The blood–brain barrier (BBB) is a barrier that separates the blood from the brain tissue and possesses unique characteristics that make the delivery of drugs to the brain a great challenge. To achieve this purpose, it is necessary to design strategies to allow BBB passage, in order to reach the brain and target the desired anatomic region. The use of nanomedicine has great potential to overcome this problem, since one can modify nanoparticles with strategic molecules that can interact with the BBB and induce uptake through the brain endothelial cells and consequently reach the brain tissue. This review addresses the potential of nanomedicines to treat neurological diseases by using nanoparticles specially developed to cross the BBB.

The use of marine-origin polysaccharides has increased in recent research because they are abundant, cheap, biocompatible, and biodegradable. These features motivate their application in nanotechnology as drug delivery systems; in tissue engineering, cancer therapy, or wound dressing; in biosensors; and even water treatment. Given the physicochemical and bioactive properties of fucoidan and chitosan, a wide range of nanostructures has been developed with these polysaccharides per se and in combination. This review provides an outline of these marine polysaccharides, including their sources, chemical structure, biological properties, and nanomedicine applications; their combination as nanoparticles with descriptions of the most commonly used production methods; and their physicochemical and biological properties applied to the design of nanoparticles to deliver several classes of compounds. A final section gives a brief overview of some biomedical applications of fucoidan and chitosan for tissue engineering and wound healing.

This chapter aims to provide an overview of the advances and achievements in brain drug delivery systems, providing a wide coverage of strategies and possible applications in the field of nanomedicine. It focuses on the efficient design of noninvasive nanocarrier systems that can facilitate drug delivery to specific regions of the brain and the factors that influence their transport through the bloodstream to the therapeutic target place. Several nanosystems have been exploited in order to accomplish the desired brain drug delivery, namely liposomes, lipid nanoparticles (NPs), polymeric NPs, Cyclodextrins, dendrimers, silica NPs, magnetic NPs, gold NPs, quantum dots and carbon nanotube. The efficient delivery of many therapeutic and diagnostic compounds to specific areas of the brain has been constrained because the existence of a protective barrier that restricts drugs that can enter the brain upon systemic administration, the blood-brain barrier.