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Coating gold nanorods (AuNRs) with different materials, such as polymers and graphene-based materials, has improved their biocompatibility. However, these materials have been shown to cause the instability of AuNRs in thermal and culture mediums. In addressing this issue, we herein report the synthesis, thermal and culture medium stability, and photothermal profiling of Polyvidone (PVP)-modified graphene oxide (GO)-coated AuNRs (mGO@AuNRs). The AuNRs, with a size of 40.70 nm × 9.16 nm and absorbing at 820 nm, were coated with PVP, GO, and mGO. The colloidal stability of the nanocomposites was tested in three commonly used cell culture mediums: the Roswell Park Memorial Institute 1640 (RPMI-1640), Dulbecco's Modified Eagle Medium, (DMEM) and Dulbecco's phosphate-buffered saline (PBS) using UV-Vis-NIR and dynamic light scattering. The GO-based nanocomposites were stable compared to PVP@AuNRs and AuNRs in all mediums. The photothermal profiling of mGO@AuNRs showed higher heat production, with the photothermal conversion efficiency of 54.8%, which is higher than the bare AuNRs, GO@AuNRs, and PVP@AuNRs. In addition, the mGO@AuNRs also showed good thermal stability at 70 °C for more than 24 h. These results present the dual coating of PVP and GO as excellent stabilising agents for AuNRs with good photothermal profiling. [ABSTRACT FROM AUTHOR]

Photothermal application of gold nanorods (AuNRs) is widely increasing because of their good photothermal conversion efficiency (PCE) due to local surface plasmon resonance. However, the high concentration of hexadecyltrimethylammonium bromide used in the synthesis is a concern. Moreover, the mild and commonly used reducing agent-ascorbic acid does not reduce the Au(I) to A(0) entirely, resulting in a low yield of gold nanorods. Herein we report for the first time the PCE of large-scaled synthesized AuNRs using the binary surfactant seed-mediated method with hydroquinone (HQ) as the reducing agent. The temporal evolution of the optical properties and morphology was investigated by varying the Ag concentration, HQ concentration, HCl volumes, and seed solution volume. The results showed that the seed volume, HQ concentration, and HCl volume played a significant role in forming mini-AuNRs absorbing in the 800 nm region with a shape yield of 87.7%. The as-synthesized AuNRs were successfully up-scaled to a larger volume based on the optimum synthetic conditions followed by photothermal profiling. The photothermal profiling analysis showed a temperature increase of more than 54.2 °C at 2.55 W cm−2 at a low optical density (OD) of 0.160 after 630 s irradiation, with a PCE of approximately 21%, presenting it as an ideal photothermal agent. [ABSTRACT FROM AUTHOR]

We herein report a novel eco-friendly method for the fluorescent sensing of Cr (III) ions using green synthesized glutathione (GSH) capped water soluble AgInS2-ZnS (AIS-ZnS) quantum dots (QDs). The as-synthesized AIS-ZnS QDs were speherical in shape with average diameter of ∼2.9 nm and exhibited bright yellow emission. The fluorimetric analyses showed that, compared to Cr (VI) ions and other 20 metal ions across the periodic table, AIS-ZnS QDs selectively detected Cr (III) ions via fluorescent quenching. In addition, AIS-ZnS QDs fluorescent nanoprobes exhibited selective detection of Cr (III) ions in the mixture of interfering divalent metal ions such as Cu (II), Pb (II), Hg (II), Ni (II). The mechanism of Cr (III) sensing investigated using HRTEM and FTIR revealed that the binding of Cr (III) ions with the GSH capping group resulted in the aggregation of QDs followed by fluorescence quenching. The limit of detection of Cr (III) ions was calculated to be 0.51 nM. The present method uses cadmium free QDs and paves a greener way for selective determination of Cr (III) ions in the midst of other ions in aqueous solutions. [ABSTRACT FROM AUTHOR]

Hexadecylamine (HDA) capped CdSe/ZnSe core/shell and ZnxCd1−xSe alloy quantum dots (QDs) have been synthesized successfully via a non-organometallic, hot injection method. The optical, structural and morphological properties of the as-synthesized QDs were determined by using, UV-visible (UV-Vis) and photoluminescence spectroscopy, X-ray diffraction and transmission electron microscopy (TEM). The effect of reaction time and temperature on the core/shell and alloy formation were investigated in detail. The addition of ZnSe precursor to the pre-synthesized HDA capped CdSe QDs at 230 °C produced core/shell CdSe/ZnSe QDs whereas at 250 °C an alloy QDs were obtained initially which later transformed to core/shell structure with time. On the other hand, the immediate addition of ZnSe precursor to the hot CdSe-precursor solution in HDA at 230 °C resulted in HDA capped ZnxCd1−xSe alloy QDs. The optical and structural characterisation shows that the as-synthesised core-shell and alloy QDs are of high quality. This method is simple, and fast for the preparation of core/shell and alloy binary QDs and will encourage their synthesis for various industrial applications. [ABSTRACT FROM AUTHOR]

