Nano-liter perfusion microfluidic device made entirely by two-photon polymerization for dynamic cell culture with easy cell recovery

Abstract

Polydimethylsiloxane (PDMS) has been the material of choice for microfluidic applications in cell biology for many years, with recent advances encompassing nano-scaffolds and surface modifications to enhance cell-surface interactions at nano-scale. However, PDMS has not previously been amenable to applications which require complex geometries in three dimensions for cell culture device fabrication in the absence of additional components. Further, PDMS microfluidic devices have limited capacity for cell retrieval following culture without severely compromising cell health. This study presents a designed and entirely 3D-printed microfluidic chip (8.8 mm × 8.2 mm × 3.6 mm) using two-photon polymerization (2PP). The ‘nest’ chip is composed of ten channels that deliver sub-microliter volume flowrates (to ~ 600 nL/min per channel) to 10 individual retrievable cell sample ‘cradles’ that interlock with the nest to create the microfluidic device. Computational fluid dynamics modelling predicted medium flow in the device, which was accurately validated by real-time microbead tracking. Functional capability of the device was assessed, and demonstrated the capability to deliver culture medium, dyes, and biological molecules to support cell growth, staining and cell phenotype changes, respectively. Therefore, 2PP 3D-printing provides the precision needed for nanoliter fluidic devices constructed from multiple interlocking parts for cell culture application.

Direct laser writing-enabled 3D printing strategies for microfluidic applications

“…9c). 227 This latter work is notable not only because-unlike the majority of works in the literature based Fig. 9 Fully DLW-printed microfluidic systems.…”

“…9c ). 227 This latter work is notable not only because—unlike the majority of works in the literature based on the use of commercial DLW printers from Nanoscribe GmbH—the authors used a NanoOne DLW printer from the company, UpNano GmbH, but also because the researchers leveraged a recent innovation for increasing the efficiency of DLW printing processes: “Dynamic Optical Tuning (DOT)”. 227,228 …”

“…With the recent emergence of commercial DLW printers equipped with such capabilities from companies such as Nanoscribe and UpNano, this scenario could soon come to fruition. Yet, to the authors' knowledge, only the aforementioned work by McLennan et al has demonstrated the use of such DOT approaches for microfluidic applications; 227 however, this lack of such reports is most likely a consequence of how recently such printers became available commercially ( i.e. , within the past few years) and—due to their somewhat prohibitive costs ( e.g.…”

Two-photon polymerization with a 780 nm monolithic diode laser

“…7 Due to this high process resolution and freedom of shape, 2PP has become increasingly attractive in various research fields such as micro-optics, 8,9 tissue engineering, 10,11 biomedical applications, 12,13 and micro-fluidics. 14,15 However, a major drawback of 2PP is the very high cost of the required systems, 16 which slows down the further widespread use of 2PP as a manufacturing tool in research and industry. One main contributor to this high cost is the required ultra-short pulsed laser source.…”

Microfluidic Gradient Culture Arrays for Cell Pro-oxidation Analysis Using Bipolar Electrochemiluminescence

“…A microfluidic chip is a kind of small integrated experimental platform that has attracted a lot of attention in recent years. It is popular in the field of small-scale analysis, especially in the detection of biological samples and the cultivation of bionic cell models. − Microfluidic devices made of materials such as glass or polydimethylsiloxane (PDMS) not only have excellent optical properties and biocompatibility but also can be easily modified on the surface, which makes it relatively feasible for bioanalysis on them. − Using the mixing and diffusion of solutes, gradients can be easily formed on a microfluidic device, which could provide excellent solutions for the rapid generation and testing of batch samples with different conditions. − The microfluidic gradients and culture array can save unnecessary labor, time, and sample costs, while continuous injection can achieve information with greater fidelity. So microfluidic gradient arrays are widely used for drug screening and conditions determination. − At present, there are two kinds of important detection methods for microfluidic chips.…”