Glioblastoma (GBM) is the most common and lethal form of brain cancer. Its high mortality is associated with its aggressive invasion throughout the brain. The heterogeneity of stiffness and hyaluronic acid (HA) content within the brain makes it difficult to study invasion in vivo. A dextran‐bead assay is employed to quantify GBM invasion within HA‐functionalized gelatin hydrogels. Using a library of stiffness‐matched hydrogels with variable levels of matrix‐bound HA, it is reported that U251 GBM invasion is enhanced in softer hydrogels but reduced in the presence of matrix‐bound HA. Inhibiting HA–CD44 interactions reduces invasion, even in hydrogels lacking matrix‐bound HA. Analysis of HA biosynthesis suggests that GBM cells compensate for a lack of matrix‐bound HA by producing soluble HA to stimulate invasion. Together, a robust method is showed to quantify GBM invasion over long culture times to reveal the coordinated effect of matrix stiffness, immobilized HA, and compensatory HA production on GBM invasion.
Affinity‐based cell separation is label‐free and highly specific, but it is difficult to efficiently and gently release affinity‐captured cells due to the multivalent nature of cell‐material interactions. To address this challenge, we have developed a platform composed of a capture substrate and a cell‐releasing molecular trigger. The capture substrate is functionalized with a cell‐capture antibody and a coiled‐coil A . The cell‐releasing molecular trigger B ‐PEG (polyethylene glycol), a conjugate of a coiled‐coil B and polyethylene glycol, can drive efficient and gentle release of the captured cells, because A / B heterodimerization brings B ‐PEG to the substrate and PEG chains adopt extended conformations and break nearby multivalent antibody‐biomarker interactions. No enzymes or excessive shear stress are involved, and the released cells have neither external molecules attached nor endogenous cell‐surface molecules cleaved, which is critical for the viability, phenotype, and function of sensitive cells.
Well‐defined poly(ethylene glycol)‐b‐allyl functional polylactide‐b‐polylactides (PEG‐APLA‐PLAs) are synthesized through sequential ring‐opening polymerization. PEG‐APLA‐PLAs that have amphiphilic properties and reactive allyl side chains on their intermediate blocks are successfully transferred to core–shell interface cross‐linked micelles (ICMs) by micellization and UV‐initiated irradiation. ICMs have demonstrated enhanced colloidal stability in physiological‐mimicking media. Hydrophobic molecules such as Nile Red or doxorubicin (Dox) are readily loaded into ICMs; the resulting drug‐ICM formulations possess slow and sustained drug release profiles under physiological‐mimicking conditions. ICMs exhibit negligible cytotoxicity in human uterine sarcoma cancer cells by using biodegradable aliphatic polyester as the hydrophobic segments. Relative to free Dox, Dox‐loaded ICMs show a reduced cytotoxicity due to the late intracellular release of Dox from ICMs. Overall, ICMs represent a new type of biodegradable cross‐linked micelle and can be employed as a promising platform for delivering a broad variety of hydrophobic drugs.
Although chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western world, it remains incurable with conventional chemotherapeutic agents. Tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) is an antitumor candidate in cancer therapy. This study examines the proapoptotic effects of poly(propylene imine) (PPI) glycodendrimers modified with the maltotriose residues (PPI‐G4‐OS‐Mal‐III and PPI‐G4‐DS‐Mal‐III) on the TNF family in CLL cells. The combination of an understanding of the signaling pathways associated with CLL and the development of a molecular profiling is a key issue for the design of personalized approaches to therapy. Gene expression is determined with two‐color microarray 8 × 60K. The findings indicate that PPI‐G4‐OS/DS‐Mal‐III affect gene expression from the TRAIL apoptotic pathway and exert a strong effect on CLL cells comparable with fludarabine. Dendrimer‐targeted technology may well prove to bridge the gap between the ineffective treatment of today and the effective personalized therapy of the future.
