Sugar Concentration and Arrangement on the Surface of Glycopolymer Micelles Affect the Interaction with Cancer Cells

Multifunctional theranostic glyconanoprobes for synergistic eradication of breast cancer

Theranostic agents hold great promise for personalized medicine by combining diagnostic and therapeutic functions. Herein, two novel multifunctional theranostic glyconanoprobes targeting breast cancer were engineered for synergistic dual chemo-gene therapy and triple chemo-gene-photothermal therapy. Upconversion nanoparticles (UCNPs) were prepared and coated with a Dox-loaded glycopeptide polymer (P-Dox) to form UCNP@P-Dox for improving stability. UCNP@MP-Dox equipped for triple therapy was prepared by combining UCNP@P-Dox with magnetic (Fe3O4, M) nanoparticles with photothermal properties. To regulate the expression of the anti-apoptotic Bcl-2 protein, both UCNP@P-Dox and UCNP@MP-Dox were loaded with anti-Bcl-2 siRNA. Impressive photothermal efficiency and good MRI contrast were demonstrated in preliminary evaluations. Moreover, the UCNP@P-Dox/siRNA nanoprobe for dual therapy was shown in preclinical studies to significantly increase anti-tumor efficacy. In vivo experiments in tumor-induced mice showed nanoprobe accumulation in tumors and enhanced antitumor efficacy with combinatorial therapy over Dox and siRNA alone. This study demonstrates the tumor-targeting capability of multifunctional theranostic glyconanoprobes, establishing chemo-gene synergy as a potent therapeutic strategy for breast cancer.

Synthesis and Characterization of Polyion Complex Micelles with Glycopolymer Shells for Drug Delivery Carriers

Double hydrophilic diblock copolymers (G20A100 and G100A98), composed of non-charged poly(glycosyloxyethyl methacrylate) (PGEMA, G) and cationic poly((3-acrylamidopropyl)trimethylammonium chloride), were synthesized via reversible addition-fragementation chain transfer (RAFT) radical polymerization. Likewise, diblock copolymers (G20S80 and G100S78), composed of PGEMA and anionic poly(2-acrylamido-2-methylpropanesulfonate) were synthesized via RAFT. The subscripts in these abbreviations indicate the degree of polymerization (DP) of each block. Polyion complex (PIC) aggregates (G20A100/G20S80 and G100A98/G100S78) were formed through electrostatic interactions by combining oppositely charged diblock copolymers with matched DPs for charge neutralization. The hydrodynamic radii of the G20A100/G20S80 and G100A98/G100S78 PIC aggregates were 77.4 and 26.2 nm, respectively, with zeta potentials close to 0 mV. The G20A100/G20S80 PIC micelles tend to form intermicellar aggregates, resulting in an increase in the particle size over time. In contrast, G100A98/G100S78 PIC micelles exhibited colloidal stability with a constant spherical core-shell shape, which was unaffected by time. The morphology and stability of the PIC aggregates depend upon the DP ratio of PGEMA and oppositely charged polyelectrolyte blocks. Both G20A100/G20S80 and G100A98/G100S78 PIC aggregates dissociated above 0.8 M NaCl due to the screening effect of NaCl.

Enhancing Targeted Photodynamic Therapy: Star-Shaped Glycopolymeric Photosensitizers for Improved Selectivity and Efficacy

Targeted photodynamic therapy (PDT) offers advantages over nontargeted approaches, including improved selectivity, efficacy, and reduced side effects. This study developed star-shaped glycopolymeric photosensitizers using porphyrin-based initiators via ATRP. Incorporating a porphyrin core gave the polymers fluorescence and ROS generation, while adding fructose improved solubility and targeting capabilities. The photosensitizers had high light absorption, singlet oxygen production, specificity, low dark toxicity, and biocompatibility. The glycopolymers with longer sugar arms and higher density showed better uptake on MCF-7 and MDA-MB-468 cells compared to HeLa cells, indicating enhanced targeting capabilities. Inhibition of endocytosis confirmed the importance of the GLUT5 receptor. The resulting polymers exhibited good cytocompatibility under dark conditions and satisfactory PDT under light irradiation. Interestingly, the polymers containing fructose have a GLUT5-dependent elimination effect on the MCF-7 and MDA-MB-468 cells. The intracellular ROS production followed a similar pattern, indicating that the fructose polymer exhibits specific targeting toward cells with GLUT5 receptors.

