Non-cytotoxicity or good biocompatibility is an essential requisite for the thermo-sensitive polymeric materials used in the biomedical fields. In this study, a new poly(Nacetyl-L-glutamic acid-co-lysine ester) (PGAL) with excellent thermo-sensitivity and biocompatibility is synthesized from natural lysine and glutamic acid. The chemical structures of the monomers and polymers are determined by 1 H NMR, FTIR spectrum, and GPC. PGAL shows a reversible lower critical solution temperature (LCST) of 17.3-31.7°C, and the thermo-sensitivity is affected by its molecular weight, structure, and concentration. The viability of HeLa cells in 0.01-10 μg/mL PGAL solution is found to be in a range of 98-110 % after 24, 48, and 72 h of incubation. To sum up, this new thermo-sensitive PGAL has excellent biocompatibility that makes it a promising material in the biomedical fields.

A new thermosensitive poly( N -propionyl-aspartic acid/ethylene glycol) (PPAE) with no cytotoxicity and an upper critical solution temperature (UCST) is synthesized by polycondensation of L -aspartic acid and ethylene glycol. The chemical structures of the monomer and polymer are confi rmed by FTIR and 1 H NMR spectroscopy, and by elemental analysis measurements. Turbidimetric measurements indicate that PPAE shows a reversible UCST phase transition at 1.5-37.6 °C in pure water or an alcohol/water mixture. The UCST can be facilely tuned via changing the content of alcohol in water or the normal saline. Moreover, the survival rate of HeLa cells to PPAE is close to 100% within 48 h, demonstrating no cytotoxicity. Such aspartic acid-based polymers with tunable thermosensitivity could be useful in the biomedical fi eld.

The non‐toxicity or good biocompatibility is an inevitable requirement for thermosensitive polymers because of their extensive biomedical applications. In this investigation, a facile and instructional guidance is developed for the molecular design of the thermosensitive polymeric material. A family of thermosensitive poly(lysine ester‐diacetoxy tartaric acid)s (PLEDT) with good biocompatibility is then designed and successfully prepared on the basis of natural lysine and tartaric acid. The structure of the monomers and polymers is systematically confirmed by Fourier transfrom IR (FTIR) spectroscopy, 1H NMR, elemental analysis, and gel‐permeation chromatography (GPC) measurements. The temperature‐dependent characteristics from UV data reveals that PLEDT shows a reversible lower critical solution temperature (LCST) of about 7–35 °C depending on the molecular weight, concentration, and the salt. Additionally, the high viability of HeLa cells by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay demonstrates no detectable cytotoxicity of PLEDT at all test concentrations up to 100 μg mL−1. In conclusion, the novel thermosensitive PLEDT with good biocompatibility can be a promising material in the biomedical field.

The continuous use of nonsteroidal anti-inflammatory drugs such as ibuprofen frequently leads to some serious side-effects including stomach ulcers and bleeding. In this paper, two kinds of new biocompatible polyesters (PIGB, PIGH) and polyesteramide (PIGA) comprising biodegradable components (L-glutamic acid, 1,4-butanediol, and 1,6-hexanediol and 6-amino hexanol) and ibuprofen as pendant group have been prepared by the melting polycondensation. The chemical structures of the monomer and polymers are characterized by FTIR, 1 H NMR spectrum, GPC, and contact angle measurements. The drug loading of ibuprofen reaches very high level (35-37%) for PIGB, PIGH, and PIGA carriers. The free ibuprofen molecules are released in vitro from polymer carriers in a controlled manner without a burst release, different from the release pattern observed in the other drugencapsulated systems. It is also found that the different hydrophilicity among PIGB, PIGH, and PIGA plays a key role in the timecontrolled release of ibuprofen. In addition, the viability of HeLa cells after 48 h of incubation reaches more than 100%, indicating no cytotoxicity for PIGB, PIGH, and PIGA carriers.