Antimicrobial Peptides Secreted From Human Cryopreserved Viable Amniotic Membrane Contribute to its Antibacterial Activity.

Chronic wounds remain a large problem in the field of medicine and are often associated with risk of infection and amputation. Recently, a commercially available human cryopreserved viable amniotic membrane (hCVAM) has been shown to effectively promote wound closure and reduce wound-related infections. A sprevious study indicates that hCVAM can inhibit the growth of bacteria associated with chronic wounds.

The control of stem cell morphology and differentiation using three-dimensional printed scaffold architecture.

In this work, we investigated the interactions of human mesenchymal stem cells (hMSCs) with three-dimensional (3D) printed scaffolds displaying different scaffold architectures. Pressure-assisted microsyringe system was used to fabricate scaffolds with square (SQR), hexagonal (HEX), and octagonal (OCT) architectures defined by various degrees of curvatures. OCT represents the highest degree of curvature followed by HEX, and SQR is composed of linear struts without curvature.

Topical Delivery of Immunosuppression to Prolong Xenogeneic and Allogeneic Split-Thickness Skin Graft Survival.

Cadaveric skin allograft is the current standard of treatment for temporary coverage of large burn wounds. Porcine xenografts are viable alternatives but undergo α-1,3-galactose (Gal)-mediated hyperacute rejection and are lost by post-operative day (POD) 3 because of naturally occurring antibodies to Gal in primate recipients. Using baboons, we previously demonstrated that xenografts from GalT-KO swine (lacking Gal) provided wound coverage comparable with allografts with systemic immunosuppression.

Enhancement of plasma protein adsorption and osteogenesis of hMSCs by functionalized siloxane coatings for titanium implants.

A series of sol-gel derived silicon based coatings were developed to improve the osseointegration of commercial titanium dental implants. The osseointegration starts with a positive interaction between the implant surface and surrounding tissues, which is facilitated by the adsorption of plasma proteins onto the biomaterial surface immediately after implantation. It is likely that the enhancement of protein adsorption to titanium implants leads to a better implant/tissue integration.

Cell type-specific extracellular matrix guided the differentiation of human mesenchymal stem cells in 3D polymeric scaffolds.

The tissue microenvironment has profound effects on tissue-specific regeneration. The 3-dimensional extracellular matrix (ECM) niche influences the linage-specific differentiation of stem cells in tissue. To understand how ECM guides tissue-specific regeneration, we established a series of 3D composite scaffolds containing ECMs derived from different primary cells isolated from a single animal species and assessed their impact on the differentiation of human mesenchymal stem cells (hMSCs).

Antibiotic loaded microspheres as antimicrobial delivery systems for medical applications.

In this paper, we present the preparation and antibiotic loading of polymeric microspheres, composed of copolymers derived from fatty acid/amino acid components, as new polymeric platforms for antibiotic delivery systems. New polymeric materials were used to prepare microspheres with and without immobilized model antibiotics (streptomycin, chloramphenicol and amphotericin B) by a W/O/W double-emulsion/solvent evaporation method, in which chloroform and poly(vinyl alcohol) are used as the solvent and emulsifier, respectively. The antimicrobial activity of the microspheres was tested against Gram-positive S.

Dual-Component Gelatinous Peptide/Reactive Oligomer Formulations as Conduit Material and Luminal Filler for Peripheral Nerve Regeneration.

Toward the next generation of nerve guidance conduits (NGCs), novel biomaterials and functionalization concepts are required to address clinical demands in peripheral nerve regeneration (PNR). As a biological polymer with bioactive motifs, gelatinous peptides are promising building blocks. In combination with an anhydride-containing oligomer, a dual-component hydrogel system (cGEL) was established.

Development of hybrid scaffolds with natural extracellular matrix deposited within synthetic polymeric fibers.

A major challenge of tissue engineering is to generate materials that combine bioactivity with stability in a form that captures the robust nature of native tissues. Here we describe a procedure to fabricate a novel hybrid extracellular matrix (ECM)-synthetic scaffold biomaterial by cell-mediated deposition of ECM within an electrospun fiber mat. Synthetic polymer fiber mats were fabricated using poly(desamino tyrosyl-tyrosine carbonate) (PDTEC) co-spun with poly(ethylene glycol) (PEG) used as a sacrificial polymer.