Structure-Controllable and Mass-Produced Glycopolymersomes as a Template of the Carbohydrate@Ag Nanobiohybrid with Inherent Antibacteria and Biofilm Eradication

Glycopolymer-supported silver nanoparticles (AgNPs) have demonstrated a promising alternative to antibiotics for the treatment of multidrug-resistant bacteria-infected diseases. In this contribution, we report a class of biohybrid glycopolymersome-supported AgNPs, which are capable of effectively killing multidrug-resistant bacteria and disrupting related biofilms. First of all, glycopolymersomes with controllable structures were massively fabricated through reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly (PISA) in an aqueous solution driven by complementary hydrogen bonding interaction between the pyridine and amide groups of N-(2-methylpyridine)-acrylamide (MPA) monomers. Subsequently, Ag+ captured by glycopolymersomes through the coordination between pyridine-N and Ag+ was reduced into AgNPs stabilized by glycopolymersomes upon addition of the NaBH4 reducing agent, leading to the formation of the glycopolymersome@AgNPs biohybrid. As a result, they showed a wide-spectrum and enhanced removal of multidrug-resistant bacteria and biofilms compared to naked AgNPs due to the easier adhesion onto the bacterial surface and diffusion into biofilms through the specific protein-carbohydrate recognition. Moreover, the in vivo results revealed that the obtained biohybrid glycopolymersomes not only demonstrated an effective treatment for inhibiting the cariogenic bacteria but also were able to repair the demineralization of caries via accumulating Ca2+ through the recognition between carbohydrates and Ca2+. Furthermore, glycopolymersomes@AgNPs showed quite low in vitro hemolysis and cytotoxicity and almost negligible acute toxicity in vivo. Overall, this type of biohybrid glycopolymersome@AgNPs nanomaterial provides a new avenue for enhanced antibacterial and antibiofilm activities and the effective treatment of oral microbial-infected diseases.

Optimized Carbohydrate-Based Nanogel Formulation to Sensitize Hypoxic Tumors

Solid tumors are often poorly vascularized, which impairs oxygen supply and drug delivery to the cells. This often leads to genetic and translational adaptations that promote tumor progression, invasion, metastasis, and resistance to conventional chemo-/radiotherapy and immunotherapy. A hypoxia-directed nanosensitizer formulation of a hypoxia-activated prodrug (HAP) was developed by encapsulating iodoazomycin arabinofuranoside (IAZA), a 2-nitroimidazole nucleoside-based HAP, in a functionally modified carbohydrate-based nanogel, facilitating delivery and accrual selectively in the hypoxic head and neck and prostate cancer cells. Although IAZA has been reported as a clinically validated hypoxia diagnostic agent, recent studies have pointed to its promising hypoxia-selective anti-tumor properties, which make IAZA an excellent candidate for further exploration as a multimodal theranostic of hypoxic tumors. The nanogels are composed of a galactose-based shell with an inner core of thermoresponsive (di(ethylene glycol) methyl ethyl methacrylate) (DEGMA). Optimization of the nanogels led to high IAZA-loading capacity (≅80-88%) and a slow time-controlled release over 50 h. Furthermore, nanoIAZA (encapsulated IAZA) displayed superior in vitro hypoxia-selective cytotoxicity and radiosensitization in comparison to free IAZA in the head and neck (FaDu) and prostate (PC3) cancer cell lines. The acute systemic toxicity profile of the nanogel (NG1) was studied in immunocompromised mice, indicating no signs of toxicity. Additionally, growth inhibition of subcutaneous FaDu xenograft tumors was observed with nanoIAZA, demonstrating that this nanoformulation offers a significant improvement in tumor regression and overall survival compared to the control.

RAFT aqueous dispersion polymerization of 4-hydroxybutyl acrylate: effect of end-group ionization on the formation and colloidal stability of sterically-stabilized diblock copolymer nanoparticles

Poly(2-hydroxyethyl acrylate)-poly(4-hydroxybutyl acrylate) nano-objects are prepared by aqueous polymerization-induced self-assembly (PISA) using an ionic RAFT agent.

