Fast three-dimensional micropatterning of PC12 cells in rapidly crosslinked hydrogel scaffolds using ultrasonic standing waves.

The ability to spatially organise the microenvironment of tissue scaffolds unlocks the potential of many scaffold-based tissue engineering applications. An example application is to aid the regeneration process of peripheral nerve injuries. Herein, we present a promising approach for three-dimensional (3D) micropatterning of nerve cells in tissue scaffolds for peripheral nerve repair.

Printing in situ tissue sealant with visible-light-crosslinked porous hydrogel.

To reflect the rapidly growing interest in producing tissue sealants using various chemical/physical processes, we report an approach using visible light to control the crosslinking of 3D printable hydrogels as in situ tissue sealant. Gelatin-hydroxyphenylpropionic acid conjugate (Gtn-HPA) is shown to crosslink effectively within 30 s under visible light in the presence of [RuII(bpy)] and sodium persulphate, which is sufficiently rapid for surgery use. Porous structure can be also introduced by including carboxylmethyl cellulose-tyramine (CMC-Tyr) as a precursor.

Rapid Enhancement of Cellular Spheroid Assembly by Acoustically Driven Microcentrifugation.

Intense acoustically driven microcentrifugation flows are employed to enhance the assembly of cellular spheroids in the microwell of a tissue culture well plate. This ability to interface microfluidics with commonly used tissue culture plasticware is a significant advantage as it can potentially be parallelized for high throughput operation and allows existing analytical equipment designed to fit current laboratory formats to be retained. The microcentrifugation flow, induced in the microwell coated with a low adhesive hydrogel, is shown to rapidly enhance the concentration of cells into tight aggregates within a minute-considerably faster than the conventional hanging drop and liquid overlay methods, which typically require days-while maintaining their viability.

In situ generation of tunable porosity gradients in hydrogel-based scaffolds for microfluidic cell culture.

Compared with preformed anisotropic matrices, an anisotropic matrix that allows users to alter its properties and structure in situ after synthesis offers the important advantage of being able to mimic dynamic in vivo microenvironments, such as in tissues undergoing morphogenesis or in wounds undergoing tissue repair. In this study, porous gradients are generated in situ in a hydrogel comprising enzymatically crosslinked gelatin hydroxyphenylpropionic acid (GTN-HPA) conjugate and carboxylmethyl cellulose tyramine (CMC-TYR) conjugate. The GTN-HPA component acts as the backbone of the hydrogel, while CMC-TYR acts as a biocompatible sacrificial polymer.

Effects of GDNF-loaded injectable gelatin-based hydrogels on endogenous neural progenitor cell migration.

Brain repair following disease and injury is very limited due to difficulties in recruiting and mobilizing stem cells towards the lesion. More importantly, there is a lack of structural and trophic support to maintain viability of the limited stem/progenitor cells present. This study investigates the effectiveness of an injectable gelatin-based hydrogel in attracting neural progenitor cells (NPCs) from the subventricular zone (SVZ) towards the implant.

Injectable 3D hydrogel scaffold with tailorable porosity post-implantation.

Since rates of tissue growth vary significantly between tissue types, and also between individuals due to differences in age, dietary intake, and lifestyle-related factors, engineering a scaffold system that is appropriate for personalized tissue engineering remains a significant challenge. In this study, a gelatin-hydroxyphenylpropionic acid/carboxylmethylcellulose-tyramine (Gtn-HPA/CMC-Tyr) porous hydrogel system that allows the pore structure of scaffolds to be altered in vivo after implantation is developed. Cross-linking of Gtn-HPA/CMC-Tyr hydrogels via horseradish peroxidase oxidative coupling is examined both in vitro and in vivo.

Tumor inside a pearl drop.

The confined internal space of a liquid marble, as well as its porous and non-adhesive shell, offers an attractive application possibility - accommodating living cells inside liquid marbles. Cancer cells in suspension may aggregate to form three dimensional structures, also known as cancer cell spheroids (CCS). In this study, CCS formation inside liquid marble is investigated.

Three-dimensional nanocharacterization of porous hydrogel with ion and electron beams.

Porous hydrogels provide an excellent environment for cell growth and tissue regeneration, with high permeability for oxygen, nutrients, and other water-soluble metabolites through their high water-content matrix. The ability to image three-dimensional (3D) cell growth is crucial for understanding and studying various cellular activities in 3D context, particularly for designing new tissue engineering scaffold, but it is still challenging to study cell-biomaterial interfaces with high resolution imaging. We demonstrate using focused ion beam (FIB) milling, electron imaging, and associated microanalysis techniques that novel 3D characterizations can be performed effectively on cells growing inside 3D hydrogel scaffold.

N,N'-Carbonyldiimidazole-mediated functionalization of superparamagnetic nanoparticles as vaccine carrier.

Particulates with specific sizes and characteristics can induce potent immune responses by promoting antigen uptake of appropriate immuno-stimulatory cell types. Magnetite (Fe(3)O(4)) nanoparticles have shown many potential bioapplications due to their biocompatibility and special characteristics. Here, superparamagnetic Fe(3)O(4) nanoparticles (SPIONs) with high magnetization value (70emug(-1)) were stabilized with trisodium citrate and successfully conjugated with a model antigen (ovalbumin, OVA) via N,N'-carbonyldiimidazole (CDI) mediated reaction, to achieve a maximum conjugation capacity at approximately 13 microgmicrom(-2).