Stereolithographic Rapid Prototyping of Clear, Foldable, Non-Refractive Intraocular Lens Designs: A Proof-of-Concept Study.

Purpose: A cataract is a cloudy area in the crystalline lens. Cataracts are the leading cause of blindness and the second cause of severe vision impairment worldwide. During cataract surgery, the clouded lens is extracted and replaced with an artificial intraocular lens, which restores the optical power.

Synthesis and Formulation of Four-Arm PolyDMAEA-siRNA Polyplex for Transient Downregulation of Collagen Type III Gene Expression in TGF-β1 Stimulated Tenocyte Culture.

The natural healing process for tendon repair is associated with high upregulation of collagen type III, leading to scar tissue and tendon adhesions with functionally deficient tendons. Gene delivery systems are widely reported as potential nanotherapeutics to treat diseases, providing a promising approach to modulate collagen type III synthesis. This work investigates a proof-of-concept four-arm cationic polymer-siRNA polyplex to mediate a transient downregulation of collagen type III expression in a tendon cell culture system.

Induction of Tendon-Specific Markers in Adipose-Derived Stem Cells in Serum-Free Culture Conditions.

Herein, we describe the tenogenic effect of bone morphogenetic protein-12 and transforming growth factor-β1 in cultured adipose-derived stem cells (ADSCs) in serum-free conditions. This culture system provides an insight into serum-free culture conditions in stem cell differentiation protocols. A positive response of the ADSCs to the tenogenic induction was observed.

Biocompatible Three-Dimensional Printed Thermoplastic Scaffold for Osteoblast Differentiation of Equine Induced Pluripotent Stem Cells.

Horses, like humans, can experience bone fractures and due to their large size and the need to bear weight on all limbs during the recovery period, they can be difficult to treat. Surgical techniques to improve fracture repair are improving, but to date, regenerative medicine technologies to aid fracture healing are not commonly applied in horses. We have previously demonstrated that equine induced pluripotent stem cells (iPSCs) can be differentiated into bone forming osteoblasts in 2D culture.

Synthesis and Fabrication of Surface-Active Microparticles Using a Membrane Emulsion Technique and Conjugation of Model Protein via Strain-Promoted Azide-Alkyne Click Chemistry in Physiological Conditions.

The rapid surface immobilization of protein on monodispersed polyester microcarriers is reported. A model protein, functionalized with a dibenzocyclooctyne core, immobilizes on the surface of azide-terminal polycaprolactone microcarriers within 10 min compared to 12 h for other conjugation techniques, and it is conducted in physiological conditions and in the absence of coupling reagents.

A Clinical, Biological, and Biomaterials Perspective into Tendon Injuries and Regeneration.

Tendon injury is common and debilitating, and it is associated with long-term pain and ineffective healing. It is estimated to afflict 25% of the adult population and is often a career-ending disease in athletes and racehorses. Tendon injury is associated with high morbidity, pain, and long-term suffering for the patient.

A thermoresponsive and magnetic colloid for 3D cell expansion and reconfiguration.

A dual thermoresponsive and magnetic colloidal gel matrix is described for enhanced stem-cell culture. The combined properties of the material allow enzyme-free passaging and expansion of mesenchymal stem cells, as well as isolation of cells postculture by the simple process of lowering the temperature and applying an external magnetic field. The colloidal gel can be reconfigured with thermal and magnetic stimuli to allow patterning of cells in discrete zones and to control movement of cells within the porous matrix during culture.

Evaluation of a thermoresponsive polycaprolactone scaffold for in vitro three-dimensional stem cell differentiation.

Tissue engineering (TE) strategies aim at imitating the natural process of regeneration by using bioresorbable scaffolds that support cellular attachment, migration, proliferation, and differentiation. Based on the idea of combining a fully degradable polymer [poly(ɛ-caprolactone)] with a thermoresponsive polymer (polyethylene glycol methacrylate), a scaffold was developed, which liquefies below 20°C and solidifies at 37°C. In this study, this scaffold was evaluated for its ability to support C2C12 cells and human adipose-derived stem cells (ASCs) to generate an expandable three-dimensional (3D) construct for soft or bone TE.

Programmable polymer-DNA hydrogels with dual input and multiscale responses.