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

Herein, the postfunctionalization of different non-fouling PISA particles, prepared from either poly(oligo ethylene glycol methyl ether methacrylate) (pPEGMA) and the anticancer drug PENAO (4-(N-(S-penicillaminylacetyl)amino)phenylarsenonous acid) or zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and PENAO were reported. Both PISA particles were reacted with triphenylphosphonium (TPP) as mitochondria targeting units in order to evaluate the changes in cellular uptake or the toxicity of the conjugated arsenic drug. Attachment of TPP onto the PISA particles however was found not to enhance the mitochondrial accumulation, but it did influence overall the biological activity of pMPC-based particles in 2D and 3D cultured sarcoma SW982 cells. When TPP was conjugated to the pMPC PISA particles more cellular uptake as well as better spheroid penetration were observed, while TPP on PEG-based PISA had only little effect. It was hypothesized that TPP on the micelle surface may not be accessible enough to allow mitochondria targeting, but more structural investigations are required to elucidate this.

Carbohydrate-Based Macromolecular Biomaterials

Carbohydrates are the most abundant and one of the most important biomacromolecules in Nature. Except for energy-related compounds, carbohydrates can be roughly divided into two categories: Carbohydrates as matter and carbohydrates as information. As matter, carbohydrates are abundantly present in the extracellular matrix of animals and cell walls of various plants, bacteria, fungi, etc., serving as scaffolds. Some commonly found polysaccharides are featured as biocompatible materials with controllable rigidity and functionality, forming polymeric biomaterials which are widely used in drug delivery, tissue engineering, etc. As information, carbohydrates are usually referred to the glycans from glycoproteins, glycolipids, and proteoglycans, which bind to proteins or other carbohydrates, thereby meditating the cell-cell and cell-matrix interactions. These glycans could be simplified as synthetic glycopolymers, glycolipids, and glycoproteins, which could be afforded through polymerization, multistep synthesis, or a semisynthetic strategy. The information role of carbohydrates can be demonstrated not only as targeting reagents but also as immune antigens and adjuvants. The latter are also included in this review as they are always in a macromolecular formulation. In this review, we intend to provide a relatively comprehensive summary of carbohydrate-based macromolecular biomaterials since 2010 while emphasizing the fundamental understanding to guide the rational design of biomaterials. Carbohydrate-based macromolecules on the basis of their resources and chemical structures will be discussed, including naturally occurring polysaccharides, naturally derived synthetic polysaccharides, glycopolymers/glycodendrimers, supramolecular glycopolymers, and synthetic glycolipids/glycoproteins. Multiscale structure-function relationships in several major application areas, including delivery systems, tissue engineering, and immunology, will be detailed. We hope this review will provide valuable information for the development of carbohydrate-based macromolecular biomaterials and build a bridge between the carbohydrates as matter and the carbohydrates as information to promote new biomaterial design in the near future.

Advances in amphiphilic polylactide/vinyl polymer based nano-assemblies for drug delivery

Micelles from self-assembled amphiphilic copolymers are highly attractive in drug delivery, due to their small size and hydrophilic stealth corona allowing prolonged lifetimes in the bloodstream and thus improved drug bioavailability. Polylactide (PLA)-based amphiphilic copolymer micelles are key candidates in this field, owing to the well-established biodegradability and biocompatibility of PLA. While PLA-b-poly(ethylene glycol) (PEG) block copolymer micelles can be seen as the "gold standard" in drug delivery research so far, the progresses in controlled radical polymerizations (Atom Transfer Radical Polymerization, Reversible Addition-Fragmentation Transfer and Nitroxide Mediated Polymerization) have offered new opportunities in the design of advanced amphiphilic copolymers for drug delivery due to their flexibility in many regards: (i) they can be easily combined with ring-opening polymerization (ROP) of lactide, with a diversity in types of architectures (e.g., block, graft, star), (ii) they allow (co)polymerization of a wide range of vinyl monomers, possibly circumventing PEG limitations, (iii) functionalization (with biomolecules or stimuli-cleavable moieties) is versatile due to end-group fidelity and copolymerization ability with reactive/functional comonomers. In this review, we report on the advances in the past decade of such amphiphilic PLA/vinyl polymer based nano-carriers, regarding key properties such as stealth character, cell targeting and stimuli-responsiveness.

