Laser Stimulation Research Articles

Abstract 1125: Percutaneous Optofluidic Catheter-guided Photo-triggered Nanogoldsomes Reduce Infarct Size And Mitigate Myocardial Dysfunction In A Swine Model Of Acute Myocardial Infarction

Introduction: S-nitrosoglutathione (GSNO) is an endogenous S-nitrosothiol that plays important roles in nitric oxide (NO) generation and signaling. We previously designed an Au-polymersomes/GSNO nanoparticle (nanogoldsome) that can be triggered by laser or ultrasound to accelerate the release of NO, which effectively dilates the arteries of the target organ and induces anti-apoptotic protection against ischemia-reperfusion injury. In this study we integrated an optofluidic coronary catheter with the photo-triggered nanogoldsomes, and investigate their roles in mitigating the infarct size in a swine model of acute myocardial infarction (AMI). Methods: In a swine AMI model of 90 min coronary artery (CA) occlusion, nanogoldsomes (0.145 mg Au and 3.66 μg GSNO/kg) were administered 5 min after balloon-off using a percutaneous coronary optofluidic catheter with 532 nm laser stimulation at the tip. The CA diameter was measured at baseline and at 0 and 15 min of reperfusion. Left ventricular (LV) function (max dp/dt) were measured at baseline, and 1 h and 7 days after reperfusion. The infarct area was determined at day 7 using triphenyltetrazolium chloride stain with the infarct fraction calculated in reference to the area at risk stained by Evan’s blue coronary infusion with balloon occlusion at the same site. Results: Compared to AMI group, the CA diameter showed significant dilatation 10 min after nanogoldsome/laser treatment (1.22 vs. 0.98 folds, P < 0.05), while systemic blood pressure showed no significant drop. The infarct fraction was significantly reduced (49% vs. 73%, P < 0.05) and LV function markedly better 7 days after AMI. By contrast, no significant differences were noted in the control groups of GSNO (3.66 μg/kg) and nanogoldsomes without laser stimulation. Conclusion: Percutaneous optofluidic catheter-guided infusion of nanogoldsomes at coronary orifice with simultaneous tip laser stimulation in the first minutes of AMI reperfusion magnified NO release in the most critical reperfusion period. This instantly dilated coronary arteries, and reduced infarct area and mitigated LV dysfunction 7 days after AMI. With large animal experiments showing pathophysiological benefits, further translation to pre-clinical studies is encouraged.

Structural, optical and theoretical studies of 2,4-dichlorobenzoic acid benzamide in nonlinear optical applications using Z-scan technique

New organic 2,4-dichlorobenzoic acid benzamide co-crystal (DCBB) was successfully grown using slow evaporation solution growth technique. The formation of new DCBBco-crystals was taken and their structure and crystallinity were analyzed by single crystal and powder X-ray diffraction analyses. It shows that DCBB material in monoclinic structure with centrosymmetric space group of P21/c. The different vibrations, chemical bonding and chemical configuration of the co-crystal was studied through FTIR, Raman and 1H NMR spectroscopy. Optical transmittance is the basic requirement for the nonlinear optical application with a lower cutoff wavelength of about 320 nm as well as optical band gap value Eg is 3.84 eV. Photoluminescence spectrum showing two emission peaks of 403 and 550 nm by means of an excitation wavelength of 290 nm. The compound's thermal stability was up to 125 °C was analyzed by the thermal analysis. Vickers's micro hardness test was used for evaluating mechanical properties of DCBB, and the results showed that the material was classified as soft category (n = 2.54). Nonlinear optical characteristics of the sample under pulsed laser stimulation by Q-switched Nd:YAG laser with 532 nm wavelength. The presence of reverse saturable absorption peak exhibits 2-photon absorption process was confirmed by varying its intensity shows saturation intensity IS), nonlinear absorption coefficient (β) under pulse laser excitation. The optical limiting threshold determined by three different intensities were found to be 3.02×1012 (W/m2), 2.85×1012 (W/m2) and 1.44×1012 (W/m2) respectively. Theoretical investigations like density functional theory using B3LYP to calculate as well as determining non-linear optical characteristics of the DCBB complex.

