Construction of a double-increasing emission fluorescent probe and its application in food detection of benzoyl peroxide and biosystem imaging.

In this work, based on the Förster resonance energy transfer (FRET) mechanism strategy, a new dual-increasing emission proportional near-infrared (NIR) fluorescent probe Lay-1 was designed for fast benzoyl peroxide (BPO) detection in real food samples and biosystems. Specifically, it employed a naphthylimide derivative and a NIR fluorophore dicyanoisophorone derivative as the energy transfer donor and acceptor, respectively, and a phenylboronic acid (Ph-B(OH)2) as the responding group of BPO. In addition, the results exhibited that the fluorescence color of Lay-1 was changed from red to orange in the absence and the presence of BPO with a fast response time (∼120 s), high sensitivity, and an excellent limit of detection as low as 60.8 nM. Impressively, Lay-1 has been successfully used for BPO detection in real food samples and biosystems with satisfactory results. Therefore, Lay-1 can be a robust molecular tool to further investigate the physiological and pathological function of BPO.

Biofilm Removal by Reversible Shape Recovery of the Substrate.

Bacteria can colonize essentially any surface and form antibiotic resistant biofilms, which are multicellular structures embedded in an extracellular matrix secreted by the attached cells. To develop better biofilm control technologies, we recently demonstrated that mature biofilms can be effectively removed through on-demand shape recovery of a shape memory polymer (SMP) composed of tert-butyl acrylate (tBA). It was further demonstrated that such a dynamic substratum can sensitize the detached biofilm cells to antibiotics. However, this SMP can undergo shape change only once, limiting its application in long-term biofilm control. This motivated the present study, which aimed to prove the concept that biofilm can be effectively removed by repeated on-demand shape recovery. Reversible shape memory polymers (rSMPs) containing poly(ε-caprolactone) diisocyanatoethyl dimethacrylate (PCLDIMA) of varying molecular masses and butyl acrylate (BA) as a linker were synthesized by using benzoyl peroxide (BPO) as a thermal initiator. By comparison of several combinations of PCLDIMA of different molecular masses, a 2:1 weight ratio mixture of 2000 and 15000 g/mol PCLDIMA was the most promising because it had a shape transition (at 36.7 °C) close to body temperature. The synthesized rSMP demonstrated good reversible shape recovery and up to 94.3 ± 1.0% removal of 48 h Pseudomonas aeruginosa PAO1 biofilm cells after three consecutive shape recovery cycles. Additionally, the detached biofilm cells were found to be 5.0 ± 1.2 times more susceptible to 50 µg/mL tobramycin than the static control.

Optical Properties of Composites Based on Graphene Oxide and Polystyrene.

In this work, new optical properties of composites based on polystyrene (PS) microspheres and graphene oxide (GO) are reported. The radical polymerization of styrene in the presence of benzoyl peroxide, pentane and GO induces the appearance of new ester groups in the PS macromolecular chains remarked through an increase in the absorbance of the infrared (IR) band at 1743 cm-1. The decrease in the GO concentration in the PS/GO composites mass from 5 wt.% to 0.5 wt.% induces a diminution in the intensities of the D and G Raman bands of GO simultaneous with a down-shift of the D band from 1351 to 1322 cm-1. These variations correlated with the covalent functionalization of the GO layers with PS. For the first time, the photoluminescent (PL) properties of PS/GO composites are reported. The PS microspheres are characterized by a PL band at 397 nm. Through increasing the GO sheets' concentration in the PS/GO composite mass from 0.5 wt.% to 5 wt.%, a PS PL quenching process is reported. In addition, in the presence of ultraviolet A (UVA) light, a photo-degradation process of the PS/GO composite having the GO concentration equal to 5 wt.% is demonstrated by the PL studies.

An update on formulation strategies of benzoyl peroxide in efficient acne therapy with special focus on minimizing undesired effects.

