New technique for needle-less implantation of eukaryotic cells.
OBJECTIVE
On review of the use of stem cells in the literature, promissory outcomes for functional organ recovery in many subspecialties in medicine underscore its therapeutic potential. The application of stem cells through the use of a needle can result in additional scar formation, which is undesired for delicate organs. The present work describes the use of a needle-less stem cell injector with the Immediate Drop on Demand Technology (I-DOT) for cell injection in vitro.


METHODS
Mesenchymal stromal cells from human bone marrow were labeled with ethynyl-deoxyuridine (EdU) for 2 days and then were re-suspended. With the use of I-DOT, the cells were applied to type 1 collagen matrices or pig bladder tissue specimens with or without mucosa at different levels of energy. The collagen matrices were analyzed after 4 h and 5 days; bladder tissue specimens were analyzed 4 h after cell implantation. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT) assay was performed immediately after cell application to the collagen matrices. Histological analysis with the use of frozen sections and immunofluorescence was used to localize EdU-labeled cells.


RESULTS
A considerable number of cells were detected by use of the MTT assay for collagen matrices. In the collagen matrix, the mean measured depth immediately after application ranged between 210 μm and 489 μm, 220 μm and 270 μm for entire bladder specimens, and 230 μm and 370 μm for bladder without mucosa. Cells survived for up to 5 days in the collagen matrix in both bladder specimens.


CONCLUSIONS
Cells can survive during I-DOT application, which suggests that the I-DOT device may be a potentially suitable technology for needle-less cell application onto tissues.
Urology Department, Karl-Eberhard University of Tübingen, Germany. Electronic address: luisepm64@gmail.com.
Luis Fernando
LF
Arenas da Silva
Fraunhofer Institute for Manufacturing Engineering and Automation IPA, Stuttgart, Germany.
Lena
L
Schober
Radboud University Medical Center, Nijmegen, The Netherlands.
Marije
M
Sloff
Fraunhofer Institute for Manufacturing Engineering and Automation IPA, Stuttgart, Germany.
Andrea
A
Traube
Urology Department, Karl-Eberhard University of Tübingen, Germany.
Melanie L
ML
Hart
Radboud University Medical Center, Nijmegen, The Netherlands.
Wout F J
WF
Feitz
Urology Department, Karl-Eberhard University of Tübingen, Germany.
Arnulf
A
Stenzl
D000818:Animals; D003094:Collagen / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism; D004867:Equipment Design; D006801:Humans; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation / Q000295:instrumentation* / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D009339:Needles; D013552:Swine; D001743:Urinary Bladder / Q000637:transplantation
D024042:Collagen Type I; D003094:Collagen
cell injection; cell therapy; collagen matrix; ethynyldeoxiuridine; needle-less; stem cells