Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor cell annihilation upon laser irradiation. The otherwise harmless nature of these NCs in dark conditions was confirmed by in vitro toxicity tests on two different cell lines. The presence of the deep Fe levels constituting the IB is the origin of such enhanced PTE, which can be used to design other high performing NC photothermal agents.Comment: 12 pages, Chemistry of Materials, 31-May-201

Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties and Applications

Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average size of 50 nm exhibit plasmon resonance in the biological transparency window. With dimensions optimized for efficient cellular uptake, the nanoparticles demonstrate a high photothermal conversion efficiency. A self-passivating native oxide at the surface of the nanoparticles provides an additional degree of freedom for surface functionalization.Comment: 17 pages, 4 figures, 1 abstract figur

Functionalized MoS2 nanosheet-capped periodic mesoporous organosilicas as a multifunctional platform for synergistic targeted chemo-photothermal therapy

The combination of different therapies into a single platform has attracted increasing attention as a potential synergistic tumor treatment. Herein, the fabrication of a novel folate targeted system for chemo-photothermal therapy by using thioether-bridged periodic mesoporous organosilica nanoparticles (PMOs) as a drug-loading vehicle is described. The novel targeted molecular bovine serum albumin-folic acid-modified MoS2 sheets (MoS2-PEI-BSA-FA) were successfully synthesized and characterized, and then utilized as a capping agent to block PMOs to control the drug release and to investigate their potential in near-infrared photothermal therapy. The resulting PMOs–DOX@MoS2–PEI-BSA-FA complexes had a uniform diameter (196 nm); high DOX loading capacity (185 mg/g PMOs-SH); excellent photothermal transformation ability; and good biocompatibility in physiological conditions. The PMOs–DOX@MoS2–PEI-BSA-FA exhibited pH-dependence and near infrared (NIR) laser irradiation-triggered DOX release. In vitro experimental results confirmed that the material exhibits excellent photothermal transfer ability, outstanding tumor killing efficiency and specificity to target tumor cells via an FA-receptor-mediated endocytosis process. The in vivo experiments further demonstrated that the platform for synergistic chemo-photothermal therapy could significantly inhibit tumor growth, which is superior to any monotherapy. Meanwhile, cytotoxicity assays and histological assessments show that the engineered PMOs@MoS2–PEI-BSA-FA have good biocompatibility, further inspiring potential biomedical applications. Overall, this work describes an excellent drug delivery system for chemo-photothermal synergistic targeted therapy having good drug release properties, which have great potential in cancer therapy