Structure and thermal transitions in a biomedically relevant liquid crystalline poly(ester amide).

There is still a need to develop bioresorbable polymers with high strength and high modulus for load-bearing biomedical applications. Here we investigate the liquid crystalline structural features of poly(desaminotyrosyl-tyrosine dodecyl dodecanedioate), poly(DTD DD), a new bioresorbable poly(ester amide) that is currently studied as a slow-degrading implantable biomaterial for load bearing applications. Thermally induced structural changes in poly(DTD DD) were studied using simultaneously differential scanning calorimetry (DSC) and X-ray scattering.

A suspended carbon fiber culture to model myelination by human Schwann cells.

Understanding of myelination/remyelination process is essential to guide tissue engineering for nerve regeneration. In vitro models currently used are limited to cell population studies and cannot easily identify individual cell contribution to the process. We established a novel model to study the contribution of human Schwann cells to the myelination process.

Optimization of Polymer-ECM Composite Scaffolds for Tissue Engineering: Effect of Cells and Culture Conditions on Polymeric Nanofiber Mats.

The design of composite tissue scaffolds containing an extracellular matrix (ECM) and synthetic polymer fibers is a new approach to create bioactive scaffolds that can enhance cell function. Currently, studies investigating the effects of ECM-deposition and decellularization on polymer degradation are still lacking, as are data on optimizing the stability of the ECM-containing composite scaffolds during prolonged cell culture. In this study, we develop fibrous scaffolds using three polymer compositions, representing slow (E0000), medium (E0500), and fast (E1000) degrading materials, to investigate the stability, degradation, and mechanics of the scaffolds during ECM deposition and decellularization, and during the complete cellularization-decell-recell cycle.

High-content image informatics of the structural nuclear protein NuMA parses trajectories for stem/progenitor cell lineages and oncogenic transformation.

Stem and progenitor cells that exhibit significant regenerative potential and critical roles in cancer initiation and progression remain difficult to characterize. Cell fates are determined by reciprocal signaling between the cell microenvironment and the nucleus; hence parameters derived from nuclear remodeling are ideal candidates for stem/progenitor cell characterization. Here we applied high-content, single cell analysis of nuclear shape and organization to examine stem and progenitor cells destined to distinct differentiation endpoints, yet undistinguishable by conventional methods.

Designing Biomaterials for 3D Printing.

Three-dimensional (3D) printing is becoming an increasingly common technique to fabricate scaffolds and devices for tissue engineering applications. This is due to the potential of 3D printing to provide patient-specific designs, high structural complexity, rapid on-demand fabrication at a low-cost. One of the major bottlenecks that limits the widespread acceptance of 3D printing in biomanufacturing is the lack of diversity in "biomaterial inks".

Immediate tangential excision accelerates wound closure but does not reduce scarring of mid-dermal porcine burns.

Current evidence supports the use of excision to remove eschar from deep dermal and full-thickness burns. However, the role of excision of mid-dermal burns remains unclear. This study aimed to develop a porcine model that could produce reproducible middermal thermal burns that undergo tangential excision; and investigate the effects of immediate tangential excision (30 minutes postburn) on healing and scarring.

Off-Target Effect of Sildenafil on Postsurgical Erectile Dysfunction: Alternate Pathways and Localized Delivery System.

Introduction: There is no consensus on the best oral phosphodiesterase type 5 inhibitor (PDE5I) for patients undergoing penile rehabilitation after surgical nerve injury.

Aim: To determine the mechanism of PDE5I on cultured neuronal cells and the effectiveness of local drug delivery using nanospheres (NSPs) to sites of nerve injury in a rat model of bilateral cavernous nerve injury (BCNI).

Methods: The effects of sildenafil, tadalafil, and vardenafil on cyclic adenosine monophosphate, cyclic guanosine monophosphate, and cell survival after exposure to hypoxia and HO were measured in PC12, SH-SY5Y, and NTERA-2 (NT2) cell cultures.

Polymeric nanospheres for topical delivery of vitamin D3.

This study investigates the potential application of polymeric nanospheres (known as TyroSpheres) as a formulation carrier for topical delivery of cholecalciferol (i.e., Vitamin D3, VD3) with the goal to improve the skin delivery and stability of VD3.

