Natural extracellular matrix provides a number of distinct advantages for engineering replacement orthopedic tissue due to its intrinsic functional properties. The goal of this study was to optimize ...a biologically derived scaffold for tendon tissue engineering using equine flexor digitorum superficialis tendons. We investigated changes in scaffold composition and ultrastructure in response to several mechanical, detergent and enzymatic decellularization protocols using microscopic techniques and a panel of biochemical assays to evaluate total protein, collagen, glycosaminoglycan, and deoxyribonucleic acid content. Biocompatibility was also assessed with static mesenchymal stem cell (MSC) culture. Implementation of a combination of freeze/thaw cycles, incubation in 2% sodium dodecyl sulfate (SDS), trypsinization, treatment with DNase-I, and ethanol sterilization produced a non-cytotoxic biomaterial free of appreciable residual cellular debris with no significant modification of biomechanical properties. These decellularized tendon scaffolds (DTS) are suitable for complex tissue engineering applications, as they provide a clean slate for cell culture while maintaining native three-dimensional architecture.
Drug targeting is an active area of research and nano-scaled drug delivery systems hold tremendous potential for the treatment of neoplasms. In this study, a novel cyclodextrin (CD)-based ...nanoparticle drug delivery system has been assembled and characterized for the therapy of folate receptor-positive FR(+) cancer. Water-soluble folic acid (FA)-conjugated CD carriers (FACDs) were successfully synthesized and their structures were confirmed by 1D/2D nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS), high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and circular dichroism. Drug complexes of adamatane (Ada) and cytotoxic doxorubicin (Dox) with FACD were readily obtained by mixed solvent precipitation. The average size of FACD-Ada-Dox was 1.5-2.5 nm. The host-guest association constant Ka was 1,639 M-1 as determined by induced circular dichroism and the hydrophilicity of the FACDs was greatly enhanced compared to unmodified CD. Cellular uptake and FR binding competitive experiments demonstrated an efficient and preferentially targeted delivery of Dox into FR-positive tumor cells and a sustained drug release profile was seen in vitro. The delivery of Dox into FR(+) cancer cells via endocytosis was observed by confocal microscopy and drug uptake of the targeted nanoparticles was 8-fold greater than that of non-targeted drug complexes. Our docking results suggest that FA, FACD and FACD-Ada-Dox could bind human hedgehog interacting protein that contains a FR domain. Mouse cardiomyocytes as well as fibroblast treated with FACD-Ada-Dox had significantly lower levels of reactive oxygen species, with increased content of glutathione and glutathione peroxidase activity, indicating a reduced potential for Dox-induced cardiotoxicity. These results indicate that the targeted drug complex possesses high drug association and sustained drug release properties with good biocompatibility and physiological stability. The novel FA-conjugated beta -CD based drug complex might be promising as an anti-tumor treatment for FR(+) cancer.
Silica nanotubes (SNTs) functionalized with magnetic and up-conversion luminescent (UCL) NaYF sub(4):Yb/Er/Gd nanocrystals (NCs) (denoted as MUCNCsatSNTs) have been prepared by single-nozzle ...electrospinning based on a phase separation effect without any templates. Monodisperse and hydrophilic cubic alpha -NaYF sub(4):Yb/Er/Gd NCs decorated with polyethyleneimine (PEI) were fabricated in a facile hydrothermal route. Then, the Gd super(3+)-doped alpha -NaYF sub(4):Yb/Er NCs were dispersed into the electrospinning precursor solution containing polyvinylpyrrolidone (PVP) and tetraethylorthosilicate (TEOS), followed by the preparation of precursor nanotubes viaelectrospinning process. Finally, after annealing at 600 degree C, pure MUCNCsatSNTs were obtained. The biocompatibility test on L929 fibroblast cells using MTT assay reveals low cytotoxicity of the composites. Doxorubicin hydrochloride (DOX), a typical anti-cancer drug, was introduced into MUCNCsatSNTs to evaluate the loading and sustained release behaviours. The composite carriers provide pH-dependent drug release behaviour owing to abundant Si-OH active bonds of silica and its interactions with DOX. The in vitrocytotoxicity and cell uptake behaviour of the MUCNCsatSNTs for HeLa cells were evaluated. For in vitromagnetic resonance imaging (MRI), the composites show the promising spin lattice relaxation time (T sub(1)) weighted effect and could potentially apply as a T sub(1)-positive contrast agent. In addition, the composites show near-infrared UC luminescence and were successfully applied in the bioimaging of HeLa cells. Considering the good biocompatibility, high drug releasing content and pH-dependent drug release of the materials, these magnetic and luminescent composite nanotubes have potential applications in drug sustained release and magnetic resonance/UC luminescence modality imaging.
