Selenium has several unique biological effects in many aspects, making use of bioactive components and inorganic selenium to prepare antitumor organic selenium compounds will have a great significant impact on cancer therapy and patient wellbeing. It was well-known that Se—Se bond is very reactive and sensitive to the dual redox environment, therefore, we can take advantage of such feature to prepare diselenide-containing polymers which can be applied in the area of drug controlled release. In this paper, we prepared amphiphilic diselenide copolymers with diselenide-containing diols (HO-SeSe-OH), isophorone diisocyanate (IPDI), and water soluble low-molecular chitosan (LW-CS). The synthetic copolymers were characterized by means of gel permeation chromatography (GPC), ¹H NMR and FTIR spectroscopy. The molecular weight of CS-PUSeSe-CS copolymer was 4.42×10⁴ g/mol which calculated according to the integral ratio of the peaks at δ 4.00 and 4.42 which related to CH₂O groups of chitosan and NHCOOCH₂ groups of IPDI, respectively. The size distribution of aggregates measured by dynamic light scattering (DLS) measurements, which gave a result of about 130 nm in average diameter. The critical aggregate concentration (CAC) of aggregates was measured by the fluorescent probe method and the result was 0.01 mg/mL. The dual redox responsive of aggregates was studied both in VC and H₂O₂ solution, the results showed that amphiphilic diselenide copolymer would cause Se—Se chain scission in no matter weak oxidative or reductive ambient environment. Although negative charged drug-rhodamine B (RB) could not release out from aggregates due to electrostatic attraction. However, positive charged drug-doxorubicin hydrochloride (Doxo) can easily release from aggregates in reductive VC solution by analyzing UV-spectra at the wavelength of 500 nm, indicating aggregates assembled from diselenide-containing copolymers may act as powerful and efficient bionano reactors and realize controllable drug delivery by breaking Se—Se bonds.

Key words: diselenide, amphiphilic copolymer, dual redox, Doxo, drug release