Chitosomes Loaded with Docetaxel as a Promising Drug Delivery System to Laryngeal Cancer Cells: An In Vitro Cytotoxic Study.

Current delivery of chemotherapy, either intra-venous or intra-arterial, remains suboptimal for patients with head and neck tumors. The free form of chemotherapy drugs, such as docetaxel, has non-specific tissue targeting and poor solubility in blood that deters treatment efficacy. Upon reaching the tumors, these drugs can also be easily washed away by the interstitial fluids. Liposomes have been used as nanocarriers to enhance docetaxel bioavailability. However, they are affected by potential interstitial dislodging due to insufficient intratumoral permeability and retention capabilities. Here, we developed and characterized docetaxel-loaded anionic nanoliposomes coated with a layer of mucoadhesive chitosan (chitosomes) for the application of chemotherapy drug delivery. The anionic liposomes were 99.4 ± 1.5 nm in diameter with a zeta potential of -26 ± 2.0 mV. The chitosan coating increased the liposome size to 120 ± 2.2 nm and the surface charge to 24.8 ± 2.6 mV. Chitosome formation was confirmed via FTIR spectroscopy and mucoadhesive analysis with anionic mucin dispersions. Blank liposomes and chitosomes showed no cytotoxic effect on human laryngeal stromal and cancer cells. Chitosomes were also internalized into the cytoplasm of human laryngeal cancer cells, indicating effective nanocarrier delivery. A higher cytotoxicity (p < 0.05) of docetaxel-loaded chitosomes towards human laryngeal cancer cells was observed compared to human stromal cells and control treatments. No hemolytic effect was observed on human red blood cells after a 3 h exposure, proving the proposed intra-arterial administration. Our in vitro results supported the potential of docetaxel-loaded chitosomes for locoregional chemotherapy delivery to laryngeal cancer cells.

Rapid Formation of Multicellular Spheroids in Boundary-Driven Acoustic Microstreams.

3D cell spheroid culture has emerged as a more faithful recreation of cell growth environment compared to conventional 2D culture, as it can maintain tissue structures, physicochemical characteristics, and cell phenotypes. The majority of current spheroid formation methods are limited to a physical agglomeration of the desired cell type, and then relying on cell capacity to secrete extracellular matrix to form coherent spheroids. Hence, apart from being time-consuming, their success in leading to functional spheroid formation is also cell-type dependent. In this study, a boundary-driven acoustic microstreaming tool is presented that can simultaneously congregate cells and generate sturdy cell clusters through incorporating a bioadhesive such as collagen for rapid production of spheroids. The optimized mixture of type I collagen (0.42 mg mL-1 ) and methylcellulose (0.4% w/v ) accelerates the coagulation of cell-matrix as fast as 10 s while avoiding their adhesion to the device, and thereby offering easy spheroid retrieval. The versatility of the platform is shown for the production of MDA-MB-231 and MCF-7 spheroids, multicellular spheroids, and composite spheroids made of cells and microparticles. The ability to produce densely packed spheroids embedded within a biomimetic extracellular matrix component, along with rapid formation and easy collection of spheroids render the proposed device a step in technology development required to realize potentials of 3D constructs such as building blocks for the emerging field of bottom-up tissue engineering.

Gold nanoparticle amplification strategies for multiplex SPRi-based immunosensing of human pancreatic islet hormones.

