Infrared Laser Research Articles

Processing Solid Hydrogels into Hollow Structures by Infrared Laser Light for Highly-Efficient Drug Loading and Controlled Release.

Hollow hydrogels, characterized by their three-dimensional networks akin to biological tissues, are extensively utilized in artificial blood vessels, drug delivery, and nerve conduits due to their superior biocompatibility and fluid-transportation capacity. Nonetheless, the fabrication of hollow hydrogels presents significant challenges, including intricate steps, costly equipment, and structural instability. Consequently, refining the preparation techniques for hollow hydrogels remains paramount to surmounting the limitations of conventional methods. This research introduces an innovative approach that markedly diverges from traditional techniques, offering notable convenience and efficiency in the creation of hollow hydrogel structures. The central novelty of this method lies in employing laser light to induce an in situ photothermal effect, leading to the formation of hollow configurations. This laser-driven transformation of solid hydrogels into hollow structures addresses numerous shortcomings associated with traditional methods. For instance, conventional chemical approaches often necessitate several days to yield hollow hydrogels, and the resultant structures tend to be fragile and susceptible to damage under external pressure. In contrast, the laser-assisted technique facilitates the formation of hollow structures within 240 s, significantly outpacing traditional methods. To achieve controlled drug release, silk fibroin was integrated into the wall of the hollow hydrogels, enabling modulation of wall permeability and directing the drug release process.

3D-Printed hydrogel scaffolds with drug- and stem cell-laden core/shell filaments for cancer therapy and soft tissue repair.

Treatment of local tumor recurrence and repair of the tissue defects after tumorectomy still remain clinical challenges. Currently, controlled release of therapeutic drugs is one of the widely used approaches to kill the residual and recurrent cancer cells, and stem cell-laden hydrogel scaffolds are promising candidates for soft tissue repair. However, hydrogel scaffolds with the bifunction of controlled release of therapeutic drugs for cancer therapy and loading stem cells for tissue repair are still not well established. In this study, we fabricated a biphasic hydrogel scaffold containing two types of core/shell filaments with drugs and stem cells loaded in the core part of these two filaments. Black phosphorus nanosheets were added to alginate (the shell layer) in the drug-loaded filament, endowing the scaffold with a photothermal effect under near infrared (NIR) laser irradiation. Moreover, NIR could trigger the drug release from the core/shell filaments to achieve photothermal-chemotherapy of cancer. Additionally, stem cells embedded in the core parts of the other filaments could maintain high cell viability due to the protection of the shell layer (pure alginate), which promoted soft tissue regeneration in vivo. Thus, the prepared biphasic scaffold with drug- and stem cell-laden core/shell filaments may be a potential candidate to fill the tissue defects after the surgical resection of tumors to kill the residual and recurrent cancer and repair the tissue defects.

Effect of IR Laser Energy on Several Polymers Using LIBS Analysis

ABSTRACTThe focus of this research is to use the thermal ablation properties of a Nd:YAG infrared laser to highlight the thermal damage caused by the extinction of the plasma, which leads to the disappearance of the spectra of certain polymers as the laser energy increases. The study involved testing five commonly used polymers: polytetrafluoroethylene (PTFE) also known as Teflon, polyoxymethylene (POM), polyvinyl chloride (PVC), Bakelite, and polyamide. Laser induced breakdown spectroscopy (LIBS) analysis was used to qualitatively analyze the plasma generated from the polymer samples, identifying the excited species present in each of the five polymers. Wavelength dispersive X‐ray fluorescence (WDXRF) analysis of the polymer samples further confirmed the identification of these excited species. The results obtained from the spectra recorded at different laser energies in an air environment showed that the saturation observed in the plasma, induced by increasing laser energy, is not consistently observed for all polymers. This plasma extinction phenomenon in certain polymers is attributed to thermal effects when using an infrared (IR) laser as a heating source.

Electrochemical CO2 Reduction in Acidic Electrolytes: Spectroscopic Evidence for Local pH Gradients.

