Near-Infrared Light-Excited Quinolinium-Carbazole Small Molecule as Two-Photon Fluorescence Nucleic Acid Probe

This article reports three new two-photon absorption (TPA) materials that are quinolinium-carbazole derivates. They are 3-(N-methyl-4-ethylquinolinium iodide)-9-ethylcarbazole (M4), 3-(N-methyl-4-ethylquinolinium iodide)-9-ethylcarbazole (H2), and 3-(N-methyl-4-ethylquinolinium iodide)-9-ethylcarbazole (H4). Their TPA cross-sections are 491, 515, and 512 GM, respectively. Under the excitation of near-infrared light, their fluorescence emission is about 650 nm. The compounds can stain nucleic acid DNA with the same level of nuclear localization as Hoechst 33342. Under continuous irradiation with a near-infrared laser, the three new compounds showed less fluorescence decay than DAPI, and the average fluorescence decay rates were 0.016%/s, 0.020%/s, and 0.023%/s. They are expected to become new two-photon fluorescent probes of nucleic acid DNA because of their excellent performance.

Evaluation of thermodynamic bioeffects of long-pulsed 1064 nm laser in the photothermal lipolysis

OBJECTIVES

To evaluate the lipolysis effect of air cooling assisted long-pulsed 1064 laser for improving local adiposity.

MATERIALS AND METHODS

The second-level (pulse duration of 0.3-60 s) long-pulsed Nd:YAG 1064 nm laser (LP1064 nm) with or without forced-air cooling was used to irradiate ex-vivo subcutaneous adipose tissue (SAT) of pig or human and in-vivo inguinal fat tissue of Sprague Dawley rats. The temperature of skin surface as well as 5 mm deep SAT was monitored by a plug-in probe thermal couple, and the former was confined to 39°C or 42°C during the treatment. Histological analysis of SAT response was evaluated by SAT sections stained with hematoxylin-eosin and oil red O. Ultra-microstructure changes were examined by transmission electron microscopy. A pilot study on human subject utilizing LP1064 nm laser with air cooling was conducted. The changes in gross abdomen circumference and ultrasonic imaging were studied.

RESULTS

Histological examination showed that LP1064 nm laser treatment induced adipocyte injury and hyperthermic lipolysis both in- and ex-vivo. It was also confirmed by clinical practice on patients. By real-time temperature monitoring, we found that in comparison with LP1064 nm laser alone, additional air cooling could increase the temperature difference between epidermis and SAT, promoting heat accumulation deep in fat tissue, as well as providing better protection for epidermis.

CONCLUSION

LP1064 nm laser provided reliable adipose tissue thermolysis when the temperature of skin surface was sustained at 39°C or 42°C for 10 min. Application of air-cooling during the laser treatment achieved better effect and safety of photothermal lipolysis. LP1064 nm laser, as a noninvasive device, has comparable thermal lipolysis effect as other common heat-generating devices.

Carbon Dots with Blue-to-Near-Infrared Lasing for Colorful Speckle-Free Laser Imaging and Dynamical Holographic Display

As a new solution-processable laser material, carbon dots (CDs) offer advantages of non-toxicity, low cost, and high stability, which are conducive to the sustainable development of miniaturized lasers. We prepared full-color CDs (FC-CDs) with bright-blue, green, yellow, red, deep-red, and near-infrared (NIR) fluorescence. Their photoluminescence emission ranged from 431 to 714 nm. The FC-CDs showed narrow full widths at half maximum in the range of 44-76 nm, with concurrent high radiative transition rates (K_R ) of 0.54-1.74 × 10⁸ s^-1 ; their performance is comparable to that of organic laser dyes, indicating their good gain potential for lasers. Laser pumping of the FC-CDs gave laser outputs at 467.3, 533.5, 577.4, 616.3, 653.5, and 705.1 nm, spanning from blue to NIR region, and covering 140% of the NTSC color gamut. The FC-CDs showed high Q-factors (2000-5500), appreciable gain coefficients (9-21.5 cm^-1 ), and better stability (∼100%@4-7 h) than commercial laser dyes. These excellent properties make them suitable for high-quality, colorful, speckle-free laser imaging and dynamic holographic display. Our findings will be helpful in promoting the practical applications and development of solution-processable CD-based lasers. This article is protected by copyright. All rights reserved.

Photothermal-Controlled Release of IL-4 in IL-4/PDA-Immobilized Black Titanium Dioxide (TiO2) Nanotubes Surface to Enhance Osseointegration: An In Vivo Study

Host immune response has gradually been accepted as a critical factor in achieving successful implant osseointegration. The aim of this study is to create a favorable immune microenvironment by the dominant release of IL-4 during the initial few days after implant insertion to mitigate early inflammatory reactions and facilitate osseointegration. Herein, the B-TNT/PDA/IL-4 substrate was established by immobilizing an interleukin-4 (IL-4)/polydopamine (PDA) coating on a black TiO₂ nanotube (B-TNT) surface, achieving on-demand IL-4 release under near infrared (NIR) irradiation. Gene Ontology (GO) enrichment analyses based on high-throughput DNA microarray data revealed that IL-4 addition inhibited osteoclast differentiation and function. Animal experiment results suggested that the B-TNT/PDA/IL-4+Laser substrate induced the least inflammatory, tartrate-resistant acid phosphatase, inducible nitric oxide synthase and the most CD163 positive cells, compared to the Ti group at 7 days post-implantation. In addition, 28 days post-implantation, micro-computed tomography results showed the highest bone volume/total volume, trabecular thickness, trabecular number and the lowest trabecular separation, while Hematoxylin-eosin and Masson-trichrome staining revealed the largest amount of new bone formation for the B-TNT/PDA/IL-4+Laser group. This study revealed the osteoimmunoregulatory function of the novel B-TNT/PDA/IL-4 surface by photothermal release of IL-4 at an early period post-implantation, thus paving a new way for dental implant surface modification.

