Cell sorting is important for cell biology and regenerative medicine. A visible light‐responsive cell scaffold is produced using gold nanoparticles and collagen gel. Various kinds of cells are cultured on the visible light‐responsive cell scaffold, and the target cells are selectively detached by photoirradiation without any cytotoxicity. This is a new image‐guided cell sorting system.
The fabrication of nanodiamond (ND)‐based drug carriers for tumor‐targeted drug delivery is described. The ND clusters with an average size of 52.84 nm are fabricated using a simple fluidic device combined with a precipitation method and then conjugated with folic acid (FA) and doxorubicin (Dox) via carbodiimide chemistry to obtain FA/Dox‐modified ND (FA/Dox‐ND) clusters. Cell culture experiments revealed that KB (folate receptor‐positive) cells are preferentially ablated by FA/Dox‐ND clusters compared to A549 (folate receptor‐negative) cells. In vivo results revealed that FA/Dox‐ND clusters are specifically accumulated in tumor tissues after intravenous injection into tumor‐bearing mice, effectively reducing the volume of tumor. Based on these results, this study suggests that FA/Dox‐ND clusters can be a good candidate as tumor‐targeted nanovehicles for delivery of antitumor drug.
Multivalent aptamer–siRNA conjugates containing multiple mucin‐1 aptamers and BCL2‐specific siRNA are synthesized, and doxorubicin, an anthracycline anticancer drug, is loaded into these conjugates through intercalation with nucleic acids. These doxorubicin‐incorporated multivalent aptamer–siRNA conjugates are transfected to mucin‐1 overexpressing MCF‐7 breast cancer cells and their multidrug‐resistant cell lines. Doxorubicin‐incorporated multivalent aptamer–siRNA conjugates exert promising anticancer effects, such as activation of caspase‐3/7 and decrease of cell viability, on multidrug‐resistant cancer cells because of their high intracellular uptake efficiency. Thus, this delivery system is an efficient tool for combination oncotherapy with chemotherapeutics and nucleic acid drugs to overcome multidrug resistance.
A unique l ‐cysteine conjugated antifouling amphiphilic conetwork (APCN) is synthesized through end‐crosslinking of well‐defined triblock copolymers poly(allyl methacrylate)‐b‐poly(ethylene glycol)‐b‐poly(allyl methacrylate) via a combination of reversible addition‐fragmentation chain transfer (RAFT) polymerization and thiol–ene “click” chemistry. The synthesized poly(ethylene glycol) macro‐RAFT agent initiates the polymerization of allyl methacrylate in a controlled manner. The vinyl pendant groups of the precursor partially conjugate with l ‐cysteine and the rest fully crosslink with mercaptopropyl‐containing siloxane via thiol–ene click chemistry under UV irradiation into APCNs, which show distinguished properties, that is, excellent biocompatibility, more than 39.6% water content, 101 barrers oxygen permeability, optimized mechanical properties, and more than 93% visible light transmittance. What's more, the resultant APCNs exhibit eminent resistance to protein adsorption, where the bovine serum albumin and lysozyme adsorption are decreased to 12 and 21 µg cm−2, respectively. The outstanding properties of APCNs depend on the RAFT controlled method, which precisely designs the hydrophilic/hydrophobic segments and eventually greatly improves the crosslinking efficiency and homogeneity. Meantime, the l ‐cysteine monolayer can effectively reduce the surface hydrophobicity and prevent protein adsorption, which exhibits the viability for antifouling surface over and under ophthalmic devices, suggesting a promising soft contact lens.
To enhance the limited degradability of poly(ethylene glycol) (PEG), a straightforward method of synthesizing poly[(ethylene glycol)‐co‐(glycolic acid)] (P(EG‐co‐GA)) via a ruthenium‐catalyzed, post‐polymerization oxyfunctionalization of various PEGs is developed. Using this method, a set of copolymers with GA compositions of up to 8 mol% are prepared with minimal reduction in molecular weight (<10%) when compared to their commercially available starting materials. The P(EG‐co‐GA) copolymers are shown to undergo hydrolysis under mild conditions.