Phototermal therapy using gold nanoparticles

Cancer is one of the leading causes of mortality worldwide. The fact that most people do not actually die from the cancer itself, but from the side effects of the conventional treatments (e.g. chemotherapy and radiation) has led scientists to find new therapies that can surpass the problem with lack of selectivity and specificity. Nanotechnology is Cancer is one of the leading causes of mortality worldwide. The fact that most people do not actually die from the cancer itself, but from the side effects of the conventional treatments (e.g. chemotherapy and radiation) has led scientists to find new therapies that can surpass the problem with lack of selectivity and specificity. Nanotechnology is still a field in development but it could overcome these problems. It offers great potential in the biomedical field, in imaging, diagnostics, and therapy. Photothermal therapy uses light to induce heat that leads to cell death. Cancer cells have proven to be more vulnerable to increase of heat due to poor blood supply and lack of heat dissipation. Generally this therapy employs near infrared radiation, which allows deep tissue penetration, thus allowing the evasion of absorbance of biomolecules (e.g. hemoglobin). Comparing conventional therapeutic modalities, photothermal therapy shows unique advantages in cancer therapy including high selectivity and specificity, and minimal invasiveness. Gold nanoparticles possess unique optical, electronic and thermal properties for photothermal therapy. Moreover, they are easy to synthetize in aqueous media and can be easily functionalized with a wide range of biomolecules. Modulating the geometric and physical parameters of nanostructures such as shape and size, the plasmon resonance peaks of gold nanoparticles could be tuned to the near-infrared region or the visible region. By using light radiation with a frequency that strongly overlaps the nanoparticle plasmon absorption band, the aim is that the photothermal conversion procedure could be highly efficient. The purpose of this work was to perform a photothermal characterization of gold nanoparticles with different sizes with the perspective of downstream application to photothermal ablation of cancer cells. Synthesis and functionalization of gold nanoparticles with different sizes were performed successfully. Using calorimetry it was concluded that “PEGylated” gold nanoparticles have higher photothermal conversion capacities than the ones with a citrate capping, and that smaller gold nanoparticles are more efficient in converting light to heat than the bigger ones.still a field in development but it could overcome these problems. It offers great potential in the biomedical field, in imaging, diagnostics, and therapy. Photothermal therapy uses light to induce heat that leads to cell death. Cancer cells have proven to be more vulnerable to increase of heat due to poor blood supply and lack of heat dissipation. Generally this therapy employs near infrared radiation, which allows deep tissue penetration, thus allowing the evasion of absorbance of biomolecules (e.g. hemoglobin). Comparing conventional therapeutic modalities, photothermal therapy shows unique advantages in cancer therapy including high selectivity and specificity, and minimal invasiveness. Gold nanoparticles possess unique optical, electronic and thermal properties for photothermal therapy. Moreover, they are easy to synthetize in aqueous media and can be easily functionalized with a wide range of biomolecules. Modulating the geometric and physical parameters of nanostructures such as shape and size, the plasmon resonance peaks of gold nanoparticles could be tuned to the near-infrared region or the visible region. By using light radiation with a frequency that strongly overlaps the nanoparticle plasmon absorption band, the aim is that the photothermal conversion procedure could be highly efficient. The purpose of this work was to perform a photothermal characterization of gold nanoparticles with different sizes with the perspective of downstream application to photothermal ablation of cancer cells. Synthesis and functionalization of gold nanoparticles with different sizes were performed successfully. Using calorimetry it was concluded that “PEGylated” gold nanoparticles have higher photothermal conversion capacities than the ones with a citrate capping, and that smaller gold nanoparticles are more efficient in converting light to heat than the bigger ones

Layer-By-Layer Assembly of Graphene Oxide on Thermosensitive Liposomes for Photo-Chemotherapy

Stimuli responsive polyelectrolyte nanoparticles have been developed for chemo-photothermal destruction of breast cancer cells. This novel system, called layer by layer Lipo-graph (LBL Lipo-graph), is composed of alternate layers of graphene oxide (GO) and graphene oxide conjugated poly (l-lysine) (GO-PLL) deposited on cationic liposomesencapsulating doxorubicin. Various concentrations of GO and GO-PLL were examined and the optimal LBL Lipo-graph was found to have a particle size of 267.9 ± 13 nm, zeta potentialof +43.9 ± 6.9 mV and encapsulation efficiency of 86.4 ± 4.7%. The morphology of LBL Lipo-graph was examined by cryogenic-transmission electron microscopy (Cryo-TEM), atomic force microcopy (AFM) and scanning electron microscopy (SEM). The buildup of LBL Lipo-graph was confirmed via ultraviolet-visible (UV–Vis) spectrophotometry, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Infra-red (IR) response suggests that four layers are sufficient to induce a gel-to-liquid phase transition in response to near infra-red (NIR) laser irradiation. Light-matter interaction of LBL Lipo-graph was studied by calculating the absorption cross section in the frequency domain by utilizing Fourier analysis. Drug release assay indicates that the LBL Lipo-graph releases much faster in an acidic environment than a liposome control. A cytotoxicity assay was conducted to prove the efficacy of LBL Lipo-graph to destroy MD-MB-231 cells in response to NIR laser emission. Also, image stream flow cytometry and two photon microcopy provide supportive data for the potential application of LBL Lipo-graph for photothermal therapy. Study results suggest the novel dual-sensitive nanoparticles allow intracellular doxorubin delivery and respond to either acidic environments or NIR excitation. Statement of Significance Stimuli sensitive hybrid nanoparticles have been synthesized using a layer-by-layer technique and demonstrated for dual chemo-photothermal destruction of breast cancer cells. The hybrid nanoparticles are composed of alternating layers of graphene oxide and graphene oxide conjugated poly-l-lysine coating the surface of a thermosensitive cationic liposome containing doxorubicin as a core. Data suggests that the hybrid nanoparticles may offer many advantages for chemo-photothermal therapy. Advantages include a decrease of the initial burst release which may result in the reduction in systemic toxicity, increase in pH responsivity around the tumor environment and improved NIR light absorption