Dual‐Functional X‐Ray Photochromic Phosphor: High‐Performance Detection and 3D Imaging

AbstractThis study explores the integration of X‐ray‐induced photochromism and photoluminescence in a single material, offering innovative multi‐mode applications in optical memory, anti‐counterfeiting, and X‐ray detection and imaging. The photochromic phosphor LiAlSi2O6:Sm3+ is synthesized, which undergoes a color change from white to dark green under bright field conditions and displays orange photoluminescence in dark field conditions after X‐ray exposure due to defect formation. The phosphor shows accelerated bleaching and recovery under 473 nm laser stimulation. The distinct X‐ray‐induced color contrast and luminescence intensity modification in LiAlSi2O6:Sm3+ highlight its potential in advanced luminescent material design. Moreover, a LiAlSi2O6:Sm3+‐based flexible film demonstrates “dual‐mode” 3D X‐ray imaging and detection capabilities, paving the way for future X‐ray detecting and imaging device research.

3F4 Hypergeometric Functions as a Sum of a Product of 2F3 Functions

This paper shows that certain 3F4 hypergeometric functions can be expanded in sums of pair products of 2F3 functions, which reduce in special cases to 2F3 functions expanded in sums of pair products of 1F2 functions. This expands the class of hypergeometric functions having summation theorems beyond those expressible as pair-products of generalized Whittaker functions, 2F1 functions, and 3F2 functions into the realm of pFq functions where p<q for both the summand and terms in the series. In addition to its intrinsic value, this result has a specific application in calculating the response of the atoms to laser stimulation in the Strong Field Approximation.

An Hsp70 promoter-based mouse for heat shock-induced gene modulation.

Physical therapy is extensively employed in clinical settings. Nevertheless, the absence of suitable animal models has resulted in an incomplete understanding of the in vivo mechanisms and cellular distribution that respond to physical stimuli. The objective of this research was to create a mouse model capable of indicating the cells affected by physical stimuli. In this study, we successfully established a mouse line based on the heat shock protein 70 (Hsp70) promoter, wherein the expression of CreERT2 can be induced by physical stimuli. Following stimulation of the mouse tail, ear, or cultured calvarias with heat shock (generated by heating, ultrasound, or laser), a distinct Cre-mediated excision was observed in cells stimulated by these physical factors with minimal occurrence of leaky reporter expression. The application of heat shock to Hsp70-CreERT2; FGFR2-P253R double transgenic mice or Hsp70-CreERT2 mice infected with AAV-BMP4 at calvarias induced the activation of Cre-dependent mutant FGFR2-P253R or BMP4 respectively, thereby facilitating the premature closure of cranial sutures or the repair of calvarial defects. This novel mouse line holds significant potential for investigating the underlying mechanisms of physical therapy, tissue repair and regeneration, lineage tracing, and targeted modulation of gene expression of cells in local tissue stimulated by physical factor at the interested time points. KEY MESSAGES: In the study, an Hsp70-CreERT2 transgenic mouse was generated for heat shock-induced gene modulation. Heat shock, ultrasound, and laser stimulation effectively activated Cre expression in Hsp70-CreERT2; reporter mice, which leads to deletion of floxed DNA sequence in the tail, ear, and cultured calvaria tissues of mice. Local laser stimuli on cultured calvarias effectively induce Fgfr2-P253R expression in Hsp70-mTmG-Fgfr2-P253R mice and result in accelerated premature closure of cranial suture. Heat shock activated AAV9-FLEX-BMP4 expression and subsequently promoted the repair of calvarial defect of Hsp70-CreERT2; Rosa26-mTmG mice.

Creating Deep Traps in Yttrium Aluminum Garnet for Long‐Term Optical Storage and Afterglow‐Intensity‐Ratio‐Based Temperature Sensing

AbstractDeep traps are needed for electron‐trapping‐based long‐term optical storage due to its resistance to thermal erasure. Current electron trapping materials have the erasing temperatures hardly beyond 600 K, limiting its storage time. Herein, an electron trapping material containing deep traps is achieved by co‐doping Tb and Eu in Y3Al5O12 via solid‐state reaction in reducing atmosphere. After 254 nm UV charging, strong thermoluminescence of Tb3+ with the glow curve peaking at 600, 693, and 765 K is observed. The comparative studies of the as‐made and the air‐annealed samples suggest that these new traps are related to the complex defects containing oxygen vacancy with adjacent Eu2+ and the charging process is the photoionization of Tb3+ with subsequent electron trapping. The 693 and 765 K thermoluminescence glow peaks in the charged sample show almost no decrease during 108 h storage in dark at room temperature. Images write‐in and read‐out via 808 nm laser stimulation are realized. Furthermore, the present phosphor also exhibits temperature‐sensitive afterglow spectra in the range of 553–803 K with the sensing span of 250 K wider than other afterglow thermometers. These findings indicate the great application potentials of Y3Al5O12:Tb,Eu phosphor in long‐term optical storage and temperature sensing.

