A single molecular probe for multi-analyte (Cr³âº, Al³âº and Fe³âº) detection in aqueous medium and its biological application.

An ESIPT based fluorescent sensor 1 was developed, which could selectively detect and differentiate trivalent metal ions Cr(3+), Al(3+) and Fe(3+) in aqueous medium. The cell imaging experiments confirmed that 1 can be used for monitoring intracellular Cr(3+) and Al(3+) levels in living cells.

Stacked stem cell sheets enhance cell-matrix interactions.

Cell sheet engineering has enabled the production of confluent cell sheets stacked together for use as a cardiac patch to increase cell survival rate and engraftment after transplantation, thereby providing a promising strategy for high density stem cell delivery for cardiac repair. One key challenge in using cell sheet technology is the difficulty of cell sheet handling due to its weak mechanical properties. A single-layer cell sheet is generally very fragile and tends to break or clump during harvest. Effective transfer and stacking methods are needed to move cell sheet technology into widespread clinical applications. In this study, we developed a simple and effective micropipette based method to aid cell sheet transfer and stacking. The cell viability after transfer was tested and multi-layer stem cell sheets were fabricated using the developed method. Furthermore, we examined the interactions between stacked stem cell sheets and fibrin matrix. Our results have shown that the preserved ECM associated with the detached cell sheet greatly facilitates its adherence to fibrin matrix and enhances the cell sheet-matrix interactions. Accelerated fibrin degradation caused by attached cell sheets was also observed.

Responsive systems for cell sheet detachment.

Cell sheet engineering has been progressing rapidly during the past few years and has emerged as a novel approach for cell based therapy. Cell sheet harvest technology enables fabrication of viable, transplantable cell sheets for various tissue engineering applications. Currently, the majority of cell sheet studies use thermo-responsive systems for cell sheet detachment. However, other responsive systems began showing their potentials for cell sheet harvest. This review provides an overview of current techniques in creating cell sheets using different types of responsive systems including thermo-responsive, electro-responsive, photo-responsive, pH-responsive and magnetic systems. Their mechanism, approach, as well as applications for cell detachment have been introduced. Further development of these responsive systems will allow efficient cell sheet harvesting and patterning of cells to reconstruct complex tissue for broad clinical applications.

Rapid cell sheet detachment using spin-coated pNIPAAm films retained on surfaces by an aminopropyltriethoxysilane network.

The ability to harvest cell sheets grown on thermoresponsive polymers, such as poly(N-isopropylacrylamide) (pNIPAAm), has been widely studied for use in tissue engineering applications. pNIPAAm is of special interest because of the phase change that it undergoes in a physiologically relevant temperature range. Two primary approaches have been adopted to graft pNIPAAm chains covalently onto tissue culture polystyrene dishes: electron beam irradiation and plasma polymerization. These approaches often involve non-easily accessible (e.g. e-beam) facilities and complicated procedures that have hindered most tissue culture laboratories in adopting this technology for their specific applications. In this study, we developed a simple and cost-effective approach to create thermoresponsive surfaces using commercially available pNIPAAm. Using a simple spin-coating technique, thermoresponsive thin films were deposited on glass slides or silicon wafers using pNIPAAm blended with a small amount of 3-aminopropyltriethoxysilane (APTES), which enhances the retention of pNIPAAm on the surface. We found that the thermoresponsive films created using our method support cell attachment and proliferation without additional adhesive proteins as well as cell sheet detachment within minutes.