Benzoyl peroxide (BPO) in the form of over the counter monotherapeutics or prescription-only combinations is a key component of topical acne therapy, but its unfavourable side effect profile reduces the therapeutic value of this compound. Various galenic approaches have been pursued to resolve this ambivalence, but only a few have managed to enter the market. This article aims to give a comprehensive overview of the published experimental vehicle systems and to identify the fundamental rationales. With regard to the formulation, an increase in the tolerability of BPO can essentially be achieved by combining BPO with re-fattening and moisturizing substances, by incorporating it and controlling its release, as well as by targeted deposition of the active ingredient at the site of action, i.e. drug targeting. Recently, novel particulate formulations have been proposed that combine several of these design principles and are expected to bring new developments in this dynamic field of research.

Acid promoted radical-chain difunctionalization of styrenes with stabilized radicals and (N,O)-nucleophiles.

A difunctionalization of alkenes through sequential addition of a radical and a nucleophile has been developed, which is suggested to proceed by a radical chain mechanism not requiring a catalyst. An electron transfer step to the oxidant benzoyl peroxide is facilitated by protonation with a strong acid.

A selective cascade reaction-based probe for colorimetric and ratiometric fluorescence detection of benzoyl peroxide in food and living cells.

A novel colorimetric and ratiometric fluorescent probe (Cou-BPO) was readily prepared for specific detection of harmful benzoyl peroxide (BPO). The probe Cou-BPO reacted with BPO via a selective oxidation cleavage-induced cascade reaction of the pinacol phenylboronate group, which resulted in an observable colorimetric and ratiometric fluorescence response towards BPO with a fast response time (<15 min) and a low detection limit (56 nM). For practical application, facile, portable and sensitive test paper of Cou-BPO has been prepared for visual detection of BPO. Furthermore, we employed Cou-BPO as a probe to determine BPO in food samples and living cells.

Molecular Surface Functionalization of Carbon Materials via Radical-Induced Grafting of Terminal Alkenes.

Formation of functional monolayers on surfaces of carbon materials is inherently difficult because of the high bond strength of carbon and because common pathways such as SN2 mechanisms cannot take place at surfaces of solid materials. Here, we show that the radical initiators can selectively abstract H atoms from H-terminated carbon surfaces, initiating regioselective grafting of terminal alkenes to surfaces of diamond, glassy carbon, and polymeric carbon dots. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) demonstrate formation of self-terminating organic monolayers linked via the terminal C atom of 1-alkenes. Density functional theory (DFT) calculations suggest that this selectivity is at least partially thermodynamic in origin, as significantly less energy is needed to abstract H atoms from carbon surfaces as compared to typical aliphatic compounds. The regioselectivity favoring binding to the terminal C atom of the reactant alkenes arises from steric hindrance encountered in bond formation at the adjacent carbon atom. Our results demonstrate that carbon surface radical chemistry yields a versatile, selective, and scalable approach to monolayer formation on H-terminated carbon surfaces and provide mechanistic insights into the surface selectivity and regioselectivity of molecular grafting.

A Randomized Controlled Tolerability Study to Evaluate Reformulated Benzoyl Peroxide Face Washes for Acne Vulgaris

Introduction: This randomized, evaluator-blind, single-center, parallel-group study sought to evaluate the tolerability of two reformulated face washes containing benzoyl peroxide (BPO) in adults with mild to moderate acne vulgaris. Methods: Healthy adults with mild to moderate acne vulgaris were randomly allocated (1:1:1) to one of two reformulated test products (containing BPO at a concentration of either 4% or 10%) or an older formulation containing 10% BPO (reference product), which they applied twice daily for 21±2 days. The primary tolerability assessment was clinical assessment of signs and symptoms of cutaneous irritation by a dermatologist. The primary outcome was the total dermatologist assessment score (maximum total assessment score=12, indicating the most severe skin irritation). Secondary assessments were ophthalmologist assessments, subject self-assessments, and adverse events. Results: 133 adults were randomized and treated. The total dermatologist score changed by a mean of -0.08 (95% confidence interval [CI] -0.192, 0.038) from baseline to day 21 in the 4% BPO cleanser group, by 0.05 (95% CI -0.021, 0.121) in the 10% BPO cleanser group, and by -0.02 (95% CI -0.105, 0.059) in the reference product group. There was no clinically significant difference between the reference product and the 4% BPO cleanser or 10% BPO cleanser in the mean change from baseline. Mean changes from baseline in ophthalmologist assessment scores and subject self-assessment scores for the 4% and 10% BPO test products were also comparable to those of the reference product. Dermal responses were consistent with the known effects of topical BPO application and no serious safety issues were reported. Discussion: There was no difference in the local tolerance profile of the reformulated BPO-containing face washes when compared with an older formulation. Study registration: www.gsk-clinicalstudyregister.com (study 206239). J Drugs Dermatol. 2019;18(4):350-356