Investigation of directional discrimination in the nociceptive system using temperature-controlled laser stimuli.

Cutaneous laser stimulation has commonly been employed to investigate the thermal properties of the nociceptive system. The aim of this study was to investigate how a temperature-controlled laser system improves the assessment of directional discrimination in the nociceptive system. In total, twenty healthy volunteers participated in this study. To determine the directional discrimination threshold (stimulation length 50% correct, expressed in mm), thermal stimuli were delivered using a diode laser and the laser beam was perpendicularly displaced across the skin to give a linear stimulation in four different directions (distal, proximal, lateral and medial) and displacement lengths (3 for lateral-medial and 5 for distal-proximal). Two temperature control modes were used in the stimulation system, open-loop and closed-loop control. The subjects had to report the perceived stimulus direction, the degree of certainty regarding the perceived direction and the intensity of the perceived stimulus (0-10 numerical rating scale, 3: pain threshold). During closed-loop control, the orientation of stimuli was discriminated significantly more accurately than during open-loop control. During closed-loop control, the directional discrimination threshold was 31.9 and 26.1 mm for distal-proximal and lateral-medial directed stimuli, respectively. A numerical rating scale was significantly higher for the lateral/medial directions. Moreover, the variability of the discrimination threshold is reduced in the closed-loop control system. The findings show that discrimination ability is better in the lateral-medial directions compared to the distal-proximal directions. This study indicates that using a system enabling closed-loop temperature control, allows more robust probing of the temporo-spatial mechanisms in the nociceptive system. This study shows that a newly developed temperature-controlled laser stimulation system enhances the possibilities to investigate the nociceptive temporo-spatial integration, as shown by a less variable directional discrimination threshold. The results also show that different orthogonal directions are discriminated differently. This new method allows a better investigation of the combined temporal and spatial mechanisms in the nociceptive system.

Heterosynaptic plasticity of the visuo-auditory projection requires cholecystokinin released from entorhinal cortex afferents.

The entorhinal cortex is involved in establishing enduring visuo-auditory associative memory in the neocortex. Here we explored the mechanisms underlying this synaptic plasticity related to projections from the visual and entorhinal cortices to the auditory cortex in mice using optogenetics of dual pathways. High-frequency laser stimulation (HFS laser) of the visuo-auditory projection did not induce long-term potentiation. However, after pairing with sound stimulus, the visuo-auditory inputs were potentiated following either infusion of cholecystokinin (CCK) or HFS laser of the entorhino-auditory CCK-expressing projection. Combining retrograde tracing and RNAscope in situ hybridization, we show that Cck expression is higher in entorhinal cortex neurons projecting to the auditory cortex than in those originating from the visual cortex. In the presence of CCK, potentiation in the neocortex occurred when the presynaptic input arrived 200 ms before postsynaptic firing, even after just five trials of pairing. Behaviorally, inactivation of the CCK+ projection from the entorhinal cortex to the auditory cortex blocked the formation of visuo-auditory associative memory. Our results indicate that neocortical visuo-auditory association is formed through heterosynaptic plasticity, which depends on release of CCK in the neocortex mostly from entorhinal afferents.

Crown-ether threaded covalent organic polyrotaxane framework (COPF) towards synergistic crown/Zn2+/photothermal/photodynamic antibacterial and infected wound healing therapy

