precursor, exhibits a high risk of dyskinesia, it remains the primary treatment in Parkinson's disease (PD), a progressive neurodegenerative disorder. In this study, we designed poly(l-DOPA)-based self-assembled nanodrug (Nano^DOPA) from amphiphilic block copolymer possessing poly(l-DOPA(OAc)₂), which is a precursor of l-DOPA as a hydrophobic segment, for treatment in a PD model mouse. Under physiological enzyme treatment, the poly(l-DOPA(OAc)₂) in the block copolymer was hydrolyzed to liberate l-DOPA gradually. Using the MPTP-induced PD mouse model, we observed that mice treated with Nano^DOPA demonstrated a significant improvement of PD symptoms compared to the l-DOPA treatment. Interestingly, the Nano^DOPA treatment did not cause the dyskinesia symptoms, which was clearly observed in the l-DOPA-treated mice. Furthermore, Nano^DOPA exhibited remarkably lower toxicity in vitro compared to l-DOPA, in addition with no noticeable Nano^DOPA toxicity observed in the treated mice. These results suggested that self-assembled Nano^DOPA is a promising therapeutic in the treatment of PD. STATEMENT OF SIGNIFICANCE: In this study, we proposed a therapeutic approach for the effective treatment of Parkinson's disease (PD) using newly designed poly(l-DOPA)-based self-assembled nanodrug (Nano^DOPA) prepared from amphiphilic block copolymers possessing poly(l-DOPA(OAc)₂), which is a precursor of l-DOPA as a hydrophobic segment, for treatment in a PD model mouse. Under physiological enzyme treatments, Nano^DOPA was hydrolyzed to liberate l-DOPA gradually, improving the pharmacokinetic value of l-DOPA. The mice treated with Nano^DOPA significantly improved PD symptoms compared to the l-DOPA treatment in a neurotoxin-induced PD mouse model. Interestingly, Nano^DOPA treatment did not cause dyskinesia symptoms, which was observed in the l-DOPA-treated mice. The obtained results in this study suggested that self-assembled Nano^DOPA is a promising therapeutic in the treatment of PD.

Anticancer activities of phytoconstituents and their liposomal targeting strategies against tumor cells and the microenvironment

Various bioactive ingredients have been extracted from Chinese herbal medicines (CHMs) that affect tumor progression and metastasis. To further understand the mechanisms of CHMs in cancer therapy, this article summarizes the effects of five categories of CHMs and their active ingredients on tumor cells and the tumor microenvironment. Despite their treatment potential, the undesirable physicochemical properties (poor permeability, instability, high hydrophilicity or hydrophobicity, toxicity) and unwanted pharmacokinetic profiles (short half-life in blood and low bioavailability) restrict clinical studies of CHMs. Therefore, development of liposomes through relevant surface modifying techniques to achieve targeted CHM delivery for cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature, have been reviewed. Current challenges of liposomal targeting of these phytoconstituents and future perspective of CHM applications are discussed to provide an informative reference for interested readers.

Numerical evaluation of polyethylene glycol ligand conjugation to gold nanoparticle surface using ToF-SIMS and statistical analysis

Nanoparticles (NPs) are substances between 1 and 100 nm in size. They have been the subject of numerous studies because of their potential applications in a wide range of fields such as cosmetics, electronics, medicine, and food. For biological applications of nanoparticles, they are usually coated with a substance capable of preventing agglomeration of the nanoparticles and nonspecific binding and exhibiting water-solubility characteristics with specific immobilized (bio)molecules. In order to evaluate the chemical properties of the surface-modified nanoparticles for bioapplications, including drug delivery, a simple and reliable method for the analysis of the presence of the surface chemicals and the ligand states of the nanoparticles is necessary. In this study, the authors numerically evaluated the extent of polyethylene glycol (PEG) ligand conjugation on AuNPs by concurrently adopting a microliquid inkjet printing system for sampling of the PEGylated AuNPs solution and ToF-SIMS imaging together with statistical analysis. The statistical correlation values calculated from the signals of PEG and Au measured by ToF-SIMS imaging on the sample spots made by a microliquid inkjet printing system showed better reproducibility and improved correlation values compared to the pipet spotting. Their improved method will be useful to evaluate ligand-conjugated nanoparticles for quality control of each conjugation process.

