3D Printing: The Second Dawn of Lab-On-Valve Fluidic Platforms for Automatic (Bio)Chemical Assays

In
this work, inexpensive manufacturing of unibody transparent
mesofluidic platforms for pressure-driven Lab-On-a-Valve (LOV) methodologies
is accomplished via rapid one-step 3D prototyping from digital models
by user-friendly freeware. Multichannel architecture having 800–1800
μm cross-sectional features with unconventional 3D conduit structures
and integrating optical and electrochemical detection facilities is
for the first time reported. User-defined flow-programming capitalizing
upon software control for automatic liquid handling is synergistically
combined with additive manufacturing based on stereolithographic 3D
printing so as to launch the so-called fourth generation of microflow
analysis (3D-μFIA). Using an affordable consumer-grade 3D printer
dedicated LOV platforms are 3D printed at will and prints are characterized
in terms of solvent compatibility, optical and mechanical properties,
and sorption of inorganic and organic species to prospect potentialities
for the unfettered choice of chemistries. The unique versatility of
the 3D-printed LOV device that is attached to a multiposition rotary
valve as a central design unit is demonstrated by (i) online handling
of biological materials followed by on-chip photometric detection,
(ii) flow-through bioaccessibility tests in exposome studies of contaminated
soils with miniaturized voltammetric detection, (iii) online phospholipid
removal by TiO2-incorporated microextraction approaches
using on-chip disposable sorbents, and (iv) automatic dynamic permeation
tests mimicking transdermal measurements in Franz-cell configurations.
A multipurpose LOV fluidic platform can be fabricated for less than
11 Euros.