Anjali Singh supervised by Dr. Anshu Sarje received her Master of Science  in  Electronics and Communication Engineering (ECE). Here’s a summary of her research work on Development of a Cost-Effective Flexible Microheater for Lab-On-A-Chip applications and Material characteristics of popular soft materials for application in Microfluidic/Biomedical devices: Review:

This thesis explores the dual objectives of reviewing material characteristics of soft polymers for microfluidic and Lab-on-a-Chip (LOC) devices and developing a cost-effective, flexible microheater for LOC applications. Soft materials such as polydimethylsiloxane (PDMS), hydrogels, thermoplastic elastomers, and conducting polymers are analyzed for their mechanical, thermal, chemical, optical, and biocompatibility properties. These polymers play a crucial role in LOC systems due to their ability to provide flexibility, durability, and compatibility with biological samples. The review delves into their fabrication techniques, solubility in common solvents, adhesion, and surface modification methods, highlighting their relevance for applications such as diagnostics, cell culture, and chemical assays. Experimental studies further assess their optical properties and cytotoxicity, offering a comprehensive understanding of their potential for use in biomedical and chemical systems. By comparing the advantages and limitations of these materials, this work aids in optimizing material selection for enhanced performance and sustainability in LOC applications. The developed flexible microheater utilizes nichrome wire embedded in a PDMS substrate, chosen for its affordability and durability. The microheater operates within a temperature range of 40°C to 150°C, with precise control achieved through a pulse-width modulation (PWM)-based circuit and feedback from a 100k $\Omega$ NTC thermistor. This setup provides closed-loop temperature regulation, ensuring stability and adaptability for diverse applications. The microheater’s efficacy is demonstrated in two significant applications: glucose detection and the synthesis of silver nanoparticles (AgNPs). In the glucose detection application, the microheater integrated into a microwell device reliably facilitates Benedict’s test, confirming its potential for point-of-care diagnostics. The microheater is also employed in the synthesis of AgNPs using green chemistry principles, utilizing ascorbic acid as a reducing agent and sodium citrate as a stabilizer. This process yields spherical nanoparticles with UV-Vis absorption peaks characteristic of AgNPs (between 405 nm and 411 nm). Both applications underline the microheater’s capacity to deliver consistent performance while maintaining low fabrication costs. Experimental results validate the heater’s capability to reach steady-state temperatures quickly and efficiently. The integration of the PWM based control system ensures rapid response times and enhanced accuracy, addressing challenges in conventional heating systems. Furthermore, the cost of the microheater device is kept below INR 1000, making it an accessible solution for resource-constrained settings. This study offers a substantial contribution to the field of LOC systems by combining an in-depth review of soft materials with the practical development of a cost-efficient and flexible microheater. The findings pave the way for further advancements in affordable and accessible technologies for biomedical, chemical, and diagnostic applications.

March 2025