The purpose of this study was to prepare low molecular weight alginic acid (LMWA) nanoparticles by cation-induced, controlled gelification of depolymerized alginic acid for effective drug delivery to drug resistant bacteria. The depolymerization reaction was performed using potassium persulfate oxidation at an optimized condition. The optimized conditions for depolymerization were anticipated to be $37^{circ}C$, pH 4, 2 days reaction time, and a 0.075 M concentration of potassium persulphate containing 0.001 M silver nitrate in the final reaction mixture. Gel permeation chromatography showed depolymerized alginic acid had an average molecular weight of $20.95{pm}0.49$ kDa. Depolymerized alginic acid was also characterized for its structural integrity by X-ray diffraction, nuclear magnetic resonance, and Fourier transform spectroscopy. Depolymerized alginic acid was used to prepare low molecular weight nanoparticles with a particle size of $54{pm}0.41$ nm, and a zetapotential of $-32.2{pm}3.91$ mV. The nanoparicles were then subjected to tetracycline loading. In vitro drug loading and drug release efficiencies after 100 h were determined to be $66.56{pm}1.88$ and $61.8{pm}0.141%$, respectively. Finally, the minimal inhibitory concentration and a putative mode of action for the tetracycline nanoparticles were determined using tetracycline resistant bacteria, Escherichia coli XL-1.