Dual-component collagenous peptide/reactive oligomer hydrogels as potential nerve guidance materials - from characterization to functionalization.

Toward a new generation of improved nerve guidance conduits (NGCs), novel biomaterials are required to address pressing clinical shortcomings in peripheral nerve regeneration (PNR) and to promote biological performance. A dual-component hydrogel system formed by cross-linking reaction between maleic anhydride groups in an oligomeric building block for cross-linking of free amine functionalities in partially hydrolyzed collagen is formulated for continuous processing and NGC fabrication. The influence of the gelation base is optimized for processing from a double syringe delivery system with a static mixer.

Profiling stem cell states in three-dimensional biomaterial niches using high content image informatics.

Unlabelled: A predictive framework for the evolution of stem cell biology in 3-D is currently lacking. In this study we propose deep image informatics of the nuclear biology of stem cells to elucidate how 3-D biomaterials steer stem cell lineage phenotypes. The approach is based on high content imaging informatics to capture minute variations in the 3-D spatial organization of splicing factor SC-35 in the nucleoplasm as a marker to classify emergent cell phenotypes of human mesenchymal stem cells (hMSCs).

Mitochondria-Targeted Hydroxyapatite Nanoparticles for Selective Growth Inhibition of Lung Cancer in Vitro and in Vivo.

Lung cancer is the leading cause of cancer-related mortality worldwide. Most patients have metastases at the time of diagnosis, thus demanding development of more effective and specific agents. In this study, the specific anticancer effect of hydroxyapatite nanoparticles (HAPNs) to human lung cancer cells (A549) and the underlying mechanisms were investigated, using normal bronchial epithelial cells (16HBE) as the control.

Negative Outcomes of Poly(l-Lactic Acid) Fiber-Reinforced Scaffolds in an Ovine Total Meniscus Replacement Model.

Our objective was to test the efficacy of collagen-hyaluronan scaffolds reinforced with poly(l-lactic acid) (PLLA) fibers in an ovine total meniscus replacement model. Scaffolds were implanted into 9 sheep (n = 1 at 8 weeks, n = 2 at 16 weeks, n = 3 at both 24, 32 weeks) following total medial meniscectomy. From 16 weeks on, explants were characterized by confined compression creep, histological, and biochemical analyses.

Mandibular Jaw Bone Regeneration Using Human Dental Cell-Seeded Tyrosine-Derived Polycarbonate Scaffolds.

Here we present a new model for alveolar jaw bone regeneration, which uses human dental pulp cells (hDPCs) combined with tyrosine-derived polycarbonate polymer scaffolds [E1001(1k)] containing beta-tricalcium phosphate (β-TCP) [E1001(1k)/β-TCP]. E1001(1k)/β-TCP scaffolds (5 mm diameter × 1 mm thickness) were fabricated to fit a 5 mm rat mandibular ramus critical bone defect. Five experimental groups were examined in this study: (1) E1001(1k)/β-TCP scaffolds seeded with a high density of hDPCs, 5.

Bio-inspired strategies for designing antifouling biomaterials.

Contamination of biomedical devices in a biological medium, biofouling, is a major cause of infection and is entirely avoidable. This mini-review will coherently present the broad range of antifouling strategies, germicidal, preventive and cleaning using one or more of biological, chemical and physical techniques. These techniques will be discussed from the point of view of their ability to inhibit protein adsorption, usually the first step that eventually leads to fouling.

Developing a Suitable Model for Water Uptake for Biodegradable Polymers Using Small Training Sets.

Prediction of the dynamic properties of water uptake across polymer libraries can accelerate polymer selection for a specific application. We first built semiempirical models using Artificial Neural Networks and all water uptake data, as individual input. These models give very good correlations (R (2) > 0.

Competitive Adsorption of Plasma Proteins Using a Quartz Crystal Microbalance.

Proteins that get adsorbed onto the surfaces of biomaterials immediately upon their implantation mediate the interactions between the material and the environment. This process, in which proteins in a complex mixture compete for adsorption sites on the surface, is determined by the physicochemical interactions at the interface. Competitive adsorption of bovine serum albumin (BSA), fibronectin (Fn), and collagen type I (Col I), sequentially and from mixtures, was investigated so as to understand the performances of different surfaces used in biomedical applications.