Stimuli‐responsive nanocarriers with the ability to respond to tumorous heterogeneity have been extensively developed for drug delivery. However, the premature release during blood circulation and insufficient intracellular drug release are still a significant issue. Herein, three disulfide bonds are introduced into the amphiphilic poly(ethylene glycol)‐polycaprolactone copolymer blocks to form triple‐sensitive cleavable polymeric nanocarrier (tri‐PESC NPs) to improve its sensitivity to narrow glutathione (GSH) concentration. The tri‐PESC NPs keep intact during blood circulation due to the limited cleaving of triple‐disulfide bonds, whereas the loaded drug is efficiently released at tumor cells with the increased concentration of GSH. In vitro studies of doxorubicin‐loaded tri‐PESC NPs show that the nanocarriers achieve sufficient drug release in cancerous cells and inhibit the tumor cells growth, though they only bring minimum damage to normal cells. Therefore, the tri‐PESC NPs with triple‐sensitive cleavable bonds hold great promise to improve the therapeutic index in cancer therapy.
The authors report a method to prepare cell‐laden, cell‐sized microparticles from various materials suitable for individual applications. The method includes a piezoelectric inkjetting technology and a horseradish peroxidase (HRP)‐catalyzed crosslinking reaction. The piezoelectric inkjetting technology enables production of cell‐laden, cell‐sized (20–60 μm) droplets from a polymer aqueous solution. The HRP‐catalyzed crosslinking of the polymer in the ejected solution enables production of spherical microparticles from various materials. Superior cytocompatibility of the microencapsulation method is confirmed from the viability and growth profiles of normal murine mammary gland epithelial cells.
There is an urgent unmet medical need for new treatments for wound and burn infections caused by multidrug‐resistant Gram‐negative “superbugs,” especially the problematic Pseudomonas aeruginosa . In this work, the incorporation of colistin, a potent lipopeptide into a self‐healable hydrogel (via dynamic imine bond formation) following the chemical reaction between the amine groups present in glycol chitosan and an aldehyde‐modified poly(ethylene glycol), is reported. The storage module (G ′) of the colistin‐loaded hydrogel ranges from 1.3 to 5.3 kPa by varying the amount of the cross‐linker and colistin loading providing different options for topical wound healing. The majority of the colistin is released from the hydrogel within 24 h and remains active as demonstrated by both antibacterial in vitro disk diffusion and time‐kill assays. Moreover and pleasingly, the colistin‐loaded hydrogel performs almost equally well as native colistin against both the colistin‐sensitive and also colistin‐resistant P. aeruginosa strain in the in vivo animal “burn” infection model despite exhibiting a slower killing profile in vitro. Based on this antibiotic performance along with the biodegradability of the product, it is believed the colistin‐loaded hydrogel to be a potential localized wound‐healing formulation to treat burn wounds against microbial infection.
In this study, heparin‐mimicking hydrogel thin films are covalently attached onto poly(ether sulfone) membrane surfaces to improve anticoagulant property. The hydrogel films display honeycomb‐like porous structure with well controlled thickness and show long‐term stability. After immobilizing the hydrogel films, the membranes show excellent anticoagulant property confirmed by the activated partial thromboplastin time values exceeding 600 s. Meanwhile, the thrombin time values increase from 20 to 61 s as the sodium allysulfonate proportions increase from 0 to 80 mol%. In vitro investigations of protein adsorption and blood‐related complement activation also confirm that the membranes exhibit super‐anticoagulant property. Furthermore, gentamycin sulfate is loaded into the hydrogel films, and the released drug shows significant inhibition toward E. coli bacteria. It is believed that the surface attached heparin‐mimicking hydrogel thin films may show high potential for the applications in various biological fields, such as blood contacting materials and drug loading materials.