The synergistic effect of chemo-photothermal therapies in SN-38-loaded gold-nanoshell-based colorectal cancer treatment

Aim: 7-Ethyl-10-hydroxycamptothecin (SN-38)-loaded gold nanoshells nanoparticles (HSP@Au NPs) were developed for combined chemo-photothermal therapy to treat colorectal cancer. Materials & methods: SN-38-loaded nanoparticles (HSP NPs) were prepared by the lyophilization-hydration method, and then developed into gold nanoshells. The nanoparticles were characterized and assessed for photothermal properties, cytotoxicity and hemocompatibility in vitro. In vivo anticancer activity was tested in a tumor mouse model. Results: The HSP@Au NPs (diameter 186.9 nm, zeta potential 33.4 mV) led to significant cytotoxicity in cancer cells exposed to a near-infrared laser. Moreover, the HSP@Au NP-mediated chemo-photothermal therapy displayed significant tumor growth suppression and disappearance (25% of tumor clearance rate) without adverse side effects in vivo. Conclusion: HSP@Au NPs may be promising in the treatment of colorectal cancer in the future.

Brief exposure of skin to near-infrared laser augments early vaccine responses

Rapid establishment of herd immunity with vaccination is effective to combat emerging infectious diseases. Although the incorporation of adjuvant and intradermal (ID) injection could augment early responses to the vaccine, the current chemical or biological adjuvants are inappropriate for this purpose with their side effects and high reactogenicity in the skin. Recently, a near-infrared (NIR) laser has been shown to augment the immune response to ID vaccination and could be alternatively used for mass vaccination programs. Here, we determined the effect of NIR laser as well as licensed chemical adjuvants on the immunogenicity 1, 2, and 4 weeks after ID influenza vaccination in mice. The NIR laser adjuvant augmented early antibody responses, while the widely used alum adjuvant induced significantly delayed responses. In addition, the oil-in-water and alum adjuvants, but not the NIR laser, elicited escalated T_H2 responses with allergenic immunoglobulin E (IgE) responses. The effect of the NIR laser was significantly suppressed in the basic leucine zipper transcription factor ATF-like 3 (Batf3) knockout mice, suggesting a critical role of the cluster of differentiation 103⁺ (CD103)⁺ dendritic cells. The current preliminary study suggests that NIR laser adjuvant is an alternative strategy to chemical and biological agents to timely combat emerging infectious diseases. Moreover, its immunomodulatory property could be used to enhance the efficacy of immunotherapy for allergy and cancer.

Iron Hydroxide/Oxide-Reduced Graphene Oxide Nanocomposite for Dual-Modality Photodynamic and Photothermal Therapy In Vitro and In Vivo

Minimal invasive phototherapy utilising near-infrared (NIR) laser to generate local reactive oxygen species (ROS) and heat has few associated side effects and is a precise treatment in cancer therapy. However, high-efficiency and safe phototherapeutic tumour agents still need developing. The application of iron hydroxide/oxide immobilised on reduced graphene oxide (FeOxH–rGO) nanocomposites as a therapeutic agent in integration photodynamic cancer therapy (PDT) and photothermal cancer therapy (PTT) was discussed. Under 808 nm NIR irradiation, FeOxH–rGO offers a high ROS generation and light-to-heat conversion efficiency because of its strong NIR absorption. These phototherapeutic effects lead to irreversible damage in FeOxH–rGO-treated T47D cells. Using a tumour-bearing mouse model, NIR ablated the breast tumour effectively in the presence of FeOxH–rGO. The tumour treatment response was evaluated to be 100%. We integrated PDT and PTT into a single nanodevice to facilitate effective cancer therapy. Our FeOxH–rGO, which integrates the merits of FeOxH and rGO, displays an outstanding tumoricidal capacity, suggesting the utilization of this nanocomposites in future medical applications.

A novel Vancomycin-Functionalized-Magnetic Graphene Composite for Use as a Near-Infrared-Induced Synergistic Chemo-Photothermal Antibacterial

Antibiotic-resistant bacterial strains are a major cause of disease. They continue to remain a challenge in the clinic particularly in the vision system. For example, infectious endophthalmitis is a major blind-causing disease caused by bacteria. A highly efficient synergistic antibacterial treatment that uses a photothermal antibacterial therapeutic with a chemo-antibacterial therapeutic in a multifunctional nanocomposite is reported. It is prepared by immobilizing vancomycin onto the surface of a magnetic chitosan-graphene (VCM-MCG) composite. An antibacterial effect is achieved when VCM-MCG is applied. This effect is enhanced when the nanocomposites are irradiated with a near-infrared laser. Growth of gram-positive methicillin-resistant Staphylococcus aureus and gram-negative Escherichia coli bacteria are suppressed efficiently. Such a composite can help manage the control of pathogenic bacteria growth in the clinic.

