Institute of Chemical Technology

Reactive oxygen species play an integral role in physiological signaling but contribute to pathology when dysregulated. Elevated ROS levels in diseased tissues such as tumors, inflamed sites, and ischemic regions present unique biochemical triggers for targeted drug delivery. Furthermore, strategies utilizing exogenously generated ROS (e.g., via photodynamic action) provide an alternative route for spatiotemporal control. This review summarizes recent advances in ROS-responsive systems, beginning with the chemistry of ROS-cleavable linkers and the design of nanocarrier platforms capable of spatiotemporally controlled release. The integration of these carriers with theranostic functions is highlighted as a strategy to enhance selectivity and reduce systemic toxicity. Applications across oncology, inflammatory disorders, ischemia-reperfusion injury, and regenerative medicine illustrate the breadth of therapeutic potential. Key design considerations including sensitivity thresholds, payload compatibility, and surface functionalization are discussed alongside translational challenges such as stability, reproducibility, and scalability. Emerging opportunities, notably patient-specific redox profiling and biosensor-guided adaptive delivery are identified as promising routes to clinical translation. By bridging redox biology with materials science and nanomedicine, ROS-triggered drug delivery platforms demonstrate the capacity to exploit endogenous oxidative cues for improved therapeutic precision and safety, positioning them as a transformative approach in the development of next-generation controlled release systems.

Plastic waste, particularly low-density polyethylene (LDPE), poses severe environmental challenges due to its low bio-degradability and limited recycling potential. In this study, a solvent-assisted catalytic steam reforming approach is investigated, in which LDPE is finely dispersed in ethylene glycol (EG) to enable homogeneous feed delivery for hydrogen production. Steam reforming experiments were conducted over 20 wt% Ni-Co/Al2O3-ZrO2 catalyst synthesized via sol-gel and wet impregnation methods. The bimetallic catalyst exhibited high surface area (136 m2 g- 1), strong metal-support interaction (SMI), and improved thermal stability confirmed through characterization techniques including XRD, BET, FESEM, FTIR, and TGA-DSC analyses. Systematic optimization of operating parameters such as metal loading, steam-to-carbon ratio (S/C), gas hourly space velocity (GHSV), and temperature revealed optimal conditions at S/C = 9, GHSV = 810 h- 1, and 500°C. Under these conditions, it achieved 95% feed conversion, 92.72% hydrogen yield, and 97.6% selectivity. The synergistic interaction between Ni and Co enhanced reforming kinetics and suppressed coke formation, enabling stable operation. Compared to previous reports on ethylene glycol or PET reforming, the current work improved hydrogen yield by 5-10%, validating its potential for direct plastic-to-hydrogen conversion. Overall, the results demonstrate the potential of solvent-assisted reforming as a controlled platform for hydrogen generation from waste polymer-derived carbon.