Alginate is a naturally occurring anionic polymer typically obtained from brown seaweed,
and has been extensively investigated and used for many biomedical applications, due to its biocompatibility, low toxicity, relatively low cost, and mild gelation by addition of divalent
cations such as Ca2+ [4]. Alginate hydrogels can be prepared by various cross-linking
methods, and their structural similarity to extracellular matrices of living tissues allows wide
applications in wound healing, delivery of bioactive agents such as small chemical drugs
and proteins, and cell transplantation. Alginate wound dressings maintain a physiologically
moist microenvironment, minimize bacterial infection at the wound site, and facilitate
wound healing. Drug molecules, from small chemical drugs to macromolecular proteins, can
be released from alginate gels in a controlled manner, depending on the cross-linker types
and cross-linking methods. In addition, alginate gels can be orally administrated or injected
into the body in a minimally invasive manner, which allows extensive applications in the
pharmaceutical arena. Alginate gels are also promising for cell transplantation in tissue
engineering. Tissue engineering aims to provide man-made tissue and organ replacements to
patients who suffer the loss or failure of an organ or tissue [5]. In this approach, hydrogels
are used to deliver cells to the desired site, provide a space for new tissue formation, and
control the structure and function of the engineered tissue [6]. In this review, general
properties of alginate and its current and potential applications in biomedical science and
engineering will be discussed.