Cell wall The primary cell wall of land plants is composed of the polysaccharides cellulose, hemicelluloses and pectin. Often, other polymers such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae possess cell walls made of glycoproteins and polysaccharides such as carrageenan and agar that are absent from land plants. In bacteria, the cell wall is composed of peptidoglycan. The cell walls of archaea have various compositions, and may be formed of glycoprotein S-layers, pseudopeptidoglycan, or polysaccharides. Fungi possess cell walls made of the N-acetylglucosamine polymer chitin. Unusually, diatoms have a cell wall composed of biogenic
Polymer-drug conjugates tested in drug conjugates. Due to successful clinical proof-of-concept, second-generation conjugates are now being developed. Experimental chemotherapy and novel polymer-based combinations are currently under investigation. Instead of passive targeting developed so far, new approaches will provide receptor-mediated delivery. This will enable selective delivery of anticancer conjugates. A natural polymer dextrin and pendant chain polyacetals, have shown ability of pH-dependent degradation after incorporation into cell compartments. Also diethylstilboestrol (DES) conjugates can undergo pH-dependent degradation. Polymer-Directed Enzyme Prodrug Therapy (PDEPT) is an example of two-step anticancer treatment. Polymer-drug conjugates Polymer-drug conjugates are nano-medicine products under development for cancer diagnosis and treatment. There