Preparation And Application Of Paper-based Microfluidic Analytical Devices Based On Double-sided Adhesive

Paper-based microfluidic devices(μPADs)are microfluidic chips based on paper.Compared with chips based on silicon wafers,glass and ceramics,they have the advantages of low cost,no flow driver,easy processing and high biocompatibility,and are widely used in food safety,disease diagnosis and environmental protection.Currently,the main methods for preparing μPADs include laser lithography,flexographic printing,inkjet printing,etching and molten wax printing.However,these methods have limitations such as expensive equipment,tedious operation,need for chemical reagents to treat the filter paper,need for customised metal plate masks,and poor compatibility with hydrophobic materials.In this paper,a simple,low-costμPADs preparation method based on double-sided adhesive is developed,it’s performance is characterised,and a series of chemical analysis-related application experiments are carried out in combination with colourimetric,distance and counting detection,as follows.(1)A new method of preparing μPADs based on double-sided adhesive is proposed.The chip is prepared in two main steps: first,the hydrophobic material is made by dissolving the double-sided adhesive in toluene solution,and the hydrophobic material is deposited on the filter paper by embossing,spraying and drawing processes respectively;then,the filter paper with hydrophobic patterns is dried to produce the paper-based chip.Further,the optimal preparation conditions for the sequence of toluene spraying,the number of times the hydrophobic material is sprayed and drawn,the type of double-sided adhesive,the drying temperature and other parameters,as well as the optimal addition volume of the sample introduction zone and detection zones,were investigated.Compared to conventional methods of preparation,although the method is difficult to realize batch preparation,the preparation is simple,rapid and cost effective,single chip costs only 0.16 RMB and reparation time is only 10 min.(2)The comprehensive performance of μPADs based on double-sided adhesive was investigated.The performance of the μPADs based on double-sided adhesive was investigated in terms of various performance parameters such as contact angle,resolution and accuracy of the hydrophobic channels,and chemical compatibility of the hydrophobic materials.Compared with the most widely used method,wax printing,which is less compatible with organic solvents and surfactants,and whose resolution and accuracy are easily affected by the heating temperature,the chips prepared by this method have good hydrophobic performance,high resolution and accuracy,and show good chemical compatibility.(3)Three experimental studies were carried out for applications in the field of chemical analysis.The μPADs based on double-sided adhesive were applied to the colorimetric detection of kojic acid,the distance detection of bovine serum albumin(BSA),and the counting detection of the heavy metal ion nickel(II),respectively.The linear dynamic detection ranges were 0.05～4 mmol/L and 0.6～1.4g/L for kojic acid and BSA,respectively,and the semi-quantitative detection ranges were 0.5～8 mmol/L for nickel ions,with detection limits of 0.05 mmol/L,0.1 g/L and0.5 mmol/L,respectively,and demonstrated good selectivity or specificity,reproducibility,stability and recovery,indicating that the method has good results for the testing of real samples.Compared with traditional methods for the detection of these substances,although this method has a high detection limit,it simplifies the analysis steps,has good detection performance and avoids the use of expensive analytical instruments.In the future,it can be combined with the use of nanoparticles to achieve broad applications.