Dual drug delivery system of RAPTA-C and paclitaxel based on fructose coated nanoparticles for metastatic cancer treatment.

Ruthenium complexes have been widely studied as potential alternatives to platinum-type anticancer drugs due to their unique medical properties such as high selectivity, strong ability to inhibit solid tumour metastasis. However, non-specific biodistribution, and weak lethality of ruthenium to cancer cells limit its use in medical application. Drug delivery systems offer the ability to integrate multiple drugs in one system, which is particularly important to enhance the chemotherapeutic efficacy and to potentially achieve a synergistic effect of both drugs. Here, we report a dual drug nanocarrier that is based on a self-assembled biodegradable block copolymer, where the ruthenium complex (RAPTA-C) is chemically attached to the polymer chain, while another drug, paclitaxel (PTX), is entrapped in the core of the micelle. The dual drug delivery system was studied via in vitro tests using MDA-MB-231 breast cancer cells and it was observed that RAPTA-C in combination with PTX significantly enhanced anti-tumour and anti-metastasis activity.

Drug-Loading Content Influences Cellular Uptake of Polymer-Coated Nanocellulose.

While the effects of nanoparticle properties such as shape and size on cellular uptake are widely studied, influences exerted by drug loading have so far been ignored. In this work, nanocellulose (NC) coated by Passerini reaction with poly(2-hydroxy ethyl acrylate) (PHEA-g-NC) was loaded with various amounts of ellipticine (EPT) by electrostatic interactions. The drug-loading content was determined by UV-vis spectroscopy to range between 1.68 and 8.07 wt %. Dynamic light scattering and small-angle neutron scattering revealed an increased dehydration of the polymer shell with increasing drug-loading content, which led to higher protein adsorption and more aggregation. The nanoparticle with the highest drug-loading content, NC-EPT8.0, displayed reduced cellular uptake in U87MG glioma cells and MRC-5 fibroblasts. This also translated into reduced toxicity in these cell lines as well as the breast cancer MCF-7 and the macrophage RAW264.7 cell lines. Additionally, the toxicity in U87MG cancer spheroids was unfavorable. The nanoparticle with the best performance was found to have intermediate drug-loading content where the cellular uptake was adequately high while each nanoparticle was able to deliver a sufficiently toxic amount into the cells. Medium drug loading did not hinder uptake into cells while maintaining sufficiently toxic drug concentrations. It was concluded that while striving for a high drug-loading content is appropriate when designing clinically relevant nanoparticles, it needs to be considered that the drug can cause changes in the physicochemical properties of the nanoparticles that might cause unfavorable effects.

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

Glycopolymer-coated nanoparticles have attracted significant interest over the past few years, because of their selective interaction with carbohydrate receptors found on the surface of cells. While the type of carbohydrate determines the strength of the ligand-receptor interaction, the presentation of the sugar can be highly influential as the carbohydrate needs to be accessible in order to display good binding. To shine more light on the relationship between nanoparticle structure and cell uptake, we have designed several micelles based on fructose containing block copolymers, which are selective to GLUT5 receptors found on breast cancer cell lines. The polymers were based on poly-d,l-lactide (PLA), poly(2-hydroxyethyl) acrylate (PHEA), and poly(1- O-acryloyl-ß-d-fructopyranose) (P[1- O-AFru]). A set of six micelles was synthesized based on four fructose containing micelles (PLA242- b-P[1- O-AFru]41, PLA242- b-P[1- O-AFru]179, PLA242- b-P[1- O-AFru46-c-HEA214], PLA242- b-PHEA280- b-P[1- O-AFru]41) and two neutral controls (PLA247- b-PHEA53 and PLA247- b-PHEA166). SAXS analysis revealed that longer hydrophilic polymers led to lower aggregation numbers and larger hydrophilic shells, suggesting more glycopolymer mobility. Cellular uptake studies via flow cytometry and confocal laser scanning microscopy (CLSM) confirmed that the micelles based on PLA242- b-P[1- O-AFru]179 show, by far, the highest uptake by MCF-7 and MDA-MB-231 breast cancer cell lines while the uptake of all micelles by RAW264.7 cell is negligible. The same micelle displayed was far superior in penetrating MCF-7 cancer spheroids (three-dimensional (3D) model). Taking the physicochemical characterization obtained by SAXS and the in vitro results together, it could be concluded that the glycopolymer chains on the surface of micelle must display high mobility. Moreover, a high density of fructose was found to be necessary to achieve good biological activity as lowering the epitope density led immediately to lower cellular uptake. This work showed that it is crucial to understand the micelle structure in order to maximize the biological activity of glycopolymer micelles.