Phthalocyanine-Conjugated Glyconanoparticles for Chemo-photodynamic Combination Therapy

Combination cancer therapy based on multifunctional nanomaterials has attracted great attention. The present work focuses on the preparation of the glycopolymeric nanoparticle, which contains a photosensitizer (zinc(II)phthalocyanine, ZnPc) and an anticancer drug (Doxorubicin, Dox). First, a novel mono azide-functional ZnPc-N₃ with seven hydrophilic ethylene oxide chains was synthesized. Next, ZnPc alone or together with Dox bearing glycopolymers was synthesized via the RAFT polymerization method and then self-assembled into glyconanoparticles (GNPs) with narrow particle size distribution. Then the evaluation of the biological activity of GNPs (GNPs-ZnPc and GNPs-ZnPc/Dox) for dual photodynamic therapy (PDT) and chemotherapy against human breast cancer cells was investigated. The constructed GNPs were identified via general characterization methods, including dynamic light scattering (DLS) and transmission electron microscopy (TEM). The prepared GNPs-ZnPc/Dox demonstrated remarkable photophysical and photochemical properties, involving good colloidal stability in biological conditions, pH-responsive drug release, and the capacity to generate singlet oxygen under light irradiation. The outer layer of nanoparticles covered by fructose sugar moieties achieves a targeted cancer therapy owing to GLUT5 (a well-known fructose transporter) overexpression toward breast cancer cells. In vitro experiments were then performed to evaluate the chemo/phototoxicity, cellular uptake, and anticancer efficacy of GNPs-ZnPc/Dox. In comparison with free Dox, human breast cancer cells treated with GNPs-ZnPc/Dox exhibited a higher cellular internalization via GLUT5 targeting. In particular, the GNPs-ZnPc/Dox nanoplatform revealed an excellent synergistic anticancer activity in comparison with free ZnPc-N₃ and free Dox, representing a novel and promising chemo-photodynamic combination therapeutic methodology to improve therapeutic efficacy.

The Protein Corona Leads to Deformation of Spherical Micelles

The formation of a non-specific protein corona around nanoparticles (NPs) has been identified as one of the culprits for failed nanomedicine. The amount and type of adsorbed protein from the blood plasma are known to determine the fate of NPs and the accessibility of targeting ligands. Herein, we show that the adsorbed protein may not only enlarge the NPs and change their surface properties but also, in the case of soft NPs such as polymer micelles, lead to deformation. Poly(1-O-methacryloyl -β-D-fructopyranose)-b-poly(methylmethacrylate) (P(1-O-MAFru)-b-PMMA) block co-polymers were self-assembled into NPs with a spherical core-shell morphology as determined by small angle neutron scattering (SANS). Upon incubation with albumin, TEM, SANS, and small angle X-ray scattering (SAXS) revealed the adsorption of albumin and deformation of the NPs with a spheroid geometry. Removal of the protein led to the reversal of the morphology back to the spherical core-shell structure. Structural studies and cell studies of uptake of the NPs imply that the observed deformation may influence blood circulation time and cell uptake.

Exploring the Toxicity, Lung Distribution, and Cellular Uptake of Rifampicin and Ascorbic Acid-Loaded Alginate Nanoparticles as Therapeutic Treatment of Lung Intracellular Infections

Nanotechnology is a very promising technological tool to combat health problems associated with the loss of effectiveness of currently used antibiotics. Previously, we developed a formulation consisting of a chitosan and tween 80-decorated alginate nanocarrier that encapsulates rifampicin and the antioxidant ascorbic acid (RIF/ASC), intended for the treatment of respiratory intracellular infections. Here, we investigated the effects of RIF/ASC-loaded NPs on the respiratory mucus and the pulmonary surfactant. In addition, we evaluated their cytotoxicity for lung cells in vitro, and their biodistribution on rat lungs in vivo after their intratracheal administration. Findings herein demonstrated that RIF/ASC-loaded NPs display a favorable lung biocompatibility profile and a uniform distribution throughout lung lobules. RIF/ASC-loaded NPs were mainly uptaken by lung macrophages, their primary target. In summary, findings show that our novel designed RIF/ASC NPs could be a suitable system for antibiotic lung administration with promising perspectives for the treatment of pulmonary intracellular infections.

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.