A Near-Infrared Laser-Triggered Size-Shrinkable Nanosystem with In Situ Drug Release for Deep Tumor Penetration

The development of smart size-tunable drug delivery nanoplatform enables the solving of the paradox of inconsistent size-dependence of high tumor accumulation and deep penetration during its delivery process, thus achieving superior cancer treatment efficacy. Herein, we report a size-shrinkable nanomicelle complex system with an initial size of 101 nm enabling effective retention around the tumor periphery and could destruct to ultrasmall nanomicelles triggered by a near-infrared (NIR) laser to realize the deep tumor penetration. The nanomicelle system is consisted of an upper critical solution temperature (UCST)-type block copolymer poly(acrylamide-acrylonitrile)-polyethylene glycol-lipoic acid (p(AAm-co-AN)-g-PEG-LA) encapsulating gold nanorods. Upon the irradiation of the NIR laser at the tumor site, gold nanorods could convert the light energy to heat energy, realizing the photothermal ablation of superficial tumor tissue. Concurrently, the large micelles split into a cascade of ultrasmall micelles (∼7 nm), which could easily penetrate into the deep site of the tumor and achieve the in situ "on-demand" release of the loaded drug to exert superior combined photothermal-chemotherapy of cancer. By the precise manipulation of laser, the micelle complex system realized the hierarchical killing from the superficial-to-deep tumor and achieved almost complete tumor growth inhibition on the established xenograft liver tumor mice model.

Pnictogen Semimetal (Sb, Bi)-Based Nanomaterials for Cancer Imaging and Therapy: A Materials Perspective

Innovative multifunctional nanomaterials have attracted tremendous interest in current research by facilitating simultaneous cancer imaging and therapy. Among them, antimony (Sb)- and bismuth (Bi)-based nanoparticles are important species with multifunction to boost cancer theranostic efficacy. Despite the rapid development, the extensive previous work treated Sb- and Bi-based nanoparticles as mutually independent species, and therefore a thorough understanding of their relationship in cancer theranostics was lacking. We propose here that the identical chemical nature of Sb and Bi, being semimetals, provides their derived nanoparticles with inherent multifunction for near-infrared laser-driven and/or X-ray-based cancer imaging and therapy as well as some other imparted functions. An overview of recent progress on Sb- and Bi-based nanoparticles for cancer theranostics is provided to highlight the relationship between chemical nature and multifunction. The understanding of Sb- and Bi-based nanoparticles in this way might shed light on the further design of smart multifunctional nanoparticles for cancer theranostics.

ICG/5-Fu coencapsulated temperature stimulus response nanogel drug delivery platform for chemo-photothermal/photodynamic synergetic therapy

The multiple diagnosis and treatment mechanisms of chemotherapy combined with photothermal/photodynamic therapy have very large application prospects in the field of cancer treatment. Therefore, in order to achieve effective and safe antitumour treatment, it is necessary to design an intelligent responsive polymer nanoplatform as a drug delivery system. Herein, the thermosensitive poly-N-isopropylacrylamide (PNIPAM) nanogel particles were prepared by soap-free emulsion polymerization and loaded with a large amount of photosensitizer indocyanine green (ICG) and anticarcinogen 5-fluorouracil (5-Fu), which effectively to realize the cooperative chemotherapy and photothermal/photodynamic therapy for tumours. The 5-Fu@ICG-PNIPAM nanogels significantly improved the bioavailability of the drug and achieved controlled release. In addition, under near-infrared laser (NIR) irradiation at 808 nm, 5-Fu@ICG-PNIPAM nanogels generated lots of heat and reactive oxygen, which significantly enhanced cellular uptake and in vitro antitumour treatment effects. The results showed that 5-Fu@ICG-PNIPAM nanogels were effectively endocytosed by HeLa cells, which also enhanced the drug's entrance into the nucleus. Moreover, compared with alone chemotherapy or photothermal/photodynamic therapy, 5-Fu@ICG-PNIPAM nanogels significantly increased cytotoxicity under NIR irradiation, suggesting that chemotherapy and photothermal/photodynamic synergistic therapy had excellent antitumour properties. Therefore, this temperature-responsive nanogel platform probably has great application prospects in clinical antitumour treatment.

Photoresponsive miR-34a/Nanoshell Conjugates Enable Light-Triggered Gene Regulation to Impair the Function of Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is an aggressive disease that requires new interventions. A promising approach to improve patient prognosis is to introduce tumor suppressive miR-34a into TNBC cells. Unfortunately, naked miR-34a is not effective therapeutically because it is degraded by nucleases and cannot passively enter cells. Nanocarriers designed to increase miR-34a stability and cellular entry have lacked specificity and potency. To overcome these limitations, we conjugated miR-34a to photoresponsive gold nanoshells (NS), which can release tethered miR-34a upon excitation with continuous wave (CW) or nanosecond (ns) pulsed near-infrared light to facilitate on-demand gene regulation. We demonstrate that miR-34a/NS can regulate downstream miR-34a targets following irradiation to reduce TNBC cell viability, proliferation, and migration. Further, we show ns pulsed light releases miRNA more effectively than CW light, and that released miR-34a is as potent as transfected miR-34a. These findings signify miR-34a/NS as promising tools for precisely controlled gene regulation of TNBC.