Direct Polymerization of the Arsenic Drug PENAO to Obtain Nanoparticles with High Thiol-Reactivity and Anti-Cancer Efficiency.

PENAO (4-(N-(S-penicillaminylacetyl)amino) phenylarsonous acid), which is a mitochondria inhibitor that reacts with adenine nucleotide translocator (ANT), is currently being trialed in patients with solid tumors. To increase the stability of the drug, the formation of nanoparticles has been proposed. Herein, the direct synthesis of polymeric micelles based on the anticancer drug PENAO is presented. PENAO is readily available for amidation reaction to form PENAO MA (4-(N-(S-penicillaminylacetyl) amino) phenylarsonous acid methacrylamide) which undergoes RAFT (reversible addition-fragmentation chain transfer) polymerization with poly(ethylene glycol methyl ether methacrylate) as comonomer and poly(methyl methacrylate) (pMMA) as chain transfer agent, resulting in p(MMA)-b-p(PEG-co-PENAO) block copolymers with 3-15 wt % of PENAO MA. The different block copolymers self-assembled into micelle structures, varying in size and stability (Dh = 84-234 nm, cmc = 0.5-82 µg mol-1) depending on the hydrophilic to hydrophobic ratio of the polymer blocks and the amount of drug in the corona of the particle. The more stable micelle structures were investigated toward 143B human osteosarcoma cells, showing an enhanced cytotoxicity and cellular uptake compared to the free drug PENAO (IC50 (PENAO) = 2.7 ± 0.3 µM; IC50 (micelle M4) = 0.8 ± 0.02 µM). Furthermore, PENAOs arsonous acid residue remains active when incorporated into a polymer matrix and conjugates to small mono and closely spaced dithiols and is able to actively target the mitochondria, which is PENAO's main target to introduce growth inhibition in cancer cells. As a result, no cleavable linker between drug and polymer was necessary for the delivery of PENAO to osteosarcoma cells. These findings provide a rationale for in vivo studies of micelle M4 versus PENAO in an osteosarcoma animal model.

Delivery of Amonafide from Fructose-Coated Nanodiamonds by Oxime Ligation for the Treatment of Human Breast Cancer.

The introduction of a strategy toward polymer/nanodiamond hybrids with high polymer grafting density and accessible polymer structural characterization is of critical importance for nanodiamonds' surface modification and bioagent attachment for their biomedical application. Here, we report a glycopolymer/nanodiamond hybrid drug delivery system, which was prepared by grafting amonafide-conjugated glycopolymers onto the surface of nanodiamonds via oxime ligation. Poly(1-O-methacryloyl-2,3:4,5-di-O-isopropylidene-ß-d-fructopyranose)-b-poly(3-vinylbenzaldehyde-co-methyl methacrylate), featuring pendant aldehyde groups, is prepared via RAFT polymerization. The anticancer drug amonafide is conjugated to the polymer chains via imine chemistry, resulting in acid-degradable imine linkages. The obtained amonafide-conjugated glycopolymers are subsequently grafted onto the surface of aminooxy-functionalized nanodiamonds via oxime ligation. The molecular weight of the conjugated polymers is characterized by size-exclusion chromatography (SEC), while the successful conjugation and corresponding grafting density is assessed by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric aanalysis (TGA). Our results indicate that the mass percentage of amonafide in the polymer chains is around 17% and the surface density of polymer chains is 0.24 molecules/nm2. The prepared drug delivery system has a hydrodynamic size around 380 nm with low PDI (0.3) and can effectively deliver amonafide into breast cancer cell and significantly inhibit the cancer cell viability. In 2D cell culture models, the IC50 values of ND-Polymer-AMF delivery system (7.19 µM for MCF-7; 4.92 µM for MDA-MB-231) are lower than those of free amonafide (11.23 µM for MCF-7; 13.98 µM for MDA-MB-231). An inhibited cell viability of nanodiamonds/polymer delivery system is also observed in 3D spheroids' models, suggesting that polymer-diamonds hybrid materials can be promising platforms for breast cancer therapy.