The regular diet of common man is often deficient in certain nutrients, so dietary supplements are commonly prescribed. In this study, a combination of vitamins and minerals in the form of a bilayer tablet is proposed as a dietary supplement. A film-coated bilayer tablet in which one layer contains premixed vitamins (A, D, E, C, B1, B2, B3, B5, B6, B7, B9 and B12) and the other layer contains premixed minerals (magnesium, manganese, molybdenum, iodine, zinc, silicon and copper) was formulated by direct compression method. This uniquely formed bilayer tablet was assessed for physiochemical properties, microbial load and stability studies. FTIR studies revealed that there was no interaction between the vitamins, minerals and excipients used in the study. In vitro dissolution test revealed that >85% of folic acid and zinc sulphate were released in 60 min at pH 6.5–7.5. The release of folic acid was found to follow a first-order and Higuchi model, whereas zinc sulphate followed a first-order and Korsemeyer-Peppas model, indicating diffusion and erosion mechanism. The results of the long term and accelerated stability studies showed that, there were no changes in physicochemical properties and release pattern of bilayer tablets. Furthermore, the optimized formulation showed increase in the stability period for about 24 months. This nutritional supplement based on oral delivery of bilayer tablets is expected to gain more acceptance among the commercially available products due to better release properties and combination therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] • A green-emitting N,S-CQDs fluorescent probe was developed for sensing of Hg2+ ions. • The synthesis was achieved hydrothermally using CA, glutamine and Na 2 S as precursors. • The N,S-CQDs showed selectivity towards Hg2+ with a LOD of 28.9 nM. • Application as nanoprobe in Oreochromis niloctus showed excellent reliability. This study reported the synthesis of green-emitting N,S-doped carbon quantum dots (N,S-CQDs) through a one-step, facile, and fast hydrothermal technique using citric acid, glutamine, and Na 2 S as the carbon, nitrogen, and sulphur sources respectively. The fluorescence efficiency of the developed nanosensor was investigated by varying the duration of synthesis (4, 5, and 6 h). Characterization of the N-CQDs was achieved using Fourier-Transform Infra-red Spectroscopy (FTIR), High-resolution transmission electron microscope (HRTEM), ultraviolet–visible spectroscopy (UV–Vis), and X-Ray diffraction analysis (XRD). The as-synthesized N,S-CQDs are small (average size of 3.45 ± 0.86 nm), spherical, and displayed green emission (535 nm) with a fluorescent quantum yield (QY) of 10.35%. FTIR analysis reveals carboxylic, hydroxyl, and conjugated amide functional groups. The fluorometric study showed that the developed nanosensor was selective and sensitive towards Hg2+ ions in the midst and absence of interfering ions with a detection limit (LOD) of 28.9 nM. The static quenching mechanism was proposed based on lifetime and UV results. Furthermore, it was used as a nanoprobe for Hg2+ determination in Oreochromis niloctus with recoveries of 96.7–108.6% (RSD < 4.1%), indicating the as-synthesized N,S-CQDs have potentials as a nanoprobe for Hg2+ determination in sea foods. [ABSTRACT FROM AUTHOR]

We herein report the synthesis of orange emitting CdSe-polycaprolactone nanofiber via a simple and total phosphine free method. The hexadecylamine (HDA)-capped CdSe NPs was synthesized by dispersing the as-synthesized CdSe cluster in octadecene followed by thermolysis in hexadecylamine in the absence of an inert gas. The as-synthesized CdSe NPs are of good quality with high orange luminescent intensity, narrow emission width and high photostability. The transmission electron microscopy (TEM) micrograph revealed that the particles are small, monodispersed and highly crystalline with an average particle size of 2.67±43 nm. The dispersion of the as-synthesized CdSe NPs in biopolymer polycaprolactone (PCL) produced reddish orange emitting electrospun polymer nanocomposite nanofibers. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is a developing membrane separation technology for water treatment that involves a vapor transport driven by the vapor pressure gradient across the hydrophobic membrane. MD has gained wide attention in the last decade for various separation applications, including the separation of salts, toxic heavy metals, oil, and organic compounds from aqueous solutions. Compared with other conventional separation technologies such as reverse osmosis, nanofiltration, or thermal distillation, MD is very attractive due to mild operating conditions such as low temperature and atmospheric pressure, and 100% theoretical salt rejection. In this review, membrane distillation's principles, recent MD configurations with their advantages and limitations, membrane materials, fabrication of membranes, and their surface engineering for enhanced hydrophobicity are reviewed. Moreover, different types of membrane fouling and their control methods are discussed. The various applications of standalone MD and hybrid MD configurations reported in the literature are detailed. Furthermore, studies on the MD-based pilot plants installed around the world are covered. The review also highlights challenges in MD performance and future directions. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have attracted much attention over the past decades due to their outstanding properties. However, obtaining QDs with excellent photoluminescence and quantum yields (QYs) from their aqueous synthesis is still a big concern. We herein present a green and facile synthesis of AgInS (AIS) QDs and AgInS-ZnS (AIS-ZnS) core-shell QDs using a combination of two capping agents (glutathione and sodium citrate). The temporal evolution of the optical properties is investigated by varying the reaction time and pH of the solution. The results show that the fluorescence intensity of the QDs increases as the reaction time increase, while the emission position blue-shift as the pH of the solution increase. An outstanding photoluminescence quantum yield (PLQY) of 90% is obtained at optimized synthetic conditions. The Fourier transform Infrared studies confirm efficient passivation of the QDs by the capping agents. The XRD analysis reveals that all the materials crystallize in the tetragonal crystalline phase, while the TEM micrographs of AIS-ZnS QDs reveal a spherical shape. The EDS analysis confirms the presence of Silver, Indium, Sulphide, and Zinc elements. The reported synthetic route is facile and eco-friendly. [ABSTRACT FROM AUTHOR]

• We reported two different carbon-based quantum dots (CBQDs). • CBQDs showed good photoluminescence when excited from ultraviolet to near infrared region. • The emission wavelength of CBQDs can be tuned from 420 and 540 nm. • High quantum yields of 45.49 and 44.29% were achieved. • Both CBQDs showed good cell viability towards two different cell lines. We herein report the synthesis of blue and green emitting carbon-based quantum dots (CBQDs). The materials displayed good photoluminescence (PL) emission when excited from ultraviolet (UV) to near infrared (NIR) region and quantum yield of 45.49 and 44.29% for the blue and green CBQDs respectively. The structural characterizations confirmed that the as-synthesized materials are small, spherical in shape and highly crystalline. The cell viability study against mouse colon carcinoma (C26) and mouse bladder carcinoma (MBT-2) cells showed concentration dependent biocompatibility. [ABSTRACT FROM AUTHOR]

