A potential nanograde antibiotic with hyperbranched architecture was synthesized from melt esterification of poly(ethylene glycol) or PEG and Citric acid or CA with 1:1 mol composition. PEG of different molecular weights, c.a. 4000, 6000 and 20,000 were used during the polyesterification. The polyester molecules of nanometric size were highly water soluble and showed a melting point between 55 and 60 °C. The branching status was established from spectroscopy, flow behaviour (viscosity) and rheological evidences. The extent of branching and flowability, both were reduced as the molecular weight of PEG was increased. During in-vitro pathological study, all the grades showed reasonably strong antibacterial affect (both with gram positive and negative bacteria), high selectivity, biocompatibility and controlled generation of reactive oxygen species or ROS, however, the grade with maximum level of branching and functional chain ends displayed highest therapeutic efficiency, may that be considered further as a potential agent for next level investigation. © 2019 Elsevier B.V.