Droplet-based lab-on-chip platform integrated with laser ablated graphene heaters to synthesize gold nanoparticles for electrochemical sensing and fuel cell applications

Abstract

Controlled, stable and uniform temperature environment with quick response are crucial needs for many lab-on-chip (LOC) applications requiring thermal management. Laser Induced Graphene (LIG) heater is one such mechanism capable of maintaining a wide range of steady state temperature. LIG heaters are thin, flexible, and inexpensive and can be fabricated easily in different geometric configurations. In this perspective, herein, the electro-thermal performance of the LIG heater has been examined for different laser power values and scanning speeds. The experimented laser ablated patterns exhibited varying electrical conductivity corresponding to different combinations of power and speed of the laser. The conductivity of the pattern can be tailored by tuning the parameters which exhibit, a wide range of temperatures making them suitable for diverse lab-on-chip applications. A maximum temperature of 589 °C was observed for a combination of 15% laser power and 5.5% scanning speed. A LOC platform was realized by integrating the developed LIG heaters with a droplet-based microfluidic device. The performance of this LOC platform was analyzed for effective use of LIG heaters to synthesize Gold nanoparticles (GNP). Finally, the functionality of the synthesized GNPs was validated by utilizing them as catalyst in enzymatic glucose biofuel cell and in electrochemical applications.

A lab-on-chip platform for simultaneous culture and electrochemical detection of bacteria

“…Laser induced graphene film was utilized as a heating source. The selection of power and speed, structural morphology and electrical and thermal characterization were described in detail in our previous work ( Srikanth et al., 2021 ). In brief, a polyimide sheet of 250 μm thickness was adhered to a glass substrate and a CO 2 laser of 10.6 μm wavelength was lased over the polyimide sheet to obtain laser induced graphene ( Kothuru et al., 2020 ).…”

Microfluidic preparation of optical sensors for biomedical applications

“…Reproduced under terms of the CC-BY license. 69 Copyright 2021, The Authors, published by Springer Nature. (E) Diagram and image of a 3D printed microfluidic device for metal NPs synthesis.…”

“…68 Considering the requirements for a controllable, uniform, and stable temperature environment, Srikanth et al designed a laserinduced-graphene heater and integrated it with droplet microfluidics to synthesize AuNPs with good electrochemical properties (Figure 5D). 69 It is worth mentioning that new technologies, such as 3D printing have been applied to the construction of microfluidic chips that meet the reaction conditions for metal NPs synthesis. For example, Bressan et al applied a fused deposition modeling (FDM)-based 3D-printed microfluidic device to the synthesis of AuNPs and AgNPs.…”

“…designed a laser‐induced‐graphene heater and integrated it with droplet microfluidics to synthesize AuNPs with good electrochemical properties (Figure 5D). 69 …”

Synthesis and characterization of linear/nonlinear optical properties of graphene oxide and reduced graphene oxide-based zinc oxide nanocomposite

“…Graphene has offered a unique two-dimensional (2D) sp 2 -hybridized structure and great properties such as high mechanical flexibility, superior electrical and thermal conductivities, large specific surface area, and high chemical stability 5 – 11 . Because of these characteristics, graphene has various applications including in supercapacitors 12 , 13 , photovoltaics 14 – 16 , fuel cells 17 – 19 , sensors 20 , 21 and nanofluids 22 , 23 . Moreover, 2D crystal structure of Graphene can make it more popular in order to load diverse materials or form various composites that enhance the beneficial features of both graphene and the added components 24 .…”