• Novel, superhydrophobic PES-ZnO rods composite membrane was prepared. • ZnO rods were grown on PES membrane followed by stearic acid modification. • High surface roughness (395 nm) and excellent contact angle of ~163° were achieved. • Potential material for oil-water separation applications. The development of superhydrophobic membrane has gained more attention. The current methods for superhydrophobic surface mostly involve fluorosilanes as surface modification agent which is expensive and harmful to the environment. We herein report, simple and cost effective, fabrication of novel superhydrophobic polyethersulfone-composite membranes. The superhydrophobicity of the membrane surface was achieved by growing ZnO rods ex-situ followed by modification with stearic acid. SEM results showed the presence of ZnO rods with the length ranging from 1 µm to 11 µm on the membrane surface while AFM results revealed high surface roughness. The as-prepared membrane exhibited high water repellent with contact angle of ~163° and excellent superoleophilicity. The PES-ZnO rod-SA modified membrane could be an excellent candidate for oil-water separation. [ABSTRACT FROM AUTHOR]

Green synthesized magnetic nanoparticles (MNPs) linked with activated charcoal (AC) (AC/Fe 3 O 4 NCs) were exploited for methylene blue (MB) confiscation in this study. The AC/Fe 3 O 4 NCs produced were characterized using TEM, FTIR, UV/Vis and XRD spectrometry. The Response-Surface-Methodology (RSM) was utilized to improve the experimental data for the MB sorption to AC/Fe 3 O 4 NCs, with 20 experimental runs implemented through a central composite design (CCD) to assess the effect of sorption factors-initial MB concentration, pH and sorbent dosage effects on the response (removal-effectiveness). The quadratic model was discovered to ideally describe the sorption process, with an R2 value of 0.9857. The theoretical prediction of the experimental data using the Artificial-Neural-Network (ANN) model showed that the Levenberg-Marquardt (LM) had a better performance criterion. Comparison between the modelled experimental and predicted data showed also that the LM algorithm had a high R2 of 0.9922, which showed NN model applicability for defining the sorption of MB to AC/Fe 3 O 4 NCs with practical precision. The results of the non-linear fitting (NLF) of both isotherm and kinetic models, showed that the sorption of MB to AC/Fe 3 O 4 NCs was perfectly described using the pseudo-second-order (PSOM) and Freundlich (FRHM) models. The estimated optimum sorption capacity was 455 mg g−1. Thermodynamically, the sorption of MB to AC/Fe 3 O 4 NCs was shown to be non-spontaneous and endothermic. [Display omitted] • An optimal sorption capacity of 455 mg g−1 was established from this study. • The PSOM and FRHM adequately define MB confiscation to AC/Fe 3 O 4 NCs. • The quadratic model with an R2 value of 0.9857 perfectly explained the sorption process of MB dye. • The LM best predict the sorption of MB to AC/Fe 3 O 4 NCs with an R2 value of 0.9922. [ABSTRACT FROM AUTHOR]

The synthesis of ZnInS (ZIS) quantum dots (QDs) in aqueous medium using thioglycolic acid (TGA) and sodium citrate as dual capping agents has been reported. The as-synthesized ZIS QDs were water soluble, emitting at 512 nm and nearly spherical in shape with average particle size of 8.9 ± 1.4 nm. The as-synthesized ZIS QDs were tested for its fluorescence response against different metal ions and the results revealed that ZIS QDs were selectively quenched by Co2+ ions compared to other ions. The fluorescence sensing experiment showed that ZIS QDs has a linear response against the concentration of Co2+ ions (0.1–100 μM) with the detection limit of 0.099 μM. Based on the transmission electron microscope and absorption spectroscopy analyzes, the fluorescence quenching is attributed to the formation of surface ligand-metal complex (TGA-Co2+ ions) which caused aggregation of the QDs. The present method explores the synthesis of zero-dimentional ZIS QDs and its potential in the selective detection of Co2+ ions in aqueous solution. [ABSTRACT FROM AUTHOR]

We report the preparation of poly (propylene imine) dendrimer (PPI) and CdTe/CdSe/ZnSe quantum dots (QDs) as a suitable platform for the development of an enzyme-based electrochemical cholesterol biosensor with enhanced analytical performance. The mercaptopropionic acid (MPA)-capped CdTe/CdSe/ZnSe QDs was synthesized in an aqueous phase and characterized using photoluminescence (PL) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), X-ray power diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy. The absorption and emission maxima of the QDs red shifted as the reaction time and shell growth increased, indicating the formation of CdTe/CdSe/ZnSe QDs. PPI was electrodeposited on a glassy carbon electrode followed by the deposition (by deep coating) attachment of the QDs onto the PPI dendrimer modified electrode using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC), and N-hydroxysuccinimide (NHS) as a coupling agent. The biosensor was prepared by incubating the PPI/QDs modified electrode into a solution of cholesterol oxidase (ChOx) for 6 h. The modified electrodes were characterized by voltammetry and impedance spectroscopy. Since efficient electron transfer process between the enzyme cholesterol oxidase (ChOx) and the PPI/QDs-modified electrode was achieved, the cholesterol biosensor (GCE/PPI/QDs/ChOx) was able to detect cholesterol in the range 0.1–10 mM with a detection limit (LOD) of 0.075 mM and sensitivity of 111.16 μA mM−1 cm−2. The biosensor was stable for over a month and had greater selectivity towards the cholesterol molecule. [ABSTRACT FROM AUTHOR]

• Essential minerals are prepared in a coated/adsorbate form to increase stability. • The coated/adsorbate form of minerals was formulated into matrix tablets using HPMC. • SEM analysis of tablet displayed interlocking between trace elements and polymer. • Dissolution of the tablet shows a highly porous network of the polymer matrix. • The in-vitro release shows a sustained release profile with increased stability. Essential minerals play a very important role in maintaining our physical well-being. In this work, essential minerals; copper sulphate, zinc sulphate, selenium dioxide, chromium picolinate, sodium molybdate and potassium iodide were prepared into tablet formulation with enhanced stability. These minerals are prepared in a coated or as an adsorbate form so as to increase the stability of the minerals. The coated/adsorbate form was formulated into matrix tablets using hydroxypropyl methyl cellulose (HPMC) by the direct compression technique. The distinctively formed tablet was assessed for its physicochemical properties, in-vitro release, microbiological and stability studies. SEM analysis showed that the surface topography of the tablet displayed mechanical interlocking between the trace elements and polymer. During dissolution, the hydrated tablet shows highly porous network of the polymer matrix. Afterwards, they undergo surface erosion from the porous network and the trace minerals gets released. The in-vitro release of zinc sulphate with polymer HPMC K4M showed a sustained release behaviour and fits into the first order and Korsemeyer-Peppas model. The formulation of the trace mineral tablet shows a sustained release profile with increased stability. This trace element matrix tablet supplements is expected to gain acceptance than the marketed products owing to its sustained release behaviour. [ABSTRACT FROM AUTHOR]