Incorporation of benzoyl peroxide nanocrystals into adapalene-loaded solid lipid microparticles: Part I - Nanocrystalline benzoyl peroxide.

Hair follicles are a promising target for the administration of drugs to treat diseases associated with the pilosebaceous unit, such as acne. For solid lipid microparticle dispersions a successful and selective delivery of adapalene via targeted erosion of the particles in sebum has been shown. By embedding nanoparticulate benzoyl peroxide in lipid microparticles, the therapeutic potency of adapalene can be further increased by improving follicular deposition of benzoyl peroxide and minimizing direct contact between benzoyl peroxide and stratum corneum, which is responsible for the irritating potential of this active agent. The aim of this study was to develop a novel nanoparticulate formulation for benzoyl peroxide suitable for the incorporation in solid lipid microparticles. In this contribution, a wet grinding process using liposomal dispersions of fully hydrated phosphatidylcholine was developed, upscaled and optimized for solid content and stabilizer concentration. The resulting novel nanosuspension was characterized by particle size and morphology and examined for chemical and physical stability as well as solubility and polymorphism. During the process development a dependency between the colloidal microstructure of the stabilizer dispersion and milling efficiency was found: while physical mixtures fail to deliver nanosuspensions, liposomal dispersions succeed with the same amount of stabilizer.

Topical Vehicle Formulations in the Treatment of Acne.

Topical treatment is the mainstay of acne therapy. The most commonly prescribed topical medications for acne include benzoyl peroxide, clindamycin, and retinoids. Despite their effectiveness in treating mild to moderate acne vulgaris, these topical medications are found to be irritating, and are historically associated with poor tolerability and diminished patient adherence. Thus, choosing the right formulation that will be effective and well tolerated is essential. Novel formulations that optimize drug concentration and utilize improved delivery vehicles have helped to enhance the tolerability and efficacy, and allow for less frequent application or co-application of drugs that were previously considered incompatible. This article will review the goals of topical therapy for the treatment of acne, in addition to common therapies and their challenges. Advanced formulations and combination formulations of benzoyl peroxide, clindamycin, and tretinoin will also be discussed. J Drugs Dermatol. 2018;17(6 Suppl):s6-10.

Clinical evidence for washing and cleansers in acne vulgaris: a systematic review.

PURPOSE: Washing and over-the-counter cleansers are common interventions in acne vulgaris (AV), but the clinical evidence for their benefit is poorly understood. This systematic review presents clinical studies of washing and cleanser efficacy in acne vulgaris to guide treatment recommendations of dermatologists. MATERIALS AND METHODS: We surveyed English-language articles indexed in MEDLINE (1951-March 2017) and EMBASE (1974-March 2017). Articles were required to be prospective studies of a single over-the-counter cleanser or washing intervention in AV with an objective AV outcome measurement published in a peer-reviewed journal. RESULTS AND CONCLUSIONS: Fourteen prospective studies representing 671 participants were included in this review. Modalities investigated included face washing frequency, true soap/syndet cleansing bars, antiseptic cleansers, alpha and beta-hydroxy (i.e. salicylic) acid cleansers, and several proprietary formulations. Given the low number of well-performed clinical studies of cleansers and washing, it is difficult to formulate reliable recommendations. We hope that our findings highlight the necessity of further investigation in this area.

Preparation and biocompatibility of crosslinked poly(3-hydroxyundecenoate).

