Table 2.

Preparation method of paper-based microfluidic chips.

Methods	Advantages	Disadvantages
Photolithography	The earliest method for making paper chips, precise channel structure [20]	The process is complicated The resulting paper chips are not suitable for bending [8]
Plasma treatment technology	More suitable for mass production and have low cost [21]	Depends on templates, reducing flexibility [22]
Wax printing	Simple processing, environmentally friendly materials [23,24]	Rely on wax spray printers, heating-induced horizontal diffusion reduces structure accuracy [25]
Inkjet method	Simple processing can be drawn with ink pen, no heating diffusion, more precise structure [26,27]	Hydrophobic inks can be toxic, ink pens are inaccurate for hand drawing, still rely on inkjet printers [28]
Screen printing	Ideal for mass production, simple process, and low cost [29,30]	Rely on templates, greatly reducing flexibility during research [31]
Laser processing technology	Very precise structures can be prepared [32]	Rely on expensive laser equipment and difficult to popularize [33]
3D origami method	3D structure has more functions, direct registration of each layer [34,35]	Means of fixing are required between layers, only single material can be used [36]
3D lamination method	3D structure has more functions, can use a variety of materials [37]	Fixed means are required between layers, registration methods are required [38]
Other 3D methods	Highly innovative and has huge development potential [39]	Special uses, difficult to promote [40]