In this work, we demonstrate the potential use of SPRi for secretion-monitoring of pancreatic islets, small micro-organs that regulate glucose homeostasis in the body. In the islets, somatostatin works as a paracrine inhibitor of insulin and glucagon secretion. However, this inhibitory effect is lost in diabetic individuals and little is known about its contribution to the pathology of diabetes. Thus, the simultaneous detection of insulin, glucagon and somatostatin could help understand such communications. Previously, the authors introduced an SPRi biosensor to simultaneously monitor insulin, glucagon and somatostatin using an indirect competitive immunoassay. However, our sensor achieved a relatively high LOD for somatostatin detection (246 nM), the smallest of the three hormones. For this reason, the present work aimed to improve the performance of our SPRi biosensor using gold nanoparticles (GNPs) as a means of ensuring somatostatin detection from a small group of islets. Although GNP amplification is frequently reported in the literature for individual detection of analytes using SPR, studies regarding the optimal strategy in a multiplexed SPR setup are missing. Therefore, with the aim of finding the optimal GNP amplification strategies for multiplex sensing we compared three architectures: (1) GNPs immobilized on the sensor surface, (2) GNPs conjugated with primary antibodies (GNP-Ab1) and (3) GNPs conjugated with a secondary antibody (GNP-Ab2). Among these strategies an immunoassay using GNP-Ab2 conjugates was able to achieve multiplex detection of the three hormones without cross-reactivity and with 9-fold LOD improvement for insulin, 10-fold for glucagon and 200-fold for somatostatin when compared to the SPRi biosensor without GNPs. The present work denotes the first report of the simultaneous detection of such hormones with a sensitivity level comparable to ELISA assays, particularly for somatostatin.

Interfacial capacitance immunosensing using interdigitated electrodes: the effect of insulation/immobilization chemistry.

With the aim of improving the reproducibility of capacitive immunosensors, we performed a comparative study of four different insulating/immobilization chemistries. Each chemistry targeted different areas of an interdigitated electrode including an alkyl thiol monolayer on the electrode surface, an amino silane monolayer on the gaps between electrodes, and conformal coatings via passive adsorption of the probe and a spin-coated layer of poly(methyl methacrylate) (PMMA). We analyzed the dielectric properties of these chemistries by comparing their capacitive behavior through equivalent circuit modeling and correlate the observed behavior with their surface characteristics by using atomic force microscopy and finite element modeling. We found that surface binding events occurring in the interdigitated electrode gaps play a major role in the overall change in capacitance. This was confirmed via finite element modeling showing an increased electric field intensity in the electrode gaps by 14%, compared to directly above the electrodes. Among the investigated surface chemistries, PMMA conformal coating produced a smooth surface (Rq roughness = 0.21 ± 0.02 nm) providing the most reproducible and stable capacitance change (15.6 ± 0.4%) in response to specific antigen-antibody binding.

Multiplex Surface Plasmon Resonance Imaging-Based Biosensor for Human Pancreatic Islets Hormones Quantification.

Diabetes arises from secretory defects in vascularized micro-organs known as the islets of Langerhans. Recent studies indicated that furthering our understanding of the paracrine effect of somatostatin on glucose-induced insulin secretion could represent a novel therapeutic avenue for diabetes. While many research groups are interested in insulin and glucagon secretion, few are particularly focused on studying the paracrine interaction in islets' cells, and none on monitoring a secretory fingerprint that contemplates more than two hormones. Surface plasmon resonance imaging can achieve high-throughput and multiplexed biomolecule quantification, making it an ideal candidate for detection of multiple islet's secretion products if arrays of hormones can be properly implemented on the sensing surface. In this study, we introduced a multiplex surface plasmon resonance imaging-based biosensor for simultaneous quantification of insulin, glucagon, and somatostatin. Performing this multiplex biosensing of hormones was mainly the result of the design of an antifouling sensing surface comprised by a mixed self-assembly monolayer of CH3O-PEG-SH and 16-mercaptohexadecanoic acid, which allowed it to operate in a complex matrix such as an islet secretome. The limit of detection in multiplex mode was 1 nM for insulin, 4 nM for glucagon, and 246 nM for somatostatin with a total analysis time of 21 min per point, making our approach the first reporting a label-free and multiplex measurement of such a combination of human hormones. This biosensor holds the promise of providing us with a mean for the further understanding of the paracrine effect of somatostatin on glucose-induced insulin secretion and consequently help develop novel therapeutic agents for diabetes.

Monitoring of bacterial film formation and its breakdown with an angular-based surface plasmon resonance biosensor.

