PAPER BASED MICROFLUIDIC ANALYTICAL DEVICE WITH PREFABRICATED CUSTOMIZED TEST ZONE

摘要

The present invention relates to a novel design and preparation of the paper based microfluidic device with prefabricated customized test for convenient preparation of the test zone for spotting different reagents with accuracy. The negative photolithographic method was used to prepare the device with certain modifications to generate a partial photoresist layer on the rear of the device to block the leakage of sample as per the co-pending patent application 1126/KOL/2014. Also the external application of the test zone on the hydrophobic photoresist treated paper prevents sample leakage at the test zone site. The partial layer of photoresist on the device limits sample volume to 7±0.2 µl as compared to devices without the partial photoresist layer which requires a larger sample volume of 10±0.1 µl. The design prototype for the device with customized test zone exploits the slight protrusions on the UV exposed photoresist treated paper to bridge the externally applied test zone to the sample and absorbent zones. Comparisons of flow rates of the devices fabricated were done. The laminated device with inbuilt test zone has a greater flow rate of 3.3±1.2 mm/min compared to 1.8±0.9 mm/min of laminated device with external test zone. The efficacy of the prepared device was studied with colorimetric assays for the non-specific detection of protein by tetrabromophenol blue, acid/base with phenolphthalein indicator and specific detection of proteins using the HRP-DAB (Horseradish peroxidase -3,3-Diaminobenzidine tetra hydrochloride) chemistry. The prepared device has the potential for leak proof detection of analyte, requires low sample volume, involves reduced cost of production (Rs 1.6 or $ 0.03, excluding reagent cost) and enables the integration of customized test zones.