Influencing Selectivity to Cancer Cells with Mixed Nanoparticles Prepared from Albumin-Polymer Conjugates and Block Copolymers.

Albumin-based nanoparticles are widely used to delivery anticancer drug because they promote the accumulation of drugs in tumor sites. Nanoparticles with surface immobilized albumin are widely described in literature, although mixed nanoparticles with systematically modified ratios between albumin and PEG-based material are less common. In this work, hybrid nanoparticles were prepared by coassembly of a PEG-based amphiphilic block copolymer together with a polymer-protein conjugate. Poly(oligo(ethylene glycol) methyl ether acrylate)-poly(ε-caprolactone) (POEGMEA-PCL) was prepared by a combination of ring-opening polymerization and reversible addition-fragmentation chain transfer (RAFT) polymerization, while the polymer-protein conjugate was obtained by reacting poly(ε-caprolactone) with bovine serum albumin (BSA-PCL). Co-assembly of both amphiphiles at different ratios, with and without curcumin as a drug, led to hybrid nanoparticles with various amount of albumin on the particle surface. The resulting hybrid nanoparticles were similar in size (100-120 nm), but increasing the amount of albumin on the surface led to a more-negative ζ potential. The cytotoxicity of the curcumin-loaded nanoparticles was examined on several cell lines. The curcumin-loaded nanoparticles with high amount of albumin led to high cytotoxicity against breast cancer cell lines (MDA-MB-231 and MCF-7), which coincided with high cellular uptake. However, the cytotoxicity of the curcumin-loaded nanoparticles against CHO cells and RAW264.7 cells was reduced, suggesting that albumin can facilitate selectivity toward cancer cells.

Stabilization of Paclitaxel-Conjugated Micelles by Cross-Linking with Cystamine Compromises the Antitumor Effects against Two- and Three-Dimensional Tumor Cellular Models.

Paclitaxel (PTX)-conjugated micelles provide a promising tool for the treatment of prostate cancer. Core cross-linking by incorporating a disulfide bridge is a useful approach to improving the in vivo stability of polymeric micelles. This paper aims to investigate the effects of different degrees of cross-linking on the antitumor efficacy of micelles formed by poly(ethylene glycol methyl ether acrylate)-b-poly(carboxyethyl acrylate) (POEGMEA-b-PCEA-PTX) block copolymer. Both two-dimensional (2D) and three-dimensional (3D) in vitro prostate tumor cell models were used to evaluate the un-cross-linked and cross-linked micelles. The cytotoxicity decreased with an increase in the degree of cross-linking upon being tested with 2D cultured cells, and all micelles remained less cytotoxic than free PTX. In the 3D prostate MCTS model, however, there was no statistical difference between the performance of un-cross-linked micelles and free PTX, while increasing cross-linking densities led to significantly relevant decreases in the antitumor efficacy of micelles. These results are contradictory to our previous research using an irreversible cross-linker (1,8-diaminooctane) to stabilize POEGMEA-b-PCEA-PTX conjugate micelles where it was shown that cross-linking accelerates and improves the effects of the micelles when compared to those of un-cross-linked micelles. Further studies that aim to investigate the underlying mechanisms of disulfide bonds when micelles are internalized into cells are desired.

PEGylated Albumin-Based Polyion Complex Micelles for Protein Delivery.

An increasing amount of therapeutic agents are based on proteins. However, proteins as drug have intrinsic problems such as their low hydrolytic stability. Delivery of proteins using nanoparticles has increasingly been the focus of interest with polyion complex micelles, prepared from charged block copolymer and the oppositely charged protein, as an example of an attractive carrier for proteins. Inspired by this approach, a more biocompatible pathway has been developed here, which replaces the charged synthetic polymer with an abundant protein, such as albumin. Although bovine serum albumin (BSA) was observed to form complexes with positively charged proteins directly, the resulting protein nanoparticle were not stable and aggregated to large precipitates over the course of a day. Therefore, maleimide functionalized poly(oligo (ethylene glycol) methyl ether methacrylate) (MI-POEGMEMA) (Mn = 26000 g/mol) was synthesized to generate a polymer-albumin conjugate, which was able to condense positively charged proteins, here lysozyme (Lyz) as a model. The PEGylated albumin polyion complex micelle with lysozyme led to nanoparticles between 15 and 25 nm in size depending on the BSA to Lyz ratio. The activity of the encapsulated protein was tested using Sprouty 1 (C-12; Spry1) proteins, which can act as an endogenous angiogenesis inhibitor. Condensation of Spry1 with the PEGylated albumin could improve the anticancer efficacy of Spry1 against the breast cancer cells lowering the IC50 value of the protein. Furthermore, the high anticancer efficacy of the POEGMEMA-BSA/Spry1 complex micelle was verified by effectively inhibiting the growth of three-dimensional MCF-7 multicellular tumor spheroids. The PEGylated albumin complex micelle has great potential as a drug delivery vehicle for a new generation of cancer pharmaceuticals.

