Application Of Inkjet Printing Technology In Multidetection Immunoassay And 3D Printed Tissues/Organs

Inkjet printing is a digital and non-contact patterning technology, which has several advantages including easy-to-use simplified design and fabrication process, and low costs. Based on the application of immunochromatographic test strips in fluorescence detection, the multi-detection paper-based microfluidic devices were constructed by using the Inkjet printing technology. These devices can achieve the simultaneously detection of multiple biomarkers with the advantages including low costs, minimal required sample volume, wide detection range and low limit of detection. 3D biomimetic tissues/organs were constructed by Inkjet printing with biocompatibility and low cytotoxicity. The constructing approach allows us to vividly mimic the structure and function of tissues as well as design a variety of biological scaffolds according to research needs.Firstly, for the application in immunoassay, cardiac troponin I is a major serum biomarker and has been widely used in diagnosis of myocardial infraction with high sensitivity and specificity. As a preferred diagnosis method, point-of-care testing(POCT) can accurately reflect the timely myocardial damage through monitoring serum biomarkers. It is well-known that the immunochromatographic test strips can track the target analytes by using gold colloidal or fluorescent materials as markers. However, the test strips fabricated through traditional methods are disadvantageous in terms of sensitivity and can only detect one analyte at once. Therefore, it is highly desired a new technology to improve the performance of the test strips.Secondly, for the application in 3D biomimetic tissues, transdermal drug delivery is a topical dosage method through skin penetration. At the late stage research of transdermal drug delivery, researchers often use animals or living tissues as the in vivo models, which offers the long and large investments as well as ethical issues. 3D printed tissues/organs by Inkjet printing hold great potential for reducing the usage of animal model, saving costs for biomimetic researches, and thus providing experimental basis for further clinical research.This thesis mainly includes the following contents:(1) The immunochromatographic test strips based on immunochromatography were constructed for detection of cardiac biomarkers(cardiac troponin I). The optimal detection range is from 0.5 to 100 ng/m L. Paper-based microfluidic devices constructed by Inkjet printing could reduce the limit of detection to 0.01 ng/mL. Multi-channel microfluidic devices could also be constructed for simultaneous detection of multiple antibodies.(2) A 3D skin-like model was constructed by 3D inkjet printing collagen and fibroblasts in layerby-layer fashion. This 3D model has advantages of easy shaping, high stability and vividly mimicking the micro-environment. Using this 3D printing approach, 3 to 7-layer models were obtained by increasing cell layers. The thickness of each layer was estimated to be ca. 100 μm by confocal microscopy.(3) The 3D printed skin model was used for screening the penetration of nanoparticles. It provide foundamental data for future transdermal nanomedicine delivery researches. Polystyrene microspheres with same sizes but different surface charges were chosen as model nanoparticles. Amino-modified polystyrene microspheres with positive charge had the best permeability, suggesting the permeability of nanoparticles is related to their surface charges.