Bacterial biofilms are a leading cause of infection in health-care settings. Surface plasmon resonance (SPR) biosensors stand as valuable tools not only for the detection of biological entities and the characterisation of biomaterials but also as a suitable means to monitor bacterial film formation. This article reports on a proof-of-concept study for the use of an angular-based SPR biosensor for the monitoring of bacterial cell growth and biofilm formation and removal under the effect of different cleaning agents. The benefit of this custom-made SPR instrument is that it records simultaneously both the critical and resonant angles. This provides unique information on the growth of bacterial cells which is otherwise not obtainable with commonly used intensity-based SPR systems. The results clearly showed that a multilayer biofilm can be formed in 48 hours and the steps involved can be monitored in real-time with the SPR instrument through the measurement of the refractive index change and following the evolution in the shape of the SPR curve. The number, the depth and the sharpness of the reflection ripples varied as the film became thicker. Simulation results confirmed that the number of layers of bacteria affected the number of ripples at the critical angle. Real-time monitoring of the film breakdown with three cleaning agents indicated that bleach solution at 4.5% was the most effective in disrupting the biofilm from the gold sensor. Our overall findings suggest that the SPR biosensor with angular modulation presented in this article can perform real-time monitoring of biofilm formation and has the potential to be used as a platform to test the efficiency of disinfectants.

Noncovalently functionalized monolayer graphene for sensitivity enhancement of surface plasmon resonance immunosensors.

A highly efficient surface plasmon resonance (SPR) immunosensor is described using a functionalized single graphene layer on a thin gold film. The aim of this approach was two-fold: first, to amplify the SPR signal by growing graphene through chemical vapor deposition and, second, to control the immobilization of biotinylated cholera toxin antigen on copper coordinated nitrilotriacetic acid (NTA) using graphene as an ultrathin layer. The NTA groups were attached to graphene via pyrene derivatives implying π-π interactions. With this setup, an immunosensor for the specific antibody anticholera toxin with a detection limit of 4 pg mL(-1) was obtained. In parallel, NTA polypyrrole films of different thicknesses were electrogenerated on the gold sensing platform where the optimal electropolymerization conditions were determined. For this optimized polypyrrole-NTA setup, the simple presence of a graphene layer between the gold and polymer film led to a significant increase of the SPR signal.

Rapid and specific SPRi detection of L. pneumophila in complex environmental water samples.

Legionellosis is a very devastating disease worldwide mainly due to unpredictable outbreaks in man-made water systems. Developing a highly specific and sensitive rapid detection system that detects only metabolically active bacteria is a main priority for water quality assessment. We previously developed a versatile technique for sensitive and specific detection of synthetic RNA. In the present work, we further investigated the performance of the developed biosensor for detection of Legionella pneumophila in complex environmental samples, particularly those containing protozoa. The specificity and sensitivity of the detection system were verified using total RNA extracted from L. pneumophila in spiked water co-cultured with amoebae. We demonstrated that the expression level of ribosomal RNA (rRNA) is extremely dependent on the environmental conditions. The presence of amoebae with L. pneumophila, especially in nutrition-deprived samples, increased the amount of L. pneumophila 15-fold after 1 week as measured through the expression of 16s rRNA. Using the developed surface plasmon resonance imaging (SPRi) detection method, we were also able to successfully detect L. pneumophila within 3 h, both in the presence and absence of amoebae in the complex environmental samples obtained from a cooling water tower. These findings suggest that the developed biosensing system is a viable method for rapid, real-time and effective detection not only for L. pneumophila in environmental samples but also to assess the risk associated with the use of water contaminated with other pathogens.

The potential roles of nanobiomaterials in distraction osteogenesis.

Distraction osteogenesis (DO) technique is used worldwide to treat many orthopedic conditions. Although successful, one limitation of this technique is the extended period of fixators until the bone is consolidated. The application of growth factors (GFs) is one promising approach to accelerate bone regeneration during DO. Despite promising in vivo results, its use is still limited in the clinic. This is secondary to inherent limitations of these GFs. Therefore, a development of delivery systems that allow sustained sequential release is necessary. Nanoparticles and nanocomposites have prevailing properties that can overcome the limitations of the current delivery systems. In addition, their use can overcome the current challenges associated with the insufficient mechanical properties of scaffolds and suboptimal osteogenic differentiation of transplanted cells in the distraction gap. We discuss the clinical implications, and potential early applications of the nanoparticles and nanocomposites for developing new treatments to accelerate bone regeneration in DO.