Synthesis and characterization of nanoemulsion-mediated core crosslinked nanoparticles, and in vivo pharmacokinetics depending on the structural characteristics

For designing nanoparticles as drug carriers, a covalently crosslinked structure is necessary for the structural stability in vivo. In this study, we prepared core crosslinked nanoparticles through the formation of nanoemulsions stabilized by poly(ethylene glycol) (PEG)-bearing surfactants. The structural characteristics of these particles were carefully evaluated using small-angle scattering techniques including dynamic, static, X-ray, and neutron scattering. The particles demonstrated high stability even in vivo, with the suppression of premature drug release owing to the crosslinked structure. Interestingly, the ability to retain encapsulated molecules was dependent on the molecular weight of PEG in vivo, presumably due to the difference in the crowding density of PEG chains at the outermost surface. This suggests that conferring structural stability via a core crosslinked structure is surely important, but we also need to consider controlling the crowding density of the hydrophilic polymer chains in the particle shell when designing drug carriers.

Development of effective AmB/AmB-αCD complex double loaded liposomes using a factorial design for systemic fungal infection treatment

Amphotericin B (AmB) is a very potent antibiotic which still remains as the gold standard for the treatment of systemic fungal infections. AmB is a member of Biopharmaceutical Classification System Class IV, mainly characterized by its poor solubility and low permeability. In this study, AmB/AmB-α cyclodextrin complex double loaded liposomes (DLLs) were developed using the design of experiments (DoE®) approach to optimize/determine the effects of lipid composition and other parameters on final product properties such as encapsulation efficacy, particle size, polydispersity index, and zeta potential. Experimental design 2⁴ was used for optimization of these properties in which four factors were studied in two levels. DLLs showed much higher physical stability than liposomes loaded only with free AmB by the means of particle size, zeta potential and encapsulation efficiency, in addition exhibited sustained release of AmB over 72 h (26.7%) with faster onset time. On the other hand, fourfold improved antimicrobial efficiency, minimum inhibitory concentration (0.125 µg/ml), and minimum fungicidal concentration (0.5 µg/ml) was determined by DLLs against C. albicans compared to Ambisome^®. Dose dependent effects of the DLLs were investigated by cytotoxicity studies on Vero and L-929 cells. No significant cytotoxicity observed for AmB/AmB-αCD complex DLLs and Ambisome at tested concentrations while free AmB caused severe cytotoxicity. Lastly the developed DLLs did not cause an increase in NGAL (an early biomarker for acute kidney toxicity) levels for both Vero and HK-2 cell lines compared to free AmB.

Silencing of p68 and STAT3 synergistically diminishes cancer progression

AIMS

Since several factors are involved in the tumorigenesis process, targeting only one factor most probably cannot overwhelm cancer progression. Therefore, it seems that combination therapy through targeting more than one cancer-related factor may lead to cancer control. The expression and function of p68 (DDX5; DEAD-Box Helicase 5) are dysregulated in various cancers. P68 is also a co-activator of many oncogenic transcription factors such as the signal transducer and activator of transcription-3 (STAT3), which contributes to cancer progression. This close connection between p68 and STAT3 plays an important role in the growth and development of cancer.

MATERIALS AND METHODS

We decided to suppress the p68/STAT3 axis in various cancer cells by using Polyethylene glycol-trimethyl Chitosan-Hyaluronic acid (PEG-TMC-HA) nanoparticles (NPs) loaded with siRNA molecules. We assessed the impact of this combination therapy on apoptosis, proliferation, angiogenesis, and tumor growth, both in vitro and in vivo.