Directed tissue self-assembly or bottom-up modular approach in tissue biofabrication is an attractive and potentially superior alternative to a classic top-down solid scaffold-based approach in ...tissue engineering. For example, rapidly emerging organ printing technology using self-assembling tissue spheroids as building blocks is enabling computer-aided robotic bioprinting of three-dimensional (3D) tissue constructs. However, achieving proper material properties while maintaining desirable geometry and shape of 3D bioprinted tissue engineered constructs using directed tissue self-assembly, is still a challenge. Proponents of directed tissue self-assembly see the solution of this problem in developing methods of accelerated tissue maturation and/or using sacrificial temporal supporting of removable hydrogels. In the meantime, there is a growing consensus that a third strategy based on the integration of a directed tissue self-assembly approach with a conventional solid scaffold-based approach could be a potential optimal solution. We hypothesise that tissue spheroids with avelcroARG-likea interlockable solid microscaffolds or simply alockyballsa could enable the rapid in vivo biofabrication of 3D tissue constructs at desirable material properties and high initial cell density. Recently, biocompatible and biodegradable photo-sensitive biomaterials could be fabricated at nanoscale resolution using two-photon polymerisation (2PP), a development rendering this technique with high potential to fabricate avelcroARG-likea interlockable microscaffolds. Here we report design studies, physical prototyping using 2PP and initial functional characterisation of interlockable solid microscaffolds or so-called alockyballsa. 2PP was used as a novel enabling platform technology for rapid bottom-up modular tissue biofabrication of interlockable constructs. The principle of lockable tissue spheroids fabricated using the described lockyballs as solid microscaffolds is characterised by attractive new functionalities such as lockability and tunable material properties of the engineered constructs. It is reasonable to predict that these building blocks create the basis for a development of a clinical in vivo rapid biofabrication approach and form part of recent promising emerging bioprinting technologies.
Durable and biocompatible magnetic scaffolds prepared by simple approaches are important for the development of tissue engineering. In this work, by freeze-drying method and without using any ...crosslinker, we successfully fabricated Fe
O
/chitosan magnetic scaffolds that belong to hard magnetic materials and are stable in physiological fluid. In vitro biocompatibility assay showed that mouse mesenchymal progenitor cells grow normally on the surface of the scaffolds. So these magnetic scaffolds have potentials to be used in tissue engineering as implants that independently direct drug targeting.
The antitumour effects of benzothiazoles are well documented, but they suffer from poor aqueous solubility and lipophilicity. Apoferritin (AFt) has been identified as a potential drug delivery ...vehicle due to its uniform size, biocompatibility, nontoxicity and its ability to load both hydrophobic and hydrophilic agents. Both 5F 203 and GW 610 were successfully encapsulated within AFt via the nanoreactor route, with 71 and 191 molecules per AFt, respectively. The encapsulation efficiency and drug loading of GW 610 are far superior to those of 5F 203. Encapsulation enhanced the potency of 5F 203 and GW 610 in the majority of sensitive cell lines tested, while retaining their selectivity. To improve solubility and increase encapsulation efficiency of GW 610, a series of GW 608 amino acid esters were synthesised. All GW 608-AAs showed enhanced encapsulation compared to GW 610. Increased polarity appeared to hinder encapsulation while a net positive charge increased encapsulation, with > 380 molecules of GW 608-Lys molecules per AFt cage. AFt-GW 608-Lys was found to more potent than AFt-GW 610 in 4/6 sensitive cell lines tested, and up to >3x more potent. The lysyl-amide conjugate of 5F 203, Phortress, was also encapsulated within AFt, with 130 molecules per AFt cage. This increased number of molecules per AFt cage led AFt-Phortress being more potent than AFt-5F 203 in 3/4 sensitive cell lines tested. Steady release of benzothiazoles from within AFt occurs over 12 hr at physiologically relevant pH, and is controlled by electrostatic interactions between the benzothiazole and the Aft. The formulations, AFt-Phortress and AFt-GW 608-Lys, which combine the potent and selective antitumour activity of parent benzothiazoles with biocompatibility of AFt delivery vehicle, present a viable putative anticancer therapy worthy of further preclinical development.
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