Camptothecin (CPT) is a potential anticancer drug. However, it faces challenges due to its poor water solubility and the need for an efficient drug release system. Herein, we developed a novel system composed of gelatin stabilized, mesoporous silica SBA15 encapsulated CuInS2/ZnS (CIS/ZnS) quantum dots (QDs) conjugated with β-cyclodextrin (β-CDs) for its potential use in the release of CPT. In this multifunctional system, β-CDs served as the drug carrier, SBA15 encapsulated QDs is capable of imaging and the gelatin was used to enhance the carrier-drug interaction. Fourier transform infrared (FTIR) analysis confirmed the successful conjugation of β-CDs to the Gel-SBA15 CIS/ZnS QDs, while optical analyses revealed excellent emission properties and high photostability. The β-CD-conjugated Gel-SBA15-CIS/ZnS QD nanocomposite was used to obtain the soluble derivate of CPT which further demonstrated a drug release profile following the triphasic model. Overall, the improved photostability and acceptable drug release profile of the β-CD conjugated Gel-SBA15-CIS/ZnS QD nanocomposite hold great promise for both imaging and therapeutic applications. [ABSTRACT FROM AUTHOR]

This study reports the synthesis of magnetic nanoparticles (MNPs) using the co-precipitation method with the support of Vernonia Amygdalina (VA) (bitter leaf) extract for the efficient sequestration of rhodamine 6G dye (Rhd 6G) from a water-soluble solution. The prepared MNPs were characterized using Transmission electron microscopy (TEM,) X-ray Diffraction (XRD), Fourier-transform infrared (FTIR) and Ultraviolet–visible (UV–Vis) spectrometry. The average particle sizes from TEM and XRD analyses were 4.81 ± 2.2 nm and 5.61 nm respectively. The sorption of Rhd 6G dye to the MNPs was pH-dependent, with ideal confiscation of dye molecules observed at pH 10 ( ∼ 91.4 %) . The sorption process of Rhd 6G dye was reported to follow the Freundlich (FRH) isotherm model, while the pseudo-first-order model (PFOM) best depicted the sorption process of Rhd 6G dye to the MNPs from the non-linear modelling. The determined sorption capacity of the MNPs was established to be 454 mg.g−1. Also, the sorption of Rhd 6G dye to the MNPs was observed to be thermodynamically spontaneous, endothermic and with increasing randomness between the interface of the water-soluble solution and the MNPs. Hence, the prepared MNPs have proven to be an effective potential magnetic sorbent for the removal of cationic dyes from an aqueous solution. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) as a coating material for gold nanorods (AuNRs) has gained interest in reducing toxicity and improving the photothermal profiling of AuNRs. However, there is still a challenge regarding the storage of colloidal suspensions of GO-coated AuNRs (GO@AuNRs). Hence, the conjugation of GO@AuNRs to meso-tetra-(4-sulfonatophenyl)porphyrin (TPPS4), an anionic water-soluble porphyrin, has been reported to enhance their re-dispensability and improve their phototherapeutic properties. The AuNRs and GO were synthesised using seed-mediated and Hummers' methods, respectively. The GO@AuNRs were conjugated to TPPS4 and characterised using ultraviolet–visible–near-infrared (UV-Vis-NIR) spectroscopy, zeta analyser, dynamic light scattering (DLS), photoluminescence spectroscopy (PL), x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR) before freeze-drying. The results showed that the AuNRs were sandwiched between GO and TPPS4. After freeze-drying, the freeze-dried conjugate was dispensed in deionised water without adding cryoprotectants and its properties were compared to those of the unfreeze-dried conjugate. The results showed that the freeze-dried conjugate contained similar optical properties to the unfreeze-dried conjugate. However, the bare GO@AuNRs showed a change in the optical properties after freeze-drying. These results revealed that porphyrin is an excellent additive to reduce the freeze-drying stress tolerance of GO@AuNRs. The freeze-dried conjugate also showed both singlet oxygen and photothermal properties of GO@AuNRs and porphyrin. These results indicated that the freeze-dried conjugate is a promising dual photodynamic and photothermal agent, and porphyrin can act as a cryoprotectant. [ABSTRACT FROM AUTHOR]

Antibiotics are commonly used to control, treat or prevent bacterial infections, however bacterial resistance to all known classes of traditional antibiotics has significantly increased in the last decades especially in hospitals rendering certain therapies ineffective. To limit this emerging public health problem there is a need to develop non-invasive, non-toxic and novel antimicrobial strategies that act more efficiently and faster than the current antibiotics, to which pathogens will not easily develop resistance. One of these methods is Antibacterial Photodynamic Therapy (aPDT). This review focuses on the application of porphyrins in the photo-inactivation of bacteria. Mechanisms of bacterial resistance and some of the current ‘greener’ methods of synthesis of meso-phenyl porphyrins are discussed. In addition, significance and limitations of aPDT are also discussed. Furthermore, we also elaborate on the current clinical applications and the future perspectives and directions of this non-antibiotic therapeutic strategy in combating infectious diseases. [ABSTRACT FROM AUTHOR]

