Publications & Research

This study presents a novel optoporation technique using a titanium-coated TiO2 microstructure (TMS) device activated by an infrared diode laser for highly efficient intracellular delivery. The TMS device, fabricated with 120 nm titanium coating on a titanium dioxide (TiO2) microstructure containing micro-needles (height $\sim2~\mu m$ and width $\sim4.5~\mu m)$, demonstrates enhanced biocompatibility and thermal conductivity compared to the conventional TiO2 microstructure (MS). Exposure to the TMS device with an IR diode laser (980 nm) generates heat, forming photothermal bubbles that disrupt the cell membrane and create transient pores for biomolecular delivery. Unlike traditional optoporation methods, which rely on large, vibration-sensitive lasers, the IR diode laser-assisted TMS device-based optoporation technique offers a compact, cost-effective, and portable alternative.

Microfluidic devices offer more accurate fluid flow control and lower reagent use for uniform nanoparticle synthesis than batch synthesis. Here, we propose a microfluidic device that synthesizes uniform iron oxide nanoparticles (IONPs) for highly efficient intracellular delivery. The 3D-printed device was fabricated, comprising two inlets in the T-shaped channel with an inner diameter of 2 mm, followed by a helical mixing channel with a single outlet. The unique geometries of this device enable accuracy and precision by allowing shortened reaction time and control fluid mixing, resulting in the production of homogenous NPs. By utilizing this device and using the co-precipitation method at room temperature, IONPs with an average cluster size of 90 nm were synthesized. The photothermal property of IONPs was explored through light-matter interaction using a nanosecond (ns) pulse laser at 1064 nm and a fluence of 35 mJ $cm^{-2}$, which helps to create transient cell membrane pores and deliver small to large biomolecules into cells by a simple diffusion process.

In this pioneering study, an infrared light-activated highly efficient and uniform, small to large biomolecular delivery into various cell types is developed using a flower-shaped microstructure device (FMD). Featuring a unique structural design, this FMD consists of 8 $\mu m$ in length, with edges of $\approx3$ and 20 $\mu m$ gaps between FMD microstructure. When subjected to IR laser exposure at 1050 nm, the FMD triggers the generation of photothermal cavitation bubbles, exerting jet fluid flow on the cell's plasma membrane surface, and facilitating biomolecule delivery into cells. The platform achieves efficient intracellular delivery spanning various biomolecules - from low-molecular-weight propidium iodide dye to higher molecular weight siRNA, plasmid, and enzymes - across human cervical (SiHa), mouse fibroblast (L929), and neural crest-derived (N2a) cancer cells, ensuring consistently high efficiency without compromising cell viability.

The recent advancements of single-cell analysis have significantly enhanced the ability to understand cellular physiology when compared to bulk cellular analysis. Here a massively parallel single-cell patterning and very large biomolecular delivery is reported. A micro-pillar polydimethyl siloxane stamp is used to pattern single-cells to small clusters of cells. For intracellular delivery of biomolecules into the patterned cells, a titanium micro-dish device is aligned on top of the cells and exposed by infrared light pulses. The platform successfully delivers small to very large biomolecules such as PI dyes (668 Da), dextran 3000 Da, siRNA (20-24 bp), and large size enzymes (464 KDa) in SiHa, L929 and MG63 cells. The platform is compact, robust, easy for printing, and potentially applicable for single-cell analysis.

Evaluation of glucose in cancerous tumours acts as a hall mark for cancer progression and thus serves as a major interest in these days. Here, we have developed a biocompatible, surface enhanced Raman spectroscopy-based glucose Nano Particle Sensor (SERS-gNPS) to measure glucose dynamically in 3D Co-cultured Colon Cancer Tumour Spheroids (3D-CCTS).

Anisotropic gold nanomaterials have always fascinated the scientific community; however, controlling their synthesis to achieve desired properties and monodispersity is challenging in a conventional batch reactor. Here, we report the synthesis of highly monodispersed dumbbell-shaped gold nanorods (Ds-Au NRs) in a droplet microfluidic device. The device comprises a tapered T-junction for reagent droplet production, a winding structure to promote nucleation, and lengthy parallel microchannels to support the slow growth required for dumbbell shape morphology. Compared to batch counterparts, reaction time was reduced to one-fifth and revealed higher monodispersity. The cytotoxicity analysis showed that microfluidic synthesised Ds-Au NRs are non-toxic and have great potential for usage in biomedical applications.

This work presents the use of microfluidic device-fabricated **spiky nano-burflower shape gold nanomaterials (nb-AuNPs)** to facilitate large biomolecule delivery into cells using **infrared light pulses**. Photothermal nanoparticle-sensitized intracellular delivery is a prominent non-viral technique. Branched nanostructures like nanostars exhibit unique properties like enhanced **localized surface plasmon resonance (LSPR)** in the near-infrared region. Adapting microfluidic technologies for branched nanostructure synthesis offers an alternative to conventional batch synthesis, providing uniform and high-quality particles.