Fluorescent Glycopolymer Nanoparticles Based on Aggregation‐Induced Emission Dyes: Preparation and Bioimaging Applications

Aggregation‐induced emission (AIE) dye‐based fluorescent glycopolymers nanoparticles (FGNs) are synthesized with abundant carbohydrate groups on the surface for the first time. This is carried out firstly by free radical polymerization between AIE monomer (PhE) and a renewable biobased monomer itaconic anhydride (ITA), then by the ring‐opening reaction between ITA and glucosamine hydrochloride, to obtain glycopolymers with plenty of glycosyl groups on them. The resulted amphiphilic glycopolymer is prone to self‐assemble into nanoparticles with high water dispersibility due to the surplus carboxyl groups and glycosyl groups covered on the surface, which can also be further functionalized. The obtained nanoparticles demonstrate strong fluorescence emission, owning to the AIE dyes in the core of nanoparticles. Biocompatibility evaluation and cell uptake behavior of the nanoparticles are further investigated to explore their potential biomedical applications; the demonstrated excellent biocompatibility makes them promising for cell imaging.

     

Oxygen‐Mediated Reactions in Photopolymerizable Radical Thin Films: Application to Simultaneous Photocuring Under Air and Nanoparticle Formation

Titanium propoxide, titanium isopropoxide, and titanium (triethanolaminato) isopropoxide are proposed as high‐performance additives to overcome the oxygen inhibition effects in the free radical photopolymerization of a low‐viscosity monomer thin film, under air and upon a low‐intensity UV light activation. Indeed, when added to a Type I photoinitiator such as bis(2,4,6‐trimethylbenzoyl)‐phenylphosphine oxide (BAPO), noticeably higher conversions are achieved under air (48% vs. 30%). The in situ formation of Ti‐based nanoparticles is also observed. The photochemical properties of these types of Ti‐based compounds as well as their interaction with BAPO are investigated by steady‐state photolysis and electron spin resonance. Molecular orbital calculations give an interesting insight into the possible reactions. A chemical mechanism is also proposed.

     

Polydiacetylene Nanotubes in Heterogeneous Catalysis: Application to the Gold‐Mediated Oxidation of Silanes

A layer‐by‐layer approach is used to anchor small gold nanoparticles onto organic nanotubes resulting from the self‐assembly and polymerization of diacetylene‐containing nitrilotriacetic amphiphiles. The obtained nanotube–gold hybrid is used as a catalyst for the aerobic oxidation of various silanes. With minimal gold loading (0.05 mol%), all substrates are converted into the corresponding silanols with hydrogen gas as the only by‐product. The catalyst operates under mild conditions and can be easily recycled, losing neither activity nor selectivity.

     

Antibacterial‐nanocomposite bone filler based on silver nanoparticles and polysaccharides

Injectable bone fillers represent an attractive strategy for the treatment of bone defects. These injectable materials should be biocompatible, capable of supporting cell growth and possibly able to exert antibacterial effects. In this work, nanocomposite microbeads based on alginate, chitlac, hydroxyapatite and silver nanoparticles were prepared and characterized. The dried microbeads displayed a rapid swelling in contact with simulated body fluid and maintained their integrity for more than 30 days. The evaluation of silver leakage from the microbeads showed that the antibacterial metal is slowly released in saline solution, with less than 6% of silver released after 1 week. Antibacterial tests proved that the microbeads displayed bactericidal effects toward Staphylococcus aureus, Pseudomonas aeruginosa and Staphylococcus epidermidis, and were also able to damage pre‐formed bacterial biofilms. On the other hand, the microbeads did not exert any cytotoxic effect towards osteoblast‐like cells. After characterization of the microbeads bioactivity, a possible means to embed them in a fluid medium was explored in order to obtain an injectable paste. Upon suspension of the particles in alginate solution or alginate/hyaluronic acid mixtures, a homogenous and time‐stable paste was obtained. Mechanical tests enabled to quantify the extrusion forces from surgical syringes, pointing out the proper injectability of the material. This novel antibacterial bone filler appears as a promising material for the treatment of bone defects, in particular when possible infections could compromise the bone‐healing process. Copyright © 2016 John Wiley & Sons, Ltd.     

The scope and conventions of evidence‐based medicine need to be widened to deal with “too much medicine”

In order that evidence‐based medicine can prevent “too much medicine”, it has to provide evidence in support of “gold standard” findings for use as diagnostic criteria, on which the assessment of other diagnostic tests and the outcomes of randomized controlled trials depend. When the results of such gold standard tests are numerical, cut‐off points have to be positioned, also based on evidence, to identify those in whom offering a treatment can be justified. Such a diagnosis depends on eliminating conditions that mimic the one to be treated. The distributions of the candidate gold standard test results in those with and without the required outcome of treatment are then used with Bayes rule to create curves that show the probabilities of the outcome with and without treatment. It is these curves that are used to identify a cut‐off point for offering a treatment to a patient and also to inform the patient's decision to accept or reject the suggested treatment. This decision is arrived at by balancing the probabilities of beneficial outcomes against the probabilities of harmful outcomes and other costs. The approach is illustrated with data from a randomized controlled trial on treating diabetic albuminuria with an angiotensin receptor blocker to prevent the development of the surrogate end‐point of “biochemical nephropathy”. The same approach can be applied to nonsurrogate outcomes such as death, disability, quality of life, relief of symptoms, and their prevention. Those with treatment‐justifying diagnoses such as “diabetic albuminuria” usually form part of a broader group such as “type 2 diabetes mellitus”. Any of these can be made the subject of evidence‐based differential diagnostic strategies.     

Polymeric micro/nanoparticles: Particle design and potential vaccine delivery applications

Particle based adjuvant showed promising signs on delivering antigen to immune cells and acting as stimulators to elicit preventive or therapeutic response. Nevertheless, the wide size distribution of available polymeric particles has so far obscured the immunostimulative effects of particle adjuvant, and compromised the progress in pharmacological researches. To conquer this hurdle, our research group has carried out a series of researches regarding the particulate vaccine, by taking advantage of the successful fabrication of polymeric particles with uniform size. In this review, we highlight the insight and practical progress focused on the effects of physiochemical property (e.g. particle size, charge, hydrophobicity, surface chemical group, and particle shape) and antigen loading mode on the resultant biological/immunological outcome. The underlying mechanisms of how the particles-based vaccine functioned in the immune system are also discussed. Based on the knowledge, particles with high antigen payload and optimized attributes could be designed for expected adjuvant purpose, leading to the development of high efficient vaccine candidates.