Fructose-Coated Nanodiamonds: Promising Platforms for Treatment of Human Breast Cancer.

Well-defined carboxyl end-functionalized glycopolymer Poly(1-O-methacryloyl-2,3:4,5-di-O-isopropylidene-ß-d-fructopyranose) (Poly(1-O-MAipFru)62) has been prepared via reversible addition-fragmentation chain transfer polymerization and grafted onto the surface of amine-functionalized nanodiamonds via a simple conjugation reaction. The properties of the nanodiamond-polymer hybrid materials ND-Poly(1-O-MAFru)62 are investigated using infrared spectroscopy, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The dispersibility of the nanodiamonds in aqueous solutions is significantly improved after the grafting of the glycopolymer. More interestingly, the cytotoxicity of amine-functionalized nanodiamonds is significantly decreased after decoration with the glycopolymer even at a high concentration (125 µg/mL). The nanodiamonds were loaded with doxorubicin to create a bioactive drug delivery carrier. The release of doxorubicin was faster in media of pH 5 than media of pH 7.4. The nanodiamond drug delivery systems with doxorubicin are used to treat breast cancer cells in 2D and 3D models. Although the 2D cell culture results indicate that all nanodiamonds-doxorubicin complexes are significantly less toxic than free doxorubicin, the glycopolymer-coated nanodiamonds-doxorubicin show higher cytotoxicity than free doxorubicin in the 3D spheroids after treatment for 8 days. The enhanced cytotoxicity of Poly(1-O-MAFru)62-ND-Dox in 3D spheroids may result from the sustained drug release and deep penetration of these nanocarriers, which play a role as a "Trojan Horse". The massive cell death after 8-day incubation with Poly(1-O-MAFru)62-ND-Dox demonstrates that glycopolymer-coated nanodiamonds can be promising platforms for breast cancer therapy.

Profluorescent PPV-Based Micellar System as a Versatile Probe for Bioimaging and Drug Delivery.

Although micelles are commonly used for drug delivery purposes, their long-term fate is often unknown due to photobleaching of the fluorescent labels or the use of toxic materials. Here, we present a metal-free, nontoxic, nonbleaching, fluorescent micelle that can address these shortcomings. A simple, yet versatile, profluorescent micellar system, built from amphiphilic poly(p-phenylenevinylene) (PPV) block copolymers, for use in drug delivery applications is introduced. Polymer micelles made from PPV show excellent stability for up to 1 year and are successfully loaded with anticancer drugs (curcumin or doxorubicin) without requiring introduction of physical or chemical cross-links. The micelles are taken up efficiently by the cells, which triggers disassembly, releasing the encapsulated material. Disassembly of the micelles and drug release is conveniently monitored as fluorescence of the single polymer chains appear, which enables not only to monitor the release of the payload, but in principle also the fate of the polymer over longer periods of time.

PEG Grafted-Nanodiamonds for the Delivery of Gemcitabine.