SN-38 active loading in poly(lactic-co-glycolic acid) nanoparticles and assessment of their anticancer properties on COLO-205 human colon adenocarcinoma cells.

SN-38 is a highly effective drug against many cancers. The development of an optimal delivery system for SN-38 is extremely challenging due to its low solubility and labile lactone ring. Herein, SN-38 encapsulated in poly(D,L-lactide-co-glycolide) nanoparticles (NPs) is introduced to enhance its solubility, stability and cellular uptake. SN-38-loaded NPs prepared by spontaneous emulsification solvent diffusion (SESD) method had an average diameter of 310 nm, a zeta potential of -9.69 mV and a loading efficiency of 71%. They were able to protect the active lactone ring of SN-38 against inactivation under physiological condition. A colorectal adenocarcinoma cell line (COLO-205) was used to assess the NPs effects on cytotoxicity and cellular uptake. Result showed a significant decreased cell proliferation and cell apoptosis. These results suggest that these SN-38-loaded NPs can be an effective delivery system for the treatment of colon cancer and potentially for other types of cancers.

Therapeutics of the future: Navigating the pitfalls of extracellular vesicles research from an osteoarthritis perspective.

Extracellular vesicles have gained wide momentum as potential therapeutics for osteoarthritis, a highly prevalent chronic disease that still lacks an approved treatment. The membrane-bound vesicles are secreted by all cells carrying different cargos that can serve as both disease biomarkers and disease modifiers. Nonetheless, despite a significant peak in research regarding EVs as OA therapeutics, clinical implementation seems distant. In addition to scalability and standardization challenges, researchers often omit to focus on and consider the proper tropism of the vesicles, the practicality and relevance of their source, their low native therapeutic efficacy, and whether they address the disease as a whole. These considerations are necessary to better understand EVs in a clinical light and have been comprehensively discussed and ultimately summarized in this review into a conceptualized framework termed the nanodiamond concept. Future perspectives are also discussed, and alternatives are presented to address some of the challenges and concerns.

A landscape of recent advances in lipid nanoparticles and their translational potential for the treatment of solid tumors.

Lipid nanoparticles (LNPs) are biocompatible drug delivery systems that have found numerous applications in medicine. Their versatile nature enables the encapsulation and targeting of various types of medically relevant molecular cargo, including oligonucleotides, proteins, and small molecules for the treatment of diseases, such as cancer. Cancers that form solid tumors are particularly relevant for LNP-based therapeutics due to the enhanced permeation and retention effect that allows nanoparticles to accumulate within the tumor tissue. Additionally, LNPs can be formulated for both locoregional and systemic delivery depending on the tumor type and stage. To date, LNPs have been used extensively in the clinic to reduce systemic toxicity and improve outcomes in cancer patients by encapsulating chemotherapeutic drugs. Next-generation lipid nanoparticles are currently being developed to expand their use in gene therapy and immunotherapy, as well as to enable the co-encapsulation of multiple drugs in a single system. Other developments include the design of targeted LNPs to specific cells and tissues, and triggerable release systems to control cargo delivery at the tumor site. This review paper highlights recent developments in LNP drug delivery formulations and focuses on the treatment of solid tumors, while also discussing some of their current translational limitations and potential opportunities in the field.

Design of a universal biointerface for sensitive, selective, and multiplex detection of biomarkers using surface plasmon resonance imaging.