Controllable preparation of materials with new structure has always been the top priority of polymer materials science research. Here, the supramolecular binding strategy is adopted to develop covalent organic frameworks (COFs) with novel structures and functions. Based on this, a two-dimensional crown-ether ring threaded covalent organic framework (COF), denoted as Crown-COPF with intrinsic photothermal (PTT) and photodynamic (PDT) therapeutic capacity, was facilely developed using crown-ether threaded rotaxane and porphyrin as building blocks. Crown-COPF with discrete mechanically interlocked blocks in the open pore could be used as a molecular machine, in which crown-ether served as the wheel sliding along the axle under the laser stimulation. As a result, Crown-COPF combining with the bactericidal power of crown ether displayed a significant photothermal and photodynamic antibacterial activity towards both the Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus), far exceeding the traditional Crown-free COF. Noteworthily, the bactericidal performance could be further enhanced via impregnation of Zn2+ ions (Crown-COPF-Zn) flexible coordinated with the multiple coordination sites (crown-ether, bipyridine, and porphyrin), which not only endow the positive charge with the skeleton, enhancing its ability to bind to the bacterial membrane, but also introduce the bactericidal ability of zinc ions. Notably, in vivo experiments on mice with back infections indicates Crown-COPF-Zn with self-adaptive multinuclear zinc center, could effectively promote the repairing of wounds. This study paves a new avenue for the effectively preparation of porous polymers with brand new structure, which provides opportunities for COF and mechanically interlocked polymers (MIPs) research and applications.

Evaluating peripheral neuromuscular function with brief movement-evoked pain.

Movement-evoked pain is an understudied manifestation of musculoskeletal conditions that contributes to disability, yet little is known about how the neuromuscular system responds to movement-evoked pain. The present study examined whether movement-evoked pain impacts force production, electromyographic (EMG) muscle activity, and the rate of force development (RFD) during submaximal muscle contractions. Fifteen healthy adults (9 males; age = 30.3 ± 10.2 yr, range = 22-59 yr) performed submaximal isometric first finger abduction contractions without pain (baseline) and with movement-evoked pain induced by laser stimulation to the dorsum of the hand. Normalized force (% maximal voluntary contraction) and RFD decreased by 11% (P < 0.001) and 15% (P = 0.003), respectively, with movement-evoked pain, without any change in normalized peak EMG (P = 0.77). Early contractile RFD, force impulse, and corresponding EMG amplitude computed within time segments of 50, 100, 150, and 200 ms relative to the onset of movement were also unaffected by movement-evoked pain (P > 0.05). Our results demonstrate that movement-evoked pain impairs peak characteristics and not early measures of submaximal force production and RFD, without affecting EMG activity (peak and early). Possible explanations for the stability in EMG with reduced force include antagonist coactivation and a reorganization of motoneuronal activation strategy, which is discussed here.NEW & NOTEWORTHY We provide neurophysiological evidence to indicate that peak force and rate of force development are reduced by movement-evoked pain despite a lack of change in EMG and early rapid force development in the first dorsal interosseous muscle. Additional evidence suggests that these findings may coexist with a reorganization in motoneuronal activation strategy.

TiO2-Ti3C2 Nanocomposites Utilize Their Photothermal Activity for Targeted Treatment of Colorectal Cancer.

The search for effective and low-risk treatment methods for colorectal cancer (CRC) is a pressing concern, given the inherent risks and adverse reactions associated with traditional therapies. Photothermal therapy (PTT) has emerged as a promising approach for cancer treatment, offering advantages such as non-radiation, non-invasiveness, and targeted treatment. Consequently, the development of nanoparticles with high stability, biocompatibility, and photothermal effects has become a significant research focus within the field of PTT. In this study, TiO2-Ti3C2 nanocomposites were synthesized and characterized, and their photothermal conversion efficiency in the near-infrared region II (NIR-II) was determined. Then studied the in vivo and in vitro photothermal activity and anti-tumor effect of TiO2-Ti3C2 in human colorectal cancer cell lines and nude mice subcutaneous tumor model. The results showed that TiO2-Ti3C2 nanocomposites have strong absorption ability in the NIR-II, and have high photothermal conversion efficiency under 1064 nm (0.5 W/cm2, 6 min) laser stimulation. In addition, in vitro experiments showed that TiO2-Ti3C2 nanocomposites significantly inhibited the invasion, migration, and proliferation of colorectal cancer cells, and induced cell apoptosis; in vivo, experiments showed that TiO2-Ti3C2 nanocomposites-mediated PTT had good biocompatibility and efficient targeted inhibition of tumor growth. In conclusion, TiO2-Ti3C2 nanocomposites can be used as NIR-II absorption materials in PTT to suppress the invasion, migration, and proliferation of colorectal cancer cells, induce colorectal cancer cell apoptosis, and thus inhibit the development of CRC. Therefore, TiO2-Ti3C2 nanocomposites can be used as potential anti-tumor drugs for photothermal ablation of colorectal cancer cells.