A stable chitosan protected tetrasulfonated copper phthalocyanine (Chit-TsCuPc) modified glassy carbon electrode (GCE) was used to aid the electrochemical detection of nitrite (NO 2 − ) in food samples. The electrochemical oxidation of NO 2 − was investigated on bare, chitosan and TsCuPc modified GCE in presence of phosphate buffer solution with an acidic medium. The elevated oxidation peak current was noticed at less oxidation potential for + 0.55 V vs. Ag/AgCl at Chit-TsCuPc modified electrode under the optimized experimental conditions. The plot displays the peak current against NO 2 − with a good linearity in the concentration rangefrom 6.5 × 10 −8  M to 5.0 × 10 −10 M. The linear regression equation is calculated to be I p (μA) = 0.5291 + 1.4894C (NO 2 − ), has a good correlation coefficient of 0.9949 and the detection limit of 22 nM (S/N = 3) with the current sensitivity of 4.964 μA nM −1  cm −2 . The standard addition method was adopted to measure the unknown NO 2 − concentration in food samples. [ABSTRACT FROM AUTHOR]

The photothermal application of gold nanorods (AuNRs) as a photothermal agent has gained popularity due to their optical, photothermal and biological properties. However, AuNRs are synthesised using a biotoxic surfactant (cetyl trimethyl ammonium bromide) which limits their biological applications. Though different techniques have been established to address this challenge using different stabilizers or passivating agents, the effect of these stabilizers on AuNRs' colloidal stability, thermal stability, and photothermal conversion efficiency still need to be investigated. In this study, we evaluated the effect of different polymers or stabilisers; two synthetic polymers [methoxy polyethylene glycol thiol (mPEG-SH) and polyvinylpyrrolidone (PVP)] and one biopolymer (gelatin) on the stability and photothermal properties of AuNRs. AuNRs absorbing around 800 nm were synthesised and coated with these three stabilisers. The colloidal stability of the as-synthesised material was evaluated in Dulbecco's phosphate-buffered saline (PBS) and Roswell Park Memorial Institute (RPMI-1640) using Ultraviolet–Visible–Near-Infrared (UV–Vis–NIR). The results show that PEG@AuNRs was more stable in both media due to fewer functional groups on its structure to bond with ions and protein. PVP@AuNRs showed good thermal stability under heat incubation (at 37, 50 and 70 °C) for 24 h because of its high thermal decomposition properties, while PEG@AuNRs proved superior in improving the AuNRs heat generation. In addition, coating with different polymers did not affect the photothermal ability of AuNRs. This study demonstrated that it is crucial to choose polymers with less functional groups when coating nanoparticles for biological application. [ABSTRACT FROM AUTHOR]

We herein report an aqueous synthesis of gelatin stabilized CdTe/CdS/ZnS (CSSG) core/double shell quantum dots (QDs) with improved biocompatibility. The as-synthesized QDs were characterized by ultraviolet-visible (UV–vis) and photoluminescence (PL) spectroscopic techniques, x-ray diffraction technique (XRD), x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The CSSG QDs revealed high photoluminescence quantum yield (PLQY) with excellent stability over a period of one year and retained 90% of its initial PLQY without any aggregation or precipitation under ambient condition. The cell viability study conducted on HeLa, cervical cancer cell lines indicated that the gelatin stabilization effectively decreased the QDs cytotoxicity by about 50%. The CSSG QDs were conjugated with transferrin (Tf) for the efficient delivery to the cancer cells followed by fluorescence imaging. The results showed that the CSSG QDs illuminates the entire cell which renders the QDs as cell labeling markers. The gelatin stabilized core/double shell QDs are potential candidates for long time fluorescent bio-imaging. [ABSTRACT FROM AUTHOR]

We present an efficient and effective method for preparing a novel self-assembled nanostructured material with high toughness and impact strength from a blend of di-glycidyl ether of bisphenol-A (DGEBA) and epoxidized poly(styrene-block-butadiene-block-styrene) (eSBS55) tri-block copolymer. The field emission scanning electron microscopy and transmission electron microscope results show the nanostructured morphological characteristics of the blends. This study achieved the highest fracture toughness, with a fracture toughness in the form of critical stress intensity factors (KIC) value of 2.54 MPa m1/2, in epoxy/block copolymer blends compared to previous works in the field. The impact strength also increased by 116% compared to neat epoxy. This is a major advancement in epoxy toughening due to the use of a single secondary phase. The resulting highly tough and impact-resistant material is a promising candidate for coating applications in industries such as flooring, building, aerospace, and automobiles. [ABSTRACT FROM AUTHOR]

In the present work, we report a simple synthetic strategy for fabricating ZnCuInS/ZnS–TPPS4 conjugates and study its cytotoxicity as a promising material for imaging and phototherapy applications. The quaternary QDs were synthesized using eco-friendly materials such as glutathione and water as a solvent, while the anionic 10,15,20-(4-sulphonatophenyl) porphyrin (TPPS4) was synthesized via the acidification of a meso-tetraphenylporphyrin precursor. Interest in TPPS4 results from its high-water dispersity, stability, and ability to generate singlet oxygen. Conjugation of ZnCuInS/ZnS QDs with TPPS4 was performed by titrating porphyrin with different amounts of ZnCuInS/ZnS QDs while keeping all other experimental parameters constant. Comparative analysis of the conjugate to the bare QDs and porphyrin revealed enhanced spectral and photophysical properties. Comparative cytotoxicity assays were performed for TPPS4 and ZnCuInS/ZnS–TPPS4 conjugates in BHK21, Hela, A549, Hek 293 and B16-F10 Nex 2 cell lines using the MTT cell viability assay. The results showed negligible in vitro cytotoxicity indicating the conjugate is an excellent and biocompatible candidate for imaging and phototherapy applications. [ABSTRACT FROM AUTHOR]