Applications of enzymes are intensively studied, particularly for biomedical applications. However, encapsulation or immobilization of enzymes without deactivation and long‐term use of enzymes are still at issue. This study focuses on the polymeric vesicles “PICsomes” for encapsulation of enzymes to develop a hecto‐nanometer‐scaled enzyme‐loaded reactor. The catalytic activity of a PICsome‐based enzyme nanoreactor is carefully examined to clarify the effect of compartmentalization by PICsome. Encapsulation by PICsome provides a stability enhancement of enzymes after 24 h incubation at 37 °C, which is particularly helpful for maintaining the high effective concentration of β‐galactosidase. Moreover, to control the microenvironment inside the nanoreactor, a large amount of dextran, a neutral macromolecule, is encapsulated together with β‐galactosidase in the PICsome. The resulting dextran‐coloaded nanoreactor contributes to the enhancement of enzyme stability, even after exposure to 24 h incubation at −20 °C, mainly due to the antifreezing effect.
Bone related problems are increasing as a consequence of increased life expectancy, disorders in life style, and other medical conditions enforcing the need for functional bones prepared in vitro at affordable cost. Lack of suitable surface which promotes growth of both osteogenic and nonosteogenic cells is a major limitation. Here a novel biomaterial is reported that is synthesized from natural polysaccharide, namely, tamarind kernel polysaccharide (TKP), which is grafted with hydrophilic acrylic acid (AA) by radical polymerization. Modification in surface functionality removes unwanted proteins and alters hydrophilic/hydrophobic balance. TKP‐AA is suitable for the growth of different nonosteogenic and osteogenic cells. This material is suitable for osteoblasts and promotes in vitro mineralization and differentiation without the addition of exogenous growth factors. TKP‐AA can be used for the growth of mesenchymal stem cell‐derived osteoblasts. It is suggested that TKP‐AA can potentially be used as a scaffold for diverse cell types and particularly for bone tissue engineering at low cost.
Platinum‐based chemotherapy has been widely used to treat cancers including ovarian cancer; however, it suffers from dose‐limiting toxicity. Judiciously designed drug nanocarriers can enhance the anticancer efficacy of platinum‐based chemotherapy while reducing its systemic toxicity. Herein the authors report a stable and water‐soluble unimolecular nanoparticle constructed from a hydrophilic multi‐arm star block copolymer poly(amidoamine)‐b‐poly(aspartic acid)‐b‐poly(ethylene glycol) (PAMAM‐PAsp‐PEG) conjugated with both cRGD (cyclo(Arg‐Gly‐Asp‐D‐Phe‐Cys) peptide and cyanine5 (Cy5) fluorescent dye as a platinum‐based drug nanocarrier for targeted ovarian cancer therapy. Carboplatin is complexed to the poly(aspartic acid) inner shell via pH‐responsive ion–dipole interactions between carboplatin and the carboxylate groups of poly(aspartic acid). Based on flow cytometry and confocal laser scanning microscopy analyses, cRGD‐conjugated unimolecular nanoparticles exhibit much higher cellular uptake by ovarian cancer cells overexpressing αvβ3 integrin than nontargeted (i.e., cRGD‐lacking) ones. Carboplatin‐complexed cRGD‐conjugated nanoparticles also exhibit higher cytotoxicity than nontargeted nanoparticles as well as free carboplatin, while empty unimolecular nanoparticles show no cytotoxicity. These results indicate that stable unimolecular nanoparticles made of individual hydrophilic multi‐arm star block copolymer molecules conjugate with tumor‐targeting ligands and dyes (i.e., PAMAM‐PAsp‐PEG‐cRGD/Cy5) are promising nanocarriers for platinum‐based anticancer drugs for targeted cancer therapy.