Carboxyl end-functionalized poly[poly(ethylene glycol) methyl ether methacrylate] [P(PEGMEMA)] and its block copolymer with gemcitabine substituted poly(N-hydroxysuccinimide methacrylate) [PGem-block-P(PEGMEMA)] are synthesized via reversible addition-fragmentation transfer (RAFT) polymerization. Then, two polymers are grafted onto the surface of amine-functionalized nanodiamonds to obtain [P(PEGMEMA)]-grafted nanodiamonds (ND-PEG) and [PGem-block-P(PEGMEMA)]-grafted nanodiamonds (ND-PF). Gemcitabine is physically absorbed to ND-PEG to produce ND-PEG (Gem). Two polymer-grafted nanodiamonds (i.e., with physically absorbed gemcitabine ND-PEG (Gem) and with chemically conjugated gemcitabine ND-PF) are characterized using attenuated total reflectance infrared spectroscopy, dynamic light scattering, and thermogravimetric analysis. The drug release, cytotoxicity (to seed human pancreatic carcinoma AsPC-1 cells), and cellular uptake of ND-PEG (Gem) and ND-PF are also investigated.

Core-Cross-Linking Accelerates Antitumor Activities of Paclitaxel-Conjugate Micelles to Prostate Multicellular Tumor Spheroids: A Comparison of 2D and 3D Models.

The 2D monolayer cell culture model is often the first step in the prediction of the success or failure of a nanoparticle-based drug delivery system. However, there is often poor translation between the 2D monolayer in vitro results and the nanoparticle-drug performance in vivo. One possible way of bridging this gap is the use of multicellular tumor spheroids (MCTSs) as an intermediate in vitro model due to its 3D structure. This paper aims to quantify and compare the results obtained from traditional 2D monolayer cell cultures and 3D MCTS by studying the cytotoxic effects of free paclitaxel (PTX) and paclitaxel, which has been conjugated to a poly(ethylene glycol methyl ether acrylate)-b-poly(carboxyethyl acrylate) (POEGMEA-b-PCEA-PTX) block copolymer and self-assembled to give a micellar delivery system. The core of the micelle was cross-linked with a diamino nondegradable cross-linker to compare the effects of micelle stability on the results. Although the 2D prostate tumor cell culture results indicated that all micellar variants (IC50: 193-271 nM) were significantly less toxic than free paclitaxel (IC50: 15.2 nM), the micelles showed faster and higher cytotoxicity than free PTX in the 3D prostate MCTS. The cross-linking of micelles even showed accelerated antitumor activities to the MCTS compared with un-cross-linked micelles. The results indicate that DAO-cross-linked POEGMEA-b-PCEA-PTX conjugate micelles will be a useful nanodrug carrier for prostate cancer therapy. MCTS offers a very promising method of incorporating 3D structures into in vitro testing.

Carbohydrate-Specific Uptake of Fucosylated Polymeric Micelles by Different Cancer Cell Lines.

Inspired by upregulated levels of fucosylated proteins on the surfaces of multiple types of cancer cells, micelles carrying ß-l-fucose and ß-d-glucose were prepared. A range of block copolymers were synthesized by reacting a mixture of 2-azidoethyl ß-l-fucopyranoside (FucEtN3) and 2-azideoethyl ß-d-glucopyranoside (GlcEtN3) with poly(propargyl methacrylate)-block-poly(n-butyl acrylate) (PPMA-b-PBA) using copper-catalyzed azide-alkyne cycloaddition (CuAAC). Five block copolymers were obtained ranging from 100 mol % fucose to 100% glucose functionalization. The resulting micelles had hydrodynamic diameters of around 30 nm. In this work, we show that fucosylated micelles reveal an increased uptake by pancreatic, lung, and ovarian carcinoma cell lines, whereas the uptake by the healthy cell lines (CHO) is negligible. This finding suggests that these micelles can be used for targeted drug delivery toward cancer cells.

Drug conjugation to cyclic peptide-polymer self-assembling nanotubes.

We show for the first time how polymeric nanotubes (NTs) based on self-assembled conjugates of polymers and cyclic peptides can be used as an efficient drug carrier. RAPTA-C, a ruthenium-based anticancer drug, was conjugated to a statistical co-polymer based on poly(2-hydroxyethyl acrylate) (pHEA) and poly(2-chloroethyl methacrylate) (pCEMA), which formed the shell of the NTs. Self-assembly into nanotubes (length 200-500 nm) led to structures exhibiting high activity against cancer cells.

Polyion complex micelle based on albumin-polymer conjugates: multifunctional oligonucleotide transfection vectors for anticancer chemotherapeutics.

