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miRNAs are small non-coding RNA molecules which serve as promising biomarkers due to their important roles in the development and progression of various cancer types. The detection of miRNAs is of vital importance to the early-stage diagnostics and prognostics of multiple diseases. However, traditional detection strategies have faced some challenges owing to the intrinsic characteristics of miRNAs including small size, short sequence length, low concentration level and high sequence homology in complex real samples. To overcome these challenges, we proposed a MXene-enhanced plasmonic biosensor for real-time and label-free detection of miRNA. By utilizing MXene nanomaterial which possesses unique characteristics including large surface area and strong carrier confinement abilities, we tuned the absorption of our plasmonic sensing substrate to reach a “zero-reflection” state and induced an extremely sharp phase change at the resonance angle. Combined with the sensing mechanism based on phase-induced lateral displacement measurement, this MXene-enhanced plasmonic biosensor can achieve a much superior sensing performance compared to traditional SPR devices. Based on this biosensing scheme, the ultrasensitive detection of target miRNA with a detection limit down to 10 fM has been successfully demonstrated. More importantly, single-base mismatched miRNA can be easily distinguished from the target miRNA according to the sensing signal. Furthermore, our plasmonic biosensor is capable of detecting miRNA in complex media such as 100 % human serum samples without compromising the detection sensitivity. This MXene-enhanced plasmonic sensing scheme has the ability of detecting miRNAs with extremely low concentration levels in complex surrounding media without the need of introducing extra labels or amplification tags, which holds great potential in various biological applications and clinical diagnostics.

• High-molecular-weight star polymer exhibited enhanced transfection efficiency. • Performance of star polymer was superior to the linear polymer. • Star polymer transfected better in cancer cells than fibroblast-like cells. Gene therapy shows much promise in treating many inheritable and acquired diseases, but challenges remain in the design of gene vectors with low cytotoxicity and high transfection efficiency. Elucidating the structure-function relationship of non-viral polymer-based gene carriers is crucial for improving the design and performance of safe and effective gene therapy approaches. The cationic poly(2-aminoethyl methacrylate) (PAEM) containing primary amino side groups is an attractive carrier for gene delivery. This study focuses on four PAEM-based polycations with well-defined molecular weight and chain architecture. The polymers include three cyclodextrin (CD)-cored star-shaped PAEM polycations (s-PAEM), synthesized by atom transfer radical polymerization (ATRP), and a linear PAEM polycation (l-PAEM), synthesized via activators regenerated by electron transfer (ARGET) ATRP. All four polycations could condense plasmid DNA (pDNA) into spherical polyplexes with small sizes (<200 nm). The polyplexes showed excellent stability during storage and were able to resist electrostatic destabilization. The cytotoxicity of these polycations was depended on dose and target cell type and was influenced by molecular weight and chain architecture, yet the polyplexes showed little cytotoxicity regardless of the type of polymer used. The transfection efficiency of PAEM polycations was highly dependent upon molecular weight, molecular architecture (star versus linear) and target cell type. In most cases, polyplexes formed by high-molecular-weight s-PAEM performed the best. Moreover, at a specific N/P ratio, the transfection efficiency mediated by s-PAEM was higher in MCF-7 breast cancer cells than in COS-7 fibroblast-like cells, but such cell-type dependence was not obvious for l-PAEM. These findings indicate that the star-shaped PAEM polycations could be promising gene carriers for gene therapy applications. [ABSTRACT FROM AUTHOR]

Polymer–protein core–corona particles can be used as multifunctional platforms in biological and medical applications. In this research, we prepared poly(2-hydroxyethyl methacrylate)–bovine serum albumin (PHEMA–BSA) core–corona particles by the “grafting from” method. In order to prepare the particles, activators generated by electron transfer for atom transfer radical polymerizations (AGET ATRP) of HEMA initiated by a BSA macroinitiator were performed. The polymerizations were conducted in the presence of ppm amounts of transition metal catalyst and ascorbic acid. Transmission electron microscopy, atomic force microscopy, dynamic light scattering and ξ-potential measurements were used to characterize the core–corona particles. The average size and ξ-potentials of the particles are strongly dependent on the amounts of BSA used in AGET ATRP. The secondary structure and bioactivity of the protein molecules in the coronae of the particles were studied. In vitro cytotoxicity assays and cell uptake assays indicate that the biohybrid particles are nontoxic and can be internalized into the cells. The polymer–protein core–corona particles will find applications in drug delivery and biomedical imaging. [ABSTRACT FROM AUTHOR]

ABSTRACT The purpose of this study was to develop a poly(γ-glutamic acid) (γ-PGA)-based hydrogel loaded with superoxide dismutase (SOD) to accelerate wound healing. First, γ-PGA was modified with taurine (γ-PGAS), and then the SOD-loaded γ-PGAS/γ-PGA hydrogel (SOD-PGAS/PGA-H) was prepared by cross-linking of ethylene glycol diglycidyl ether. The swelling behavior and water vapor transmission rate revealed that PGAS/PGA-H could create a moist environment for wound surface. In vitro kinetics of SOD release showed that SOD released from PGAS/PGA-H maintained high activity and SOD-PGAS/PGA-H effectively scavenged the superoxide anion. The results of our fibroblast proliferation experiments showed that PGAS/PGA-H had good cytocompatibility. The effects of SOD-PGAS/PGA-H on wound healing were examined in a Type I diabetic rat model with full-thickness wounds. Twenty-one days after grafted to wounds, SOD-PGAS/PGA-H exhibited a higher rate of wound healing than control group and showed increased collagen deposition and epithelialization. SOD-PGAS/PGA-H seems to promote better wound healing and thus might be a promising candidate for wound healing management. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42033. [ABSTRACT FROM AUTHOR]

DNA vaccine is a third generation vaccine type based on concepts and techniques of molecular biology. It can closely mimic live infections and induce both antibody and cell mediated immune responses and thus has much potential for treating chronic viral infection and cancer. How do we transport the DNA vaccine to the right target cells in lymphoid tissues and organs? How do we achieve high and robust gene transfection efficiency while simultaneously inducing DC maturation and antigen presentation? These questions pose significant challenges and addressing them may require serious efforts in developing better biomaterials as carriers. This review is dedicated to the discussion of polymers as nanoscale carriers for the DNA vaccine. We summarize recent advances in polymer science and engineering to overcome multilevel hurdles for DNA vaccine delivery and conclude with thoughts on challenges and opportunities that may shape the future of polymers in DNA vaccination.