Colorectal peritoneal carcinomatosis (CRPC) is a common systemic metastasis of intra‐abdominal cancers. Intraperitoneal chemotherapy against CRPC is at present the preferred treatment. The aim of this study is to develop a novel hydrogel drug delivery system through the combination of 5‐fluorouracil (5‐FU) loaded polymeric micelles and cisplatin (DDP) in biodegradable thermosensitive chitosan (CS) hydrogel. The prepared CS hydrogel drug is a free‐flowing solution at room temperature and forms a stationary gel at body temperature. Therefore, a CRPC mouse model is established to investigate the antitumor activity of CS hydrogel drug system. The results suggest that intraperitoneal administration of CS hydrogel drug can inhibit tumor growth and metastasis, and prolong survival time compared with other groups, thus improving the chemotherapeutic effect. Ki‐67 immunohistochemical analysis reveals that tumors in the CS hydrogel drug group has lower cell proliferation in contrast to other groups (P < 0.001). Furthermore, hematoxylin‐eosin staining of liver and lung tissue indicates that the CS hydrogel drug has also a certain inhibitory effect on colorectal cancer metastasis to the liver and lung. Hence, the work highlights the potential clinical applications of the CS hydrogel drug.
d ‐Fructose modified poly(ε‐caprolactone)‐polyethylene glycol (PCL‐PEG‐Fru) diblock amphiphile is synthesized via Cu(I)‐catalyzed click chemistry, which self‐assembles with D‐α‐tocopheryl polyethylene glycol 1000 succinate (TPGS) into PCL‐PEG‐Fru/TPGS mixed micelles (PPF MM). It has been proven that glucose transporter (GLUT)5 is overexpressed in MCF‐7 cells other than L929 cells. In this study, PPF MM exhibit a significantly higher uptake efficiency than fructose‐free PCL‐PEG‐N3/TPGS mixed micelles in both 2D MCF‐7 cells and 3D tumor spheroids. Also, the presence of free d ‐fructose competitively inhibits the internalization of PPF MM in MCF‐7 cells other than L929 cells. PPF MM show selective tumor accumulation in MCF‐7 breast tumor bearing mice xenografts. Taken together, PPF MM represent a promising nanoscale carrier system to achieve GLUT5‐mediated cell specific delivery in cancer therapy.
Graphene oxide (GO) has received increasing attention in bioengineering fields due to its unique biophysical and electrical properties, along with excellent biocompatibility. The application of GO nanoparticles (GO‐NPs) to engineer self‐renewal and differentiation of human fetal neural stem cells (hfNSCs) is reported. GO‐NPs added to hfNSC culture during neurosphere formation substantially promote cell‐to‐cell and cell‐to‐matrix interactions in neurospheres. Accordingly, GO‐NP‐treated hfNSCs show enhanced self‐renewal ability and accelerated differentiation compared to untreated cells, indicating the utility of GO in developing stem cell therapies for neurogenesis.
Hemocompatibility and cytocompatibility of biomaterials codetermine the success of tissue engineering applications. DNA, the natural component of our cells, is an auspicious biomaterial for the generation of designable scaffolds with tailorable characteristics. In this study, a combination of rolling circle amplification and multiprimed chain amplification is used to generate hydrogels at centimeter scale consisting solely of DNA. Using an in vitro rotation model and fresh human blood, the reaction of the hemostatic system on DNA hydrogels is analyzed. The measurements of hemolysis, platelets activation, and the activation of the complement, coagulation, and neutrophils using enzyme‐linked immunosorbent assays demonstrate excellent hemocompatibility. In addition, the cytocompatibility of the DNA hydrogels is tested by indirect contact (agar diffusion tests) and material extract experiments with L929 murine fibroblasts according to the ISO 10993‐5 specifications and no negative impact on the cell viability is detected. These results indicate the promising potential of DNA hydrogels as biomaterials for versatile applications in the field of regenerative medicine.