A sticky polymer, poly(3-hydroxyundecenoate) (PHU), was produced by Pseudomonas oleovorans when nonanoate and undecenoate were used as carbon sources. Crosslinked PHU (CL-PHU) was prepared by heating using benzoyl peroxide as a crosslinker. According to the degree of crosslinking in the polymer, three types of CL-PHU were prepared: CL-PHU50, CL-PHU60 and CL-PHU70. Fourier transform-infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry results suggested that crosslinking of PHU was successfully achieved by heat, which increased the crosslinking density and decreased stiffness and flexibility of the polymer. Water contact angle measurements revealed no differences of hydrophilicity as the crosslinking density. Slight morphological changes of CL-PHU film surfaces were observed by atomic force microscopy. Chinese hamster ovary cells were used to investigate the biocompatibility of CL-PHU films using poly(l-lactide) surfaces as control. Surface properties of the film, such as roughness and adhesive force, enhanced the adhesion and proliferation of cells on the films. CL-PHU might be useful for cell compatible biomedical applications.

Spectrofluorimetric determination of atenolol from human urine using high-affinity molecularly imprinted solid-phase extraction sorbent.

This study presents a novel, sensitive and selective molecularly imprinted solid-phase extraction (MISPE)-spectrofluorimetric method for the removal and determination of atenolol from human urine. Molecularly imprinted and non-imprinted polymers were synthesized thermally using a radical chain polymerization technique and used as solid-phase extraction sorbents. Acrylic acid ethylene glycol dimethacrylate, dibenzoyl peroxide and dichloroethane were used as a functional monomer, cross-linker, initiator and porogen, respectively. The calibration curve was in the range of 0.10-2.0 µg/ml for the developed method. Limit of detection and limit of quantification values were 0.032 and 0.099 µg/ml, respectively. Owing to the selectivity of the MISPE technique and the sensitivity of spectrofluorimetry, trace levels of atenolol have been successfully determined from both organic and aqueous media. Relatively high imprinting factor (4.18) and recovery results (74.5-75.3%) were obtained. In addition, intra- and interday precision values were 0.38-1.03% and 0.47-2.05%, respectively, proving the precision of the proposed method. Thus, a selective, sensitive and simple MISPE-spectrofluorimetric method has been developed and applied to the direct determination of atenolol from human urine.

Benzoyl Peroxide as an Efficient Dopant for Spiro-OMeTAD in Perovskite Solar Cells.

Although organic small molecule spiro-OMeTAD is widely used as a hole-transport material in perovskite solar cells, its limited electric conductivity poses a bottleneck in the efficiency improvement of perovskite solar cells. Here, a low-cost and easy-fabrication technique is developed to enhance the conductivity and hole-extraction ability of spiro-OMeTAD by doping it with commercially available benzoyl peroxide (BPO). The experimental results show that the conductivity increases several orders of magnitude, from 6.2×10-6  S cm-1 for the pristine spiro-OMeTAD to 1.1×10-3  S cm-1 at 5 % BPO doping and to 2.4×10-2  S cm-1 at 15 % BPO doping, which considerably outperform the conductivity of 4.62×10-4  S cm-1 for the currently used oxygen-doped spiro-OMeTAD. The fluorescence spectra suggest that the BPO-doped spiro-OMeTAD-OMeTAD layer is able to efficiently extract holes from CH3 NH3 PbI3 and thus greatly enhances the charge transfer. The BPO-doped spiro-OMeTAD is used in the fabrication of perovskite solar cells, which exhibit enhancement in the power conversion efficiency.

Deciphering the intercalative binding modes of benzoyl peroxide with calf thymus DNA.

