Comparison of hydroxyapatite and honeycomb micro-structure in bone tissue engineering using electrospun beads-on-string fibers.

Thick honeycomb-like electrospun scaffold with nanoparticles of hydroxyapatite (nHA) recently demonstrated its potential to promote proliferation and differentiation of a murine embryonic cell line (C3H10T1/2) to osteoblasts. In order to distinguish the respective effects of the structure and the composition on cell differentiation, beads-on-string fibers were used to manufacture thick honeycomb-like scaffolds without nHA. Mechanical and biological impacts of those beads-on string fibers were evaluated.

Enhancing cellular affinity for skin disorders: Electrospun polyurethane/collagen nanofiber mats coated with phytoceramides.

Although the use of thermoplastic polyurethane (Tpu) nanofiber mats as wound dressings is of great interest due to their mechanical properties, they are hindered by their poor wettability and bioavailability. In this study, we aimed to improve the cellular affinity of Tpu nanofiber mats for skin disorders by incorporating extracted collagen (Col) from tendons and physically mixed with a layer of phytoceramides (Phyto) to produce TpuCol@X-Phyto mats in which the weight % of Phyto relatively to the weight of the solution was X = 0.5, 1.

Smart chitosan nanogel for targeted doxorubicin delivery, ensuring precise release, and minimizing side effects in Ehrlich ascites carcinoma-bearing mice.

In recent decades, bio-polymeric nanogels have become a forefront in medical research as innovative in-vivo drug carriers. This study introduces a pH-sensitive chitosan nanoparticles/P(N-Isopropylacrylamide-co-Acrylic acid) nanogel (CSNPs/P(NIPAm-co-AAc)), making significant advancements. The nanogel effectively encapsulated doxorubicin hydrochloride (Dx.

Highly Structured 3D Electrospun Conical Scaffold: A Tool for Dental Pulp Regeneration.

New procedures envisioned for dental pulp regeneration after pulpectomy include cell homing strategy. It involves host endogenous stem cell recruitment and activation. To meet this cell-free approach, we need to design a relevant scaffold to support cell migration from tissues surrounding the dental root canal.

Polymer-free cyclodextrin and natural polymer-cyclodextrin electrospun nanofibers: A comprehensive review on current applications and future perspectives.

The present review discusses the use of cyclodextrins and their derivatives to prepare electrospun nanofibers with specific features. Cyclodextrins, owing to their unique capability to form inclusion complexes with hydrophobic and volatile molecules, can indeed facilitate the encapsulation of bioactive compounds in electrospun nanofibers allowing fast-dissolving products for food, biomedical, and pharmaceutical purposes, filtering materials for wastewater and air purification, as well as a variety of other technological applications. Additionally, cyclodextrins can improve the processability of naturally occurring biopolymers helping the fabrication of "green" materials with a strong industrial relevance.

Suturable elastomeric tubular grafts with patterned porosity for rapid vascularization of 3D constructs.

Vascularization is considered to be one of the key challenges in engineering functional 3D tissues. Engineering suturable vascular grafts containing pores with diameter of several tens of microns in tissue engineered constructs may provide an instantaneous blood perfusion through the grafts improving cell infiltration and thus, allowing rapid vascularization and vascular branching. The aim of this work was to develop suturable tubular scaffolds to be integrated in biofabricated constructs, enabling the direct connection of the biofabricated construct with the host blood stream, providing an immediate blood flow inside the construct.

Design of Functional Electrospun Scaffolds Based on Poly(glycerol sebacate) Elastomer and Poly(lactic acid) for Cardiac Tissue Engineering.

Many works focus on the use of polyesters such as poly(lactic acid) (PLA) to produce nanofibrous scaffolds for cardiac tissue engineering. However, such scaffolds are hydrophobic and difficult to functionalize. Here, we show that adding 30% of poly(glycerol sebacate) (PGS) elastomer within PLA leads to PLA:PGS scaffolds with improved biological properties, depending on the processing parameters.

The combination of a poly-caprolactone/nano-hydroxyapatite honeycomb scaffold and mesenchymal stem cells promotes bone regeneration in rat calvarial defects.

Bone tissue engineering goes beyond the limitations of conventional methods of treating bone loss, such as autograft-induced morbidity and a lack of integration for large grafts. Novel biomimicry approaches (using three-dimensional [3D] electrospinning and printing techniques) have been designed to offer the most appropriate environment for cells and thus promote bone regeneration. In the present study, we assessed the bone regeneration properties of a composite 3D honeycomb structure from the electrostatic template-assisted deposition process by an alternate deposition of electrospun polycaprolactone (PCL) nanofibers and electrosprayed hydroxyapatite nanoparticles (nHA) on a honeycomb micropatterned substrate.

