Skin color-specific and spectrally-selective naked-eye dosimetry of UVA, B and C radiations.

Spectrally-selective monitoring of ultraviolet radiations (UVR) is of paramount importance across diverse fields, including effective monitoring of excessive solar exposure. Current UV sensors cannot differentiate between UVA, B, and C, each of which has a remarkably different impact on human health. Here we show spectrally selective colorimetric monitoring of UVR by developing a photoelectrochromic ink that consists of a multi-redox polyoxometalate and an e- donor. We combine this ink with simple components such as filter paper and transparency sheets to fabricate low-cost sensors that provide naked-eye monitoring of UVR, even at low doses typically encountered during solar exposure. Importantly, the diverse UV tolerance of different skin colors demands personalized sensors. In this spirit, we demonstrate the customized design of robust real-time solar UV dosimeters to meet the specific need of different skin phototypes. These spectrally-selective UV sensors offer remarkable potential in managing the impact of UVR in our day-to-day life.

Photomodulation of bacterial growth and biofilm formation using carbohydrate-based surfactants.

Naturally occurring and synthetic carbohydrate amphiphiles have emerged as a promising class of antimicrobial and antiadhesive agents that act through a number of dynamic and often poorly understood mechanisms. In this paper, we provide the first report on the application of azobenzene trans-cis photoisomerization for effecting spatial and temporal control over bacterial growth and biofilm formation using carbohydrate-based surfactants. Photocontrollable surface tension studies and small angle neutron scattering (SANS) revealed the diverse geometries and dimensions of self-assemblies (micelles) made possible through variation of the head group and UV-visible light irradiation. Using these light-addressable amphiphiles, we demonstrate optical control over the antibacterial activity and formation of biofilms against multi-drug resistant (MDR) Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli. To probe the mechanism of bioactivity further, we evaluated the impact of trans-cis photoisomerization in these surfactants on bacterial motility and revealed photomodulated enhancement in swarming motility in P. aeruginosa. These light-responsive amphiphiles should attract significant interest as a new class of antibacterial agents and as investigational tools for probing the complex mechanisms underpinning bacterial adhesion and biofilm formation.

Development of novel amphiphilic magnetic molecularly imprinted polymers compatible with biological fluids for solid phase extraction and physicochemical behavior study.

In the present work, a novel amphiphilic magnetic molecularly imprinted polymer (M-MIP) has been synthesized by a simple non covalent method for the loading of gatifloxacin (GTFX) in polar solvent. This nanomaterial used as sorbent has been applied to the solid phase extraction of GTFX in different spiked biological fluids. For the first time, studies of dispersibility and solubility behaviors with different solvents and water were performed to demonstrate amphiphilicity and also to find the better nanomaterial obtained. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray (XRD) were used to characterize the nanomaterials, and Scatchard plot analysis to demonstrate the binding kinetic. Results suggest that the dispersibility, solubility and the adsorption in water have relationships with the structure of nanomaterials prepared. The oleic acid coated on the M-MIP combined with the washing process has enhanced the amphiphilicity of the nanomaterials. The M-MIP2 showed better selectivity and adsorption behavior with imprinted efficiency higher than (2) in water, as well as in biological fluids. Moreover, no interference with constituents of blank urine and blank serum samples for solid phase extraction (SPE) was observed. Moreover, loading recovery was found higher than 95% with low RSD. The novel amphiphilic magnetic nanomaterial prepared here as sorbent is suitable for SPE of GTFX in biological fluids for therapeutic monitoring control. It could be also used as carrier in drug delivery system for experimental and clinical studies.

Loading behavior of gatifloxacin in urine and lake water on a novel magnetic molecularly imprinted polymer used as extraction sorbent with spectrophotometric analysis.

The loading behavior of gatifloxacin (GTFX) in human urine and lake water on a novel magnetic molecularly imprinted polymer used as extraction sorbent with UV-Visible spectrometric analysis has been studied. The magnetic polymers had been prepared using GTFX as template molecule and Fe3O4 as magnetic component. The polymer had been characterized by SEM, Fourier-transform infrared spectrometry, and appropriate magnet separator. Parameters affecting the extraction efficiency were evaluated in order to achieve optimal loading and reduce nonspecific interactions. Good linearity of the method had been obtained in the range between 0.25 and 15 µg mL(-1) by UV-Vis spectrophotometry at 286 nm with spectral analysis from 240 to 400 nm. The method detection and quantification limits of GTFX in water were 0.075 and 0.25 µg mL(-1), respectively. This study showed good selectivity and loading efficiency (α > 2) of the polymers. The loading behavior of GTFX in the samples spiked on polymers had been obtained and each other with recovery higher than 91% with RSD% between 2.5 and 3.3. No pretreatment of samples were needed and no interference of compounds in urine and lake water were observed during adsorption.

Anticancer loading and controlled release of novel water-compatible magnetic nanomaterials as drug delivery agents, coupled to a computational modeling approach.

The preparation, characterization and application of novel anticancer "epirubicin" (EPI) water-compatible magnetic molecularly imprinted polymers (M-MIPs) like artificial antibodies by computational design and chemical synthesis as a carrier for drug delivery is described herein. Two monomers: methacrylic acid (MAA) and methacrylamide (MAM) were selected by computational simulation from the four chemicals used. Covalent and non-covalent bonds were evaluated by this technique based on the interaction mode and energy with template or solvent. Non-covalent bonding was predominant in all cases and major energy interaction was observed. The nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and a vibrating sample magnetometer (VSM). The loading and controlled release studies performed showed a slight advantage for the M-MIP obtained from MAA than that from MAM at ambient temperature. However, the drug release in vitro was slightly better for the second M-MIP when the temperature increased to 50 °C. The water-compatible nanomaterial showed good pH-sensitive drug release profiles in vitro. Briefly, due to its magnetic property, amphiphilicity, good biomimetic recognition of EPI, high adsorption capacity and controlled release, the epirubicin M-MIPs synthesized in this study are suitable to be applied to a magnetic targeted drug delivery system.