Combination switchable polymer-DNA hydrogels have been synthesized to respond to both a specific oligonucleotide recognition signal and a non-specific but biorelevant environmental trigger. The hydrogels exhibit rheological properties that can be modulated through interaction with complementary DNA strands and/or reduction. Furthermore, individual and combined oligonucleotide recognition and reduction responses allow control over pore sizes in the gel, enabling programmable release and transport of objects ranging from the nano- to micro-scale.

Gelatin embedding for the preparation of thermoreversible or delicate scaffolds for histological analysis.

Thermoreversible hydrogels for tissue engineering (TE) purposes have gained increased attention in recent years as they can be combined with cells and drugs and directly injected into the body. Following the fate of transplanted cells in situ is essential in characterizing their distribution and survival, as well as the expression of specific markers or cell-matrix interactions. Existing histological embedding methods, such as paraffin wax embedding, can mechanically damage some biomaterials during processing.

Thermoresponsive hyperbranched copolymer with multi acrylate functionality for in situ cross-linkable hyaluronic acid composite semi-IPN hydrogel.

Thermoresponsive polymers have been widely used for in situ formed hydrogels in drug delivery and tissue engineering as they are easy to handle and their shape can easily conform to tissue defects. However, non-covalent bonding and mechanical weakness of these hydrogels limit their applications. In this study, a physically and chemically in situ cross-linkable hydrogel system was developed from a novel thermoresponsive hyperbranched PEG based copolymer with multi acrylate functionality, which was synthesized via an 'one pot and one step' in situ deactivation enhanced atom transfer radical co-polymerization of poly(ethylene glycol) diacrylate (PEGDA, M(n) = 258 g mol(-1)), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA, M(n )= 475 g mol(-1)) and (2-methoxyethoxy) ethyl methacrylate (MEO(2)MA).

"One-step" preparation of thiol-ene clickable PEG-based thermoresponsive hyperbranched copolymer for in situ crosslinking hybrid hydrogel.

A well-defined poly(ethylene glycol) based hyperbranched thermoresponsive copolymer with high content of acrylate vinyl groups was synthesized via a "one-pot and one-step" deactivation enhanced atom transfer radical polymerization approach, which provided an injectable and in situ crosslinkable system via Michael-type thiol-ene reaction with a thiol-modified hyaluronan biopolymer. The hyperbranched structure, molecular weight, and percentage of vinyl content of the copolymer were characterized by gel permeation chromatography and (1)H NMR. The lower critical solution temperature of this copolymer is close to body temperature, which can result in a rapid thermal gelation at 37 °C.

The reverse of polymer degradation: in situ crosslinked gel formation through disulfide cleavage.

In contrast to the usual inclusion of disulfide bonds within a polymer structure to facilitate bio-degradation, we have designed a self-curing "one pot" hyperbranched polymer capable of forming crosslinked gels under reducing conditions abundant in tumoural tissue.

Modular construction of multifunctional bioresponsive cell-targeted nanoparticles for gene delivery.

Multifunctional and modular block copolymers prepared from biocompatible monomers and linked by a bioreducible disulfide linkage have been prepared using a combination of ring-opening and atom-transfer radical polymerizations (ATRP). The presence of terminal functionality via ATRP allowed cell-targeting folic acid groups to be attached in a controllable manner, while the block copolymer architecture enabled well-defined nanoparticles to be prepared by a water-oil-water double emulsion procedure to encapsulate DNA with high efficiency. Gene delivery assays in a Calu-3 cell line indicated specific folate-receptor-mediated uptake of the nanoparticles, and triggered release of the DNA payload via cleavage of the disulfide link resulted in enhanced transgene expression compared to nonbioreducible analogues.

Facile synthesis of responsive nanoparticles with reversible, tunable and rapid thermal transitions from biocompatible constituents.

Responsive polymeric nanoparticles composed of hybrid block co-polymers were prepared from biocompatible components that displayed rapid, tunable and multiply reversible transitions in response to change of temperature.

Ion-sensitive "isothermal" responsive polymers prepared in water.

Ion-sensitive responsive polymers are prepared under fully aqueous conditions using controlled radical polymerization. Variations in comonomer content and sequence lead to temperature and salt-dependent solution behavior, with cloud-points ranging by +/-40 degrees C following addition of Hofmeister series salts. A "hybrid" block copolymer, composed of a statistical sequence of monomers tipped with a hydrophilic block, formed stable micelle-like assemblies that exhibited burst release of an encapsulated model drug in response to addition of a kosmotrope, Na2SO4, at room temperature.