KEY FINDINGS

The results showed that siRNA-loaded NPs notably suppressed the expression of p68/STAT3 axis in cancer cells, which was associated with blockade of tumor growth, colony formation, angiogenesis, and cancer cell migration. In addition to apoptosis induction, this combined therapy also reduced the expression of several tumor-promoting factors including Fibroblast growth factors (FGF), vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), matrix metallopeptidases-2 (MMP-2), MMP-9, hypoxia-inducible factor-(HIF-1α), interleukin-6 (IL-6), IL-33, Bcl-x, vimentin, and snail.

SIGNIFICANCE

These findings indicate the potential of this nano-based anti-cancer therapeutic strategy for efficient cancer therapy which should be further investigated in future studies.

Direct Comparison of Poly(ethylene glycol) and Phosphorylcholine Drug-Loaded Nanoparticles In Vitro and In Vivo

Phosphorylcholine is known to repel the absorption of proteins onto surfaces, which can prevent the formation of a protein corona on the surface of nanoparticles. This can influence the fate of nanoparticles used for drug delivery. This material could therefore serve as an alternative to poly(ethylene glycol) (PEG). Herein, the synthesis of different particles prepared by polymerization-induced self-assembly (PISA) coated with either poly(ethylene glycol) (PEG) or zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and 4-(N-(S-penicillaminylacetyl)amino) phenylarsenonous acid (PENAO) was reported. The anticancer drug 4-(N-(S-penicillaminylacetyl)amino) phenylarsenonous acid (PENAO) was conjugated to the shell-forming block. Interactions of the different coated nanoparticles, which present comparable sizes and size distributions (76-85 nm, PDI = 0.067-0.094), with two-dimensional (2D) and three-dimensional (3D) cultured cells were studied, and their cytotoxicities, cellular uptakes, spheroid penetration, and cell localization profiles were analyzed. While only a minimal difference in behaviour was observed for nanoparticles assessed using in vitro experiment (with PEG-co- PENAO-coated micelles showing slightly higher cytotoxicity and better spheroid penetration and cell localization ability), the effect of the different physicochemical properties between nanoparticles had a more dramatic effect on in vivo biodistribution. After 1 h of injection, the majority of the MPC-co-PENAO-coated nanoparticles were found to accumulate in the liver, making this particle system unfeasible for future biological studies.

c(RGDfK)- and ZnTriMPyP-Bound Polymeric Nanocarriers for Tumor-Targeted Photodynamic Therapy

Active targeting strategies are currently being extensively investigated in order to enhance the selectivity of photodynamic therapy. The aim of the present research was to evaluate whether the external decoration of nanopolymeric carriers with targeting peptides could add more value to a photosensitizer formulation and increase antitumor therapeutic efficacy and selectivity. To this end, we assessed PLGA-PLA-PEG nanoparticles (NPs) covalently attached to a hydrophilic photosensitizer 5-[4-azidophenyl]-10,15,20-tri-(N-methyl-4-pyridinium)porphyrinato zinc (II) trichloride (ZnTriMPyP) and also to c(RGDfK) peptides, in order to target α_v β₃ integrin-expressing cells. In vitro phototoxicity investigations showed that the ZnTriMPyP-PLGA-PLA-PEG-c(RGDfK) nanosystem is effective at submicromolar concentrations, is devoid of dark toxicity, successfully targets α_v β₃ integrin-expressing cells and is 10-fold more potent than related nanosystems where the PS is occluded instead of covalently bound.

Green Synthesis of Mg0.99 Zn0.01O Nanoparticles for the Fabrication of κ-Carrageenan/NaCMC Hydrogel in order to Deliver Catechin