Influence of natural convection on gold nanorods-assisted photothermal treatment of bladder cancer in mice

Background: The thermally-induced urine flow can generate cooling that may alter the treatment outcome during hyperthermic treatments of bladder cancer. This paper investigates the effects of natural convection inside the bladder and at skin surface during gold nanorods (GNR) - assisted photothermal therapy (PTT) of bladder cancer in mice. Methods: 3D models of mouse bladder at orientations corresponding to the mouse positioned on its back, its side and its abdomen were examined. Numerical simulations were carried out for GNR volume fractions of 0.001, 0.005 and 0.01% and laser power of 0.2 and 0.3 W. Results: The obtained results showed that cooling due to natural convection inside the bladder and above the skin depends on the mouse orientation. For a mouse positioned on its back, on its side or on its abdomen, the maximum temperature achieved inside the tumour at 0.001% GNR volume fraction and 0.2 W laser power was 55.2°C, 50.0°C and 52.2°C, respectively compared to 56.8°C when natural convection was not considered. The average thermal gradients when natural convection was considered were also lower, suggesting a more homogenous temperature distribution. Conclusions: Natural convection inside the bladder can be beneficial but also detrimental to GNR-assisted PTT depending on the level of heating. At low levels of heating due to low GNR volume fraction and/or laser power, flow inside the bladder may dissipate heat from the targeted tissue; making the treatment ineffective. At high levels of heating due to high GNR volume fraction and/or laser power, cooling may prevent excessive thermal damage to surrounding tissues.

High-throughput single-cell live imaging of photobiomodulation with multispectral near-infrared lasers in cultured T cells

SIGNIFICANCE

Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology.

AIM

Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light.

APPROACH

In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature.

RESULTS

A specific combination of wavelengths at low irradiances (250 to 400  mW  /  cm2 for 1064 nm and 55 to 65  mW  /  cm2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes.

CONCLUSIONS

This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.

Development of a Near-infrared Laser-induced Surface Deformation Microscope and Its Application to the Dynamic Viscoelastic Measurements of Single Living Plant Cell Surfaces

A near-infrared laser-induced surface deformation (NIR-LISD) microscope is developed and is applied to the dynamic viscoelastic measurements of the surface of a living plant cell. In the microscope, the deformation of the surface is induced by an NIR laser beam, and then the change in intensity of the probe beam reflected from the surface reflects its viscoelasticity. The application of the NIR laser beam has a great advantage for the prevention of damage to the plant cell compared to the irradiation of a visible laser beam in LISD measurements. The NIR-LISD microscope allows for discriminating the differences in power spectra between the subapical and lateral regions of single rhizoids. It is a useful method for the dynamic viscoelastic measurements of cells, such as plant cells, that are damaged due to the strong absorption of ultraviolet or visible light.

Treatment of acne scarring with a novel dual-wavelength laser

BACKGROUND

Facial acne scarring is a prevalent disease with both physical and psychosocial sequelae.

AIMS

This study aims to evaluate an innovative solid state dual wavelength 1,319 and 589 nm laser, which does not require consumable dye, for the treatment of acne scars.

PATIENTS/METHODS

A total of 12 patients (11 female, 1 man - Fitzpatrick skin phototypes II & III) with acne scar for more than one year, were treated with 1319 nm and subsequently by 589 nm, all having four-sessions, one every other week. A full face was covered in approximately 30 minutes. Acne scars were scored by one physician evaluator using the ECCA grading scale before, 2 weeks after each treatment and 1 month and 6 months after the 4th treatment. Safety was measured by recording subject discomfort scores and adverse effects.

RESULTS

12 subjects were enrolled into the study, 10 completed all 4 treatments and 2 were lost to follow up. Fluence used was 28 J/cm² ± 2.4 J/cm² at 1,319 nm and 16 ± 2.9 J/cm² at 589 nm. At baseline, mean ECCA score was 98 ± 23. This score was reduced to 88 ± 30 (p<0.02), after one session, to 68 ± 21 (p<0.01) after 2 sessions, to 58 ± 17 (p<0.01) after 3 sessions to reach 58 ± 15 (p<0.01) 1 month after the 4th and finally 66 ± 11 (p<0.01) at 6 month follow up. This observation corresponds respectively to 14%, 33%, 42%, 40% and 30% reduction of the ECCA score. Only one patient (ECCA score: 120) did not improve after 3 sessions. Slight to moderate erythema was sometimes observed without dryness or bruising. No or minimal burning or stinging was reported. No crust was observed.

CONCLUSION

Improvement in scarring was noted in almost all patients with minimal discomfort and minimal downtime. Combining both minimal side effects with effective acne scar reduction, this laser appears to be highly effective. Long-term evaluation remains necessary to confirm the efficacy of this new laser.

Photothermal Effects of Reduced Graphene Oxide on Pancreatic Cancer

Pancreatic cancer is a malignant tumor model with high mortality. Many patients are ineligible for surgical resection once diagnosed; therefore, it is important to explore more safe and effective treatment options. This study was designed to determine the therapeutic effect of reduced graphene oxide combined with the near-infrared laser in animal pancreatic cancer. The results showed that reduced graphene oxide has strong light absorption ability between 600 and 1100 nm detected by spectrophotometer. Experimental results of different concentrations of reduced graphene oxide solution under 980-nm laser irradiation at different powers showed that the enhancement of the photothermal conversion effect of reduced graphene oxide depends on reduced graphene oxide concentration and light dose. In vivo experiments showed that higher laser dose (0.75 W/cm²) combined with higher reduced graphene oxide concentration (2 mg/kg) can achieve higher treatment temperature and slower tumor growth. These results suggest that reduced graphene oxide combined with the 980-nm laser in the treatment of mouse pancreatic cancer can get an ideal thermal killing effect, with the clinical potential of pancreatic cancer treatment.