Ternary quantum dots (QDs) are promising inorganic fluorescent probes, especially for bioimaging and optical detection. However, the long-term stability and photostability of these QDs are still challenging. We herein report the synthesis of gelatin (Gel) stabilized mesoporous silica-(Santa Barbara Amorphous (SBA 15)) encapsulated CuInS2/ZnS quantum dots- (SBA-QDs) and its cell viability against A549 and Hela cell lines. The as-synthesized Gel-SBA-QDs composites exhibited improved quantum yield (QY) and high photostability. FTIR spectroscopy and surface charge analysis confirmed the effective capping of gelatin on the SBA QDs. The long-term stability of the SBA QDs was greatly enhanced after the gelatin modification. The TEM analysis confirmed that the material retained its rod shape and ordered pores even after gelatin stabilization. The Gel-SBA-QDs exhibited a photoactivation mechanism where the emission intensity of the composite increased upon exposure to UV light. The cytotoxicity assay indicated that the Gel-SBA-QDs showed good viability against the A549 cell line and dose-dependent viability against the Hela cell line. The improved optical properties, stability, and good cell viability characteristics present the as-synthesized Gel-SBA-QDs as an ideal material for theragnostic applications. [ABSTRACT FROM AUTHOR]

Gold nanorods (AuNRs) are powerful photothermal agents (PTAs) in cancer treatment due to their near-infrared laser light absorption ability. However, the cytotoxicity of AuNRs caused by the presence of cationic surfactants often used and their lack of specificity affect their application in photothermal therapy. Thus, we herein developed a bioconjugate obtained from the functionalisation of AuNRs to gelatin (Gel@AuNRs), followed by the conjugation of the as-synthesised material to a breast cancer antibody, trastuzumab (Trast-Gel@AuNRs) to address these issues. The optical and structural characterization of the as-synthesized indicated no significant changes in the optical properties of AuNRs after their functionalisation with gelatin and conjugation with the antibody. The photothermal profiling of the as-synthesised materials showed that AuNRs still have an excellent photothermal conversion efficiency (PCE) after their functionalisation (20%) and their conjugation to an antibody (19%). In addition, the In vitro photothermal depth response showed that Trast-Gel@AuNRs is a promising photothermal agent for HER2-positive breast cancer treatment.Graphical Abstract: Gold nanorods (AuNRs) are powerful photothermal agents (PTAs) in cancer treatment due to their near-infrared laser light absorption ability. However, the cytotoxicity of AuNRs caused by the presence of cationic surfactants often used and their lack of specificity affect their application in photothermal therapy. Thus, we herein developed a bioconjugate obtained from the functionalisation of AuNRs to gelatin (Gel@AuNRs), followed by the conjugation of the as-synthesised material to a breast cancer antibody, trastuzumab (Trast-Gel@AuNRs) to address these issues. The optical and structural characterization of the as-synthesized indicated no significant changes in the optical properties of AuNRs after their functionalisation with gelatin and conjugation with the antibody. The photothermal profiling of the as-synthesised materials showed that AuNRs still have an excellent photothermal conversion efficiency (PCE) after their functionalisation (20%) and their conjugation to an antibody (19%). In addition, the In vitro photothermal depth response showed that Trast-Gel@AuNRs is a promising photothermal agent for HER2-positive breast cancer treatment. [ABSTRACT FROM AUTHOR]

The cadmium complex of N-ethyl-N-phenyl dithiocarbamate, 1, and its 2,2′-bipyridine and 1,10-phenanthroline adducts, 2, and 3, respectively, have been used as single source precursors for the synthesis of CdS nanoparticles. The formation of CdS nanoparticles was achieved by thermal decomposition of the complexes (pyrolysis) and thermolysis in the presence of hexadecylamine – HDA (solvothermal). Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and high resolution transmission electron microscopy (HRTEM) analyses were carried out to study the structural properties of the nanoparticles. Complex 1 afforded rod-shaped nanoparticles while star-shaped nanoparticles were obtained from complexes 2 and 3. The optical property of the CdS nanoparticles was studied by UV–visible and fluorescence spectroscopy. The spectral features for the nanoparticles prepared via the solvothermal route were significantly sharper and blue shifted to a greater extent relative to the corresponding bulk semiconductor, compared to the observed shift in the nanoparticles prepared via pyrolysis. All the as-synthesized material exhibited band edge luminescence. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gold nanorods were synthesized using hydroquinone (HQ) and ascorbic acid (AA). • Ascorbic acid-reduced gelatin-coated gold nanorods are more thermally stable. • A high gelatin volume ratio affects the photothermal response of the gold nanorods. • Ascorbic acid-reduced gelatin-coated gold nanorods gave a better photothermal response. The development of Gold nanorods (AuNRs) as phototherapeutic agents (PTAs) has attracted much interest from researchers in recent decades. The majority of their synthetic methods use Hydroquinone (HQ) and Ascorbic acid (AA) as the reducing agent, and these have been shown to affect the properties of AuNRs. However, no study has been conducted on how these two reducing reagents can affect their application, especially after coating. Therefore, we herein report a seed-mediated synthesis of AuNRs using two reducing agents and coating them with gelatin at different volume ratios (1:5, 1:2, 1:1,2:1, and 5:1). The HQ-reduced AuNRs and AA-reduced AuNRs absorbed at TSPR of 512 nm and 514 nm and LSPR of 914 nm and 847 nm, respectively. The gelatin-coated HQ-reduced and AA-reduced AuNRs did not show significant LSPR wavelength changes for all the volume ratios. However, a slight increase in the TSPR and the absorbance at regions below 550 nm was seen for volume ratios 1:1, 2:1, and 5:1. The thermal stability studies at 70 ℃ for the coated materials revealed that AA-reduced AuNRs were more thermally stable than HQ-reduced AuNRs, with the less optical shift. The coated AA-reduced AuNRs were further tested for photothermal responses. The results show that the high gelatin volume during coating affects the photothermal response of the AuNRs. This study indicates volume ratio of 1:5 and 1:2 has good stability while maintaining the good photothermal profiling needed in PTT applications. Hence Gel@AuNRs synthesised with AA is an excellent PTT agent for phototherapy applications. [ABSTRACT FROM AUTHOR]