Inspired by recent advances in electrochemical CO2 reduction (CO2R) under acidic conditions, herein we leverage in situ spectroscopy to inform the optimization of CO2R at low pH. Using attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and fluorescent confocal laser scanning microscopy, we investigate the role that alkali cations (M+) play on electrochemical CO2R. This study hence provides important information related to the local electrode surface pH under bulk acidic conditions for CO2R, both in the presence and absence of an organic film layer, at variable [M+]. We show that in an acidic electrolyte, an appropriate current density can enable CO2R in the absence of metal cations. In situ local pH measurements suggest the local [H+] must be sufficiently depleted to promote H2O reduction as the competing reaction with CO2R. Incrementally incorporating [K+] leads to increases in the local pH that promotes CO2R but only at proton consumption rates sufficient to drive the pH up dramatically. Stark tuning measurements and analysis of surface water structure reveal no change in the electric field with [M+] and a desorption of interfacial water, indicating that improved CO2R performance is driven by suppression of H+ mass transport and modification of the interfacial solvation structure. In situ pH measurements confirm increasing local pH, and therefore decreased local [CO2], with [M+], motivating alternate means of modulating proton transport. We show that an organic film formed via in situ electrodeposition of an organic additive provides a means to achieve selective CO2R (FECO2R ∼ 65%) over hydrogen evolution reaction in the presence of strong acid (pH 1) and low cation concentrations (≤0.1 M) at both low and high current densities.

Effects of Local Anesthetics on Tissue Penetration Using Diode Lasers in Intraoral Tissues.

Objective: The purpose of this study was to demonstrate heat transfer within oral soft tissues using different lasers under the effect of local anesthetics (LA). Methods: Bovine tongue slices were placed in between two glass slides and at a distance from a thermographic camera. In total, 2-cm-long 240 incisions were made along the surface of the tissue parallel to glass slides and the camera capture field. Incisions were performed using 445-nm and infrared (IR) lasers (970 nm and 980 nm on a continuous wave at 2 W) with 320 µm-initiated (concentrated energy at the tip provided by a blue articulated paper and laser irradiation) and noninitiated (defused energy) fiber (30-sec irradiation period). LA was injected into the specimens before irradiation. The temperature changes in °C (ΔT) and vertical and lateral heat transfer (in mm) were recorded at 10-sec intervals for 30 sec, using thermographic images. The amount of lateral and vertical heat transfer was measured. A repeated analysis of variance statistical comparison test was used to analyze differences between the lateral (width) and the vertical (height) heat transfer for initiated and noninitiated lasers and different lasers. Results: The maximum ΔT in °C utilizing initiated tips of 970, 980, or 445 nm were 11.82 ± 3.46, 7.66 ± 3.24, and 18.94 ± 7.01 and using noninitiated tips were 8.27 ± 1.69, 8.87 ± 2.40, and 12.31 ± 8.65, respectively. Heat transfers (height/width) for initiated were 40.65 ± 10.40/90.65 ± 10.77 mm, 41.50 ± 11.83/83.95 ± 11.20 mm, and 33.70 ± 9.10/95.10 ± 11.17 mm and for noninitiated lasers were 52.95 ± 6.89/96.10 ± 11.17 mm, 47.75 ± 7.41/93.75 ± 14.96 mm, and 31.35 ± 11.40/75.20 ± 19.68 mm, respectively. A statistically significant difference was found between all lasers (p < 0.05) for initiated and noninitiated lasers (except for 970/980 nm for noninitiated lasers). Lower penetration depth (p < 0.05) at 445-nm diode and greater lateral heat spreading (p < 0.05) were identified under LA especially utilizing noninitiated tips without significant difference in IR lasers. Conclusions: LA might negatively influence soft tissues creating scattering when noninitiated tips are used and IR diode laser technology.

A tutorial on optical photothermal infrared (O-PTIR) microscopy.

This tutorial reviews the rapidly growing field of optical photothermal infrared (O-PTIR) spectroscopy and chemical imaging. O-PTIR is an infrared super-resolution measurement technique where a shorter wavelength visible probe is used to measure and map infrared (IR) absorption with spatial resolution up to 30× better than conventional techniques such as Fourier transform infrared and direct IR laser imaging systems. This article reviews key limitations of conventional IR instruments, the O-PTIR technology breakthroughs, and their origins that have overcome the prior limitations. This article also discusses recent developments in expanding multi-modal O-PTIR approaches that enable complementary Raman spectroscopy and fluorescence microscopy imaging, including wide-field O-PTIR imaging with fluorescence-based detection of IR absorption. Various practical subjects are covered, including sample preparation techniques, optimal measurement configurations, use of IR tags/labels and techniques for data analysis, and visualization. Key O-PTIR applications are reviewed in many areas, including biological and biomedical sciences, environmental and microplastics research, (bio)pharmaceuticals, materials science, cultural heritage, forensics, photonics, and failure analysis.