Currently, the role of the nanoparticles in the structure of the composites and their benefits for the health of the body is valuable. In this study, the effects of the doping on the structural and morphological properties of the hydrogels using a Mg co-doped ZnO hydrogel, which has been fabricated by the sol–gel process, have been investigated. Then, a hydrogel containing nanoparticle and a hydrogel without any nanoparticles was produced as a control. The hydrogels were loaded with catechin and the related characterization was evolved based on the new structure of the matrices. The Mg_0.99Zn_0.01O nanoparticles were synthesized using a green synthesis method. To investigate the properties of the nanoparticles, zeta potential and XRD were studied. The field emission scanning electron microscopy (FESEM), FTIR, TGA, swelling Ratio, and compression tests were investigated for the hydrogels. Based on the results, FESEM showed a more compressed structure for hydrogels including nanoparticles rather than the hydrogels without a nanoparticle. The TGA showed a higher decomposition temperature in the hydrogels including nanoparticles. The swelling ratio of hydrogels containing a nanoparticle was higher than the control hydrogel. κ-Carrageenan/ Mg_0.99Zn_0.01O/NaCMC/Catechin had the highest swelling ratio (44.15%) rather than the κ-Carrageenan/NaCMC (33.22%). Mg_0.99Zn_0.01O nanoparticles presented a stronger structure of hydrogels in the compression test. It is concluded that the role of the synthesized nanoparticle is critical in the structure of the hydrogel.

Selective Control of Cell Activity with Hydrophilic Polymer-Covered Cationic Nanoparticles

Cationic polymers exhibit high cytotoxicity via strong interaction with cell membranes. To reduce cell membrane damage, a hydrophilic polymer is introduced to the cationic nanoparticle surface. The hydrophilic polymer coating of cationic nanoparticles resulted in a nearly neutral nanoparticle. These particles are applied to mouse fibroblast (3T3) and human cervical adenocarcinoma (Hela) cells. Interestingly, nanoparticles with a long cationic segment decrease cell activity regardless of cell type, while those with a short segment only affect 3T3 cell activity at lower concentrations less than 500 µg mL^-1 . Most nanoparticles are located inside 3T3 cells but on the cell membrane of Hela cells. The short cationic nanoparticle shows negligible cell membrane damage despite its high accumulation on Hela cell membranes. Cell activity changed by hydrophilic polymer-coated cationic nanoparticles is caused by incorporated nanoparticle accumulation in the cells, not cell membrane damage. To suppress the cytotoxicity from the cationic polymer, cationic nanoparticle needs to completely cover with hydrophilic polymer so as not to exhibit the cationic effect and applies to cell with low concentrations to reduce the nonselective cytotoxicity from the cationic polymer.

Reversal of multidrug resistance in leukemia cells using a transferrin-modified nanomicelle encapsulating both doxorubicin and psoralen

To ameliorate multidrug resistance (MDR) observed in leukemia cells, nanomicelles modified by transferrin (Tf-M-DOX/PSO), coencapsulating doxorubicin (DOX) and psoralen (PSO), were designed, synthesized and tested in K562 and doxorubicin-resistant K562 (K562/DOX) cells. In vitro drug release kinetics for constructed nanomicelles were measured using high-performance liquid chromatography. Characterization of the produced nanomicelles was completed using transmission electron microscopy and dynamic light scattering. Uptake of the nanomicelles in K562 cells was investigated using both confocal microscopy and flow cytometry. Apoptosis levels as well as the expression of glycoprotein (P-gp) were analyzing by western blotting and flow cytometry. Cellular cytotoxicity resulting from the exposure of nanomicelles was evaluated using MTT assays. The nanomicelles all showed mild release of DOX in PBS solution. In K562/DOX cells, Tf-M-Dox/PSO exhibited higher uptake compared to the other nanomicelles observed. Furthermore, cellular cytotoxicity when exposed to Tf-M-Dox/PSO was 2.8 and 1.6-fold greater than observed in the unmodified DOX and Tf-nanomicelles loaded with DOX alone, respectively. Tf-M-Dox/PSO strongly increased apoptosis of K562/DOX cells. Finally, the reversal of the drug resistance when cells are exposed to Tf-M-DOX/PSO was associated with P-gp expression inhibition. The Tf-M-Dox/PSO nanomicelle showed a reversal of MDR, with enhanced cellular uptake and delivery release.

