Polymer-based nanocarriers are created from natural or synthetic polymers that are modified to form submicroscopic particles. The polymer matrix can be customized to provide specific properties, such as surface chemistry and flexibility. This allows the particles to be designed and used in different fields. They are promising nanomaterials that are used as therapeutic and diagnostic agents, and they have potential biomedical and environmental applications. These nanocarriers are polymers that can be engineered with other types of nanomaterials with different sizes, shapes, and compositions. They can deliver drugs or their cargo to a specific site with precisely controlled release. They have many advantages compared to traditional drug delivery carriers, including improved biocompatibility, reduced toxicity, and increased efficacy. In biomedical applications, polymer nanocarriers have been used as drug delivery carriers, cancer therapy, and gene therapy. In environmental applications, polymer nanocarriers are able to remove heavy metals and other contaminants from air and water bodies. In this review, a summary of recent fabrication, design, synthesis, characterisation, and various applications in the biomedical and environmental fields has been provided. The review also highlights the current challenges and prospects of evolving polymer nanocarriers.