TW-scale few-cycle short-wave infrared laser based on nonlinear compression in a large-core gas-filled hollow core fiber

In this Letter, we present the generation of terawatt-scale few-cycle short-wave infrared (SWIR) lasers using nonlinear compression in a large-core gas-filled hollow core fiber. Through the experimental verification, we investigate the energy scaling properties and nonlinear pulse propagation in the argon-filled hollow core fiber. At static pressure, the system delivers pulses with 5.55 mJ/9.04 fs at a central wavelength of 1.45 μm, resulting in a peak power of about 0.5 TW. Subsequently, based on the chirped input pulses and pressure gradient, the system delivers terawatt-scale two-cycle SWIR pulses with 9.52 mJ/10.65 fs, resulting in a record peak power of about 0.7 TW. This study marks a crucial advancement in the field of SWIR ultra-intense, ultrashort pulse nonlinear interaction platforms. This high-energy, few-cycle SWIR source has significant applications in high-intensity THz radiation, x-ray generation, and other fields of strong-field physics.

Hydrogen/Deuterium Exchange Reaction Rate of Cytochrome c Determined by Droplet Collision Atmospheric Pressure Infrared Laser Ablation Mass Spectrometry.

The hydrogen/deuterium (H/D) exchange rate is an optimal measure for studying the structures and dynamics of hydrogen bonding systems, as it reflects the molecular contact environment and the strength of the hydrogen bonds. A method for rapid measurement of the H/D exchange reaction rates is required to examine the intermolecular environments of molecules in solutions. We developed a droplet collision atmospheric pressure infrared laser ablation mass spectrometry technique for this purpose. We obtained the H/D exchange reaction rate of cytochrome c in a methanol/H2O·D2O solution. We revealed that the first hydration shell of the cytochrome c molecule hinders the penetration of D2O to the surface of the molecule from the rates, which provides a novel method to investigate solution structures by a mass-spectrometric method. The droplet-collision mass spectrometry method developed in the present study can be extended to research on the molecular interactions in solutions, such as the mutual interactions of protein molecules, which are of importance in living cells.

Gasb-to-Si Direct Wafer Bonding and Thermal Budget Considerations for Photonic Applications