Effect of 810 nm Near-Infrared Laser on Revascularization of Ischemic Flaps in Rats

OBJECTIVE

To investigate the effect of 810 nm near-infrared (NIR) laser on the revascularization of ischemic flaps.

BACKGROUND

It has long been proved that photobiomodulation therapy (PBMT) improves the blood supply of flaps. NIR laser improves the treatment of hypodermis-located lesions and of flap survival, but basic research on the use of 810 nm NIR laser for ischemic flap revascularization is still lacking.

MATERIALS AND METHODS

We prepared two symmetrical long random-pattern flaps on the backs of 60 rats. Each flap was 6 cm long, 1 cm wide, and 1 cm to the middle line. The flaps were divided into an irradiated flap group and an internal control group. The irradiated flaps underwent postoperative 810 nm laser therapy with the energy density of 11.30 J/cm² daily. The control flaps were covered by stainless steel to avoid laser irradiation. We observed the viability of the flaps. The flaps underwent Hematoxylin and Eosin (H&E) staining for the observation of histomorphology, immunohistochemical staining of factor VIII for the capillary count, α-smooth muscle actin for the small arterial count, and vascular endothelial growth factor for the integrated optical density (OD) of the positive stained color.

RESULTS

The irradiated flaps showed significantly better flap survival than the control flaps. H&E staining showed that the irradiated flaps had clear tissue structure and little inflammatory cell infiltration. The control flaps demonstrated comparatively worse results. Vascular endothelial growth factor staining showed that the difference in integrated OD between the irradiated flaps and the control flaps was not statistically significant. α-smooth muscle actin and factor VIII staining showed significantly greater numbers of arterioles and capillaries in the irradiated flaps than the control flaps after 4 days of irradiation.

CONCLUSIONS

PBMT with 810 nm NIR laser could enhance ischemic flap revascularization and increase flap viability.

Photodynamic therapy at ultra-low NIR laser power and X-Ray imaging using Cu3BiS3 nanocrystals

Materials with efficient potential in imaging as well as therapy are gaining particular attention in current medical research. Photodynamic therapy (PDT) has been recently recognized as a promising treatment option for solid tumors. Still, most of the nanomaterial-based PDT modules either employ an additional photosensitizer or require high power laser sources. Also, they suffer from a lack of responsiveness in the near-infrared (NIR) region. Nanomaterials that could realize PDT independently (without any photosensitizer), at safe laser dose and in the deep tissue penetrative NIR region would definitely be better solid tumor treatment options. Methods: Herein, Cu- and Bi-based bimetal chalcogenide (Cu3BiS3), with absorption in the NIR region was developed. High-performance PDT of cancer and high-contrast x-ray imaging of tumor were performed in vivo. Biocompatibility of the NCs was also assessed in vivo. Results: The highlight of the results was the realization of ultra-low dose NIR laser-mediated PDT, which has not been achieved before, leading to complete tumor regression. This could be a breakthrough in providing a pain- and scar-less treatment option, especially for solid tumors and malignant/benign subcutaneous masses. Though the NCs are active in the photo-thermal therapy (PTT) regime as well, focus is given to the exciting aspect of extremely low power-induced PDT observed here. Conclusion: Their extended in vivo biodistribution with commendable hemo- and histo-compatibilities, along with imaging and multi-therapeutic capabilities, project these Cu3BiS3 NCs as promising, prospective theranostic candidates.

Suppressing Nonradiative Processes of Organic Dye with Metal-Organic Framework Encapsulation toward Near-Infrared Solid-State Microlasers

Organic materials are an important class of gain media for fabricating miniaturized lasers because they combine fabrication simplicity with wide spectral coverage and tunability. However, progress toward near-infrared (NIR) organic solid-state lasers has been limited because of serious nonradiative processes originating from the severe intermolecular interaction in the condensed state. Here, we develop a strategy to realize room-temperature NIR microscale lasers through encapsulating organic dyes into the cavities of metal-organic frameworks (MOFs). The spatial confinement of the dye molecules within the MOF pores contributes to suppressing the multiple nonradiative processes (i.e., aggregation-caused quenching and exciton-exciton annihilation). This results in a much higher radiative efficiency and thus much easier population inversion and low-threshold NIR lasing. Furthermore, the lasing wavelength can be further expanded based on the tailorable energy levels of the dye molecules. The results will provide useful enlightenment for the development of miniaturized NIR laser sources for new photonic applications.

Photothermal exposure of polydopamine-coated branched Au-Ag nanoparticles induces cell cycle arrest, apoptosis, and autophagy in human bladder cancer cells

Purpose

Polydopamine-coated branched Au–Ag nanoparticles (Au–Ag@PDA NPs) exhibit good structural stability, biocompatibility, and photothermal performance, along with potential anticancer efficacy. Here, we investigated the cytotoxicity of Au–Ag@PDA NPs against human bladder cancer cells (T24 cells) in vitro and in vivo, as well as the underlying molecular mechanisms of photothermal therapy-induced T24 cell death.