Therapeutic efficacy and safety of home-based portable laser irradiation on patients with wrist pain: a single-blinded randomized controlled trial

The purpose of this study is to confirm the effect of small, portable low-level laser therapy (light sources in square configuration: 830 nm GaAs diode 3.2 mW at the center, 4 × 650 nm InGaAIP diodes over the corners) treatment in reducing and enhancing hand function in patients with wrist pain. This study was a prospective, randomized, sham-controlled, and home-based self-therapy trial. A total of thirty subjects with wrist pain were enrolled. All participants received low-level laser therapy on painful area at the wrist. The experimental group (n = 15) received laser stimulation, while the control group (n = 15) received sham stimulation using identical equipment that generated only a red light without the laser output. Both groups self-treated for 30 min a day, 5 days per week for 3 weeks, total of 15 sessions. The primary outcome was assessed using a visual analogue scale (VAS) for wrist pain from 0 (painless) to 10 (extreme pain). The secondary outcomes were measured with patient-rated wrist evaluation (PRWE), grip strength, lateral, palmar, and tip pinch strength. Measures were taken before and after treatment. A total of thirty participants provided outcome data. After the intervention, both groups showed a significant decrease in VAS score, from 4.93 to 3.67 in experimental group, from 5.53 to 4.00 in control group (the experiment group: p = 0.020, the control group: p = 0.003). The experimental group showed a significant improvement in function scale score (p = 0.012), the control group did not. Lateral and pinch strength was significantly improved in the experimental group (p = 0.017) and in the control group (p = 0.034) respectively. There were no side effects in the patients. Medical laser irradiation is a portable and easy-to-use laser irradiator without side effects. Clinical Trial Registration number: KCT0006604.

In Situ Electrochemical Construction of CuN3@CuCl Hybrids for Controllable Energy Release and Self-Passivation Ability.

Advanced energetic materials (EMs) play a crucial role in the advancement of microenergetic systems as actuation parts, igniters, propulsion units, and power. The sustainable electrosynthesis of EMs has gained momentum and achieved substantial improvements in the past decade. This study presents the facile synthesis of a new type of high-performance CuN3@CuCl hybrids via a co-electrodeposition methodology utilizing porous Cu as the sacrificial template. The composition, morphology, and energetic characteristics of the CuN3@CuCl hybrids can be easily tuned by adjusting the deposition times. The resulting hybrids demonstrate remarkable energy output (1120 J·g-1) and good laser-induced initiating ability. As compared with porous CuN3, the uniform doping of inert CuCl enhances the electrostatic safety of the hybridized material without compromising its overall energetic characteristics. Notably, the special oxidizing behavior of CuCl gradually lowers the susceptibility of the hybrid material to laser and electrostatic stimulation. This has significant implications for the passivation or self-destruction of highly sensitive EMs. Overall, this study pioneers a new path for the development of MEMS-compatible EMs, facilitating further microenergetic applications.

Bufotalin-loaded biomimetic Prussian blue nanoparticles for colorectal cancer chemo-photothermal ferroptosis therapy.

Purpose: We constructed biomimetic nanoparticles with biocompatible, tumor-targeting, laser-responsive properties for ferroptosis-induced colorectal cancer chemo-photothermal therapy, with the aim to realize double-hit ferroptosis treatment for colorectal cancer. Methods: The nanoparticles were prepared by first loading the chemotherapy drug bufotalin (CS-5) with Prussian blue (PB), then combining a hybridized erythrocyte-tumor membrane (M) with PB@CS-5 to produce PB@CS-5@M. The chemo-photothermal therapy efficiency of PB@CS-5@M was tested by in vitro and in vivo experiments. Results and conclusion: The combined PB and CS-5 act as promising ferroptosis inducers to enhance ferroptosis efficacy. The hyperthermia induced by laser stimulation can trigger PB to release CS-5 and iron and ferrous ions, which further promotes ferroptosis.

Er3+-activated Ba2V2O7 upconversion nanosheets for dual-mode temperature sensing.