Extensive progress has been made in recent years in heterogeneous integration (HI) of III-V materials on Si photonics wafers [1], including direct chip-to-chip bonding of GaSb-based infrared (IR) lasers [2], greatly expanding the application space and performance of either material system on its own. This includes active research at Sandia National Labs developing lasers based on GaAs, GaSb, GaN, and InP substrates directly integrated with silicon photonics at the chip and wafer scale. A “device last” process flow is desirable in this case both for scalability and because of the tight alignment tolerance required between the Si waveguides and active III-V laser elements to optimally couple light between the III-V and the Si. In this process flow, the Si photonics wafer is fabricated separately before bonding with an unpatterned III-V wafer or chip. The III-V laser is then defined after bonding, allowing lithographic registration to Si photonics structures. Thus, preparation of both semiconductor surfaces and preservation of the bond between them become critical for device performance and constrain subsequent process steps. Here, we focus on GaSb-based devices.The first consideration is preparing the GaSb and Si surfaces for bonding. Argon sputtering to prepare the GaSb surface for bonding to Si has been investigated, though the emphasis was on GaSb surface roughness, bonding temperature, and electronic transport through the interface [3]. Here, we use x-ray photoelectron spectroscopy (XPS) to investigate the impact of the GaSb oxide composition on the quality of the bond to oxidized Si wafers. In Fig. 1(a)-(c) we use confocal scanning acoustic microscopy (CSAM) to compare as-received 3” GaSb substrates with and without chemical oxide removal to epitaxial GaSb. In the CSAM images, dark areas indicate bond adhesion. We find that bonding improves with decreasing Ga-oxide content realized on the epitaxial GaSb.The second consideration is constraining the laser process steps in order to preserve the bond between the Si photonics and GaSb wafers. Our HI process steps involving GaSb thinning and substrate removal have been described elsewhere [4], though investigation of the thermal budget for survival of the direct GaSb/Si bond through a laser fabrication process flow is lacking in the literature. As the thermal expansion coefficient of GaSb is approximately three times that of Si, temperatures must be limited to prevent the GaSb from expanding excessively and delaminating from the Si wafer when running the III-V laser fabrication after integration with the Si photonics wafer. We investigate the robustness of the bond between epitaxial GaSb and the Si photonics wafer through cross-sectional transmission electron microscopy (TEM) of the bond interface after various process steps typical to laser fabrication and the implications of the thermal budget on these process steps. For example, we find that extended periods of time (more than an hour) at 250°C, which is typical for chemical vapor deposition (CVD) of SiO2 or Si3N4, cause the thinned III-V wafer to delaminate from the Si photonics wafer. While we don’t observe destructive delamination at lower processing temperatures, high-angle annular dark-field imaging (HAADF) analysis in Fig. 1(d) shows significant Sb diffusion into the Si photonics native SiO2 layer.In summary, for optimal performance of GaSb-based hybrid lasers directly bonded to Si photonics, understanding and preserving the bond between these materials is critical. These considerations include minimizing the Ga-oxide at the GaSb surface prior to bonding to promote bond success and keeping extended thermal processes below 250°C to maintain the bond between the GaSb and the Si photonics wafers. These results will inform processes required for full laser fabrication flow, particularly in steps that traditionally require higher or longer temperature parameters.SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.[1] D. Caimi, et al., IEEE Trans. Elect. Dev. 68, p. 3149 (2021).[2] A. Spott, et al., Optica 5, p. 996 (2018).[3] F. Predan, et al., Appl. Surf. Scie., 353, p. 1203 (2015).[4] M. Wood, et al., in CLEO 2023 Technical Digest Series, STh3H.5 (2023). Figure 1

(Invited) Single-Molecule Electroluminescence Triggered by Field-Driven Tunneling Electrons

Exciton dynamics governs versatile functions of molecules such as photon emission, photovoltaic and photo chemical reactions. For clarifying the dynamics of excitons in a molecule, an optical measurement with high spatiotemporal resolution is required because the excitons have short lifetimes and their behavior in the local region is important for optical properties. Luminescence spectroscopy based on a scanning tunneling microscope (STM) enable to investigate optical properties with sub-nanometer spatial resolution[1-2]. In this method, scanning tunneling luminescence (STL) spectroscopy, a molecule is excited by the tunneling current of an STM, which can be controlled with atomic spatial resolution. In contrast, the time resolution of STL spectroscopy is limited, because the tunnel current is controlled by electrical circuits. Therefore, this method cannot be used to track the picosecond dynamics of excitons. For overcoming the time-resolution of STL, we have combined a single-cycle terahertz (THz) pulse with STL spectroscopy. By coupling the THz pulse to a tip of an STM, the photoelectric field of THz pulse with sub picosecond time width is confined to the tip apex, which enables to manipulate the tunneling electrons with high spatiotemporal resolutions[4-9]. In this work, we succeeded in forming an exciton in a single molecule by using THz-field-driven current and clarifying the mechanism of the exciton formation.Single-cycle THz pulses were generated by using optical rectification of near infrared (NIR) laser pulses from a Yb fiber laser using a tilted-pulse-front configuration (Fig. 1a). The generated THz pulses were guided into the STM chamber and focused by using a lens near the tip. We prepared a clean Ag(111) surface and deposited NaCl films. Then, we deposited Pd phthalocyanine (PdPc) molecules on the NaCl/Ag(111) surface. Figure 1b shows THz-STL spectra of a PdPc on NaCl/Ag(111). Several sharp peaks appeared at around 1.9 eV in the red spectrum (with THz irradiation) and no peak appeared in the gray spectrum (without THz). The peak energy of the main peak is identical to the fluorescence peak of a PdPc measured by conventional STL[3], thus we concluded that the singlet excited state was formed by THz-field-driven tunneling. In this presentation, we would like to discuss the detailed mechanism for the exciton formation in a molecule by THz-field-driven electrons.[1] H. Imada et al., Nature 538, 364 (2016). [2] K. Kimura et al., Nature 570, 210 (2019). [3] S. Cao et al., Nat. Chem. 13, 766 (2021). [4] T. L. Cocker et al., Nat. Photon. 7, 620 (2013). [5] K. Yoshioka et al., Nat. Photon. 10, 762 (2016). [6] V. Jelic et al., Nature Physics 13, 591 (2017). [7] D. Peller et al., Nature 585, 58 (2020). [8] L. Wang 376, 401 (2022). [9] K. Kimura et al., ACS photon. 8, 982 (2021). Figure 1