Materials and methods

T24 cells were treated with different doses of Au–Ag@PDA NPs followed by 808 nm laser irradiation, and the effects on cell proliferation, cell cycle, apoptosis, and autophagy were analyzed. To confirm the mechanisms of inhibition, real-time PCR and Western blot analysis were used to evaluate markers of cell cycle, apoptosis, autophagy, and the AKT/ERK signaling pathway. Moreover, we evaluated the effects of the treatment on mitochondrial membrane potential and ROS generation to confirm the underlying mechanisms of inhibition. Finally, we tested the T24 tumor inhibitory effects of Au–Ag@PDA NPs plus laser irradiation in vivo using a xenograft mouse model.

Results

Au–Ag@PDA NPs, with appropriate laser irradiation, dramatically inhibited the proliferation of T24 cells, altered the cell cycle distribution by increasing the proportion of cells in the S phase, induced cell apoptosis by activating the mitochondria-mediated intrinsic pathway, and triggered a robust autophagy response in T24 cells. Moreover, Au–Ag@PDA NPs decreased the expression of phosphorylated AKT and ERK and promoted the production of ROS that function upstream of apoptosis and autophagy. In addition, Au–Ag@PDA NP-mediated photothermolysis also significantly suppressed tumor growth in vivo.

Conclusion

This preclinical study can provide a mechanistic basis for Au–Ag@PDA NP-mediated photothermal therapy toward promotion of this method in the clinical treatment of bladder cancer.

Near-infrared laser-mediated drug release and antibacterial activity of gold nanorod-sputtered titania nanotubes

The infection control of implants is one of the hot issues in the field of medicine and dentistry. In this study, we prepared gold nanorod–sputtered titania nanotubes on titanium surface, which is the main component of implant material, and aimed to estimate the remote-controlled tetracycline release and resulting antibacterial effects of gold nanorod–sputtered titania nanotubes using near-infrared laser irradiation. Gold nanorods prepared by ion plasma sputtering (aspect ratio = 1:3) showed optical properties like those of chemically synthesized gold nanorods, exhibiting photothermal effects in the near-infrared region, as demonstrated using field-emission scanning electron microscopy, transmission electron microscopy, and diffuse ultraviolet–visible–near-infrared spectrophotometry. In addition, a 2 wt% tetracycline/polycaprolactone mixture was found to be the most suitable experimental group to demonstrate the biological compatibilities and antibacterial activities. The results of antibacterial agar diffusion tests and near-infrared-mediated tetracycline release tests in vivo confirmed that remote-controlled tetracycline elution using near-infrared laser irradiation was highly effective. Therefore, gold nanorod–sputtered titania nanotubes would be expected to enable the continued use of the photothermal therapy of gold nanorods and extend the limited use of titania showing photocatalytic activity only within the ultraviolet-to-near-infrared region.

Controlling the near-infrared transparency of costal cartilage by impregnation with clearing agents and magnetite nanoparticles

Penetration depth of near-infrared laser radiation to costal cartilage is controlled by the tissue absorption and scattering, and it is the critical parameter to provide the relaxation of mechanical stress throughout the whole thickness of cartilage implant. To enhance the penetration for the laser radiation on 1.56 μm, the optical clearing solutions of glycerol and fructose of various concentrations are tested. The effective and reversible tissue clearance was achieved. However, the increasing absorption of radiation should be concerned: 5°C-8°C increase of tissue temperature was detected. Laser parameters used for stress relaxation in cartilage should be optimized when applying optical clearing agents. To concentrate the absorption in the superficial tissue layers, magnetite nanoparticle (NP) dispersions with the mean size 95 ± 5 nm and concentration 3.9 ± 1.1 × 10¹¹ particles/mL are applied. The significant increase in the tissue heating rate was observed along with the decrease in its transparency. Using NPs the respective laser power can be decreased, allowing us to obtain the working temperature locally with reduced thermal effect on the surrounding tissue.

2D Material-Based Nanofibrous Membrane for Photothermal Cancer Therapy

One of the clinical challenges facing photothermal cancer therapy is health risks imposed by the photothermal nanoagents in vivo. Herein, a photothermal therapy (PTT) platform composed of a 2D material-based nanofibrous membrane as the agent to deliver thermal energy to tumors under near-infrared (NIR) light irradiation is described. The photothermal membrane, which is fabricated by an electrospinning poly(l-lactic acid) (PLLA) nanofibrous membrane loaded with bismuth selenide (Bi₂Se₃) nanoplates, exhibits very high photothermal conversion efficiency and long-term stability. Cell experiments and hematological analyses demonstrate that the Bi₂Se₃/PLLA membranes have excellent biocompatibility and low toxicity. PTT experiments performed in vivo with the Bi₂Se₃/PLLA membrane covering the tumor and NIR irradiation produce local hyperthermia to ablate the tumor with high efficiency. Different from the traditional systematical and local injection techniques, this membrane-based PTT platform is promising in photothermal cancer therapy, especially suitable for the treatment of multiple solid tumors or skin cancers, and long-term prevention of cancer recurrence after surgery or PTT, while eliminating the health hazards of nanoagents.