This paper reports on the sensitive, selective, and simultaneous detection of four protein biomarkers involved in metastasis of various cancers, namely Fas, angiopoietin-2 (Ang-2), human epidermal growth factor receptor 2 (HER2), and matrix metallopeptidase-9 (MMP-9) using an antibody-conjugated quantum dot (QD) chip and surface plasmon resonance imaging (SPRi) biosensors. Initially, a self-assembled monolayer film of l-cysteine, using glutaraldehyde as a linker and QDs as signal enhancement moieties, was employed to immobilize anti-Fas for the detection of Fas as a model protein in buffer. The biointerface was characterized using confocal microscopy, atomic force microscopy, and scanning electron microscopy to provide evidence of uniform surface coverage by the QDs. The SPRi signal was enhanced 100-fold to achieve a detection limit of 25 pg mL(-1) after applying biotinylated detection antibody-conjugate streptavidin-modified QDs. Secondly, this signal amplification strategy was applied to sequentially detect Fas, HER2, MMP-9, and Ang-2 at low concentrations on a protein-microprinted/gold-coated SPRi chip. The results showed the absence of cross-reactivity among these proteins and the feasibility of the approach for multiplex detection of biomarkers as required for the accurate diagnosis of various diseases.

Acoustofluidics - changing paradigm in tissue engineering, therapeutics development, and biosensing.

For more than 70 years, acoustic waves have been used to screen, diagnose, and treat patients in hundreds of medical devices. The biocompatible nature of acoustic waves, their non-invasive and contactless operation, and their compatibility with wide visualization techniques are just a few of the many features that lead to the clinical success of sound-powered devices. The development of microelectromechanical systems and fabrication technologies in the past two decades reignited the spark of acoustics in the discovery of unique microscale bio applications. Acoustofluidics, the combination of acoustic waves and fluid mechanics in the nano and micro-realm, allowed researchers to access high-resolution and controllable manipulation and sensing tools for particle separation, isolation and enrichment, patterning of cells and bioparticles, fluid handling, and point of care biosensing strategies. This versatility and attractiveness of acoustofluidics have led to the rapid expansion of platforms and methods, making it also challenging for users to select the best acoustic technology. Depending on the setup, acoustic devices can offer a diverse level of biocompatibility, throughput, versatility, and sensitivity, where each of these considerations can become the design priority based on the application. In this paper, we aim to overview the recent advancements of acoustofluidics in the multifaceted fields of regenerative medicine, therapeutic development, and diagnosis and provide researchers with the necessary information needed to choose the best-suited acoustic technology for their application. Moreover, the effect of acoustofluidic systems on phenotypic behavior of living organisms are investigated. The review starts with a brief explanation of acoustofluidic principles, the different working mechanisms, and the advantages or challenges of commonly used platforms based on the state-of-the-art design features of acoustofluidic technologies. Finally, we present an outlook of potential trends, the areas to be explored, and the challenges that need to be overcome in developing acoustofluidic platforms that can echo the clinical success of conventional ultrasound-based devices.

Bone-mimicking scaffold based on silk fibroin incorporated with hydroxyapatite and titanium oxide as enhanced osteo-conductive material for bone tissue formation: fabrication, characterization, properties, andin vitrotesting.

Bone-mimicking scaffolds based on silk fibroin (SF) mixed with hydroxyapatite nanoparticles (HA NPs) and titanium oxide (TiO2) nanoparticles were created as materials for bone formation. Six scaffold groups were fabricated: S1 (SF), S2 (Silk + (HA: TiO2; 100: 0)), S3 (Silk, (HA: TiO2; 70: 30)), S4 (Silk + (HA NPs: TiO2; 50: 50)), S5 (Silk + (HA: TiO2; 30: 70)), and S6 (Silk + (HA NPs: TiO2; 0:100)). Scaffolds were characterized for molecular formation, structure, and morphology by Fourier transform infrared spectroscopy, element analysis, and X-ray diffraction. They were tested for physical swelling and compressive modulus. Scaffolds were cultured with MC3T3 and testedin vitroto evaluate their biological performance. The results showed that scaffolds with HA and TiO2demonstrated molecular interaction via amide I and phosphate groups. These scaffolds had smaller pore sizes than those without HA and TiO2. They showed more swelling and higher compressive modulus than the scaffolds without HA and TiO2. They exhibited better biological performance: cell adhesion, viability, proliferation, alkaline phosphatase activity, and calcium content than the scaffolds without HA and TiO2. Their porous walls acted as templates for cell aggregation and supported synthesis of calcium secreted from cells. S3 were the most suitable scaffolds. With their enhanced osteo-conductive function, they are promising for bone augmentation for oral and maxillofacial surgery.