Light-activated nanoclusters with tunable ROS for wound infection treatment

Infected wounds pose a significant clinical challenge due to bacterial resistance, recurrent infections, and impaired healing. Reactive oxygen species (ROS)-based strategies have shown promise in eradicating bacterial infections. However, the excess ROS in the infection site after treatments may cause irreversible damage to healthy tissues. To address this issue, we developed bovine serum albumin-iridium oxide nanoclusters (BSA-IrOx NCs) which enable photo-regulated ROS generation and scavenging using near infrared (NIR) laser. Upon NIR laser irradiation, BSA-IrOx NCs exhibit enhanced photodynamic therapy, destroying biofilms and killing bacteria. When the NIR laser is off, the nanoclusters' antioxidant enzyme-like activities prevent inflammation and repair damaged tissue through ROS clearance. Transcriptomic and metabolomic analyses revealed that BSA-IrOx NCs inhibit bacterial nitric oxide synthase, blocking bacterial growth and biofilm formation. Furthermore, the nanoclusters repair impaired skin by strengthening cell junctions and reducing mitochondrial damage in a fibroblast model. In vivo studies using rat infected wound models confirmed the efficacy of BSA-IrOx NCs. This study presents a promising strategy for treating biofilm-induced infected wounds by regulating the ROS microenvironment, addressing the challenges associated with current ROS-based antibacterial approaches.

Construction of a MoS2@mSiO2 nanocarrier as a near-infrared/pH dual-responsive platform to control the drug release for anti-tumor

Designing new-type nanosystems to realize the combination of multiple treatment is an efficient routine to enhance the anti-tumor efficacy in clinic. In this study, molybdenum disulfide (MoS2) was selected as a photothermal agent, and mesoporous silica (mSiO2) was coated on the surface of MoS2 using the solvothermal and template removal methods. The chemotherapeutic drug doxorubicin hydrochloride (DOX) as a model drug was then loaded into the above MoS2@mSiO2 nanocarrier to prepare the tumor-targeting MoS2@mSiO2-DOX nanosystem. XRD, UV–Vis, FTIR, SEM, TEM, and DLS results jointly confirmed that the MoS2@mSiO2-DOX nanosystem with a particle size of approximately 370 nm was successfully synthesized. The XPS and BET analysis identified that the outer layer of MoS2@mSiO2 nanocarrier was SiO2, which has a large surface area of 99.41 m2/g with an average pore size of 3.5 nm coated on the MoS2. The in-vitro cytotoxicity and photothermal performance of the MoS2@mSiO2 nanodrug delivery system was tested, and the results show that MoS2@mSiO2 has a low toxicity to normal human liver cells (HL-7702), and which also exhibits a good photothermal stability with a photothermal conversion efficiency of 28.8%. With the aid of the large specific surface area of mSiO2 and the opposite zeta potential, a high amount of DOX was loaded on MoS2@mSiO2 nanocarrier, and the measured loading efficiency of DOX can reach up to 48.87%. The 48 h-drug release rate of MoS2@mSiO2-DOX reaches 35.65% under the conditions of near infrared (NIR) laser irradiation at pH=5.0, which is nearly 5 times higher than that of 6.26% under the normal physiological environment (pH=7.4 without NIR laser irradiation), indicating that the MoS2@mSiO2-DOX nanosystem possesses obvious pH and NIR laser responsive release characteristics. The MoS2@mSiO2 nanocarrier has good cytocompatibility, outstanding photothermal conversion and drug loading properties, and after DOX adsorption, the system exhibits excellent pH and laser responsive drug controlled release performance, which is expected to be widely used in the field of combining the photothermal-chemotherapy to synergistically resist tumor.