A multi-layered nerve guidance conduit design adapted to facilitate surgical implantation.

Background And Aims: The gold standard procedure after a severe nerve injury is the nerve autograft, yet this technique has drawbacks. In recent years, progress has been made in the development of artificial nerve guides to replace the autograft, but no device has been able to demonstrate superiority. The present study introduces an adaptable foundation design for peripheral nerve regeneration.

Electrospinning in water and in situ crosslinking of hyaluronic acid / cyclodextrin nanofibers: Towards wound dressing with controlled drug release.

Hyaluronic acid (HA) is widely investigated due to its high potential for wound dressing applications. The fabrication of biomimetic HA-based scaffolds by electrospinning is thus extensively studied. However, HA is often dissolved in toxic organic solvents to allow the efficient production of electrospun nanofibers.

Poly(ε-caprolactone)/Hydroxyapatite 3D Honeycomb Scaffolds for a Cellular Microenvironment Adapted to Maxillofacial Bone Reconstruction.

The elaboration of biomimetic materials inspired from the specific structure of native bone is one the main goal of tissue engineering approaches. To offer the most appropriate environment for bone reconstruction, we combined electrospinning and electrospraying to elaborate an innovative scaffold composed of alternating layers of polycaprolactone (PCL) and hydroxyapatite (HA). In our approach, the electrospun PCL was shaped into a honeycomb-like structure with an inner diameter of 160 μm, capable of providing bone cells with a 3D environment while ensuring the material biomechanical strength.

Polymer-free electrospinning of tannic acid and cross-linking in water for hybrid supramolecular nanofibres.

Electrospinning is the process of choice allowing the preparation of nanofibrous materials from a solution usually based on a high molar mass polymer. The solution must bring enough chain entanglements to avoid any breaking or Rayleigh instability of the electrospun jet resulting thus in the deposition of a continuous and regular solid nanofibre. It has been however shown that some few non-polymeric molecules can be electrospun without using a carrier polymer.

Sampling the structure and chemical order in assemblies of ferromagnetic nanoparticles by nuclear magnetic resonance.

Assemblies of nanoparticles are studied in many research fields from physics to medicine. However, as it is often difficult to produce mono-dispersed particles, investigating the key parameters enhancing their efficiency is blurred by wide size distributions. Indeed, near-field methods analyse a part of the sample that might not be representative of the full size distribution and macroscopic methods give average information including all particle sizes.

Star-pseudopolyrotaxane organized in nanoplatelets for poly(ε-caprolactone)-based nanofibrous scaffolds with enhanced surface reactivity.

Herein, it is demonstrated that star pseudopolyrotaxanes (star-pPRs) obtained from the inclusion complexation of α-cyclodextrin (CD) and four-branched star poly(ε-caprolactone) (star-PCL) organize into nanoplatelets in dimethyl sulfoxide at 35 °C. This peculiar property, not observed for linear pseudopolyrotaxanes, allows the processing of star-pPRs while preserving their supramolecular assembly. Thus, original PCL:star-pPR core:shell nanofibers are elaborated by coaxial electrospinning.

Electrospun honeycomb as nests for controlled osteoblast spatial organization.

Honeycomb nanofibrous scaffolds were elaborated by electrospinning onto micro-patterned collectors either with poly(ϵ-caprolactone) (PCL) or poly(D, L-lactic acid) (PLA). The unimodal distribution of fiber diameters, observed for PLA, led to relatively flat scaffolds; on the other hand, the bimodal distribution of PCL fiber diameters significantly increased the relief of the scaffolds' patterns due to the preferential deposition of the thick fiber portions on the walls of the collector's patterns via preferential electrostatic interaction. Finally, a biological evaluation demonstrated the effect of the scaffolds' relief on the spatial organization of MG63 osteoblast-like cells.

Differentiation of human adipose-derived stem cells seeded on mineralized electrospun co-axial poly(ε-caprolactone) (PCL)/gelatin nanofibers.

Mineralized poly(ε-caprolactone)/gelatin core-shell nanofibers were prepared via co-axial electrospinning and subsequent incubation in biomimetic simulated body fluid containing ten times the calcium and phosphate ion concentrations found in human blood plasma. The deposition of calcium phosphate on the nanofiber surfaces was investigated through scanning electronic microscopy and X-ray diffraction. Energy dispersive spectroscopy results indicated that calcium-deficient hydroxyapatite had grown on the fibers.