The Diamond Concept Enigma: Recent Trends of Its Implementation in Cross-linked Chitosan-Based Scaffolds for Bone Tissue Engineering.

An increasing number of publications over the past ten years have focused on the development of chitosan-based cross-linked scaffolds to regenerate bone tissue. The design of biomaterials for bone tissue engineering applications relies heavily on the ideals set forth by a polytherapy approach called the "Diamond Concept". This methodology takes into consideration the mechanical environment, scaffold properties, osteogenic and angiogenic potential of cells, and benefits of osteoinductive mediator encapsulation. The following review presents a comprehensive summarization of recent trends in chitosan-based cross-linked scaffold development within the scope of the Diamond Concept, particularly for nonload-bearing bone repair. A standardized methodology for material characterization, along with assessment of in vitro and in vivo potential for bone regeneration, is presented based on approaches in the literature, and future directions of the field are discussed.

Sonoprinting nanoparticles on cellular spheroids via surface acoustic waves for enhanced nanotherapeutics delivery.

Nanotherapeutics, on their path to the target tissues, face numerous physicochemical hindrances that affect their therapeutic efficacy. Physical barriers become more pronounced in pathological tissues, such as solid tumors, where they limit the penetration of nanocarriers into deeper regions, thereby preventing the efficient delivery of drug cargo. To address this challenge, we introduce a novel approach that employs surface acoustic wave (SAW) technology to sonoprint and enhance the delivery of nanoparticles onto and into cell spheroids. Our SAW platform is designed to generate focused and unidirectional acoustic waves for creating vigorous acoustic streaming while promoting Bjerknes forces. The effect of SAW excitation on cell viability, as well as the accumulation and penetration of nanoparticles on human breast cancer (MCF 7) and mouse melanoma (YUMM 1.7) cell spheroids were investigated. The high frequency, low input voltage, and contact-free nature of the proposed SAW system ensured over 92% cell viability for both cell lines after SAW exposure. SAW sonoprinting enhanced the accumulation of 100 nm polystyrene particles on the periphery of the spheroids to near four-fold, while the penetration of nanoparticles into the core regions of the spheroids was improved up to three times. To demonstrate the effectiveness of our SAW platform on the efficacy of nanotherapeutics, the platform was used to deliver nanoliposomes encapsulated with the anti-cancer metal compound copper diethyldithiocarbamate (CuET) to MCF 7 and YUMM 1.7 cell spheroids. A three-fold increase in the cytotoxic activity of the drug was observed in spheroids under the effect of SAW, compared to controls. The capacity of SAW-based devices to be manufactured as minuscule wearable patches can offer highly controllable, localized, and continuous acoustic waves to enhance drug delivery efficiency to target tissues.

Renewable Human Cell Model for Type 1 Diabetes Research: EndoC-ßH5/HUVEC Coculture Spheroids.