Electron Microscopy on Mechanism of Voidage and Cracking in Si by Injection of a Permeable Infra-Red Laser

Electron Microscopy on Mechanism of Voidage and Cracking in Si by Injection of a Permeable Infra-Red Laser

Investigations on MoS2 plasma by infra-red pulsed laser irradiation in high vacuum

MoS2 targets were irradiated by infra-red (IR) pulsed laser in a high vacuum to determine hot plasma parameters, atomic, molecular and ion emission, and angular and charge state distributions. In this way, pulsed laser deposition (PLD) of thin films on graphene oxide substrates was also realized. An Nd:YAG laser, operating at the 1064 nm wavelength with a 5 ns pulse duration and up to a 1 J pulse energy, in a single pulse or at a 10 Hz repetition rate, was employed. Ablation yield was measured as a function of the laser fluence. Plasma was characterized using different analysis techniques, such as time-of-flight measurements, quadrupole mass spectrometry and fast CCD visible imaging. The so-produced films were characterized by composition, thickness, roughness, wetting ability, and morphology. When compared to the MoS2 targets, they show a slight decrease of S with respect to Mo, due to higher ablation yield, low fusion temperature and high sublimation in vacuum. The pulsed IR laser deposited MoS x (with 1 < x < 2) films are uniform, with a thickness of about 130 nm, a roughness of about 50 nm and a higher wettability than the MoS2 targets. Some potential applications of the pulsed IR laser-deposited MoS x films are also presented and discussed.

Prussian blue-decorated indocyanine green-loaded mesoporous silica nanohybrid for synergistic photothermal-photodynamic-chemodynamic therapy against methicillin-resistant Staphylococcus aureus

Nanomaterial-based synergistic antibacterial agents are considered as promising tools to combat infections caused by antibiotic-resistant bacteria. Herein, multifunctional mesoporous silica nanoparticle (MSN)-based nanocomposites were fabricated for synergistic photothermal/photodynamic/chemodynamic therapy against methicillin-resistant Staphylococcus aureus (MRSA). MSN loaded with indocyanine green (ICG) as a core, while Prussian blue (PB) nanostructure was decorated on MSN surface via in situ growth method to form a core-shell nanohybrid (MSN-ICG@PB). Upon a near infrared (NIR) laser excitation, MSN-ICG@PB (200 μg mL−1) exhibited highly efficient singlet oxygen (1O2) generation and hyperthermia effect (48.7℃). In the presence of exogenous H2O2, PB with peroxidase-like activity promoted the generation of toxic hydroxyl radicals (•OH) to achieve chemodynamic therapy (CDT). PTT can greatly increase the permeability of bacterial lipid membrane, facilitating the generated 1O2 and •OH to kill bacteria more efficiently. Under NIR irradiation and exogenous H2O2, MSN-ICG@PB (200 μg mL−1) with good biocompatibility exhibited a synergistic antibacterial effect against MRSA with high bacterial killing efficiency (>98 %). Moreover, due to the synergistic bactericidal mechanism, MSN-ICG@PB with satisfactory biosafety makes it a promising antimicrobial agent to fight against MRSA.

Biomimetic gold nanocages incorporating copper-human serum albumin for tumor immunotherapy via cuproptosis-lactate regulation