Proanthocyanidins (PCs), a component of grape seed extract (GSE), have recently being used for the treatment of wounds. However, poor absorption, poor stability and rapid elimination from the systemic circulation limit its acceptance. In addressing these problems, we herein report the development of PCs based nanoformulations (PCs/SOLU) for the first time based on 1% GSE and assessed its wound healing potential in - vivo on the wistar rats. GSE and PCs/SOLU nanodispersions 1% were prepared by incorporating them into the ointment base via uniform mixing to form ointment which could be easily applied topically to wounds. The antibacterial activity of PCs/SOLU against gram positive and gram-negative bacteria strains proved that the cell membranes became more permeable with disrupted cell structure. While carrageenan and histamine induced rat paw edema analyses show there was no inflammatory signs in animals treated with 1 wt% of PCs/SOLU nanodispersion. Excision wound measuring about 3 cm in depth was created on the wistar rats. The ointment was applied topically on the wounded site and the wound contraction was measured daily. Grape seed extract (GSE) ointment, ointment base and povidone‑iodine (Povi-Iod) ointment of about 1% was used as the control, positive and negative standards. PCs/SOLU nanodispersion heals the wound by mobilising the fibroblasts in the wound site and inhibits the inflammatory response through decreased expression of monocyte. The macroscopical, immunological and histopathological assessments revealed that PCs/SOLU nanodispersion ointment usage improves the cell adhesion and proliferation. Mechanism of wound healing activity of PCs/SOLU Unlabelled Image • Proanthocyanidins based nanoformulations was assessed for wound healing potential. • Antibacterial activity shows rupture of cell and damages the genetic material. • Carrageenan and histamine induced edema analyses showed no inflammatory signs. • Nanodispersion heals the wound by mobilising the fibroblasts in the wound site. • Histopathological assay revealed that nanodispersion improves cell proliferation. [ABSTRACT FROM AUTHOR]

The synthesis and application of porphyrins has seen a huge shift towards research in porphyrin bio-molecular based systems in the past decade. The preferential localization of porphyrins in tumors, as well as their ability to generate reactive singlet oxygen and low dark toxicities has resulted in their use in therapeutic applications such as photodynamic therapy. However, their inherent lack of bio-distribution due to water insolubility has shifted research into porphyrin-nanomaterial conjugated systems to address this challenge. This has broadened their bio-applications, viz. bio-sensors, fluorescence tracking, in vivo magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT imaging to photo-immuno-therapy just to highlight a few. This paper reviews the unique theranostic role of porphyrins in disease diagnosis and therapy. The review highlights porphyrin conjugated systems and their applications. The review ends by bringing current challenges and future perspectives of porphyrin based conjugated systems and their respective applications into light. [ABSTRACT FROM AUTHOR]

Water pollution resulting from toxic organic pollutants has become a global issue and identification of a suitable low cost and non-toxic material possessing catalytic behavior is indispensable in order to circumvent this enigma. For solving this problem, we herein report a quick, cost effective, surfactant-free microwave assisted route for the preparation of hexagonal wurtzite ZnO nanostructures and its photocatalytic performances. Structural, morphological and compositional aspects of the nanostructures were determined by various characterization techniques. The photocatalytic efficacies of the samples monitored for the UV induced degradation of aqueous rhodamine B (RhB) solution indicated that all the nanostructures have high photocatalytic capability with superior performance (C/Co) than many existing reports. The highest photocataytic efficiency was obtained for the sample prepared at 0.5 min with 92% efficiency after three cycles experiment and rate constant of 0.042. The possible mechanism for the growth of ZnO nanostructures and photo degradation is also reported. [ABSTRACT FROM AUTHOR]

We herein report a facile fluorometric method for the detection of Cu2+ ions by using water-soluble glutathione (GSH) capped ternary CuInS 2 /ZnS (CIS/ZnS) quantum dots (QDs). The as-synthesized QDs are ∼3.2 nm in diameter, nearly spherical in shape and fluorescent in the red region. Photostability studies revealed that the as-synthesized CuInS 2 /ZnS QDs maintained 70% of their initial fluorescence after hours of irradiation while the pH analysis showed that the QDs fluorescent emission was stable within the pH 4–11 with maximum stability at pH 6. The fluorometric analysis revealed that the QDs undergoes remarkable photoluminescence quenching in the presence of Cu2+ ions compared to other metal ions such as Hg2+, Co2+, Cd2+, Pb2+, Zn2+, Ni2+, Mg2+, Sn2+, Mn2+, Fe2+, Fe3+ ions. The Fourier transform infra-red (FTIR) spectroscopy, Dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses revealed that the quenching could be attributed to the aggregation of QDs due to the complexation of Cu2+ ions with the GSH capping group of the QDs. The fluorescence quenching of CIS/ZnS QDs exhibited linear response against Cu2+ ions in the concentration range of 75–750 nM with a detection limit of 63 nM. These results reveled that GSH capped CIS/ZnS QD sensor could be a potential fluorescent probe for the detection of Cu2+ ions in aqueous solutions. [ABSTRACT FROM AUTHOR]

The cancer mortality rate has increased, and conventional cancer treatments are known for having many side effects. Therefore, it is imperative to find a new therapeutic agent or modify the existing therapeutic agents for better performance and efficiency. Herein, a synergetic phototherapeutic agent based on a combination of photothermal and photodynamic therapy is proposed. The phototherapeutic agent consists of water-soluble cationic porphyrin (5,10,15,20-tetrakis(N-methylpyridinium-3-yl)porphyrin, TMePyP), and gold nanorods (AuNRs) anchored on graphene-oxide (GO) sheet. The TMePyP was initially synthesized by Adler method, followed by methylation, while GO and AuNRs were synthesized using Hummer's and seed-mediated methods, respectively. The structural and optical properties of TMePyP were confirmed using UV-Vis, zeta analyzer, PL, FTIR and NMR. The formation of both GO and AuNRs was confirmed by UV-Vis-NIR, FTIR, TEM and zeta analyzer. TMePyP and AuNRs were anchored on GO to form GO@AuNRs-TMePyP nanocomposite. The as-synthesized nanocomposite was stable in RPMI and PBS medium, and, on irradiation, produced high heat than the bare AuNRs, with high photothermal efficiency. In addition, the nanocomposite produced higher singlet oxygen than TMePyP with high biocompatibility in the absence of light. These results indicated that the as-synthesized nanocomposite is a promising dual photodynamic and photothermal agent for cancer therapy. [ABSTRACT FROM AUTHOR]