Novel biocompatible polyion complex micelles, containing bovine serum albumin (BSA), polymer, and oligonucleotide, were synthesized as a generation of vectors for the gene transfection. Maleimide-terminated poly((N,N-dimethyl amino) ethyl methacrylate) (PDMAEMA) was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization and subsequently deprotected. Precise one to one albumin-PDMAEMA bioconjugates have been achieved via 1,4-addition with the free thiol group on Cys34 on the BSA protein. SDS-PAGE and GPC (water) confirmed and quantified the successful conjugation. The conjugation efficiency was found to be independent of the molecular weight of PDMAEMA. After careful pH adjustment, the conjugate could efficiently condense anticancer oligonucleotide, ISIS 5132, which resulted in particles of 15-35 nm with a negative zeta-potential. The size was easily controlled by the polymer chain length. The albumin corona provides complete protection of the cationic polymer and genetic drug, which gave rise to lower potential toxicity from the polymer and higher gene transfection efficiency. Although a control experiment with a traditional PEG-based polyion complex micelle could deliver the drug just as effectively, if not more so, to the ovarian cancer cell line OVCAR-3, this carrier had no selectivity toward cancerous cells and proved just as toxic to HS27 (fibroblast) cell line. In contrast, the albumin-coated particles demonstrated desirable selectivity toward cancerous cells and have been shown to have outstanding performance in the cytotoxicity tests of several carcinoma monolayer cell models. In addition, the complex micelles were able to destroy pancreatic multicellular tumor spheroids, while free ISIS 5132 could not penetrate the spheroid at all. Hence, albumin-coated/oligonucleotide complex micelles are far more promising than the most classical gene delivery vectors.

A bioactive calcium silicate nanowire-containing hydrogel for organoid formation and functionalization.

Organoids, which are 3D multicellular constructs, have garnered significant attention in recent years. Existing organoid culture methods predominantly utilize natural and synthetic polymeric hydrogels. This study explored the potential of a composite hydrogel mainly consisting of calcium silicate (CS) nanowires and methacrylated gelatin (GelMA) as a substrate for organoid formation and functionalization, specifically for intestinal and liver organoids. Furthermore, the research delved into the mechanisms by which CS nanowires promote the structure formation and development of organoids. It was discovered that CS nanowires can influence the stiffness of the hydrogel, thereby regulating the expression of the mechanosensory factor yes-associated protein (YAP). Additionally, the bioactive ions released by CS nanowires in the culture medium could accelerate Wnt/ß-catenin signaling, further stimulating organoid development. Moreover, bioactive ions were found to enhance the nutrient absorption and ATP metabolic activity of intestinal organoids. Overall, the CS/GelMA composite hydrogel proves to be a promising substrate for organoid formation and development. This research suggested that inorganic biomaterials hold significant potential in organoid research, offering bioactivities, biosafety, and cost-effectiveness.

Enhanced delivery of the RAPTA-C macromolecular chemotherapeutic by conjugation to degradable polymeric micelles.

Macromolecular ruthenium complexes are a promising avenue to better and more selective chemotherapeutics. We have previously shown that RAPTA-C [RuCl2(p-cymene)(PTA)], with the water-soluble 1,3,5-phosphaadamantane (PTA) ligand, could be attached to a polymer moiety via nucleophilic substitution of an available iodide with an amide in the PTA ligand. To increase the cell uptake of this macromolecule, we designed an amphiphilic block copolymer capable of self-assembling into polymeric micelles. The block copolymer was prepared by ring-opening polymerization of d,l-lactide (3,6-dimethyl-1,4-dioxane-2,5-dione) using a RAFT agent with an additional hydroxyl functionality, followed by the RAFT copolymerization of 2-hydroxyethyl acrylate (HEA) and 2-chloroethyl methacrylate (CEMA). The Finkelstein reaction and reaction with PTA led to polymers that can readily react with the dimer of RuCl2(p-cymene) to create a macromolecular RAPTA-C drug. RAPTA-C conjugation, micellization, and subsequent cytotoxicity and cell uptake of these polymeric moieties was tested on ovarian cancer A2780, A2780cis, and Ovcar-3 cell lines. Confocal microscopy images confirmed cell uptake of the micelles into the lysosome of the cells, indicative of an endocytic pathway. On average, a 10-fold increase in toxicity was found for the macromolecular drugs when compared to the RAPTA-C molecule. Furthermore, the cell uptake of ruthenium was analyzed and a significant increase was found for the micelles compared to RAPTA-C. Notably, micelles prepared from the polymer containing fewer HEA units had the highest cytotoxicity, the best cell uptake of ruthenium and were highly effective in suppressing the colony-forming ability of cells.

