# Polymers and Polymer Nanocomposites for Cancer Therapy +
## 3 Biopolymers and Biopolymer Nanocomposites
Ketoprofen-loaded CS was made by modifying cytoprotective nonionic block copolymer poloxamer 188 (a non-ionic linear copolymer composed of two hydrophilic side chains and a hydrophobic center core) and also varying the time and amplitude of ultrasonication [50]. Nanoparticles were also prepared by ionic gelation between CS and tripolphosphate. Following their study, the researchers considered that one may anticipate their contribution to the advancement of a gene and drug delivery system [51]. Micro/nanoparticles of CS-grafted PEG methacrylate (PEGMA) (CS-g-PEGMA) with a size ranging from 200 to 900 nm were prepared through double-crosslinking (ionic and covalent) applied in a reverse emulsion technique. The carrier obtained showed nontoxicity and hemocompatibility, and it is considered to be a potential delivery agent for the controlled release of bevacizumab, an ophthalmic drug. The other benefits of this carrier are a lower administered dose, prolonged release, the effectiveness of local delivery, and targeted administration through local injection next to the retina [52]. The roles and mechanisms of _Cyclocarya paliurus_ polysaccharide (CPP) have been investigated. The results of the study suggested that CPP may enhance thyroid cancer cell apoptosis by suppressing the activation of p-Akt, Akt, and Bcl-2 and activating Bax, which provides for the novel use of CPP as a thyroid cancer treatment [53]. CUR is the principal curcuminoid of turmeric, a member of the ginger family, which is often used as a drug against cancer tumors. Its application as a viable drug is impeded by its low solubility. For efficient delivery at the cancer tumor site, amphiphilic block copolymers made of poly (alkyl-2-oxazoline) (PAOx) were synthesized. The CUR-loaded PAOx nanoparticles, sized around 100 nm, exhibited excellent stability and enhancement of the aqueous solubility of CUR. In vitro release studies demonstrated their potential chemical relevance as a promising nanocarier able to circumvent the limitations of CUR [54]. Thiolated starch-coated nano-iron oxide particles (nFe\({}_{3}\)O\({}_{4}\)) containing CUR was developed to investigate cytotoxicity in lymphocytes and cancer cell lines. Nanoparticles with a 5% polymer coating showed a drug encapsulation efficiency up to 78%, while the loading efficiency was greater than 80%. A cytotoxicity assay revealed excellent compatibility of the system with lymphocyte cells, while it still had a considerable amount of cytotoxicity in cancer cell lines [55]. A bioconjugated alginate (AA)-CUR, was synthesized and used to prepare stable calcium crosslinked spherical micelles serving as a carrier for CUR. The bioconjugate, at a concentration of 0.7 mg/mL, decreased the viability of cancer cells by about 80%. The cellular uptake of AA-CUR was detected within one hour after treatment. The AA-CUR micelles can serve as an effective and safe delivery vehicle for CUR [56]. To evaluate metoxy-PEG-b-poly (\(\delta\)-valerolactone) (mPEG-b-PVL) as a carrier, CUR was loaded in the copolymer using thin film hydration. The encapsulation efficiency and yield CUR released from the nanoparticles continued for one month. The nanoparticles obtained (130 nm in size) could obviously increase CUR solubility in water and improve its pharmacokinetic properties. The results of the research confirmed the potential of the mPEG-b-PVL copolymer as a carrier for CUR [57]. Functional multilayer polymeric micelles were obtained through the self-assembly of a poly(ethylene oxide)-b-poly (n-butyl acrylate)-b-poly (acrylic acid) (PEO-b-PnBA-b-PAA) triblock terpolymer and exploited like a template for nAg being bound by a PAA block. CUR was loaded in the hydrophobic PnBA micellar cores. The effect of a combination of two anticancer agents released from the micelles on the vitality of acute myeloid leukemia (HL-60), its multidrug-resistant subline HL60/DOX, and human urinary bladder carcinoma (Ej) cells was assessed. The in vitro experiments revealed efficacy with regard to the cytotoxic activity of nAg and CUR nanoparticles [58].