The excellent photothermal properties of gold nanorods (Au-NRs) make them one of the most researched plasmonic photothermal nanomaterials. However, their biological applications have been hampered greatly due to surfactant-induced cytotoxicity. We herein report a simple synthesis of highly biocompatible gelatin stabilized Au-NRs (gelatin@Au-NRs) to address this issue. The optical and structural properties of the as-synthesized gelatin@Au-NRs were investigated by Zetasizer, Ultraviolet-Visible-Near Infrared (UV-Vis-NIR) spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared spectroscopy (FTIR). The as-synthesized gelatin@Au-NRs were highly crystalline and rod-like in shape with an average length and diameter of 66.2 ± 2.3 nm and 10 ± 1.6 nm, respectively. The as-synthesized gelatin@Au-NRs showed high stability in common biological media (phosphate buffer saline and Dulbecco's Modified Eagle's Medium) compared to CTAB capped Au-NRs. Similarly, the gelatin@Au-NRs showed an improved heat production and outstanding cell viability against two different cancer cell lines; KM-Luc/GFP (mouse fibroblast histiocytoma cell line) and FM3A-Luc (breast carcinoma cell line) compared to CTAB capped Au-NRs and PEG@Au-NRs. An in vitro photothermal therapy study against KM-Luc/GFP showed that gelatin@Au-NRs effectively destroys the cancer cells. [ABSTRACT FROM AUTHOR]

Conjugation of photosensitizers (PS) with nanoparticles has been largely used as a strategy to stabilize PS in the biological medium resulting in photosensitizing nanoparticles of enhanced photoactivity. Herein, (Meso-5, 10, 15, 20-tetrakis (3-hydroxyphenyl) phorphyryn (mTHPP) was conjugated with diamond nanoparticles (ND) by covalent bond. Nanoconjugate ND-mTHPP showed suitable stability in aqueous suspension with 58 nm of hydrodynamic diameter and Zeta potential of −23 mV. The antibacterial activity of ND-mTHPP was evaluated against Escherichia coli for different incubation times (0–24 h). The optimal activity was observed after 2 h of incubation and irradiation (660 nm; 51 J/cm2) performed right after the addition of ND-mTHPP (100 μg/mL) to the bacterial suspension. The inhibitory activity was 56% whereas ampicillin at the same conditions provided only 14% of bacterial growth inhibition. SEM images showed agglomerate of ND-mTHPP adsorbed on the bacterial cell wall, suggesting that the antimicrobial activity of ND-mTHPP was afforded by inducing membrane damage. Cytotoxicity against murine embryonic fibroblast cells (MEF) was also evaluated and ND-mTHPP was shown to be noncytotoxic since viability of cells cultured for 24 h in the presence of the nanoconjugate (100 μg/mL) was 78%. Considering the enhanced antibacterial activity and the absence of cytotoxic effect, it is possible to consider the ND-mTHPP nanoconjugate as promising platform for application in antimicrobial photodynamic therapy (aPDT). [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of ZrO 2 NPs by hydrothermal method with monoclinic crystalline structure and average diameter of (50 ± 12 nm). • High stability in suspension: high Zeta potential (+ 48 mV) and low polydispersity index (0.09). • Low cytotoxicity against keratinocytes cells (HaCaT). • Photoprotective effect in HaCaT cells under UV irradiation. The increasing incidence of diseases caused by the harmful effects of UV radiation in skin, predominantly skin cancer, induce the search for more efficient photoprotector agents. Nowadays, titanium dioxide (TiO 2) and zinc oxide (ZnO) are the most widely used photoprotectors and therefore form the main components of commercially available sunscreens. Although the outstanding efficiency in absorbing and scattering UV radiation, mainly as nanoparticles, recent studies have raised concerns regarding the safe use of these nanoparticles, especially due to their high generation of reactive oxygen species (ROS). Thereby, this work focus on the evaluation of the photoprotective activity of zirconia nanoparticles (ZrO 2 NPs) and their cytotoxicity study in the presence and absence of UV irradiation. The ZrO 2 NPs were synthesized by hydrothermal method and their hydrodynamic diameter, Zeta potential and colloidal stability were characterized by dynamic light scattering. The morphology and size were observed by transmission electron microscopy. The synthesis resulted in ZrO 2 NPs with 50 nm of diameter and 56 nm of hydrodynamic diameter. The high colloidal stability was evidenced by the high value of Zeta potential (+48 mV) and low polydispersity index (0.09). The UV–vis spectrum of the ZrO 2 NPs in aqueous suspension showed an intense light scattering below 250 and a wide absorption band at 285 nm. The poor generation of ROS by ZrO 2 NPs was confirmed by the absence of photodegradation of methylene blue after long periods of irradiation. The in vitro assays performed with HaCaT cell line showed that the cell viability did not decrease in the absence of irradiation. However, after 24 h of incubation, the cell viability decreased under UV-irradiation in comparison with irradiated cells that were not incubated with ZrO 2 NPs. Notably, in these assays, the cells were incubated with the ZrO 2 NPs and after 24 h, they were replaced by fresh culture medium before the cell viability assay. Nevertheless, another in vitro assay was performed in order to evaluate the photoprotective activity of ZrO 2 NPs. The cells were irradiated in the presence of ZrO 2 NPs suspension. In this case, cell viability did not decrease even after long period of UV-irradiation and at higher concentration of ZrO 2 NPs. The present results showed that ZrO 2 NPs could be an interesting material to be used for skin photoprotection since they showed low cytotoxicity, absence of ROS generation and protection under UV irradiation. Additionally, the ZrO 2 NPs suspension was transparent as usually required for applications in sunscreens. [ABSTRACT FROM AUTHOR]