So far, there has been substantial research on non-contact luminescence thermometry approaches that rely on luminescence intensity ratio (LIR) technology. However, there is limited availability of phosphors doped with Er3+ ions that exhibit on-par luminescence and high sensitivity. In this work, samples of Ba2V2O7:Er3+ were synthesized using a sol-gel method aided by citric acid. The luminescence properties of these samples, including upconversion and down-shifting, were investigated using both ultraviolet and 980 nm laser stimulation. When subjected to ultraviolet (UV) light, the sample exhibits a distinct broadband emission that appears pale green. This emission is a distinguishing property of the sample and is attributed to the presence of V2O72- ions. Upon being stimulated by a 980 nm laser, the sample exhibits standard green up-conversion Er3+ emission bands. Concurrently, an assessment was conducted on the phosphor's ability to measure temperature by analysing the LIR between the thermally coupled 2H11/2, 4S3/2 energy levels (TCELs) and the non-thermally coupled 2H11/2, 4F9/2 energy levels (NTCELs) of the Er3+ ion. The corresponding highest sensitivity of temperature for TCELs and NTCELs can position Ba2V2O7:Er3+ nanosheets as a capable option for materials utilized in temperature-sensing applications.

Advancements in Portable Deuterium Reactor Systems: A Multifaceted Scientific Investigation

Deuterium, an isotope of hydrogen, holds significant promise across a spectrum of scientific and industrial domains, particularly within the realms of nuclear technology, chemistry, and pharmaceuticals. This comprehensive review explores the multifaceted applications and implications of deuterium utilization, spanning from its role in nuclear fusion reactors to its incorporation into organic molecules for medicinal purposes. In the field of nuclear fusion, deuterium serves as a primary fuel source, offering the potential for clean, sustainable energy production through controlled fusion reactions. Detailed experimental studies have revealed the efficacy of electrolysis-based methods for deuterium enrichment, leading to substantial increases in deuterium concentration within water and organic solvents. Moreover, novel approaches such as laser stimulation have been investigated to enhance the efficiency of deuterium extraction and fusion processes. Beyond nuclear fusion, deuterium finds extensive use in organic chemistry, where isotopic labeling techniques enable the synthesis of deuterated compounds with altered chemical and pharmacokinetic properties. This includes the production of deuterated polyunsaturated fatty acids (D-PUFAs), offering new avenues for drug development and metabolic research. Economically, the commercialization of deuterium-based technologies presents lucrative opportunities for industries involved in energy production, pharmaceuticals, and materials science. The increasing demand for deuterated compounds underscores the importance of efficient and sustainable methods for deuterium extraction and enrichment. Looking ahead, ongoing research endeavors aim to further optimize deuterium-related processes, enhance fusion reactor efficiency, and explore novel applications in fields such as isotope geochemistry and environmental remediation. However, challenges remain, including the scalability of deuterium production, regulatory hurdles, and geopolitical considerations surrounding deuterium-rich regions. In conclusion, the comprehensive examination of deuterium's diverse applications underscores its pivotal role in advancing scientific understanding and technological innovation. By harnessing its unique properties, researchers and industries alike stand poised to unlock new frontiers in energy, medicine, and beyond.

Iridium(III) complexes decorated with silicane-modified rhodamine: near-infrared light-initiated photosensitizers for efficient deep-tissue penetration photodynamic therapy.

Meeting the demand for efficient photosensitizers in photodynamic therapy (PDT), a series of iridium(III) complexes decorated with silicane-modified rhodamine (Si-rhodamine) was meticulously designed and synthesized. These complexes demonstrate exceptional PDT potential owing to their strong absorption in the near-infrared (NIR) spectrum, particularly responsive to 808 nm laser stimulation. This feature is pivotal, enabling deep-penetration laser excitation and overcoming depth-related challenges in clinical PDT applications. The molecular structures of these complexes allow for reliable tuning of singlet oxygen generation with NIR excitation, through modification of the cyclometalating ligand. Notably, one of the complexes (4) exhibits a remarkable ROS quantum yield of 0.69. In vivo results underscore the efficacy of 4, showcasing significant tumor regression at depths of up to 8.4 mm. This study introduces a promising paradigm for designing photosensitizers capable of harnessing NIR light effectively for deep PDT applications.

Synthesis of Pt-MoS2 with enhanced photothermal and peroxidase-like properties and its antibacterial application.