In vitro drug screening for type 1 diabetes therapies has largely been conducted on human organ donor islets for proof of efficacy. While native islets are the ultimate target of these drugs (either in situ or for transplantation), significant benefit can be difficult to ascertain due to the highly heterogeneous nature of individual donors and the overall scarcity of human islets for research. We present an in vitro coculture model based on immortalized insulin-producing beta-cell lines with human endothelial cells in 3D spheroids that aims to recapitulate the islet morphology in an effort towards developing a standardized cell model for in vitro diabetes research. Human insulin-producing immortalized EndoC-ßH5 cells are cocultured with human endothelial cells in varying ratios to evaluate 3D cell culture models for type 1 diabetes research. Insulin secretion, metabolic activity, live cell fluorescence staining, and gene expression assays were used to compare the viability and functionality of spheroids composed of 100% beta-cells, 1 : 1 beta-cell/endothelial, and 1 : 3 beta-cell/endothelial. Monoculture and ßH5/HUVEC cocultures formed compact spheroids within 7 days, with average diameter ~140 µm. This pilot study indicated that stimulated insulin release from 0 to 20 mM glucose increased from ~8-fold for monoculture and 1 : 1 coculture spheroids to over 20-fold for 1 : 3 EndoC-ßH5/HUVEC spheroids. Metabolic activity was also ~12% higher in the 1 : 3 EndoC-ßH5/HUVEC group compared to other groups. Stimulating monoculture beta-cell spheroids with 20 mM glucose +1 µg/mL glycine-modified INGAP-P increased the insulin stimulation index ~2-fold compared to glucose alone. Considering their availability and consistent phenotype, EndoC-ßH5-based spheroids present a useful 3D cell model for in vitro testing and drug screening applications.

A 6-bromoindirubin-3'-oxime incorporated chitosan-based hydrogel scaffold for potential osteogenic differentiation: Investigation of material properties in vitro.

Effective treatments for critical size bone defects remain challenging. 6-Bromoindirubin-3'-Oxime (BIO), a glycogen synthase kinase 3ß inhibitor, is a promising alternative for treatment of these defects since it aids in promoting osteogenic differentiation. In this study, BIO is incorporated into a new formulation of the guanosine diphosphate cross-linked chitosan scaffold to promote osteogenic differentiation. BIO incorporation was confirmed with 13C NMR through a novel concentration dependent peak around 41 ppm. The rapid gelation rate was maintained along with the internal structure's stability. The 10 µM BIO dose supported the control scaffold's microstructure demonstrating a suitable porosity and a low closed pore percentage. While pore sizes of BIO incorporated scaffolds were slightly smaller, pore heterogeneity was maintained. A proof-of-concept study with C2C12 cells suggested a dose-dependent response of BIO on early stages of osteogenic differentiation within the scaffold. These results support future work to examine BIO's role on osteogenic differentiation and biomineralization of encapsulated cells in the scaffold for bone regeneration.

Development and mechanical characterization of decellularized scaffolds for an active aortic graft.

Decellularized porcine aortas are proposed as scaffolds for revolutionary active aortic grafts. A change in the static and dynamic mechanical properties, associated with the microstructure of elastin and collagen fibers, corresponds to alteration in the cyclic expansion and perfusion, in addition to possible graft damage. Therefore, the present study thoroughly investigates the mechanical response of the decellularized scaffolds of human and porcine origin to static and dynamic mechanical loads. The responses of the native human and porcine aortas are also compared; this is unavailable in the literature. Because the aorta is subjected to pulsatile blood pressure, dynamical responses to cyclic loads and their associated viscoelastic properties are particularly relevant for advanced graft design. In parallel, this study examines the microstructure of the decellularized aorta. The resulting data are compared to the analogous data obtained for the native human and porcine tissues. The results indicate that by using an optimized decellularization protocol - based on sodium dodecyl sulfate (SDS) and DNase - that minimizes mechanical and structural changes of the tissue, layered scaffolds with static and dynamic properties very similar to natural human aortas are obtained. In particular, a decellularized porcine aorta is non-inferior to a decellularized human aorta. STATEMENT OF SIGNIFICANCE: About 55,000 patients undergo abdominal aortic aneurysm repair annually in the USA. The currently implanted grafts present a large mechanical mismatch with the native tissue. This increases the pulsatile nature of the blood flow with negative consequences to the organ perfusion. For this reason, biomimetic and mechanically compatible grafts for aortic repair are urgently needed and they can be obtained through tissue engineering. In this study, scaffolds from porcine and human aortas are obtained from an optimized decellularization protocol. They are accurately compared to the native tissue and present the ideal static and dynamic mechanical properties for developing innovative aortic grafts.