Photothermal Polymer Nanocomposites of Tungsten Bronze Nanorods with Enhanced Tensile Elongation at Low Filler Contents

We present polymer nanocomposites of tungsten bronze nanorods (TBNRs) and ethylene propylene diene monomers (EPDM). The combination of these components allows the simultaneous enhancement in the mechanical and photothermal properties of the composites at low filler contents. The as-synthesized TBNRs had lengths and diameters of 14.0 +/- 2.4 nm and 2.5 +/- 0.5 nm, respectively, and were capped with oleylamine, which has a chemical structure similar to EPDM, making the TBNRs compatible with the bulk EPDM matrix. The TBNRs absorb a wide range of near-infrared light because of the sub-band transitions induced by alkali metal doping. Thus, the nanocomposites of TBNRs in EPDM showed enhanced photothermal properties owing to the light absorption and subsequent heat emission by the TBNRs. Noticeably, the nanocomposite with only 3 wt% TBNRs presented significantly enhanced tensile strain at break, in comparison with those of pristine EPDM, nanocomposites with 1 and 2 wt % TBNRs, and those with tungsten bronze nanoparticles, because of the alignment of the nanorods during tensile elongation. The photothermal and mechanical properties of these nanocomposites make them promising materials for various applications such as in fibers, foams, clothes with cold weather resistance, patches or mask-like films for efficient transdermal delivery upon heat generation, and photoresponsive surfaces for droplet transport by the thermocapillary effect in microfluidic devices and microengines

Enhanced cancer therapy with cold-controlled drug release and photothermal warming enabled by one nanoplatform

Stimuli-responsive nanoparticles hold great promise for drug delivery to improve the safety and efficacy of cancer therapy. One of the most investigated stimuli-responsive strategies is to induce drug release by heating with laser, ultrasound, or electromagnetic field. More recently, cryosurgery (also called cryotherapy and cryoablation), destruction of diseased tissues by first cooling/freezing and then warming back, has been used to treat various diseases including cancer in the clinic. Here we developed a cold-responsive nanoparticle for controlled drug release as a result of the irreversible disassembly of the nanoparticle when cooled to below ∼10 °C. Furthermore, this nanoparticle can be used to generate localized heating under near infrared (NIR) laser irradiation, which can facilitate the warming process after cooling/freezing during cryosurgery. Indeed, the combination of this cold-responsive nanoparticle with ice cooling and NIR laser irradiation can greatly augment cancer destruction both in vitro and in vivo with no evident systemic toxicity

Local generation of hydrogen for enhanced photothermal therapy.

By delivering the concept of clean hydrogen energy and green catalysis to the biomedical field, engineering of hydrogen-generating nanomaterials for treatment of major diseases holds great promise. Leveraging virtue of versatile abilities of Pd hydride nanomaterials in high/stable hydrogen storage, self-catalytic hydrogenation, near-infrared (NIR) light absorption and photothermal conversion, here we utilize the cubic PdH0.2 nanocrystals for tumour-targeted and photoacoustic imaging (PAI)-guided hydrogenothermal therapy of cancer. The synthesized PdH0.2 nanocrystals have exhibited high intratumoural accumulation capability, clear NIR-controlled hydrogen release behaviours, NIR-enhanced self-catalysis bio-reductivity, high NIR-photothermal effect and PAI performance. With these unique properties of PdH0.2 nanocrystals, synergetic hydrogenothermal therapy with limited systematic toxicity has been achieved by tumour-targeted delivery and PAI-guided NIR-controlled release of bio-reductive hydrogen as well as generation of heat. This hydrogenothermal approach has presented a cancer-selective strategy for synergistic cancer treatment