The binding of benzoyl peroxide (BPO), a flour brightener, with calf thymus DNA (ctDNA) was predicted by molecular simulation, and this were confirmed using multi-spectroscopic techniques and a chemometrics algorithm. The molecular docking result showed that BPO could insert into the base pairs of ctDNA, and the adenine bases were the preferential binding sites which were validated by the analysis of Fourier transform infrared spectra. The mode of binding of BPO with ctDNA was an intercalation as supported by the results from ctDNA melting and viscosity measurements, iodide quenching effects and competitive binding investigations. The circular dichroism and DNA cleavage assays indicated that BPO induced a conformational change from B-like DNA structure towards to A-like form, but did not lead to significant damage in the DNA. The complexation was driven mainly by hydrogen bonds and hydrophobic interactions. Moreover, the ultraviolet-visible (UV-vis) spectroscopic data matrix was resolved by a multivariate curve resolution-alternating least-squares algorithm. The equilibrium concentration profiles for the components (BPO, ctDNA and BPO-ctDNA complex) were extracted from the highly overlapping composite response to quantitatively monitor the BPO-ctDNA interaction. This study has provided insights into the mechanism of the interaction of BPO with ctDNA and potential hazards of the food additive.

Polymeric micellar nanocarriers of benzoyl peroxide as potential follicular targeting approach for acne treatment.

The aim of this work was to optimize polymeric nano-sized micellar carriers of the anti-acne compound benzoyl peroxide (BPO) and to examine the ability of these carriers to deposit into hair follicles with the objective of improving skin delivery of BPO. BPO loaded polymeric micelles composed of Pluronic(®) F127 were prepared by the thin film hydration method and characterized in terms of size, loading capacity, morphology and physical stability. The optimized micelle formulation was then selected for skin delivery studies. The penetration of BPO loaded micellar carriers into skin and skin appendages across full thickness porcine skin was examined in vitro. Confocal microscopy images confirmed the penetration of Nile Red into hair follicles, which was loaded into micellar carriers as a model fluorescent compound. The relative safety of the polymeric micelles was evaluated with the MTT viability test using mouse embryonic fibroblasts. The results indicated that nano-sized polymeric micelles of BPO composed of Pluronic(®) F127 offer a potential approach to enhance skin delivery of BPO and that targeting of micelles into hair follicles may be an effective and safe acne treatment.

Multi-Walled Carbon Nanotube Functionalization by Radical Addition Using Hydroxymethylene Groups.

Synthetic methodology and characterization of multi-walled carbon nanotubes (MWCNTs) function- alized with hydroxymethylene groups are reported. The MWCNTs were synthesized by the spray pyrolysis technique using toluene as carbon source and ferrocene as catalyst. Hydroxymethylation of MWCNTs was carried out by methanol using benzoyl peroxide (BPO) at different quantities (300 to 900 mg); the optimum BPO quantity was 300 mg. The resulting materials were characterized by FT-IR, Raman Spectroscopy, Thermal Gravimetric Analysis (TGA) and Transmission Electron Microscopy (TEM). The presence of the hydroxymethylene group on the MWCNTs surface was demonstrated by FT-IR, Raman Spectroscopy, TGA, EDS, TEM and Mass Spectrometry. The func- tionalized MWCNTs were not damaged by this methodology.

Molecular Oxygen and Reactive Oxygen Species in Bread-making Processes: Scarce, but Nevertheless Important.

In bread making, O2 is consumed by flour constituents, yeast, and, optionally, some additives optimizing dough processing and/or product quality. It plays a major role especially in the oxidation/reduction phenomena in dough, impacting gluten network structure. The O2 level is about 7.2 mmol/kg dough, of which a significant part stems from wheat flour. We speculate that O2 is quickly lost to the atmosphere during flour hydration. Later, when the gluten network structure develops, some O2 is incorporated in dough through mixing-in of air. O2 is consumed by yeast respiration and in a number of reactions catalyzed by a wide range of enzymes present or added. About 60% of the O2 consumption in yeastless dough is ascribed to oxidation of fatty acids by wheat lipoxygenase activity. In yeasted dough, about 70% of the O2 in dough is consumed by yeast and wheat lipoxygenase. This would leave only about 30% for other reactions. The severe competition between endogenous (and added) O2-consuming systems impacts the gluten network. Moreover, the scarce literature data available suggest that exogenous oxidative enzymes but not those in flour may promote crosslinking of arabinoxylan in yeastless dough. In any case, dough turns anaerobic during the first minutes of fermentation.