Applications of marine-derived chitosan and alginates in biomedicine / 生物医学工程学杂志

Marine-derived biopolymers are excellent raw materials for biomedical products due to their abundant resources, good biocompatibility, low cost and other unique functions. Marine-derived biomaterials become a major branch of biomedical industry and possess promising development prospects since the industry is in line with the trend of "green industry and low-carbon economy". Chitosan and alginates are the most commonly commercialized marine-derived biomaterials and have exhibited great potential in biomedical applications such as wound dressing, dental materials, antibacterial treatment, drug delivery and tissue engineering. This review focuses on the properties and applications of chitosan and alginates in biomedicine.

Environmental stimuli-sensitive biodegradable drug delivery systems / 生物医学工程学杂志

Environmental stimuli-sensitive biodegradable drug delivery systems are drawing more and more attentions because of their advantages such as smart properties, high efficiency and easy-to-handle properties. On the basis of a large quantity of references on this topic, a review has been made on the developments of the thermosensitive and pH-sensitive intelligent polymeric systems for drug delivery.

Study on thermo-sensitive intelligent targeting type drug carriers (II) microcapsules with grafted thermo-sensitive gates / 生物医学工程学杂志

Environmental stimuli-responsive microcapsules are getting more and more interests because of their potential applications in site-specific and time- and rate-programmed controlled-release. In this study, thermo-responsive microcapsules with linear grafted poly(N-isopropylacrylamide) (PNIPAM) gates on the inner pore surface were prepared, and the thermo-responsive controlled-release experiments were carried out. Interfacial polymerization was introduced to prepare polyamide porous microcapsules, and plasma-graft pore-filling polymerization was used to graft PNIPAM into the pore of the microcapsule membranes. The experimental results showed that PNIPAM-grafted microcapsules were featured with thermo-responsiveness due to the thermoresponsive swollen-shrunken property of PNIPAM chains grafted on the inner pore surface of the microcapsule membrane. At temperatures below the lower critical solution temperature (LCST), the linear grafted PNIPAM chains on the inner pore surface were in the swollen state, and the pores in the membrane were closed and the solute molecules were restrained to pass, as a result the release rate was low. In contrast, the grafted PNIPAM chains were in the shrunken state at temperatures above the LCST, and therefore the pores in the membrane were open, and a high release rate was the result.

Study on thermo-sensitive intelligent targeting type drug carriers (I) porous membranes with grafted thermo-sensitive gates / 生物医学工程学杂志

Thermo-responsive intelligent membranes with linear grafted poly(N-isopropylacrylamide) (PNIPAM) gates on the inner pore surface were prepared, and experiments were carried out on the thermo-responsive gating characteristics. Plasma-graft pore-filling polymerization was used to graft PNIPAM into the pore of the porous flat membranes. The experimental results showed that PNIPAM-grafted PVDF (PNIPAM-g-PVDF) membranes were featured with thermo-responsiveness due to the thermo-responsive swollen-shrunken property of PNIPAM chains grafted on the inner pore surface of the membrane. At temperatures below the lower critical solution temperature (LCST), the linear grafted PNIPAM chains on the inner pore surface were in the swollen state, and the pores in the membrane were closed; in contrast, the grafted PNIPAM chains were in the shrunken state at temperatures above the LCST, and therefore the pores in the membrane were open. The LCST of the thermo-sensitive gates could be adjusted by adding acrylamide (AAM) in the N-isopropylacrylamide (NIPAM) monomer solution, the LCST of the poly(NIPAM-co-AAM) gates increased simply with the increase of the AAM fraction.