Enhanced Tissue Ablation Efficiency with a Mid-Infrared Nonlinear Frequency Conversion Laser System and Tissue Interaction Monitoring Using Optical Coherence Tomography

We report development of optical parametric oscillator (OPO)-based mid-infrared laser system that utilizes a periodically poled nonlinear crystal pumped by a near-infrared (NIR) laser. We obtained a mid-infrared average output of 8 W at an injection current of 20 A from a quasi-phase-matched OPO using an external cavity configuration. Laser tissue ablation efficiency is substantially affected by several parameters, including an optical fluence rate, wavelength of the laser source, and the optical properties of target tissue. Dimensions of wavelength and radiant exposure dependent tissue ablation are quantified using Fourier domain optical coherence tomography and the ablation efficiency was compared to a non-converted NIR laser system.

A Multimodal System with Synergistic Effects of Magneto-Mechanical, Photothermal, Photodynamic and Chemo Therapies of Cancer in Graphene-Quantum Dot-Coated Hollow Magnetic Nanospheres

In this study, a multimodal therapeutic system was shown to be much more lethal in cancer cell killing compared to a single means of nano therapy, be it photothermal or photodynamic. Hollow magnetic nanospheres (HMNSs) were designed and synthesized for the synergistic effects of both magneto-mechanical and photothermal cancer therapy. By these combined stimuli, the cancer cells were structurally and physically destroyed with the morphological characteristics distinctively different from those by other therapeutics. HMNSs were also coated with the silica shells and conjugated with carboxylated graphene quantum dots (GQDs) as a core-shell composite: HMNS/SiO2/GQDs. The composite was further loaded with an anticancer drug doxorubicin (DOX) and stabilized with liposomes. The multimodal system was able to kill cancer cells with four different therapeutic mechanisms in a synergetic and multilateral fashion, namely, the magnetic field-mediated mechanical stimulation, photothermal damage, photodynamic toxicity, and chemotherapy. The unique nanocomposites with combined mechanical, chemo, and physical effects will provide an alternative strategy for highly improved cancer therapy efficiency.

Thermal impact of near-infrared laser in advanced noninvasive optical brain imaging

The propagation of laser light in human tissues is an important issue in functional optical imaging. We modeled the thermal effect of different laser powers with various spot sizes and different head tissue characteristics on neonatal and adult quasirealistic head models. The photothermal effect of near-infrared laser (800 nm) was investigated by numerical simulation using finite-element analysis. Our results demonstrate that the maximum temperature increase on the brain for laser irradiance between 0.127 (1 mW) and [Formula: see text] (100 mW) at a 1 mm spot size, ranged from 0.0025°C to 0.26°C and from 0.03°C to 2.85°C at depths of 15.9 and 4.9 mm in the adult and neonatal brain, respectively. Due to the shorter distance of the head layers from the neonatal head surface, the maximum temperature increase was higher in the neonatal brain than in the adult brain. Our results also show that, at constant power, spot size changes had a lesser heating effect on deeper tissues. While the constraints for safe laser irradiation to the brain are dictated by skin safety, these results can be useful to optimize laser parameters for a variety of laser applications in the brain. Moreover, combining simulation and adequate in vitro experiments could help to develop more effective optical imaging to avoid possible tissue damage.

Light therapy modulates serotonin levels and blood flow in women with headache. A preliminary study

In this study, we looked at the possible effects of low-level laser therapy (LLLT) on blood flow velocity, and serotonin (5-HT) and cholinesterase levels in patients with chronic headache associated with temporomandibular disorders (TMD). LLLT has been clinically applied over the past years with positive results in analgesia and without the report of any side effects. The understanding of biological mechanisms of action may improve clinical results and facilitate its indication. Ten patients presenting headache associated with TMD completed the study. An 830-nm infrared diode laser with power of 100 mW, exposure time of 34 s, and energy of 3.4 J was applied on the tender points of masseter and temporal muscle. Blood flow velocity was determined via ultrasound Doppler velocimetry before and after laser irradiation. The whole blood 5-HT and cholinesterase levels were evaluated three days before, immediately, and three days after laser irradiation. Pain score after treatment decreased to a score of 5.8 corresponding to 64% of pain reduction (P < 0.05). LLLT promoted a decrease in the blood flow velocity (P < 0.05). In addition, the 5-HT levels were significantly increased three days after LLLT (P < 0.05). The cholinesterase levels remained unchanged at the analyzed time points (P > 0.05). Our findings indicated that LLLT regulates blood flow in the temporal artery after irradiation and might control 5-HT levels in patients suffering with tension-type headache associated to TMD contributing to pain relief.

Targeted intracellular delivery of proteins with spatial and temporal control

While a host of methods exist to deliver genetic materials or small molecules to cells, very few are available for protein delivery to the cytosol. We describe a modular, light-activated nanocarrier that transports proteins into cells by receptor-mediated endocytosis and delivers the cargo to the cytosol by light triggered endosomal escape. The platform is based on hollow gold nanoshells (HGN) with polyhistidine tagged proteins attached through an avidity-enhanced, nickel chelation linking layer; here, we used green fluorescent protein (GFP) as a model deliverable cargo. Endosomal uptake of the GFP loaded nanocarrier was mediated by a C-end Rule (CendR) internalizing peptide fused to the GFP. Focused femtosecond pulsed-laser excitation triggered protein release from the nanocarrier and endosome disruption, and the released protein was capable of targeting the nucleoli, a model intracellular organelle. We further demonstrate the generality of the approach by loading and releasing Sox2 and p53. This method for targeting of individual cells, with resolution similar to microinjection, provides spatial and temporal control over protein delivery.