Cancer immunotherapy remains a significant challenge due to insufficient proliferation of immune cells and the sturdy immunosuppressive tumor microenvironment. Herein, we proposed the hypothesis of cuproptosis-lactate regulation to provoke cuproptosis and enhance anti-tumor immunity. For this purpose, copper-human serum albumin nanocomplex loaded gold nanocages with bacterial membrane coating (BAu-CuNCs) were developed. The targeted delivery and disassembly of BAu-CuNCs in tumor cells initiated a cascade of reactions. Under near infrared (NIR) laser irradiation, the release of copper-human serum albumin (Cu-HSA) was enhanced that reacted with intratumoral glutathione (GSH) via a disulfide exchange reaction to liberate Cu2+ ions and exert cuproptosis. Subsequently, the cuproptosis effect triggered immunogenic cell death (ICD) in tumor by the release of damage associated molecular patterns (DAMPs) to realize anti-tumor immunity via robust production of cytotoxic T cells (CD8+) and helper T cells (CD4+). Meanwhile, under NIR irradiation, gold nanocages (AuNCs) promoted excessive reactive oxygen species (ROS) generation that played a primary role in inhibiting glycolysis, reducing the lactate and ATP level. The combine action of lower lactate level, ATP reduction and GSH depletion further sensitized the tumor cells to cuproptosis. Also, the lower lactate production led to the significant blockage of immunosuppressive T regulatory cells (Tregs) and boosted the anti-tumor immunity. Additionally, the effective inhibition of breast cancer metastasis to the lungs enhanced the anti-tumor therapeutic impact of BAu-CuNCs + NIR treatment. Hence, BAu-CuNCs + NIR concurrently induced cuproptosis, ICD and hindered lactate production, leading to the inhibition of tumor growth, remodeling of the immunosuppressive tumor microenvironment and suppression of lung metastasis. Therefore, leveraging cuproptosis-lactate regulation, this approach presents a novel strategy for enhanced tumor immunotherapy.

Exploring the impact of high-power infrared lasers on electro-optical systems performance: A field study with different wavelengths

The performance of different electro-optical (EO) and infrared (IR) imaging systems under the impact of high-power pulsed infrared lasers has been well evaluated and studied. The infrared lasers operating at 1.06 µm, 3.7–4.2 µm, and 9.6 μm wavelengths, including short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR) sensors used in television, infrared imaging, and tracking systems. Our research is focused on the intended waveband of the infrared imagers at significant distances relevant to tactical security operations, with a range of 6 km–10 km. The study compares the effects of both dazzling and damaging laser radiation on EO systems using a straightforward theoretical framework supported by atmospheric modeling. It was observed that increased humidity and temperature diminish both dazzling and damage distances, with less impact at 1.06 µm and more significant at 9.6 µm, compared to 3.7–4.2 µm. The effect of atmospheric conditions on IR laser energy was studied using MODTRAN software to determine the effective laser parameters for EO imaging systems at different distances. The study also investigates the critical parameters of practical high-power pulsed infrared laser wavelengths to dazzle and damage imaging systems at different distances. Field investigations revealed that dazzling on TV seekers can extend beyond 10 km by 1.06 µm, with damages up to 8 km, depending on the sensor field of view, laser source pulse frequency, and environmental conditions. Lasers with wavelengths of 3.7–4.2 μm can produce high-dazzling spots at the center of images of MWIR seekers up to 6 km. Lasers with wavelengths of 9.6 μm can rapidly damage LWIR seekers’ pixels due to their varied energy outputs and pulse frequency-range responses up to 8 km. System functions were lost under the dazzling and damaging effects. The study revealed a strong correlation between experimental results and predictions, with a strong agreement between experimental and theoretical effective distances under similar environmental and atmospheric conditions.

3D Printing of Succulent‐Inspired Microneedle Array for Enhanced Tissue Adhesion and Controllable Drug Release

AbstractControllable and long‐term release remains a great challenge in current drug delivery systems. Benefiting from their efficient drug loading and painless administration, microneedles (MNs) have emerged as a promising platform for transdermal drug delivery, while they often fail to achieve long‐term tissue adhesion and controllable extended drug release. Here, 3D printing of an innovative MN patch is presented with succulent‐inspired responsive microstructures and light‐controllable long‐term release capability. The MN exhibits a reversible shrink‐swell volume change behavior in response to surrounding humidity, which enables sufficient mechanical strength for skin penetration under the shrinkage conditions and efficient long‐term adhesion when swollen in skin tissues. Moreover, the MN patch introduces a controllable long‐term drug release system, achieved through the integration of thiolated heparin (Hep‐SH) for sustained growth factor release and graphene oxide (GO) nanosheets for controlled drug release via near infrared (NIR) laser irradiation. The MN patches with growth factor loading have good biocompatibility and can promote the proliferation, migration, and proangiogenesis of endothelial cells is further demonstrated. Thus, it is believed that such flexible MN patches can be promising candidates for controllable long‐term transdermal drug delivery as well as other related tissue engineering applications.

