The flexibility and hydrophilicity of nanogels suggest their potential for the creation of nanocarriers with good colloidal stability and stimulative ability. In the present study, biocompatible AGP and AGPA nanogels with triple-stimulative properties (thermosensitivity, pH sensitivity, and redox sensitivity) were prepared by incorporating poly(N-isopropylacrylamide) (PNIPAM) or poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-AA)) into alginate (AG) emulsion nanodrops, followed by fixation with a disulfide-containing molecule (cystamine dihydrochloride (Cys)). Compared to AG/PNIPAM(AGP) nanogels, AG/P(NIPAM-AA) (AGPA) nanogels exhibited more sensitive volumetric expansion by switching the temperature from 40 to 25 °C under physiological medium. This expansion occurs because P(NIPAM-AA) with -COOH groups can be fixed inside the nanogels via chemical bonding with Cys, whereas PNIPAM was encapsulated in the nanogels through simple physical interactions with the AG matrix. AGPA nanogels carrying an anticancer drug tend to easily enter cells upon heating, thereby exerting toxicity through a cold shock and reverse thermally induced release of an anticancer drug. Upon internalization inside cells, the nanogels use the reducible and acidic intracellular environments to effectively release the drug to the nucleus to impart anticancer activity. These results demonstrate that multifunctional nanogels may be used as a general platform for therapeutic delivery.

The original article to which this Erratum refers was published in J. Polym. Sci. Part A: Polym. Chem. (2004) 42(20) 5045–5053No abstract.

Although the special architecture of two-dimensional (2D) nanomaterials endows them with unique properties, their poor colloidal stability remains a main bottleneck to fully exploit their applications in the biomedical field. Herein, this study aims to develop a simple and effective approach to in situ incorporate 2D graphene oxide (GO) nanoplatelets into a thermosensitive matrix to acquire hybrid nanogels with good stability and photothermal effect. In order to improve its stability, GO firstly underwent silanization to its surface with double bonds, followed by intercalation with N-isopropylacrylamide (NIPAM) in the presence of a disulfide-containing crosslinker via an emulsion method. Radical polymerization was then initiated to accelerate direct GO exfoliation in PNIPAM nanogels by forming covalent bonds between them. The well-dispersed GO nanopletlets in the nanogels not only displayed an enhanced photothermal effect, but also improved the encapsulation efficiency of an anticancer drug. The hybrid nanogels accelerate drug release under conditions mimicking the acidic/reducible solid tumor and intracellular microenvironments, most importantly, it can be further enhanced via remote photothermal treatment. The multifunctional nanogels potentiate their synergistic anticancer bioactivity as an ideal nanoplatform for cancer treatment.

New multiblock copolymers derived from poly(Llactic acid) (PLLA) and poly(-caprolactone) (PCL) were prepared with the coupling reaction between PLLA and PCL oligomers with ONCO terminals. Fourier transform infrared (FTIR), 13 C NMR, and differential scanning calorimetry (DSC) were used to characterize the copolymers and the results showed that PLLA and PCL were coupled by the reaction between ONCO groups at the end of the PCL and OOH (or OCOOH) groups at the end of the PLLA. DSC data indicated that the different compositions of PLLA and PCL had an influence on the thermal and crystallization properties including the glass-transition temperature (T g ), melting temperature (T M ), crystallizing temperature (T c ), melting enthalpy (⌬H m ), crystallizing enthalpy (⌬H c ), and crystallinity. Gel permeation chromatography (GPC) was employed to study the effect of the composition of PLLA and PCL and reaction time on the molecular weight and the molecular weight distribution of the copolymers. The weight-average molecular weight of PLLA-PCL multiblock copolymers was up to 180,000 at a composition of 60% PLLA and 40% PCL, whereas that of the homopolymer of PLLA was only 14,000. A polarized optical microscope was used to observe the crystalline morphology of copolymers; the results showed that all polymers exhibited a spherulitic morphology. Keywords: poly(lactic acid); poly(-caprolactone); block copolymers; melt polycondensation; copolymerization; synthesis Muhuo Yu is a Professor and head of Department of Materials, College of Material Science and Engineering, Donghua University, Shanghai, China. He holds a B.S. from Zhejiang University, an M.S. from East China Normal University, and a Ph.D. from Donghua University. In 1985 he joined Donghua University as polymer chemist. His recent research interests are in development of a new process to synthesize low-cost lactic-acid based polymer and its use as general polymer materials; development of low-cost nanomaterials and hyperbranched polymer and its application in polymer process and polymer surface modifications; and development of in situ polymerization process to produce long fiber reinforced thermoplastic composites and nanoparticle/polymer composites.

To develop multifunctional anticancer nanomedicines, photothermal nanogels with multistimulative properties are fabricated by hybridizing graphene oxide (GO) with poly(N-isopropylacrylamide, PNIPAM) matrix. This technique allows for easy monomer-intercalation between GO sheets, followed by in situ polymerization to promote GO exfoliation as nanoplatelets inside emulsified PNIPAM nanodrops, followed by fixation using a disulfide-containing cross-linker. The resulting nanogels own significantly improved colloidal stability and biocompatibility as compared to native GO. They can effectively encapsulate an anticancer drug and accelerate its release under conditions mimicking acidic/reducible solid tumor and intracellular microenvironments. Drug delivery can be further enhanced via remote photothermal treatment. The local photothermal effect and drug release smartness make the nanogels as an ideal nanoplatform for synergistic anticancer therapy upon their arrival at tumor tissue or inside cancer cells.