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.
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 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.
Microparticulate systems composed of biodegradable polymers, such as poly(d ,l ‐lactic‐co‐glycolic acid) (PLGA), are widely used for controlled release of bioactive molecules. However, the acidic microenvironment within these microparticles, as they degrade, has been reported to perturb the configuration of most encapsulated proteins. In addition, these polymer particles are also reported to suffer from unrealistically slow and incomplete release of proteins. To address these drawbacks, hollow PLGA microparticles are fabricated through a novel one‐step oil‐in‐water emulsion solvent evaporation technique, by capitalizing on the osmotic property of an osmogen. The effects of fabrication parameters on particle size and morphology, i.e., volume space of hollow cavity and shell thickness, are also studied. These hollow microparticles are subsequently loaded with bovine insulin microcrystals. It is shown that insulin release profiles can be tuned by simply changing the amount of osmogen in the formulation. At the same time, these hollow microparticles are shown to be effective in maintaining the bioactivity of the encapsulated protein.
The glucose oxidase and glucose mediated formation of amphipilic copolymers of N‐(ferrocenoylmethyl)acrylamide (NFMA) and N,N‐diethylacrylamide (DEA) in aqueous cyclodextrin solution is presented. Thereby, NFMA is not only a comonomer but also part of the redox initiation system. The obtained copolymers contain NFMA units between 1 and 10 mol%. The molecular masses of the copolymers are dependent on the ferrocene content, whereupon molecular weights between 38 000 and 71 000 g mol−1 are achieved.
New macromolecules such as dendrimers are increasingly needed to drive breakthroughs in diverse areas, for example, healthcare. Here, the authors report hybrid antimicrobial dendrimers synthesized by functionalizing organometallic dendrimers with quaternary ammonium groups or 2‐mercaptobenzothiazole. The functionalization tunes the glass transition temperature and antimicrobial activities of the dendrimers. Electron paramagnetic resonance spectroscopy reveals that the dendrimers form free radicals, which have significant implications for catalysis and biology. In vitro antimicrobial assays indicate that the dendrimers are potent antimicrobial agents with activity against multidrug‐resistant pathogens such as methicillin‐resistant Staphylococcus aureus and vancomycin‐resistant Enterococcus faecium as well as other microorganisms. The functionalization increases the activity, especially in the quaternary ammonium group‐functionalized dendrimers. Importantly, the activities are selective because human epidermal keratinocytes cells and BJ fibroblast cells exposed to the dendrimers are viable after 24 h.
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.
Producing meiosis‐competent germ cells (GCs) from embryonic stem cells (ESCs) is essential for developing advanced therapies for infertility. Here, a novel approach is presented for generation of GCs from ESCs. In this regard, microparticles (MPs) have been developed from alginate sulfate loaded with bone morphogenetic protein 4 (BMP4). The results here show that BMP4 release from alginate sulfate MPs is significantly retarded by the sulfated groups compared to neat alginate. Then, BMP4‐laden MPs are incorporated within the aggregates during differentiation of GCs from ESCs. It is observed that BMP4‐laden MPs increase GC differentiation from ESCs at least twofold compared to the conventional soluble delivery method. Interestingly, following meiosis induction, Dazl , an intrinsic factor that enables GCs to enter meiosis, and two essential meiosis genes (Stra8 and Smc1b ) are upregulated significantly in MP‐induced aggregates compared to aggregates, which are formed by the conventional method. Together, these data show that controlled delivery of BMP4 during ESC differentiation into GC establish meiosis‐competent GCs which can serve as an attractive GC source for reproductive medicine.
The strand material in extrusion‐based bioprinting determines the microenvironments of the embedded cells and the initial mechanical properties of the constructs. One unmet challenge is the combination of optimal biological and mechanical properties in bioprinted constructs. Here, a novel bioprinting method that utilizes core–shell cell‐laden strands with a mechanically robust shell and an extracellular matrix‐like core has been developed. Cells encapsulated in the strands demonstrate high cell viability and tissue‐like functions during cultivation. This process of bioprinting using core–shell strands with optimal biochemical and biomechanical properties represents a new strategy for fabricating functional human tissues and organs.