Despite tremendous efforts, bacterial infection and contamination remain a major clinical challenge to modern humans. Nanozyme materials with stimuli-responsive properties are expected to be powerful tools for the next generation of antibacterial therapy. Here, MoS2 nanosheet was firstly prepared by liquid phase exfoliation method, and Pt-MoS2 hybrid biomaterial was then successfully synthesized by a simple self-reduction method. The Pt decoration significantly improves the photothermal effect of MoS2 nanosheet under 808 nm NIR laser irradiation. Besides, benefiting from the formation of heterogeneous structure, the Pt-MoS2 has significantly enhanced peroxidase mimetic catalytic activity, which can kill bacteria through catalysis of H2O2 to generate antimicrobial hydroxyl radicals. Moreover, the temperature rise brought about by NIR laser stimulation further amplifies the nanozyme activity of the composites. After treatment by the synergistic platform, both Staphylococcus aureus and Escherichia coli can be effectively inhibited, demonstrating its broad-spectrum antibacterial properties. In addition, the developed antibacterial Pt-MoS2 nanozyme have the excellent biocompatibility, which makes them well suited for infection elimination in biological systems. Overall, this work shows great potential for rationally combining the multiple functions of MoS2-based nanomaterials for synergistic antibacterial therapy. In the future, the Pt-MoS2 nanozyme may find wider applications in areas such as personal healthcare or surface disinfection treatment of medical devices.

Optical Modulation of the Blood-Brain Barrier for Glioblastoma Treatment.

The blood-brain barrier (BBB) is a major obstacle to the diagnostics and treatment of many central nervous system (CNS) diseases. A prime example of this challenge is seen in glioblastoma (GBM), the most aggressive and malignant primary brain tumor. The BBB in brain tumors, or the blood-brain-tumor barrier (BBTB), prevents the efficient delivery of most therapeutics to brain tumors. Current strategies to overcome the BBB for therapeutic delivery, such as using hyperosmotic agents (mannitol), have impeded progress in clinical translation limited by the lack of spatial resolution, high incidences of complications, and potential for toxicity. Focused ultrasound combined with intravenously administered microbubbles enables the transient disruption of the BBB and has progressed to early-phase clinical trials. However, the poor survival with currently approved treatments for GBM highlights the compelling need to develop and validate treatment strategies as well as the screening for more potent anticancer drugs. In this protocol, we introduce an optical method to open the BBTB (OptoBBTB) for therapeutic delivery via ultrashort pulse laser stimulation of vascular targeting plasmonic gold nanoparticles (AuNPs). Specifically, the protocol includes the synthesis and characterization of vascular-targeting AuNPs and a detailed procedure of optoBBTB. We also report the downstream characterization of the drug delivery and tumor treatment efficacy after BBB modulation. Compared with other barrier modulation methods, our optical approach has advantages in high spatial resolution and minimally invasive access to tissues. Overall, optoBBTB allows for the delivery of a variety of therapeutics into the brain and will accelerate drug delivery and screening for CNS disease treatment. Key features • Pulsed laser excitation of vascular-targeting gold nanoparticles non-invasively and reversibly modulates the blood-brain barrier permeability. • OptoBBTB enhances drug delivery in clinically relevant glioblastoma models. • OptoBBTB has the potential for drug screening and evaluation for superficial brain tumor treatment.

Thermo-photobiomodulation of stem cells

The most important task of cell transplantology is to activate the proliferative potential of mesenchymal stem cells (MSCs) before receiving bone marrow cells from a donor. This is necessary to increase a sufficient number of MSCs in early passages, when the probability of chromosomal mutations is still low. The proliferative activity of cells can be activated using photobiomodulation (PBM) by exposure to lowintensity laser radiation in the visible and near-infrared ranges. Recently, it was shown in vitro that the combination of PBM and moderate laserinduced heating can lead to a significant increase in the efficiency of MSC colony formation. The main objectives of the study are to find the optimal parameters for such a combined effect and answer the question about the possibility of a synergistic effect of thermal heating and laser radiation. MSCs isolated from rat bone marrow were used for the experiments. MSCs were exposed to short-term laser radiation of moderate power with a wavelength of 980 nm and an energy density of 68-340 J/cm2, accompanied by moderate heating of the cell suspension. Vials with grown colonies were photographed, then their number, size and number of cells in individual colonies were determined using special digital image processing methods. It was found that under optimal parameters, exposure to laser radiation of moderate power leads to an increase in the number of colonies by 4.1±0.5 times, and the total number of cells by 3.3±0.4 times compared to the control. It has been shown that this increase in cell number occurs as a result of the synergistic effect of photobiomodulation and moderate heating. Activation of colony formation after laser stimulation of MSCs occurs due to the migration of cells from the initially formed colonies with the subsequent formation of additional colonies by separated cells.