Advancements in nanotechnology have ushered in nanosponges, biodegradable polyester structures with nanometersized cavities, designed for targeted drug delivery. Initially developed for topical applications, these nanosponges have evolved to be administered orally and intravenously. They exhibit a porous structure for controlled drug release, addressing issues like toxicity and poor bioavailability. Capable of carrying both hydrophilic and lipophilic drugs, nanosponges serve as versatile carriers for substances like enzymes, proteins, vaccines, and antibodies. Their characteristics include size and polarity control, crystalline forms, non-toxicity, stability in various conditions, suspension and regeneration capabilities, and a 3D structure for targeted capture and release. The composition involves a polymer, a cross-linking agent, and specific drug criteria. Advantages encompass targeted delivery, flavor masking, reduced side effects, water solubility, adjustable particle size, and easy commercial production. Disadvantages include limited encapsulation for larger molecules. The mechanism involves an open structure allowing prolonged release. Various types based on cyclodextrin offer unique properties. Factors affecting nanosponges include polymer nature, drug characteristics, complexation temperature, and degree of substitution. Preparation methods include solvent, ultrasound-assisted, melt, bubble electrospinning, and emulsion solvent diffusion methods. Comprehensive characterization includes drug entrapment efficiency, saturation state interaction, in vitro release studies, porosity measurement, and spectroscopic techniques. Applications span solubility enhancement, sustained delivery, oral and topical systems, protein delivery, protection from degradation, pollutant removal from water, cancer treatment, antiviral applications, enzyme immobilization, and modulation of drug release.