A simple and rapid process for multiscale printing of bioinks with dot widths ranging from hundreds of microns down to 0.5 μm is presented. The process makes use of spontaneous surface charges generated pyroelectrically that are able to draw little daughter droplets directly from the free meniscus of a mother drop through jetting (“p‐jet”), thus avoiding time‐consuming and expensive fabrication of microstructured nozzles. Multiscale can be easily achieved by modulating the parameters of the p‐jet process. Here, it is shown that the p‐jet allows us to print well‐defined adhesion islands where NIH‐3T3 fibroblasts are constrained to live into cluster configurations ranging from 20 down to single cell level. The proposed fabrication approach can be useful for high‐throughput studies on cell adhesion, cytoskeleton organization, and stem cell differentiation.
Aggregation‐caused quenching (ACQ) is a general phenomenon that is faced by traditional fluorescent polymers. Aggregation‐induced emission (AIE) is exactly opposite to ACQ. AIE molecules are almost nonemissive in their molecularly dissolved state, but they can be induced to show high fluorescence in the aggregated or solid state. Incorporation of AIE phenomenon into polymer design has yielded various polymers with AIE characteristics. In this review, the recent progress of AIE polymers for biological applications is summarized.
Tissue expansion is used by plastic/reconstructive surgeons to grow additional skin/tissue for replacing or repairing lost or damaged soft tissues. Recently, hydrogels have been widely used for tissue expansion applications. Herein, a self‐inflating tissue expander blend composition from three different molecular weights (2, 6, and 10 kDa) of poly (ethylene glycol) diacrylate (PEGDA) hydrogel with tunable mechanical and swelling properties is presented. The in vitro results demonstrate that, of the eight studied compositions, P6 (PEGDA 6 kDa:10 kDa (50:50)) and P8 (PEGDA 6 kDa:10 kDa (35:65)) formulations provide a balance of mechanical property and swelling capability suitable for tissue expansion. Furthermore, these expanders can be compressed up to 60% of their original height and can be loaded and unloaded cyclically at least ten times with no permanent deformation. The in vivo results indicate that these two engineered blend compositions are capable to generate a swelling pressure sufficient to dilate the surrounding tissue while retaining their original shape. The histological analyses reveal the formation of fibrous capsule at the interface between the implant and the subcutaneous tissue with no signs of inflammation. Ultimately, controlling the PEGDA chain length shows potential for the development of self‐inflating tissue expanders with tunable mechanical and swelling properties.
The high affinity of GLUT5 transporter for d ‐fructose in breast cancer cells has been discussed intensely. In this contribution, high molar mass linear poly(ethylene imine) (LPEI) is functionalized with d ‐fructose moieties to combine the selectivity for the GLUT5 transporter with the delivery potential of PEI for genetic material. The four‐step synthesis of a thiol‐group bearing d ‐fructose enables the decoration of a cationic polymer backbone with d ‐fructose via thiol‐ene photoaddition. The functionalization of LPEI is confirmed by 2D NMR techniques, elemental analysis, and size exclusion chromatography. Importantly, a d ‐fructose decoration of 16% renders the polymers water‐soluble and eliminates the cytotoxicity of PEI in noncancer L929 cells, accompanied by a reduced unspecific cellular uptake of the genetic material. In contrast, the cytotoxicity as well as the cell specific uptake is increased for triple negative MDA‐MB‐231 breast cancer cells. Therefore, the introduction of d ‐fructose shows superior potential for cell targeting, which can be assumed to be GLUT5 dependent.
The synthesis of a novel photoreactive poly(ethylene glycol) (PEG)‐based polymer with caged carbonyl groups is reported. We further demonstrate its use for the on‐demand fabrication of hydrogels. For rapid gelation, a hydrazide‐functionalized PEG is used as the second component for the hydrogel preparation. The photoreactive PEG‐based polymer is designed for controlled cleavage of the protecting groups upon exposure to UV light releases free aldehyde moieties, which readily react with hydrazide groups in situ. This hydrogel system may find applications in controlled release drug delivery applications, when combined with in situ gelation. Furthermore, the possibility of forming gels specifically upon UV irradiation gives an opportunity for 3D fabrication of degradable scaffolds.