Simultaneous electrospinning and electrospraying: a straightforward approach for fabricating hierarchically structured composite membranes.

We present here for the first time a simple method for micropatterning nonwoven composite membranes. The approach is based on the simultaneous electrospraying of microparticles and electrospinning of nanofibers from different polymer solution feeds (polyethylene glycol and poly(D,L-lactide)) on a common support. The mechanism of self-organization between fibers and particles into hierarchical honeycomb-like structures, as well as the evolution of the later as a function of the thickness of the composite, is investigated.

Osteogenetic properties of electrospun nanofibrous PCL scaffolds equipped with chitosan-based nanoreservoirs of growth factors.

Bioactive implants intended for rapid, robust, and durable bone tissue regeneration are presented. The implants are based on nanofibrous 3D-scaffolds of bioresorbable poly-ϵ-caprolactone mimicking the fibrillar architecture of bone matrix. Layer-by-layer nanoimmobilization of the growth factor BMP-2 in association with chitosan (CHI) or poly-L-lysine over the nanofibers is described.

Self-construction of supramolecular polyrotaxane films by an electrotriggered morphogen-driven process.

The design of films using a one-pot process has recently attracted increasing interest in the field of polymer thin film formation. Herein we describe the preparation of one-pot supramolecular polyrotaxane (PRX) films using the morphogen-driven self-construction process. This one-pot buildup strategy where the film growth is triggered by the electrochemical formation and diffusion of a catalyst in close vicinity of the substrate has recently been introduced by our group.

Electrospun nanofibrous 3D scaffold for bone tissue engineering.

Tissue engineering aims at developing functional substitutes for damaged tissues by mimicking natural tissues. In particular, tissue engineering for bone regeneration enables healing of some bone diseases. Thus, several methods have been developed in order to produce implantable biomaterial structures that imitate the constitution of bone.

Formation and self-organization kinetics of alpha-CD/PEO-based pseudo-polyrotaxanes in water. A specific behavior at 30 degrees C.

alpha-Cyclodextrins (alpha-CDs) have the ability to form inclusion complexes with poly(ethylene oxide) (PEO) polymer chains. These pseudo-polyrotaxanes (PPRs) can be obtained by quenching an alpha-CD/PEO mixture in water from 70 degrees C down to a lower temperature (typically in the range from 5 to 30 degrees C) thanks to favorable interactions between alpha-CD cavities and PEO chains. Moreover, starting from a liquid alpha-CD/PEO mixture at a total mass fraction of 15% w/w at 70 degrees C, the formation of PPRs with time at a lower temperature induces a white physical gel with time, and phase separation is observed.

pH-Switchable supramolecular "sliding" gels based on polyrotaxanes of polyethyleneimine-block-poly(ethylene oxide)-block-polyethyleneimine block copolymer and : synthesis and swelling behaviour.

A new type of pH-switchable supramolecular sliding gel has been synthesized, based on polyrotaxanes of polyethyleneimine-block-poly(ethylene oxide)-block-polyethyleneimine block copolymer and α-cyclodextrin. The three dimensional supramolecular network was obtained by an inter-molecular crosslinking reaction between CDs belonging to two different polyrotaxanes via 1,1'-carbonyldiimidazole. Higher gel equilibrium swelling has been observed in acidic medium than in basic medium.

Synthesis and characterization of high molecular weight polyrotaxanes: towards the control over a wide range of threaded α-cyclodextrins.

This work focuses on the synthesis of polyrotaxanes with high molecular weight template poly(ethylene glycol) PEG (20 kg mol) having various and well-defined amounts of α-cyclodextrins (α-CD) per chain from 3 up to 125. is the complexation degree of the polyrotaxane defined to be the average number of cyclodextrin molecules per template chain. The usual route has been used for high values of , while sparsely complexed polyrotaxanes have been synthesized with an original one pot synthesis in water.

Numerical simulation of polymerization in interdigital multilamination micromixers.

Free radical polymerization in microfluidic devices modeled with the help of numerical simulations is discussed. The simulation method used allows the simultaneous solvation of partial differential equations resulting from the hydrodynamics, thermal and mass transfer (convection, diffusion and chemical reaction). Three microfluidic devices are modeled, two interdigital multilamination micromixers respectively with a large and short focusing section, and a simple T-junction followed by a microtube reactor together considered as a bilamination micromixer with a large focusing section.