Systemic Review of Biodegradable Nanomaterials in Nanomedicine

BACKGROUND

Nanomedicine is a field of science that uses nanoscale materials for the diagnosis and treatment of human disease. It has emerged as an important aspect of the therapeutics, but at the same time, also raises concerns regarding the safety of the nanomaterials involved. Recent applications of functionalized biodegradable nanomaterials have significantly improved the safety profile of nanomedicine.

OBJECTIVE

Our goal is to evaluate different types of biodegradable nanomaterials that have been functionalized for their biomedical applications.

METHOD

In this review, we used PubMed as our literature source and selected recently published studies on biodegradable nanomaterials and their applications in nanomedicine.

RESULTS

We found that biodegradable polymers are commonly functionalized for various purposes. Their property of being naturally degraded under biological conditions allows these biodegradable nanomaterials to be used for many biomedical purposes, including bio-imaging, targeted drug delivery, implantation and tissue engineering. The degradability of these nanoparticles can be utilized to control cargo release, by allowing efficient degradation of the nanomaterials at the target site while maintaining nanoparticle integrity at off-target sites.

CONCLUSION

While each biodegradable nanomaterial has its advantages and disadvantages, with careful design and functionalization, biodegradable nanoparticles hold great future in nanomedicine.

Modeling Nanocarrier Transport across a 3D In Vitro Human Blood-Brain-Barrier Microvasculature

Polymer nanoparticles (NPs), due to their small size and surface functionalization potential have demonstrated effective drug transport across the blood-brain-barrier (BBB). Currently, the lack of in vitro BBB models that closely recapitulate complex human brain microenvironments contributes to high failure rates of neuropharmaceutical clinical trials. In this work, a previously established microfluidic 3D in vitro human BBB model, formed by the self-assembly of human-induced pluripotent stem cell-derived endothelial cells, primary brain pericytes, and astrocytes in triculture within a 3D fibrin hydrogel is exploited to quantify polymer NP permeability, as a function of size and surface chemistry. Microvasculature are perfused with commercially available 100-400 nm fluorescent polystyrene (PS) NPs, and newly synthesized 100 nm rhodamine-labeled polyurethane (PU) NPs. Confocal images are taken at different timepoints and computationally analyzed to quantify fluorescence intensity inside/outside the microvasculature, to determine NP spatial distribution and permeability in 3D. Results show similar permeability of PS and PU NPs, which increases after surface-functionalization with brain-associated ligand holo-transferrin. Compared to conventional transwell models, the method enables rapid analysis of NP permeability in a physiologically relevant human BBB set-up. Therefore, this work demonstrates a new methodology to preclinically assess NP ability to cross the human BBB.

Zwitterion and Oligo(ethylene glycol) Synergy Minimizes Nonspecific Binding of Compact Quantum Dots

Quantum dots (QDs) are a class of fluorescent nanocrystals in development as labels for molecular imaging in cells and tissues. Recently, coatings for quantum dots based on multidentate polymers have improved labeling performance in a range of bioanalytical applications, primarily due to reduced probe hydrodynamic size. Now, an ongoing challenge is to eliminate nonspecific binding between these small probes and cellular components that mask specifically labeled molecules. Here, we describe insights into controlling and minimizing intermolecular interactions governing nonspecific binding using multidentate polymers with tunable hydrophilic functional groups that are cationic, anionic, zwitterionic (ZW), or nonionic (oligoethylene glycol; OEG). By fixing surface-binding groups and polymer length, coated colloids have similar sizes but diverse physicochemical properties. We measure binding to globular proteins, fixed cells, and living cells and observe a substantial improvement in nonspecific binding resistance when surfaces are functionalized with a combination of ZW and OEG. The independent underlying effects of counterion adsorption and flexibility appear to synergistically resist adsorption when combined, particularly for fixed cells enriched in both charged and hydrophobic moieties. We further show that ZW-OEG QDs are stable under diverse conditions and can be self-assembled with antibodies to specifically label surface antigens on living cells and cytoplasmic proteins in fixed cells. This surface engineering strategy can be adopted across the diverse range of colloidal materials currently in use and in development for biomedical applications to optimize their molecular labeling specificity.