Efficient intracellular delivery of molecules with high cell viability using nanosecond-pulsed laser-activated carbon nanoparticles

Conventional physical and chemical methods that efficiently deliver molecules into cells are often associated with low cell viability. In this study, we evaluated the cellular effects of carbon nanoparticles believed to emit photoacoustic waves due to nanosecond-pulse laser activation to test the hypothesis that this method could achieve efficient intracellular delivery while maintaining high cell viability. Suspensions of DU145 human prostate carcinoma cells, carbon black (CB) nanoparticles, and calcein were exposed to 5-9 ns long laser pulses of near-infrared (1064 nm wavelength) light and then analyzed by flow cytometry for intracellular uptake of calcein and cell viability by propidium iodide staining. We found that intracellular uptake increased and in some cases saturated at high levels with only small losses in cell viability as a result of increasing laser fluence, laser exposure time, and as a unifying parameter, the total laser energy. Changing interpulse spacing between 0.1 and 10 s intervals showed no significant change in bioeffects, suggesting that the effects of each pulse were independent when spaced by at least 0.1 s intervals. Pretreatment of CB nanoparticles to intense laser exposure followed by mixing with cells also had no significant effect on uptake or viability. Similar uptake and viability were seen when CB nanoparticles were substituted with India ink, when DU145 cells were substituted with H9c2 rat cardiomyoblast cells, and when calcein was substituted with FITC-dextran. The best laser exposure conditions tested led to 88% of cells with intracellular uptake and close to 100% viability, indicating that nanosecond-pulse laser-activated carbon nanoparticles can achieve efficient intracellular delivery while maintaining high cell viability.

Therapy effects of gold nanorods on the CNE-1 nasopharyngeal carcinoma cell line

The use of nanocarriers to deliver drugs to tumor tissue is one of the most important strategies in cancer therapeutics. Recently, gold nanorods (GNRs) have begun to be used in cancer therapy because of their unique properties. The purpose of this study was to show the potential that GNRs have against human nasopharyngeal carcinoma CNE-1 cells, using near-infrared (NIR) laser light. Transmission electron microscopic and ultraviolet-visible spectroscopic investigations confirmed the efficient uptake of the GNRs by CNE-1 and human rhinal epithelia cells. The in vitro NIR photothermal therapy for the CNE-1 and rhinal epithelia cells was designed in three groups: (1) control, (2) laser alone, and (3) GNRs with laser. Fluorescence microscopy images indicated that, at some GNR concentrations and some intensities of NIR laser, GNRs with laser therapy could induce cell death for CNE-1 cells while keeping the rhinal epithelia cells healthy. Therefore, the results of this study suggest that using GNRs with NIR laser therapy can selectively destruct CNE-1 cells while having no effect on normal (rhinal epithelia) cells.

Hollow copper sulfide nanoparticle-mediated transdermal drug delivery

A photothermal ablation-enhanced transdermal drug delivery methodology is developed based on hollow copper sulfide nanoparticles (HCuSNPs) with intense photothermal coupling effects. Application of nanosecond-pulsed near-infrared laser allows rapid heating of the nanoparticles and instantaneous heat conduction. This provides very short periods of time but extremely high temperatures in local regions, with focused thermal ablation of the stratum corneum. The depth of skin perforations can be controlled by adjusting the laser power. Skin disruption by HCuSNP-mediated photothermal ablation significantly increases the permeability of human growth hormone. This technique offers compelling opportunities for macromolecular drug and vaccine delivery.

Objective assessment of skin rejuvenation using near-infrared 1064-nm neodymium: YAG laser in Asians

BACKGROUND

We reported previously that near-infrared (NIR) irradiation provides long-lasting stimulation of elastin, and is efficient for skin rejuvenation. Many studies have indicated the efficacy of various types of laser, but did not include sufficiently objective evaluation. Therefore, we evaluated the efficacy of NIR laser treatment not only subjectively but also objectively.

METHODS

Fifty Japanese patients were treated with a NIR 1064-nm neodymium: YAG laser. Objective computer assessments were performed by Canfield VISIA Complexion Analysis for improvement of dilated pores, skin texture, and wrinkles. The volunteers then provided subjective assessments. Histological evaluations of elastin were performed by Victoria blue staining up to 90 days post-treatment in four Japanese volunteers.

RESULTS

Mean pretreatment percentiles of dilated pores, skin texture, and wrinkles were 51.08 ± 24.82, 54.7 ± 26.33, and 58.02 ± 28.61, respectively. Mean post-treatment percentiles of dilated pores, skin texture, and wrinkles were 53.58 ± 23.89, 58.58 ± 24.44, and 62.2 ± 25.39, respectively. All objective computer assessments evaluated by percentiles in dilated pores, skin texture, and wrinkles showed significant improvement after NIR laser treatment. Ninety-six percent, 100%, and 98% of volunteers reported satisfaction with the improvement of dilated pores, skin texture, and wrinkles, respectively. NIR laser treatment appeared to increase the amount of elastin at day 30, which then decreased slightly but was still elevated at day 90 compared with nonirradiated controls on day 0. Thickening of the epidermis was detected on day 30, and epidermal smoothness persisted for up to 90 days. No treatment-related adverse events were observed.

CONCLUSIONS

NIR irradiation increased elastin in the dermis, and achieved skin rejuvenation. The results indicated that NIR irradiation provides safe and effective long-term stimulation of elastin, which is beneficial for improving dilated pores, skin texture, and wrinkles.