Weldability and Mechanical Properties of Pure Copper Foils Welded by Blue Diode Laser.

The need to manufacture components out of copper is significantly increasing, particularly in the solar technology, semiconductor, and electric vehicle sectors. In the past few decades, infrared laser (IR) and green laser (GL) have been the primary technologies used to address this demand, especially for small or thin components. However, with the increased demand for energy saving, alternative joint techniques such as blue diode laser (BDL) are being actively explored. In this paper, bead-on-plate welding experiments on 0.2 mm thick pure copper samples employing a BDL are presented. Two sets of parameters were carefully selected in this investigation, namely Cu-1: Power (P) = 200 W; Speed (s) = 1 mm/s; and angle = 0°, and Cu-2: P = 200 W; s = 5 mm/s; and angle = 10°. The results from both sets of parameters produced defect-free full penetration welds. Hardness test results indicated relatively softer weld zones compared with the base metal. Tensile test samples fractured in the weld zones. Overall, the samples welded with Cu-1 parameters showed better mechanical properties, such as strength and elongation, than those welded with the Cu-2 parameters. The tensile strength and elongation obtained from Cu-1 were marginally lower than those of the unwelded pure copper. The outcomes from this research provide an alternative welding technique that is able to produce reliable, strong, and precise joints, particularly for small and thin components, which can be very challenging to produce.

Comparison of Blue and Infrared Light Transmission Through Dental Tissues and Restorative Materials.

The depth of cure using blue-light photocuring units (BL) is limited by tooth structure and qualities of the restorative material through which the activating wavelength must pass. Recent developments incorporate an infrared (IR) activated upconversion (UC) fluorescence of a lining agent filled with nanocrystals of NaYF4 and doped with YB+3 and Tm+3 that emit both blue and violet light locally at the interface of the liner and restorative resin. The purpose of this study was to evaluate the BL and 975 nm infrared (IR) light power transmission through dental tissues and restorative materials. Power transmissions of the IR laser (975 nm) and a monowave blue-only light-curing unit (Bluephase 16i) through dental tissues (enamel, dentin, and enamel/dentin junction, or DEJ), eight (8) various dental resin composites, and eight (8) dental ceramics, each at four thicknesses (1, 2, 3 and 4 mm) were evaluated (n=5) using a thermopile sensor (PM10, Coherent Inc) connected to a laser power meter (Fieldmate, Coherent Inc). Power transmission values of each light source and restorative material were subjected to analysis of variance and Tukey test at a pre-set alpha of 0.05. A linear correlation (r=0.9884) between the supplied current and emitted IR power of the laser diode was found, showing no statistical power reduction with increased distances (collimated beam). For tooth tissues, the highest power transmissions for both light sources were observed using 1.0 mm enamel while the lowest values were found for 2.0 mm dentin and an association of 2.0 mm DEJ and 1.0 mm dentin. The only group where IR demonstrated significantly higher transmission when compared to BL was 1.0 mm enamel. For all resin composites and dental ceramics, increased thickness resulted in a reduction of IR power transmission (except for EverX Posterior fiber-reinforced composite and e.max HT ceramic). IR resulted in higher transmission through all resin composites, except for Tetric EvoCeram White. The highest BL transmission was observed for SDR Flow, at all thicknesses. Higher IR/BL ratios were observed for EverX Posterior, Herculite Ultra, and Lava Ultimate, while the lowest ratio was observed for Tetric EvoCeram White. Reduced translucency shades within the same material resulted in lower power ratio values, especially for BL transmission. Higher IR/BL ratios were observed for e.Max LT, VitaVM7 Base Dentin, and e.max CAD HT, while the lowest values were found for VitaVM7 Enamel and Paradigm C. IR power transmission through enamel was higher when compared to blue light, while no difference was observed for dentin. The power transmission of IR was higher than BL for resin composites, except for a high value and low chroma shade. Fiber-reinforced resin composite demonstrated the highest IR/BL power transmission ratio. A greater IR/BL ratio was observed for lower translucency ceramics when compared to high translucency.