Glycopolymer decorated multiwalled carbon nanotubes for dual targeted breast cancer therapy

Carbon-based nanomaterials (CNMs) have attracted great attention in biomedical applications such as cancer imaging and therapy. CNMs, which are currently used in a wide range of applications, suffer from drawbacks of toxicity and low biocompatibility. Either noncovalent or covalent functionalization of CNMs with hydrophilic and biocompatible polymers which help to block hydrophobic interactivity between CNMs and cells can greatly increase their biocompatibility by eliminating their probable toxicity towards living organisms. In this report, we present a comparison of both noncovalent and covalent functionalization approaches in order to introduce a biocompatible glycoblock copolymer onto multi-walled carbon nanotubes (CNTs) in order to enhance their potential in therapies. An anticancer drug (doxorubicin, Dox) was conjugated with two different end functionalized poly(1-O-methacryloyl-β-d-fructopyranose-b-(2-methacryloxyethoxy))benzaldehyde glycoblock copolymers, which were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, by either noncovalent or covalent tethering. CNTs were coated separately with the synthesized drug-conjugated glycoblock copolymers and folic acid (FA) to obtain an efficient drug delivery platform for dual-targeting of glucose transporter protein (GLUT5) and folic acid receptors (FR) in breast cancer. A library of synthesized monomers, polymers and prepared glycoblock copolymer coated CNTs (hybrid-CNTs) using both approaches were comprehensively characterized by various techniques. Transmission electron microscopy measurements showed the homogeneous, smooth morphology of the prepared Dox-conjugated glycoblock copolymer coating of CNTs and confocal laser scanning microscopy images displayed successful cellular internalization of hybrid-CNTs in the MCF-7 and MDA-MB-231 human breast cancer cell lines. This research demonstrates the potential of hybrid-CNTs as a biocompatible drug delivery system as well as in vitro use of Dox-conjugated vehicles for dual receptor mediated breast cancer therapy.

Surface roughness influences the protein corona formation of glycosylated nanoparticles and alter their cellular uptake

Recently the role of protein absorption in nanoparticle drug delivery has gathered significant attention as the protein corona can significantly decide on the fate of nanoparticles in the body. Although it is known that the surface chemistry will significantly influence the amount and type of bound protein, there is little known about the effect of surface roughness and surface topography on the interaction. In this work, we show how patchy nanoparticles can noticeably reduce the adsorption of proteins compared to spherical nanoparticles with a smooth surface as demonstrated using six ABC triblock terpolymers based on glucose, mannose and galactose. To obtain patchy nanoparticles, poly(2-d-sugar ethyl acrylate)-b-poly (n-butyl acrylate)-b-poly(4-vinyl pyridine) (PSugEA-b-PBuA-b-P4VP) was prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization and assembled into nanoparticles with a patch-like appearance and a hydrodynamic diameter of around 130-160 nm. As control, smooth nanoparticles were prepared from poly(2-d-sugar ethyl acrylate)-b-poly (n-butyl acrylate)-b-polystyrene (PSugEA-b-PBuA-b-PS). The patchy nanoparticles displayed significantly reduced protein absorption when exposed to serum-supplemented cell culture media, as observed using dynamic light scattering. The smooth particles, however, supported the formation of a large protein corona. Additionally, an enrichment of haemoglobin was observed in the corona compared to the serum protein in solution. The amount of albumin on the surface was observed to be dependent on the type of sugar with glucose resulting in the highest absorption. The protein corona led to cellular uptake that was unrelated to the underlying sugar, which was supposed to help targeting specific cell lines. This example demonstrated how the protein corona can override any attempts to target receptor expressing cells.

Thermo/pH Responsive Star and Linear Copolymers Containing a Cholic Acid-Derived Monomer, N-Isopropylacrylamide and Acrylic Acid: Synthesis and Solution Properties

In this work three CTAs trithiocarbonate-type were synthesized-bifunctional (with PEG), trifunctional (with glycerol), and tetrafunctional (PERT)-and used in the controlled polymerization of 2-(acryloyloxy)ethyl cholate (CAE) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The resulting macroCTAs containing a cholic acid-derived polymer were chain extended with N-isopropylacrylamide with or without acrylic acid. The thermosensitive and/or pH properties of these copolymers were studied in PBS solutions. The copolymers synthesized without poly(acrylic acid) (PAAc) were unstable above the transition temperature. Similar behavior was observed for the copolymer solutions containing PAAc (2% in feed) at lower values of pH showing a faster precipitation above the LCST. On the contrary, copolymer solutions containing PAAc showed great stability at higher pH values for a longer time period at 37 °C. Interestingly, the Dh of the aggregates ranged from 18 to 30 nm in all copolymers (with or without PAAc) below the transition temperature, although the topology and the block sequence in the chain were significantly different.

A new 3D organotypic model of ovarian cancer to help evaluate the antimetastatic activity of RAPTA-C conjugated micelles

A novel 3D co-culture model of ovarian cancer can be used to test the efficacy of nanomedicine.