The human immunodeficiency virus (HIV) continues to be a global pandemic and there is an urgent need for innovative treatment. Immune cells represent a major target of virus infection, but are also therapeutic targets. Currently, no antiretroviral therapy targets macrophages, which function as portal of entry and as major long‐term deposit of HIV. It has been shown before that human macrophages efficiently internalize gold nanoparticles, a fact which might be used to target them with drug‐nanoparticle conjugates. Here, the authors use gold nanocarriers to facilitate delivery of stavudine, a widely used antiretroviral drug, to primary human macrophages. Using an ease‐of‐use coupling method, a striking potentiation of stavudine intake by macrophages using gold nanocarriers is shown. Further, the carriers induce a specific subtype of proinflammatory activation indicative for antiviral activity of macrophages, which suggests promising novel treatment options for HIV.
The ability to tune supramolecular properties such as size, morphology, or metabolic stability is of paramount importance in the field of supramolecular chemistry. Peptide amphiphiles (PAs) are a family of functional self‐assembling biomaterials that have garnered widespread attention due to their broad applicability in medicine. PAs are generally comprised of an amino acid sequence connected to lipid tail(s) allowing them to self‐assemble into supramolecular structures with diverse morphologies. Herein, this study describes the synthesis of a new class of polyamine‐based “hybrid” PAs (PPAs) as novel self‐assembling systems. The described molecules possess diverse polyamine head groups with the goal of tuning physicochemical properties. The findings indicate that small changes in the polyamine head groups result in altered PPA morphologies (nanofibers, micelles, nanoworms). The PPAs present a wide range of physicochemical characteristics, show superior resistance to aggregation, a diverse metabolic profile, and varied assembling kinetics. Most of the PPAs do not show toxicity in the human cells lines evaluated. The PPAs described herein hold promising potential as a safe and nontoxic option for drug delivery, targeting, and tissue engineering applications.
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.
Highly efficient functionalization and cross‐linking of polypeptides is achieved via tyrosine‐triazolinedione (TAD) conjugation chemistry. The feasibility of the reaction is demonstrated by the reaction of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) with tyrosine containing block copolymer poly(ethylene glycol)‐Tyr4 as well as a statistical copolymer of tyrosine and lysine (poly(Lys40‐st‐Tyr10)) prepared form N‐carboxyanhydride polymerization. Selective reaction of PTAD with the tyrosine units is obtained and verified by size exclusion chromatography and NMR spectroscopy. Moreover, two monofunctional and two difunctional TAD molecules are synthesized. It is found that their stability in the aqueous reaction media significantly varied. Under optimized reaction conditions selective functionalization and cross‐linking, yielding polypeptide hydrogels, can be achieved. TAD‐mediated conjugation can offer an interesting addition in the toolbox of selective (click‐like) polypeptide conjugation methodologies as it does not require functional non‐natural amino acids.
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.
A novel PEGylation polypeptide, poly(ethylene glycol)‐b‐poly(l ‐lysine)‐b‐poly(l ‐cysteine) (PEG‐PLL‐PCys) triblock copolymer is synthesized via the sequential ring‐opening polymerization of amino acid N‐carboxyanhydrides initiated by methoxypolyethylene glycol amine (mPEG‐NH2, M w is 2 kDa). Subsequently, the obtained polypeptide is partially conjugated with fluorocarbon chains via disulfide exchange reaction. PLL segment can condense plasmid DNA through an electrostatic force to form a complex core, PEG segment surrounding the complex like a corona can prevent the complex from precipitation and reduce the adsorption of serum, while PCys segment with fluorocarbon can enhance the cellular uptake and the stability of the formed polyplex micelles in physiological conditions. Experiment results exhibit that the fluorinated polypeptides have low cytotoxicity and good gene transfection efficiency even in the presence of 50% fetal bovine serum.