Folate conjugation to polymeric micelles via boronic acid ester to deliver platinum drugs to ovarian cancer cell lines.

In this study, a novel technique was used for the reversible attachment of folic acid on the surface of polymeric micelles for a tumor-specific drug delivery system. The reversible conjugation is based on the interaction between phenylboronic acid (PBA) and dopamine to form a borate ester. The conjugation is fast and efficient and in vitro experiments via confocal fluorescent microscopy show that the linker is stable in for several hours. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize two various sized water-soluble block copolymer of oligoethylene glycol methylether methacylate and methyl acrylic acid (POEGMEMA(35)-b-PMAA(200) and POEGMEMA(26)-b-PMAA(90)). The platinum drug, oxoplatin, was then subsequently attached to the polymer via ester formation leading to platinum loading of 12 wt % as determined by TGA. The platinum-induced amphiphilic block copolymers that consequently led to the formation of micelles of sizes 150 and 20 nm in an aqueous environment with the longer PMAA block forming larger micelles. The small micelles were in addition cross-linked using 1,8-diaminooctane to further stabilize their structure. The targeting ability of folate conjugated polymeric micelles was investigated against two types of tumor cell lines: A549 (-FR) and OVCAR-3 (+FR). The cell line growth inhibitory efficacy of material synthesized was evaluated by using SRB method. The results revealed that folate conjugated micelles showed higher activity in FR + OVCAR-3 cells but not in FR - A549 cells. Similar results were obtained for both small and large micelles without the conjugation of folate. Comparing large and small micelles it can be observed that larger micelles are more efficient, which has been attributed to the lower stability of the smaller micelles. Micelle stabilization via cross-linking could indeed increase the toxicity of the drug carrier.

Adipogenic differentiation of individual mesenchymal stem cell on different geometric micropatterns.

Micropatterned surfaces are very useful to control cell microenvironment and investigate the physical effects on cell function. In this study, poly(vinyl alcohol) (PVA) micropatterns on polystyrene cell-culture plates were prepared using UV photolithography. Cell adhesive polystyrene geometries of triangle, square, pentagon, hexagon, and circle were surrounded by cell nonadhesive PVA to manipulate cell shapes. These different geometries had the same small surface areas for cell spreading. Human mesenchymal stem cells (MSCs) were cultured on the micropatterned surface, and the effect of cell geometry on adipogenic differentiation was investigated. MSCs adhered to the geometric micropatterns and formed arrays of single cell with different shapes. The distribution patterns of actin filaments were similar among these cell shapes and remolded during adipogenesis. The adipogenic differentiation potential of MSCs was similar on the small size triangular, square, pentagonal, hexagonal, and circular geometries according to lipid vacuoles staining. This simple micropatterning technique using photoreactive molecules will be useful for creating micropatterns of arbitrary design on an organic surface, and cell functions can be directly and systematically compared on a single surface without external factors resulting from separate cell culture and coating method.

Mammary Tumor Organoid Culture in Non-Adhesive Alginate for Luminal Mechanics and High-Throughput Drug Screening.

Mammary tumor organoids have become a promising in vitro model for drug screening and personalized medicine. However, the dependency on the basement membrane extract (BME) as the growth matrices limits their comprehensive application. In this work, mouse mammary tumor organoids are established by encapsulating tumor pieces in non-adhesive alginate. High-throughput generation of organoids in alginate microbeads is achieved utilizing microfluidic droplet technology. Tumor pieces within the alginate microbeads developed both luminal- and solid-like structures and displayed a high similarity to the original fresh tumor in cellular phenotypes and lineages. The mechanical forces of the luminal organoids in the alginate capsules are analyzed with the theory of the thick-wall pressure vessel (TWPV) model. The luminal pressure of the organoids increase with the lumen growth and can reach 2 kPa after two weeks' culture. Finally, the mammary tumor organoids are treated with doxorubicin and latrunculin A to evaluate their application as a drug screening platform. It is found that the drug response is related to the luminal size and pressures of organoids. This high-throughput culture for mammary tumor organoids may present a promising tool for preclinical drug target validation and personalized medicine.